Using SiO 2 nano-particles for better color uniformity and lumen output in 8500 K conformal and in-cup white LEDs

Abstract

In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO 2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO 2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO 2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO 2 -doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO 2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO 2 -doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO 2. These experimental outcomes suggest that SiO 2 is an effective material to add in WLEDs structure for better lighting efficiency.