| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize an optical disk apparatus in which when a DVD-RAM disk or the like are reproduced, influence of disturbance caused when a focus deviation signal is detected by an astigmatic system is reduced remarkably, and influence of offset due to objective lens displacement caused when a tracking error signal is detected by a push-pull system is reduced remarkably, further which can cope with reproduction of existing optical disks such as CD, CD-ROM, CD-R as well as high density disks such as DVD-RAM, DVD-ROM disks using a simple optical head, and which has high versatility. <P>SOLUTION: By irradiating the prescribed position of an optical disk with three light beams separated by diffraction gratings and providing an optical detector having the prescribed constitution and divided into twelve, such the highly versatile optical disk apparatus can be obtained by which a good focus deviation signal and a tracking error signal are obtained while a signal can be reproduced for a plurality of optical disks having different recording density and disk constitution using a simple optical head. <P>COPYRIGHT: (C)2007,JPO&INPIT |
