# Structure and Detection Mechanism of 5wire Resistive Touch Screen

## Structure 5wrie resistive touch screen is a two-layer structure, two materials (film or glass) with ITO are attached with a gap between them so that the ITO layers are facing each other.

Touch input will be made as the top layer is pressed down and the two ITO layers contact.

There are insulators called spacing dots between the top and bottom ITO layers. These spacing dots prevent unintended contacts (inputs) of the ITO layers when not pressed.

## Detection Mechanism

As described above, a touch input would be made when the two transparent conductive layers contact. One of the two conductive layers constructs the X and Y coordinate circuit while the other layer constructs the detection circuit.

As in the below figure, the electrodes A to D are formed on the corners of the bottom layer while the top layer works as detection circuit.

X-coordinate Detection

As indicated in the figure below, the voltage applied between the electrodes A and B is Vcc (5V) while between the electrodes C and D is Ground (0V).

As the touch screen is touched, the top and bottom layer will contact, then the voltage of the X-coordinate circuit at the touched point will be detected at the detection circuit A_in.

Example: If the top and bottom layers contact at the point "A", an X-coordinate voltage of 2.5V will be detected at A_in on the top layer.

Another example: If the top and bottom layers contact at the point "B", an X-coordinate voltage of 4V will be detected at A_in on the top layer.

The detected voltage will be converted into digital data (A/D conversion), then the coordinate point of the X-direction will be detected. Y-coordinate Detection

As indicated in the figure below, the voltage applied between the electrodes B and C is Vcc (5V) while between the electrodes A and D is Ground (0V).

Just like the X-coordinate detection, voltage of the Y-direction will be detected at A_in on the top layer.

Example: If the top and bottom layers contact at the point "A", an Y-coordinate voltage of 2.5V will be detected at A_in on the top layer.

Another example: If the top and bottom layers contact at the point "B", an Y-coordinate voltage of 4V will be detected at A_in on the top layer.

The detected voltage will be converted into digital data (A/D conversion), then the coordinate point of the Y-direction will be detected. 