| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup in which offset of an objective lens is corrected without using a plurality of beams, and also to provide an optical recording and reproducing apparatus, and a tracking error detecting method. <P>SOLUTION: In the optical pickup, a diffraction element is provided in an optical path in which light is reflected by an optical recording medium and proceeded to a light receiving part, the light diffracted by this diffraction element has constitution having astigmatism of a five order, that is, W(ρ,θ) = Z(4ρ<SP>4</SP>-3ρ<SP>2</SP>)×sinθ(where, (ρ,θ) indicates radius and angle of polar coordinate making an optical axis as an original point, and Z indicates a coefficient expressing aberration quantity). Since intensity distribution of brightness and darkness is caused in a push-pull modulation region, a push-pull component is canceled, and only offset of the objective lens is detected. <P>COPYRIGHT: (C)2007,JPO&INPIT |
