| Optical head and information recording apparatus | |
| NAKAMURA, SHIGERU; ARIMOTO, AKIRA; NAKAO, TAKESHI; UMEDA, MARIKO | |
| 1994-11-01 | |
| 著作权人 | HITACHI, LTD., A CORPORATION OF JAPAN |
| 专利号 | US5361244 |
| 国家 | 美国 |
| 文献子类 | 授权发明 |
| 其他题名 | Optical head and information recording apparatus |
| 英文摘要 | Disclosed herein is a compact, adjustment-free, unitary optical head wherein diffraction grating made of a birefrigence material and having convexities and concavities of grating grooves so set that the difference of their optical path lengths is some multiples and a half of the wavelength for an ordinary beam and an extraordinary beam, a diffraction grating providing astigmatisms to +/-1 order beams, a quarter wavelength plate, and other optical components, are interposed between a semiconductor laser and a focussing lens and are stored inside an optical head body filled with a dry nitrogen gas. A focus error detection signal is obtained from the difference of the degrees of modulation of the +/-1 order reflected beams by pre-wobbled pits, and adjustment of the optical beam can be carried out by driving the body by a two-directional head actuator. |
| 公开日期 | 1994-11-01 |
| 申请日期 | 1992-04-08 |
| 状态 | 失效 |
| 内容类型 | 专利 |
| 源URL | [http://ir.opt.ac.cn/handle/181661/33401]  |
| 专题 | 半导体激光器专利数据库 |
| 作者单位 | HITACHI, LTD., A CORPORATION OF JAPAN |
| 推荐引用方式 GB/T 7714 | NAKAMURA, SHIGERU,ARIMOTO, AKIRA,NAKAO, TAKESHI,et al. Optical head and information recording apparatus. US5361244. 1994-11-01. |
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