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High Power White LED Technology for Solid State Lighting...

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1 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC Company Confidential Lighting LLC Company Confidential High Power White LED Technology High Power White LED Technology High Power White LED Technology High Power White LED Technology for Solid State Lighting for Solid State Lighting for Solid State Lighting for Solid State Lighting Paul S. Martin Paul S. Martin J. J. Bhat Bhat , C. , C.- H. Chen, D. Collins, W. Goetz, R. H. Chen, D. Collins, W. Goetz, R. Khare Khare, A. Kim, M. , A. Kim, M. Krames Krames, C. , C. Lowery, M. Lowery, M. Ludowise Ludowise , G. Mueller, R. Mueller , G. Mueller, R. Mueller- Mach, S. Mach, S. Rudaz Rudaz, D. Steigerwald, , D. Steigerwald, S. Stockman, S. S. Stockman, S. Subramanya Subramanya , S , S-C Tan, J. Thompson, T. C Tan, J. Thompson, T. Trottier Trottier
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Page 1: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

11 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC Company ConfidentialLighting LLC Company Confidential

High Power White LED TechnologyHigh Power White LED TechnologyHigh Power White LED TechnologyHigh Power White LED Technologyfor Solid State Lightingfor Solid State Lightingfor Solid State Lightingfor Solid State Lighting

Paul S. MartinPaul S. MartinJ. J. BhatBhat, C., C.--H. Chen, D. Collins, W. Goetz, R. H. Chen, D. Collins, W. Goetz, R. KhareKhare, A. Kim, M. , A. Kim, M. KramesKrames, C. , C.

Lowery, M. Lowery, M. LudowiseLudowise, G. Mueller, R. Mueller, G. Mueller, R. Mueller--Mach, S. Mach, S. RudazRudaz, D. Steigerwald, , D. Steigerwald, S. Stockman, S. S. Stockman, S. SubramanyaSubramanya, S, S--C Tan, J. Thompson, T. C Tan, J. Thompson, T. TrottierTrottier

Page 2: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

22 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Who is LumiledsWho is Lumileds

•• Fully integrated light source supplier that coFully integrated light source supplier that co--develops optimized system solutions!develops optimized system solutions!

High Power White LEDsHigh Power White LEDs

•• LED diceLED dice

•• LuxeonLuxeon Power Light SourcesPower Light Sources

•• Arrays of High Flux LEDs on Arrays of High Flux LEDs on a metal core PCBa metal core PCB

•• Automotive, Traffic Signals, Signage & Contour SolutionsAutomotive, Traffic Signals, Signage & Contour Solutions

Page 3: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

33 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

OutlineOutline

•• Competition in the market for Illumination, Incandescent & FluorCompetition in the market for Illumination, Incandescent & Fluorescent Bulbs.escent Bulbs.

•• LED MetricsLED Metrics

•• Options for making white light from LEDsOptions for making white light from LEDs

•• Lumileds power white LED performanceLumileds power white LED performance

•• Some interesting demosSome interesting demos

High Power White LEDsHigh Power White LEDs

Page 4: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

44 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

How Much Energy is Used for LightingHow Much Energy is Used for Lighting

•• In 1999 the US used 3 Trillion In 1999 the US used 3 Trillion kWhr kWhr of Electricity!of Electricity!

•• 20% or 600 Billion 20% or 600 Billion kWhr kWhr of of Electicity Electicity generated was used in Lighting!generated was used in Lighting!

•• Incandescent/Hal. lamps burn 40% of electricity to produce 15% oIncandescent/Hal. lamps burn 40% of electricity to produce 15% of light!f light!

•• Fluorescent/HID lamps use 60% to produce 85% of light!Fluorescent/HID lamps use 60% to produce 85% of light!

•• Illumination market is $60Billion/yr and growing slowly, ~2%/yrIllumination market is $60Billion/yr and growing slowly, ~2%/yr

Illumination MarketsIllumination Markets

Page 5: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

55 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Incandescent BulbsIncandescent Bulbs•• Incandescent = hot light, emitted from a (tungsten) filament at Incandescent = hot light, emitted from a (tungsten) filament at around 2800around 2800ooKK

•• Disadvantages:Disadvantages:•• mostly inframostly infra--redred•• glass vacuum envelope & filament both break easilyglass vacuum envelope & filament both break easily•• <15 lm/W luminous (<5% power) efficiency<15 lm/W luminous (<5% power) efficiency•• fire hazard, burnt fingers, maintenancefire hazard, burnt fingers, maintenance

•• Advantages:Advantages:•• Radiant coolingRadiant cooling•• Cheap 0.0005$/lumenCheap 0.0005$/lumen•• klm klm per package!per package!

