Large-area, uniform white light LED source on a flexible substrate

Chin Wei Sher, Kuo Ju Chen, Chien-Chung Lin, Hau Vei Han, Huang Yu Lin, Zong Yi Tu, Hsien Hao Tu, Keiji Honjo, Hsin Yi Jiang, Sin Liang Ou, Ray-Hua Horng, Xiuling Li, Chien Chung Fu, Hao-Chung Kuo

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


This study demonstrates the flexible white LED structure with high lumen efficiency and uniform optical performance for neutral white and warm white CCT. Flip-chip LEDs were attached on a polyimide substrate with copper strips as electrical and thermal conduction paths. Yellow phosphors are mixed with polydimenthysiloxane (PDMS) to provide mechanical support and flexibility. The light efficiency of this device can reach 120 lm/W and 85% of light output uniformity of the emission area can be achieved. Moreover, the optical simulation is employed to evaluate various designs of this flexible film in order to obtain uniform output. Both the pitch between the individual devices and the thickness of the phosphor film are calculated for optimization purpose. This flexible white LED with high lumen efficiency and good reliability is suitable for the large area fixture in the general lighting applications.

Original languageEnglish
Pages (from-to)A1167-A1178
Number of pages12
JournalOptics Express
Issue number19
StatePublished - 1 Jan 2015


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