DISPLAY WEEK 2015 REVIEW AND METROLOGY...

DISPLAY WEEK 2015 REVIEW AND METROLOGY ISSUE

Official Publication of the Society for Information Display bull wwwinformationdisplayorgSeptOct 2015

Vol 31 No 5

Sep-Oct Cover_SID Cover 9122015 432 PM Page 1

2 Editorial Down the Path of Display Historyn By Stephen P Atwood

3 Industry Newsn By Jenny Donelan

4 Guest Editorial Technical Progress Should Not Overwhelm Common Sensen By Tom Fiske

Display Week 2015 Review6 Display Week Review Introduction Chinese Displays Light-Field Displays and

Automotive Technology Lead Trends at Display Week 2015 Chinese display companies showed up in force this year adding excitement to an already dazzling exhibithall of displays in sizes ranging from micro to downright huge A couple of futuristic table-top displays anda wealth of automotive displays also commanded attention Information Displayrsquos roving reporters were onthe scene to describe these and other advances n By Jenny Donelan

8 I-Zone and Best-in-Show WinnersThe Society for Information Display honored six exhibiting companies at Display Week 2015 in San Joselast June These companies were Ubiquitous Energy for best prototype in the Innovation Zone and AUOBOE Fogale Sensation Nanosys and Nippon Electric Glass for Best-in-Show winners on the main exhibitfloorn By Jenny Donelan

12 Image Quality and MetrologyDisplay technology delivers the photons to the front of the screen the human vision system detects the photons and perceives an image Measurement devices capture and analyze image characteristics and deliverobjective quantities that engineers use to inform optical designs and monitor manufacturing processesn By Tom Fiske

16 Display Materials and ProcessesIn addition to three major categories of new and evolving display materials ndash display glass flexible transparent conductors and quantum dots ndash a potentially disruptive material-and-process combination appeared at Display Week this year n By Ken Werner

24 Microdisplays Near-to-Eye and 3-DNew display technologies including some new twists on tried-and-true display technologies are helping displays integrate ever more seamlessly with the devices we use every day n By Steve Sechrist

Display Metrology30 Frontline Technology A General Framework for Measuring the Optical Performance of

Displays under Ambient IlluminationThe growing diversity of the display landscape requires a unified approach to characterize visual performanceunder realistic lighting conditionsn By John Penczek Edward F Kelley and Paul A Boynton

36 Frontline Technology Advanced Imaging ColorimetryImplementing advanced methods of display metrology enables highly accurate luminance and color-imagingmeasurements to be performed The next generation of high-accuracy imaging colorimeters benefits from acombined approach of recording additional data and utilizing a matrix-based optimization algorithmn By Đenan Konjhodžić Peter Khrustalev and Richard Young

41 SID News International Display Workshops to Take Place in Otsu Japan

44 Corporate Members

44 Index to Advertisers

Information Display 515 1

SEPTEMBEROCTOBER 2015VOL 31 NO 5

InformationDISPLAYcontents

For Industry News New Products Current and Forthcoming Articles see wwwinformationdisplayorg

INFORMATION DISPLAY (ISSN 0362-0972) is published 6 times ayear for the Society for Information Display by Palisades ConventionManagement 411 Lafayette Street 2nd Floor New York NY 10003William Klein President and CEO EDITORIAL AND BUSINESSOFFICES Jay Morreale Editor-in-Chief Palisades ConventionManagement 411 Lafayette Street 2nd Floor New York NY 10003telephone 212460-9700 Send manuscripts to the attention of theEditor ID SID HEADQUARTERS for correspondence on sub-scriptions and membership Society for Information Display 1475 S Bascom Ave Ste 114 Campbell CA 95008 telephone 408879-3901 fax -3833 SUB SCRIP TIONS Information Display is distributedwithout charge to those qualified and to SID members as a benefit ofmembership (annual dues $10000) Subscriptions to others US ampCanada $7500 one year $750 single copy elsewhere $10000 oneyear $750 single copy PRINTED by Wiley amp Sons PERMISSIONSAbstracting is permitted with credit to the source Libraries are per-mitted to photocopy beyond the limits of the US copyright law forprivate use of patrons providing a fee of $200 per article is paid to theCopyright Clearance Center 21 Congress Street Salem MA 01970(reference serial code 0362-097215$100 + $000) Instructors arepermitted to photocopy isolated articles for noncommercial classroomuse without fee This permission does not apply to any special reportsor lists published in this magazine For other copying reprint orrepublication permission write to Society for Information Display 1475S Bascom Ave Ste 114 Campbell CA 95008 Copyright copy 2015Society for Information Display All rights reserved

In the Next Issue ofInformation Display

Lighting and ImagingTechnologies and Applicationsbull Light-Field Imagingbull Indoor Scene Understanding with

RGB-D Imagesbull Melanopsin Receptorsbull Human Productivity and Lightingbull OLED Panels with Low Blue Currentbull History of Information Display

Magazine

SIDSOCIETY FOR INFORMATION DISPLAY

Vol 31 No 5

Cover Design Acapella Studios Inc

ON THE COVER Scenes from Display Week 2015 include clockwise starting at upper right 110-incurved 4K TV from China Star Optoelectronics Technology (CSOT) (photo courtesy Steve Sechrist) Innovation Zone at Display Week Sharprsquos free-form LCD technology (photo courtesy Ken Werner) color E Ink samples slide from keynote address by Intelrsquos Brian Krzanich ribbon-cutting ceremony for Display Week exhibition applications for Kopin microdisplays (photo courtesy Steve Sechrist) 82-in10K display from Best-in-Show winner BOEand quantum-dot LCD exhibit with acrobatsfrom Nanosys

ID TOC Issue5 p1_Layout 1 9132015 453 PM Page 1

Down the Path of Display Historyby Stephen P Atwood

Some of you may have noticed that the 2015 issues ofInformation Display are labeled ldquoVolume 31rdquo This denotesthe 31st year of the modern era of Information Display I say ldquomodern erardquo because prior to 1985 (Volume 1 of ID)there was apparently a previous incarnation of SIDrsquos ldquoInformation Displayrdquo subtitled ldquoThe Journal of Data

Display Technologyrdquo and published by a separate company beginning sometimearound 1964 If you count this period then the publishing history of ID actually cov-ers some 50 years of the display industry by now One can easily imagine the depth ofevolution our industry has experienced in that time and what we might find by lookingback at older volumes of ID I found this idea particularly intriguing and started looking at older issues to seewhat was there I was very pleased to see the rich technical landscape of our industrydocumented by some great contributors some of whom are still active today Eachissue is a great read covering various topics that you may remember or that may fill insome missing information about the innovation steps that led to something that iscommonplace today Together these issues form an immensely valuable history of ourindustry that I want to see preserved and made available for everyone to enjoy So wehave embarked on a project to digitally scan and archive all the available back issuesof ID As these become ready we will be posting them on the Informationdisplayorgwebsite Thus far we have close to 30 back issues digitized and they are slowly beinguploaded to the website as time and resources allow so check back often to see whatgets added each month as we work through this projectAs an example of how interesting these back issues can be letrsquos take a look at whatwas happening in January 1995 roughly 20 years ago

January 1995 Issue of Information DisplayA very young looking editor named Ken Werner wrote about some of the presentationsat a recent Japanese technology conference where the focus was on developing theLCD manufacturing infrastructure in Japan and how the current production yieldswere not yet adequate Well-known companies such as Toshiba and NEC were opti-mistic that this could change soon and were making sizable investments as a resultThey were also very bullish about Japanrsquos ability to dominate the market share inLCDs for the foreseeable future Ken chronicled the familiar concerns about pricessupply and demand swings and margins for notebook manufacturers who were one ofthe main application targets for the young LCD industry at that time One interestingdata point was the push towards larger-sized motherglass sheets in manufacturingwith the goal being something around 500 times 600 mm This would enable 6-up 104-inpanels or 9-up 94-in panels and was expected to help bring costs down significantlyContrast this to todayrsquos LCD industry in which people continue to worry about pricessupply and demand swings and margins but are now manufacturing on motherglassformats over 2 m in length on a side and making many units of large HDTV panels ona single sheet Obviously todayrsquos LCD panels are radically more advanced than theywere in 1995 but that time frame was the nascent period of growth for both portablecomputing and LCDs

2 Information Display 515

Executive Editor Stephen P Atwood617306-9729 satwoodazonixcom

Editor-in-Chief Jay Morreale21246 0-9700 jmorrealepcm411com

Managing Editor Jenny Donelan603924-9628 jdonelanpcm411com

Global Advertising Director Stephen Jezzard sjezzardwileycom

Senior Account ManagerPrint amp E Advertising Roland Espinosa201-748-6819 respinosawileycom

Editorial Advisory BoardStephen P Atwood Chair

Azonix Corp USA

Helge SeetzenTandemLaunch Technologies Westmont Quebec

Canada

Allan KmetzConsultant USA

Larry WeberConsultant USA

Guest EditorsFlexible Technology and Wearables

Ruiqing (Ray) Ma Universal Display Corp

Applied VisionJames Larimer ImageMetrics

Automotive DisplaysSilvio Pala Denso International America

Touch and InteractivityBob SeniorCanatu

Display MetrologyTom Fiske Consultant

TV TechnologyAchin Bhowmik Intel Corp

Contributing EditorsAlfred Poor ConsultantSteve Sechrist ConsultantPaul Semenza ConsultantJason Heikenfeld University of Cincinnati Raymond M Soneira DisplayMate Technologies

InformationDISPLAY

The opinions expressed in editorials columns and feature articles do not necessarily reflect the opinions ofthe Executive Editor or Publisher of Information DisplayMagazine nor do they necessarily reflect the position ofthe Society for Information Display

editorial

(continued on page 43)

ID Editorial Issue5 p243_Layout 1 9122015 835 PM Page 2

Leyard Optoelectronic to Acquire Planar SystemsIn August Oregon-based display manufacturer Planar Systemsannounced that it would be acquired by a US affiliate of Leyard Opto-electronic a Chinese electronics manufacturer specializing in LED-based products The transaction is still subject to regulatory approvaland a shareholder vote by Planar but is expected to occur in the fourthquarter of 2015 Planarrsquos board unanimously approved the mergerGerry Perkel president and CEO of Planar said ldquoThe acquisition

by Leyard will provide our investors with a 42 premium to marketbased on our latest closing price and a 51 premium based on a 7-day volume-weighted average price of Planar common stock of $435 andwill position the Planar business for continued growth and innovationrdquo

DisplayMate Nods to Galaxy Note 5 in Shoot-outDisplayMate recently reviewed the Galaxy Note 5 and S6 edge smart-phones ndash in typical exhaustive fashion Its conclusion based on weeksof testing early production units sent to DisplayMate from SamsungHeadquarters in Korea ldquohellip the Galaxy Note 5 is the best-performingSmartphone display that we have ever tested It takes over from theGalaxy Note 4 which was the previous record holder for mobile-display performancerdquo For more information see httpwwwdisplaymate comGalaxy_Note5_ShootOut_1htm

Qualcomm Develops Update to Mirasol TechnologyUsing a structure comprising a mirror and an absorbing layer to takeadvantage of the wave properties of light researchers at QualcommMEMS Technologies Inc a subsidiary of Qualcomm Incorporatedhave developed a display technology that harnesses natural ambientlight to produce what it claims is an unprecedented range of colors anda superior viewing experience An article describing this approachrecently appeared in The Optical Societyrsquos journal Optica1This technology which is the latest version of an established com-

mercial product known as Qualcomm Mirasol is designed to reducethe amount of power used in multiple consumer-electronics productsBased on a new color-rendering format its creaters call ContinuousColor the new design may help solve problems affecting mobile displays such as how to provide an always-on display function withoutrequiring more frequent battery charging and a high-quality viewingexperience anywhere especially in bright outdoor environments___________1httpwwwosaorgen-usabout_osanewsroomnews_releases2015 mirror-like_display_creates_rich_color_pixels_by_h

Futaba Announces Flexible PMOLEDsFutaba Corporation has announced production availability of its flexi-ble passive-matrix OLED display The product is now being made atFutabarsquos plant in Kitaibaraki Japan It is ultra-thin ndash 03 mm in overallthickness ndash with a 14-in-diagonal black-and-white format supportinga resolution of 128 times 16 pixels at a minimum luminance of 600 cdm2

The display can be formed around any curved object with a radius of40 mm or larger Other notable benefits are that it is shatterproof ndashthereby easier to handle in assembly production lines ndash and very light-weight an advantage for wearable devices Wearables is one of themajor intended markets for the product

Philips Introduces New 55-in TVPhilips has added another quantum-dot-based display to its portfolioThe new 55-in 4K TV is based on QD Visionrsquos Color IQ optics andcomplements Philipsrsquo existing lineup of quantum-dot displays includ-ing a 27-in LCD monitor

Gooch amp Housego Has New 6-in-DiameterVeiling Glare Integrating SphereThe new Veiling Glare Measurement System from Gooch amp Housegowas designed for performing veiling-glare test measurements on sensorsamples in accordance with VESA 20 IDMS1 and other applicablestandards on measurement solutions The sphere consists of a sampleport light trap and two illumination sources all located on thespherersquos horizontal axis The sphere assembly also comes mounted toa rugged base plate Its internal surfaces and baffles are coated withGooch amp Housegorsquos Optolon2 high-reflectance coating which has aneffective wavelength range of 300ndash2500 nm n

industry news

Display Week 2016SID International Symposium Seminar amp Exhibition

May 22ndash27 2016Moscone Convention Center

San Francisco California USA

w w w d i s p l a y w e e k o r g

SAVE THE DATE

ID Industry News Issue5 p3_Layout 1 9122015 845 PM Page 3

Technical Progress Should Not OverwhelmCommon Senseby Tom Fiske

Welcome to the metrology issue of Information Displaymagazine Technical progress is inexorable As time goeson photon-catching detectors get more sensitive Sensorarrays get more pixels Computers process more data thanever before What we often need more of however is

common sense That is not to say that detector sensitivity numbers of sensors on achip or computational power are not important But they are not the only importantthings For these advancements to be useful one has to know what to do with theextra sensitivity and the additional data Our contributions this issue help us along theway of optimizing that extra data and computer power

We have two articles this month describing advances in metrology The first onefrom NIST scientists John Penczek and Paul Boynton and consulting display-metrologyexpert Ed Kelley recommends a standardized method for finding the optical perform-ance of displays in any ambient lighting environment They describe a common-senseextension of the principles in the Information Display Measurements Standard (IDMS)that cover emissive reflective and transparent displays With straightforward charac-terization of the reflective and transmissive properties of a display one can use theseprinciples to account for how ambient lighting will affect the visual performance ofalmost any display These authors show us how to use these principles to report theoptical properties of transparent displays in a variety of common lighting environments

The second article is by Đenan Konjhodžić Peter Khrustalev and Richard Young ofInstrument Systems GmbH They report on a new technique for extending the useful-ness and accuracy of an imaging colorimeter There are a few different paths one cantake to increase the accuracy in such a system Optimize the accuracy of the ldquoCIErdquofilters increase the number of filters used for the colorimetric measurements or use aset of accurate spectro radiometric measurements of a typical spectral power distribu-tion (SPD) to construct a transformation matrix There will always be some deviationin the CIE matching filters Increasing filters adds time and cost Matrices increaseaccuracy but limit the system to measuring accurately only a narrow range of SPDsKonjhodžić and colleagues propose a method that uses six filters and a range of train-ing spectra Optimization and appropriate choice and weighting of the training spectraimprove the transformation matrices and increase the accuracy of the system for a general range of SPDs

I had the privilege of reporting on Display Week for Information Display magazineAlong with several others we covered various aspects of the event by writing blogs(httpidmagazinedisplayweek2015blogspotcom) and articles for this edition of IDAlthough not strictly part of the metrology issue my article covers image quality andmetrology for Display Week 2015 In it you will find my take on high-dynamic-rangeand extended-gamut displays as well as on recent offerings from display-measurementsystem providers n

Tom Fiske is currently a consultant specializing in display technology image quality and optical metrology He has been on the technical staff at Qualcomm Rockwell Collins Philips Electronics dpiX LLC and Xerox PARC He can be reached at tgfiskegmailcom

guest editorialSID EXECUTIVE COMMITTEE

President A GhoshPresident-Elect Y S KimRegional VP Americas A BhowmikRegional VP Asia B WangRegional VP Europe P KathirgamanathanTreasurer H SeetzenSecretary T TsujimuraPast President B Berkeley

