The built environment is made up square and rectangular surfaces, such as walls and ceilings. This physical environment makes for mismatch with much of the lighting industry’s output: most luminaires produce a circular or oval, not a rectangular, beam. In many cases, such as downlighting applications, the effect of lighting a rectangular space with a circular beam is perfectly acceptable.
Certain professional and commercial lighting designs, however, call for a uniform rectangular beam. For instance, the walls of a corridor in a hotel or office may be beautifully and evenly washed with a series of rectangular beams from surface-mount, track-mount or recessed luminaires. Precisely positioned so that the vertical edge of one beam abuts the vertical edge of the adjacent beam, such fixtures can create the illusion of a continuous wall of light stretching into the distance. In these designs, even small variations within a beam, or between one beam and another, are highly undesirable. Uniformity and consistently high quality of light are therefore important attributes of fixtures with rectangular beams. The most common conventional lamp used in rectangular-beam fixtures is ceramic metal halide (CMH), which provides high efficacy and a uniform, consistent beam. While efficient and consistent, the quality of the light from CMH is often lacking, dimming is not possible and the lifetime pales in comparison to what is possible with LEDs. Conversely, the conventional approach to the design of LED fixtures is to use an array of white LEDs, but this can fail to offer the required uniformity within the beam or between one beam and another.
Clearly a union that combines the best attributes of CMH and LED would fill the gap. Recognizing the need of lighting designers to have a source they can use to light rectangular surfaces and also use for asymmetric uplighting and accent lighting led Xicato to create the XLM module. Superior to CMH in its quality of light, dimmability and lifetime, the XLM offers all the advantages of CMH with none of its drawbacks.
