1. PRESENTATION TOPIC :- Touch screen technology
PRESENTATION TOPIC :-
Touch screen technology

2. Points of Discussion Introduction History Working Process Technologies
Applications
Advantages & Disadvantages
Conclusion
References

3. Introduction:
A touch screen is an electronic visual display that can detect the presence and location of a touch within the display area. Touch screens can sense Finger and other passive objects, such as a stylus. However, if the objects sensed is active, as with a light pen.

4. History:
In 1971 Dr. Sam Hurst, founder of Elographics developed the first touch opaque sensor “Elograph” at the University of Kentucky.
In 1974 He developed the first real touch screen.
In 1977, Elographics developed the five-wire resistive technology then with the backing of Siemens Corporation, developed a curved glass sensor called the Touch screen.
The new transparent technology, AccuTouch, was later developed by the founders of Elographics, Dr. Hurst and Bill Colwell.
Now days, Multipoint touchscreen facilitates the tracking of more than one finger on the screen.

5. How Does a Touchscreen Work?
1. Touch Sensor 2. Controller 3. Software Driver

6. 1. Touchsensor:

7. 2. 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.

8. 3. 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.

9. Technologies:
1. Resistive 2. Infrared 3. Capacitive 4. Surface acoustic wave

10. 1.Resistive: Two layers of conductive material
Touch creates contact between resistive layers completing circuit
Voltage in circuit changes based on position
Controller determines location based on voltages
Any material can trigger sensors

11. 2.Infrared: Uses infrared LEDs and matching photodetectors
Touching screen interrupts LEDs
Cameras detect reflected LED caused by touch
Controller able to calculate coordinates from camera data

12. 3.Capacitive: Glass panel with conductive layer (Indium Tin Oxide)
Small amount of voltage applied to four corners of touch screen
Touch draws minute amount of current creating voltage drop
Coordinates of point of contact calculated by controller

13. 4. Surface acoustic wave:
Surface consists of glass overlay with transmitting and receiving transducers
Electrical signals sent to the transmitting transducers converts to ultrasonic waves
Waves are directed across screen by reflectors then directed to receiving transducers
Received values are compared to stored digital maps to calculate x and y coordinates

14. Applications:
Many games use the touchscreens as a primary controlling device.
The popularity of smart phones, ATMs, and many types of information appliances is driving the demand for touchscreens.
Touchscreens are popular in heavy industry and in other situations, such as museum displays or room automation.
Casino and other gaming systems
Computer access for the physically disabled
Point-of-sale terminals
Restaurant systems
Employee time clocks

15. Advantages: Disadvantages:
Mostly used in manufacturing and medical applications since it can be completely sealed.
Operated using a stylus or a gloved finger.
Mechanically stronger
Clearer
More wear resistant
Disadvantages:
It is very sensitive and can be activated by stray touches.
Low resolution
Parallax problems

16. Conclusion:
Designers are trying to use touch screen to simplify input commands
Today , touch screen has becomes adopted by computers users of all abilities because it is simple, fast and innovative.
In future there is no usage of mouse and keyboards as they will be replaced by touch screen.

17. References: www.engineersgarage.com www.nptel.iitk.ac.in

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