07-04-2011, 02:30 PM
Presented By
Sumi Scaria
[attachment=11854]
INTRODUCTION
Most sophisticated computer access technology.
Detect the presence and location of a touch.
Eliminates the need for the mouse and keyboard.
The touchscreen has two main attributes:
Enables to interact with what is displayed on screen.
No intermediate devices required.
HISTORY
Emerged in the second half of the 1960s.
In 1971, Sam Hurst, invented first touch sensor
In 1977 , "touchscreen."
TECHNOLOGIES
1) RESISTIVE:
Composed of two thin, metallic, conductive layers.
Change in current is registered as touch event.
Advantages:
fingertip input.
Costs low.
Supports multi-touch input.
Not affected by outside elements.
DISAdvantages:
Offer only 75% clarity.
The layer can be damaged.
Cannot press hand down on the screen while writing.
2) SURFACE ACOUSTIC WAVE:
Uses ultrasonic waves.
It is based on sending waves across a clear glass panel with a series of transducers and reflectors.
Advantages:
High touch resolution.
Highest image clarity.
Glass panel.
Disadvantages:
Touched by finger, gloved
hand, or soft-tip stylus.
Not completely sealable.
3) CAPACITIVE:
Consists of insulator coated with a transparent conductor.
Touching results in a distortion of the electrostatic field.
Advantages:
Not affected by outside elements.
high clarity.
Multi touch support available.
High touch resolution.
Disadvantages:
Must be touched by finger.
More expensive.
Surface capacitance:
Only one side of the insulator is coated with a conductive layer.
A small voltage is applied to the layer.
Projected capacitance:
Permits more accurate and flexible operation, by etching the conductive layer.
4) INFRARED:
It employs one of two very different methodologies.
Use an array of infrared light-emitting diodes.
Advantages:
Military applications.
Have the most durable surfaces.
Disadvantages:
Relatively high cost.
Issue of performance in bright ambient light.
5) Strain gauge :
The screen is spring-mounted on the four corners.
Used to determine deflection when the screen is touched.
6) Optical imaging:
Two or more image sensors are placed around the edges of the screen.
Revolutionizes the way we interface with computer technology.
7) Dispersive signal technology:
Chemically-strenghtened glass substrate with piezos mounted on each corner.
Determines position by pinpointing the source of “bending waves”.
Disadvantages:
After the initial touch the system cannot detect a motionless finger.
8) Acoustic pulse recognition:
Uses four piezoelectric transducers located at each side of the screen.
Turn the mechanical energy of a touch into an electronic signal.
Advantages:
Optics and durability of pure glass.
Works with finger, glove, pen.
Resistant to water, dust, grease.
DISADVANTAGES:
After the initial touch the system cannot detect a motionless finger.
Comparison of touchscreen technologies
CONSTRUCTION
Three main components:
1) Touch Sensor
Touch response surface.
It is a clear glass panel.
2) Controller
Interface between a touch screen sensor and the device the sensor is used to control.
determines what type of interface/connection.
3) Software Driver
Software update for the PC system.
Allows the touchscreen and computer to work together.
WORKING
control board.
Electrically conducting layer.
print circuit board.
APPLICATIONS
Public Information Displays.
Retail and Restaurant Systems .
Customer Self-Service.
Control and Automation Systems.
Computer Based Training.
Assistive Technology.
Sumi Scaria
[attachment=11854]
INTRODUCTION
Most sophisticated computer access technology.
Detect the presence and location of a touch.
Eliminates the need for the mouse and keyboard.
The touchscreen has two main attributes:
Enables to interact with what is displayed on screen.
No intermediate devices required.
HISTORY
Emerged in the second half of the 1960s.
In 1971, Sam Hurst, invented first touch sensor
In 1977 , "touchscreen."
TECHNOLOGIES
1) RESISTIVE:
Composed of two thin, metallic, conductive layers.
Change in current is registered as touch event.
Advantages:
fingertip input.
Costs low.
Supports multi-touch input.
Not affected by outside elements.
DISAdvantages:
Offer only 75% clarity.
The layer can be damaged.
Cannot press hand down on the screen while writing.
2) SURFACE ACOUSTIC WAVE:
Uses ultrasonic waves.
It is based on sending waves across a clear glass panel with a series of transducers and reflectors.
Advantages:
High touch resolution.
Highest image clarity.
Glass panel.
Disadvantages:
Touched by finger, gloved
hand, or soft-tip stylus.
Not completely sealable.
3) CAPACITIVE:
Consists of insulator coated with a transparent conductor.
Touching results in a distortion of the electrostatic field.
Advantages:
Not affected by outside elements.
high clarity.
Multi touch support available.
High touch resolution.
Disadvantages:
Must be touched by finger.
More expensive.
Surface capacitance:
Only one side of the insulator is coated with a conductive layer.
A small voltage is applied to the layer.
Projected capacitance:
Permits more accurate and flexible operation, by etching the conductive layer.
4) INFRARED:
It employs one of two very different methodologies.
Use an array of infrared light-emitting diodes.
Advantages:
Military applications.
Have the most durable surfaces.
Disadvantages:
Relatively high cost.
Issue of performance in bright ambient light.
5) Strain gauge :
The screen is spring-mounted on the four corners.
Used to determine deflection when the screen is touched.
6) Optical imaging:
Two or more image sensors are placed around the edges of the screen.
Revolutionizes the way we interface with computer technology.
7) Dispersive signal technology:
Chemically-strenghtened glass substrate with piezos mounted on each corner.
Determines position by pinpointing the source of “bending waves”.
Disadvantages:
After the initial touch the system cannot detect a motionless finger.
8) Acoustic pulse recognition:
Uses four piezoelectric transducers located at each side of the screen.
Turn the mechanical energy of a touch into an electronic signal.
Advantages:
Optics and durability of pure glass.
Works with finger, glove, pen.
Resistant to water, dust, grease.
DISADVANTAGES:
After the initial touch the system cannot detect a motionless finger.
Comparison of touchscreen technologies
CONSTRUCTION
Three main components:
1) Touch Sensor
Touch response surface.
It is a clear glass panel.
2) Controller
Interface between a touch screen sensor and the device the sensor is used to control.
determines what type of interface/connection.
3) Software Driver
Software update for the PC system.
Allows the touchscreen and computer to work together.
WORKING
control board.
Electrically conducting layer.
print circuit board.
APPLICATIONS
Public Information Displays.
Retail and Restaurant Systems .
Customer Self-Service.
Control and Automation Systems.
Computer Based Training.
Assistive Technology.
