The interior of the capacitive LCD screen is composed of driving electrodes and receiving electrodes. The driving electrode sends out a low-voltage high-frequency signal, which is projected to the receiving electrode to form a stable current. When the human body touches the capacitive screen, since the human body is grounded, the finger and the capacitive screen form an equivalent capacitance.
High-frequency signals can flow into the ground through this equivalent capacitance, so the amount of charge received by the receiving end is reduced. The charge drop is more pronounced when the finger is close to the transmitter. Finally, the contact point is determined according to the current strength received by the receiving end. As for multi-touch, simply speaking, it is screen segmentation. Each group of mutual capacitance modules in each area works independently, and the capacitive screen can independently detect the touch situation of each area, and realize multi-touch after processing.
The touch screen ctp (capacitive LCD) uses the human body current sensor. The capacitive screen is a four-layer composite glass screen. The inner surface and middle layer of the glass screen are coated with ito (nano indium tin oxide). The outer layer is a 0.0015 mm thick seasonable glass protective layer, the middle layer is coated with ito working surface, four electrodes are formed at the four corners, and the inner layer is a shielding layer to ensure the working environment.
When the user touches the capacitive screen, due to the action of the electric field, a coupling capacitance is formed between the user's finger and the work surface. Because there are high-frequency signals on the working surface, the finger will absorb a very small current and flow out from the electrodes at the four corners of the screen. The current flowing through the four electrodes is theoretically proportional to the distance from the finger to the four corners. The response speed is less than 3 milliseconds, and the accuracy rate can reach 99%.
Capacitive LCD Screen & Resistive LCD Screen and Maintenance Methods:
1. If you are using a capacitive LCD screen, it is recommended that you install the correct driver for the capacitive LCD screen when you use it for the first time. The driver must meet the specification requirements for the first time, and then tap the screen with your finger. Using "/" Microtools Touch Software, start "/" to run the screen calibration procedure. After the calibration is complete, the system will automatically calibrate the data stored in the register controller and restart the system instead of following the screen to recalibrate.
2. When using a resistive LCD screen, if you find that the cursor does not move or can only move in a local area, you can check whether the touch area of the LCD screen is pressed by other touch objects. For example, once the LCD screen is pressed by the display casing or the cabinet casing, it means that a certain point has been touched, so the coordinate position fed back to the controller is not accurate, and the cursor cannot be positioned correctly. The distance between the cabinet and the display can be increased if the cabinet shell presses against the touch area. If the display case is pressing against the touch area, try loosening the display case screws slightly
