Patent ID: 7652970
Filing Date: 2010-01-26
Classification: G11B

Abstract:
1. An optical information apparatus, comprising: a laser light source which emits a light beam; a light beam convergence system which has an objective lens which converges a light beam emitted from said laser light source; a spherical aberration correction instrument which is arranged on an optical axis of said light beam which links said laser light source and said objective lens, and corrects a spherical aberration generated on said optical recording medium; a light separating instrument which separates into plural beams a light beam emitted from said laser light source; a light quantity detection instrument which receives either light beam separated by said light separating instrument, and outputting an electric signal according to an amount of received light; a laser power control instrument which controls outgoing power of said laser light source on the basis of said electric signal of said light quantity detection instrument; a laser power correction instrument which performs such correction that the outgoing power of said laser light source changes according to a correction amount of the spherical aberration on the basis of a relationship between an outgoing power of a light beam emitted from said objective lens and an amplitude of the electric signal which said light quantity detection instrument outputs, said correction amount provided to said aberration correction instrument to correct said spherical aberration; and a memory instrument which stores said relationship between the outgoing power of the light beam emitted from said objective lens and the amplitude of the electric signal, output by said light quantity detection instrument.