Illumination MarketsIllumination Markets

Basic disadvantage: no chance to come close to DAYLIGHT = 6500oK

black body spectra

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0.3 0.4 0.5 0.6 0.7 0.8 0.9

po

wer

sp

ectr

a, n

orm

.@60

0 n

m 3000K

4000

5500

6500

7500

µmCourtesy Gerd Mueller LL

Page 6: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

66 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Fluorescent BulbsFluorescent Bulbs

•• Fluorescent = cold light, emitted by phosphors excited by gas diFluorescent = cold light, emitted by phosphors excited by gas discharge.scharge.•• Advantages:Advantages:

•• High efficiency 80+lm/W & High Flux High efficiency 80+lm/W & High Flux klmklm/lamp/lamp•• Moderate cost for large lamps 0.002$/lmModerate cost for large lamps 0.002$/lm

•• Disadvantages:Disadvantages:•• Lifetime short <10,000 hrs resulting in high maintenance.Lifetime short <10,000 hrs resulting in high maintenance.•• Glass vacuum envelope leaks/breaks, ballast noisy.Glass vacuum envelope leaks/breaks, ballast noisy.•• Mercury!!Mercury!!

Illumination MarketsIllumination Markets

Basic Advantage: any color temperature possible by tri-color mixing

0

0.005

0.01

0.015

0.02

0.025

400 450 500 550 600 650 700 750 800nm

rad

. flu

x, a

.u.

0.0

0.2

0.4

0.6

0.8

1.0

1.2

rad

. flu

x, a

.u.black body 3600 K

fluorescent, CCT=3600 K

Ra = 83

Courtesy Gerd Mueller LL

Page 7: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

77 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Illumination MarketsIllumination Markets

Assumptions for using LEDs in lightingAssumptions for using LEDs in lighting

•• LED lamps will be far more expensive than incandescent, halogen LED lamps will be far more expensive than incandescent, halogen or or fluorescent lamps for at least a decade.fluorescent lamps for at least a decade.

•• The expensive LED lamp must pay for itself through lifetime enerThe expensive LED lamp must pay for itself through lifetime energy and gy and maintenance savings.maintenance savings.

•• The lighting industry has spoiled the users with superb color reThe lighting industry has spoiled the users with superb color rendering and ndering and color control.color control.

•• Near term LEDs must dominate monochrome and penetrate white nichNear term LEDs must dominate monochrome and penetrate white niches!es!

Page 8: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

88 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

OutlineOutline

•• Competition in the market for Illumination, Incandescent & FluorCompetition in the market for Illumination, Incandescent & Fluorescent Bulbs.escent Bulbs.

•• LED Technology & metricsLED Technology & metrics

•• Options for making white light from LEDsOptions for making white light from LEDs

•• Lumileds power white LED performanceLumileds power white LED performance

•• Some interesting demosSome interesting demos

High Power White LEDsHigh Power White LEDs

Page 9: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

99 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Tower of Babble?Tower of Babble?

LED MetricsLED Metrics

optical power out / electric power in = Wall-Plug-Efficiency, WPE, (%,W/W)

photons out / electrons in = External Quantum Efficiency, EQE, %

photons internally generated / electrons in = Internal Quantum Efficiency , IQE, %

photons out / photons generated = extraction efficiency, %, ηηext

photon energy / applied voltage (times electron charge) = electrical efficiency, %, ηηel

lumens out / electric power in = luminous efficiency [lm/W]

luminous efficacy, LE [lm/W] = luminous equivalent of the emission spectrum

luminous efficiency = IQE*ηext*ηel*LE

IQE*ηext = EQEEQE*ηel = WPE

WPE*LE = lm/W

Page 10: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1010 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

LED LED SkulduggerySkulduggery

LED MetricsLED Metrics

1) Quoting EQE without Vf or WPE

2) Quoting low duty factor results

3) Quoting WPE without current or current density & total power out.

