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Proceedings Paper

Individual information beam broadcasting system using a PAL-SLM based CGH beam former for the location based information services
Author(s): Shunichi Osawa; Hideo Itoh; Yoshiyuki Nakamura; Takuichi Nishimura; Xin Lin; Masamitsu Tokuda
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Paper Abstract

As an implementation of ubiquitous information service environments, we have been researching location-based information service systems at indoor and short distance area. The system should provide adequate information services, which fit the user's attributes, such as language, knowledge level and the volume of information, what is so-called "Right now, Here, and for Me" information services. Keeping privacy and security of the user is an important issue. Spatial optical communication technique is used for the system because the technique is easy to implement a location- and direction-based communication system. Information broadcasting in an area can be realized by an omnidirectional modulated light emission. However, the omnidirectional beam causes spill out of secure information to others, and has lower energy conservation than a focused beam communication. In this paper, a new spatial optical information broadcasting system, which can focus modulated beams only to intended users. CGH (Computer Generated Hologram) technique on a SLM (Spatial Light Modulator) is proposed and demonstrated. The system is composed of a PAL-SLM (Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator), an eye-safe semiconductor laser or a semiconductor laser pumped YAG laser for the beam emitter, and an infrared video camera with an infrared LED illuminator for user locator. Experimental results of beam deflecting characteristics are described on beam uniformity, deflecting angle and the enhancement, communication characteristics, and real time tracking of user with a corner-reflecting sheet.

Paper Details

Date Published: 20 January 2006
PDF: 8 pages
Proc. SPIE 6027, ICO20: Optical Information Processing, 60270W (20 January 2006); doi: 10.1117/12.667921
Show Author Affiliations
Shunichi Osawa, Musashi Institute of Technology (Japan)
Hideo Itoh, Advanced Research Institute of Science and Technology and CREST (Japan)
Yoshiyuki Nakamura, Advanced Research Institute of Science and Technology and CREST (Japan)
Takuichi Nishimura, Advanced Research Institute of Science and Technology and CREST (Japan)
Xin Lin, Advanced Research Institute of Science and Technology and CREST (Japan)
Masamitsu Tokuda, Musashi Institute of Technology (Japan)


Published in SPIE Proceedings Vol. 6027:
ICO20: Optical Information Processing
Yunlong Sheng; Songlin Zhuang; Yimo Zhang, Editor(s)

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