Published In April 2001
Glass fiber optics lighting is composed of three compatible parts. First-time users should consult with a qualified supplier to create a bill of materials. A light source: (called an illuminator or projector) is conveniently located in a readily accessible place for relamping. It is the size of a large shoebox and can be used indoors or outdoors. Areas can be relamped without disturbing displays or traffic. The dichroic lamp can be tungsten halogen or metal halide. The latter is the most dependable, long lasting, and energy-efficient. It has a lamp life of 6,000 hours, and uses one-fourth the energy of halogen. Color temperatures range from 4,000K to 5,200K. One lamp powers multiple points of light. Most units include a silent fan to dissipate heat from the lamp. A harness: an octopus-like bundle of assorted lengths and sizes of very flexible glass light guides (“tails”) attached to a light source. The glass should be of highest quality and have a maximum attenuation of 200 dB/kilometers, measured at 450 nanometers. End-emitting tails are used for functional long-term architectural applications (task, display, architectural contours, and even ambient illumination). Side-emitting tails are only for decorative purposes and are also a substitute for neon. Glass harnesses are shipped fully assembled and need only be inserted into the light source. No cutting, polishing, or splicing is needed, as with plastic, making for simpler installation. Sheathing is Megolon, a proprietary halogen-free material that is self-extinguishing and does not emit poisonous fumes if burning, like plastic coverings. No electricity flows through the very flexible tails—only light rays. A tail is composed of multiples of about 400 glass strands, each around 50 microns, the size of a human hair. The wide selection of these thin light guides, from size 1 (400 strands) to size 96 (96 x 400), or larger, offers great choices of light level. Usual tail diameters range from 1.0 mm to 12.5 mm (½ inch). Size of footprint of light is a factor of the tail size. Throw distances of 100 feet are possible with suitably sized tails. Distances of at least 72 feet can be served with tails emerging in opposite directions out of a centrally located light source. Over that distance, present-day glass fibers may start experiencing color shift. However, the newer improved fibers with reduced attenuation are brighter, and light rays can travel longer before this normal physical characteristic appears. Once the required sizes and lengths of tails are computed, the factory-assembled harness is simply inserted into the light source. Then the tails are fished through interstitial spaces, as for any other lighting job, to emerge exactly where points of light are needed. For flexibility of use, a harness can be easily changed for another with different combinations of light guides. Fittings: If required, there is a large variety of miniaturized lenses and holders for collimating, diffusing, wall-washer, zoom, framing projector, and downlight uses. Combinations of lenses can be customized. The fittings are merely screwed onto the threaded metal ferrules at the end of the light guides. They can be changed at any time for other lenses. There are many methods of securing the focus of the lenses and holders in place, safe from vibration or accidental dislodging. Special effects: In addition, color, motion, and dimming can also be provided. Each tail can be a different color, or a glass dichroic color filter can be inserted into the light source to change the entire harness. Theatrical computers can provide multiple automatic effects.