Uday Touchscreen - Copy

8/8/2019 Uday Touchscreen - Copy

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INTRODUCTION TO THE TECHNOLOGY

HOW IT WORKS ?

TOUCH SCREEN DIVERSITY

CONTROLERS USED

APPLICATIONS

CLOSING THOUGHTS



Touch screen is an input device that allows users tooperate a PC by simply touching the display screen.

The display screen has a sensitive glass overlay placedon 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 facilitated by an

external (light pen) or an internal device (touch overlayand controller).



Main touch screen components:Main touch screen components: Touch sensor

Controller

Software driver

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A touch screen sensor is a clear glass panel witha touch responsive surface which is placed over adisplay screen so that the responsive area of thepanel covers the viewable area of the display

screen.

The sensor generally has an electrical current orsignal going through it and touching the screencauses a voltage or signal change. This voltagechange is used to determine the location of thetouch to the screen.

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The controller is asmall PC card thatconnects between

the touch sensor andthe PC. It takesinformation from thetouch sensor andtranslates it into

information that PCcan understand.



The driver is a software that allows the touchscreen and computer to work together. It tells theoperating system how to interpret the touch event

information 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 samelocation on the screen.



Resistive touch screen

Surface wave touch screen

Capacitive touch screen

*Surface capacitive*Projected capacitive

Near Field Imaging touch screen

Infrared touch screen



1. Polyester

Film

2. Top Resistive

Layer

RESISTIVE TOUCH SCREENRESISTIVE TOUCH SCREEN

3. Conductive

Transparent

Metal Coating

. Insulating

Dots

6. Glass

Substrate



Resistive touch screen monitor is composed of aflexible top layer and a rigid bottom layerseparated by insulating dots, attached to a touchscreen controller.

The inside surface of each of the two layers iscoated with a transparent metal oxide coating

Pressing the flexible top sheet createselectrical contact between the resistive layers,producing a switch closing in the circuit.

The controller gets the alternating voltagesbetween the two layers and converts them intothe digital X and Y coordinates of the activatedarea.



Supply Voltage5.0V DC

MaximumCurrent20mA (Pick)

Resolution12-bit



It has a transmitting and receiving transducers forboth the X and Y axes.

The touch screen controller sends a 5 MHz electricalsignal to the transmitting transducer, which converts

the signal into ultrasonic waves within the glass.

These waves are directed across the front surfaceof the touch screen by an array of reflectors.

Reflectors on the opposite side gather and direct thewaves to the receiving transducer, which reconvertsthem into an electrical signal³a digital map of thetouch screen.



When you touch the screen, you absorb a

portion of the wave traveling across it. Thereceived signal is then compared to thestored digital map, the change recognized,and a coordinate calculated. The digitizedcoordinates are transmitted to the

computer for processing.



Voltaze+5 VDC

Baud Rate

9600 (default) and19200

Touch Resolution12bit, size independent

Conversion Time10 ms per coordinate

set



It has a an uniform conductive coating on a glasspanel.

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 calculates thetouch location



Supply Voltage :+5 V DC or +12V

Baud Rate:9600 (default) and

19200

Touch Resolution:12bit, sizeindependent.

Conversion Time:Approximately 15 msper coordinate set.



3layers:- front and

back protective glass

provides optical and

strength enhancementoptions & middle

layer consists of a

laminated sensor grid

of micro-fine wires



During a touch,capacitanceforms betweenthe finger andthe sensor grid.

The embeddedserial controllerin the touchscreen calculatestouch locationcoordinates andtransmits themto the computerfor processing.



Public Information Displays:::Public Information Displays:::Tourism displays, Trade show display.

Customer SelfCustomer Self--Services:::Services:::Stores, Restaurants, AT Ms, Airline ticketterminals and Transportation hubs.

More uses...More uses...Digital jukeboxes, Computerized gaming, Student

Registration systems, Multimedia softwares,Scientific applications etc.



Direct pointing tothe objects.

Fast.

Finger or pen isusable

(No cable required).

No keyboardnecessary.

Suited to: novices,application for

information retrievaletc.

Low precision byusing finger.

User has to sit orstand closer to the

screen.

The screen may becovered more by

using hand.

No direct activationto the selected

function.

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Though the touch screen technology contains somelimitations it·s very user friendly, fast, accurate,easy for the novices & fun to operate. It hasbeen widely accepted. And now by just modifying

a little it can replace the mouse and key boardcompletely in near future.



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Uday Touchscreen - Copy

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