| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device in which influence of stray light by needless focus can be suppressed by simple constitution, even when a plurality of focuses are caused for one laser beam. <P>SOLUTION: An optical pickup device includes a semiconductor laser 101c and an objective lens 109. A laser beam for CD emitted from the semiconductor laser 101c is converged on two focuses by a diffraction grating formed on an incident plane of the objective lens 109. If one side of focus out of two focuses is positioned at a recording layer of a CD, light converged on the other focus is reflected by the recording layer and becomes stray light. A region in which only signal light is included is caused on a photodetector 114 by luminous flux-scattering action by an angle adjustment element 112 and astigmatism action by a detecting lens 113. A sensor of the photodetector 114 is arranged in this region. <P>COPYRIGHT: (C)2011,JPO&INPIT |
