High Reliability and Luminance of Color Wheel by Novel Phosphor-in-Inorganic Silicone

A high reliability and luminance of color wheel in laser light engine (LLE) employing novel phosphor-in-inorganic silicone (PiIS) fabricated at low temperature of 180°C for laser projector applications is presented and demonstrated for the first time. Yellow (Y₃Al₅O₁₂:Ce³+) and green (Lu₃Al₅O₁₂:Ce³+) phosphors were uniformly mixed by inorganic silicone, organic silicone, and glass to fabricate as a phosphor color wheel. The PiIS based color wheels showed better thermal stability than the phosphor-in-organic silicone (PiOS) about 3-7 times less lumen loss and 7-8 times less chromaticity shift under accelerated aging at 350°C for 1008 hours. The advantage of the PiIS fabricated at a low temperature of 180oC enabled achievement of excellent thermal performance, which was similar to the phosphor-in-glass (PiG) fabricated at a high temperature of 680oC. The good thermal stability of the PiIS can be attributed to the high glass melting temperature up to 510oC. Low temperature fabrication, excellent optical performance, and high reliability of the proposed PiIS based color wheels benefit as promising candidates to replace the current PiOS or PIG based color wheels in the LLE modules for the next-generation laser projector applications.