DIRECTORSBangalore T RuckmongathenBay Area J PollackBeijing X YanBelarus A SmirnovCanada J ViethGreater Dayton D G HopperDelaware Valley J W Parker IIIMetropolitan Detroit J KanickiFrance F TemplierHong Kong H S KwokIndia S SambandanIsrael G GolanJapan K KondohKorea K-W WhangLatin America A MammanaLos Angeles L TannasMid-Atlantic J KymissisMid-Europe H De SmetNew England S AtwoodPacific Northwest A AbileahRussia V BelyaevSingapore T WongSouthwest S OrsquoRourkeTaipei J ChenTexas Z YanivUK amp Ireland S DayUkraine V SerganUpper Mid-West B Bahadur

COMMITTEE CHAIRSAcademic P BosArchives L Tannas JrAudit S OrsquoRourkeBylaws A SilzarsChapter Formation ndash Europe H De SmetConventions P DrzaicConventions Vice-Chair BC and MC J JacobsConventions Vice-Chair Europe I SageConventions Vice-Chair Asia K-W WhangDefinitions amp Standards T FiskeDisplay Industry Awards W ChenHonors amp Awards F LuoI-Zone B SchowengerdtInvestment H SeetzenLong-Range Planning Y S KimMembership H-S KwokMembership Vice-Chair Social Media H AtkuriNominating B BerkeleyPublications H SeetzenSenior Member Grade Y S KimWeb Site H Seetzen

CHAPTER CHAIRSBangalore S SambadamBay Area R RaoBeijing N XuBelarus V A VyssotskiCanada A KitaiDayton J LuuDelaware Valley J BlakeDetroit J ByrdFrance L VignauHong Kong M WongIndia S KauraIsrael I Ben DavidJapan K KondoKorea S T ShinLatin America V MammanaLos Angeles L IboshiMid-Atlantic G MelnikMid-Europe H J LempNew England J GandhiPacific Northwest K YugawaRussia M SychovSingaporeMalaysia C C ChaoSouthwest M StrnadTaipei C C WuTexas R FinkUK amp Ireland M JonesUkraine V SorokinUpper Mid-West R D Polak

SOCIETY FOR INFORMATION DISPLAY1475 S Bascom Ave Ste 114 Campbell CA 95008408879-3901 e-mail officesidorghttpwwwsidorg

ID Guest Editorial Issue5 p4_Layout 1 9132015 1250 PM Page 4

KONICA MINOLTA SENSING AMERICAS INC bull 101 Williams Drive Ramsey NJ 07446 bull Toll Free (888) 473-2656 bull Outside US (201) 236-4300 bull sensingkonicaminoltaus

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For superior color and luminance measurement capabilities that can get the results you need choose Konica Minoltarsquos CS-2000 Spectroradiometer or the CA-310 Display Color Analyzer They provide fast highly accurate color and luminance measurements for low luminance display measurements including popular backlit LED displays

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ONEOF THE BEST aspects of DisplayWeek is discovering how much progress hasbeen made from one year to the next Some-times this progress is expected or hoped for ndashremember when the big OLED TVs finally hitthe show floor a couple of years ago Some-times it is surprising ndash be sure to read aboutmicro-LEDs in contributor Ken Wernerrsquos Display Week review on materials in this issue This year the editors of Display Week com-pared notes after the show about what reallyimpressed us We came up with three majorthemes working light-field demonstrationsan aggressive ramp-up in the area of vehicledisplays (they were everywhere at the show)and last but not least some major demos of large-area displays from Chinese manufacturers

Our team of roving reporters blogged fromthe show about what they saw Tom Fiskealerted us to what was going on in metrologySteve Sechrist covered microdisplays near-to-eye and 3D Ken Werner looked at new mate-rials and Geoff Walker wrote about touch Ifyou missed these blog entries before you can

read them again now Check out our writersrsquoimpressions on Information Displayrsquos showblog at httpidmagazinedisplayweek2015blogspotcom And you can read their fullarticles on metrology microdisplays and 3Dand materials in this issue

As always we are indebted to our contribu-tors Herersquos a quick look at highlights fromtheir pieces in this issue accompanied by afew of our own notes Here are the technolo-gies that caught our eyes and our imaginationsat the show starting with some notable displays from China

China RisesEveryone in the industry knows that Chinesedisplay manufacturing is now a powerhouse interms of overall production This was the firstyear at Display Week however that productsfrom China made such a strong appearance atthe show These companies have made realprogress in recent years in terms of innova-tion Among the many worthy Chinese firmsin the exhibit hall (including the InnovationZone) were certain standouts including BOECCDL CSOT and SuperD

As noted in the Best-in-Show article in thisissue BOE Technology Group won an award

in the Large-Exhibit Category for its 82-in10K display With its vibrant imagery thispanel was one of those products that stoppedmany showgoers in their tracks Although the10240 times 4320 pixel display was a prototypecreated to demonstrate how high high resolu-tion can go the company says that mass production of similar products is not far offItrsquos amazing to think that we might have TVsof this resolution in our living rooms in a couple of years ndash hopefully with some worthycontent to go with them

Another display that had showgoers pausingto admire it was a huge (20 square meters)LED-based 3D display from CCDL (CentralChina Display Laboratories) that showed life-size and larger imagery ndash pretty arresting when extremely large objects looked like they werecoming right at you (Fig 1) This HD stereo-scopic display for indoor use required glassesbut presented a fairly wide central viewingarea for the 3D effect and could certainly beviewed by multiple people The pixel pitch ofthe demo display was 6 mm with a resolutionof 960 times 576 CCDL also offers these indoordisplays in 8- and 10-mm pixel pitches

Shenzhen-based China Star OptoelectronicsTechnology (CSOT) was also at Display Week

Chinese Displays Light-Field Displays andAutomotive Technology Lead Trends atDisplay Week 2015 Chinese display companies showed up in force this year adding excitement to an already dazzling exhibit hall of displays in sizes ranging from micro to downright huge A couple offuturistic table-top displays and a wealth of automotive displays also commanded attentionInformation Displayrsquos roving reporters were on the scene to describe these and otheradvances

by Jenny Donelan

Jenny Donelan is the Managing Editor ofInformation Display She can be reached at jdonelanpcn411com

6 Information Display 5150362-097252015-006$100 + 00 copy SID 2015

review introduction

ID Donelan-Trends p6-7_Layout 1 9132015 309 PM Page 6

with its 110-in curved 4K TV (Fig 2) claim-ing it as the ldquoworldrsquos largestrdquo curved LCD TVwith dimensions of 24 times 14 m The setincludes a 3840 times 2160 (4K times 2K) pixel display with 10-bit color at 60-Hz refresh and a 50K1 contrast CSOT product engineer Yuming Mo told Information Display contribu-ting editor Steve Sechrist that at its thinnest point (the edges) the curved set is only 20 mm thick with a curve radius of 5500 mm total

SuperD based in Shenzhen China hasdeveloped a second-screen mobile displaymonitor it calls 3D Box which shows 2D content from smartphones or tablets in auto-stereoscopic 3D via a wireless connectionwith the help of its eye-tracking software(For more about CSOT and SuperD seeSechristrsquos Display Week review on micro-displays and 3D in this issue)

Next-generation Displays in the I-ZoneLight-field and other 3D displays have thusfar belonged to the ldquofairly futuristicrdquo categoryof displays but there are signs that this ischanging ndash something we have been coveringin ID for quite a while now Two companiesin the Innovation Zone (Display Weekrsquos special exhibit space for cutting-edge displaytechnology in development) had table-top displays that went a good way toward bring-ing the future to us ndash or the other way aroundZebra Imaging showed a holographic light-field 3D display with a self-contained real-time spatial 3D generator device incorporatinga table-top display that it called the ZScapeThis was a full-color table-top display that didnot require special eyewear and offered com-patibility with most software platforms as well

as interactivity with off-the-shelf peripheralssuch as 3D tracking wands and gloves andgaming devices including pointers

Another exciting table-top display created a3D image that multiple users could see andmanipulate HoloDigilogrsquos display fromKorearsquos Human Media Research Center modified a conventional direct-view systemwith sub-viewing zones a lenslet array andlight-field technology with a QXGA (3840 times2160 pixel resolution) flat-panel display as thebase This display enabled multiple viewersto see a 3D image projected onto the 238-in-diagonal table-top panel (Fig 3) Accordingto Sechrist who also wrote about this technol-ogy and the Zebra Imaging demo in his Display Week review on microdisplays and3D in this issue the product looked surpris-ingly good for an early table-top demonstration

Automotive Displays at Display WeekDisplay manufacturers especially those com-panies dedicated to medical and industrialcustomers have long shown vehicle displaysat Display Week But where there used to betwo or three such displays per exhibitor thereare now whole rows or sections of boothsdevoted to this application This year DisplayWeek also featured a special technical sessiontrack on vehicle displays and trends Accord-ing to a recent report from IHS Technologyautomotive displays are projected to grow291 in 2015 and from what we saw at Display Week that figure sounds reasonable

3M was one of the companies with a newemphasis on vehicle display The company

was showing a line of films designed toenable brighter displays reduce glare andeliminate windshield reflection ndash all issuesinvolved with integrating LCDs in vehicles

Other companies with designated auto-motive display areas this year includedFujitsu JDI and Tianma MicroelectronicsUSA which shortly before the show rolledout two high-bright LCD panels with touchaimed at the automotive market Mentionmust also be made of Sharp for their free-formdisplay technology that allows panels to becut with curves and other novel shapes Thiswill certainly open up dashboard design possi-bilities in the near future Read how the company arrived at this technology in KenWernerrsquos review of materials in this issue

These examples are but several of all thatcould be seen at Display Week this year Besure to read our contributing editorrsquos offeringsto find out more and donrsquot miss Tom Fiskersquosexcellent update on metrology progress Display metrology may not make headlines inthe mainstream press but it underpins every-thing that display manufacturers do and is avital piece of our industry

Now that Display Week 2015 is behind usitrsquos exciting to think about what next yearrsquostop trends are going to be It seems safe tosay that Chinese manufacturers will continueto make progress in terms of innovation andnew products And we certainly look forwardto more novel types of displays such as thosebased on light fields and micro-LEDs We doknow that next year will feature special session tracks on augmented and virtual reality as well as digital signage No doubtthere will be surprises as well You will haveto attend the show to discover them first hand

n

Fig 1 The team from CCDL stands in frontof the companyrsquos LED-based 3D display providing an idea of how large this 3D display really was In the center is companypresident Chao Li Image courtesy CCDL

Fig 2 The CSOT team at Display Week(shown here with Display Week contributingeditor Steve Sechrist third from right) is justifiably proud of its 110-in 4K curved LCDTV Image courtesy Steve Sechrist

Fig 3 Holodigilogrsquos table-top panel displayprojected 3D imagery that could be seen andmanipulated by multiple users Image cour-tesy Steve Sechrist

EACH YEAR a committee of expertstravels the show floor at Display Week insearch of the exhibits that most deserve SIDrsquosBest-in-Show awards These awards honorthe most significant advances in display tech-nology and systems products prototypes andmanufacturing processes as presented byexhibitors Winners are chosen for their abilityto generate excitement not only within the display industry but among members ofthe general public as well as the global mediaand analyst communities The awards com-mittee considers not only a productrsquos signifi-cance but how effectively it is presented onthe show floor This yearrsquos five winners wereselected from more than 200 exhibitors

Also spotlighted in this article is the winnerof the Best Prototype Award bestowed bySIDrsquos Innovation Zone (I-Zone) committee on the most outstanding product in the I-ZoneDisplay Weekrsquos special exhibit area for early-stage technology

I-Zone Best PrototypeThis yearrsquos winner of the I-Zone award forBest Prototype at Display Week was UbiquitousEnergy for its ClearView Power Energy Har-vesting technology ClearViewrsquos technologyincorporates a transparent solar cell that canbe used to coat any surface to harvest ambientlight and generate electricity (Fig 1) The

transparent film covers the display area of arange of products ndash including wearablestablets and digital signage ndash transmitting lightvisible to the human eye while selectivelyconverting ultraviolet and near-infrared lightinto electricity to power the devices Thecompany states that its mission is to eliminatethe battery-life limitations of electronicdevices with this technology Spun out ofMIT Ubiquitous Energy is a Silicon Valley

company producing solar cells in its pilot-production facility in Redwood City CA

Best-in-Show WinnersFive companies ndash AUO BOE Fogale Sensation Nanosys and Nippon ElectricGlass ndash won Best-in-Show awards at DisplayWeek 2015 These awards are presented inthree categories of exhibit size largemedium and small

I-Zone and Best-in-Show WinnersThe Society for Information Display honored six exhibiting companies at Display Week 2015in San Jose last June These companies were Ubiquitous Energy for best prototype in theInnovation Zone and AUO BOE Fogale Sensation Nanosys and Nippon Electric Glass forBest-in-Show winners on the main exhibit floor

Compiled by Jenny Donelan

Jenny Donelan is Managing Editor of Information Display Magazine She can bereached at jdonelanpcm411com

the best of display week

Fig 1 Ubiquitous Energyrsquos ClearView film product is a solar cell that captures UV and IRlight to power electricity while allowing visible light to travel to viewersrsquo eyes

ID Donelan p8-10_Layout 1 9132015 107 PM Page 8

Large-Exhibit Category BOE TechnologyGroup won an award in the Large-Exhibit Category for its 82-in 10K display (Fig 2)This is the second year in a row the companyhas won in the large exhibit category ndash lastyear BOE received the award for an 8K display

According to Information Display Contrib-uting Editor Steve Sechrist this yearrsquos 10240times 4320 pixel display (in 219 format) was aone-off created to demonstrate the cuttingedge of high-resolution capabilities Thepanel uses a direct-LED-backlit schemePixel addressing is done from both top andbottom using a standard a-Si backplane Theend result notes Sechrist is stunning imageryBOE says work is on-going to modify thetechnology and prepare it for commercialrelease in the (not too distant) future

Medium-Exhibit Category AUO won anaward in the medium-exhibit category alsofor the second year in a row but this time forits 14-in full-circle AMOLED (Fig 3) Thisultra-slim and light display which features aresolution of 400 times 400 wide color gamutand low power consumption was acknowl-edged for its ability to meet upcoming trendsin wearable devices

AUO has successfully mass produced thesecircular displays applying special cut anddriver-IC designs to create a full circularshape To help meet demand for low powerconsumption in wearable devices AUO isleveraging the self-emissive nature ofAMOLED displays in combination with its

self-developed driver circuit to achieve morethan two times the duration of other smart-watches currently on the market AUO hasalso designed 15- and 16-in squareAMOLED displays as well as many othertypes of LCD products to meet ongoing wearable demands

Also winning in the medium-exhibit cate-gory was Nippon Electric Glass (NEG) for itsultra-thin G-Leaf glass (Fig 4) G-Leaf is lessthan 02 mm (200 microm) thick It is createdthrough overflow technology and maintainsthe advantages and reliability of glass but in afilm state By reducing thickness and weight

NEG has created an environmentally friendlydesign option in terms of material conserva-tion smaller carbon footprint and green processes This is a material with a great dealof potential for the next generation of applica-tions including electronics energy medicalsupplies and lighting

Small-Exhibit Category Fogale Sensationwon an award in the small-exhibit categoryfor its simultaneous touch and high-rangehovering technology (Fig 5) This technol-

Fig 2 BOE used imagery from a variety of European settings to show off the capabilities of its10K LED-backlit display

Fig 3 AUOrsquos 14-in full-circle AMOLEDdisplay features a lightweight low-powerdesign

Fig 4 Nippon Electric Glassrsquos G-Leaf glassis less than 02 mm thick and as a result isextremely flexible

Fig 5 Fogale Sensationrsquos hovering technol-ogy allows accurate input without touch

ogy brings additional functionality to thehumanndashmachine interface by adding multi-hovering capabilities (detection of fingersabove the screen) and edge interaction capa-bilities (detection of fingers on the side ofdevices) to state-of-the-art multi-touch tech-nology without the need for any extra sensorBy combining the power of an integrated cir-cuit with extremely accurate signal-processingsoftware the Sensation platform enables anew world of interactions first with portabledevices such as smartphones and tablets andsoon with any connected surface This z-dimension works up to 5 cm away (10 cm forhand gestures) from the touch screen or pad

Nanosys also won an award in the small-exhibit category for its quantum-dot TVsNanosysrsquos Display Week demonstrationincluded three matched 65-in UHD TVs (Fig 6) Each of the sets used the same colorfilters underlying LEDs and direct-lit back-light structures They were also driven at thesame settings from the same content Theonly difference was in the phosphor used tocreate white light in the backlight Thesewere conventional white LEDs NanosysrsquosQuantum-Dot-Enhancement Film andNanosysrsquo Cadmium-Free Quantum-Dot-Enhancement Film The differences in colorperformance without noticeable brightness

loss were striking Rec2020 color-gamutcoverage ranged from lt60 for the whiteLED set to ~75 for the set with cadmium-free quantum dots to gt90 for the set withquantum dots This demonstration showedthat cadmium-based quantum dots have a significant performance advantage over otherphosphor materials and that Rec2020 isachievable today n

