12 March 2012 Optical design of single plano-convex freeform lens-based illumination system for color filter liquid crystal on silicon pico projectors
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Optical Engineering, 51(3), 033002 (2012). doi:10.1117/1.OE.51.3.033002
Abstract
An efficient and practical method for the design of an illumination system with a single plano-convex freeform lens for color filter liquid crystal on silicon (CF-LCoS) pico projectors is proposed. Based on Snell's law and the energy conservation law, the initial illumination system is derived and the freeform lens is numerically calculated from a first-order partial differential equation, which could be considered a good optimization start for further optimization. For an actual extended LED chip, a local optimization algorithm could efficiently achieve the design goals based on the specifically designed initial system. The design example shows that the illumination system employed a CF-LCOS panel with a diagonal of 0.38-in and an aspect ratio of 16∶9 meets the needs of the optical engine for a pico projector, which has a transmission efficiency of 50% and an ANSI nine-point uniformity over 95%, with the whole optical engine volume 28.4×18.5×8  mm3. Moreover, analysis indicates that the design method could obtain outstanding performance with compactness and low cost.
© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)
Enguo Chen, Peng Liu, Feihong Yu, "Optical design of single plano-convex freeform lens-based illumination system for color filter liquid crystal on silicon pico projectors," Optical Engineering 51(3), 033002 (12 March 2012). https://doi.org/10.1117/1.OE.51.3.033002
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KEYWORDS
Liquid crystal on silicon

Light emitting diodes

Optimization (mathematics)

Optical design

Pico projectors

Illumination engineering

Optical filters

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