Patent ID: 7826330
Filing Date: 2010-11-02
Classification: G11B

Abstract:
1. An optical pickup device comprising: a light source for emitting a light beam having a divergent angle large in a vertical direction perpendicular to an information recording face of an optical disc and small in a parallel direction; a collimator lens for converting the light beam emitted from the light source into parallel light; an objective lens for converging the light beam to the optical disc; an extending portion in which a light flux transversal width as the width of the parallel direction with respect to the information recording face of the optical disc of the light beam converted into the parallel light by the collimator lens is extended until a final light flux diameter as the diameter of the light beam at an incident time to the objective lens; and a prism in which a light flux longitudinal width as the width of a direction perpendicular to the information recording face of the optical disc of the extended light beam is extended until the final light flux diameter, and the light beam is emitted to the objective lens; wherein the collimator lens converts the light beam into the parallel light such that the light flux longitudinal width and the light flux transversal width in the light beam become smaller than the final light flux diameter.