Disadvantages of capacitive touch screen

- Jul 19, 2018-

Capacitive touch screen transmittance and clarity than the four-line resistance screen, of course, and surface acoustic screen and five-wire resistance screen compared.

Capacitive screen reflection is serious, and, capacitance technology of the four-layer composite touch screen for each wavelength of light transmittance is uneven, there is the problem of color distortion, due to the light in the reflection between the layers, but also caused by blurred image characters.

Current: Capacitive screen on the principle of the human body as a capacitor element of an electrode used, when a conductor close to the sandwich Ito face coupled with sufficient capacity of capacitance, the flow of the current is enough to cause the capacitance screen error action. Although the capacitance value is inversely proportional to the distance between the poles, it is in direct proportion to the relative area and is also related to the dielectric insulation coefficient. Therefore, when the larger area of the palm or hand-held conductor near the capacitive screen rather than touch can cause the capacitor screen error action, in humid weather, this situation is particularly serious, hand-held live monitor, palm close to the monitor within 7 centimeters or the body close to the monitor within 15 cm can cause the capacitor screen error action.

Another disadvantage of the capacitive screen is that there is no response when touching a gloved hand or holding a Non-conductive object, because it adds more insulating media. Drift: The main disadvantage of the capacitive screen is drift: when the ambient temperature, humidity changes, the environmental electric field changes, will cause the drift of the capacitive screen, resulting in inaccurate. For example: After the boot, the temperature rise of the monitor will cause drift: the user touches the screen while the other hand or side of the body is near the monitor drift; the capacitive touch screen will drift after the larger object moves, the user touch if someone around to watch will also cause drift; the drift of the capacitive screen is technically congenitally deficient,

The environmental potential surface (including the user's body), although far away from the capacitive touch screen, is much larger than the finger area, and they directly affect the measurement of the touch position. Other: In addition, theoretically many of the relationships that should be linear are actually non-linear, such as: the total electrical flux that is absorbed by people with different weight or the degree of wetting of the fingers is different, and the change of total electric flow and the change of four distribution is non-linear. The Capacitive touch screen uses this four-angle custom polar coordinate system to have no origin on the coordinates, after drift, the controller is unable to detect and recover, and after 4 A/d is completed, the calculation of the x and Y coordinate values of the four-cent flow value to the touch point in the rectangular coordinate system is complex. Since there is no origin, the drift of the capacitive screen is cumulative, and the calibration is often required at the work site. Capacitive touch screen The outermost silica protective glass is very good for scratch resistance, but afraid of the nails or the hard objects of the percussion, tapping a small hole will hurt the sandwich Ito, whether the wound and sandwich Ito or the installation of the transport process slander and the inner surface ITO layer, the capacitive screen can not work properly.