touchscreen

Touchscreen is a display that enables direct interaction by touching the screen with a finger or stylus. Touch input is detected by sensors beneath the surface and converted into commands that control software and hardware.

The main technologies are resistive, capacitive, infrared, and surface acoustic wave. Resistive screens have two flexible layers separated by a gap; they register contact when pressed and work with any pointing object, but are less sensitive and offer limited multi-touch. Capacitive screens use a transparent conductive layer that detects changes in an electrostatic field; they are highly responsive, support precise multi-touch, and require a conductive input. Within capacitive types, projected capacitive sensors use a grid of electrodes for robust multi-touch. Infrared and surface acoustic wave systems detect touch by interrupting or disturbing a field or waves around the display and are common in larger displays and kiosks rather than handheld devices.

Touchscreens support direct manipulation of content through gestures such as tap, swipe, pinch, and rotate. They enable compact devices but can be prone to scratches, glare, and reduced performance in wet conditions; some models address these issues with protective coatings or glove compatibility.

History and usage: Touchscreens were developed in the 1970s and 1980s and achieved widespread consumer use with smartphones and tablets in the 2000s. Today they appear on smartphones, tablets, laptops, kiosks, ATMs, medical equipment, and car interfaces. Ongoing work aims to improve durability, accuracy, and haptic feedback, while expanding input methods and accessibility.