发明名称 |
Optical head device, optical information device, and diffractive element |
摘要 |
An optical head device includes a diffraction grating which diffracts a part of the light beam which is selectively emitted from a semiconductor laser having two luminous points and is divided along a tangential direction of the track of the optical disk, a relationship of arrangement of the second and third regions corresponds to a relationship of the optical axes of the first and second light beams on the diffraction grating, the second region is located at a position crossing an optical axis of the first light beam, a phase difference between phases of the first and third regions is 180°, a phase difference between phases of the third and fourth regions is 180°, and the third region has a width which is not larger than amount of a position deviation of ±first-order diffracted light of the second light beam from zeroth-order diffracted light. |
申请公布号 |
US8259554(B2) |
申请公布日期 |
2012.09.04 |
申请号 |
US20080680917 |
申请日期 |
2008.10.01 |
申请人 |
SANO KOUSEI;UENO HIROTAKA;PANASONIC CORPORATION |
发明人 |
SANO KOUSEI;UENO HIROTAKA |
分类号 |
G11B7/00;G11B7/125;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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