LED芯片表面制备荧光粉层的新方法

New method to form phosphor layer on the surface of LED chip

基于水溶性感光胶制得白光LED荧光粉粉层,研究了以有机胶体(PVA)为外相,以憎水性粘合剂(硅胶)为内相的感光胶特性,探讨了荧光粉粉层结构的性能及其对器件光通量的影响,结果显示:表面活性剂的加入,增加了粉浆的稳定性;感光胶内外相结构既保持了硅胶的优良特性,又能通过外相曝光显影使硅胶具有平面保形涂层。得到的白光LED的光通量大幅度提高,比原粉浆法得到的器件的光通量高15.5%～17.5%,白光输出稳定,在连续点亮840h后,光通量基本没有变化。

Phosphor layer was formed on white LEDs chip based on water-soluble emulsion. The characteristics of the emulsion, in which PVA gel acts as external phase and hydrophobic silica gel acts as internal phase, was investigated. The performance of phosphor layer and its effect on the luminous flux of LEDs was studied. The results indicate that the surfactant incorporation enhances the stability of slurry containing emulsion and phosphor; The unique structure of emulsion, which consists of internal and external phase, not only keeps the good characteristics of silica gel but also induce a flat phosphor layer containing silica gel through the developing of external phase. Compared to the white LEDs with phosphor layer prepared using original slurry method, the luminous flux of white LEDs with phosphor layer prepared using new method is remarkably enhanced by 15.5%- 17.5%; The new white LEDs exhibit a stable light power and its luminous flux doesn＇t show any change after the LEDs working for 840 h continuously.