Applying SiO2 nano-particles for improving optical properties of WLED conformal and in-cup structures

Abstract

This article is the analysis of SiO₂ nano-particles’ influences on the luminous efficiency and the color temperature uniformity of a remote phosphor structure in a WLED. The purpose of integrating SiO₂ into the silicone layer in the remote phosphor structure is to significantly promote the scattering occurrences. Particularly, with an appropriate proportion of SiO₂, there could be more blue lights generated at large angles, leading to reducing the angular-dependent color temperature deviation. The luminous flux also can get benefits from SiO₂ addition owing to a proper air-phosphor layer refractive index ratio provided by this SiO₂/silicone compound. The attained experimental results were compared with optical values of a non-SiO₂ remote phosphor configuration and showed a notable enhancement. The color deviation was reduced by approximately 600 K in the angles from -70^{0 ­}to 70⁰. Additionally, the lumen efficiency was improved by 2.25% at 120 mA driving current. Hence, SiO₂ can be used to boost both color uniformity and luminous efficacy for remote-phosphor WLED.