Using SiO2 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 SiO₂ 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 SiO₂ particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO₂ that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO₂-doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO₂ with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO₂-doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO₂. These experimental outcomes suggest that SiO₂ is an effective material to add in WLEDs structure for better lighting efficiency.