Preparation of phosphor glass via screen printing technology and packaged performance for LEDs

Abstract

A simple and practical method for preparing phosphor glass is proposed. Phosphor distribution and element analysis are investigated by optical microscope and FE-SEM. The phosphor particles dispersed in matrix is vividly observed and their distributions are uniform. Spectrum distribution and color coordinates depended on thickness of screen printed phosphor layer coupled with blue LED chip are also studied. The luminous efficacy of the 75 μ m phosphor layer phosphor glass packaged white LED is 81.24 lm/W at 350mA. This study opens up many possibilities for applications using the phosphor glass on a selected chip which emission is well absorbed by all phosphors. The screen printing technique also offers possibilities for the design and engineering of complex phosphor layers on glass substrates. This design allowed us to get rid of the re-absorption problems affecting the global chromaticity. Phosphor screen printing tecnnology allows the realization of high stability and thermal conductivity for phosphor layer. And this simple phosphor glass method provides many possibilities for LED packing, including TFFC (thin film flip chip) and remote phosphor technology.