TOUCH SCREEN

S.AMRISH Department Of Computer Engineering

Suguna Polytechnic CollegeCoimbatore

Introduction

Evolution Of Touch Screen

Types Of Touch Screen

IPOD Touch Screen

IntroductionA Touchscreen is an electronic visual display that can detect the presence and location of a touch within the display areaIt is an Input device that allows users to operate a PC by simply touching the display screenA touch screen is based on CRT (Cathode Ray Tube) technology, SAW (Surface Acoustic Wave) technology, that accepts direct onscreen input. The ability for direct onscreen input is facilitated by an external (light pen) or an internal device (touch overlay and controller) .

In 1971, the first "touch sensor" was developed by Doctor Sam Hurst (founder of  Elographics) while he was an instructor at the University of Kentucky.

In 1974, the first true touch screen incorporating a transparent surface came on the scene developed by Sam Hurst and Elographics. In 1977, Elographics developed and patented five-wire resistive technology, the most popular touch screen technology in use today.

Evolution Of Touch Screen

How Does a Touchscreen Work?A basic touchscreen has three main components:

Touch Sensor, ControllerSoftware Driver.

The touchscreen is an input device, so it needs to be combined with a display and a PC or other device to Make a complete touch input system.

Touch SensorA touch screen sensor is a clear glass

panel with a touch responsive surface.

The sensor generally has an electrical current or signal going through it and touching the screen causes a voltage or signal change.

This voltage change is used to determine the location of the touch to the screen.

CONTROLLERThe controller is a small PC card that connects between the touch sensor and the PC. It takes information from the touch sensor and translates it into information that PC can understand.

The controller determines what type of interface/connection you will need on the PC.

Controllers are available that can connect to a Serial/COM port (PC) or to a USB port (PC or Macintosh). Specialized controllers are also available that work with DVD players and other devices.

Software DriverThe driver is a software that allows the touch screen and computer to work together. It tells the operating 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 the screen the same as clicking your mouse at the same location on the screen.

This allows the touchscreen to work with existing software and screen driver.

Touch WareTSHARCCrystal TouchELOUPD Driver 3.5.18Microcal 7.1

TOUCH SCREEN DIVERSITYResistive Touch screenSurface wave Touch screenCapacitive Touch screen

Surface capacitiveProjected capacitive

Near Field Imaging Touch screenInfrared Touch screen

Resistive TouchscreensResistive touch screen monitors are usually made up of a flexible top layer and a rigid bottom layer. The resistive touch screen monitors are very durable and are not easily contaminated with items that may interfere with the acoustic waves. Bottom Resistive Layer .Insulating Dots .Glass Substrate

CAPACITIVE

A capacitive touch screen panel is coated with a material, typically indium tin oxide that conducts a continuous electrical current across the sensor.

The sensor therefore exhibits a precisely controlled field of stored electrons in both the horizontal and vertical axes - it achieves capacitance.

SAW TECHNOLOGYSurface acoustic wave (SAW) technology uses ultrasonic waves that pass over the touch screen panel.

When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing.

Infrared TouchscreenAn infrared (IR) touch screen panel employs one of two very different methods. One method uses thermal induced changes of the surface resistance. This method is sometimes slow and requires warm hands. Another method is an array of vertical and horizontal IR sensors that detect the interruption of a modulated light beam near the surface of the screen. IR touch screens have the most durable surfaces and are used in many military applications that require a touch panel display.

IPOD Touch ScreensiPod touch apart from other iPod models -- other than the latest nano -- is its touch-screen interface. When you touch the screen, the iPod's circuitry detects the presence of your finger. It keeps track of how many fingers you have on the screen and where you move them.

Working Of Ipod & Iphone TouchScreens

Top polyester coated with a transparent metallic conductive coating on the bottom

Adhesive layer on the backside of the glass for mounting.

Glass layer coated with a transparent metallic conductive coating on the top

Adhesive spacer

CONSTRUCTION OF TOUCH SCREEN

How to touch the Touch Screen

Key Board

Mouse

Key Pad

Tracer

Advantages of Touchscreen when Compared With Other Input

Devices

1.No sp

ecial c

ommands to le

arn

2.No use

of keyb

oards etc.

3.Entering w

rong inform

ation is

imposs

ible

4.No fe

ar of d

amage or lost

of loose

hardware pieces

Kiosk SystemsA Kiosk ( Pronounced Key-osk) is a computer based terminal or display that is used to provide information or services typically in public place kiosk systems

INFORMATION DIRECTORIES CUSTOMER SELF – SERVICE TERMINAL ELECTRONIC CATALOGUE TOURISM GUIDES RETAIL AND RESTAURANT SYSTEMS CUSTOMER SELF SERVICE CONTROL AND AUTOMATION SYSTEMS COMPUTER BASED TRAINING ASSISTIVE TECHNOLOGY

APPLICATIONS

Touch Screens are Used in :

PUBLIC INFORMATION DISPLAYSTourism displays, Trade show display

CUSTOMER SELF SERVICESStores, Restaurants, ATMs, Airline ticket terminals

Application of Touch Screens

QUERIES

CONCLUSION

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