Light Pen

Traditionally, most people navigate around their computers with a mouse. The mouse can be either attached to the computer or wireless, and serves as the point and click (and in many cases drawing) tool for PC users. There are other ways to communicate with the computer, however, and one of these is called a light pen. A light pen is a computer input device that is used hand in hand with the computer monitor. It is called a light pen because its action is activated by light, therefore it is light sensitive. It is important to note, however, that a light pen cannot work with LCD screens, only traditional monitors. It may be hard to imagine, but the light pen actually became moderately popular in the early 1980’s when it was first used in sync with synthesized music. Another interesting fact about this modern marvel is that it is used in the popular television game show Jeopardy during the final round when contestants are writing their final questions on the blue screens for the winning bid.

Because of its name, many people might be led to believe that light pens emit or project some sort of light from them, and that is what causes the interaction between the pen itself and the computer screen. The fact is, however, that it is just the opposite. The light pen feeds off of light being emitted from the computer screen. Once the user pushed the button that is attached to the pen, wherever it is pointed illuminates on the screen. Another name for the light pen is “selector pen”, since whatever it is pointed at selects the object on the screen. This ingenious little invention was actually created in the 1950’s and is still commonly used in many homes and industrial environments today.