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US 6,856,584 B2Granted
Aberration detection device and optical information recording and reproducing apparatus
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTetsuo Saimi, Shin-ichi Tanaka
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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.
Claims22
An aberration detection device comprising:
- a radiation source for emitting a light beam;
- an object lens for focusing 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 first light beam passing a first region and a second light beam passing a second region, and diffracting the first light beam that has passed the first region away from said radiation source;
- and
- a first light detector for receiving the first light beam and a second light detector fro receiving the second light beam;
- wherein said first light detector and said second light detector each comprise a photo-detector partitioned into at least two portions,
- said first light detector and said second light detector are arranged such that the first light beam and the second light beam are each irradiated onto a corresponding partition line of said first light detector and said second light detector,
- the object lens has a numerical aperture of at least 0.6, and
- a spherical aberration, a coma aberration or an astigmatism is detected and identified individually from an output signal from said first light detector and said second light detector.
6 more elements
An aberration detection device comprising:
- a radiation source for emitting a light beam;
- an object lens for focusing 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 first light beam passing a first region and a second light beam passing a second region, and diffracting the first light beam that has passed the first region away from said radiation source;
- and
- a first light detector for receiving the first light beam and a second light detector for receiving the second light beam;
- wherein said first light detector and said second light detector each comprise a photo-detector partitioned into at least two portions,
- said first light detector and said second light detector are arranged such that the first light beam and the second light beam are each irradiated onto a corresponding partition line of said first light detector and said second light detector,
- an optical system is configured such that a spherical aberration WEF(SA) is at least 35 mλ, where WFE(SA) is the spherical aberration generated by a portion of the information carrier pass by the light beam and λ is the wavelength of the light beam, and
- the spherical aberration is detected and identified from an output signal from said first light detector and said second light detector.
6 more elements
An aberration detecting device comprising:
- a radiation source for emitting a light beam;
- an object lens for focusing 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 first light beam passing a first region and a second light beam passing a second region, and diffracting the first light beam that has passed the first region away from said radiation source;
- and
- a first light detector for receiving the first light beam and a second light detector for receiving the second light beam;
- wherein said first light detector and said second light detector each comprise a photo-detector partitioned into at least two portions,
- said first light detector and said second light detector are arranged such that the first light beam and the second light beam are each irradiated onto a corresponding partition line of said first light detector and said second light detector,
- said first light detector and said second light detector are arranged adjacent to each other, and
- a spherical aberration, a coma aberration or an astigmatism is detected and identified individually from an output signal from said first light detector and said second light detector.
6 more elements
An aberration detection device comprising:
- a radiation source for emitting a light beam;
- an object lens for focusing 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 first light beam passing a first region and a second light beam passing a second region, and diffracting the first light beam that has passed the first region away from said radiation source;
- and
- a first light detector for receiving the first light beam and a second light detector for receiving the second light beam;
- wherein said first light detector and said second light detector each comprise a photo-detector partitioned into at least two portions,
- said first light detector and said second light detector are arranged such that the first light beam and the second light beam are each irradiated onto a corresponding partition line of said first light detector and said second light detector,
- the partition line of said first light detector and the partition line of said second light detector are arranged on a common straight line, and
- a spherical aberration, a coma aberration or an astigmatism is detected and identified individually from an output signal from said first light detector and said second light detector.
6 more elements
An aberration detection device comprising:
- a radiation source for emitting a light beam;
- an object lens for focusing the light beam on a 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 first light beam passing a first region and a second light beam passing a second region, and diffracting the first light beam that has passed the first region away from said radiation source;
- and
- a first light detector for receiving the first light beam and a second light detector for receiving the second light beam;
- wherein said first light detector and said second light detector each comprise a photo-detector partitioned into at least two portions,
- said first light detector and said second light detector are arranged such that the first light beam and the second light beam are each irradiated onto a corresponding partition line of said first light detector and said second light detector,
- said first light detector and said second light detector are arranged on the same side with respect to a plane including an optical axis of a light beam, passing through the
- light deflector without being deflected, in the returning light beam, and
- a spherical aberration, a coma aberration or an astigmatism is detected and identified individually from an output signal from said first light detector and said second light detector.
7 more elements
Dependencies are inferred from the claim text.