Patent ID: 6044048
Filing Date: 2000-03-28
Classification: G11B

Abstract:
An optical pickup device comprising:a light source for radiating a light beam;a light splitting element for splitting the light beam into at least three light beam portions;a optical path bending mirror for bending optical paths of said light beam portions;an objective lens for focusing the light beam portions from said optical path bending mirror onto a signal recording surface of said optical disc;a biaxial actuator for supporting said objective lens and for selectively moving said objective lens in at least one of a focusing direction and a tracking direction relative to said optical disc;light splitting means for separating the light beam portions focused on the signal recording surface from return light beam portions reflected from the signal recording surface, the return light beam portions having optical paths bent by said optical path bending mirror; anda photodetector having three light receiving elements for receiving the return light beam portions,wherein optical paths from said light splitting means to said optical path bending mirror are set at an angle of approximately 45.degree. relative to a direction of a recording track of the optical disc, andwherein said photodetector is configured and arranged such that:during reproduction of an optical disc having a first recording density, the photodetector detects focusing error signals using the light receiving element disposed at the center of said three light receiving elements and detects tracking error signals using the remaining two light receiving elements of said three light receiving elements, andduring reproduction of an optical disc having a second recording density, higher than the first recording density, the photodetector detects focusing error signals and tracking error signals using the light receiving element disposed at the center of said three light receiving elements.