Capacitive touch screen is mainly composed of glass, touch function sheet (e.g., ITO sensor), FPC and so on. Its working principle is that there are electrode sensors on the corners or edges of the capacitive touch screen, and they form a low-voltage AC electric field on the touch panel by scanning. When no touch occurs, the electric field distribution is uniform. And when the human body or other conductive body (such as fingers) touch the touch panel, will change the electric field distribution, the formation of a coupling capacitance. The presence of this coupling capacitance causes changes in the electric field. The electrode sensor detects these electric field changes and converts them into an electrical signal. The electrical signals are processed by the processing circuitry for amplification, filtering, etc. to remove noise and interference. The processed signals are fed into a microcontroller or similar computing unit, which calculates the coordinate position of the touch through an algorithm. The controller can accurately calculate the position of the touch point through the precise calculation of the current ratio and strength. Specifically, when a finger touches the screen, the electrodes leading from the four corners will flow different proportions of current, which are proportional to the distance from the finger to the electrodes. By measuring the proportion and strength of these currents, the controller can determine the exact position of the touch point.
So, is it feasible to add a layer of glass on top of the capacitive touch screen?
Theoretically, the wider the channel of the capacitive touch screen, the thicker the cover glass can be supported, but the problem also comes that a larger contact area is needed to enable the capacitive screen to be operated to. Most manufacturers in the factory before making a balanced setup, if you want to increase the original capacitive touch screen based on plexiglass, you need to carry out relevant experiments to see how thick the glass can support.
Capacitive touch screen above the addition of a layer of glass, whether it will affect its touch function, mainly depends on a few key factors:
Thickness of the glass: higher-end capacitive touch screen chip through debugging, usually can support to the total thickness of 3mm or more glass cover. However, if the additional glass is too thick, it may affect the normal operation of the touch function, it is recommended that generally do not exceed 1mm, some capacitive screen in the additional 1mm thickness of the glass, it can not respond to the finger operation.
Fixing method: The two pieces of glass need to be fully fixed between them using SCA adhesive, and ensure that there is no air layer in the middle. If the lamination is not done properly, it may lead to touch insensitivity or failure.
Quality of glass: The retrofitted glass needs to have good light transmittance and abrasion resistance to ensure that it will not negatively affect the display effect and service life of the capacitive touch screen.
Note:
1. Installation and commissioning: When adding a glass cover to the touch screen, pay attention to the installation and commissioning process to ensure that the fit and sealing between the glass cover and the touch screen are good, and to avoid bubbles, loosening and other problems.
2. Maintenance and maintenance: Although the glass cover can provide a certain protective effect, it also needs regular maintenance and maintenance. For example, regularly clean the dirt and fingerprints on the surface of the glass cover plate to maintain its good light transmission and beauty.