发明名称 |
Autofocusing control system |
摘要 |
An autofocusing control system makes a position of focusing spot follow for itself a displacement of an information medium. In the autofocusing control system, a single mode semiconductor laser is excited in a multi oscillation mode by returning part of a reflected light beam from the information medium, and a focusing lens having chromatic aberration is used which focuses a laser beam from the semiconductor laser onto a different position along the optical axis of the lens in association with a different laser wavelength.
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申请公布号 |
US4725721(A) |
申请公布日期 |
1988.02.16 |
申请号 |
US19850766271 |
申请日期 |
1985.08.16 |
申请人 |
HITACHI, LTD. |
发明人 |
NAKAMURA, SHIGERU;TSUNODA, YOSHITO;MAEDA, TAKESHI |
分类号 |
G02B7/28;G11B7/085;G11B7/09;G11B7/135;(IPC1-7):G11B7/09 |
主分类号 |
G02B7/28 |
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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