发明名称 |
FOCUSING ERROR DETECTING SYSTEM FOR OPTICAL HEAD |
摘要 |
In a focusing error detecting method for an optical head wherein a laser beam from a laser light source is applied to a magneto-optical recording medium to form an image as a light spot thereon, and a focusing error is detecting according to a reflected light from the magneto-optical recording medium, the focusing error detecting method includes a step of dividing the reflected light from the magneto-optical recording medium into a 0-th order light, a +1-st order light and a -1-st order light by a diffraction grating, a step of applying the +1-st order light and the -1-st order light to a first detector and a second detector, respectively, the first and second detectors being arranged before and behind a beam emitting position of the laser light source, respectively and a step of computing outputs from the first and second detectors to obtain a focusing error signal. It is preferably that the laser light source is a semiconductor laser, and that the first and second detectors are mounted on a chip of the semiconductor laser to form a hybrid construction, thereby making the optical head more compact.
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申请公布号 |
US5095472(A) |
申请公布日期 |
1992.03.10 |
申请号 |
US19900531962 |
申请日期 |
1990.06.01 |
申请人 |
HITACHI CABLE LIMITED;HITACHI, LTD. |
发明人 |
UCHINO, AKIHIRO;NAITOH, SEIGO;OUCHI, HIROBUMI;NAKAMURA, SHIGERU |
分类号 |
G11B11/10;G11B7/09;G11B7/13;G11B7/135;G11B11/105 |
主分类号 |
G11B11/10 |
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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