Transparent Bamboo as an Optical Management Material to Improve Color Uniformity of Light-Emitting Diodes

We propose an effective strategy for improving the color uniformity of phosphor-coated LEDs (pc-LEDs) by employing transparent bamboo (TB) as an optical management material. The "yellow ring effects" existing in pc-LEDs cannot be ignored, and it is significant to alleviate this effect by introducing some strategies. The TB made by lignin modification treatment and polymer impregnation is used in this work. The spatial distribution of correlated color temperature (CCT) and color coordinates of pc-LEDs covered by TB are examined. Results have shown that both distribution consistency of CCT and color coordinates are improved to some extent. Finally, the size-dependent characteristics of studied samples are also investigated, and the size length of TB of 1.0 cm is the best solution among our studied sizes. This work would pave an effective way for improving the color uniformity of pc-LEDs by using the TB as an optical management.