Fig 6 Nanosys featured a side-by-side comparison of televisions using (from left to right)white LEDs cadmium-free quantum dots and quantum dots

Display Week 2016 Innovation Zone (I-Zone)

May 24ndash26 2016The prototypes on display inthe Innovation Zone at DisplayWeek 2016 will be among themost exciting things you see at thisyearrsquos show These exhibits werechosen by the Society for InformationDisplayrsquos I-Zone Committee for theirnovelty quality and potential toenhance and even transform the dis-play industry Programmable shoesinteractive holograms the latesthead-up displays and much morewill not only fire your imaginationbut provide an advance look at manyof the commercial products yoursquoll beusing a few years from nowSID created the I-Zone as a forum forlive demonstrations of emerginginformation- display technologies This special exhibit offers researchers space to demonstrate their proto-types or other hardware demos dur-ing Display Week and encouragesparticipation by small companiesstartups universities governmentlabs and independent research labsDonrsquot miss the 2016 I-Zone takingplace on the show floor at DisplayWeek May 24ndash26I-Zone 2015 Best

Prototype Award Winner

Ubiquitous Energy

VISITINFORMATION

DISPLAY ON-LINEFor daily displayindustry news

wwwinformationdisplayorg

䘀圀䐀最爀愀瀀栀椀挀戀礀吀䤀

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䔀砀栀椀戀椀琀漀爀猀匀瀀漀渀猀漀爀猀㨀䔀洀愀椀氀䨀椀洀䈀甀挀欀氀攀礀愀琀樀戀甀挀欀氀攀礀䀀瀀挀洀㐀挀漀洀漀爀挀愀氀氀　ⴀ㔀　ⴀ㠀㠀倀爀攀猀攀渀琀攀爀猀㨀匀甀戀洀椀琀瀀愀瀀攀爀愀戀猀琀爀愀挀琀猀琀漀䴀愀爀欀䜀漀氀搀昀愀爀戀愀琀洀最漀氀搀昀愀爀戀䀀瀀挀洀㐀挀漀洀戀礀䄀甀最甀猀琀㜀琀栀

吀䠀䔀䔀堀䠀䤀䈀䤀吀䤀伀一㨀䠀攀爀攀礀漀甀氀氀攀渀最愀最攀Ⰰ 猀漀甀爀挀攀Ⰰ 愀渀搀挀漀渀搀甀挀琀瀀爀漀戀氀攀洀猀漀氀瘀椀渀最眀椀琀栀攀砀瀀攀爀琀琀攀挀栀爀攀瀀猀昀爀漀洀搀漀稀攀渀猀漀昀氀攀愀搀椀渀最搀椀猀瀀氀愀礀琀攀挀栀渀漀氀漀最礀瀀爀漀搀甀挀琀Ⰰ 猀攀爀瘀椀挀攀愀渀搀猀漀氀甀琀椀漀渀瀀爀漀瘀椀搀攀爀猀

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䴀䄀刀䬀夀伀唀刀䌀䄀䰀䔀一䐀䄀刀䄀一䐀䨀伀䤀一唀匀䄀吀吀䠀䔀䌀䔀一吀䔀刀伀䘀吀䠀䔀䄀唀吀伀䴀伀吀䤀嘀䔀唀一䤀嘀䔀刀匀䔀

DISPLAY WEEK is all about the presentation and demonstration of visuallystunning displays ndash and this yearrsquos event wasno disappointment Set in the middle of Silicon Valley in the first week of June theshow had an energy that was demonstrablyhigh as evidenced by the 10ndash15 increase inattendance across all events Display Week isfull of opportunities to network learn makedeals and feast your eyes on all the shiny newdisplays Eye candy is a big part of the drawof Display Week ndash with various claims anddemonstrations of the biggest the brightestthe thinnest and the best Complementary toall the hoopla on the exhibit floor and thebiggest draw for engineers and researchersare the opportunities to report on and learnabout the latest technology required to createall that eye candy

One important field of endeavor thattouches all the various visual display tech-nologies is the application of human visionconcepts to the systematic evaluation of display image quality Critical to this applica-tion are the devices and techniques that weuse to measure display optical performanceDisplay technology delivers the photons and

images to the front of the screen (or to the exit pupil) the human vision system (HVS) is there to perceive and appreciate them Measurement device companies create systems to capture and analyze those photonsand images and then deliver objective quanti-ties that engineers use to inform opticaldesigns and monitor manufacturing processes

High Dynamic RangeOne of the more compelling topics arounddisplay image quality this year was highdynamic range (HDR) and extended colorgamut For HDR there was a Monday seminar1an invited paper in the Imaging Technologiesand Applications track2 and a presentation atthe International Committee for DisplayMetrology (ICDM) meeting on Tuesdayevening Dolby Laboratories Inc is a strong proponent of HDR given the companyrsquos long incubation of HDR displayand the Dolby Vision architecture for the capture distribution and display of HDR content Scott Daly and Timo Kunkel deliv-ered a Monday seminar that covered thebasics of HDR display technology and humanvision considerations Daly and Kunkeldescribed how the technology delivers morethan 6 orders of magnitude of luminancedynamic range ndash yielding bright highlightsand good shadow detail simultaneously Oneway to do this is with a dual modulation display In Dolbyrsquos case at least for the consumer market it uses an array of LEDs inthe LCD backlight that is independently

controlled and in synchrony with the image onthe LCD The result is an HDR image createdby a low-resolution luminance-only image onthe backlight that is combined by the high-resolution image on the LCD This type ofbacklight is also known as a local-dimmingbacklight

Dolbyrsquos studies show that 90 of subjectsprefer images rendered with 6+ orders ofmagnitude of luminance dynamic range (fromless than 001 cdm2 to more than 10000cdm2 (see Fig 1)3 Typical LCDs can onlydeliver about 35 orders of magnitude ofdynamic range and a peak luminance of several hundred cdm2 Dolby Vision alsoaccommodates expanded color gamut highbit-depth gray scale (10ndash12 bits per colorchannel) and high frame rate (up to 120 Hz)Luminance dynamic range consistently ranksat the top of the list of those image-qualityparameters that most people prefer followedby color gamut frame rate and resolution Inother words if you want to spend your goldon making your image look better spend it onimproving luminance dynamic range

HDR and wide color gamut enable greatercreative choices by making a larger color volume available However care must betaken throughout the image capture transfor-mation color grading and mastering processes to preserve luminance and colorinformation so that the intended image can bepresented in either cinema or video contextsJames L Helman of MovieLabs delivered aninvited paper2 describing the background and

Image Quality and Metrology Display technology delivers the photons to the front of the screen the human vision systemdetects the photons and perceives an image Measurement devices capture and analyze imagecharacteristics and deliver objective quantities that engineers use to inform optical designsand monitor manufacturing processes

by Tom Fiske

Tom Fiske is currently a consultant specializ-ing in display technology image quality andoptical metrology He has been on the techni-cal staff at Qualcomm Rockwell CollinsPhilips Electronics dpiX LLC and XeroxPARC He can be reached at tgfiskegmailcom

image quality and metrology review

ID Fiske p12-15_Layout 1 9132015 113 PM Page 12

reasoning behind some of the standards andarchitectures in the capture mastering andrendering tasks that take advantage of HDROne process this paper focused on is the adop-tion and standardization of a perceptuallybased gray level to absolute luminance transfercurve to replace the traditional gamma curvesused since the early days of video productionA 12-bit gray ramp as embodied in SMPTEST 20842014 results in no gray-level bandingartifacts and handles the wider primaries proposed for use in BT2020

Helman reported that the Academy ofMotion Picture Arts and Sciences has devel-oped an advanced color system and digitalframework called the Academy Color EncodingSystem (ACES) ACES promises to simplifyand improve the handling of multiple camerasfilms and mastering display devices throughthe definition of formats and standard colortransforms This will help manage the burdenof adding and preserving HDR to content as itmakes its way to various display devicesWhile it is still early the infrastructure is

being put in place to deliver HDR-enabledcontent in wide distribution The goal is torealize a video system that delivers imagesbelow perceptual thresholds with a full-gamut-color system that matches the capacityof the HVS

ICDM Tackles Contrast and DynamicRangeAt the ICDM meeting on Tuesday evening ofDisplay Week Daly and Darin Perrigoreviewed various ways that luminance contrast and dynamic range have traditionallybeen characterized and reported Perrigorsquospresentation focused on problematic issueswhen characterizing contrast in front-projectorsystems Daly suggested extensions of current methods from the Information DisplayMeasurements Standard (IDMS)4 that willgive more relevant and useful informationSequential contrast ratio (luminance of full-screen white divided by luminance of full-screen black IDMS Section 510) is not adequate to fully describe the dynamic-range

behavior of modern displays This is espe-cially true in regards to emissive displays(eg OLEDs) for which the black state is toodim to measure accurately as well as displaysthat use global or local backlight dimmingANSI (aka black and white checkerboard)contrast (IDMS 526) another populardynamic-range metric has an average lumi-nance that is not representative of mostimagery (too high) overestimates internal display flare and underestimates perceivedcontrast capability

Daly reviewed several other extant methodsfor characterizing contrast including full-white-signal contrast (IDMS 591) peak contrast (IDMS 511) starfield contrast(IDMS 512) and corner-box contrast (IDMS513) He concluded his remarks with adescription of an extension of the corner-boxcontrast method by adding measurements ofimages in which the position and gray level ofthe bright boxes are varied These have theadvantage of including in the characterizationsome of the beneficial effects from local-

Fig 1 Studies from Dolby show that 90 of subjects prefer images rendered with 6+ orders of magnitude of luminance dynamic range3 Imagecourtesy Scott Daly Dolby Laboratories Inc

dimming displays in a relevant and realisticway He also mentioned some potential waysto account for the spatio-temporal characteristics

of the HVS High-spatial-frequency-contrastdetection is limited by glare and the MTF ofthe human vision system5

Extended Color Gamuts Another aspect of adding to the color-volumecapability of displays is extending the colorgamut by making the red green and bluecolor primaries more saturated The SIDexhibit floor offered examples of one of themain methods for realizing this technologyThe two most common methods for achievingextended-color-gamut displays are laser (orlaserhybrid) projection or LCDs illuminatedby backlights using blue LEDs and quantum-dot technology Two of the most prominentimplementations of quantum-dot backlightsare from Nanosys and QD Vision Both methods use blue LEDs as the light source to illuminate quantum dots that down-convertsome of the blue light to green and red lightThe result is narrow spectral bands of bluelight (from the LEDs) and green and red light(from the quantum dots) The narrow spectralbandwidth of the resulting light ndash puttingspectral power only in the red green and blue portions of the backlight spectra ndash is what enables the wider primaries and extendedcolor gamut The Nanosys approach uses ablue-LED-backlit light guide coupled with aquantum-dot-impregnated film (supplied by3M) to deliver the uniformly distributed bluegreen and red light to the back of the LCDpanel The QD Vision approach is exclusivelyan edge-lit design The light from a lineararray of blue LEDs is coupled with a strip thatcontains quantum dots and the resulting bluegreen and red light is uniformly distributed tothe back of the LCD panel via a light guideThe QD Vision method has a cost advantagebut may be somewhat less efficient than theNanosys3M approach Nanosys claims betterefficiency due to effective light recycling andits method is compatible with HDR displaysbecause it can more easily accommodate alocal-dimming backlight

QD Vision has announced that its Color IQtechnology is in sets from Philips HisenseTCL and Konka Nanosys quantum-dot-enhanced sets are also available from Samsung and AUO Both quantum-dot companies were well represented on the Display Week exhibit floor with stunningdemonstration sets The images in each bootheffectively highlighted the visual power ofwide-color-gamut displays Nanosys won aBest-in-Show award (for the second year in arow) It was also the only booth at the exhibitthat featured performances by acrobats () ndashsee Fig 2

Fig 2 The Nanosys booth at Display Week featured three displays (from left to right a conven-tional LCD with quantum dots with Cd-free quantum dots) ndash and acrobats Image courtesyNanosys Inc

Fig 3 Photo Research displayed its Tru-Image 2D Imaging Colorimeter Image courtesy TomFiske

The exhibition also highlighted severaladvances on the metrology hardware frontOne example is the new Tru-Image series of2D imaging colorimeters (Fig 3) from PhotoResearch These instruments feature a thermoelectrically cooled 8- or 16-MpixelCCD with a high-speed CIE color wheelThey come with Windows-based VideoWin 3 Pro software to control the instrument andanalyze the data Measuring capabilitiesinclude 2D-based luminance chromaticitycorrelated color temperature and CIELABanalysis

Radiant Vision Systems showed off its lineof automated-visual-inspection solutions Thecompany has been working on fielding con-figurations that reduce takt time for examplewith its ProMetric I series imaging colorimetercoupled with multiple spectrometers for test-ing smartphone displays Their lineup alsoincludes imaging spheres and imaginggoniometers for angular measurements

At the Gamma Scientific booth we saw thecompanyrsquos Robotic Display MeasurementSystem that combines a 6-axis robot and high-performance spectroradiometers for fastaccurate display measurements (Fig 4)

Gamma Scientific fields a large array ofoptical measurement tools including spec-

trometers integrating spheres calibrated lightsources goniophotometers and LED testers

Display Week is an important venue for thepresentation of new display technologies andapplications A significant goal of displaytechnology is the continuous improvement of front-of-screen image quality The chiefmethod used to monitor progress and verifyimage-quality goals is by using proper displayoptical-measurement methodologies and toolsDisplay Week 2015 highlighted the advance-ments of HDR and extended color gamut andhow the standards community is beginning toaddress these features The exhibit featuredexamples of extended-gamut displays and several new display measurement toolsdesigned to aid the engineer technologist andmanufacturer in the pursuit of image-qualityimprovement

References1S Daly and T Kunkel Seminar M-2 ldquoHigh-Dynamic-Range Imaging and Displaysrdquo SIDSeminar Lecture Notes (2015)2J L Helman ldquoDelivering High Dynamic Range Video to Consumer Devicesrdquo SID SymposiumDigest of Technical Papers 46 (2015)3S Daly T Kunkel X Sun S Farrell and P Crum ldquoViewer Preferences for Shadow

Diffuse Specular and Emissive LuminanceLimits of High Dynamic Range DisplaysrdquoSID Symposium Digest of Technical Papers44 (2013)4International Committee for Display Metrol-ogy (ICDM) Information Display Measure-ments Standard (IDMS) ver 103 (2012)httpwwwicdm-sidorg5E H A Langendijk and M Hammer ldquoCon-trast Requirements for OLEDs and LCDsBased on Human Eye Glarerdquo SID Interna-tional Digest of Technical Papers 41 (2010)

n

Fig 4 This Robotic Display Measurement System from Gamma Scientific featured a six-axisrobot (at right) Image courtesy Tom Fiske

Submit Your News ReleasesPlease send all press releases and new productannouncements to

Jenny DonelanInformation Display Magazine411 Lafayette Street Suite 201

New York NY 10003Fax 2124605460

e-mail jdonelanpcm411com

J O I N S I DWe invite you to join SID to participate in shaping the future development of

bull Display technologies and display-related products

bull Materials and components for displays and display applications

bull Manufacturing processes and equipment

bull New markets and applications

In every specialty you will find SIDmembers as leading contributors totheir profession

httpwwwsidorgMembershipaspx

WITHOUT new materials and new manufacturing processes progress in displaytechnology is limited to evolutionary rather than revolutionary changes On the show floor at Display Week this year we saw three majorcategories of new and evolving materialsdisplay glass flexible transparent conductorsand quantum-dot products In addition bothon and off the show floor Sharp was talkingmuch more than previously about how it hasimplemented gate drivers on a displayrsquos imagearea to create its attention-grabbing free-formdisplays Off the show floor there was con-siderable discussion about micro-LEDs Candice Brown-Elliott Nouvoyance CEO andcreator of the Pentile matrix configurationwidely used in Samsung OLED displays saidthis was the only truly disruptive technologyshe saw at Display Week this year And therewere additional interesting materials develop-ments that did not fit into any of these categories

GlassThe three leading manufacturers of display glass ndash Corning Asahi Glass Company (AGC) and Nippon Electric Glass (NEG) ndash along with glass fabricator Cat-i Glass Manufacturing(Elgin Illinois) were all on the show floorAlso in the exhibit hall were LCD re-sizer

Tannas Electronic Displays (Orange Califor-nia) and Litemax Technology (Fremont Cali-fornia) which resizes LCDs and fabricates custom-sized signs and monitors using its resized panels In an aisle I also ran into Larry and Like Linden of glass-cutter TLC Interna-tional (Phoenix Arizona) I have known TLCas a scriber of straight curved and circularlines in glass but I did not know until thismeeting that it also cuts complete LCDs

