发明名称 |
Optical disk apparatus compatible with different types of mediums |
摘要 |
A polarizing beam splitter for separating an upstream beam from a downstream beam according to the polarization of an incident beam is provided between first and second light sources emitting laser beams at respective wavelength and an objective lens. A phase plate for providing a phase difference to a beam incident on the polarizing beam splitter is provided between the polarizing beam splitter and the light sources. A portion of the laser beam incident on the polarizing beam splitter is reflected by the polarizing beam splitter and caused to be incident on a photo-detecting unit, so as to prevent an unnecessary portion of the laser beam is incident on the photo-detecting unit. According to the invention, the laser beam is used efficiently and the cost of fabricating an optical disk apparatus is reduced by eliminating a need for a gain controlling circuit in the photo-detecting unit.
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申请公布号 |
US2001050892(A1) |
申请公布日期 |
2001.12.13 |
申请号 |
US20010760743 |
申请日期 |
2001.01.17 |
申请人 |
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发明人 |
TAKAHASHI YOSHITAKA;AKIYAMA HIROSHI |
分类号 |
G11B7/00;G11B7/12;G11B7/125;G11B7/135;(IPC1-7):G11B7/135 |
主分类号 |
G11B7/00 |
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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