Optical pickup device

Abstract

An optical pickup device includes a semiconductor laser, a collimater lens, an optical member, a halfmirror, an objective lens, a collecting lens and a photodetector. The collimator lens collimates a laser beam from the semiconductor laser. The optical member diffracts the laser beam which has been collimated by the collimator lens outward along the direction of the shorter diameter of the laser beam, and emits a laser beam having a prescribed aspect ratio. The halfmirror passes the laser beam from optical member and reflects one half the light reflected from a signal recording surface of an optical disk to the photodetector. The objective lens focuses the laser beam on the signal recording surface. The collective lens collects the laser beam from the halfmirror. The photodetector detects the laser beam. Therefore, the optical pickup device is capable of converting the aspect ratio of the laser beam emitted from the semiconductor laser, and hence it becomes possible to irradiate the optical disk with the laser beam having sufficient power for recording a signal.

Dependencies are inferred from the claim text.