Corning was showing several technologiesincluding its Iris Glass designed to replacepolymer light-guide plates in television displays its flexible Willow glass two typesof Gorilla Glass and NXT Glass its ldquonext-generationrdquo product Each of these varieties isdesigned to fit specific design needs althoughin some cases their capabilities overlap

According to Corning an Iris light-guideplate ldquoeliminates space and components features excellent transmission and enablesthinner brighter TVs with accurate colorsrdquoAlso on display was the second generation of100-mm-thick Willow glass on a carrier ofconventional display glass This allows theglass to be processed on a conventional manu-facturing line and then separated from the carrier The display is now on a very flexiblesheet of glass that can be rolled to a rathertight radius while the expensive carrier can beresurfaced and re-used If used as the substratefor a flexible OLED display the Willow glassblocks moisture and oxygen unlike polymersubstrates

Corning had an extensive display of GorillaGlass for automotive demonstrations includingldquocold formrdquo in which a flat piece of Gorilla

Glass is bent to fit the application and piecesthat are hot-formed for applications requiring3D surfaces or a localized bend ndash bends thatvary in curvature across the sheet (Fig 1)

Gorilla Glass 4 was announced at CESCorning reps were happy to explain that it has been engineered with increased fracture resist-ance if a phone (for instance) is dropped on the display side while Gorilla Glass 3 is engineered for maximum scratch resistance and scratch concealment Since the two versions optimize different characteristicsboth will be produced Corning discoveredthat dropping a Gorilla 3 phone face down ona slightly rough surface such as concrete asphalt or sandpaper is more likely to produce fracture than a similar drop onto a smooth surface such as hardwood granite or steelThe design of Gorilla 4 resolves that issuesays Corning

Lotus NXT Glass Corningrsquos next-generationdisplay glass is described by the company asldquostable glass for high-performance displaysrdquoUnder typical display processing this glassexhibits a significantly lower ldquototal pitch variationrdquo ndash less variation in the pitch of theTFT array relative to the color-filter array A glass poster showed the improvement to besignificant Lotus NXT is available in thick-nesses as low as 04 mm

In its booth Asahi Glass Company (AGC)featured Dragontrail its competitor for GorillaGlass New was a flexible version calledDragontrail X (Fig 2) AGC also showedsoda-lime glass as thin as 023 mm andldquoSpoolrdquo an ultra-thin developmental glassthat is 005 mm thick Two or three years ago

Display Materials and Processes In addition to three major categories of new and evolving display materials ndash display glassflexible transparent conductors and quantum dots ndash a potentially disruptive material-and-process combination appeared at Display Week this year

by Ken Werner

Ken Werner is Principal of Nutmeg Consultantsspecializing in the display industry manufac-turing technology and applications including mobile devices and television He consults for attorneys investment analysts and companies using displays in their products He can be reached at kwernernutmegconsultantscom

display materials and processes review

ID Werner p16-23_Layout 1 9132015 123 PM Page 16

at Display Week AGC showed its own version of thin glass on a carrier along thelines of Corningrsquos Willow but I did not see itthis year

AGC also showed its new ldquoGlass Plusrdquoglass-resin composite component Glass Plusis a display cover glass (which may contain atouch-panel sensor) bonded to a surroundingpolymer frame that can be flush to the glasson one or both sides The component cantherefore do away with the separate frame orbezel that often surrounds the cover glassdecreasing product thickness and removingboth a component and an assembly step

Nippon Electric Glass (NEG) which wonan award for best medium-sized exhibit on theshow floor this year featured its own 02-mmglass called G-Leaf NEGrsquos Ted Shimizuhighlighted G-Leafrsquos roll-to-roll processingand possible use as a flexible OLED substratewith inherent barrier qualities He also mentioned heat shields for laboratory andindustrial workers as a possible applicationthat would leverage G-Leafrsquos impressivetransparency

When it comes to ultra-thin glass glass-makers are ahead of their display-making customers Rollable display glass is availablenow or will soon be available from the threeleading fabricators but display-makers havenot yet developed the processes needed tomake use of it LCD manufacturers may notfeel justified in spending a lot of money tomake major changes to plants and processingto incorporate roll-to-roll especially sincethere are difficult problems to solve One of these is maintaining cell thickness when a flexible LCD is rolled to even moderateradiuses (Merck KGaA thinks it has a solu-tion for this problem and is looking for devel-opment partners You will find more detailslater in this article)

A nearer-term application of ultra-thin glassis OLED displays even though this applica-tion requires a transition to printed OLEDfront planes That has been a subject of serious RampD for years At the beginning ofDisplay Week DuPont Displays and Kateevaannounced they would collaborate to optimizeink-jet printing for the mass production ofOLED TVs ldquoWith Kateeva and DuPont combining their considerable expertise in ink-jet printing and OLED materials the industryis poised to take a significant step forward inachieving low-cost mass production of OLEDTVrdquo said Steven Van Slyke CTO at Kateeva

From another source that might sound likestandard commercial puffery From VanSlyke (co-inventor of the practical OLED display) it deserves to be taken seriously

Quantum DotsA lot of the conversation about quantum dotsat Display Week this year revolved around theEuropean Commissionrsquos rejection of its owntechnical committeersquos recommendation thatcadmium-based quantum dots continue to beexempt from prohibition because cadmium ison the European list of dangerous substances

Initially this generated some angst in thecadmium contingent and some jubilation inthe non-cadmium (mostly indium phosphide)crowd But a consensus soon emerged thatthe ECrsquos rejection was based on one minortechnical and one procedural matter and thatthe technical committee would certainly

correct the minor issues after which theexemption would be continued EC exemp-tions are often based on there being no alter-native solution available so the issue revolvedaround the current availability of indiumphosphide However indium has also beenadded to the EUrsquos list of hazardous substancesIt was generally regarded as irrelevant to theregulators that neither cadmium nor indium isbiologically available when encased in aquantum-dot shell

Nanosys which won an award from SIDfor best small exhibit at the show had threeside-by-side TVs that clearly showed whyindium-phosphide quantum dots (QDs) are apoor substitute for cadmium The typical conventional LCD TV with white-LED back-lighting in the Nanosys booth had a measuredcolor gamut of less than 60 of Rec2020 aluminance of 500 nits and a power consump-

Fig 1 Corning Gorilla Glass can be formed with a ldquolocal bendrdquo for automotive applicationsPhoto courtesy Ken Werner

tion of 130 W The same model of TV modi-fied with blue LEDs and a cadmium QD sheetin the backlight measured greater than 90 ofRec2020 400 nits and a power consumptionof 130 W (with the original color-filter array)(Fig 3) And another example of the samemodel TV with an indium-phosphide QDsheet measured about 75 of Rec2020 350nits and 130 W Clearly if the goal is to getclose to Rec2020 indium phosphide is notthe way to go Subjectively the differencebetween the cadmium QD-enhanced TV andthe standard model was dramatic The differ-ence between the indium-phosphide-enhancedset and the standard one was visible but suffi-

ciently subtle that consumers might not bestrongly motivated to pay a premium for it

Nanosys Corporate Communications Manager Jeff Yurek wanted me to know thatNanosys has now reached a level of manufac-turing volume such that the EPA required it tosubmit a pre-manufacturing notice which wasaccepted He also announced a follow-oninvestment from Samsung Venture InvestmentCorporation The new funds will be used toexpand production capacity as demandincreases

Also at Display Week Nanosys partner 3MDisplay Materials and Systems Divisionshowcased LCDs in several sizes with color

gamuts of up to 937 of the Rec2020 colorgamut Among the demos was a 4K monitorwith 937 Rec2020 which demonstrated as the booth signage read ldquoone of the largestknown color gamuts in an otherwise commer-cially available 4K LCD monitorrdquo

QD Vision was exhibiting available commercial products using its IQ Color linearQD element Among these were a Philips 29-in monitor a TCL 65-in TV and aHisense 65-in curved TV This is the firstcurved TV said CMO John Volkmann and ituses one edge light and one IQ Color elementon each of the left and right edges

I asked Volkmann if he was concerned thatan increasing percentage of TV sets are usingdirect backlighting for local-area dimmingand therefore cannot use QD Visionrsquos lineararray His answer ldquoThere will be a lot ofedge-lit TVs made for the foreseeable futurerdquoHe also said the company was looking at otherform factors As previously stated the company is working on a QD-on-chip approach and is closer than its competitors There wasa 94 Rec2020 demo in the booth To gethigher than that Volkmann said wide-gamutcolor-filter arrays as well as high-quality QDs(such as QD Visionrsquos) are required Volkmannwas confident that cadmium would remainlegal in the EU and did not mention any fall-back materials for QD Vision

If Nanosys 3M and QD Vision are amongthe leading QD companies Quantum MaterialsCorp (San Marcos Texas) is one of the hope-fuls Although not exhibiting at DisplayWeek QMC announced in a June 1 pressrelease that it had ldquolaunched their new QDXclass of high-stability cadmium-free quantumdotshelliprdquo The release continued ldquoQDX quantum dots have been tested to withstandheat resistance to 150degC for 4 hours with nooxidation performance degradation in anopen-air environmentrdquo When I asked himQMC PR person Art Lamstein told me thecompany is in a ldquopre-revenuerdquo stage In addi-tion to the companyrsquos original cadmium-basedquantum tetrapods based on a Rice Universitypatent QMC is now also making indium-phosphide dots based on a Bayer patent thecompany purchased in 2014

Nanoco (Manchester UK) was not on theshow floor but I spoke briefly with COOKeith Wiggins and Business Development VPSteve Reinhard Since Nanoco has for sometime emphasized that its QDs are free of notonly cadmium but also of other heavy metals

Fig 2 AGCrsquos Dragontrail X is a flexible version of its Dragontrail product which competes with Corningrsquos Gorilla Glass Photo courtesy Ken Werner

the company has been almost gleeful in wel-coming the European Parliamentrsquos decision toturn down the RoHS exemption for cadmiumdespite its approval by the technical commit-tee However as mentioned above the major-ity opinion is that this potential gift to Nanocois likely to be short-lived As is well knownNanoco has licensed its technology to DowChemical for volume manufacturing

Transparent Flexible ConductorsTransparent flexible conductors (TFCs) provide added value based on their thinnesslight weight and ruggedness even when theyare being applied to displays with rigid substrates Now that flexible displays areentering the marketplace in significant numbers that value becomes even more pronounced

TFCs compete on a combination of cost(low is good) sheet resistance (measured inohms per square low is good) transmittanceor transparency (high is good) lack of color-ation (none is good) haze (the lower the betterfor most but not all applications) degree offlexibility (measured by the diameter of amandrel around which the film can be bent)and maintenance of sheet resistance withrepeated flexing

The first technologies in the market werefabricated metal matrices and silver nanowire(AgNW) inks AgNW inks have taken thelead because metal matrices have a regularpitch that produces moireacute interference withthe pitch of the pixels unless the matrix isespecially designed for each display and theirrelatively large feature size means they cannotbe used with displays having very fine pixelpitches AgNW patterns are random and canbe used with virtually any pixel pitch with thesilver wires from some makers now so finethat they produce very little haze in brightsunlight Cambrios is the current AgNWleader

However as we saw at Display Week other ways to play the game have alreadyescaped from university labs and corporateskunkworks Here in no particular order arethe entries that appeared on the show floor

Richard Jansen VP of Sales and Marketingat SouthWest NanoTechnologies (SWeNTNorman Oklahoma) said his company usesboth AgNW and carbon nanotubes (CNTs) intwo layers The CNTs are screen-printed ontop of the AgNWs where they serve as a patterning mask The unprotected AgNWs are

washed away with water and then reclaimedWhen AgNWs are used by themselves andadhered to the underlying film Jansen saidthey require laser patterning or photolithogra-phy Thus SWeNT offers an easier andquicker patterning process The company isseveral months away from customer sampling

Canatu Oy (Helsinki Finland) uses carbonnanobuds for its conducting medium Thesebudlike structures appear on the exterior wallsof CNTs when they are grown said Canatumarketing and sales VP Erkki Soininen butCanatu forms its nanobuds directly throughthe reaction of gasses The nanobuds saidSoininen literally fall out of the reactinggasses onto a film in a roll-to-roll processThere is enough adhesion between the budsand the film so the product can be shipped inthis form The customer patterns the film andadds an overcoat and any other films neededfor his application The Canatu process produces TFCs with sheet resistances as lowas 100 Ωq at 95 transparency Canatu hasjust announced its first design win a flexibleconsumer product What product Soininencanrsquot say Not yet

Kelly Ingham COO of Cima NanoTech (St Paul Minnesota and Singapore) told methe company is currently making a major

transition to manufacturing and is ramping uphigh-volume film production in China CimaNanTech spent 10 years in RampD mode so thisis a very significant change Ingham and twoother members of the strong senior manage-ment team are former 3M employees and presumably familiar with high-volume films

The companyrsquos SANTE technology appliesproprietary nanoparticles on PET or otherpolymer film in a wet roll-to-roll processThe nanoparticles then self-assemble into arandom metal mesh with 3ndash6-microm conductorsThe process can produce films with a 25-Ωqsheet resistance at 87 transmissivity (includ-ing the PET) The SANTErsquos ldquoshadingrdquo ndash thetransmissivity loss caused by the metal meshalone ndash is only part of the total loss NanoTechrsquos first app is a game table with 10-finger touchfrom a US company in which the large dis-play size and requirement for 6-msec responsetime demands very low sheet resistance Thetechnology can go as low as 10 Ωq for largesizes

At Display Week Stanford spin-outC3nano (Hayward California) culminated astring of major announcements this year byintroducing its highly flexible ActiveGardhardcoat for its AgNW TFC product C3nanodeposits an ink containing silver nanowires

Fig 3 Shown is the cadmium quantum-dot-enhanced example from the comparison shown inNanosysrsquos prize-winning booth The demo made it very clear that cadmium quantum dotsdeliver a much greater color gamut than indium-phosphide dots Photo courtesy Ken Werner

that overlap each other in a loose web Thewire web is open enough so light can passthrough but dense enough to provide good conductivity C3nanorsquos wrinkle is ldquoNanogluerdquo technology a catalyst-mediated process thatcauses the AgNWs to fuse where they crossThis results in greater conductivity for a givenwire diameter which can be used to deliverlower sheet resistance less haze or a combi-nation of the two said CEO Cliff Morris

These are the TCFs that were on the showfloor Still in laboratories are carbon nano-tubes graphene and who knows what elseFor a category often thought of as simplyldquoITO replacementsrdquo TCFs have become veryinteresting indeed

Off the Show FloorIt took five contributors to produce the report-ing for Information Displayrsquos coverage of Dis-play Week and we did not come close toseeing and hearing everything There weremany many technical and business presenta-

tions at Display Week some of quite generalinterest some by specialists for a handful oftheir fellow specialists Here are short sum-maries of a very few materials-and-process-oriented presentations I was smart enough toseek out or lucky enough to stumble upon

For some time Sharp has been showingexamples of its ldquofree-formrdquo displays whichdo both the ldquorowrdquo and ldquocolumnrdquo drivingthrough one edge of the display leaving therest of the display to be cut in curves or otherunusual shapes (Fig 4) But until this DisplayWeek Sharp had not been willing to describein detail how it distributed the gate driversthroughout the display so that conventionalrow drivers mounted on a vertical displayedge are not necessary

In the Sharp booth Automotive MarketingDirector for Display Products Thomas Spearsdid his best to explain the situation but it washard for him to do so in any detail amidst thecut and thrust on the show floor More detailwas available from the invited paper by

Hidefumi Yoshida and 13 colleagues fromSharp in Nara Japan The paper ldquoFlexibleFlat-Panel-Display Designs with Gate DriverCircuits Integrated within the Pixel Areardquodescribed Sharprsquos truly clever approach

Yoshida and colleagues began with a well-known method gate-driver monolithiccircuitry (GDM) With GDM the shift regis-ters and output transistors of the gate driversare deposited on the vertical edge of the display at the same time as the switching transistors are fabricated This is an alterna-tive to the more conventional approach ofusing ICs for the gate-driver circuitry SinceGDM circuitry can occupy significant realestate at the vertical edge of the display especially when implemented in amorphoussilicon it requires a wide bezel which is notcompatible with current display preferences orwith gracefully curved display contours

Here is where Sharprsquos cleverness comesinto play First instead of putting the GDMcircuitry on the vertical edge(s) of the displaySharp locates it in one or more verticalldquobandsrdquo within the display area (Fig 5) Irsquoveput ldquobandsrdquo in quotes because Sharp has donefar more than simply shifting the left-edge circuitry into the image area Sharp dispersesthe transistors of the GDM circuitry so indi-vidual transistors are located at individualpixel locations and interconnected via addi-tional surface connections and a large numberof through holes in the display Thus the gate-driver control signals enter through the bottomedge of the display which is also where thesource drive ICs are located The gate signalstravel from the dispersed GDM circuits hori-zontally to the pixels but entirely within theimage area This allows the left right and topedges of the display to have very thin bezelswhich can be shaped with great freedomSharp has widely shown a triple curve that isappropriate for the tachometer speedometerand combined temperaturegas gauge in a primary automotive instrument display Thisis a significant innovation in display architec-ture that is as Yoshida et al carefully note just as applicable to OLED displays as toLCDs

