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Proceedings Paper

A novel integrated catadioptric pick-up with ferrofluid cooling structure
Author(s): Kazuhiko Yamanaka; Takuya Okuda; Tomoaki Tojo; Shinichi Ijima; Kazutoshi Onozawa; Daisuke Ueda; Junichi Kubo; Seiichiro Kitagawa
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Paper Abstract

We proposed the integrated optical pick-up with a catadioptric system which has a super resolution effect and with ferrofluid cooling structure. All of optical elements such as an objective lens, a laser diode and a photodetector are integrated into the moving part of the actuator to miniaturize the pick-up. Laser beam is double reflected between first reflecting region on top of the objective lens and second reflecting region on a reflecting mirror placed under the objective lens to miniaturize the optical system. The moving part having the laser diode and the photodetector needs high cooling performance to realize the optical system. We developed the cooling structure with ferrofluid held between a magnet and a coil of the actuator. Ferrofluid works as a cooling path to conduct the heat in the moving part towards external parts. We achieved the results as described below. Temperature of the laser diode is approximately equivalent to conventional pick-up against the heat of about 200mW generated in the moving part. Thermal resistance of 120 degree/Watt is available for practical use. The cooling structure leads the results of optical characteristics. As a super resolution effect, spot size of the integrated optical pick-up with wavelength of 660nm and a numerical aperture (NA) of 0.55 is equivalent to spot size of conventional pick-ups with wavelength of 660nm and a NA of 0.65. Focal and tracking error signals for servo control are available for practical use. The cooling performance is enough for realizing the integrated optical pick-up.

Paper Details

Date Published: 17 June 2004
PDF: 9 pages
Proc. SPIE 5362, Advanced Optical and Quantum Memories and Computing, (17 June 2004); doi: 10.1117/12.527941
Show Author Affiliations
Kazuhiko Yamanaka, Matsushita Electric Industrial Co., Ltd. (Japan)
Takuya Okuda, Matsushita Electric Industrial Co., Ltd. (Japan)
Tomoaki Tojo, Matsushita Electric Industrial Co., Ltd. (Japan)
Shinichi Ijima, Matsushita Electric Industrial Co., Ltd. (Japan)
Kazutoshi Onozawa, Matsushita Electric Industrial Co., Ltd. (Japan)
Daisuke Ueda, Matsushita Electric Industrial Co., Ltd. (Japan)
Junichi Kubo, NALUX Co., Ltd. (Japan)
Seiichiro Kitagawa, NALUX Co., Ltd. (Japan)


Published in SPIE Proceedings Vol. 5362:
Advanced Optical and Quantum Memories and Computing
Hans J. Coufal; Zameer U. Hasan, Editor(s)

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