| 摘要 |
PURPOSE: To improve detection sensitivity and to make the optical pickup thin on the other hand by fitting a hologram laser unit and a mirror onto a pedestal so as to provide a fixed angle on a surface parallel with the face of a disk. CONSTITUTION: The light emitted from a hologram laser unit 1 parallelly with the face of a disk 5 is diffracted by a diffraction grating part 2 and afterwards, the direction of diffraction on the disk 5, namely, a straight line 7c connecting sub-beams 7a and 7b is matched with a projection 10a from the hologram laser unit 1 to the face of the disk 5 of an optical axis 10 directed toward a mirror 3 having the angle of 45 deg. to the face of the disk 5 by the mirror 3. Namely, the straight line 7c connecting the sub-beams 7a and 7b has an angle θ to a straight line direction 11 of a track 6 and in such a state, tracking detection sensitivity can be made maximum. |
