The characteristics of white LEDs with curved remote phosphor layer

• Main Authors: Tu, Huang-Tsung, 凃皇總
• Other Authors: Ying, Shang-Ping
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/92338106137051542844

碩士 === 明新科技大學 === 電子工程研究所 === 102 === For the phosphor-converted LEDs (pcLEDs), the enhancement of the package efficiency is always an important issue. For the typical structures of the pcLEDs, a phosphor layer is close to the contour of the LED chip. Then a large portion of converted light from the phosphor would impinge on the LED chip and be absorbed by the LED chip. Therefore, the package efficiency of the pcLEDs will be low. To improve the package efficiency for pcLEDs, the remote phosphor structure with the phosphor layer placed at a sufficiently large distance from the LED chip was proposed. The remote phosphor structure lowers the probability of a light from the phosphor and directly hitting the absorptive LED chip, thereby improving the package efficiency. However, for the conventional remote phosphor structure with flat remote phosphor layer, there is still a large probability of a light being trapped in the flat remote phosphor layer owing to the total internal reflection on the interface between phosphor layer and air. Therefore, the efficiency of the pcLEDs with remote phosphor structure will be limited. In this paper, a new packaging structure of white LEDs that employs a curved remote phosphor layer for remote phosphor configuration is proposed. The pcLED with curved remote phosphor structure will promotea high package efficiency owing to the low total internal reflection on the interface between phosphor layer and air. The optical simulations were used to analysis the package efficiency and angular chromaticity of the curved remote phosphor structures with different curvatures. At the meantime, the pcLEDs with the some configurations were packaged and measured to conform the simulation results for the curved remote phosphor structures.