capacitive touch screen
Jan 23, 2019

The types of capacitive touch screens are divided into surface capacitive touch screens and projected capacitive touch screens.

The surface capacitive touch screen has a simple working principle, low price, and simple designed circuit, but it is difficult to realize multi-touch.The projected capacitive touch screen has the function of multi-finger touch. Both capacitive touch screens have the advantages of high light transmittance, fast response speed, long life, etc. The disadvantage is that as the temperature and humidity change, the capacitance value will change, resulting in poor working stability and frequent drift. Need to proofread the screen frequentlytouch screen_副本
TOUCHSCREENThe basic structure of the capacitive touch screen: the substrate is a single layer of plexiglass, and a transparent conductive film is uniformly forged on the inner and outer surfaces of the plexiglass, and an elongated electrode is plated on each of the four corners of the transparent conductive film of the outer surface.The working principle is: when the finger touches the capacitive touch screen, the high frequency signal is turned on at the working surface, and the finger forms a coupling capacitance with the working surface of the touch screen, which is equivalent to the conductor, because the working surface has a high frequency signal, and when the finger touches A small current is drawn at the touch point. This small current flows out from the electrodes at the four corners of the touch screen. The current flowing through the four electrodes is proportional to the linear distance from the finger to the four corners. The controller calculates the contact point coordinate value by calculating the ratio of the four currents.

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