3. What are Touch Screen Sensors?
“A Touchscreen is a display which can detect the
location of touches within the display area. This
allows the display to be used as an input device,
removing the keyboard and/or the mouse as the
primary input device for interacting with the
display's content.”
4. Types of Touch Screen Sensors
External add on touch screens
Integrated Touch Screen Monitors
5. External Add On Touch Screen Sensor
Can be added to your home computer
Brings touch screen technology to the common user
8. Working Principles
A controller (2) takes information from the touch
screen (1)
The info is turned into information the computer
can understand
• A software
driver is needed
to allow the touch
screen and
computer to work
together (3)
10. Resistive
Composed of several layer including two metallic
layers separated from each other
When metallic layers are connected (touched) they
act as like 2 voltage dividers
Change in electric current is sent to controller and
the location is determined
12. Surface Acoustic Wave
•Uses Ultrasonic waves across the surface
•When the screen is touched part of the
wave is absorbed
•This allows the controller to determine the
position of the touch
13. Capacitive
Coated with a current
conducting material
Sensor has a precisely controlled field of stored
electrons in horizontal and vertical directions
Humans also exhibit capacititance
A controller detects when there is a disturbance in
the electric field (touch)
The controller then determines the location
14. Surface-capacitive touchscreen
Structure
Surface capacitive technology consists of a
uniform conductive coating on a glass panel.
Electrodes around the panel’s edge evenly
distribute a low voltage across the
conductive layer, creating a uniform electric
field.
15. Projected-capacitive touchscreen
During a touch, capacitance forms between the
finger and the sensor grid.The embedded serial
controller in the touchscreen calculates touch
location coordinates and transmits them to the
computer for processing.
16. Surface-capacitive touchscreen
Working principle
A human body is an electric conductor, so when you touch the
screen with a finger, a slight amount of current is drawn, creating a
voltage.s Theoretically, the amount of current that drifts through
the four electrodes should be proportional to the distance from the
touch point to the four corners. The controller precisely calculates
the proportion of the current passed through the four electrodes
and figures out the X/Y coordinate of a touch point.
17. Infrared
An array of infrared sensors are placed horizontally
and vertically
The sensors send out pulses of light
The sensors detect the interruption of the light
The location is then determined by the controller