Dow Corningrsquos EA-4600 HM RTV hot-melt adhesive was initially developed as analternative to double-sided tape in the assemblyof cell phones and other electronic devices Inthis role it can be 20 of the cost of DS tapein large-volume applications But because thematerial requires dispensing equipment that

Fig 4 This recent demo of Sharprsquos ldquofree-formrdquo LCD technology has a curved top and almostno bezel on the top three sides The display incorporated touch on the outside edges of the dis-play not the surface Photo courtesy Ken Werner

costs in the vicinity of $100000 it takes highvolumes for the much lower material cost todeliver maximum savings

In a poster paper entitled ldquoSilicon Hot-MeltAdhesive Providing Protection Waterproofingand Reworkability for Precision Assembly ofElectronic Devicesrdquo Ryan Schneider GlennGordon and colleagues from Dow Corningexplained that one advantage of the silicon hotmelt is that it can be used to make to makebeads of 05 mm or less when for examplemaking a peripheral seal on cell-phone win-dow glass where maximum screen area iscrucial It is said Gordon impossible to cutDS tape that finely

Although the original conception was to usethe hot melt as an adhesive for assembly ifyou deposit a peripheral bead on only one surface and allow it to cure it forms a gasketthat can be used to provide water- and dust-proofing for a snap-on cover ndash and the covercan be removed and re-snapped indefinitelywhile still retaining its water-proofing charac-teristics This approach was used to water-proof the back cover of a recent popularsmartphone model Although Schneider andGordon would not identify the model in ques-tion reliable industry sources tell me it wasthe Samsung Galaxy S5 (Fig 6) Dow Corningis talking to other manufacturers about adopt-ing the technique

Merck KGaA (Darmstadt Germany)offered a substantial number of technical presentations Two were particularly interestingIn an invited paper Merckrsquos Martin Engel andcolleagues discussed the companyrsquos ultra-

bright fringe-field-switching (UB-FFS) for-mulation which provides 15 more transmit-tance than standard FFS The product is currently available but various parameters ndashincluding switching speed and reliability ndashstill need to be improved said Engel

Engel noted that in both UB-FFS and FFStransmittance depends on the polarity of theapplied voltage and this produces flickerThe reason is not fully understood but someformulations can reduce the flickerswitching-speed trade-off

In the QampA FacebookOculus VR execu-tive Mary Lou Jepsen asked if the diffractionseen at the edge of the fringe field is any less than in UB-FFS Engel speculated thatthere would be less diffraction because thereis less tilt at the edge of the fringe with UB-FFS

In ldquoOpening the Door to New LCD Appli-cations via Polymer Wallsrdquo another invitedpaper from Merck KGaA Nils Greinert andhis colleagues revealed a practical way ofmaking LCDs with internal polymer wallsCurrently most of the interest in flexible displays is focused on OLED displays whichare amenable to being bent if they are fabri-cated on a flexible substrate Itrsquos harder withLCDs which depend on a precisely main-tained cell gap for proper operation Bendinga conventional LCD decreases the cell gap(Current curved LCD TVs side-step this problem by bending the LCD so slightly thatcell-gap reduction and substrate misalignmentremain insignificant)

The problem could be solved by fabricatingwalls between the flexible substrates (and inbetween the pixels) to stabilize the cell gapwhen the display is bent This is not a newidea NHK showed a simple ferroelectricLCD with walls in the early 2000s and theMerck authors cite other early efforts Butthere was not a process for fabricating thewalls that was efficient and compatible with

Fig 5 At right a conventional display has gate-driver circuits located in the bezel area At leftthe Sharp display has gate drivers integrated within the pixel area (Graphics Yoshida et al)

Fig 6 Dow Corningrsquos EA-4600 HM RTV hot-melt adhesive (presumably) forms this waterproofgasket in the authorrsquos Samsung Galaxy S5 phone Photo courtesy Ken Werner

standard LCD fabrication techniques That isthe problem Merck KGaA has solved

Greinert and his colleagues mix polymerprecursors together with the LC host andhomogenize the mixture by heating it abovethe liquid-crystal clearing point The authorscall the resulting mixture a ldquopolymer wall LCmixturerdquo The mixture is enclosed betweenthe two substrates and UV-irradiated througha photomask The walls form and the LC hostsettles down to its expected orientation and tiltangle Remarkably if the proportion of precursor to LC material is chosen properlyall of the monomers are incorporated into thepolymer walls and the LC characteristics arevery very close to what they are in a conven-tional process (Fig 7)

The authors note that ldquototal monomer concentration photomask cell and UV equip-ment have to be considered and optimized inorder to produce the desired polymer-wall pat-ternrdquo However they also say ldquoWe havefound that commercially available monomersdo not satisfy the simultaneous requirementsof good mask reproduction and mechanicalstabilityrdquo Merck KGaA is currently developingtailor-made monomers to solve this problem

Following the paper Robert Miller (SeniorBusiness Manager LC and Advanced Tech-nologies at Merckrsquos US subsidiary EMD Per-formance Materials) told me ldquoWe feel wehave demonstrated the effectiveness of thebasic materials and process and we are nowlooking for development partnersrdquo

Last but Certainly Not Least Micro-LEDsJohn Rogers (a professor at the University of

Illinois and co-founder of and technologyadvisor to X-Celeprint) presented a Mondayseminar entitled ldquoMicroscale LEDs for Multi-functional Display Systemsrdquo You may recallthat this is the technology Candice Brown-Elliott called disruptive Microscale LEDs (ormicro-LEDs or micro-ILEDs) were not wellknown outside the relatively small communityof people who work on them before Appleacquired LuxVue last year at which point amuch wider community started scrambling tolearn about them

It would be very attractive to make phonetablet and TV displays from inorganic LEDsbut there has been no inexpensive way to

assemble LED chips into dense RGB arraysIf it were possible such displays could be several times as efficient as OLEDs and havelonger lifetimes

What Rogers and colleagues along with ahandful of micro-LED companies havelearned to do is to initiate the epitaxial growthof AlInGaP LEDs on recyclable GaAs wafersRogers described a process for making multiplelayers of LEDs with sacrificial layers inbetween that allow the layers to be lifted offThatrsquos impressive but solves only half theproblem If we went no farther we couldmake no more than wafer-sized displays (Fig 8)

The second part of the solution was coveredby Chris Bower CTO of X-Celeprint (CorkIreland) who described the companyrsquos tech-nology for performing transfer printing of thechips using elastomeric stamps utilizing peel-rate-dependent adhesion To oversimplifyshamelessly if you place the stamp on thelayer of chips and peel it off quickly the chipsadhere to the stamps By impressing thestamp on the target substrate and peeling it off slowly the chips adhere to the target Thisis also impressive but it still does not createLED arrays any larger than the original lattice-matched array

As it turns out it is relatively simple toimpose patterns on the stamps that result inpicking up every 10th 20th or nth LEDbefore depositing them on the substrate In this

Fig 7 (a) The ldquowall LCrdquo mixture consists of the LC host (blue rods) and polymer precursors(red dots) (b) The mixture is deposited in the display and exposed to UV radiation through aphotomask which results in polymerization-induced phase separation (c) Polymer walls formin the irradiated regions The liquid-crystalline phase is restored and equally important hasaligned itself with the polyimide layer (Graphic Greinert et al)

Fig 8 This diagram shows a multilayered epitaxial lift-off (Graphic John Rogers)

way you can go from the dense array of theoriginal wafer to a sparse array on the targetsubstrate In principle this allows you tomake micro-ILED displays of virtually any diago-nal Bower said that X-Celeprint has made150-mm stamps Making larger ones is just amatter of engineering he said not science

Now obviously if you can transfer-print u-ILEDs you can also transfer-print CMOSswitching circuits and no longer worry aboutthe instability issues of a-Si and IGZO TFTsor the scalability issues of LTPS In fact youcan transfer-print many types of ldquochipletsrdquoand even assemble them in three-dimensionalstructures Displays are only one applicationof the technology

Some experts have speculated that the firstmicro-ILED display we see in a commercial productmay come from LuxVue and appear in anApple iWatch as early as next year While

that may be a touch on the early side it willbe interesting to see if and when the technologystarts to make inroads Is it possible that micro-ILED not OLED will become the universaldisplay that replaces the LCD That is aquestion that should be commanding the atten-tion of all of us in the display community

We led off this article by saying new materials and new manufacturing processesare basic to major display developments Thatbecomes very clear in the context of micro-ILEDand transfer-printing technology n

Display Week 2016May 22ndash27 2016

Submit Your News ReleasesPlease send all press releases and newproduct announcements toJenny DonelanInformation Display Magazine411 Lafayette Street Suite 201New York NY 10003Fax 2124605460e-mail jdonelanpcm411com

For daily display industry news visit

AT THIS YEARrsquoS Display Week in SanJose California we saw a growing renais-sance of some tried-and-true display technolo-gies ndash including and especially new-usemodels for microdisplays in both the consumer-wearable and automotive marketsthe latter in the form of head-up displays(HUDs) These use models included applica-tions created by size and weight break-throughs and lower power requirements andenhanced in part by new semiconductormaterial compounds ndash all discussed belowThis technology trend even goes beyond displays with some microdisplay companiesnow targeting industrial optical inspection andsensing in very-high-tolerance manufacturingSome companies are now obtaining more thanhalf of their revenue from non-display-relatedapplications

Near-to-eye (NTE) and 3D displays are alsoexperiencing a resurgence particularly whenempowered by eye-tracking sensors and algorithms that boost system understanding ofldquouser intentrdquo These technologies are beingused to help generate autostereoscopic 3Dsolutions and light-field holographic displaysthat begin to push the boundaries of currentdisplay capabilities

Meanwhile in the HUD space we discov-ered new film technologies that transformsimple glass (in the car and elsewhere) intonext-generation displays that when combinedwith the latest sensor technology can bring to

reality visions of a display future onlydreamed about in sci-fi film and literature justa few short years back Itrsquos exciting to seethese older technologies rising again withsome new twists

NTE Technology for Wearables Wearables are one of the fastest growing markets in the microdisplay category This

fact is not lost on headset-maker Kopin acompany that was in the wearable-displaybusiness before it was even called that (seeFig 1 for some examples of its applicationsfor various devices) Kopinrsquos Dr ErnestoMartinez-Villalpando presented at DisplayWeekrsquos IHS-sponsored Business Conferenceexplaining how augmenting the human visualsystem with HUD or NTE devices offers the

Microdisplays Near-to-Eye and 3D New display technologies including some new twists on tried-and-true display technologiesare helping displays integrate ever more seamlessly with the devices we use every day

by Steve Sechrist

Steve Sechrist is a display-industry analystand contributing editor to Information Display magazine He can be reached atsechristuclaedu or by cell at 503704-2578

microdisplays near-to-eye 3D review

Fig 1 Kopin demonstrated a table-top of display applications for its small display components

ID Sechrist p24-28_Layout 1 9132015 148 PM Page 24

opportunity to move beyond simple data inter-faces such as display monitors or smart-phones Much like bionic prosthetic limbsHUD and NTE technology begin to addressthe possibility of true augmentation

As an example Martinez outlined thedesign goals of Kopinrsquos ldquoPupilrdquo display module These include size weight batterylife and display resolution The technologyempowers augmented-reality applications thathave already proven valuable in supportingand documenting complex service and main-tenance operations in the field For instancerather than carrying a thick operations manualto a tower antenna or wind turbine needingmaintenance service personnel can call upspecific operational procedures with the addedbenefit of documenting the maintenance thattook place Beyond B2B other applicationsinclude enhanced situational awareness andeven the ability to see through buildings toknow what is on the next street ndash the next-bestthing to X-ray vision

We see the Kopin NTE device as a technol-ogy milestone in the space developed by otherleaders in the field including Google with itsGlass prototype project that pushed the limitsof wearable (OK ldquogeekyrdquo) technology andApple with its ldquotapticrdquo version of a hapticfeedback engine that notifies users with aslight tap on the wrist What will be interest-ing in this space is just how we begin to adaptand take advantage of new sensory input thatmoves us beyond the audio and visual cues wehave previously relied on

At the same conference Margaret KohinSenior VP of eMagin said her company waslooking to use its emissive OLED-XL (on silicon) microdisplay technology with resolu-tions as high as 1920 times 1200 pixels to bridgethe gap between the consumer space and mili-tary applications in HUDs She said eMaginrsquosconsumer applications initiative has been inplace since late 2014 The latest advance inthis area is a 4-Mpixel OLED microdisplaythat offers a luminance of 6500 cdm2 and a90deg FOV (field of view) while deliveringgreater than 75 color gamut with 85 uni-formity Sizes range from 086 in (WUXGA)to 061 in (SVGA) There is even a 15-micromVGA version that weighs less than 2 grams

Kohin also made the point that the mid-term wish list for AR and VR markets is avery good fit for OLED microdisplays Shesaid the wish list includes benchmarks such ashigh luminance in the 20000ndash30000 cdm2

range and high contrast (true black) lowpower consumption (OLEDs require no back-light) and small form factor

If the Google Glass pull-back has discour-aged some companies in the consumer NTEindustry eMagin is not among them At Display Week Kohin was clearly bullish onthe space and said she believes that along withcontinued B2B and government clients theconsumer space is ready to move

Meanwhile in the exhibit hall at this yearrsquosDisplay Week Greg Truman CEO ofForthDD (now part of Kopin) talked to usabout the companyrsquos high-resolution LCoSmicrodisplay business (Fig 2) and the appli-cations opening up in the non-display spaceOne example of the latter is in spatial lightmodulation with applications for its liquid-crystalndashonndashsilicon (LCoS) chips in QXGAresolutions used for automated optical inspec-tion equipment ldquoThe big win comes inimproved accuracy on the production linerdquoTruman told us ldquoin what is now a cubicmicron accuracy businessrdquo While the NTEbusiness is still contributing up to 50 ofKopinrsquos revenue the new field of automatedoptical inspection is helping diversify thebusiness lowering dependence on the displaymarket alone This technology is nowempowering machine vision with a highly dis-crete ability to ldquoseerdquo flaws in solder or otherassembly operations This goes well beyondthe visual acuity of human inspection

Parent company Kopin has a long history ofmaking HUDs for pilots and the firm supplies display components including the

complete optics package driver software asoftware development kit and test and devel-opment platforms for its military and B2Bcustomers which include Thales Elbit andRockwell Collins

Elsewhere in the exhibit hall anothermicrodisplay designer Fraunhofer Institutefor Organic Electronics showed off its newfull-color SVGA bi-directional microdisplayOLED (Fig 3) that serves double duty as botha display and eye-tracking scanner Anembedded image sensor is used to track eyemovements with algorithms designed to targetthe center of the pupil This greatly enhancesthe systemrsquos ability to discern user intentoffering some huge benefits in head-wornmobile personal electronic devices Thedesign includes a four-color (RGBW) pixelarrangement that adds an embedded photo-diode image sensor used to detect light Thedisplay is based on a 018-microm CMOS processchip that delivers an SVGA resolution displaywith a luminance of 250 cdm2 This idea ofembedding sensors into the microdisplay toenhance the overall user experience is encour-aging and will likely continue Early applications include video or data gogglesaugmented-reality eye wear and evenmachine-to-machine applications Once the resolution is enhanced beyond 720pFraunhofer anticipates suitability for bio-metric and security applications that can benefit from discrete iris detection algorithmsbut there is more fundamental chip develop-ment work to be done before those become areality

Fig 2 These ForthDD high-resolution microdisplays shown at Display Week are now used inmachine-vision projects well as high-end viewfinders

Participating in Display Weekrsquos InnovationZone this year was Korea-based Raontechdemonstrating a new 720p HD LCoSmicrodisplay module (05 in 1280 times 720 pixels) in a super-compact 8 mm times 8 mm optical package using an LED light source(Fig 4) This was shown with applicationsproposed for automotive HUDs wearablesmart glasses and pico-projectors moving toHD Dual-display (two-eye) support for display goggles was also on the Raontechproduct offering list We were told a full-HDversion is on the design roadmap

