Optical head including a semiconductor laser having a non-scatter area to diffuse incident light beams

摘要

An optical head for optical recording and reproducing apparatuses is disclosed, which comprises a semiconductor laser, a mirror for reflecting a light beam emitted from the semiconductor laser, a diffraction grating for dividing the light beam into zero order, plus and sinus first-order beams, a holographic diffraction grating being arranged at an optical path of the beams divided by the diffraction grating, an objective lens for focusing the beams on a disk and causing the beams reflected from the disk to be incident on the holographic diffraction grating to diffract the beams, and a photodetector for detecting a tracking error signal by receiving the beams diffracted by the holographic diffraction grating. The semiconductor laser has a beam incident area which the beam reflected from the disk is incident. The beam incident area acts to deflect the incident beam. As a result, the optical head is able to obtain the stable tracking error signal.