| 摘要 |
<p>An optical pickup apparatus comprises an optical waveguide (22) disposed to receive a light beam reflected by an optical recording medium (13), first and second focusing grating couplers (31,32) disposed side by side on the optical waveguide for coupling the reflected light beam into the optical waveguide and converging the optical wave guided through the optical waveguide to positions spaced from each other, and first and second photodetectors (24,25) secured to the optical waveguide for respectively detecting the optical waves converged by the first and second focusing grating couplers (31,32) so that reading out of recorded information, detection of tracking error and detection of focusing error can be effected. Or, the optical pickup apparatus comprises a grating lens disposed to receive and split the reflected light beam from an optical path of the light beam advancing toward the optical recording medium and to converge the reflected light beam, and a photodetector for detecting the reflected light beam passing through the grating lens so that reading out of recorded information, detection of a tracking error and detection of a focusing error can be effected.</p> |
