The capacitive touchscreen is made by coating a layer or multilayer conductive material (such as indium tin oxide ito) on the substrate and then sealing the protective cover to protect the electrodes. When other conductors, such as bare fingers or conductive pens, touch its surface, an electronic circuit is formed where the inductor is embedded in the glass to detect the current position, Capacitive Touch Screen thus completing a touch operation.
Capacitive touch screen is the use of the body's current induction work. Capacitive touch screen is a four-layer composite glass screen, the inner surface and interlayer of the glass screen are coated with Ito, the outermost layer is a thin layer of silicate glass, Capacitive Touch Screen the interlayer Ito coating is used as the working face, four electrodes are drawn on four corners, and the inner layer Ito is the shielding layer to ensure a good working environment. When the finger touches the metal layer, due to the human electric field, the user and touch screen surface formed with a coupling capacitor, for high-frequency current, Capacitive Touch Screen the capacitance is direct conductor, so the finger from the contact point to suck away a very small current. Wuhan Sofford hint, this current is divided from the touch screen on the four corners of the electrode outflow, Capacitive Touch Screen and flow through the four electrodes of the current with the finger to the four corners of the distance is proportional to the controller through the accurate calculation of these four current ratio, to reach the location of the touch point.
Capacitive touch screen structure is mainly in the glass screen coated with a layer of transparent film, and then in the conductor layer with a protective glass, double glass design can completely protect the conductor layer and sensors. Capacitive touch screen can be simply seen as a four-layer composite screen of the screen body: the outermost layer is the glass layer, followed by the conductive layer, the third layer is non-conductive glass screen, the most fourth layer is conductive layer. The inner conductive layer is the shielding layer, which plays the role of shielding the internal electrical signal, Capacitive Touch Screen the middle conductive layer is the key part of the whole touch screen, the four corner or four side has direct lead, which is responsible for detecting the position of the touch control point.
The capacitive touch screen is plated with narrow electrodes on the four sides of the touchscreen, forming a low voltage alternating current in the conductive body. In the touch screen, Capacitive Touch Screen due to the human electric field, the finger and the conductor layer will form a coupling capacitor, the current of the four electrodes will flow to the contact point, and the current strength is proportional to the distance of the finger to the electrode, the controller after the touch screen will calculate the current ratio and strength, Capacitive Touch Screen accurately calculate the position of the touch point. Capacitive touch Screen dual-glass can not only protect the conductor and sensors, more effectively prevent external environmental factors on the touch screen, even if the screen stained with filth, dust or grease, capacitive touch screen can still accurately calculate the touch position.
Because the capacitance varies with the contact area and dielectric, Capacitive Touch Screen the stability of the capacitor is poor, and the drift phenomenon is often produced. This kind of touch screen is suitable for the debugging phase of system development.