Introduction Of Capacitive Touch Screen

In principle,  the capacitor screen USES the human body, as an electrode of a capacitor element.  When a conductor is coupled with enough capacitance value between the interlayer ITO working face and the conductor, the current will be enough to cause the power screen to Improper operation.

The capacitive touch screen is coated with thin electrodes on all sides of the touch screen,  that form a low voltage ac electric field in the conductive body. When touching the screen,  due to the human electric field,  a coupling capacitor will be formed between the finger and the conductor layer,  and the current from the four-side electrode will flow to the contact. The strength of the current is proportional to the distance between the finger and the electrode,  and the controller behind the touch screen will calculate the ratio and strength of the current to accurately calculate the position of the touch point. The double glass of the capacitive touch screen can not only protect the conductor and sensor,  but also effectively prevent the impact of external environmental factors on the touch screen.  Even if the screen is stained with dirt,  dust or oil,  the capacitive touch screen can still accurately calculate the touch position.

Capacitive touch screen is a transparent layer of special metal conductive material on the glass surface.When a finger touches the metal layer, the capacitance of the contact will change, causing the frequency of the oscillator connected to it to change. By measuring the frequency change, the position of the touch can be determined and information can be obtained.Because capacitance varies with temperature, humidity or grounding, its stability is poor and drift often occurs.The touch screen is suitable for the debugging stage of system development.

Defect of capacitive touch screen:

Capacitive touch screens offer better light transmittance ,and clarity than four-wire resistive screens,  and certainly not as good as surface acoustic or five-wire resistive screens.  The capacitor screen reflects light seriously.  Moreover,  the four-layer composite touch screen of capacitor.  technology has uneven light transmission to light of all wavelengths, and color distortion.  The reflection of light between each layer also causes the blurring of image characte.

In principle,  the capacitor screen USES the human body as an electrode of a capacitor element.  When there is a conductor coupling enough,  capacitance between the interlayer ITO working face and the conductor,  the current flowing away is enough to cause the capacitor screen to misoperate.

We know that the capacitance value,  although inversely proportional to the distance between the poles, that is proportional to the relative area,  and is also related to the insulation coefficient of the medium.  So when large-area hand power IC.  or carrying conductor objects close to the capacitance screen,  when not touch can cause the misoperation of capacitance screen,  in the wet weather,  this situation is particularly serious, walking in monitor,  the palm of your hand close to 7 cm monitor rectifier transformer within or near the display body within 15 cm can cause misoperation of capacitive screen.  Another disadvantage of capacitive screens is that they do not respond to touch with a gloved hand , or handheld object that is not conductive because of the addition of a more insulating medium.

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