Light Pipes

A light pipe is a long cylinder shaped piece of glass, or other material, that is used to transmit light along its length.  While travelling through the light pipe, the light is reflected at various points and gets mixed together thus homogenizing the light and providing more uniform intensity.  A light pipe is a large scale optical fiber and can be used in a similar manner to conduct light from one location to another, such as from an led to a light indicator on an instrument.