Touchscreens

A touchscreen is an input and display device that allows users to interact directly with what is displayed by touching the screen. Touchscreens are widely used in consumer electronics such as smartphones, tablets, laptops, kiosks, and point-of-sale terminals, as well as in industrial and automotive applications.

There are several underlying sensing technologies. Resistive touchscreens consist of two flexible layers separated by a gap; touching the screen causes electrical contact, which is detected by a controller. Capacitive touchscreens sense changes in an electrostatic field; they are typically more sensitive and support multi-touch, but usually require a conductive input such as a finger. Variants include surface-capacitive and projected-capacitive designs. Infrared touchscreens use an array of light beams around the screen edges to detect interruptions caused by touch, enabling glove and stylus use in some configurations. Surface acoustic wave and optical touch systems use acoustic or optical methods to determine touch position. Modern devices often rely on projected-capacitive technology for high sensitivity and large multi-touch capability.

Touchscreens support a range of input methods beyond single taps, including multi-finger gestures (pinch, zoom, rotate) and, in many devices, stylus input for drawing or handwriting. In-display fingerprint sensors and haptic feedback are common complements in contemporary screens.

Advantages of touchscreens include intuitive use, faster interaction, and compact form factors. Limitations can include durability concerns, susceptibility to scratches or fingerprints, calibration requirements, and higher power consumption in some designs. They continue to evolve with improvements in durability, accuracy, and integration with display and sensing layers.