Light Formation Apparatus and Control Method of Light Information Apparatus

摘要

When a spherical aberration generated on an optical recording medium is optically corrected, there has been a problem of irradiation power change of an output on an objective lens side due to a change of a signal level detected by a light quantity detector in response to the correction value. An optical information device is provided with a laser ( 2 ) for projecting optical beams; an objective lens ( 9 ) and the like for focusing the optical beams projected from the laser ( 2 ) on an optical recording medium ( 10 ); a spherical aberration correcting means ( 24 ), which is arranged on an optical axis of the optical beams connecting the laser ( 2 ) and the objective lens ( 9 ) and corrects a spherical aberration generated on the optical recording medium ( 10 ); a polarization beam splitter ( 5 ) for splitting the optical beams projected from the laser ( 2 ) into a plurality of beams; a light quantity detector ( 15 ) which receives one of the optical beams split by the polarization beam splitter ( 5 ) and outputs an electric signal corresponding to the receiving light quantity; a laser power control means ( 21 ), which controls the projection power of the laser beam source based on the electric signal from the light quantity detector ( 15 ); and a controller ( 23 ), which performs correction, such as to change the projection power of the laser ( 2 ) in response to a correction quantity of the spherical aberration correcting means ( 24 ).