发明名称 |
Optical head device and diffractive element, optical information apparatus, computer, disc player, car navigation system, optical disc recorder, and vehicle |
摘要 |
In an optical head device responding to optical disc of different track pitches, an effect of both obtaining the tracking error signal by the optimum DPP method using a single diffractive element and suppressing the lowering amount in the amplitude of the tracking error signal in a state the object lens is moved by track following is obtained. In the optical head device, the grating phase of left and right regions of a sub-beam generating diffractive element differ from each other by 180 degrees. A central region of the sub-beam generating diffractive element has a grating pattern different from the left and right regions, and is divided into a plurality of regions to form different gratings different from each other.
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申请公布号 |
US7801009(B2) |
申请公布日期 |
2010.09.21 |
申请号 |
US20070892464 |
申请日期 |
2007.08.23 |
申请人 |
PANASONIC CORPORATION |
发明人 |
KOMMA YOSHIAKI |
分类号 |
G11B7/00;G11B7/13;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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