Next-generation high-reliability laser light engine by glass phosphor-converted layer (Conference Presentation)

A new scheme of high-reliability laser light engine (LLE) employing a novel glass-based phosphor-converted layer is proposed and demonstrated. The LLE module consists of a high-power blue light laser array and a color wheel, which includes two glass-based phosphor-converted layers of yellow Ce:YAG and green Ce:LuAG and a micro motor. The combinations of blue, yellow, and green lights produce high-purity phosphor-converted white-laser-diodes (PC-WLDs). The lumen degradation and chromaticity shift in the glass-based phosphor-converted layer under different laser powers are presented and compared with those of silicon-based PC-WLDs. The results showed that the glass based PC-WLDs exhibited in lower lumen loss and less chromaticity shifts than the silicon-based PC-WLDs. The long term reliability study evaluation in glass- and silicone-based PC-WLDs under high-power 120 W at room temperature for 20,000 hours is also presented and compared. The result showed that the silicone-based PC-WLDs exhibited 50% in lumen decay which failed in operation, while the glass-based PC-WLDs only exhibited 2% in lumen decay. This indicates that the proposed LLE modules are benefit to employ in the area where the silicone-based material fails to stand for long and strict reliability is highly required. This study demonstrates the advantages of adapting novel glass as a phosphor-converted color wheel in the LLE modules that provide unique high-reliability as well as better performance for use in the next-generation laser projector system.