| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device capable of accurately detecting a spherical aberration generated in a condensing optical system with respect to each standard, properly correcting the aberration, and properly recording/reproducing information in an optical disk in a compatible head equipped with objective lenses of different incident pupils corresponding to a plurality of standards. <P>SOLUTION: The optical head device corresponding to a plurality of standards includes a plurality of areas disposed in a diffracted light optical elements to diffract lights in different directions depending on wavelengths, first to third photodetectors for receiving the diffracted lights, and a control signal generation circuit for generating a control signal to drive a beam expander lens based on the detecting results of the photodetectors. <P>COPYRIGHT: (C)2007,JPO&INPIT |
