Thermal Management of Laser-driven Color Converter by Phosphor-in-glass Layer on Thermoelectric Cooler

Laser diode (LD) encapsulated with color converter is regarded as a promising high-luminescence white light source. Driven by high-power laser irradiation, thermal issues of phosphor converter cannot be ignored. In this paper, a thermoelectric cooler (TEC) based converter structure was proposed to improve the process dissipating heat from phosphor conversion. The TEC was coated with a layer of LSN:Ce phosphor-in-glass (PiG) paste on its cold-sided substrate and sintered into a PiG film. On account of the Peltier effect of TEC driven by input current, the heat originated from down-conversion under laser radiation was transmitted effectively to the air. Adjusting the laser excitation power from 0.74 to 4.82 W, the temperature of laser irradiation spot on the LSC:Ce-PiG layer only rises from -9.0 to 32.1°C, which is decreased by 77.9°C (~70.8%) under 4.82 W laser radiation. Moreover, driven by a 4.82 W blue LD, the PiG-on-TEC obtains a warm white light with a luminous flux of 767 lm (a luminous efficiency of 159.1 lm/W) and a correlated color temperature (CCT) of 4448 K. These results manifest that there is a potential value of the PiG-on-TEC structure in the applications of high-luminescence laser white light source.