High Accuracy Of Capacitive Touch Screen

- Oct 16, 2017-

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, 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, the interlayer Ito coating is used as the working face, Capacitive Touch Screen 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, the capacitance is direct conductor, Capacitive Touch Screen 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, 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, Capacitive Touch Screen which plays the role of shielding the internal electrical signal, 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, 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 capacitive touch screen can still accurately calculate the touch position.

Because the capacitance varies with the contact area and dielectric, 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.

Capacitive touch screen is based on the principle of capacitive touch to work and control of the screen, usually by the four-layer glass screen composite, Capacitive Touch Screen the inner surface and interlayer coated with a layer of ITO conductive layer, the outermost layer is only 0.0015 mm thick silica glass protective layer. The inner layer of ITO as a shielding layer, when the finger touch on the metal layer, as a result of the human electric field, the user and touch screen surface formed with a coupling capacitor, the inductive capacitance of the charge transferred to another capacitor, Capacitive Touch Screen by detecting the charge transfer amount to detect the size of the capacitance.

Characteristics of Capacitive touch screen

Accuracy: 99% accuracy.

Material: Completely scratch-resistant glass material (Morse hardness 7H), not susceptible to sharp scratches and wear, not affected by common sources of pollution, such as water, fire, radiation, electrostatic, dust or oil. Eye protection with goggles.

Sensitivity: Less than two ounces of force can be induced, less than 3ms fast response.

Clarity: Three kinds of surface treatment (Polish, Etch, Industrial) are available for selection. The MTBF of the SMT controller is greater than 572,600 hours (per milhandbook-217-f1).

Touch life: Any point can withstand more than 50 million times of touch, Capacitive Touch Screen once corrected cursor does not drift.

Capacitive touch Screen Notes

1. Do not use corrosive organic solvents to wipe the surface of touch screen. such as industrial alcohol.

2, touch screen part for glass products, Glass Corner is sharper, when assembling, please bring gloves/finger sets of work

3, touch screen parts for glass fragile products, Capacitive Touch Screen assembly do not exert a strong impact on the touch screen.

4, avoid directly take the lead to pick up the touch screen, to avoid the introduction of the part of the line pulling action.

5, the lead line to strengthen the plate position can not be bent.

6, the introduction of any part of the outlet is not allowed to fold phenomenon.

7, the lead line in the assembly, must be horizontal insertion, not in the reinforcement plate root fold insert.

8, take the product to put the single piece of operation, lightly take care, Capacitive Touch Screen avoid the product collision and scratched the surface of the product.

9, clean the product surface, please use soft cloth (buckskin) dipped in petroleum ether wipe.

10, touch screen surface for the touch surface, Capacitive Touch Screen that is the product front, the glass surface is not the touch surface, namely product back

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