Patent ID: 6363046
Filing Date: 2002-03-26
Classification: G11B

Abstract:
An optical recording/pickup head for use with first and second types of optical disks, in which distances from the optical recording/pickup head to the information recording surfaces of the first and second types of optical disks differ from each other, and information is recorded and reproduced by first and second light beams having respectively different wavelengths, the optical recording/pickup head comprising:a first light source to emit the first light beam; a first photodetector; a second light source to emit the second light beam; a second photodetector; an objective lens to focus the first light beam and the second light beam as beam spots on the respective information recording surfaces of the first and second types of optical disks; optical path alteration means to transfer the first light beam incident from the first light source to the objective lens and to transfer the first light beam reflected from the first type optical disk and incident from the objective lens to the first photodetector, and to transfer the second light beam incident from the second light source to the objective lens and to transfer the second light beam reflected from the second type optical disk and incident from the objective lens to the second photodetector, and a variable aperture, located on an optical path between the optical path alteration means and the objective lens, to totally transmit the first light beam incident from the optical path alteration means to the objective lens, and to transmit only part of the second light beam incident from the optical path alteration means to the objective lens, wherein the objective lens focuses the first and second light beams incident from the optical path alteration means and transmitted by the variable aperture on the information recording surfaces of the first and second types of optical disks, respectively, so that the beam spots each have a main lobe formed on the respective information recording surfaces of the first and second types of optical disks.