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Proceedings Paper

Uniform light distribution by using microlenses with various focal lengths
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Paper Abstract

The increasing demands for non-self-emissive portable display devices jointly stimulate the needs for additional front light units to provide extra illumination to compensate for the ambient light in dim environment. The advantages of light emitting diodes (LED), such as high efficiency and small size, make it an ideal source for the compact unit, but direct LED lighting is impractical. Secondary optics is commonly adopted in illumination occasions to ensure the output from the LED dies meet the overall specification. Considering an oblique incidence situation, light mapping redistribution is inevitable. In this paper, we propose a beam shaping method adopting microlens array with various focal length to achieve uniform light distribution. The design is based on edge ray principle, which considers each microlens individually. Microlenses with various focuses were made by photoresist thermal reflow process to verify the novel design.

Paper Details

Date Published: 21 September 2011
PDF: 9 pages
Proc. SPIE 8124, Nonimaging Optics: Efficient Design for Illumination and Solar Concentration VIII, 812405 (21 September 2011); doi: 10.1117/12.893499
Show Author Affiliations
I-Chiao Hsu, National Taiwan Univ. (Taiwan)
Guo-Dung John Su, National Taiwan Univ. (Taiwan)

Published in SPIE Proceedings Vol. 8124:
Nonimaging Optics: Efficient Design for Illumination and Solar Concentration VIII
Roland Winston; Jeffrey M. Gordon, Editor(s)

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