The theory of resistive touch panel works

2022-04-29 13:56:21 145

The working principle,including 4 wire resistive touch screen and 5 wire resistive touch screen is mainly to realize the operation and control of the screen content through the principle of pressure sensing. The screen body part of this touch screen is a multi-layer composite film that is very compatible with the display surface. The first layer is glass or plexiglass. The bottom layer, the second layer is the partition layer, the third layer is the multi-component resin surface layer, and the surface is also coated with a transparent conductive layer, which is covered with a hardened, smooth and scratch-resistant plastic layer on the outer surface. The conductive layer and glass layer sensor on the surface of the polyester surface layer are separated by many tiny spacers. The current passes through the surface layer. When the surface layer is touched lightly, it touches the bottom layer, and the controller reads the corresponding current and Calculate the distance of the finger position. This touch screen uses two highly transparent conductive layers to form a touch screen, and the distance between the two layers is only 2.5 microns. When the finger touches the screen, the two conductive layers that are usually insulated from each other have a contact at the touch point. Because one of the conductive layers is connected to the 5V uniform voltage field in the Y-axis direction, the voltage of the detection layer changes from zero to If it is not zero, after the controller detects this connection, it performs A/D conversion, and compares the obtained voltage value with 5V to obtain the Y-axis coordinate of the touch point, and similarly obtains the X-axis coordinate. It is the most basic principle common to all resistive technology touch screens. [3]