LED Light as Good as Halogen: the Xicato LED Spot Module
October 13, 2010
While in California two weeks ago, I visited the headquarters of Xicato, one of the most exciting companies in the burgeoning LED (light-emitting diode) lighting industry. CEO Menko DeRoos explained the company's modular approach to LED lighting and demonstrated the exceptional light quality that is achieved with their system.
To date, Xicato has been focusing on replacements for small MR-16 halogen lamps, defining a very specific niche for the company. The company does not itself manufacture light fixtures; it supplies the LED components to those manufacturers. The first products were shipped to fixture manufacturers in January, 2009, and the company is working with about 60 fixture manufacturers worldwide today.
The three-year-old firm has pioneered a number of significant advances in the development of these MR-16 replacements. For starters, the company created the module category in LED lighting--an approach that is now being widely copied by other manufacturers. This approach allows fixture manufacturers to quickly prototype and efficiently produce LED fixtures. Using just three screws, the LED module is secured to a heat sink for carrying away unwanted heat--a key requirement with LED lighting--and interchangeable reflectors with various beam-spreads can be easily secured to that LED module.
"Literally in a day they [fixture manufacturers] can build a prototype," DeRoos told me. "We try to shrink the time to market." Xicato currently offers LED modules with outputs of 400, 700, and 1,000 lumens, and they will soon be introducing 1,300- and 2,000-lumen modules. All of these modules have the same dimensions, making fixture design very easy.
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The second advance pioneered by Xicato is "remote phosphor" technology in which the phosphors are separated from the actual LED light sources. This approach allows the company to use fairly standard, off-the-shelf LEDs (from quality LED manufacturers Philips, Cree, and Osram), skip the laborious "binning" process in which light output of individual LEDs is color-matched, and generate highly consistent white light through the phosphor design.
The company's standard XSM modules achieve a color rendering index (CRI) of a respectable 81, while their XSM Artist Series achieves a truly remarkable CRI of 98--virtually identical to that of halogen lamps. Perhaps more significant, the variability of light color has been dramatically reduced. DeRoos demonstrated how much color variability is permitted with ANSI and NEMA standards and then the maximum variability permitted by Xicato's XSM specifications (see chart); the differences were remarkable. In technical terms, Xicato maintains color consistency within two MacAdam ellipses, while industry standards for LED binning allow for seven MacAdam ellipses (this will mean something to lighting designers).
A key part of Xicato's success has been their driving commitment to quality. Their products are tested at 85°C and 85% relative humidity--significantly more extreme conditions than what most manufacturers submit their products to. Xicato's product efficacy (lumens per watt) specifications are based on operation at 70°C--actual worst-case conditions that fixtures are likely to experience--while efficacies of LED lights from some manufacturers are measured at lower temperatures (resulting in unrealistically high efficacy estimates).
The efficacy of Xicato LED modules today is good, but not exceptional. The highest efficacies of Xicato modules are in the 45-55 lpw range. In the Artist Series, efficacies drop to the range of 33-40 lpw. DeRoos's philosophy is to get the performance and quality up to a high level, then focus attention on improving the efficacy. As higher-efficacy LEDs become available, the energy performance of Xicato modules will continue to improve--while the company maintains the quality they are quickly becoming known for. DeRoos says the efficacy of company's LED modules will improve 10-15% next year.
In introducing products, Xicato worked first with European fixture manufacturers, because of both the higher cost of electricity there and the willingness of Europeans to spend more for quality products. Among U.S. fixture manufacturers using Xicato LED modules is Lighting Services Inc (LSI), whose LED fixtures have been installed in the Brooker Gallery at the Field Museum in Chicago and the San Francisco Museum of Modern Art--applications where the CRI of LED lighting had previously not been considered adequate and the color variability too great. "It's a huge hit in museums," DeRoos said of their products.
For more information:
San Jose, California
Lighting Services Inc (LSI)
Stony Point, New York