PURPOSE: To obtain an optical pickup preventing the movement of a light spot on a photodetecting face of a photoelectric detector by providing the 2nd optical member to form a minimum blur circle on the photodetecting face at focusing and a displacing means displaced in the same direction as that of the displacement of an objective lens.
CONSTITUTION: A toric lens 72 is arranged between a convex lens 71 and a detector 12. This toric lens 72 is moved in the same direction as the said tracking displacement in the same plane optically in interlocking with the tracking displacement of the objective lens. Thus, the minimum blur circle is produced on a focal plane of the convex lens 71 and orthogonal focal lines are produced before and after the said focal plane. Then the toric lens 72 is moved in the same direction as that of the tracking displacement of the objective lens. Thus, the minimum blur circle on the photodetecting plane is made independent of the displacement of the objective lens and fixed to an identical position.
MIZUNOE KATSUZOU
YANAI JIYUNICHI
