Patent ID: 8305867
Filing Date: 2012-11-06
Classification: G11B

Abstract:
1. A lens for an optical pick-up formed by injection molding, comprising: a lens body having a first surface and a second surface; a flange part formed to protrude from a periphery of the lens body outward in a radial direction of the lens body, the flange part being formed to have a cylindrical outer circumferential surface centering on an optical axis of the lens; a lens installation surface formed at an outer edge part of the flange part on one of a side of the first surface and a side of the second surface; a recessed part formed as a part of the flange part such that a part of the cylindrical outer circumferential surface of the flange part is recessed toward the optical axis of the lens; and a gate root part which is a part of a gate of the lens, the gate root part being located at a central part of the recessed part, wherein: the gate root part has a flat surface which is in a same level with respect to the lens installation surface; and the gate root part lies on an optical axis side with respect to a virtual curved surface formed by extending the cylindrical outer circumferential surface of the flange part through the recessed part.