4) Quoting WPE without temperature

5) Quoting Cd without Flux

Paul’s Top 5 Sins What am I hiding?1) Vf, power efficiency

2) Thermal resistance, heating

3) GaN in particular has strong dependence of WPE on current not much light comes out of a device at very low currents!

4) WPE is strongly dependent on junction temperature forAlInGaP, less so for AlInGaN.

5) Radiation pattern

Page 11: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1111 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Tower of Babble take 2 for white LEDsTower of Babble take 2 for white LEDs

LED MetricsLED Metrics

How well can a source reproduce “natural” colors = Color-Rendering-Index, Ra, %(100 = sunlight, 85 = office, 60 = cabinet/lantern light)

Color Correlated Temperature = CCT, Kelvin (x,y coordinates normal to black body curve)

10,000K

5000K3300K

2500K

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

CIE1931

Planckian locus

tungsten, 2850K

halogen, 3100K

daylight, 6500K

Phosphor Converted LED = PCLED

LED photons pump phosphor which emits secondary, and longer, wavelength of light.

Stoke’s shift = Difference in wavelength between absorbed and emitted photons. Emitted photons

always have longer wavelength, i.e. lower energy!

Page 12: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1212 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

OutlineOutline

•• Competition in the market for Illumination, Incandescent & FluorCompetition in the market for Illumination, Incandescent & Fluorescent Bulbs.escent Bulbs.

•• LED Technology & metricsLED Technology & metrics

•• Options for making white light from LEDsOptions for making white light from LEDs

•• Lumileds power white LED performanceLumileds power white LED performance

•• Some interesting demosSome interesting demos

High Power White LEDsHigh Power White LEDs

Page 13: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1313 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Three methods of Generating LED White LightThree methods of Generating LED White Light

•• Each method has potential strengths!Each method has potential strengths!

White Light from LEDsWhite Light from LEDs

RGB LEDs

Red + Green + Blue LEDs

470 525 590 630 (nm)

Blue Peak

Green Peak

Red Peak

Blue LED+

Yellow phosphor

Binary Complimentary

470 525 590 630 (nm)

Blue LEDSpectrum

Phosphor Emission

Combined Spectrum

UV LED + RGB Phosphor

UV LED + RGB phosphor

410 470 525 590 630 (nm)

UV LEDSpectrum

Phosphor Emission

Combined Spectrum

Page 14: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1414 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Combining Red, Green and Blue LEDsCombining Red, Green and Blue LEDs

•• Advantages:Advantages:•• Long term likely the most efficient!Long term likely the most efficient!•• Dynamic tuning of color temperature possible!Dynamic tuning of color temperature possible!•• Excellent color rendering!Excellent color rendering!•• Very large color Gamut available!Very large color Gamut available!

•• ChallengesChallenges•• Color Feedback required today to account for LED degradation witColor Feedback required today to account for LED degradation with T & t!h T & t!•• Color mixing tricky!Color mixing tricky!•• YellowYellow--Green Gap!Green Gap!

White Light from LEDsWhite Light from LEDs

NTSC

LEDCCFL

EBU

Page 15: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1515 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Lumileds LCD Backlight!Lumileds LCD Backlight!

•• 20 Green, 10 Red, 10 Blue20 Green, 10 Red, 10 Blue Luxeon’sLuxeon’s, ~ 1000 lumens!, ~ 1000 lumens!

•• Today LED Solution has 140% Color Gamut and 120% CCFL power!Today LED Solution has 140% Color Gamut and 120% CCFL power!

Combining Red, Green and Blue LEDsCombining Red, Green and Blue LEDs

Both displays showingBoth displays showingthe same slidethe same slide(red only background)(red only background)via a splittervia a splitter

LED solutionLED solution

CCFL solutionCCFL solution

Page 16: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1616 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

The YellowThe Yellow--Green Gap!Green Gap!

•• Eye Sensitivity Peaks right in the middle of the YellowEye Sensitivity Peaks right in the middle of the Yellow--Green GaP!Green GaP!

