The resistive touch screen is controlled by the pressure sensing. The main part of the resistance touch screen is a resistive thin film screen which is very matched with the surface of the display, which is a multi-layer composite film, which is coated with a layer of glass or a hard plastic flat plate as a base layer, the surface of which is coated with a transparent oxidation metal (transparent conductive resistance) conducting layer, the upper surface of the resistance touch screen is coated with a layer of transparent oxidation metal (transparent conductive resistance) conductive layer, the upper surface of the resistance touch screen is coated with a layer of outer surface hardening treatment, the smooth and scratch-resistant plastic layer, and the inner surface of the conductive layer is also coated with a coating layer, and a plurality of fine (less than 1/1000 inch) transparent isolation points are arranged between them to separate the two layers of conductive layers. When the finger touches the screen, the two layers of conductive layers are in contact with the touch point position, the resistance changes, the signals are generated in both the x and y directions, and then the touch screen controller is sent. The controller detects this contact and calculates the position of (x, y) and operates according to the mode of the analog mouse. This is the most basic principle of the resistance technology touch screen. Resistance screen performance characteristics: they all are a working environment that is completely isolated from the outside, not afraid of dust, water vapor and oil pollution, can be touched by any object, can be used for writing and drawing, which is relatively large.
The precision of the resistance touch screen depends only on the accuracy of a/ d conversion, so that the precision of the resistance touch screen can be easily reached by 4096 * 4096. The five-wire resistance is superior to the four-wire resistance in the guaranteed resolution accuracy, but the cost is high, and therefore, the cost is high, and the common drawback of the high-resistance touch screen is that the outer layer of the composite film is made of a plastic material, the people who do not know are too strong, or a sharp touch is used to scratch the whole touch screen to cause the scrap. However, within the limit, the scratch can only damage the outer conductive layer, the scratch of the outer conductive layer is not related to the five-wire resistance touch screen, and is fatal to the four-wire resistance touch screen. The capacitive touch screen is a four-layer composite glass screen, the inner surface and the interlayer of the glass screen are each coated with a layer of ito, and the outermost layer is a thin-layer laminated soil glass protective layer, the interlayer ito coating acts as a working surface, four electrodes are led out at four corners, and the inner layer ito is a shielding layer to ensure a good working environment. When the finger touches the metal layer, due to the electric field of the human body, the user and the surface of the touch screen are formed with a coupling capacitor, and for the high-frequency current, the capacitor is a direct conductor, so that the finger draws a small current from the contact point. This current flows out of the electrode on the four corners of the touch screen, and the current flowing through the four electrodes is directly proportional to the distance of the finger to the four corners, and the controller obtains the position of the touch point by the accurate calculation of the four current ratios.
The light transmittance and the definition of the defective capacitance touch screen of the capacitive touch screen are superior to the four-wire resistor screen, and of course, the capacitive screen can not be compared with the surface acoustic wave screen and the five-wire resistance screen, the reflection of the capacitive screen is serious, and the four-layer composite touch screen of the capacitive technology is not uniform in light transmittance of each wavelength light, and the problem of color distortion is solved, and the blurring of the image characters is also caused due to the reflection of the light rays between the layers. A capacitive screen is used in principle to use a human body as an electrode of a capacitor element, and when a conductor is close to a capacitor with a sufficient amount of capacitance to be coupled to the working face of the interlayer, the current flowing is sufficient to cause a malfunction of the capacitive screen. We know that the capacitance value, although inversely proportional to the inter-pole distance, is proportional to the relative area and is also related to the dielectric constant of the medium. Therefore, when a large area of the palm or the hand-held conductor is close to the capacitive screen rather than a touch, the malfunction of the capacitive screen can be caused, and in a wet weather, the situation is particularly severe, the display is held, the palm is close to the display, or the body is close to within 15 cm of the display, the malfunction of the capacitive screen can be caused. Another disadvantage of the capacitive screen is that there is no response when a glove-worn hand or a hand-held non-conductive object is touched because a more insulating medium is added. The main disadvantage of the capacitive screen is the drift: when the ambient temperature and the humidity are changed, the change of the ambient electric field can cause the drift of the capacitance screen, which is not accurate. For example, the temperature rise of the display can cause the drift when the user touches the screen, while the other hand or the body side is close to the display to drift; the large object in the vicinity of the capacitive touch screen is moved back to the drift; when you touch, if someone is around to watch, the drift can be caused; the drift reason of the capacitive screen belongs to the prior art, and the environmental potential surface (including the body of the user) is far away from the capacitive touch screen than the finger area, so that the measurement of the touch position is directly affected. In addition, the relationship between the change of the total electric flow and the change of the four sub-electric flow is different, and the change of the total current flow and the change of the four partial electric flow are non-linear, and the custom pole coordinate system of the four corners adopted by the capacitive touch screen is not in any coordinate. The most out of the capacitive touch screen can be used to protect the glass from scratch, but for fear of the knocking of the nail or the hard object, a small hole can damage the interlayer ito, and the capacitive screen can not work normally, whether the interlayer ito is damaged or the ito layer of the inner surface is damaged during the transportation process.