| 摘要 |
An optical storage device capable of at least reproducing information recorded on first and second optical storage media different in distance from a medium surface on which a light beam is incident to a recording surface and in operating wavelength. The optical storage device includes a first light emitting element for emitting a light beam having a first wavelength, a second light emitting element for emitting a light beam having a second wavelength, a first photodetector for detecting a reproduction signal from a light beam reflected on the first optical storage medium, a second photodetector for detecting a reproduction signal from a light beam reflected on the second optical storage medium, and a beam splitter for combining optical paths of the light beams emitted from the first and second light emitting elements. The optical storage device further includes an objective lens for optimally focusing the light beam emitted from the first light emitting element onto the first optical storage medium, and an optical element for producing a rotationally symmetrical aberration compensating for a wave aberration occurring on the second optical storage medium, in the light beam emitted from the second light emitting element.
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