The Classification of Touch Screens and Their Advantages and Disadvantages

According to the working principle of the touch screen and the medium of information transmission, we divide the touch screen into four types, which are resistive, capacitive, infrared, and surface acoustic wave. Each type of touch screen has its own advantages and disadvantages. To understand which type of touch screen is suitable for that occasion, the key is to understand the working principle and characteristics of each type of touch screen technology. Here is a brief introduction to the various types of touch screens mentioned above:

1. Resistive touch screen

The main part of the resistance touch screen is a resistive film screen that fits well with the surface of the display. This is a multi-layer composite film. It uses a glass or hard plastic plate as the base layer, and the surface is coated with a transparent oxide metal conductive layer. It is covered with a layer of hardened outer surface, smooth and anti-scratch plastic layer, and its inner surface is also coated with a layer of coating. There are many small (less than 1/1000 inch) transparent isolation points between them to make the two layers conductive. The layers are separated by insulation.

The working principle of the resistive screen: When the finger touches the screen, the two conductive layers are in contact at the touch point, the resistance changes, and signals are generated in the X and Y directions, and then sent to the resistive touch screen controller. The controller detects this contact and calculates the position of (X, Y), and then operates according to the way of simulating a mouse.

2. Capacitive touch screen

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. The outermost layer is a thin layer of silica glass protective layer. The interlayer ITO coating is used as the working surface, and the four corners lead out four electrodes, the inner layer of ITO is a shielding layer to ensure a good working environment.

3. Infrared touch screen

Infrared touch screen is not interfered by current, voltage and static electricity, and adapts to harsh environmental conditions. Infrared technology is the final development trend of touch screen products.

4. Surface acoustic wave touch screen

Surface acoustic wave, a type of ultrasonic wave, is a mechanical energy wave that propagates shallowly on the surface of a medium (such as glass or metal and other rigid materials). The upper left corner and the lower right corner of the glass screen are respectively fixed with vertical and horizontal ultrasonic transmitting transducers, and the upper right corner is fixed with two corresponding ultrasonic receiving transducers. The four peripheries of the glass screen are engraved with very precise reflection stripes with 45° angles ranging from sparse to dense.