Touch screen is a technology that allows you to use IT devices more intuitively by clicking or dragging the desired location on the screen.
There are several types of touch screens depending on the detection method.
- Resistive touch panel: It is composed of two touch screens with resistance. When the touch screen is pressed, the two sheets are in contact with each other. By measuring the resistance value, you can know the coordinates. It is difficult to implement multi-touch.
- Ultrasonic touch panel: It is composed of a speaker that outputs ultrasonic waves and a detection sensor. If there is an object(such as a finger) that interferes with the progress of the ultrasound, the coordinates are determined.
- Infrared touch panel: It consists of an LED that outputs infrared light and a photoelectric device. If there is an object(such as a finger) that interferes with the progress of the infrared ray, the corresponding coordinates are determined.
- Capacitive touch screen: Coordinates are sensed using the amount of change in capacitance on the screen. It is difficult to manipulate with a non-dielectric (leather gloves, nails, general stylus pen, etc.).
4-wire resistive touch screen
“4-wire resistive touch screen” has long rod-shaped contacts printed on the corners of the upper and lower transparent electrodes.
It uses only 4 wires to detect touch points on a 2-Dimensional plane.
If you apply an electric field on one plane and then measure the voltage on the other, you can find the pressed point.