In a technical session devoted to micro-displays Dr Brian Tull from Lumiode aColumbia University start-up company presented a paper titled ldquoHigh BrightnessEmissive Microdisplay by Integration of III-VLEDs with Thin Film Silicon TransistorsrdquoHe also showed the companyrsquos next-generationmicrodisplay a photolithographically pixe-lated LED (think LED-based digital signsshrunk down to microdisplay size) TheLumiode team uses a type III-V semiconductorcompound material that creates an emissivemicrodisplay using TFTs that act as both the

light source and the image component Creating a high-brightness emissive LEDmicrodisplay using TFTs that is based onproven methods used in both LCD glass substrates and OLED display manufacturingrepresents a significant technological achieve-ment According to the company ldquoOur tran-sistor process flow follows a conventionalthin-film process with several modificationsto ensure process compatibility with LED epi-taxial wafersrdquo The result is a monolithicallyintegrated thin-film device using standardGaN-based LEDs from a combined processflow

Tull claims several advantages for his modified conventional thin-film process overtraditional liquid-crystal or micromirrordevices and even over ldquolow lightrdquo emittingOLED-based microdisplays He believes thatLEDs are the best choice for miniaturizationof wearable applications as they offer signifi-cant advantages in the most important displaymetrics a luminance of 20 times 106 cdm2 thehighest efficacy (100 lmW) and the mostrobust lifetimes (50 khours and up) Thisnew approach using type-III and type-V

compound silicon has the potential to shift thedirection of small-display technology perhapsfor generations to come

3D Moves to Eye Tracking at SIDUsing eye tracking along with software coredisplay hardware and a complex set of opticsa company called SuperD that is based inShenzhen China has developed a second-screen mobile-display monitor it calls 3DBox The ldquoBoxrdquo shows 2D content fromsmartphones or tablets in autostereoscopic 3D via a wireless connection with the help of its eye-tracking software

Content in 2D and user (via touch) controlare provided through a wirelessly connectedmobile device for say mobile game interac-tion that can be made viewable on the SuperDdisplay in autostereoscopic 3D Previous versions of this technology surfaced as farback as 2011 using a laptop screen for inputbut recent eye-tracking improvements havemade the 3D effect much more compellingThis is because when the eye position isknown the image can be rendered in 3D inreal time by sending the 3D pixel data througha lens located on the devicersquos LCD panelThis autostereo content is then reflected to the userrsquos eyes

SuperD also sponsored three papers at theDisplay Week symposium including work ona polarizer-free LCD lens and highlights of astudy on the relationship between drivingvoltage and cell gap in a two-voltage drivingstructure In the poster session SuperD alsoshowed contrast enhancement using an elec-trically tunable LC lens performing a focusingfunction by electrically varying the focallength to achieve contrast The advantage isno change to image magnification due tofocusing so contrast is enhanced merely bycontrolling focusing and defocusing of imagesthrough simple arithmetic operations

Another 3D technology found in the I-Zone came from Polarscreens Inc from Quebec Canada This company also makes use of advanced eye tracking by providingfull-resolution stereo vision without 3Dglasses goggles or other worn apparatus byusing a camera-based eye-tracking system It tracks both the head and eyes to create what it calls ldquoeye gaze datardquo using motionprediction algorithms Eye rotation speed and the point of eye focus are calculated from this gaze data and then used to create the 3D effect

Fig 3 Fraunhoferrsquos bi-directional OLED microdisplay appears in the bottom left side of thisimage

Here a stereoscopic video is constructedusing three fields (one common and two alter-nated parallax barriers) They are displayed insequence but at different times consequentlyeach field does not register on the eyersquos retina at the same location due to eye rotation betweeneach field Eye tracking and head tracking areused to determine eye rotation speed in boththe x and y directions and that data is used toshift the video content of each parallax-barrierfield to match the rotation speed reconstruct-ing a perfect image on the userrsquos retina

In essence a computer-generated image isrendered based on the userrsquos viewpoint usingtwo virtual cameras and the motion-predictioninformation re-aligning each parallax fieldrsquosvideo content with the common field at theuserrsquos retina It works for both still imagesand 3D objects and video

One other benefit from this approach sincethe object of focus is known by the system isthat the data can also be used to improve thesharpness of the fixed object while blurringthe background data creating a depth-of-fieldillusion that is quite compelling The FOVranges from just 6 in to a whopping 7 ft thegroup said Eye tracking is disengaged if thehead tilts out of range or 2D content isselected for display This technology wasoriginally developed to counteract the effectof eye rotation during virtual-reality sessionsin glasses-free autostereoscopic systems

A Light-Field-Display Approach to 3DZebra Imaging was in the I-Zone with a holo-graphic light-field 3D display with a self-contained real-time spatial 3D generatordevice incorporating a table-top display that itcalls the ZScape On display were applica-tions in simulation awareness and ldquovisitationrdquoso the group was clearly targeting the militarybut was also able to create dynamic and inter-active images from diverse data sourcesincluding LIDAR CAD biometric andbathymetric (ocean topography) ndash all in realtime This is a full-color auto-viewable (nospecial eye wear) table-top display offeringcompatibility with most common softwareplatforms as well as interactivity with off-the-shelf peripherals (gesture 3D tracked wandsand gloves multi-touch and gaming devicesincluding pointers)

The images are made from an array ofldquohogelsrdquo or holographic elements created inthe light-field display According to ZebraImagingrsquos I-Zone application ldquoThe display

plane is modeled as a 2D array of microlensesthat correspond to camera positions on thedisplay surface defining a mathematicalmodel of the physical emission surface of thedisplay in model space Hogels are computedat the center of every microlens from the perspective of the holographic-display plane3D operations such as pan scale zoom tiltand rotate are accomplished by transformingthe modeled display plane through the scenersquosmodel space Thus the modeled displayplane becomes a window into the 3D scenewhich translates into the projected 3D light-field visualizationrdquo My personal impressionis the technology is yet one more milestone inmoving toward holographic displays withsome useful (even critical) military or securityapplications For example it can providevital real-time data to planners decision makers and perhaps even for medical appsThat said we are still a bit far away from consumer-level displays of this type

University of Seoul 3D Table-TopAnother table-top 3D display in the I-Zonewas from the University of Seoulrsquos HumanMedia Research Center in KwangwoonKorea This immersive table-top 3D displaysystem is called ldquoHoloDigilogrdquo It is a modi-fied conventional direct-view system thatcleverly uses sub-viewing zones and a lensletarray and light-field technology and a QXGAdisplay (3840 times 2160 pixel resolution) flatpanel as the base (floor of the hologram if youwill) It allows for multiple viewing of a 3Dimage that can be projected on to the 238-in-diagonal table-top panel It looks surprisinglygood for a table-top 3D display The groupsaid it had (but did not bring) a 20- and 30-inversion of the display in Korea as well

HoloDigilog consists of a four-part systemthat includes (1) a real-time pick-up of a 3Dscene by capturing its intensity and depthimages (2) depth compensation used to co-ordinate between the pick-up and table-top

Fig 4 This Raontech working prototype board shows wearable LCoS MD modules

display (3) an elemental image array (ELA)that is created through image processing using compensated intensity and depth mapping and (4) the EIA displayed on the immersive table-top 3D display system Total ldquoboxelsrdquo in theexisting system are limited to 300 times 200 times 256vertical and to increase the object projectedan even higher-resolution panel is requiredThere is also an optical projection layer(patent pending so few details were given)

On the application side the group mentioneda table-top display for sporting events etcbut creating content for this display then massdistribution may still be a long way off Evena simple application like the one shown inStar Wars a ldquoPrincess Leiardquo version of FaceTime with 360deg viewing for the entirefamily to see would be an awesome ldquokillerapprdquo But donrsquot mind me ndash Irsquom just dreaminghere The Korea-based group said it is possi-ble to do real-time streaming content but thatit was highly processing intensive In shortthis technology is still in its very early daysbut that said it is exciting to see the progress

HUD Wavelength-Selective ExcitationSun Innovations was at Display Week in the exhibit hall with a full-windshield HUD systemthat renders objects in color using a novelemissive projection display (EPD) Remark-ably images in multiple wavebands between360 and 460 nm will be projected onto a wind-shield coated with Sunrsquos fully transparentemissive films using a UV light projectorThe process is called projective excitation anduses a laser or LED-based HUD projector forwhat company namesake and founder Ted Suncalls wavelength-selective excitation (WSE)

On the materials side specially treatedcolor-sensitive films are made in opticallyclear sheets lt50 microm and stacked in an RGBconfiguration (Fig 5)

This luminescent material is added to standard automotive glass with polyvinylbutyral (PVB) based resin films embedded(used to create shatterproof windscreen glass in cars) Sun stacks these color-sensitive RGBfilms and excites them using a display engine powered with a UV light source each film with

distinctive absorption and emission character-istics to excite the red green or blue layerSun insists there is no extra coating step oradded change to the primary manufacturingprocess used to create the film Best yet Sunsaid these films can be produced in a roll-to-roll process that is low cost and haze-free (nopixel structures to interfere with light trans-missivity) If this sounds like the Holy Grailfor the automotive display industry we agree

For automotive applications Sun combinesthis material with a HUD projector based onblue-ray laser and x-y laser image scanners The group is working on a separately designed palm-sized full-windscreen HUD projector withintegrated control and interface boards to speed adoption and design flexibility In principle theprojector encodes the original color image into three excitation wavebands which excites the corresponding film layer generating the RGB The trick is to do this without interfering with the excitation or emission from other two layers In full implementation this system can dis-play information on any window in the carOther horizon milestones include embeddedsensor integration touch and gesture controland voice commands for hands free operation

Display Evolution Empowers a NewWave of DevicesSo there you have it a primer on micro-displays NTEs and 3D displays at this summerrsquos Display Week And while we seethese examples of new film-based displaysand table-top holograms are still a bit far outit is exciting to see what may be the begin-nings of our future car window living roomand mobile experiences as seen on the Display Week show floor Some milestoneNTE technologies have finally reached sizeweight and battery-life thresholds that willempower the next wave of wearable AR andVR devices These will push us toward anever-tighter integration of virtual and augmented reality with real life In additiondisplays are becoming ubiquitous as sensorsand microprocessors did before them Displays that provide easy access to informa-tion are becoming the norm in virtually allparts of our lives Look for displays to meltinto the background only to emerge whenneeded and perhaps when anticipated by thesmart objects all around us Until that timethe industry continues to work integrate anditerate toward fulfilling our dreams of evermore efficient and seamless devices n

Fig 5 Sun Innovations creates color-sensitive RGB films and excites them with a projector tocreate full-windshield HUDs

Ask us aboutbull E Newsletter Sponsorshipbull Banner Advertising on

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Contact Roland Espinosa Senior Account ManagerPrint amp E-Media Advertising

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ID Ad p29_Layout 1 9132015 153 PM Page 29

AS displays continue to evolve while manufacturers seek to provide users with improved image quality and greater utility there is a tendency for each manufacturer to develop measuring methods that are specific to each display technology even for the same applica-tion These disparate methods can make it dif-ficult to compare performance among different display technologies This is especially true when displays are characterized under ambient illumination where display performance is oftenquoted for inconsistent lighting conditions

For example the ambient contrast ratiomay be specified with a display at 200 cdm2

under 500 lx of illumination However thatlighting information is often insufficient forthe user to confirm the performance or deter-mine if it is applicable to their environmentThe laboratory measurement may have beenperformed with a single light source but typi-cal indoor and outdoor illumination conditionshave two or more lighting sources And each

of these light sources could have differentillumination levels spectra and directionalityAll this can affect how light is scattered to theviewer Therefore simply citing display performance at a specific illumination leveland viewing condition is usually not sufficientto describe the range of use cases A moresystematic approach is needed to manage thecomplexity posed by the range of ambientillumination conditions that may be used

The General Lighting EnvironmentAlthough a display may be viewed under a

large number of lighting scenarios the displayrsquosambient performance is typically evaluated bya common set of observed photometric andcolorimetric characteristics which are largelyindependent of the display technology Fromthe optical-metrology perspective the netphotometric and colorimetric quantities measured at the observation point are usuallyindifferent to the source or multiplicity of thelight In addition since the detectorsemployed to measure the light are fundamen-tally linear radiometric instruments we canemploy linear superposition to determine the

A General Framework for Measuring theOptical Performance of Displays underAmbient IlluminationThe growing diversity of the display landscape requires a unified approach to characterizevisual performance under realistic lighting conditions

by John Penczek Edward F Kelley and Paul A Boynton

John Penczek is a Senior Research Associateat the University of Colorado Boulder Coand at the National Institute of Standards andTechnology Boulder CO He can be reachedat jpenczeknistgov Edward Kelley is aconsulting physicist at KELTEK LLC Paul Boynton is an Electrical Engineer at the National Institute of Standards and Technology Gaithersburg MD

frontline technology

Fig 1 This general viewing scenario of a display shows front- and back-illumination fromhemispherical diffuse and directional light sources

ID Penczek p30-35_Layout 1 9132015 155 PM Page 30

magnitude of the optical signal from multiplelight sources by summing up the individualcontributions However it should be notedthat the presumption of linear superposition inthe detection of the optical signal does notmean that the human visual system is linearVision science has demonstrated that our perceived sense of brightness and color is sensitive to adaptation mechanisms1

There are extensive vision models to simu-late these mechanisms if more accurate perceptual results are necessary Howeverthese visual models still rely on the photo-metric and colorimetric data as inputs whichare taken by linear optical detectors We canleverage the concept of linear superpositionfor luminance and spectral radiance (or absolute

tristimulus values) to simulate complex lightingenvironments from individual source measurements

Figure 1 illustrates the situation of a generaldisplay under arbitrary illumination In thecase of an emissive or transmissive display(eg OLED or LCD) in a dark room theviewer only observes the emitted luminance(Lem) or color If the display is observed in anilluminated room or in daylight the illumina-tion from hemispherical diffuse (EFhemi) anddirectional (EFdir) light in front of the displaywould produce a net reflected luminance (Lr)that would add to the emitted light And inthe case of a transparent display the illumina-tion from hemispherical diffuse (EBhemi) anddirectional (EBdir) light in back of the display

would produce an additional transmitted luminance (Lt) to the viewer

In general the total luminance perceived bythe viewer would be the sum of the three contributions (Lem + Lr + Lt) If a spectro-radiometer was used to measure the spectralsignal at the viewerrsquos position the total spec-tral radiance would add up on a wavelengthbasis The spectral information could then beused to calculate both the luminance and colorof the signal This model can also be appliedto a reflective display which would only havea reflected contribution (Lr) if it was opaque

The use of linear superposition in thismodel may appear simplistic but as we willshow shortly the extension of this conceptinto the display metrology can yield valuable

Fig 2 The above represents the general formalism for simulating the ambient performance of displays

benefits Our analysis will also assume that the focus of the viewer is on the display screen In some situations such as specular images or viewing objects behind transparent displays the viewerrsquos focus may be at a different posi-tion In those situations the content on the screen will interfere with the off-screen image We will however limit our discussion to thedisplayrsquos on-screen performance

When evaluating the performance of a display under ambient lighting conditionsthere are numerous possible lighting configu-rations However for daylight conditionsthere are two main light sources The hemi-spherical skylight provides omni-directionalillumination and sunlight illuminates the display with rather directed rays The illumi-nance levels from both of these componentsare a function of the display orientation itsposition on the earth the season time of dayetc The Illumination Engineering Society ofNorth America (IESNA) has developed anempirical model to estimate the illuminancelevels for both the hemispherical diffuse illu-mination of the skylight and directional illu-mination of the sunlight2 However theIESNA model does not provide color informa-tion which is necessary to predict the resultingcolor Alternatively the National RenewableEnergy Laboratory (NREL) in the US hascollected a substantial amount of spectral irradiance data for solar energy research anddeveloped a spectral model for skylight and

sunlight3 Both of these daylight models werefound to yield similar illuminance levels forthe test cases we explored But the spectraldata available from the NREL model providesthe complete information needed to calculateboth luminance and color results

Indoor illumination can be more varied thanoutdoor There may be several luminaires (ordirectional sources) in a room but we canconsider there to be only one hemispherical diffuse source The hemispherical illumination may originate from luminaire light that dif-fusely scatters off indoor surfaces or the lightfrom windows For the example shown inFig 1 we limited the indoor lighting scenario on the right side of the display to one luminaire The relative amount of hemispherical diffuse to directional illumination on the screen dependsgreatly on the lighting conditions Howeverfor offices with windows the hemisphericaldiffuse illumination originating from windowlight can be a dominant contributor

A General Display Formalism As suggested in Fig 1 the luminance (orspectral radiance) that is measured at theobservation point will be the sum of all thecontributing light sources This can be

expressed mathematically by the expression inFig 2 where the contribution of each externallight source can be represented by their frontreflection (RFhemi and RFdir) and back trans-mission (TBhemi and TBdir) coefficients andtheir relative illumination levels The geo-metric dependencies of the reflection andtransmission coefficients on the light sourceand detector configuration have been omittedfor simplicity When the measurements aremade in terms of photometric units (ie lumi-nance) we refer to luminous reflection andtransmission coefficients The general equa-tion can also be expressed in its spectral formwith equivalent spectral reflectance and trans-mittance factor distributions The originalconcept was put forth by Kelley et al to takeinto account ambient reflections but has beenrecently generalized to include transparentdisplays45

