XIANHENG TECH
China LCD module manufacturer
By shenzhen touchscreen supplier | 10 April 2019 | 0 Comments

The 4 Types Of Touch Screen

According to the working principle of information transmission and touch screen media, we put the touch screen is divided into four types, they were resistive, inductive and capacitive infrared type, surface acoustic wave, following a brief introduction to the various types of touch screen:
 

1. resistive touch screen

The resistive touch screen body part of the screen is a multilayer film and liquid crystal screen surface is very complex, which consists of a layer of glass or organic glass is used as the base, the surface coated with a layer of transparent conductive layer (OTI, indium oxide). When a finger touches the screen, the two conductive layer OTI a contact point, because the direction of one side of the conductive layer on the Y axis of the 5V uniform field voltage, the voltage detection layer changes from zero to zero, the switch on the controller to detect, A/D conversion, and then the voltage value compared with 5V. You can touch the Y axis point, in that position on the X axis, which is the most basic principle of resistive touch screen in common. Resistance screen according to the number of out of line, divided into four lines, five wire and other wire resistance touch screen. The A surface of the five wire resistance touch screen is a conductive glass instead of a conductive coating layer, and the process of the conductive glass greatly improves the service life of the conductive glass, and the transmittance can be improved.

2. capacitive touch screen

The structure of the capacitive touch screen is mainly that a transparent film layer is plated on the glass screen, and a protective glass is additionally arranged on the conductor layer.

Capacitive touch screen is a transparent glass on the surface of a special metal conductive material. When the finger is touched on the metal layer, the capacitance of the contact changes, so that the frequency of the oscillator connected is changed. Because of the variation of capacitance with temperature, humidity or grounding, the stability is poor, and the drift phenomenon often occurs. This kind of touch screen is suitable for the debugging phase of system development.

3. infrared touch screen

Infrared touch screen is free from current, voltage and electrostatic interference, suitable for some harsh environmental conditions. The utility model has the advantages of low cost, convenient installation, no need of cards or any other controller, and can be used on various grades of computers. In addition, because there is no capacitor charging and discharging process, the response speed is faster than the capacitance type, but the resolution is low.

The principle of infrared touch screen is very simple, only on the display with the distance from the frame, no need to add a coating on the surface of the screen or feeder controller.  The utility model has the advantages of low cost, convenient installation, no need of cards or any other controller, and can be used on various grades of computers. However, due to the addition of the frame in the ordinary screen, in the use of the frame around the infrared emission tube and receiving tube is easy to damage.

4. surface acoustic wave touch screen

Surface acoustic wave is a mechanical wave propagating along the surface of the medium. The touch screen is composed of touch screen, acoustic generator, reflector and acoustic receiver, wherein the acoustic generator can send a high-frequency sound waves across the surface of the screen when the finger touch screen, the acoustic contact is prevented, thereby determine the coordinate position. The touch screen part of the surface acoustic wave touch screen can be a flat surface, a spherical surface or a cylindrical glass plate, which is arranged in front of the CRT, LED, LCD or the plasma display screen. This glass plate is only a pure reinforced glass, unlike other touch screen technology is not any film and coating. The upper left corner and the lower right corner of the glass screen are respectively provided with a vertical and horizontal ultrasonic transmitting transducer, and two corresponding ultrasonic receiving transducers are fixed at the upper right corner. The four sides of the glass screen are engraved with a very precise reflection fringe of the 45 degree angle from sparse to dense.

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