发明授权
- 专利标题： Magneto-optical disc system having an objective lens with a numerical aperture related to the thickness of the protective layer
- 专利标题（中）： 具有具有与保护层的厚度相关的数值孔径的物镜的磁光盘系统
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申请号： US499347申请日： 1995-07-07
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公开(公告)号： US5617378A公开(公告)日： 1997-04-01
- 发明人: Tetsu Watanabe , Yoshio Aoki
- 申请人： Tetsu Watanabe , Yoshio Aoki
- 申请人地址： JPX Tokyo
- 专利权人： Sony Corporation
- 当前专利权人： Sony Corporation
- 当前专利权人地址： JPX Tokyo
- 优先权： JPX2-21210 19900131
- 主分类号： G11B7/007
- IPC分类号： G11B7/007 ; G11B7/135 ; G11B7/24 ; G11B11/105 ; G11B11/00
摘要：
An magneto-optical disc system includes an magneto-optical disc with a light-transmitting cover and an objective lens for bundling or focusing a laser beam on a recording layer of the magneto-optical disc in order to perform recording and/or reproduction. The thickness t.sub.2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70 and the wavelength of the light beam is selected to be between 635 and 680 nanometers.
公开/授权文献
- US4496930A In-line fire detector of a fire protection and alarm system 公开/授权日：1985-01-29
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