Computer Input Device: Light Pen

Light Pen is an input device that utilizes a light-sensitive detector to select objects on a display screen. It is a computer input device in the form of a light-sensitive wand used in conjunction with the computer’s CRT monitor. It allows the user to point to displayed objects, or draw on the screen, in a similar way to a touch screen but with greater positional accuracy. The light pen works by sensing the sudden small change in brightness of a point on the screen when the electron gun refreshes that spot.