What is the working principle of capacitive touch screen
Release time:
2021-07-14 13:17
Source:
You may be unfamiliar with the capacitive touch screen, but the capacitive touch screen is closely related to our lives. It is mainly used on mobile phones and other electronic devices. Let's take a look at the working principle of capacitive touch screen together.

When we touch the screen with a finger on the surface, a certain amount of electric charge will be transferred to the human body. In order to recover these electric charges, we can charge from the four corners of the screen. The amount of charge in each direction When it is proportional to the distance of the contact point, so that we can infer which direction the contact point is in.
There will also be an ITO coating under the surface capacitor coating, usually a metal electrode that needs to be linearized around the screen to reduce the corner and side effects on the magnetic field. Sometimes there is also an ITO shield under the ITO coating to shield noise. The surface capacitive touch screen should be calibrated at least once before use. The sensitive capacitive touch screen can penetrate a thicker protective layer than the surface capacitive touch screen without correction. Inductive capacitive etching different ITO modules on two layers of ITO coating. It is necessary to consider factors such as the total impedance of each module, the impedance of the connecting line between each module, and the parasitic capacitance generated by the intersection of the two layers of ITO modules. In addition, in order to detect finger contact, the area of the ITO module should be smaller than that of a finger. When a diamond pattern is used, the diagonal length is usually limited to between 4 and 6 mm.
The capacitive touch screen technology uses the current sensing of the human body to work. The projected capacitive panel touch technology projection capacitive touch screen is to etch two mutually perpendicular ITO conductive circuit modules on two layers of ITO conductive glass coatings, which are regarded as It is a slider that continuously changes in the X and Y directions. When the current flows through one wire in the drive line, if there is a signal of capacitance change from the outside, it will cause the change of the capacitance node on the other layer of wire. The change of the detected capacitance value can be measured by the electronic circuit connected to it, and then converted into a digital signal by the A/D controller for the computer to perform arithmetic processing to obtain the (X, Y) axis position, and then achieve the purpose of positioning.
Through the above, I believe that everyone knows the working principle of the capacitive touch screen, and I hope it will be helpful to you. If you are interested in the capacitive touch screen, you can have an in-depth understanding.
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