Enhancing Optical Performance of Chip-Scale Packaged White LEDs by Phosphor-in-Glass With High-Reflective Dam

Abstract

In this work, the optical performance of chip-scale packaged (CSP) white light-emitting diodes (LEDs) was enhanced by a phosphor-in-glass (PiG) converter with a high-reflective dam. The high-reflective dam consisted of boron nitride (BN)/silicone composite fabricated at the side wall of the LED chip and PiG converter to obtain the PiG-BN-CSP LED. The optical performance of PiG-BN-CSP LED was optimized by adjusting the concentration of BN particles. When the BN concentration is 7.5 wt%, the PiG-7.5BN-CSP LED achieves an appropriate natural white light. The related luminous efficiency (LE), correlated color temperature (CCT), and chromaticity coordinate are 104.7 lm/W, 5714 K, and (0.3273, 0.3563), respectively. The beam angle of PiG-BN-CSP LED is effectively controlled by adjusting the BN concentration. The beam angle of 118.5° is achieved at the BN concentration of 7.5 wt%. The maximum temperature of PiG-7.5BN-CSP LED is 92.7 °C when the input current is 1200 mA. Furthermore, the PiG-up BN-CSP achieves better optical performance compared with the PiG-up-CSP. The results show that the PiG with a high-reflective dam is an efficient CSP structure for high-power-density white LEDs.