Improvement of emission uniformity by using micro-cone patterned PDMS film

Che Yu Liu, Kuo Ju Chen, Da Wei Lin, Chia Yu Lee, Chien-Chung Lin*, Shih Hsuan Chien, Min Hsiung Shih, Gou Chung Chi, Chun-Yen Chang, Hao-Chung Kuo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Micro-patterned PDMS film was fabricated and combined with LED chip on board (COB) package to improve the emission uniformity of LED chip. The micro scale patterned sapphire substrate (PSS) was used as a mold to fabricate micro-cone patterned PDMS (MC-PDMS) film. A strong scattering effect from this MC-PDMS film can be verified by the high haze ratio and the Bi-directional Transmission effect. The angle dependent color temperature measurement system was used to measure the ?CCT of COB with and without MC-PDMS. The measurement results indicate that the ΔCCT was reduced from 1025K to 428K. This improvement can effectively eliminate the yellow ring effect of LED chip. This technology can be thus considered as a cost-effective way for the next generation of light source packages.

Original languageEnglish
Pages (from-to)4516-4522
Number of pages7
JournalOptics Express
Issue number4
StatePublished - 24 Feb 2014

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