Potential brightness of class 3R hybrid laser-phosphor projectors

A new class of hybrid laser-phosphor projectors uses multiple blue direct-diode lasers to create blue light and to stimulate phosphors that emit red and green light. Generated via fluorescence, the red and green light from the phosphors lacks the properties associated with laser light (e.g., monochromatic, coherent, low etendue, etc.) and therefore should not be treated as laser light when determining the laser-safety rating of these projectors. Considering only the blue laser light, the maximum lumen output for a Class-3R laser-phosphor projector is calculated. In addition, the dependence of laser-safety classification on key projector parameters, including apparent source size, lens throw ratio, and microdisplay-panel size, is investigated.