Capacitive touch screen structure is mainly in the glass screen with a layer of transparent film layer, and then in the conductor layer plus a protective glass, double glass design can completely protect the conductor layer and the sensor. Capacitive touch screen in the touch screen are coated with long and narrow sides of the electrode, in the conductor to form a low voltage AC electric field. In touching the screen, due to the human body electric field, between the fingers and the conductor layer will form a coupling capacitor, the four sides of the electrode current will flow to the contact, and the current strength and the finger to the electrode is proportional to the distance, after the touch screen controller Will calculate the proportion of current and strength, accurately calculate the location of the touch point. Capacitive touch screen double glass not only protects the conductor and the sensor, more effectively prevent the external environment factors affect the touch screen, Capacitive Touch Screen even if the screen stained with dirt, dust or grease, capacitive touch screen can still accurately calculate the touch position.
As the capacitance with the contact area, the dielectric of the different changes, so the stability is poor, often produce drift phenomenon. This kind of touch screen is suitable for the debugging phase of system development.
Capacitive touch screen principle
Is the use of the body's current sensing work. Capacitive touch screen is a four-layer composite glass screen, the inner surface of the glass screen and the interlayer are coated with a layer of ITO, the outermost layer is a thin layer of siliceous glass protective layer, Capacitive Touch Screen sandwich ITO coating as a face, Capacitive Touch Screen four corners Four electrodes, the inner ITO for the shield to ensure a good working environment.
When the fingers touch on the metal layer, due to the human body electric field, the user and the touch screen surface to form a coupling capacitor, for high frequency current, the capacitor is a direct conductor, so the fingers from the contact point suction a small current. Capacitive Touch Screen This current flows out of the electrodes on the four corners of the touch screen and the current flowing through the four electrodes is proportional to the distance from the finger to the four corners. The controller calculates the position of the touch point by accurately calculating the four current ratios The
Capacitive touch screen advantages are:
1. Operation novelty. Capacitive touch screen support multi-touch, more intuitive operation, more fun.
It is not easy to touch. As the capacitive touch screen needs to be sensed to the body of the current, only the human body to its operation, with other objects will not touch the corresponding, so the basic to avoid the possibility of false touch.
3. High durability. Compared with the resistive touch screen, capacitive touch screen in the dust, water, wear and other aspects of a better performance.
As the current legitimate red touch screen technology, capacitive touch screen, Capacitive Touch Screen although the interface with gorgeous, multi-touch, only the human body and other advantages