The reflection and transmission coefficientsare fundamental display characteristics thatdescribe how light is scattered when measuredat a given illumination and detection geometryDisplays will usually exhibit a linear responseto the incident light which means that thereflection and transmission coefficients willremain constant for typical levels of illumina-

Fig 3 The above close-up image of a trans-parent LCD pixel structure shows a renderingof a magenta color (green pixels off) Thisdesign uses a clear section in the middle ofeach subpixel

Fig 4 Spectral transmittance factor distributions for the transparent LCD are measured withback-illumination from a hemispherical diffuse light source The legend at the bottom indicatesthe color the display was rendering during the measurement

tion This invariance enables the reflectionand transmission coefficients to be measuredat modest illumination levels and the generalequation then allows the display luminance tobe calculated at low or high illumination levels The illumination scaling propertyyields even greater benefits when performingspectral measurements In that case the spec-tral reflection and transmission distributionscan be measured with a convenient lightsource (eg tungsten lamp) but the reflectedor transmitted spectra can be calculated for anideal source such as CIE Illuminant D65Using the spectral form of the general equa-tion also allows us to calculate the effectivecolor observed from the combined sourcesThe detailed methods for measuring thereflection and transmission coefficients aregiven elsewhere67 However we highlightthe utility of this method by applying it to several lighting scenarios

Applying the Formalism We demonstrate the value of the proposed formalism by simulating the ambient per-formance of a commercial transparent 22-in-diagonal TN-LCD panel under various appli-cation scenarios A photograph of the pixelstructure used by this LCD is shown in Fig 3with hemispherical diffuse white back-illumi-nation Since this is not an emissive devicethe RGB color-filter array must be externallyilluminated in order to be visible The spec-tral distribution of that illumination will alsoimpact the resulting color gamut of the deviceTherefore this structure is strongly affectedby the illumination conditions

The response of the transparent LCD toambient illumination was characterized byusing a white hemispherical diffuse lightsource (with specular included di 0 detectorat normal incidence) and a directional sourceat 45deg inclination to the display Since theperiodicity of the active-matrix structure tendsto induce diffractive scatter with discretedirectional sources a ring light source wasused instead These illumination sources wereemployed in front and back of the display tomeasure the reflection and transmission characteristics In our tests a spectro-radiometer was used in order to measure thespectral reflectance and transmittance factordistributions This allowed us to accuratelymodel the color response of the display to avariety of other (ideal) light sources If photo-metric characteristics (eg contrast ratio)

were of primary concern then photometerscould be used

The measured front spectral reflectance factor distributions for both hemisphericaldiffuse and directional illumination weremeasured to be fairly consistent for the rendered red green blue cyan magenta yellow white and black (RGBCMYWK) colors However the spectral transmittancedistributions measured by back-illuminationstrongly depended on the rendered color Figure 4 shows the measured spectral trans-mittance factor distributions for the transpar-ent LCD with back-illumination from a

hemispherical diffuse light source The redgreen and blue distributions resemble thetransmission curves for typical RGB filtersHowever in this device design (see Fig 3)each color subpixel has a clear middle sectionthat transmits broadband light Thereforewhen the display is rendering a red color (forexample) the measured spectral transmittancein Fig 4 indicates that green and blue wave-lengths are also transmitted The spectralreflectance and transmittance factor distribu-tions can be weighted by the photopicresponse of the eye and expressed as scalarvalues The front luminous reflectance and

Table 1 Reflection and transmission coefficients are used to evaluate thetransparent LCD performance Corrected to a CIE Illuminant D65 white lightsource

Table 2 Ambient illumination conditions are shown for several lighting environments where transparent displays may be used

back transmittance factor coefficients for thetransparent LCD are summarized in Table 1

The performance of the transparent displaywas evaluated for the three ambient illumina-tion environments listed in Table 2 The

indoor and outdoor conditions replicate theambient lighting conditions used by severalstandards689 The showcase lighting condi-tions are typical of how transparent LCDs arecurrently used in point-of-sale situations

Note that the illumination level geometry andlight-source spectra are specified in order toaccurately represent the lighting environment

The ambient lighting conditions wereapplied in four viewing scenarios These scenarios are tabulated in Table 3 using thebackfront notation to identify which illumina-tion conditions are used in back and in frontof the display relative to the viewer Theindoorindoor scenario simulates the lightingenvironment when the display is used in anoffice setting The showcaseindoor scenarioestimates the lighting conditions when the display is the front face of a lighted boothinside of a building The outdoorindoor configuration approximates the case when thedisplay is mounted in a window with theindoor viewer looking outside And the showcaseoutdoor setup simulates the situa-tion where the display is a window to a store-front and the viewer is outside

Each of the viewing scenarios listed inTable 2 was evaluated following the expres-sion in the equation box using the coefficientsin Table 1 and the lighting levels in Table 2The ambient contrast ratio can be obtainedusing the photometric form of the expressionin the equation box In this case the colordependence of the transparent LCD transmis-sion coefficients did not produce a significantimpact on the ambient contrast ratio calcula-tion for the illumination levels used in ourscenarios However the actual spectral trans-mittance factor distributions were needed todetermine the effective colors and conse-quently the color gamut area The colorgamut area listed in Table 2 was calculated asthe percent area covered by the effectiveambient RGB colors on a CIE 1976 chro-maticity diagram relative to the sRGB gamutarea (see Fig 5)

The previous example illustrated how thedisplay ambient performance can be predictedby using the general model for the complexcase of a transparent display The simpler situation of a conventional opaque display can also be evaluated We demonstrate this by only measuring the hemispherical diffuse and direc-tional reflection coefficients of a commercialtablet display and evaluate the display indoorand outdoor performance using the illumina-tion conditions given in Table 2 The contrastratio and color gamut area for the tablet display at 200 cdm2 is summarized in Table 4 The color gamut of the tablet display is alsocompared to the transparent LCD in Fig 5

Table 3 Ambient optical performance of the test transparent LCD is measured in various viewing scenarios

Fig 5 The CIE 1976 chromaticity diagram illustrates the color gamut of the transparent LCDand tablet display under the various scenarios listed in Table 2

Table 4 illustrates the sharp reduction in thecontrast ratio of the tablet display as the illu-mination is increased to full daylight levels It is interesting to compare this with the trans-parent LCD In both cases the contrast ratiois constrained by the reflected ambient lightwhich raises the black level But the transparentLCD can utilize the high back-illuminationlevels to achieve on-screen contrast ratios thatcan sometimes exceed the tablet display undersimilar conditions However Fig 5 illustratesthat even the high back-illumination levelscannot substantially improve the relativelynarrow color gamut of the transparent LCDThe clear mid-section of this subpixel designwashes out the transmitted colors by allowingbroadband light through the color-filter arrayand severely limits the displayrsquos color gamutOther transparent LCD designs have sincebeen introduced and are expected to have significantly better performance TransparentOLED displays are also expected to enter themarket The proposed methodology is capable of fairly evaluating either of thesetechnologies

This example illustrates how the new generalized framework for display ambientperformance can be used to simulate manylighting scenarios from a basic set of reflec-tion and transmission measurements Byframing the analysis in terms of the intrinsicreflection and transmission characteristics ofthe display we can estimate the display performance without physically assemblingand measuring the actual lighting environ-ment Since some lighting scenarios can becomplex with special spectra and high illumi-nation levels they are difficult to replicate andtend to produce unstable measurements The

linear superposition concepts employed in ourmethod breaks that paradigm in favor of simple well-controlled transmission and reflection measurements with single lightsources This approach will yield reliablemeasurements that can be applied morebroadly than legacy methods

References1G Wyszecki and WS Stiles Color Science Concepts and Methods Quantitative Data and Formulae 2nd ed (John Wiley amp Sons 2000)2The IESNA Lighting Handbook Referenceand Application Illumination EngineeringSociety of North America 9th ed (2002)3ASTM G197-08 Standard table for referencesolar spectral distributions Direct and diffuseon 20deg tilted and vertical surfaces (2012)4E F Kelley M Lindfors and J PenczekldquoDisplay Daylight Ambient Contrast Meas-urement Methods and Daylight ReadabilityrdquoJ Soc Info Display 14 1019ndash1030 (2006)5J Penczek E F Kelley and PA BoyntonldquoGeneral metrology framework for determin-ing the ambient optical performance of flatpanel displaysrdquo SID Digest of TechnicalPapers 46 (2015)6International Committee for Display Metrol-ogy (ICDM) Information Display Measure-ments Standard (IDMS) ver 103 section 11(2012) httpwwwicdm-sidorg7J Penczek E F Kelley and P A BoyntonldquoOptical measuring methods for transparentdisplaysrdquo SID Digest of Technical Papers 46(2015)8IEC 62679-3-1 Ed10 Electronic paper dis-plays - Part 3-1 Optical measuring methodsInternational Electrotechnical CommissionApril 24 2014

9IEC 62341-6-2 Ed10 Organic light emittingdiode (OLED) displays - Part 6-2 Measuringmethods of visual quality and ambient per-formance International Electrotechnical Commission Jan 24 2012 n

Table 4 The ambient optical performance of a commercial tablet device witha 200 cdm2 LCD is charted under the indoor and outdoor illumination condi-tions given in Table 2

Display Week 2016SID International Symposium

wwwdisplayweekorg

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JOIN SIDWe invite you to join SID to participate in shapingthe future development of

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Acolorimeter comprises at least threeopto-electrical detectors each in combinationwith a filter to match the overall spectral sensitivity of these combinations to those ofthe CIE 1931 color-matching functions Theelectrical output of each of these color chan-nels is proportional to the tristimulus valuesX Y and Z When the detectors deliver output signals according to the sum of thelight intensity across the field of measure-ment the device is called a ldquospotrdquo-meterWhen two-dimensional arrays of detector elements are used instead ndash again in combina-tion with appropriate filters ndash a correspondingarray of area elements on the object of measurement can be analyzed with respect toluminance Y and chromaticity eg x y

Instruments of the latter type are calledimaging colorimeters because the color chan-nels can analyze the surface area of objectsand scenes and generate data arrays (of lumi-nance and chromaticity levels) just like cameras deliver RGB images The detectorarrays can be provided with color filters onthe individual elements (eg RGB filters) or afilter wheel with at least three filters can be infront of the array for time-sequential coloranalysis usually in terms of the tri-stimulusvalues X Y and Z Imaging colorimeters alsorequire a suitable optical system for

projection of a region of the surface of theobject of measurement through the filters onthe detector array Imaging colorimetry hasgained popularity due to its convenience andpotential for making sophisticated automatedanalyses

Instruments for colorimetric analysis viaspectral measurements (spectral power distri-bution) are currently of the spot-meter type so they have to be carefully aligned in order to make sure that the field of measurement iscorrectly positioned on the object to be measured Incorrect positioning can causesevere measurement errors especially in thecase of objects with complicated displaystructure and layout (eg automotive dash-boards and displays) Such complex displaydevices can be analyzed much more easilywith imaging colorimeters because the actualcolorimetric analysis can be performed afterrecording of the image and identification ofthe regions of interest can be automated Thisease of use is the motivation for developmentand implementation of techniques thatincrease the precision of colorimetric analysisfor arbitrary spectra as described in this article

Objective and BackgroundThe measurement accuracy of imaging colorimeters crucially depends on the qualityof the optical filters in use Enhancing the fitof the filters with the human eyersquos color-matching functions (CMFs) improves theaccuracy of the measurements As a result ofthe unavoidable spectral mismatch of the

colorimeter response functions relative to theCMFs the accuracy of measurement varieswith the spectrum of the device being testedUsually three filters are used one for eachCMF More advanced devices use four filterssince one of the CMFs exhibits two disjunc-tive spectral regions that can be more accu-rately matched with two filters In technicalterms even the best filters available will stillnot perfectly match the corresponding CMFand this will inevitably generate measurementerrors most prominently at both ends of thespectral range of human vision One approachto improving results is the use of additionalfilters to collect more information in thesespectral regions However simply extendingthe number of filters ie the number of data-acquisition channels will not necessarilyimprove measurement accuracy A negativeside effect is the significant increase in themeasurement duration with the number of filters in use

Measurement accuracy will increaseaccording to the spectral match of the deviceunder test and of the calibration source Sincecalibrations are frequently made using whiteincandescent sources LEDs and coloredsources often create large errors in measure-ment Matrix correction methods are used tocorrect display measurements and reduce sucherrors There are generally three primaries ofthe display that are mixed to give the testcolor and hence there is a limited variation inspectra The matrix method of correction isnow commonly applied to such measure-

Advanced Imaging ColorimetryImplementing advanced methods of display metrology enables highly accurate luminance andcolor-imaging measurements to be performed The next generation of high-accuracy imagingcolorimeters benefits from a combined approach of recording additional data and utilizing amatrix-based optimization algorithm

by Đenan Konjhodžić Peter Khrustalev and Richard Young

Đenan Konjhodžić Peter Khrustalev andRichard Young are with Instrument SystemsĐenan Konjhodžić can be reached at konjhodzicinstrumentsystemscom

ID Konjhodzic p36-40_Layout 1 9132015 215 PM Page 36

ments but it cannot be used if the spectrum iscompletely unknown Matrix methods canstill be applied to improve results in specificcases

Here we present a combined approach forextending the number of color filters fromfour to six together with advanced matrix-based optimization methods A matrix opera-tion can derive the three tristimulus valuesfrom the six measurement values This correction matrix can be optimized across alarge set of sources so that no inherentassumption of spectrum is required Onlycombining both methods yields more accurateresults for practically all sources compared tostandard methods of today This article developsthe theoretical proposals given as referencesto include practical implementation and performance tests of actual devices The goalof this work is to produce a better colorimeterthat also works well when you need to measure an arbitrary or unknown spectrasource

Optimizing Spectral ResponsesColor-matching functions which form thebasis for most measurements of color quanti-ties are shown in Fig 1 as solid lines A typical colorimeter aims to reproduce thesespectral response functions using a combina-tion of filters and detectors and although thematch can be close it is never exact Anexample of a four-filter colorimeter is shownas dashed lines in Fig 1 The CIEx color-matching function is realized using two channels on the colorimeter (X1 and X2) forthe two peaks This example shows thatregions of mismatch occur around specificwavelengths Significant errors are expectedfor such sources because LEDs may have narrow-band emissions in these regions

Combining the channels is one way of improv-ing the match However if the response is improved in one region the response in another region is likely to be worse There are manypossible optimizations and each depends onthe spectrum of the source to be measuredThe source spectrum is generally unknown soa compromise combination is required thatminimizes the errors from each source

Adding a 5th or 6th channel greatlyincreases the possibilities for optimization andreduces dependence on the source spectrumFigure 1 provides an example of using sixchannels to conform with the CIE CMFs moreexactly The match here is dramatically

improved in both the 530- and 560-nmregions This can be represented mathemati-cally by a matrix product of six channelresponses with a 3 times 6 adaptive matrix M of

factors for the combinations of channelsresulting in three tristimulus values

The response of these extra channels wouldtypically be single peaks at appropriate wave-

Fig 1 Color-matching functions and examples of implementation appear in the above chartCIE CMFs are solid lines four-channel colorimeter examples are dashed lines and six-filtercolorimeter examples are dotted lines7

Fig 2 Shown are color-difference vector plots in the CIE 1931 xy color space illustrating theerrors in the measurement of various sources using four- (left) and six-channel (right) imagingcolorimeters The vectors point from the true value to the measured value reported by theinstrument The vectors are enlarged by a factor of 3 to improve visibility7

lengths to correct errors in the other fourchannels but this is not a strict requirementNarrow-band responses may introduce localcorrections but be of limited general use Theoptimum responses of these extra channelsshould therefore be matched to the errors inthe basic four channels It is useful to look atcolor errors for general matching Color-difference vector plots such as those shown inFig 2 illustrate the errors with vector arrowsand this conveys an immediate visual impres-sion of distinct characteristics The true co-ordinates (measured using a high-qualityspectroradiometer for real sources or calcu-lated for simulated sources) are shown as circles and the colorimeter-measured coordi-nates are at the tip of an arrow originating inthe circle The length of the arrow indicatesthe magnitude of the error and the direction ofthe arrow gives the direction of change Thearrows are too short to be seen clearly for usein quality systems so they are magnified by ascaling factor to highlight the differences Forexample the vector scale is 3 in Fig 2 anddisplays the arrows three times longer thanthey actually are When comparing errors theshorter the arrow the lower the error

