Aberration detection device and optical information recording and reproducing apparatus
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTetsuo Saimi, Shin-ichi Tanaka
Life of this patent
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Abstract
A returning light beam emitted by a light source and reflected by an optical disk is separated by a half mirror, and partitioned and deflected at a hologram into a light beam passing a first region and a light beam passing a second region. The light beam passing the first region is received by a plurality of photo-detectors, and the aberration is detected by comparing the resulting signals. Based on the aberration detection, the aberration of an optical system can be reduced by driving an aberration correction element in real-time.
Claims14
An aberration detection device comprising:
- a radiation source for emitting a light beam;
- an object lens for focussing the light beam on an information carrier;
- a light beam splitter for separating a returning light beam that has been reflected by the information carrier and passed through said object lens from an incoming light beam;
- a light deflector for partitioning and deflecting the returning light beam, that has been separated by said light beam splitter, into a light beam passing a first region and a light beam passing a second region;
- and
- a plurality of light detectors for receiving a deflected light beam passing through the first region;
- wherein an aberration is detected by comparing signals from said plurality of light detectors.
An aberration detection device comprising:
- a radiation source for emitting a light beam;
- an object lens for focussing the light beam on an information carrier;
- a light deflector for partitioning a returning light beam that has been reflected by the information carrier and passed through said object lens into a light beam passing a first region and a light beam passing a second region, and deflecting the light beam passing the first region away from said radiation source;
- and
- a plurality of light detectors for receiving a deflected light beam passing through the first region;
- wherein an aberration is detected by comparing signals from said plurality of light detectors.
An optical information recording and reproducing apparatus for (i) recording information onto a recordable and reproducible information carrier having a plurality of information recording layers, and an optical separation layer sandwiched between the information recording layers and/or (ii) reproducing the recorded information;
- said optical information recording and reproducing apparatus comprising:
- a radiation source for emitting a light beam;
- a light beam focussing system for focussing a light beam emitted by said radiation source onto at least one of the plurality of information recording layers;
- and
- a spherical aberration correction system formed in one piece with said light beam focussing system.
An optical information recording and reproducing apparatus for (i) recording information onto a recordable and reproducible information carrier having a plurality of information recording layers, and an optical separation layer sandwiched by the information recording layers and/or (ii) reproducing the recorded information;
- said optical information recording and reproducing apparatus comprising:
- a radiation source for emitting a light beam;
- a light beam focussing system for focussing a light beam emitted by said radiation source onto at least one of the plurality of information recording layers;
- and
- a spherical aberration correction system formed in one piece with said light beam focussing system and arranged between said radiation source and said light beam focussing system,
- wherein said spherical aberration correction system can change an optical phase that is constant in a circumferential direction, and varies in a radial direction, with respect to an optical axis of said light beam focussing system.
Dependencies are inferred from the claim text.