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What is a capacitive touch screen?

First, touch the touch screen installed on the front of the display with your finger or other objects, and then the system locates and selects the information input according to the icon or menu position touched by your finger. The touch screen is composed of a touch detection component and a touch screen controller; The touch detection part is installed in front of the display screen to detect the touch position of the user, and receive and send back the touch screen controller; The main function of the touch screen controller is to receive touch information from the touch point detection device, convert it into contact coordinates, and then send it to the CPU. At the same time, it can accept and execute commands sent by the CPU

It works by using the current induction of the human body. The capacitive touch screen is a four layer composite glass screen. The inner surface and interlayer of the glass screen are respectively coated with a layer of ITO. The outer layer is a thin layer of silica glass protection layer. The interlayer ITO coating is used as the working surface. Four electrodes are led out from four corners. The inner layer ITO is used as the shielding layer to ensure a good working environment. When the finger touches the metal layer, due to the human body electric field, the user and the touch screen surface form a coupling capacitor. For high-frequency current, the capacitor is a direct conductor, so the finger absorbs a small current from the contact point. This current flows out from the electrodes on the four corners of the other 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 four current proportions.

infrared touch screen

In the early concept, the infrared touch screen had technical limitations such as low resolution, limited touch mode and easy to be disturbed by the environment, so it once faded out of the market. Since then, the second generation infrared screen has partly solved the problem of anti light interference. The third and fourth generations have also improved their resolution and stability, but they have not made a qualitative leap in key indicators or comprehensive performance. However, those who know about touch screen technology know that infrared touch screen is not interfered by current, voltage and static electricity, and is suitable for harsh environmental conditions. Infrared technology is the development trend of touch screen products. The touch screen using acoustic and other materials technology has its insurmountable barrier, such as the damage and aging of a single sensor, fear of contamination of the touch interface, destructive use, and complicated maintenance. As long as the infrared touch screen truly achieves high stability and high resolution, it will surely replace other technical products and become the mainstream of the touch screen market.

In the past, the resolution of the infrared touch screen was determined by the number of infrared tubes in the frame, so the resolution was low. The main domestic products on the market were 32x32 and 40X32. In addition, it was said that the infrared screen was sensitive to light environmental factors, and would be misjudged or even crashed when the light changed greatly. These are just the weaknesses of the infrared screen promoted by foreign non infrared touch screen domestic agents. The resolution of the latest technology, the fifth generation infrared screen, depends on the number of infrared tubes, scanning frequency and difference algorithm. The resolution has reached 1000X720. As for the instability of the infrared screen under light conditions, the second generation infrared touch screen has better overcome the weakness of light interference.

The fifth generation infrared touch screen is a new generation of intelligent technology products. It realizes 1000 * 720 high resolution, multi-level self adjustment and self recovery hardware adaptability and highly intelligent discrimination and recognition, and can be used arbitrarily in various harsh environments for a long time. And it can customize the expansion functions for users, such as network control, acoustic sensing, human proximity sensing, user software encryption protection, infrared data transmission, etc. Another major disadvantage of the original infrared touch screen publicized by the media is its poor anti riot performance. In fact, the infrared screen can completely choose any anti riot glass that the customer thinks is satisfactory without increasing too much cost and affecting the performance, which other touch screens cannot follow.