1. TOUCH SCREEN TECHNOLOGY

2. DEFINITION
 What is touch screen

3. INTRODUCTION
 Works with the principle of CRT (Cathode Ray
Tube) technology.
 Input device --> Operates a PC by simply touching
the display screen.
 Made of sensitive glass overlay & desired inputs
can be given by touching it.
 Inputs --> External (light pen) or an internal device
(touch overlay and controller) .

4. COMPONENTS OF TOUCH SCREEN
 Three major components viz,
 Touch sensor
 Controller
 Software driver

5. TOUCH SENSORS
Touch
sensor
Covering screen

6. CONTD..
 Touch sensor --> In between clear glass panels.
 Responsive area --> Entire viewable area of the display
screen.
 Sensors --> Detects electrical current or signal.
 Touching -->causes a voltage or signal change, thereby
the location can be determined.

7. CONTROLLER

8. CONTD…
 PC card --> Touch sensor and the PC.
 Change in voltage --> Translated into the information
that CPU understands.
 Translated bits --> Position where the touch occurs.
 Processor --> change the screen accordingly.

9. SOFTWARE DRIVER
 Acts as a bridge --> Screen and processor.
 Makes the operating system --> To interpret the
touch event information.
 Touch screen drivers today --> Mouse-emulation
type driver ( like touching the screen the same as
clicking mouse)
 Recent research --> To make it as PNP

10. TYPES OF TOUCH SCREEN
 Resistive Touch screen
 Surface wave Touch screen
 Capacitive Touch screen
 Surface capacitive
 Projected capacitive
 Infrared Touch screen

11. RESISTIVE TOUCH
SCREENS

12. RESISTIVE TOUCH SCREEN

13. CONTD…
 1. Polyester Film.
 2. Top Resistive Layer.
 3. Conductive Transparent Metal Coating.
 4. Bottom Resistive Layer .
 5. Insulating Dots .
 6. Glass Substrate

14. WORKING OF RESISTIVE
SENSORS
 Resistive touch screen monitor composed of :
 Flexible top layer
 Rigid bottom layer
 Insulating dots
 Along with touch screen controller.
 Top & Bottom layers --> transparent metal oxide coating.
 Pressure over the flexible top sheet --> Makes electrical
contact between the resistive layers & the switch closing in
the circuit.
 Controller --> Alternating voltages & converts them into the
digital X and Y coordinates.

15. CONTROLLER
 NAME:
 VS20UA
CONTROLLER
 Supply Voltage
 5.0V DC
 Maximum Current
 20mA
 Resolution
 12-bit

16. PROPERTIES
2 conductive layers that connects when touched.
 Capable of multi touch.
 Not affected by dirt or dust.
 Good for outdoor use.

17. SURFACE WAVE TOUCH
SCREEN
Introduction

18. SURFACE WAVE TOUCH SCREEN

19. WORKING OF SURFACE WAVE
SENSORS
 Contains Transmitting and receiving transducers
 Touch screen controller --> 5 MHz electrical signal to the
transmitting transducer.
 Converts electrical signal --> ultrasonic waves within the
glass.
 Waves --> Directed across the front surface of screen.
 Reflectors - -> Reflects & directs towards receiving
transducer.
 Receiving transducer --> reconverts --> An electrical signal &
digitally maps the touch screen

20. CONTROLLER
 NAME:
 2701RSU CONTROLLER
 Voltage
 +5 VDC
 Baud Rate
 9600
 Touch Resolution
 12bit, size independent
 Conversion Time
 10 ms per coordinate set

21. CAPACITIVE TOUCHSCREEN
Introduction

22. CAPACITIVE TOUCHSCREEN
 Figure

23. WORKING OF CAPACITIVE
TOUCHSCREEN
 Uniform conductive coating on a glass panel.
 Operation --> Electrodes around the panel's edge
evenly distribute a low voltage across the
conductive layer & creates an uniform electric field.
 Finger touch --> Draws current from each corner.
 Controller --> Measures ratio of the current flow
from the corners & calculates the touch location.
 Capacitance --> Finger and the sensor grid.

24. LAYERS OF CAPACITIVE
TOUCHSCREEN
 Contains 3layers ,viz
 Front Protective glass
 Back protective glass
- provides optical & strength enhancement options
 Middle layer
 laminated sensor grid
micro-fine wires

25. CONTROLLER
 Name:
 5000 RSU SERIAL
CONTROLLER
 Supply Voltage:
 +5 V DC or +12V
 Baud Rate
 9600 (default) and 19200
 Touch Resolution
 12bit, size independent.
 Conversion Time
 Approximately 15 ms per
coordinate set

26. PROPERTIES
 Conductive coating that emits electric field.
 Very durable.
 Must be touched by some conductive materials.
 Capable of multi touch.

27. PROS & CONS OF TOUCH
SCREENS
PROS CONS
 Direct pointing to the  Low precision when we use
objects. finger.
 Fast.
 Screen may be covered
 Finger or pen is usable (No more by using hand
cable required)
 No direct activation to the
 No keyboard necessary selected function
 Suited to all interactive
applications.

28. APPLICATIONS
 Public Information Displays:::
 Tourism displays
 Trade show display
 Awareness kiosks
 Customer Self-Services:::
 General departmental Stores
 Restaurants
 ATMs
 Airline ticket terminals, etc.
 Other uses:::
 Digital jukeboxes
 Computerized gaming
 Student Registration systems, etc.

29. EXCLUSIVE HIGH PERFORMANCE
OF TOUCH SCREEN TECHNOLOGY
 High resolution enhanced infrared
BENEFITS
1:Easier to pin point
2:Better drag and drop
3:Extra resolution
4:Better sensitivity to environment

30. RECENT PRODUCT S
UNDER DEVELOPEMENT

31. RECENT TRENDS
 Introduction of
 i-PAN7: Flat
Touchscreen computer -
Panel PC
 Introduced by Keith &
Koep of Japan.
 Small frame computer.
 Runs with Windows
Embedded CE & built with
low power ARM
processor.
 Uses Capacitive touch
panels.

32. DISADVANTAGES
 User hand’s may obscure the screen
 Screens need to be installed at lower position
and tilted to reduce arm fatigue
 Some reduction in image brightness may occur
 They cost more than alternative devices

33. HOW IS TOUCH SCREEN DIFFERENT
FROM OTHER DEVICES
 No special commands to learn
 No use of keyboards
 Entering wrong information is impossible
 No fear of damage or lost of loose hardware
pieces

34. CONCLUSION
 Though the Touch screen technology contains
some limitations it’s
 user friendly.
 Fast.
 Accurate.
 easy to operate.
 It has been widely accepted and a little modification
can replace the mouse and key board completely in
near future.