Touch screen technology has the potential to replace most functions of the mouse and keyboard. In the realm of kiosk solutions, the customer is able to use kiosk units without mice and keyboards.
Nowadays there are three types of touch screen technologies applied in our products:
- Resistive
- Surface acoustic wave (SAW)
- Infrared
The resistive technology is applied on two layers with overlaying a hard-coated ITO on a conductive clear glass. These two layers are held apart by spacers (dot). When the flexible layer is touched and contacts the other layer that is set on the stable glass, the voltage is detected and measured from same voltage applied as an electrical field. The controller uses voltage measured from along the X-Y axis to calculate the position of the touch. The advantage of resistive technology is referred to the cheap price, but the surface of resistive panel is not solid as capacitive panel, it cannot sustain strong punches and work in harsh environment.
The surface acoustic wave (SAW) technology is based on two transducers (transmitting and receiving) placed for the both of X and Y axis on the touch panel. The other important element of SAW is placed on the glass, called reflector. The controller sends electrical signal to the transmitting transducer, and transducer converts the signal into ultrasonic waves and emits to reflectors that are lined up along the edge of the panel. After reflectors refract waves to the receiving transducers, the receiving transducer converts the waves into an electrical signal and sends back to the controller. When the user touches the panel, the user absorbs a portion of the wave travelling across it. The controller compares and calculates the change of signal that transducers emits and receives. The calculation processes for both X and Y axis independently.
The infrared technology is applied on touch panels that place infrared receivers and CRT utilizing infrared Light Emitting Diodes (LED) along the horizontal and vertical X-Y axis. When a user touch the surface of screen, the infrared emitted from LED beam is broken and receiver transmits X-Y axis information to the PC port via touch controller.
|
Resistive |
SAW |
Infrared |
| Contact |
Any medium |
Finger, gloves |
Any medium |
| Method |
Current detection |
Wave detection |
Signal interruption |
| Material |
Glass and polyester |
Glass |
Plastic |
| Transp. |
90% |
98% |
98% |