Resistive Touch PanelA resistive touch screen is basically comprised of a layer of ITO Film and a layer of ITO Glass. The two layers are separated by DOT. A 5V electrical current is introduced to the ITO Film and ITO Glass. When a user touches the ITO Film with his finger or stylus, the indentation will result in contact with the ITO Glass at the bottom layer to result in a change of voltage.The signal is converted into a digital one by the A/D controller in order for the PC to compute the coordinates (X and Y axis) of the touch event to achieve positioning.
 Surface capacitor touch panel technology is to use ITO of metal frame edge, by sense electro field change of surface. Due to electro field is almost fill with all screen, when finger touch surface, touch panel will send electro to sense finger position. And this touch panel type does not need precisely ITO to process whole touch, positioning, output procedure.
Projected capacitor touch panel.
Projected capacitor touch panel is use capacitor sensing. By using many etched ITO stips, when finger approaches surface, controller IC will detect the varied of capacitance then to quickly calculate position of finger. Due to this action is only sensing varied of capacitance, so finger can be sensed without actually touch surface.
 Infrared touch panel is to use transmit/receive device. Once finger touch surface, finger will cut off the light between transmit/receive device then could calculate finger position.
Optical touch panelsOptical touch panels operate with infrared backlights and image sensors placed around the edges of the screen. The light beams along the X and Y axes form a matrix arrangement. When an opaque object obstructs the beams, the system is able to define the coordinates of the touch on the X and Y axes.
SAW Touch paneltouch panel with three ultrasonic wave transmitters placed at three corners and a receiver placed in the middle to create an even field of acoustic waves. Since acoustic wave has the unique characteristics of losing energy when in contact with a soft medium, it is utilized to achieve positioning of touch input in the application.
Electromagnetic Digitizeroperates based on electromagnetic sensing; it involves the use of an electromagnetic pen that functions as a signal transmitter while the electromagnetic board acts as a receiver. When the transmitter is brought close to the panel surface, the change in magnetic flux is registered for the system to compute and define the coordinates of the touch event. | 
