A spiral is made of clear plastic rod. Light enters the end of the rod and travels around the spiral by reflection from the sides at the critical angle, eventually emerging at the other end of the spiral. these light pipes transmit light through total internal reflection. With a light pipe, light can be made to bend around corners. The B&L light wire is a bundle of thin glass fibers, each about 15 microns (15 x 10-6 meter) in diameter. Each fiber is clad in a coating of lower refractive index than itself and transmits light by a process of total internal reflection. Large numbers of these high optical quality fibers are bundles together to make a flexible "wire". The ends are boneded, ground and polished. The entire bundle is encased in a flexible aluminum sheathing to protect the fibers from crushing or severe bending. To use either the light pipe or the sheathed fiber bundle, use the Burton light source with the diaphragm at the lens.
|Light pipe and optical fiber