You are now entering the PC Anatomy portal

A light pen is an obsolete, pen-shaped input device for Cathode Ray Tube (CRT) displays that uses a light-sensitive sensor to detect a specific point on the screen. When the pen's sensor detects the screen's refresh beam at a particular location, the computer can determine the pen's X,Y position to allow users to point, draw, or select objects directly on the screen. Light pens were a precise alternative to mice for interacting with menu-driven software and graphics on CRT monitors.

Input Device: Light pens are a type of input peripheral used for data entry.

CRT Specific: They are designed to work with CRT monitors and are not compatible with modern LCD screens.

Precision: Light pens offered a high degree of positional accuracy for screen-based interaction.

Context: They were a pioneering technology for human-computer interaction, providing a more intimate way to interface with displays than keyboards or mice.