What is the principle of mobile phone touch screen? Why do you know where we ordered?

The screen body of the resistive touch screen is a multi-layer composite film with a layer of glass or plexiglass as the base layer. The surface is coated with a transparent conductive layer and covered with a hardened, smooth and scratch-resistant plastic layer. . Its inner surface is also coated with a conductive layer, and there are many small transparent isolation points between the two conductive layers to separate them.

When a finger touches the screen, the two conductive layers that are normally insulated from each other make a contact at the touch point. Because one conductive layer is connected to a 5V uniform voltage field in the Y axis direction, the voltage of the detection layer changes from zero to zero. If it is non-zero, the controller detects this connection, performs analog-to-digital conversion, and compares the voltage value obtained with 5V to obtain the Y-axis coordinate of the touch point, and the X-axis coordinate can be obtained in the same way.

The capacitive touch screen does not rely on finger pressure to change the voltage value to detect coordinates. Capacitive screens work through any object that holds electrical charge, including human skin. (Charge carried by the human body) Capacitive touch screens are made of materials such as alloys or indium tin oxide (ITO), and the charges are stored in tiny electrostatic nets that are thinner than hair. When a finger taps on the screen, a small amount of current will be absorbed from the contact point, causing a voltage drop in the corner electrode. The touch is achieved by sensing the weak current of the human body.