Research labs generally use high-pressure mercury or xenon light sources for fluorescence microscopy. These lamps are bright and produce ample light for most work, and, as a result, have been widely used in research for several years. But the increased brightness afforded by these light sources is accompanied by several negative aspects. Mercury-containing light sources present a personal safety hazard and an environmental hazard. In addition, the cost of ownership of these light sources is high, and they often no longer meet the experimental needs of many modern laboratories.