The working principle of touch screen

The working principle of touch screen

A touch screen is an input device for a computer, which is different from a keyboard that can input and a mouse that can click. It allows users to make selections by touching the screen. Computers with touch screens require limited storage space, have few moving parts, and can be packaged. Touchscreens are more intuitive to use than keyboards and mice, and the training cost is also very low.

All touch screens have three main components. Processing user selected sensor units; A controller that senses touch and locates, as well as a software device driver that transmits touch signals to the computer operating system. There are five technologies for touch screen sensors: resistive technology, capacitive technology, infrared technology, acoustic technology, or near-field imaging technology.

Resistive touch screens typically consist of a flexible top film and a layer of glass as the base layer, isolated by insulation points. The inner surface coating of each layer is a transparent metal oxide. The voltage has a difference in each layer of the diaphragm. Pressing the top film will form electrical contact signals between the various resistance layers

Capacitive touch screens are also coated with transparent metal oxides and bonded to a single-layer glass surface. It is not like a resistive touch screen, where any touch generates a signal. A capacitive touch screen requires direct touch with a finger or contact with a conductive iron pen. The capacitance of fingers, or the ability to store charges, can absorb the current from each corner of the touch screen, and the current flowing through these four electrodes is proportional to the distance from the finger to the four corners, thus determining the touch point.