Touch screen technology

1. TOUCH SCREEN TECHNOLOGY
Name : K.Ravi Chandu
Branch: ECE-C
Roll No: 20895A0420
Co-ordinator:
(Dr.Khaja Mujeebuddin Quadry)
(Mr.M Rajan)

2. ❑CONTENTS
◈Introduction
◈History and Development
◈Components of Touch screen
◈Types of Touch Screens
◈Advantages and Disadvantages
◈Applications
◈Future scope
◈Conclusion
◈Reference

3. ❑INTRODUCTION
 A touch screen is a computer display
screen that is Sensitive to human
touch, allowing a user to interact with
the computer by touching pictures or
words on the screen.
 A touch screen is an input device that
allows users to operate a PC by simply
touching the display screen which has a
sensitive glass overlay placed on it .
 A touch screen accepts direct onscreen
inputs.

4. ❑History and Development
 In 1971,the first "touch sensor" was
developed by Docter Sam Hurst(founder of
Elography),while he was an instructor at
the University of Kentucky.
 The University of Kentucky Research
Foundation named it as "Elograph" .
 The "Elograph" was not transparent like
modern touch screens.
 In 1974, the first true touch screen
incorporating a transparent surface came.

5. ❑Block Diagram

6. ❑Components of Touch Screen
A basic Touch screen has three main components:
1.Touch Sensor
2.Controller
3.Software Driver

7. ❑Touch Sensor
 A touch screen sensor is a clear glass
panel with a touch responsive surface
which is placed over a display screen.
 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.

8. ❑Controller
 The 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.

9. ❑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 event information
that is sent from the controller.
 Most touch screen drivers today are mouse-emulation type drivers. This
makes touching the screen the same as clicking your mouse at the same
location on the screen.

10. ❑Typers of Touch Screens
 RESISTIVE
 CAPACITIVE
 SURFACE WAVE
 INFRARED

11. ❑Resistive Touch Screen
 Resistive touchscreens are pressure sensitive, so they can be
operated with any input device, including a gloved hand or
stylus.
 easily damaged by sharp objects.
 they offer only 75% clarity.

13. ❑Capacitive Touch Screen
 Capacitive screens are resistant to outside elements,
making them very durable.
 capacitive panels must be touched with a finger.
 maintains high clarity.

15. ❑Surface Wave Touch Screen
 Surface wave touch screen are more advanced technology
that provides high durability and can be operated by either
human touch or stylus.
 offers highest clarity.
 considerably more expensive.

17. ❑Infrared Wave Touch Screen
 It use an array of infrared (IR) light-emitting diodes (LEDs) on two
adjacent bezel edges of a display, with photosensors placed on the
two opposite bezel edges to analyze the system and determine a
touch event. The LED and photosensor pairs create a grid of light
beams across the display.
 An object (such as a finger or pen) that touches the screen
interrupts the light beams, causing a measured decrease in light at
the corresponding photosensors. The measured photosensor
outputs can be used to locate a touch-point coordinate.

19. ❑Uses of Touch Screen
 Public Information Displays
 Customer Self-Services
 Computer Based Training
 Assistive Technology

20. ❑Advantages
 Ideal for web browsing, picture and movies.
 Simple user interfaces, which are more intuitive (iPhone
once again is a good example).
 Touchscreen devices have fewer buttons .
❑Diadvantages
 Big screen leads to low battery life.
 These devices require massive computing power which
leads to slow devices and low battery life.

21. ❑Future Scope
Holographic touch screens
Wood Touch Tables

22. ❑References
 Sandbach, David Lee: Position detector constructed
from fabric, European patent EP 0989509A2
 Microtouch Systems, Inc.: Frontally Shielded Capacitive
touch sensor system, United States Patent US5457289
 Microtouch Systems, Inc.: Touchscreen controller with pen
andor finger inputs, United States Patent US5457289