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What Are The Common Faults Of Industrial PCAP Capacitive Touch Screens?

Touch screens including non-touch, resistive touch and industrial pcap capacitive touch and other touch methods. The capacitive touch is a more common touch method. How to solve the problem when the industrial capacitive screen fails? What are the principles to follow?

The Situation Of Industrial PCAP capacitive touch screen Drift:

The so-called "drift" of capacitive screen mainly refers to the following situations:

1) Misoperation of the touch operation, that is, touching point A, but making a touch reaction to point B;

2) There have misoperation without touching, that is, when the body or conductive objects are close to the screen, and there have touch reaction before touching;

3) There is no action on the touch operation, that is, when your finger have touch the touch screen . But the screen does not respond to the touch.

The Working Principle Of Industrial PCAP Capacitive Touch Screen

Before introducing the causes of "drift", it is necessary to introduce the working principle of the capacitive touch screen.

Capacitive touch screens use the current induction of the human body to work. The capacitive touch screen is a four-layer composite glass screen. The inner surface of the glass screen and the interlayer are each coated with a layer of ITO (transparent conductive film). The outer layer is a thin layer of silica glass protective layer, and the interlayer ITO coating is used as the working surface. Four electrodes are drawn on the four corners, and the inner ITO is a shielding layer to ensure a good working environment.

When the finger touches the metal layer. Due to the electric field of the human body, a coupling capacitance is formed between the user and the surface of the touch screen. For high-frequency currents, capacitors are direct conductors. Then the finger draws a small current from the contact point. This current flows from the electrodes on the four corners of the touch screen. And the current flowing through these four electrodes is proportional to the distance from the finger to the four corners. The controller obtains the position of the touch point by accurately calculating the proportions of these four currents.

It is precisely because of this working principle of the capacitive screen that the phenomenon of screen skipping occurs. After understanding the working principle of the capacitive screen. It is easy to know the cause of the "drift" of the capacitive screen.