The following are the advantages of touch screens:
① Various operations such as zooming in and moving can also be realized by software without physical buttons.
② Multi-touch (more than two points) can realize various inputs such as zoom in and zoom out.
③ The displayed operation object is the same as the input object, which has intuitive operability.
④ The integration of input and display can realize the miniaturization of the machine, and the degree of freedom of design is relatively high.
⑤ There will be no gaps like keyboards, switches, etc., which can enter garbage, dust, water, etc., it is not easy to be damaged and easy to maintain.
The above are only the advantages of touch screen, but it also has the following disadvantages:
① Not suitable for fast input such as keyboard, mouse and buttons.
② Directly touch the display, the screen is easy to be contaminated, and it is difficult to read information; it is easy to cause misoperation due to scratches.
③ There is no click feeling like buttons and a mouse, so the input action will become awkward (there are also touch screens that can get a click feeling).
④ It is difficult for blind people to use it, so it needs to be used together with voice instructions and keys, or to specify the touch position.
In addition, the touch screen has many detection methods, and the use, size, price, system structure, etc. of the touch screen of different detection methods are different. Only by understanding this well can you be able to detect whether your device can use the touch screen.
Defects of capacitive touch screen
The light transmittance and clarity of capacitive touch screens are better than that of four-wire resistive screens. Of course, they cannot be compared with surface acoustic wave screens and five-wire resistive screens. Capacitive screens reflect serious light, and the four-layer composite touch screen of capacitive technology has uneven light transmittance to light of various wavelengths, and there is a problem of color distortion. Due to the reflection of light between layers, image characters are also blurred. In principle, the capacitive screen uses the human body as an electrode of a capacitor element. When a conductor close to the working surface of the interlayer ITO is coupled with a sufficient capacitance value, the current flowing away is sufficient to cause the capacitive screen to malfunction . We know that although the capacitance value is inversely proportional to the distance between the poles, it is directly proportional to the relative area and is also related to the insulation coefficient of the medium. Therefore, when a large area of the palm or a hand-held conductive object is close to the capacitive screen instead of touching, it can cause the capacitive screen to malfunction. In wet weather, this situation is especially serious. Hold the display with the palm close to the display 7 cm Within 15 cm of the body close to the display can cause the capacitive screen to malfunction. Another disadvantage of capacitive screens is that there is no response when touched with gloved hands or holding non-conductive objects. This is because a more insulating medium is added. The main disadvantage of the capacitive screen is drift: when the ambient temperature and humidity change, and the environmental electric field changes, it will cause the capacitive screen to drift and cause inaccuracy. For example: the temperature of the display will rise after power-on, which will cause drift: when the user touches the screen, the other hand or the side of the body will drift close to the display; larger objects near the capacitive touch screen will drift back after being moved. It will cause drift; the reason for the drift of the capacitive screen is due to technical inadequacy. Although the environmental potential surface (including the user's body) is far away from the capacitive touch screen, it is much larger than the area of the finger. They directly affect the determination of the touch position . In addition, in theory, many relationships that should be linear are actually non-linear, such as: the total amount of current drawn by people with different weights or different degrees of finger wetness is different, and the change in the total current and the changes in the four sub-currents It is a non-linear relationship. The four-corner custom polar coordinate system adopted by the capacitive touch screen has no origin on the coordinates. After drifting, the controller cannot detect and recover. Moreover, after the completion of 4 A/Ds, there are four points. The calculation process from the value of the flow rate to the X and Y coordinate values of the touch point on the Cartesian coordinate system is complicated. Since there is no origin, the drift of the capacitive screen is accumulated, and calibration is often required at the work site. The outermost silica protective glass of the capacitive touch screen is very scratch-resistant, but it is afraid of nails or hard objects. If a small hole is knocked out, it will damage the interlayer ITO, whether it is damage to the interlayer ITO or during installation and transportation. With the ITO layer on the inner surface, the capacitive screen cannot work normally.
