Comparison of silicone and spin-on glass packaging materials for light-emitting diode encapsulation

• Spin-on-glass (SOG) material was used to replace silicone coating for LED packaging.
• Initial brightness of SOG packaging is lower than that of silicone packaging.
• Over time, light attenuation in SOG is much lower than that in silicone.
• Color rendering index and brightness of LED packaging was optimized by Taguchi method.

Traditional white light light-emitting diode (LED) encapsulation is performed by mixed phosphors and silicone coating on LED die. However, this encapsulation with silicone coating incurs overheated temperatures and yellowing problem. Therefore, this work attempts to replace silicone paste by using spin-on-glass (SOG) materials. Experimental results indicate that although initial brightness of SOG-based packaging is lower than that of silicone packaging, its light attenuation is significantly lower than that of silicone for a long lighting time. After the LED power is turned on for 12 h, the brightness of LED with silicone and SOG material packaging decreases from 84 to 48 lm and 73 to 59 lm, respectively. Therefore, SOG material provides an alternative packaging solution for high power LED lighting applications.