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Introduction and principle of touch control panel

2019-6-14 9:22:27

The touch panel is coated with a thin film of tin oxide antimony and protective film on the surface of transparent glass, and it is required to prevent electronic signal interference between the touch panel and liquid crystal screen.The touch panel is…

The touch panel is coated with a thin film of tin oxide antimony and protective film on the surface of transparent glass, and it is required to prevent electronic signal interference between the touch panel and liquid crystal screen.

The touch panel is the direct embodiment of touch technology, which is used to sense contact signals and analyze and identify them.


The structure of touch control panel consists of three parts: sensor, controller and software.

The sensor is the part of touch control panel, which mainly receives the input information after contact.

The function of the controller is to analyze and calculate the position of the contact point and convert the analog signal into digital signal so that the input signal can be accepted by the information equipment.

The software section links the communication protocol between the information processing equipment and the controller so that the information processing equipment can receive and recognize the input signals of the controller for subsequent processing.


According to different induction technologies, touch control panels can be divided into four types: resistive type, capacitive type, optical type and acoustic wave type. The principles and characteristics of various technologies are described below.


The resistive touch control panel mainly consists of two groups of ITO conductive layers, gap objects and electrodes.

Mainly based on ITO glass, a layer of ITO film is superimposed on the top, and the support of reverse current device is distributed in the middle, so that the upper and lower plates will not conduct and form induction due to the close distance, and the silver electrode is printed on the edge to provide voltage.

When in use, the upper and lower electrodes are conducted by pressure, and the position of contact point is calculated by the controller to detect the change of panel voltage for input.

Is the advantage of good waterproof, anti - pollution, price?

Appropriate, but the disadvantage is that the resistance to scraping and fire resistance is poor.


Capacitive touch panel is used to detect the coordinates of capacitance changes caused by electrostatic combination between transparent electrode and human body.

In the principle of induction, voltage is applied to four corners of the screen induction area and a fixed electric field is formed. When the finger touches the screen, the electric field can trigger electric current. By measuring by the controller, the contact position can be calculated according to the different proportions of the current distance from the four corners.

However, capacitive touch panel has to overcome the static noise caused by fingers or other touch media, so it is difficult to design the current and structure.

The position can be calculated by the current ratio when the contact pressure is applied.


The components of capacitive touch control panel consist of coating a conductive layer on the glass substrate, making electrode layer, and finally covering a layer of protective film on the surface, which is the completion of capacitive touch control panel, because it only ACTS as electrode and conduction place on a single piece of glass.

The resistive touch control panel needs to overlap the ITO conductive layer of the upper and lower plates, which affects the light transmittance of the overall touch control panel. Therefore, the light transmittance of the capacitive touch control panel is higher than that of the resistive touch control panel, which can reach more than 90%.

Product water resistance, anti - fouling, scratch resistance, and anti - dust and reaction speed.


The principle of optical touch panel is to use the principle of light source receiving and blocking, fill the panel with light source and receiver and arrange it into a matrix.

The optical touch control panel comprises a glass substrate, an infrared source and an infrared receiver.

The infrared transmitter is arranged on the left and lower side of the glass panel, and infrared receiver is set on the right and upper side. When fingers or objects block the infrared ray, the information received by the receiver can be used to measure the matrix position of the contact point.

Its advantage is that the surface of pure glass does not affect the transmittance of light, product reliability, scratch resistance, fire resistance, and the disadvantage is poor waterproof and antifouling.


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