The sources represented in Fig 2 includereal and simulated sources A set of 20-nmFWHM Gaussian distributions represents

pseudo-monochromatic sources such asLEDs In the CIE diagram these are locatedaround the outer edges close to the mono-

chromatic locus A further set of 20 coloredand white LEDs plus four white and filteredincandescent sources are included These aredistributed at the edges and toward the middleof the diagram

There is a clear general improvementresulting in lower errors for all sources whengoing from a four-channel to a six-channelcolorimeter The only limitation is that thosespectral components lying beyond the wave-length range of the filters cannot be correctedin this general way so the errors are the samefor both systems The color-difference vectorplots in Fig 2 are calculated by least-squaresoptimizations to the CMF spectra and as suchthey are perhaps the most general Howeverthis requires knowledge of the spectralresponsivities of each channel

Optimizing Color Errors betweenSourcesIf specific types of spectral sources are antici-pated in the measurement typical sources canbe used (a training set) to minimize errorsacross the set This procedure no longerrequires knowledge of the spectral responsivi-ties of the channels but instead the tristimulusvalues of the training set must be known Theoptimization can be for any specific derivative

Fig 3 Above are spectra of three white and 16 colored LEDs used as a training set coveringthe entire spectral range The spectra are measured with a spectroradiometer and provide precisely determined xy color coordinates as references for matrix optimization

Fig 4 The chart shows color-coordinate deviations of test LEDs for measurement with a six-filter imaging colorimeter

color space or output quantity eg CCT orxy color coordinates

The training set should represent the typicalvariation in measured sources such as thoseshown in Fig 3 An entire spectral rangeneeds to be covered and several white sourcesincluded Figure 4 shows an example of measurements for which a training set of threewhite and 16 colored LEDs was used Aftercompleting the calibration and application ofmatrix optimization for xy color coordinatesthe training set is used for verification Thediagram shows that color-coordinate deviationsΔx and Δy are below 0005 for all LEDsImproved all-round performance is obtainedfor the whole set

The higher accuracy of the optimized six-filter imaging colorimeter for determining thecolor coordinates is also reflected in the calcu-lation of the dominant wavelength as shownin Fig 5

It is important that the training set includesall the required sources to be measured How-ever some sources might be considered moreimportant than others in terms of accuracyand this can be accommodated using weight-ing factors in the optimization

Obviously there can be as many adaptive matrices as there are output parameters so eachcan be individually optimized However ifthis is the case it should be noted that measure-

ment results obtained with different optimiza-tion matrices are no longer related by normaltransforms and cannot be interconverted

Practical implementation requires the chosen matrix to be robust and stable duringnormal use so that multiple matrices are

avoided depending on conditions or the display being measured Figure 6 shows thatthe matrix can be used at different distancesindicated by the measurement points plottedclose to the ldquoequivalencerdquo line Althougheach lens used has its own matrix they allgive equivalent results Similar analyses oftemperature changes and fnumber changesshow they too exert a generally insignificanteffect Results on different systems showclose correlation with those obtained using aquality spectroradiometer

Study of Different Test SourcesAnother study was made consisting of 22samples including LEDs and filtered incan-descent sources that were not included in thetraining set Each source was measured usinga high-quality spectroradiometer as a refer-ence and a colorimeter possessing the basicfour filters (normal) or six filters (advanced)The six-filter system was optimized for mini-mum x and y differences

Figure 7 shows the results of the study ascolor difference vector plots Note that thevector scale is 10 to clearly show the errorsinvolved Although white sources are accu-rately measured with the four-channel systemcolored sources give large errors In contrastthe errors for all sources are small using thesix-filter system

Fig 5 The chart shows a comparison of deviations in the dominant wavelengths for differenttest LEDs for four-filter (red) and six-filter (blue) imaging colorimeters

Fig 6 Shown are equivalence plots for use at different distances for a wide range of white andcolored incandescent sources and LEDs

The Case for ColorimetersThe convenience of imaging colorimeters forperforming complex characterizations of displays has made it the technology of choicein many applications However the accuracyof color and luminance values obtained haslimited their reliability The study has demon-strated that a six-channel imaging colorimeterutilizing a matrix-based optimization algo-rithm gives a significant accuracy improve-ment compared with traditional three- orfour-channel systems The colorimetric accu-racy of this method approaches that of high-quality spectroradiometers while maintainingthe benefits of imaging technologies

Optimization of the adaptive matrix can begeneralized for all sources by a least-squaresfit to CIE color-matching functions Thisoptimizes the effective responsivity of the system and does not require prior knowledgeof the source to be measured However itdoes necessitate knowledge of the channelspectral responsivities

Nevertheless if knowledge of the tristimulusvalues for sources is available the adaptivematrix can be optimized to a specific outputparameter eg CIE color coordinates x and yThe spectral responsivities of channels are nolonger required Optimization using a trainingset and a target algorithm will generallyreduce errors inside the wide range of thetraining sources Optimization can include

weighting if some sources are more importantthan others in terms of accuracy

This study of 22 samples including LEDsand incandescent sources verified the benefitsof using an advanced (six channel) instead ofa normal (four channel) imaging colorimeter

References1J J Jensen ldquoAdvantages and Applicationsfor the Use of Imaging Colorimetersrdquo ProcCORM Conference (2013)2G P Eppeldauer ldquoSpectral Response BasedCalibration Method of Tristimulus Colorime-tersrdquo J Res Natl Inst Stand Technol 103615 (1998)3Y Ohno and J E Hardis ldquoFour-ColorMatrix Method for Correction of TristimulusColorimetersrdquo Proc ISampT Fifth Color Imag-ing Conference 301ndash305 (1997)4J D Schanda and Z T Kosztyaacuten ldquoIndustrialcolorimetry with image resolutionrdquo ProcBulg Color Conference 1ndash5 (2008)5Z T Kosztyaacuten G P Eppeldauer and J DSchanda ldquoMatrix-based color measurementcorrections of tristimulus colorimetersrdquoApplied Optics 49 12 2288ndash2301 (2010)6R Young and J Neumeier ldquoHigh accuracyimaging colorimetryrdquo CIE x0392014 461ndash469 (2014) n

Fig 7 Final study results show a four-channel filter (left) and six-channel optimized systems(right)

Display Week 2016Networking Events

May 22ndash27 2016Looking to meet up with

your colleagues in the displayindustry to discuss

technology business or just socialize The events

below present just that type of opportunity

Annual Awards Dinner MondayEach year SID recognizes individualsthat have played a critical role inimproving the display industryThis yearrsquos winners will be honoredat an awards banquet taking placethe evening of May 23Business Conference Reception Monday Follows the Business Conferenceplease note conference attendance isrequired for admissionAnnual Award LuncheonWednesday The annual Best in Show and DisplayIndustry Awards Luncheon will take place at noon on Wednesday May 25 Both awards are peer-reviewedsuch that the luncheon is well-attended by captains of industry forhigh-level networking and recogni-tion of the best in the industry overthe last yearInvestors Conference The IC will feature presentationsfrom leading public and private companies in the display technologysupply chain and encourage ques-tions and discussion between pre-senters and participants Concludeswith Drinks amp Displays NetworkingReception with Presenters andInvestorsMarket Focus Conference Reception Wednesday May 25 Follows the Wednesday MarketFocus Conference title and programTBD please note conference atten-dance is required for admissionwwwdisplayweekorg

International Display Workshopsto Take Place in Otsu JapanThe 22nd International Display Workshops(IDW) will be held December 9ndash11 2015 inOtsu Japan These workshops sponsored bythe Society for Information Display and theInstitute of Image Information and TelevisionEngineers include oral presentations byinvited and contributing speakers as well asposter presentations discussions and specialRampD updates Exhibits by universities anddisplay-industry-related businesses will alsobe featured in parallel with the workshops This yearrsquos event will feature 15 technical

topics in various fields of importance to theinformation-display industry Four specialtopics of interest mdash Oxide-SemiconductorTFTs Augmented and Virtual Reality Light-ing Technologies and Printed Electronics ndashwill be highlighted this year The three-dayconference will feature 365 papers This year IDW will present an ldquoIDW Best PaperAwardrdquo and an ldquoIDW Outstanding PosterPaper Awardrdquo based on originality and techni-cal significance to information displays Inaddition Nobel Laureate (2014 prize inphysics) Professor Hiroshi Amano of NagoyaUniversity will give a special address onWednesday December 9 IDW 15 should beof interest to not only researchers and engi-neers but also managers of companies andinstitutions in the display communityThe event takes place at the Otsu Prince

Hotel on the south edge of Lake Biwa thelargest lake in Japan (Fig 1) Otsu is about 10 km from Kyoto and is rich in history andnature Numerous historical sites such as theMii-dera and Ishiyama-dera temples arelocated in the cityFor more information visit httpswww

idworjp n

NEWSSOCIETY FORINFORMATION

DISPLAY

Fig 1 The city of Otsu stands on the shore ofscenic Lake Biwa the largest lake in Japan

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Also in the January issue was a review ofthe recently held IDRC (International DisplayResearch Conference) in Monterey CA Hottopics included new research into polycrys-talline-silicon TFTs and the possibility of amaking a projection engine from TFT-LCDsusing this technology Progress in many othertechnologies such as color plasma displaypanels electroluminescent displays single-crystal-silicon TFT arrays CRTs and diamond field emitters for field-emission displays (FEDs) were also reported on Itrsquosclear by this point that CRTs were the maturetechnology and much of the ongoing researcheffort was on the many other growing technol-ogy options

Another milestone from January 1995 wasthe announcement of the ldquoThe Video Process-ing Laboratory at NIST Gaithersburg MDrdquowhere interested researchers could use theconsiderable computer resources available tosimulate various aspects of display visual performance including image quality andhuman visual perception issues Also discussed was the planned development of theNIST Display Measurement Laboratorywhich we now know led to the creation of awhole family of display-metrology standardsand whose work was eventually taken over bythe SID-supported International Committee ofDisplay Metrology (ICDM)

Browsing through the rest of the 1995 issues reveals interesting work in medical imagingwith CRTs news of INFOCOMMrsquos Projec-tion-Display Shootout early developments inLCD-based projection engines innovativedevelopments in touch technology advancesin both field emission and plasma technolo-gies improvements in materials and manufac-turing processes such as ITO sputtering andof course some nice articles about CRTs

One other interesting story we came acrossduring our digitizing work was another articleby Ken Werner this time in the December1995 issue heralding the launch of the SIDDisplay of the Year and Display Product ofthe Year awards In the article is the story ofthe origin of the awards the names of thecommittee members and of course the firstwinners Who were they Display of theYear went to the Texas Instrumentsrsquo DigitalLight Processing (DLP) engine incorporatingthe Digital Micromirror Device (DMD) withan honorable mention to Fujitsursquos 21-in colorplasma display Display Product of the Yearwent to Casio for the first digital camera to

have a 18-in TFT-LCD built into it Can youbelieve this was 20 years ago This is all justa taste of the rich history of display technol-ogy you can find in each of the back issues ofID we are slowly resurrecting

Our current issue this month covers ourreview of Display Week 2015 from San Josein June as well as a couple of great articles ondisplay metrology We lead off with the Display Week coverage grouped into severalkey topical categories covering the gamut ofthings on display and presented at the confer-ence We can do this because of the dedicatedeffort of our contributing authors Ken WernerTom Fiske and Steve Sechrist We have alsodeveloped our own overview for you to seehow all the pieces seem to fit together andexplain more about the significant themes ofthe event including the huge presence ofChina-based display manufacturers this yearWhether you were there with us or not I thinkthe comprehensive reports from each of thesecontributors will help you gain a better appre-ciation for where the industry is going todayA fun project would be to look back at theInformation Display show review issues for2010 2005 2000 1995 and so on to form along-range view of the major themes of thedisplay industry You can do this today backto 2004 on our website where there arealready a few issues dating back to the mid-90s and even earlier

One of the highlights for me at Display Week each year is the chance to participate in theselection of the Best-in-Show award winnerschosen from all the great exhibitors in threesize categories This year the field was greatand the choices really hard but I think thecommittee did an excellent job capturing the most innovative and informative exhibits Ourown Jenny Donelan has compiled these results for you along with the story of the winner of the I-Zone award as well I wonrsquot steal the headline or the unveiling of the winner from her so youneed to go to her article to get it all first-hand

Our technology theme for this month is display metrology and Guest Editor Tom Fiske drew double-duty between his efforts to develop the next two great Frontline Technology storiesas well as provide his coverage of DisplayWeek 2015 The field of optical metrology is still very alive vibrant and staunchly sup-ported by some great people with whom I wasprivileged to hang around in San Jose at theICDM (International Committee for DisplayMetrology) meeting The people on this com-

mittee are truly passionate about their workand are looking at very important topics inmetrology especially as related to emergingdisplay capabilities such as transparencyTransparency is certainly the right word bothin terms of the measurement results them-selves as well as the new considerationsbrought about by the developments in trans-parent displays As Tom explains in his guesteditorrsquos note authors John Penczek EdwardF Kelley and Paul A Boynton describe acommon-sense approach to the characteriza-tion of the reflective and transmissive proper-ties of displays in their Frontline Technologyarticle titled ldquoA General Framework for Meas-uring the Optical Performance of Displaysunder Ambient Illuminationrdquo

In order to make good measurements youneed good instrumentation and there is certainly no shortage of that in the market-place today But just like in any field therange of options includes trade-offs in termsof cost performance accuracy etc Color-imeters are a class of instrument that give yougood results for a reasonable investment butgenerally rely on three or four tri-stimuluscolor filters for computation of chromaticityImaging colorimeters are an especially usefulinstrument because they combine the ability tocapture and analyze spatial information aswell as color and luminance information all atthe same time However for some measure-ment applications their color accuracy maynot be enough because of the well-known limitations of tri-stimulus color filters Asauthors Đenan Konjhodžić Peter Khrustalevand Richard Young from Instrument Systemsexplain by developing a six-channel (six-filter) imaging colorimeter as well as utilizinga matrix-based optimization algorithm theycan demonstrate significant accuracyimprovements making colorimeters even moreattractive options for display-metrology appli-cations I learned a lot about their work andthe general challenges of this technology fromtheir Frontline Technology article ldquoAdvancedImaging Colorimetryrdquo and I am very pleasedthey were willing to share it with us

Having started down the path of exploringIDrsquos history I think even more about whatpeople 20 or more years from now mightthink about what we write today and Irsquom gladthis issue offers so much in terms of industryinsight and technical depth I hope you feelthis way as well and we welcome your com-ments and feedback as always n

continued from page 2

editorial

Abrisa TechnologiesAdvantechApple IncApplied Concepts IncApplied Materials IncAU Optronics CorpCentral China Display LabCima NanoTechCoretronic CorpdpiXDawar TechnologiesDontechE Ink HoldingsEarth LCDElo Touch SystemsEpoxy TechnologyeMagin CorpEntegris IncEuropTec Holding AGEuroptec USA IncFUJIFILM Dimatix IncGoogleHenkelIEEIndustrial Technology Research Institute

I-PEX

Japan Display IncJapan Patent OfficeKuraray Co LtdLEIA IncLintecLMS GlobalLuminitLXD Research amp DisplayLLC

MediaTek USA IncMerck Display Technologies Ltd

MeritecMitsubishi Chemical Corp

Nano-Proprietary IncNANOSYSNLT TechnologiesNoritake Itron CorpNovaled AGNvidiaOculus Optical Filters USAPanasonic CorpParker ChomericsPower OLEDsRicoh

Rolic TechnologiesSakai Display ProductsSamsungSartomer AmericasSharp CorpSolar-Tectic LLC TandemLaunchTannas ElectronicsTCLTDMDATeijin Dupont FilmsJapan Ltd

TFD Inc TLC International TOUCH TURNSTPK Touch SolutionsInc

Universal Display Corporation

US Micro ProductsVestel ElectronicsVisionoxWestar Display Technologies Inc

Wintek CorpYazaki Europe Ltd

Electronic Assembly 5Information Display29Instrument Systems42Konica Minolta 5Masterbond41

Radiant Vision Systems C2 23Rockwell Collins C4SID Vehicle Displays 201511TFDC3

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China Sales Office

Ying WangCorporate Sales Manager ndash ChinaJohn Wiley amp Sons (Asia) Pte Ltd1402-1404 Cross Tower318 Fuzhou Road Huangpu DistrictShanghai 200001 Peoplersquos Republic ofChina

+86 21 5116 3205yingwileycom

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p6-7lo
p8-10lo
p11lo
p12-15lo
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Page 2: DISPLAY WEEK 2015 REVIEW AND METROLOGY ISSUEinformationdisplay.org/Portals/InformationDisplay/IssuePDF/05_15.pdf · DISPLAY WEEK 2015 REVIEW AND METROLOGY ISSUE ... conductors, and