Capacitive touch screen principle

Capacitive touch screen and resistive touch screen are two common touch screen technologies, which are very different in principle, structure and application. The following will introduce the principle, structure and characteristics of capacitive touch screen, and resistive touch screen comparison and analysis.

First, the principle of capacitive touch screen

Capacitive touch screen is the use of human charge or other conductive body capacitance changes to achieve touch positioning technology. The basic principle is to use the touch panel on the transparent conductive layer formed by the electric field, when the human body or other conductive body in contact with the touch panel, will change the distribution of the electric field, and thus be sensed, in order to calculate the touch coordinates.

Specifically, the capacitive touch panel consists of glass, a transparent conductive layer, and a coated insulating layer. The transparent conductive layer can be a material such as a silver nanowire grid, ITO film, or a grid structure. Electrode sensors are set up on the corners or edges of the touch panel, and they convert the changes in the electric field into electrical signals by scanning, which are then processed to finally determine the coordinate position of the touch.

Second, the structure of capacitive touch screen

Capacitive touch screen usually use glass as a touch panel substrate, coated with a transparent conductive layer, and covered with scratch-resistant coating. Transparent conductive layer is generally uniformly distributed throughout the touch panel, can be made through a fine grid of microwires or uniform coating and other methods. Conductive layer will be covered with a layer of coating insulation, used to protect the transparent conductive layer.

Third, the characteristics of capacitive touch screen 

High sensitivity: capacitive touch screen based on the principle of capacitance change, higher sensitivity to touch. No need to press hard when touching, gently touch can be operated.

Fast response speed: capacitive touch screen response speed is very fast, touch operation feedback is almost real-time.

Support multi-touch: Capacitive touch screen can detect multiple touch points at the same time and can realize multi-touch function. This allows users to use their fingers to zoom, rotate, swipe, and many other gestures.

High light transmission: Capacitive touch screen has very good light transmission, which hardly affects the display.

Wear-resistant: capacitive touch screen with wear-resistant coating, has a good wear resistance, long service life.

Fourth, the difference between capacitive touch screen and resistive touch screen

Working principle: capacitive touch screen is based on the principle of capacitance change, resistive touch screen is based on the principle of resistance change.

Touch method: capacitive touch screen adopts the non-pressure touch method, which can be operated with only a light touch. Resistive touch screen needs to apply a certain pressure to make the two resistive layers contact in order to be positioned.

Touch perception: Capacitive touch screens can perceive conductor contact without real physical contact. Resistive touchscreens require physical contact and can only sense objects that are conductive.

Sensitivity: Capacitive touch screens are more sensitive and require only a light touch when touching. Resistive touch screen requires a certain amount of pressure, so the sensitivity is lower.

Multi-touch: Capacitive touch screen supports multi-touch, can realize a variety of gestures. Resistive touch screen can only realize single touch.

Light Transmission: Capacitive touch screen has better light transmission, which hardly affects the display effect. Resistive touch screen will affect the display effect, need to increase the light transmission layer to protect.

Summarize:

Capacitive touch screen and resistive touch screen are two common touch screen technologies, they are very different in principle, structure and features. Capacitive touch screen uses capacitance change to realize touch positioning, high sensitivity, fast response speed, support multi-touch and other features make it widely used in modern intelligent devices.