White from RGB LEDsWhite from RGB LEDs

450 470 490 510 530 550 570 590 610 630 650 850

Wavelength (nm)

0

10

20

30

40

50

60

Co

nv

er

si

on

E

ff

ic

ie

nc

y

(%

)

VCSELLEDs

Best Laboratory Result

ProductionAverage

Tj = 25ºC

Page 17: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1717 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

UV LED pumped RGB PhosphorsUV LED pumped RGB Phosphors

•• Advantages:Advantages:•• White point determined by phosphors ONLY! (i.e. tolerant to LED White point determined by phosphors ONLY! (i.e. tolerant to LED variation)variation)•• Excellent color rendering possible!Excellent color rendering possible!•• Theoretically “Simple to manufacture!” (Looks like TV or FluoresTheoretically “Simple to manufacture!” (Looks like TV or Fluorescent lamp except cent lamp except

for pump is now UV LED rather than electrons.)for pump is now UV LED rather than electrons.)•• Temperature stability of phosphors. (Can be great!)Temperature stability of phosphors. (Can be great!)

•• DisadvantagesDisadvantages•• Potential for damaging UV light leakage.Potential for damaging UV light leakage.•• Fundamental limits on efficiency due to phosphor conversion effiFundamental limits on efficiency due to phosphor conversion efficiency, Stokes ciency, Stokes

shift, self absorption,…shift, self absorption,…

•• ChallengesChallenges•• None available yet!?None available yet!?•• Efficient Blue LED pumped phosphor not available yet?!Efficient Blue LED pumped phosphor not available yet?!•• Color uniformity with angle!Color uniformity with angle!•• Packaging must be robust to UV exposure.Packaging must be robust to UV exposure.•• Temperature stability of phosphors. (Great phosphors not availabTemperature stability of phosphors. (Great phosphors not available in all colors!)le in all colors!)

White Light from LEDsWhite Light from LEDs

Page 18: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1818 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

UV LED must be >2x Green LED WPE for same lm/W!UV LED must be >2x Green LED WPE for same lm/W!

•• Downshift in color causes fundamental energy loss.Downshift in color causes fundamental energy loss.

•• Scattering in phosphor + absorption in package (inc. phosphor) rScattering in phosphor + absorption in package (inc. phosphor) reduces extraction educes extraction efficiency! Today’s best package efficiency is ~50% for Blue +efficiency! Today’s best package efficiency is ~50% for Blue + Yellow phosphor, Yellow phosphor, UV + RGB phosphor likely to be even worse!UV + RGB phosphor likely to be even worse!

UV LED pumped RGB PhosphorsUV LED pumped RGB Phosphors

0%10%20%30%40%50%60%70%80%90%

100%

370 380 390 400 410 420 430

UV Pump Wavelength (nm)

Po

wer

Co

nve

rsio

n (

%)

Red 630nmBlue 460nmGreen 540nmWhite White + PkgAssuming 50% pkg. Efficiency!

Page 19: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

1919 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

White from Blue LED + Phosphor(s)White from Blue LED + Phosphor(s)

•• Advantages:Advantages:•• Simple and single Yellow phosphor versions available today!Simple and single Yellow phosphor versions available today!•• Decent color rendering (Ra = 75 for Blue LED + Yellow Phosphor)Decent color rendering (Ra = 75 for Blue LED + Yellow Phosphor)•• Temperature stability of phosphors. (Can be great!)Temperature stability of phosphors. (Can be great!)

•• DisadvantagesDisadvantages•• Limits on efficiency due to phosphor conversion efficiency, StokLimits on efficiency due to phosphor conversion efficiency, Stokes shift, self es shift, self

absorption,…absorption,…•• Better color rendering (i.e. multi phosphor comes at cost of effBetter color rendering (i.e. multi phosphor comes at cost of efficiency)iciency)

•• ChallengesChallenges•• Temperature stability of phosphors. (Great phosphors not availabTemperature stability of phosphors. (Great phosphors not available in all colors)le in all colors)•• Color uniformity vs. angleColor uniformity vs. angle•• Multi phosphor versions to improve color renderingMulti phosphor versions to improve color rendering

White Light from LEDsWhite Light from LEDs

Page 20: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2020 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Today, PC LEDs are in the 20Today, PC LEDs are in the 20--30lm/W range!30lm/W range!

•• TodaysTodays white LEDs are in the ~20white LEDs are in the ~20--30lm/W range!30lm/W range!

