近紫外芯片激发三基色荧光粉制作的白光LED

使用发射波长为395～400 nm的近紫外LED芯片来激发发射峰值波长分别在615,505和445 nm的红绿蓝三基色荧光粉,建立三基色荧光粉混光理论模型,制作不同色温下高显色指数白光发光二极管,研究其光电特性。实验结果表明,采用近紫外激发的三基色白光器件色温为3 000～9 000 K范围内,其显色指数均能保持在80～90之间;当色温大于5 000 K时,显色指数可以达到85;测试结果与理论计算吻合良好。最后,实验证明加入TiO2粉末可消除白光LED中残余近紫外线,三基色荧光粉白光LED色度参数受工作电流变化的影响较小。

White LED Based on Near UV LED Chip Precoated with Tri-Color Phosphors

The white light-emitting diodes(WLEDs)were fabricated by using near ultraviolet(n-UV,395-400 nm)LED chips to excite RGB(red/green/blue)phosphors,and the excitation peak wavelengths was around 615,505 and 445 nm separately.Research on the optical and electrical properties shows that with a wide range of correlated color temperature(TC)from 3 000 to 9 000 K,the color-rendering index(Ra)of such LEDs maintaine between 80-90,especially that when color temperature is close to or higher than 5 000 K,the color-rendering index can reach 85,which accord with the theoretical arithmetic.The effect of eliminating such LEDs’ residual UV by adding TiO2 powder is also preliminarily studied at the end of this experimentation.The color parameters are hardly influenced by the change of injection current,indicating that such white-light LEDs are optically stable.