Patent US4828373A successfully refreshed from Google Patents.
US4828373A
Expired / Lapsed
US
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Aspherical single lens
Assignee: Canon Inc
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Filing: 1987-10-16
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Granted: 1989-05-09
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Expires: 2007-10-16
Abstract
Abstract An aspherical single lens of compact construction and good image-forming performance which is obtained by shaping the first surface into such an aspherical configuration the curvature radius of which increases gradually toward the periphery from the center while satisfying the following conditions: 0.42<q<1.3 (a) and 0.5(f-1)<d<1.2f (b) wherein, q=-r 1 /r 2 , r 1 is the curvature radius in the vicinity of the optical axis of the first surface, r 2 is the curvature radius of the second surface, f is the focal length and d is the thickness of the lens.
Inventors
- 👤 Shigeyuki Suda
- 👤 Masayuki Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:17
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B13/00; G02B13/18; G02B3/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
142 words
An aspherical single lens for use as an objective lens of an optical memory, comprising: a first surface of aspherical configuration, said first surface being configured in such a manner that a radius of curvature thereof increases gradually toward the periphery from the area in the vicinity of the optical axis; and a second surface of spherical configuration on an opposite side from said first surface, wherein said second surface is positioned to face an object to which a light beam is directed through said objective lens, and satisfying the following conditions: 0.42<q<1.3, where q=-r.sub.1 /r.sub.2, and 0.5(f-1)<d<1.2f wherein r 1 is the curvature radius in the vicinity of the optical axis of the first surface; r 2 is the curvature radius of the second surface; f is the focal length of the lens; and d is the lens thickness on axis.
Claim 2
Dependent Claim
142 words
An aspherical single lens for use as an objective lens of an optical memory, comprising: a first surface of aspherical configuration, said first surface being configured in such a manner that a radius of curvature thereof increases gradually toward the periphery from the area in the vicinity of the optical axis; and a second surface of spherical configuration on an opposite side from said first surface, wherein said second surface is positioned to face an object to which a light beam is directed through said objective lens, and satisfying the following conditions: 0.42<q<1.3, where q=-r.sub.1 /r.sub.2, and 0.5(f-1)<d<1.2f wherein r 1 is the curvature radius in the vicinity of the optical axis of the first surface; r 2 is the curvature radius of the second surface; f is the focal length of the lens; and d is the lens thickness on axis.
Claim 3
Dependent Claim
20 words
An aspherical single lens according to claim 1, further comprising a pupil located in a range where the lens exists.
Claim 4
Dependent Claim
159 words
An aspherical single lens for imaging a light beam emitted from a semiconductor laser on an optical information recording medium, passing through a transparent substrate having a thickness of 1.1-1.5 mm., comprising: a first surface of aspherical configuration, said first surface being configured in such a manner that a radius of curvature thereof increases gradually toward the periphery from the area in the vicinity of the optical axis; and a second surface of spherical configuration on the opposite side of said first surface, wherein said second surface is positioned to face an object to which a light beam is directed through said objective lens, and satisfying the following conditions: 0.42<q<1.3, where q=-r.sub.1 /r.sub.2, and 0.5(f-1)<d<1.2f wherein r 1 is the curvature radius in the vicinity of the optical axis of the first surface; r 2 is the curvature radius of the second surface; f is the focal length of the lens; and d is the lens thickness on axis.
Claim 5
Dependent Claim
159 words
An aspherical single lens for imaging a light beam emitted from a semiconductor laser on an optical information recording medium, passing through a transparent substrate having a thickness of 1.1-1.5 mm., comprising: a first surface of aspherical configuration, said first surface being configured in such a manner that a radius of curvature thereof increases gradually toward the periphery from the area in the vicinity of the optical axis; and a second surface of spherical configuration on the opposite side of said first surface, wherein said second surface is positioned to face an object to which a light beam is directed through said objective lens, and satisfying the following conditions: 0.42<q<1.3, where q=-r.sub.1 /r.sub.2, and 0.5(f-1)<d<1.2f wherein r 1 is the curvature radius in the vicinity of the optical axis of the first surface; r 2 is the curvature radius of the second surface; f is the focal length of the lens; and d is the lens thickness on axis.
Claim 6
Dependent Claim
20 words
An aspherical single lens according to claim 3, further comprising a pupil located in a range where the lens exists.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |