What is the difference between a capacitive touch screen and a resistive touch screen?

Capacitive touch screen is a layer of transparent special metal conductive material pasted on the glass surface. When a finger touches the metal layer, the capacitance of the contact changes, so that the frequency of the oscillator connected to it changes, and the touch position can be determined to obtain information by measuring the frequency change. Because the capacitance changes with temperature, humidity, or ground conditions, its stability is poor, and drift often occurs.


A resistive touch screen is a sensor. It is basically a thin film plus glass structure. The adjacent surface of the thin film and glass is coated with an ITO (nano-indium tin metal oxide) coating. ITO has good conductivity and transparency. Sex. When touch operation is performed, the ITO on the lower layer of the film will contact the ITO on the upper layer of the glass, and the corresponding electric signal will be sent out through the sensor, which will be sent to the processor through the conversion circuit, which will be converted into the X and Y values on the screen by calculation, and the completion point The selected action is displayed on the screen.


  working principle: 


Capacity technology CTP (Capacity Touch Panel) uses the human body's current sensing to work. The capacitive screen is a four-layer composite glass screen. The inner surface of the glass screen and the interlayer are each coated with a layer of ITO (nano-indium tin metal oxide). The outermost layer is a protective layer of silica glass with a thickness of only 0.0015 mm, and the interlayer ITO coating is used. As the working surface, four electrodes are drawn from the four corners, and the inner layer of ITO is the screen layer to ensure the working environment.


The working principle of the resistive touch screen is to achieve the operation and control of the screen content through the principle of pressure sensing. The part of the touch screen screen is a multilayer composite film that fits the surface of the display. The first layer is glass or plexiglass. The bottom layer, the second layer is a barrier layer, the third layer is a multi-resin surface layer, the surface is also coated with a transparent conductive layer, and the top is covered with a hardened, smooth and scratch-resistant plastic layer.


Generally speaking, the capacitive touch screen is a human-computer interaction mode that supports multi-touch. The ordinary resistive touch screen can only perform single-point touch.


For example: Apple iphone, Nokia N8, Nokia E7 are capacitive touch screens, which can be operated by touching the screen with both hands at the same time.


Nokia 5800, n97; HTC d600 s90, 5230, etc. are resistive touch screens, which can only be operated at a single point.