US5280464A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical disk apparatus having a focusing error correcting system
Assignee: Pentax Corp
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Filing: 1991-08-07
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Granted: 1994-01-18
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Expires: 2011-08-07
Abstract
Abstract An optical system of an optical disk apparatus having plural optical elements characterized in that the optical element having aberration which can counterbalance the wave front aberration of the whole optical system is disposed, or a direction of aberration of each existing optical element is adjusted in order to correct the wave front aberration.
Inventors
- 👤 Tsuyoshi Itoh
- 👤 Isao Okuda
- 👤 Toshiyuki Kase
- 👤 Hiroshi Nishikawa
- 👤 Ryota Ogawa
- 👤 Masahiro Oono
- 👤 Koichi Maruyama
- 👤 Makoto Iki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:41
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0908; G11B7/0909; G11B7/12; G11B7/135; G11B7/1365; G11B7/1392; G11B7/13922
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
85 words
An optical system of an optical disk apparatus comprising: a light source; a converging lens for converging a light beam emitted from said light source onto an optical disk; and an aberration correcting element for setting off wave front aberration so that astigmatism of said light beam at said optical disk is corrected, said aberration correcting element being disposed between said light source and said optical disk; wherein said aberration correcting element includes strain to add wave front aberration to a light beam passing therethrough.
Claim 2
Dependent Claim
85 words
An optical system of an optical disk apparatus comprising: a light source; a converging lens for converging a light beam emitted from said light source onto an optical disk; and an aberration correcting element for setting off wave front aberration so that astigmatism of said light beam at said optical disk is corrected, said aberration correcting element being disposed between said light source and said optical disk; wherein said aberration correcting element includes strain to add wave front aberration to a light beam passing therethrough.
Claim 3
Dependent Claim
143 words
An optical system of an optical disk apparatus having plural optical elements, said optical disk apparatus comprising: a light source for emitting a light beam; an objective lens for converging said light beam onto an optical disk; means for detecting a focus error signal by an astigmatism method; means for driving said objective lens along the optical axis according to said focus error signal; and a wave front aberration correcting element for setting off wave front aberration so that astigmatism of said light beam at said optical disk is corrected, said aberration correcting element being disposed in a parallel light beam between said light source and said optical disk; wherein said wave front aberration correcting element corrects the wave front aberration in a rotated coordinate system, the axes of which form angles of 45° with radial and tangential directions of the optical disk.
Claim 4
Dependent Claim
143 words
An optical system of an optical disk apparatus having plural optical elements, said optical disk apparatus comprising: a light source for emitting a light beam; an objective lens for converging said light beam onto an optical disk; means for detecting a focus error signal by an astigmatism method; means for driving said objective lens along the optical axis according to said focus error signal; and a wave front aberration correcting element for setting off wave front aberration so that astigmatism of said light beam at said optical disk is corrected, said aberration correcting element being disposed in a parallel light beam between said light source and said optical disk; wherein said wave front aberration correcting element corrects the wave front aberration in a rotated coordinate system, the axes of which form angles of 45° with radial and tangential directions of the optical disk.
Claim 5
Independent Claim
107 words
A method for setting off astigmatism of an optical system of an optical disk apparatus, said optical system including plural optical elements, said plural optical elements including a light source, a collimator lens, beam shaping prisms, a beam splitter, and an objective lens, said method comprising the steps of: assembling said plural optical elements at predetermined positions; determining the direction of astigmatism present in said plural optical elements; and adjusting at least one of said plural optical elements so that astigmatism of said plural optical elements are counterbalanced at least by one other optical element and astigmatism of a light beam at an optical disk is corrected.
Claim 6
Independent Claim
107 words
A method for setting off astigmatism of an optical system of an optical disk apparatus, said optical system including plural optical elements, said plural optical elements including a light source, a collimator lens, beam shaping prisms, a beam splitter, and an objective lens, said method comprising the steps of: assembling said plural optical elements at predetermined positions; determining the direction of astigmatism present in said plural optical elements; and adjusting at least one of said plural optical elements so that astigmatism of said plural optical elements are counterbalanced at least by one other optical element and astigmatism of a light beam at an optical disk is corrected.
Claim 7
Dependent Claim
99 words
An optical system of an optical disk apparatus comprising: a light source; a converging lens for converging a light beam emitted from said light source onto an optical disk; and an aberration correcting element for setting off wave front aberration so that astigmatism of said light beam at said optical disk is corrected, said aberration correcting element being disposed between said light source and said optical disk; wherein said aberration correcting element corrects the wave front aberration in a rotated coordinate system, the axes of which form angles of 45° with radial and tangential directions of the optical disk.
Claim 8
Dependent Claim
99 words
An optical system of an optical disk apparatus comprising: a light source; a converging lens for converging a light beam emitted from said light source onto an optical disk; and an aberration correcting element for setting off wave front aberration so that astigmatism of said light beam at said optical disk is corrected, said aberration correcting element being disposed between said light source and said optical disk; wherein said aberration correcting element corrects the wave front aberration in a rotated coordinate system, the axes of which form angles of 45° with radial and tangential directions of the optical disk.
References Cited (Backward Citations)
US4643538A
Cited
JPS61109015A
Cited
US4709139A
Cited
US4807212A
Cited
US4812638A
Cited
US4805992A
Cited
US4822151A
Cited
US5121378A
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) | 1997-01-17 | 1997-07-19 | 1998-01-18 | $2000.00 | Window Closed / Lapsed |
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