White from Blue LED + Phosphor(s)White from Blue LED + Phosphor(s)

0

10

20

30

40

50

60

70

400 500 600 700 800nm

CCT=4000K, Ra=75

640

620630

600

590

540

530

520

510

500

460

470

480

490

450 nm

10,000K

5000K

3300K

2500K

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

LED, T = 25C

LED,T = 105C

YAG:Ce

Planckian locus

CIE1931

Ce3+ doped garnet family, e.g.(Y,Gd)3Al5O12

Combined with the same LED, Ce3+

phosphors hit the Planckian at different color temperatures:

Ra = 75 is not great (good FL has 83)but it is OK for some applications.

Page 21: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2121 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Color Uniformity can be good for PC White!Color Uniformity can be good for PC White!

•• CCT uniformity of 50CCT uniformity of 50--100K is sufficient for high quality illumination.100K is sufficient for high quality illumination.

White from Blue LED + Phosphor(s)White from Blue LED + Phosphor(s)

3000320034003600380040004200440046004800500052005400

-85 -75 -65 -55 -45 -35 -25 -15 -5 5 15 25 35 45 55 65 75 85

Theta (degrees)

CC

T (K

)

800K

80K

Page 22: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2222 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Progress on Temperature stability of PhosphorsProgress on Temperature stability of Phosphors

White from Blue LED + Phosphor(s)White from Blue LED + Phosphor(s)

0

200000

400000

600000

800000

1000000

1200000

400 500 600 700 800

25

50

100

120

150

200novel phosphors with improved color specs emerge; in this case using a Ce3+ - Pr3+ transfer of excitation energy and yielding more temperature stable behavior

(Y,Gd)AG, 4 mol% Ce

0

20

40

60

80

100

25 50 75 100 125 150

Temperature, C

I(T

)/I(

25C

), %

[Gd]0%

25

5075

measured on powders (Y,Gd)AG:Ce

0

200000

400000

600000

800000

1000000

1200000

400 450 500 550 600 650 700 750 800

nm

rad

ian

ce u

nd

er 4

60 n

m e

xcit

atio

n

25 C

50

100

120

150

200

Page 23: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2323 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

The 2The 2--phosphorphosphor--converted LED converted LED –– 2pcLED2pcLED

White from Blue LED + Phosphor(s)White from Blue LED + Phosphor(s)

490

480

470

460

500

510

520

530

540

590

600

SrS:Eu

630620

640

TG:Eu

7118 7193

8206

61010,000K

5000K

3300K2500K

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

HP LED, T = 25CHP LED,T = 105CPlanckian locusPhosphorsCIE1931Series15

combospec

0.00

0.50

1.00

1.50

2.00

400 500 600 700 800

Ra = 92

combospec

0.000.200.400.600.801.001.201.401.60

400 500 600 700 800

Ra = 92

1 LED + 2 phosphors Adding green and red to the blue of the LED opens a huge color gamut and allows for de-luxe white of any color temperature – our best choice• SrGa2S4:Eu2+ - green• SrS:Eu2+ - red

The dipole-allowed 5d-4f transitions of Ce3+ and Eu2+

are uniquely suited for color converters: high absorption, small Stoke’s shift

Page 24: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2424 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

All three white LED technologies share All three white LED technologies share ThreeThreechallenges!challenges!

11 Maximize efficiency in lm/WMaximize efficiency in lm/W

22 Maximize flux density in lm/packageMaximize flux density in lm/package

33 And of coarse reduce cost $/lmAnd of coarse reduce cost $/lm

White Light from LEDsWhite Light from LEDs

90 lm/bulb6 lm/W0.005 $/lm

145 lm/bulb50 lm/W0.02 $/lm

475 lm/bulb10 lm/W0.01 $/lm

Page 25: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2525 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

OutlineOutline

•• Competition in the market for Illumination, Incandescent & FluorCompetition in the market for Illumination, Incandescent & Fluorescent Bulbs.escent Bulbs.

•• LED Technology & metricsLED Technology & metrics

•• Options for making white light from LEDsOptions for making white light from LEDs

•• Lumileds power white LED performanceLumileds power white LED performance

•• Some interesting demosSome interesting demos

High Power White LEDsHigh Power White LEDs

Page 26: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2626 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Cathode Lead

LED Chip

Anode Lead

Reflector Cup

Epoxy Dome Lens

Gold Wire Bond

n pad

p pad

semitransparentcontact

Limitations of conventional 5mm Limitations of conventional 5mm IndicatorIndicator LED lampsLED lamps

•• Very high thermal resistance, >200°C/W,Very high thermal resistance, >200°C/W,

•• Epoxy limited to <<120°C due to thermal yellowing,Epoxy limited to <<120°C due to thermal yellowing,

•• Light utilization efficiency is low.Light utilization efficiency is low.

