| 摘要 |
PURPOSE:To obtain a distortion-less spot shape, to improve the quality of a focusing and a tracking error signals and to improve the reliability of information recording/reproducing. CONSTITUTION:In an optical head having a form in which a divergent beam from a laser light source 110 is made incident on light collecting elements 30, 40 through a beam splitter 120 and a reflection type hologram element, the light emitting axis 112 of the laser light source is arranged while inclining to the principal light beam 109 of an optical system and the intensity distribution of the divergent beam is deviated in advance from the principal light beam 109 of an optical system. Or, the entrance pupils of the light collecting elements(objective lenses) 30 40 are intentionally shifted and arranged. Consequently, the deviation of the intensity distribution in the divergent beam caused by interposing the beam splitter and the reflection type hologram element is compensated. Thus, the beam whose intensity distribution is almost symmetric is made incident on the entrance pupil of the light collecting element and a desired spot is formed on the recording medium. |
