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Proceedings Paper

Illumination by subwavelength grating with antireflection effect
Author(s): Shigeto Omori; Masato Okano; Hiroshi Toyota
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Paper Abstract

This research concerns a thin illumination device to be used by mounting between a Reflection-type liquid crystal display device (LCD) and a viewer. Because, the brightness of display is highly dependent on the surrounding environment, an auxiliary illumination is needed to provide against cases when surrounding light is insufficient. We investigated theoretically and experimentally into a grating for monochromatic illumination. First, the requirements of illumination were calculated and a grating shape for illumination was developed. The antireflection effect of the grating was confirmed. In this paper, the diffraction efficiency of the grating was calculated by a rigorous analysis method. It is structured the right triangular profile with the subwavelength period to project light onto the display object by using diffraction effect. Therefore, the light guide of length/thickness equals 50, with the grating, gets an illumination efficiency of 90%. Not occurring reflected light from the illumination device by an antireflection effect prevents that the contrast of display becomes low. Next, the fabrication method by using a reactive ion etching (RIE) that makes the grating of high precision was developed.

Paper Details

Date Published: 9 November 2001
PDF: 8 pages
Proc. SPIE 4440, Lithographic and Micromachining Techniques for Optical Component Fabrication, (9 November 2001); doi: 10.1117/12.448050
Show Author Affiliations
Shigeto Omori, Osaka Science and Technology Ctr. (Japan)
Masato Okano, Osaka Science and Technology Ctr. (Japan)
Hiroshi Toyota, Osaka Science and Technology Ctr. (Japan)

Published in SPIE Proceedings Vol. 4440:
Lithographic and Micromachining Techniques for Optical Component Fabrication
Ernst-Bernhard Kley; Hans Peter Herzig, Editor(s)

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