| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress decrease of a light volume of a reflection light irradiated on a photo-detector even when a polarization component of the reflection light from an optical recording medium is changed. <P>SOLUTION: The optical pickup device is provided with: a laser source for emitting laser beam; an objective lens irradiating the optical recording medium with the laser beam; the photo-detector for receiving the reflection light of the laser beam reflected from the optical recording medium; a half mirror interposed on a light path between the laser source and the objective lens, for reflecting the laser beam to a direction of the objective lens and transmitting the reflection light to a direction of the photo-detector; and an astigmatism addition member interposed on the light path between the half mirror and the photo-detector, for adding the astigmatism to the reflection light. The astigmatism addition member includes such control films that a first transmittance with respect to a polarization component in a first direction contained in the reflection light and a second transmittance with respect to a polarization component in a second direction orthogonal to the first direction are almost equal. <P>COPYRIGHT: (C)2013,JPO&INPIT |
