Light pens are designed to detect light emitted by an illuminated area such as a computer monitor. The pen glows as a result of the light that comes from the illumination source. The light pen is like a mouse, but the cursor can be moved more directly by pointing at the cursor with the light pen itself, according to Webopedia.
Corded Light Pens
Light pens are user friendly because they are intuitive. To select something, point at the screen. However, light pens have never caught on because most computer users have found the mouse and the touchpad to be easy enough to use. Most older light pens come with a cord that attaches to the back of the pen. While these kinds of pens do not have to be recharged, the cord can be cumbersome.
Battery Light Pens
The Cross light pen shines when it is used. The pen produces a bright light and can last a long time on its battery. The battery makes this type of pen more efficient to use, though most computers do not come with the software drivers for it. The drivers must be downloaded or installed from a CD that comes with the pen.
"Light pen" is also a type of pen that allows designers to sketch using light. The light pen allows sketching in 3-D. The designer decides on a 3-D model exactly where the light source will be and can then see 3-D representations of how the light affects the surrounding area, according to the University of Washington. Then the designer can choose the light fixture that would be the most useful for that particular area.
The light pen was originally useful for drawing objects on a screen. However, the pen did not draw in high resolution and was not comfortable to use since the illustrator had to reach forward to draw on the screen. Tablets have replaced the light pen as the drawing tool used to create signatures and graphic art. With the tablet, the illustrator uses a stylus and draws over the flat device. The learning curve for the tablet might be higher than for the light pen because illustrators are not drawing on the screen itself but on the tablet.
LED Light Pen
Another variation is the LED light pen. This pen produces bright colors when it is squeezed. The colors serve no practical purpose but are just for the amusement of the user. This type of pen is refillable, according to Kim's Store.