PRESENTED BY:

NIKHIL LOSALKA(30)PANKAJ CHOWDHURY(31)PRITAM BOSE(33)

TOUCH SCREEN TECHNOLOGY

INTRODUCTION

Most sophisticated computer access technology.

Detect the presence and location of a touch.

Eliminates the need for the mouse and keyboard.

HISTORY

Emerged in the second half of the 1960s.

In 1971, Sam Hurst, invented first touch sensor

In 1977 , "touchscreen."

1) SURFACE ACOUSTIC WAVE:

Uses ultrasonic waves.

It is based on sending waves across a clear glass panel with a series of transducers and reflectors.

Disadvantages

Touched by finger, gloved hand, or soft-tip stylus.

Not completely sealable.

TECHNOLOGIES2) RESISTIVE:

Composed of two thin, metallic, conductive layers.

Change in current is registered as touch event.

DISADVANTAGES

Offer only 75% clarity.

The layer can be damaged.

Cannot press hand down on the screen while writing.

3) CAPACITIVE:

Consists of insulator coated with a transparent conductor.

Touching results in a distortion of the electrostatic field.

4) INFRARED:

It employs one of two very different methodologies.

Use an array of infrared light-emitting diodes.

5) Strain gauge :

The screen is spring-mounted on the four corners.

Used to determine deflection when the screen is touched.

6) Optical imaging:

Two or more image sensors are placed around the edges of the screen.

Revolutionizes the way we interface with computer technology.

7) Dispersive signal technology:Chemically-strengthened glass substrate

with piezos mounted on each corner.

Determines position by pinpointing the source of “bending waves”.

Comparison of touchscreen technologies

Technology

4-Wire SAW 5-Wire Infrared Capacitive

Durability:5 year 5 Year 3 Year 3 Year 2 Year

Stability:High Higher High High Ok

Touch:Anything Finger/Pen Anything Sharp Conductive

Response time:

<10ms 10ms <15ms <20ms <15ms

Monitor option:

CRT CRT CRT or LCD CRT or LCD CRT or LCD

Waterproof:

Good Ok Good Ok Good

CONSTRUCTION

Three main components:

1) Touch Sensor

Touch response surface.

It is a clear glass panel.

2) Controller

Interface between a touch screen sensor and the device the sensor is used to control.

Determines what type of interface/connection.

3) Software Driver

Software update for the PC system.

Allows the touchscreen and computer to work together.

APPLICATIONS

Public Information Displays.

Retail and Restaurant Systems .

Customer Self-Service.

Control and Automation Systems.

Computer Based Training.

Assistive Technology.

THANK YOU..!!