发明授权
- 专利标题: Bifocal optical pickup head
- 专利标题(中): 双焦光学拾音头
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申请号: US09262962申请日: 1999-03-04
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公开(公告)号: US06236633B1公开(公告)日: 2001-05-22
- 发明人: Hung-Lu Chang , Tzu-Ping Yang , Der-Ray Huang
- 申请人: Hung-Lu Chang , Tzu-Ping Yang , Der-Ray Huang
- 主分类号: G11B700
- IPC分类号: G11B700
摘要:
A bifocal optical pickup head is disclosed for use in a optical pickup apparatus having a single objective lens, for generating two different focuses (bifocus) to access a compact disc (CD) and a digital versatile disc (DVD), which the thickness is different. When a beam passes through an optical element disclosed in the present invention, numerical aperture is controlled and spherical aberration is reduced by the optical element due to variations in optical path and radius. Therefore, after beams having different numerical apertures are focused by an objective lens, various focuses can be obtained.
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