Capacitive touch screen is the use of the body above the current sensor to implement the touch, the glass inside the screen and the mezzanine has a layer of ito, ito is the face, the protective layer is a thin layer of tidal soil glass, ito four corners above four An electrode, which has ito as a shield, to ensure that the capacitive touch screen has a good working environment. Capacitive Touch Screen We touch the screen with our fingers, in fact, touched the metal layer, according to the role of the human body, our fingers and touch the screen surface to form a coupling capacitor, the capacitor is the conductor, so our fingers suck a small part of the current The Capacitive touch screen can be based on the four electrodes in our absorption of the current draw the touch point of the location. The same time as
Capacitive touch screen has two types, one is the capacitive touch screen, one is self-capacitive touch screen. Among them, the mutual capacitive touch screen is more common, Capacitive Touch Screen mainly by the internal drive electrode and accept the electrode interaction to work, the drive electrode can send low-voltage high-frequency signal, after the projection on the receiving electrode and then form a stable current. When our fingers touch the screen, our fingers and the screen will constitute a capacitor, but the high frequency of the signal through the capacitor into the ground. So that the receiving side of the charge will be reduced, our fingers closer to the signal transmission port, Capacitive Touch Screen the amount of charge will be smaller and smaller, and finally with the strength of the current to determine the location of our touch. The same time as
Capacitive touch screen in order to multi-position touch, the use of the capacitor is to increase the mutual capacitance of this means, with the popular words, that is, the screen block, which each area inside the interactive capacitor is independent The work of non-interference, so multi-point capacitive touch screen can independently monitor the current situation in each region, after the respectively, you can simply on the screen for multi-touch.
Capacitive touch screen can be roughly divided into four layers are: non-conductive glass screen, two conductive layer, glass protective layer. The two conductive layers are in the second and fourth layers, respectively. The innermost conductive layer is a shield, Capacitive Touch Screen can play a shield inside the electrical signal function, the second layer of the conductive layer is the most critical layer, is the core of the entire touch screen, four edges have lead, can detect The location of the touch point.
In the design of touch-screen products, the need for performance and cost trade-offs. Resistive touch screen cost is low, the competition is very intense, but also in performance and applications have some limitations, Capacitive Touch Screen compared with the resistive touch screen, capacitive touch screen has the following advantages:
(1) capacitive touch screen only need to touch, without the need to generate a signal pressure.
(2) capacitive touch screen in the production only once or no need to correct, and resistive type requires regular correction.
(3) capacitive touch screen life will be longer, because the capacitive touch screen components do not need any movement. In the resistive touch screen, the upper ITO film needs to be thin enough to be flexible to bend down to the underlying ITO film.
(4) Capacitance technology is superior to resistance technology in light loss and system power consumption.
(5) capacitive technology wear resistance, long life, Capacitive Touch Screen the user to use the low maintenance costs, so the manufacturer's overall operating costs can be further reduced.
In addition, the choice of capacitance technology or resistance technology depends mainly on the touch screen object. If it is finger touch, capacitive touch screen is a better choice. If you need a stylus, whether plastic or metal, the resistance touch screen can be competent. Capacitive touch screen can also use the stylus, but need a special stylus to match.
Capacitive touch screen has been applied to the iPhone and other handheld devices, positioning a single point track / analog mouse double click is its basic function, and multi-finger gesture operation recognition and application of the current market hot spots. In portable applications, the user in one hand holding the device, can only use the other hand operation, so identify the multi-finger crawling, translation, stretching, compression, rotation, flip and other gesture operation is particularly important.
PSoC capacitive touch screen has been able to achieve multi-point detection, Capacitive Touch Screen which supports two fingers gesture recognition. It is foreseeable that the capacitive touch screen that supports gesture recognition will be shining in the market。