Post on 30-May-2018
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PRESENTATION BY
B.UMA(2008-2012)
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INTRODUCTION TO THE TECHNOLOGYINTRODUCTION TO THE TECHNOLOGY
HOW IT WORKS ?HOW IT WORKS ?
TOUCH SCREEN DIVERSITYTOUCH SCREEN DIVERSITY
CONTROLERS USEDCONTROLERS USED
APPLICATIONSAPPLICATIONS
CLOSING THOUGHTSCLOSING THOUGHTS
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INTRODUCINGTHETECHNOLOGYA touch screen is an input device that allows users to
operate a PC by simply touching the display screen.
The display screen has a sensitive glass overlay placed
on it and we could give the desired input by touching it .
A touch screen is based on CRT (Cathode Ray Tube)technology, that accepts direct onscreen input.
The ability for direct onscreen input is facil itated by anexternal (light pen) or an internal device (touch overlayand controller) .
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HOW DOESA TOUCHSCREENWORK?
Main touch screen components:Main touch screen components:
Touch sensorController
Software driver
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TOUCH SENSORA touch screen sensor is a clear glass panel with
a touch responsive surface which is placed overa display screen so that the responsive area ofthe panel covers the viewable area of the display
screen.
The sensor generally has an electrical current orsignal going through it and touching the screen
causes a voltage or signal change. This voltagechange is used to determine the location of thetouch to the screen
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CONTROLLER The controller is a
small PC card that
connects between the
touch sensor and thePC. It takes
information from the
touch sensor and
translates it intoinformation that PC
can understand.
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SOFTWARE DRIVER
The driver is a software that allows the touch
screen and computer to work together. It tells the
operating system how to interpret the touch eventinformation that is sent from the controller.
Most touch screen drivers today are a mouse-
emulation type driver. This makes touching thescreen the same as clicking your mouse at the same
location on the screen.
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TOUCHSCREEN DIVERSITYResist i ve Touch screen
Surface wave Touch screen
Capaci t i ve Touch screen*Surface capaci t i ve
*Projected capaci t i ve
Near Field Imaging Touch screen
Infrared Touch screen
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RESISTIVETOUCHSCREEN1. Polyester Film .
2. Top Resistive Layer.
3. Conductive Transparent Metal Coating.4. Bottom Resistive Layer .
5. Insulating Dots .
6. Glass Substrate
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Continued Resistive touch screen monitor is composed of a
flexible top layer and a rigid bottom layer separated by
insulating dots, attached to a touch screen controller.
The inside surface of each of the two layers is coated
with a transparent metal oxide coating Pressing the f lexible top sheet creates electrical contact
between the resistive layers, producing a switch closingin the circuit.
The controller gets the alternating voltages between the
two layers and converts them into the digital X and Ycoordinates of the activated area.
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VS20UA CONTROLLERSupply Vol tage
5.0V DC
Maximum Current20mA (Pick)
Resolution
12-bit
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SURFACE WAVE TECHNOLOGY It has a transmitting and receiving transducers for both
the X and Y axes.
The touchscreen controller sends a 5 MHz electrical
signal to the transmitting transducer, which convertsthe signal into ultrasonic waves within the glass.
These waves are directed across the front surface of thetouchscreen by an array of ref lectors.
Reflectors on the opposite side gather and direct thewaves to the receiving transducer, which reconvertsthem into an electrical signala digital map of thetouchscreen
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Continued
When you touch the screen, you absorb a portion ofthe wave traveling across it. The received signal isthen compared to the stored digital map, the changerecognized, and a coordinate calculated. . Thedigit ized coordinates are transmitted to thecomputer for processing.
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2701RSU CONTROLLERVoltaze
+5 VDC
Baud Rate9600 (default) and 19200
Touch Resolut ion
12bit, size independent
Conversion Time
10 ms per coordinate set
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CAPACITIVETOUCHSCREENS
Surface Capacitive
It has a an uniform conductive coating on aglass panel.
During operation, electrodes around the panel'sedge evenly distribute a low voltage across theconductive layer & creates an uniform electricfield.
A finger touch draws current from each corner.
Then the controller measures the ratio of thecurrent flow from the corners and calculatesthe touch location
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5000 RSU SERIAL CONTROLLERSupply Vol tage :+5 V DC or +12V
Baud Rate
9600 (default) and19200
Touch Resolut ion12bit, size independent.
Conversion TimeApproximately 15 ms per
coordinate set
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Projected Capacitive
Touch screen3layers:-front and
back protective glass
provides optical and
strength enhancement
options & middle
layer consists of a
laminated sensor grid
of micro-fine wires
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Continued
During a touch,capacitance formsbetween thefinger and thesensor grid.
The embeddedserial controller inthe touch screencalculates touch
locationcoordinates andtransmits them tothe computer forprocessing.
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APPLICATIONS..Publ ic Information Displays:::Tourism displays, Trade show display
Customer Self-Services:::
Stores, Restaurants, ATMs, Airline ticketterminals and Transportation hubs.
More uses...Digital jukeboxes, Computerized gaming,Student Registration systems, Multimediasoftwares , Scient ific applications etc.
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Pros & ConsDirect pointing to the
objects.
Fast
Finger or pen is usable(No cable required)
No keyboard necessary
Suited to: novices,
application forinformation retrieval etc
Low precision by using
finger
User has to sit or stand
closer to the screenThe screen may be
covered more by usinghand
No direct activation tothe selected function
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CLOSING THOUGHTS
Though the touch screen technology contains somelimitations its very user friendly, fast, accurate, easyfor the novices & fun to operate. It has been widely
accepted. And now by just modifying a litt le it canreplace the mouse and key board completely innear future.
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REFERENCEs:HTTP:/ / w w w .i-t e c h c o mpa ny .c o m/ t o uc h s c r e e n.ht mlh t t p:/ / e n.wi k ip e di a .o r g / w ik i / t o uc h sc r e e n
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A NYQUERIES?
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