Illumination systems are used in a variety of applications. Home and industrial applications often require light to be made available. Similarly, aircraft, marine, and automotive applications often require high intensity light beams for illumination. Traditional lighting systems have used electrically powered filament or arc lamps, which sometimes include focusing lenses and/or reflective surfaces to collect the emitted light and direct it as a light beam to the intended target.
In certain applications, however, it may be advantageous to remove the light source from an environment where electrical contacts are undesirable, that is subject to physical shock or damage, or where space is limited. In response to such needs, illumination systems have been developed that use light guides to guide the light from the light source to a desired illumination point. One current approach is to use a single, bright source or a cluster of light sources to illuminate the input end of a light guide, such as a large core plastic fiber. In another approach, the single fiber may be replaced by a bundle of fibers. These methods are generally inefficient, with approximately 70% of the generated light being lost in some cases. In multiple fiber systems, some of the loss is attributable to the dark spaces between fibers. In a single light guide approach, a light guide having a large enough diameter to capture the amount of light needed for bright lighting applications becomes thick and, therefore, loses flexibility.
Some illumination systems use lasers as light sources, to take advantage of the coherent light output and high coupling efficiency to light guides. Laser sources, however, are expensive and typically produce light at a single wavelength, which is less useful where the requirement is for broadband illumination.
There is, therefore, a need for an illumination system that can efficiently deliver high intensity illumination, at reasonable cost, using a remote light source.