发明名称 |
Optical system, position detecting apparatus, magnetic recording apparatus, and lens with aperture |
摘要 |
For example, because an optical position detector for positioning a head for a high-density floppy disk is constituted so that openings 111 and 112 are used in which the thickness of a returning optical path bound for photodetectors 108R and 108L from a disk 107 is larger than the thickness of an advancing optical path bound for the disk 107 from a light source 101, a light beam is not easily interrupted in the middle of an optical path even if a light beam falls due to a tilt of the disk and therefore, it is possible to stably obtain position detection signals. Moreover, by reducing the luminous energy to be returned to a light source, it is possible to obtain a signal having less noises even if the distance between object images decreases and downsize an apparatus.In the case of a conventional optical position detector for positioning a head for a high-density floppy disk, a light beam is tilted due to a tilt of a disk and interrupted in its returning path because the numerical aperture of an optical system is small and the quality of a signal used for position detection is easily deteriorated. Moreover, when decreasing the distance between object images in order to downsize an apparatus, noises of a light source increase and the quality of a signal is deteriorated.
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申请公布号 |
US6327110(B1) |
申请公布日期 |
2001.12.04 |
申请号 |
US19980045149 |
申请日期 |
1998.03.19 |
申请人 |
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. |
发明人 |
SANO KOUSEI;KADOWAKI SHIN-ICHI |
分类号 |
G11B5/596;G11B7/09;(IPC1-7):G11B7/00 |
主分类号 |
G11B5/596 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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