The difference between resistive and capacitive touch screens

Working principle of resistive touch screen

The resistive touch screen is mainly controlled by pressure sensing. It consists of a display screen and a resistive thin film screen that closely fits the display screen. This resistive film screen is usually divided into two layers. One layer is a base layer made of glass or plexiglass, and its surface is coated with a transparent conductive layer; the base layer is pressed with a hardened and scratch-resistant plastic layer that we usually contact directly. There is also a conductive layer inside the plastic layer, and the two conductive layers are separated. When we touch the screen with a finger or other objects, the two conductive layers come into contact, and the resistance changes. The controller judges the coordinates of the contact point and performs corresponding operations based on the specific changes in resistance.

Working principle of capacitive touch screen

Unlike resistive touch screens, capacitive touch screens use the current induction of the human body to work. The sensing screen of the capacitive touch screen is a four-layer composite glass screen. The inner surface and interlayer of the glass screen are each coated with a conductive layer, and the outermost layer is a thin layer of silica glass protective layer. When we touch the sensor screen with a finger, the electric field of the human body makes the finger and the surface of the touch screen form a coupling capacitor. For high-frequency current, the capacitor is a direct conductor, so the finger draws a small current from the contact point. . This current flows from the electrodes on the four corners of the touch screen, and the current flowing through these four electrodes is proportional to the distance from the finger to the four corners. The controller obtains the position of the touch point by accurately calculating the ratio of these four currents. .

Compared with traditional resistive touch screens, capacitive touch screens have the following advantages:

1. Operation is novel. The capacitive touch screen supports multi-touch, the operation is more intuitive and interesting. Not easy to touch by mistake. Since the capacitive touch screen needs to sense the current of the human body, only the human body can operate it, and it will not respond when touched with other objects, so the possibility of accidental touch is basically avoided. High durability. Compared with resistive touch screens, capacitive touch screens have better performance in terms of dustproof, waterproof, and wear resistance.

Four-wire resistive screen

When the two transparent metal layers of the four-wire resistance analog technology work, each layer increases a constant voltage of 5V: one vertical direction and one horizontal direction. A total of four cables are required. Features: High resolution, high speed transmission response. Surface hardness treatment reduces scratches, scratches and anti-chemical treatment. With smooth and matte finish.

Five-wire resistive screen

The base layer of the five-wire resistive technology touch screen adds the voltage fields in both directions to the conductive working surface of the glass through the precision resistance network. We can simply understand that the voltage fields in the two directions are added to the same working surface in time-sharing. The outer nickel-gold conductive layer is only used as a pure conductor, and the position of the touch point is measured by the method of detecting the X-axis and Y-axis voltage values of the inner layer ITO contact point after touching. The five-wire resistive touch screen requires four leads on the inner layer of ITO, and only one conductor on the outer layer. There are 5 lead wires for the touch screen. Features: High resolution, high-speed transmission response. The surface hardness is high, reducing scratches, scratches and anti-chemical treatment. 30 million times at the same point can still be used. Conductive glass is the substrate medium.