Touchscreen Technology 2

8/9/2019 Touchscreen Technology 2

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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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