High lumen density of Al2O3-LuAG: Ce composite ceramic for high-brightness display

Thermally robust and highly efficient green-emitting luminescent ceramics are gradually attracting great attention as promising phosphors using in high-brightness laser phosphor display to reduce serious speckle noise as well as high cost. However, lumen density is still seriously restricting their potential applications especially under high-power density laser due to insufficient absorption of blue laser and significant thermal quenching. Here, we report an Al 2 O 3 -LuAG: Ce composite ceramic phosphor (CCP) for high-brightness laser phosphor display. Owing to good optical properties and high thermal conductivity of Al 2 O 3 , the Al 2 O 3 -LuAG: Ce CCP shows high photoluminescence quantum yield (79.6%), low thermal quenching (only 3.2% loss in luminescence at 200°C), and high thermal conductivity (18.9 W·m −1 ·K −1 ). Moreover, the Al 2 O 3 , as scattering centers, enhances the Rayleigh–Mie scattering of the blue laser, and hence the absorption of the Al 2 O 3 -LuAG: Ce CCP exhibits a remarkable improvement (~2.3 times) at 450 nm. Finally, with optimized thickness (0.3 mm) of Al 2 O 3 -LuAG: Ce CCP, an excellent luminous efficiency (216 lm·W −1 ) and outstanding lumen density (6129 lm·mm −2 ) of the green-emitting light source was obtained by driving under a high-power density (28.33 W·mm −2 ) blue laser. All of those validate the suitability of the Al 2 O 3 -LuAG: Ce CCP for high-brightness display.