Potential of low-temperature post processing of silica gel for high-temperature stable LED encapsulant

In this study, a low-temperature post processing of silica gel for high-temperature stable LED encapsulant was developed. The results indicated that the silica gels prepared by 1st post heat treatment at 300 °C for 5 h and then 2nd post processing at 80 °C for 50 h can have similar low weight loss and high transmittance as the silica gels were processed at 800 °C for 5 h. The result of such low processing temperature implies it may be possible to encapsulate inorganic gel on LED as the convenient potting method is being used in silicone encapsulation technology. However, the processing time can be greatly reduced if vacuum oven is used. Further surface impermeability improvement is also possible by additional local surface heat treatment. The advantages of adopting silica encapsulant in LED modules include higher thermal stability and better optical performance consistency in lumen, color temperature, etc. in new applications.