Patent ID: 6707615
Filing Date: 2004-03-16
Classification: G11B

Abstract:
An optical pickup apparatus for recording or reproducing information on or from an optical disc, said apparatus comprising:a light source radiating a laser beam; an optical detector detecting reflected light from the optical disc; a collimator lens converting the radiated light of said light source into a fine divergent pencil of rays; and an objective lens that focuses said rays on said optical disc, wherein: said collimator lens has a surface that is curved to form a wavefront shape that increasingly corrects a coma aberration of the radiated light in correspondence to a radial distance between a center of the collimator lens and a position at which said radiated light intersects said collimator lens and a ratio of sine amount (SIN &thgr;2/SIN &thgr;1) between a sine amount (SIN &thgr;1) of the radiated light from said light source with respect to an optical axis and a sine amount (SIN &thgr;2) of the light after radiating through said collimator lens with respect to the optical axis increases in substantial proportion to a square of said radial distance.