STUDY OF TOUCH SCREEN TECHNOLOGY

Presented By : Indranee Shyam (EC/12/06)

Sudesna Mukherjee (EC/12/19)

Susmita Mahato (EC/12/21)

Guided By : Mr. SYED

SAMSHER ALI

(H.O.D of ECE Deptt.)

CONTENTS1) Why Touch Screen ?

2) Block Diagram

3) Major Components

4) Types of Touch Screen

5) Comparison

6) Applications

7) Closing Thoughts

Why Touch Screen? Locates the coordinates of a user’s touch

within display area. Refers to touching the display of the device

with a finger . Based either on LCD (Liquid Crystal

Display) or CRT(Cathode Ray Tube) technology that accepts direct onscreen input.

The father of touch screen technology is Dr. Samuel Hurst ,in 1971,which is called “ELO graph”.

The Nokia 7710 is the first touch screen mobile phone.

Block Diagram

Major Components Touch Sensor : Glass panel with a touch responsive surface having an electrical current or

signal going through it and causes a voltage or signal change which is used to determine the location.

Controller : Small PC card connects between the touch sensor and the PC. Software Driver : Software allows the touch screen and computer to work together.

Types of Touchscreen Technologies

Resistive Capacitive Surface Acoustic Wave Infrared / Optical Touch

Screen

Four different technologies used to make touch screens today:

Resistive Touchscreen

1) Composed of two layers of conductive material which is coated with a transparent metal oxide coating of Indium Tin Oxide (ITO)

2) Uses both the upper and lower layers in the touch screen "sandwich" to determine the X and Y coordinates.

.

Capacitive Touch Technology

1) Glass panel with conductive layer (Indium Tin Oxide).

2) When the panel is touched, a small amount of charge is drawn to the point of contact .

3) Two types :

a) Surface

b) Projected

Surface Acoustic Wave Touch Screen

1) Surface Acoustic Wave (SAW) technology.

2) Ultrasonic waves across the surface.

3) Piezoelectric transducers and receivers along the sides of the monitor’s glass plate to create an invisible grid of ultrasonic waves on the surface.

Infrared / Optical Touch Screen

1) Infrared monitors use IR emitters and receivers to create an invisible grid of light beams.

2) Uses infrared LEDs and matching photodetectors across the screen.

3) When an object interrupt the invisible infrared light beam, the sensors are able to locate the touch point.

Touch Screen Technology Comparison ChartResistive Infrared SAW Capacitive

Touch Resolution

High High Average High

Clarity Average Good Good Good

Operation Finger or Stylus Finger or Stylus Finger or Soft-tipped Stylus

Finger only

Durability Can be Damaged by Sharp Objects

Highly Durable Susceptible to Dirt and Moisture

Highly durable

Today’s Touch Screen tech put the world at our fingertips

Present uses : • Retails & Restaurants • ATMs , Ticket Booking , Registration system• Smart Phones , digital camera , etc…

Future uses:• Advanced hand sensing.. • Digital display of human DNA structure• Motion Sensor , etc ....

Drawback Of Touch Technology

Become less-visible. Scratches on the screen that may cause

malfunction in some cases. Unlike push-button and mouse, users will not feel

"click" when a user input a touch screen, thus operation may become clumsy sometimes.

CLOSING THOUGHTS User friendly , fast ,accurate , easy and fun to operate . Information more easily accessible. Widely accepted and modifying a little it can replace

the mouse and keyboard completely in near future.

References Beyers , Tim "Innovation Series: Touch screen

Technology". Larry K. Baxter (1996). “Capacitive Sensors”. John Wiley

and Sons. http://en.wikipedia.org/wiki/Touchscreen http://www.touchscreens.com/intro-anatomy.html http://www.tvielectronics.com/Touch_Screen.html http://www.slideshare.com/Touch_Screen Technology.html