Capacitive Touch-screen Supports Multi-touch

- Sep 19, 2017-

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.

Capacitive touch screen structure is mainly in the glass screen coated with a transparent film body layer, and then in the conductor layer with a protective glass, double glass design can completely protect the conductor layer and sensor, and the transmittance is higher, but also better support multi-touch.

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 inversely proportional to the distance from the finger to the electrode, and 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, Capacitive Touch Screen more effectively prevent external environmental factors on the touch screen, Capacitive 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, 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 a four-layer composite glass screen, Capacitive Touch 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, four electrodes are drawn on four corners, Capacitive Touch Screen 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, Capacitive Touch Screen for high-frequency current, the capacitance is direct conductor, so the finger from the contact point to suck away a very small current. This current flows from the electrodes on the four corners of the touchscreen, and the current of the four electrodes is proportional to the distance between the fingers and the four corners, and the controller obtains the position of the touch point by accurate calculation of the four current ratios.

Capacitive touch screen to achieve multi-touch, by increasing the mutual capacitance of the electrode, simply put, the screen block, in each region set up a set of mutual capacitor modules are independent work, Capacitive Touch Screen so the capacitive screen can be independently detected by the various regions of the touch control situation, after processing, simply to achieve multi-touch control.

Capacitive touch screen is the use of the body's current induction work. The capacitive screen is a four-layer composite glass screen, the inner surface and interlayer of the glass screen are coated with a layer of ITO (nanometer indium tin metal oxide), the outermost layer is only 0.0015mm thick silica Glass protective layer, interlayer ito coating for working face, Four corners lead to four electrodes, Capacitive Touch Screen inner layer Ito is screen layer to ensure working environment When the user touches the capacitive screen, because of the human electric field, the user's finger and face form a coupling capacitor, because of the high frequency signal on the working surface, the finger absorbs a very small current, which flows from the electrodes on the four corners of the screen, and theoretically flows through four electrodes in proportion to the distance from the finger to the four corners, The controller obtains the position by the precise calculation of four current proportions. can achieve 99% accuracy, with less than 3ms response speed.


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