Laser-Excited Phosphor/Dye in Liquid for High-Power Digital Projectors
Ken Li, President & CEO
Dr. Li served as President and CEO at Wavien, Inc. Dr. Li holds a BSEE from California Institute of Technology. He completed his MSEE and PhD in quantum electronics from Northwestern University and University of California, Berkeley respectively. He also completed his EMBA in University of California, Los Angeles. Prior to joining Wavien, Dr. Li held various senior positions in TRW Technology Research Center, PCO, Inc. (Joint venture of Corning and IBM), and Hewlett Packard, responsible for the development and manufacturing of lasers, LEDs, and photodetectors for fiber optic communication. Dr. Li has published over 50 papers in technical journals and presented at many conferences. Dr. Li is the original inventor and developer of the Dual Paraboloid Reflector (DPR) and Recycling LED Technology (RLT™), and more than 70 issued patents with many more pending in the area of illumination system using arc lamps and LEDs.
Laser excited phosphor has been used to excite phosphor material, producing a light source with high brightness light outputs and with long lifetime. Due to the difficulty of heat dissipation and aging of the phosphor in using standard phosphor wheel configuration, the output of such projectors are limited to upper limit in the range of 6,000 lumens to 12,000 lumens. This paper describes the used of circulating liquid with a suspension of phosphor powder in an optical cell. When the phosphor particles in liquid are excited by the laser, a visible light with certain bandwidth is generated. Since each phosphor particle is surrounded by liquid, the heat sinking issues are eliminated. To provide high illumination efficiency, multiple types of phosphor can be used with different center wavelengths such that the proper output spectrum can be obtain. To add further flexibility, dye can be used in addition to phosphor providing the desired output light spectrum. Using this technology, projector output can be extended to beyond 30,000 lumens for standard digital cinema and beyond 60,000 lumens for 3D digital cinema.