Junction area ~ 0.06mm2

High Power White LEDsHigh Power White LEDs

Page 27: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2727 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

LuxeonLuxeon™™ approachapproachDie designDie design•• Large area die for high power capability,Large area die for high power capability,

•• Electrode design for low spreading resistance,Electrode design for low spreading resistance,

•• FlipFlip--chip configuration;chip configuration;•• high extraction efficiency,high extraction efficiency,•• low thermal resistance,low thermal resistance,•• ability to integrate electronics.ability to integrate electronics.

Package designPackage design•• Low thermal resistance package,Low thermal resistance package,

•• Stable, soft gel inner Stable, soft gel inner encapsulantencapsulant,,

•• Controlled radiation pattern and efficient optics.Controlled radiation pattern and efficient optics.

System designSystem design•• Low thermal resistance board design,Low thermal resistance board design,

•• Efficient secondary optical elements.Efficient secondary optical elements.

High Power White LEDsHigh Power White LEDs

Page 28: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2828 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Lumileds LuxeonLumileds LuxeonTMTM Power LED EfficiencyPower LED Efficiency

•• Leading the charge into Solid State IlluminationLeading the charge into Solid State Illumination

High Power White LEDsHigh Power White LEDs

350mA If lm/W lm/LED lm/W lm/LEDRed 44 43 50 50Red-Orange 55 54 65 65Amber 36 36 44 44Green 25 30 50 55Blue 11 14 15 20White 18 22 30 36

Production Typical R&D Demonstrations

Page 29: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

2929 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

0.001

0.01

0.1

1

10

100

1000

1960 1970 1980 1990 2000 2010

Year

Flux

/Pac

kage

(lum

ens)

Indicator LEDs

Luxeon TM

Haitz’s Haitz’s Law for LED FluxLaw for LED Flux

•• LED Flux per package has doubled every 18LED Flux per package has doubled every 18--24 months for 30+ Years!!24 months for 30+ Years!!

•• 19651965 Moore’sMoore’s Law “# of Transistors/chip will double every 18Law “# of Transistors/chip will double every 18--24 months!”24 months!”

LED TechnologyLED Technology

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3030 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

0.01

0.1

1

10

100

1000

0.1 1 10 100 1000 10000

Power input (mW)

Flu

x o

utp

ut

(lm

)

Lumileds LuxeonLumileds LuxeonTMTM Series A & B LEDsSeries A & B LEDs

•• First ever White LED > 100lm!! (100.2lm and 15lm/W to boot!!)First ever White LED > 100lm!! (100.2lm and 15lm/W to boot!!)

High Power White LEDsHigh Power White LEDs

Indicator White LED

Luxeon Series A White LED

Luxeon Series B White LED

All data AC 1%DF & 25C case

Page 31: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3131 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Lumileds 100 lumen Club!Lumileds 100 lumen Club!

•• These are the only LEDs that approach “Illumination” flux!These are the only LEDs that approach “Illumination” flux!

High Power White LEDsHigh Power White LEDs

Red 1000 105 February-01Amber 700 110 December-99Green 700 108 March-01White 1870 100.2 July-01White 1400 >110 1-Sep

Page 32: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3232 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

What about Radiometric Power?!What about Radiometric Power?!

•• State of the art 400nm indicator LEDs provide 15mW of power. State of the art 400nm indicator LEDs provide 15mW of power.

•• How much power can a Luxeon part generate? :How much power can a Luxeon part generate? :--))

High Power White LEDsHigh Power White LEDs

If (mA) W/LED DateDeep Blue 430nm 1400 >1.0 July-01Dan Steigerwald

Talk 4445-19 08:30 8/1/2001

Page 33: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3333 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Lumileds LuxeonLumileds LuxeonTMTM Series B Cyan LEDSeries B Cyan LED

•• Single Series B Cyan LED can replace an 80W bulb in an 8” traffiSingle Series B Cyan LED can replace an 80W bulb in an 8” traffic ball!c ball!

High Power White LEDsHigh Power White LEDs

130 lm/bulb30 lm/W0.20? $/lm

Page 34: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3434 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Lumileds LuxeonLumileds LuxeonTMTM RingRing

•• Fixture design by Philips Lighting and Lumileds.Fixture design by Philips Lighting and Lumileds.

