Patent US4909616A successfully refreshed from Google Patents.
US4909616A
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Optical system for recording and reproducing an optical information medium
Assignee: Konica Minolta Inc
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Filing: 1989-01-24
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Granted: 1990-03-20
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Expires: 2009-01-24
Abstract
Abstract Generally, in an optical system for recording and reproducing an optical information medium, a semi-conductor laser is used as a light source, an approximately parallel luminous flux is obtained by a collimator lens, and thereafter it is converged on a recording surface by an objective lens. If the semi-conductor laser causes a mode hop to abruptly change an oscillating wavelength, an error results when the objective lens has a chromatic aberration. A collimator lens with a reverse chromatic abberation can be used so that various conventional objective lens may be utilized as they are without any error as described.
Inventors
- 👤 Norikazu Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:00
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/24; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1372; G11B7/1376
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
77 words
An optical system for recording, reproducing, or recording and reproducing an optical information medium comprising at least a laser light source, a collimator lens having a positive focal length, and an objective lens converging luminous flux from said collimator lens, divergent light from said light source being converged on an information recording surface, characterized in that said collimator lens has a chromatic aberration of over-correction in the neighbourhood of the oscillating wavelength of said laser light source.
Claim 2
Dependent Claim
77 words
An optical system for recording, reproducing, or recording and reproducing an optical information medium comprising at least a laser light source, a collimator lens having a positive focal length, and an objective lens converging luminous flux from said collimator lens, divergent light from said light source being converged on an information recording surface, characterized in that said collimator lens has a chromatic aberration of over-correction in the neighbourhood of the oscillating wavelength of said laser light source.
Claim 3
Dependent Claim
27 words
An optical system as set forth in claim 1, wherein said objective lens comprises a single lens, at least one surface of which is an aspherical surface.
Claim 4
Dependent Claim
17 words
An optical system as set forth in claim 2, wherein said objective lens has a focussing function.
Claim 5
Dependent Claim
18 words
An optical system as set forth in claim 1, wherein said laser light source comprises a semiconductor laser.
Claim 6
Dependent Claim
104 words
In an optical system comprising at least a laser light source, a collimator lens having a positive focal length and an objective lens for further converging luminous flux from said collimator lens, divergent light from said light source being converged on an information recording surface, an optical system for recording, reproducing or recording and reproducing an optical information medium characterized in that said objective lens is constituted by a resin single lens at least one surface of which is an aspherical surface, and said collimator lens has a chromatic aberration of over-correction in the neighbourhood of the oscillating wavelength of said laser light source.
Claim 7
Dependent Claim
104 words
In an optical system comprising at least a laser light source, a collimator lens having a positive focal length and an objective lens for further converging luminous flux from said collimator lens, divergent light from said light source being converged on an information recording surface, an optical system for recording, reproducing or recording and reproducing an optical information medium characterized in that said objective lens is constituted by a resin single lens at least one surface of which is an aspherical surface, and said collimator lens has a chromatic aberration of over-correction in the neighbourhood of the oscillating wavelength of said laser light source.
Claim 8
Dependent Claim
18 words
An optical system as set forth in claim 5, wherein said laser light source comprises a semiconductor laser.
Claim 9
Dependent Claim
17 words
An optical system as set forth in claim 6, wherein said objective lens has a focussing function.
Claim 10
Dependent Claim
73 words
A recording and reproducing apparatus for converging light from a laser light source on a recording surface of an information recording medium through a collimator lens and an objective lens to record information on said recording medium or reproduce information on the recording medium, characterized in that the use of said collimator lens is made which has a chromatic aberration of over-correction in the neighbourhood of the oscillating wavelength of said laser light.
Claim 11
Dependent Claim
73 words
A recording and reproducing apparatus for converging light from a laser light source on a recording surface of an information recording medium through a collimator lens and an objective lens to record information on said recording medium or reproduce information on the recording medium, characterized in that the use of said collimator lens is made which has a chromatic aberration of over-correction in the neighbourhood of the oscillating wavelength of said laser light.
Claim 12
Dependent Claim
20 words
A recording and reproducing apparatus as set forth in claim 8, wherein said laser light source comprises a semiconductor laser.
Claim 13
Dependent Claim
19 words
A recording and reproducing apparatus as set forth in claim 8, wherein said objective lens has a focussing function.
References Cited (Backward Citations)
US4635244A
Cited
US4641929A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-19 | 2001-09-18 | 2002-03-20 | $7700.00 | Window Closed / Lapsed |