Light Extraction Enhancement of Deep Ultraviolet Light-Emitting Diodes by Using Aluminum Reflector Cup

In this paper, we proposed an optimized aluminum (Al) reflector for the light extraction efficiency enhancement of deep UV-LEDs. The optical model of deep UV-LEDs was established and the optical simulations were performed to achieve the optimized reflector. The deep UV-LEDs yield a highest light efficiency when the reflector has optimized feature sizes, which are an angle of 60°, a height of 2.0 mm, and an internal radius of 2.5 mm. Furthermore, the optimized Al reflector were designed and fabricated and applied to deep UV-LEDs package. Therefore, the optical light output powers of deep UV-LEDs are improved by 25.5%, 43.8%, and 39.3%, respectively, by using the optimized reflectors at the different driving current of 50mA, 100mA, 150mA. This is due to the remarkable deep UV-LEDs optical reflection effect of the Al reflector, which increases the light extraction of the sidewall emission of the deep UV-LED chip.