Industrial touch screens are divided into non-touch, resistive touch and capacitive touch. Capacitive touch is a more common touch method. How to solve the problem when industrial capacitive touch screen fails? What are the principles to follow? Let's take a look at the editor below.
The so-called "drift" of the 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. Misoperation is made without touching, that is, the body or conductive objects are close to the screen, and the touch reaction is made before touching;
3. There is no action on the touch operation, that is, the touch screen has been touched with a finger, but the screen does not respond to the touch.
Before introducing the causes of "drift", it is necessary to introduce the working principle of the capacitive screen.
Capacitive 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 and the interlayer of the glass screen are each coated with a layer of ITO (transparent conductive film). The outermost 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 a finger touches the metal layer, due to the electric field of the human body, a coupling capacitor is formed between the user and the surface of the touch screen. For high-frequency current, the capacitor is a direct conductor, so 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 "drift" exists. After understanding the working principle of the capacitive screen, it is easy to know the cause of the "drift" of the capacitive screen.
The reason for the "drift" phenomenon on the capacitive screen is probably the case. No matter what device it is, the first thing to do is to find out the cause in order to prescribe the right medicine.
