A light pen is a light-sensitive computer input pointing device shaped like a wand. It is connected to a visual display unit or CRT monitor and allows the user to modify data and text or make menu selections on the screen. Light pens became popular during the 1980s.
A light pen works like a touch screen, but it offers the user more ease of use and accuracy. Because the user can draw directly to the screen, light pens are used by graphics artists, though they are not as accurate as digitizing tablets. The pen works with CRT monitors but is not as compatible with projectors, LCD screens and other display devices.