The industrial touch screen is applied to industrial monitor, industrial all-in-one panel PC. It can be divided into non-touch, resistive touch, and capacitive touch screen. Capacitive touch is a common touch mode. When the industrial capacitive screen fails, how to solve it? What are the principles to follow? Here let's talk about it.
The transparency and definition of the capacitive touch screen are better than that of the four-wire resistance touch screen, but it can't be compared with the surface acoustic screen and five-wire resistance screen. The reflection of the capacitance screen is serious. Moreover, the light transmittance of the four-layer composite touch screen of the capacitance technology is uneven for each wavelength light, and there is the problem of color distortion. Due to the reflection of the light among the layers, the image and characters are blurred.
In principle, the capacitive screen uses the human body as an electrode of a capacitor element. When there is enough capacitance between the conductor and the ITO working surface of the interlayer, the flowing current is enough to cause a malfunction to the capacitive screen.
Although the capacitance is inversely proportional to the distance between poles, it is directly proportional to the relative area and also related to the insulation coefficient of the medium. Therefore, when a large area of palm or hand-held conductor is close to the capacitive screen while not touching, it can cause the malfunction of the capacitive screen. In wet weather, this phenomenon is particularly obvious. Holding the monitor by hand, palm within 7cm of the monitor or body within 15cm of the monitor can cause the malfunction of the capacitive screen. Another problem of capacitive screens is that they do not react when touching with gloved hands or non-conductive objects in hand, because more insulating media are added.
The main disadvantage of the capacitive touch screen is drift: when the environment temperature and humidity change, and the environment electric field changes, the capacitive screen will drift, resulting in inaccuracy.
Some reasons will cause the drift phenomenon:
1. The temperature rise of the monitor after power-on.
2. When the user touches the screen, the other hand or one side of the body near the monitor.
3. When moving away the large objects near the capacitive touch screen.
4. Someone comes around to watch when the user touches the capacitive screen.
The reason for the drift of the capacitive screen belongs to the congenital shortage of technology, the environmental potential surface (including the user body), although it is far away from the capacitive touch screen, it is much larger than the area of fingers, which directly affects the measurement of the touch position.
The so-called "Drift phenomenon" of capacitive screen mainly refers to the following situations:
1. Making mistake action to touch operation, i.e. when touching point A location, touching response from point B location;
2. Without touching, but shows a mistake action, it refers to the body of conductive material is close to the screen, and has not touched, but it will make a touching response;
3. No response from the screen after touch operation, that is to say, the touch screen has no response after the finger touched the display.