•• 12 12 Luxeon’sLuxeon’s, ~240 lumens. Ring available , ~240 lumens. Ring available Now!Now!

High Power White LEDsHigh Power White LEDs

Page 35: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3535 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

OutlineOutline

•• Competition in the market for Illumination, Incandescent & FluorCompetition in the market for Illumination, Incandescent & Fluorescent Bulbs.escent Bulbs.

•• LED Technology and metricsLED Technology and metrics

•• Comparison of options for making white LEDsComparison of options for making white LEDs

•• Lumileds power white LED performanceLumileds power white LED performance

•• Some interesting demosSome interesting demos

High Power White LEDsHigh Power White LEDs

Page 36: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3636 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Evolution of LED Package TechnologyEvolution of LED Package Technology

•• Power LEDs can handle ~50x power of an Indicator LED!Power LEDs can handle ~50x power of an Indicator LED!

High Power White LEDsHigh Power White LEDs

Pmax~0.6-4.0W9-14 K/W

1998Pmax~0.2-0.4W

50 K/W1994

Pmax~0.1W150-200 K/W

1970

1962 Standard 5mm Lamp

LumiLeds SnapLEDTM

LumiLeds LuxeonTM

Indicator LED

Indicator LEDFirst Packaged LED

First Power LED

Today’s Power LED

Page 37: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3737 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Lumileds LuxeonLumileds LuxeonTMTM Power LEDPower LED

•• Packages designed to handle 1Packages designed to handle 1--5W!5W!

High Power White LEDsHigh Power White LEDs

HighHigh--Power Package:Power Package:

Improved thermal propertiesImproved thermal properties

Heat sink body with good thermal interfaceHeat sink body with good thermal interface

Soft gel innerSoft gel inner encapsulantencapsulant

Including power Including power AlInGaNAlInGaN or or AlInGaPAlInGaP or or Phosphor Converted AlInGaN Chip:Phosphor Converted AlInGaN Chip:

θθjcjc~ 12°C/W~ 12°C/W

High optical efficiency > 95%High optical efficiency > 95%

Page 38: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3838 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Potential Power Savings vs. Traditional LightingPotential Power Savings vs. Traditional Lighting

•• TodaysTodays white LEDs are in the ~20white LEDs are in the ~20--30lm/W range, but still low flux!30lm/W range, but still low flux!

High Power White LEDsHigh Power White LEDs

0

20

40

60

80

100

0 25 50 75 100 125 150 175 200 225 250

LED Efficiency (lm/W)

Pow

er S

aved

(%

)

Incandescent

Halogen

CFL

Fluorescent

Page 39: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

3939 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Indicator LEDs vs. Power LEDsIndicator LEDs vs. Power LEDs

•• Indicator LEDs have output powers < ~50mW and Thermal resistancIndicator LEDs have output powers < ~50mW and Thermal resistances > 50K/Wes > 50K/W

LED TechnologyLED Technology

10-3 10-2 10-1 100 10110-4

10-3

10-2

10-1

100

Operating Point

Operating PointInGaN LEDsλ ~450 nm

"5 mm" LED

Power LED

Out

put

Powe

r (W

)

Input Power (W)

Page 40: High Power White LED Technology for Solid State Lighting ...pedro/optoele/LEDs/LEDilumination.pdf · High Power White LED Technology ... High Power White LEDs. ... 10 Blue Luxeon’s,

4040 Copyright (c) Copyright (c) Lumileds Lumileds Lighting LLC CompanyLighting LLC Company

Indicator LEDs vs. Power LuxeonIndicator LEDs vs. Power LuxeonTMTM LEDs!LEDs!

•• Luxeon’s Luxeon’s are designed for low thermal resistance & high current density!are designed for low thermal resistance & high current density!

High Power White LEDsHigh Power White LEDs

0 50 100 150 200

0

4

8

12

16

20 InGaN LEDsλ

d ~530 nm

"5 mm" LED

Power LED

Wal

l Plu

g Ef

fici

ency

(%

)

Current Density (A/cm2)

0 50 100 150 200

0

20

40

60

80

100

120 InGaN LEDsλ

d ~530 nm

"5 mm" LED

Power LED

Current Density (A/cm2)

Lum

inou

s Fl

ux (

lm)


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