| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical system in which such the problem is solved that in an optical head performing recording/reproduction of a plurality of optical disks by one objective lens, since there is a problem of chromatic aberration of a detection system and optical path branch of three wavelengths, the optical system becomes complicated and an inexpensive optical head cannot be constituted, and to provide the optical head using it, and a device and a system applying these. <P>SOLUTION: In the optical head, since a collimate lens is used also as a converging lens for detection in the optical system using three wavelengths, positional deviation of detection spots caused by difference of wavelengths is corrected by the movement of the collimate lens, and a beam splitter for branching the optical paths of three wavelengths in diverging light is attained by two groups of optical multi-layer films of which the design wavelengths are different from each other. Thereby, the optical system is simplified. <P>COPYRIGHT: (C)2009,JPO&INPIT |
