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Shenzhen Geshem Technology Co., Ltd.
Shenzhen Geshem Technology Co., Ltd.

The Working Principle of Industrial Tablet Touch Screen

The industrial tablet computer integrates the host, display and touch screen into one. It has the characteristics of good stability, high reliability and strong scalability. It is widely used in self-service terminals, medical equipment, industrial control, automation equipment, telecommunications, electricity, network, etc. Rail transit and other fields.


At present, the commonly used touch screens in industrial tablet computers include resistive touch screens, capacitive touch screens, infrared touch screens and surface acoustic wave touch screens.


1. Four-wire resistive tablet PC


The four-wire resistance screen is attached with two transparent conductive layers of ITO between the surface protective coating and the base layer, the two layers correspond to the X and Y axes respectively, and the two layers are insulated with fine transparent insulating particles.


When the screen of the industrial tablet computer is touched, the generated pressure causes the two conductive layers to be connected, and the touch industrial tablet computer obtains the X and Y coordinates of the touch point due to the change of the resistance value.


2. Five-wire resistive tablet computer


The base layer of the five-wire resistance screen is attached with a transparent conductive layer ITO that applies the voltage fields in the X and Y directions to the same layer, and the outermost nickel metal conductive layer is only used as a pure conductor.


When touching the screen of the industrial tablet computer, the method of detecting the X-axis and Y-axis voltage values of the inner layer ITO contact point is time-sharing to measure the position of the touch point. The inner layer ITO needs four leads and one outer layer, a total of 5 leads.


3. Capacitive touch panel computer


The capacitive touch screen is composed of a glass protective layer, a conductive layer, a non-conductive glass screen, and a conductive layer from the outside to the inside. The innermost conductive layer is the shielding layer, and the voltage is connected to the four corners or four sides of the middle conductive layer. Tiny direct current is spread on the surface of the screen to form a uniform electric field.


When the screen of the industrial tablet computer is touched by hand, the human body acts as one pole of the coupling capacitor, and the current is collected from the four corners of the industrial tablet computer to form the other pole of the coupling capacitor. The controller calculates the relative distance from the current to the touch position to obtain the coordinates of the touch.


4. Infrared touch tablet PC


The infrared touch screen uses a densely distributed infrared matrix in the X and Y directions to detect and locate the user's touch.


The infrared touch screen is equipped with a circuit board frame in front of the display, and the circuit board is arranged with infrared transmitting tubes and infrared receiving tubes on the four sides of the tablet computer screen, forming a horizontal and vertical cross-infrared matrix in one-to-one correspondence.


When touching the screen of the industrial tablet computer, the finger will block the horizontal and vertical infrared rays passing through the position, so the position of the touch point on the screen can be determined. Any touch object can change the infrared rays on the touch point to realize the touch screen operation.


5. Surface acoustic wave touch tablet PC


Surface acoustic wave is a kind of ultrasonic wave. The mechanical energy wave propagating on the surface of the medium (such as rigid materials such as glass or metal) can be directional and small angle through the wedge-shaped triangular base (strictly designed according to the wavelength of the surface wave). Surface acoustic wave energy emission.


The three corners of the surface acoustic wave touch screen are respectively pasted with transducers for transmitting and receiving acoustic waves in the X and Y directions (made of special ceramic materials, divided into transmitting transducers and receiving transducers; it is the controller The electrical signal sent through the touch screen cable is converted into acoustic wave energy and the surface acoustic wave energy gathered by the reflection stripes is converted into an electric signal), and the four sides are engraved with reflection stripes reflecting the ultrasonic waves on the surface.


When a finger or a soft object touches the screen of an industrial tablet computer, part of the sound wave energy is absorbed, so the received signal is changed, and the X and Y coordinates of the touch are obtained through the processing of the controller.

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