Mobile phone touch screen light transmittance and clarity is better than that of 4 line resistance screen, of course also cannot and surface acoustic wave screens and five line resistance than capacitance screen reflection is serious, and the four layers of capacitance technology composite touch screen for each wavelength of light transmittance is not uniform, has the problem of color distortion, due to the reflection light between the layers, also caused the image fuzzy characters.
Capacitance screen on the principle of human body as a capacitor element one electrode is used, when there is a close to the conductor and the interlayer coupling between ITO face out enough capacity value of capacitance, escape the current is enough to cause misoperation of capacitance screen as we know, although capacitance is inversely proportional to the polar distance, but is proportional to the relative area, and also related to the insulation of the coefficient of medium, therefore, when a large palm or carrying conductor came near the capacitance screen not touch can cause the misoperation of capacitance screen, in the humid weather, this situation is particularly serious, Holding the palm of the hand to within 7 cm of the monitor or the body to within 15 cm of the monitor can cause the capacitor screen to misbehave.
Another drawback of capacitive screens is that they do not respond when touched by a gloved hand or an unconductive object in hand, due to the addition of a more insulated medium.
The bigger disadvantage of capacitive screen is drift: when the ambient temperature and humidity change and the environmental electric field changes, the capacitor screen will drift, causing inaccuracy. For example, the temperature rise of the monitor will drift after the user starts up: when the user touches the screen, the other hand or side of the body will drift. The larger objects near the capacitive touch screen move back and drift, and if someone comes around to watch when you touch them, they drift. Although the environmental potential surface (including the user's body) is far away from the capacitive touch screen, it is much larger than the finger area. In addition, they directly affect the measurement of the touch position. In addition, in theory, many of the relationships that should be linear are actually non-linear. Different weight or wetting degree different people suck finger total power flow is different, and the change of total power flow and four the relationship between the change in the flow distribution is nonlinear, capacitive touch screen using the four corners of the custom of polar coordinates is not coordinate origin, after drifting controller cannot detect and recovery, and 4, after the completion of A/D by four shunt amount of value to the touch point on the rectangular coordinate system x, y coordinates calculation process with no complex origin, capacitive touch drift is cumulative, capacitive touch screen at the scene of the work also often need calibration the outermost silica glass scratch resistant protection is very good, However, if the nail or hard object is knocked, a small hole will hurt the interlayer ITO. Whether the interlayer ITO is damaged or the inner surface ITO is damaged during transportation, the capacitive screen will not work properly.