2. INTRODUCTION
Most sophisticated computer access technology.
Detect the presence and location of a touch.
Eliminates the need for the mouse and keyboard.
3. HISTORY
Emerged in the second half of the 1960s.
In 1971, Sam Hurst, invented first touch sensor
In 1977 , "touchscreen."
4. 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.
7. DISADVANTAGES
Offer only 75% clarity.
The layer can be damaged.
Cannot press hand down on the screen while writing.
8. 3) CAPACITIVE:
Consists of insulator coated with a transparent
conductor.
Touching results in a distortion of the electrostatic field.
9. 4) INFRARED:
It employs one of two very different methodologies.
Use an array of infrared light-emitting diodes.
10. 5) Strain gauge :
The screen is spring-mounted on the four corners.
Used to determine deflection when the screen is
touched.
11. 6) Optical imaging:
Two or more image sensors are placed around the edges of
the screen.
Revolutionizes the way we interface with computer
technology.
12. 7) Dispersive signal technology:
Chemically-strengthened glass substrate with piezos
mounted on each corner.
Determines position by pinpointing the source of
“bending waves”.
13. 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
15. 2) Controller
Interface between a touch screen sensor and the device
the sensor is used to control.
Determines what type of interface/connection.
17. APPLICATIONS
Public Information Displays.
Retail and Restaurant Systems .
Customer Self-Service.
Control and Automation Systems.
Computer Based Training.
Assistive Technology.
