Patent US4842388A successfully refreshed from Google Patents.
US4842388A
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Single optical lense with diffraction limit converging capability and wide field angle
Assignee: Panasonic Holdings Corp
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Filing: 1987-06-11
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Granted: 1989-06-27
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Expires: 2007-06-11
Abstract
Abstract A single lens having first and second aspherical surfaces each having a positive power is usable for, an objective lens of an optical pickup for an optical recording medium. The lens satisfies the following conditions: 0.1<¦m¦<0.5 0.9<(d/f)<1.2 where m denotes magnification; d denotes thickness of the lens; and f denotes focal length of the lens.
Inventors
- 👤 Yasuhiro Tanaka
- 👤 Yasuo Nakajima
- 👤 Yoshitomi Nagaoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:17
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B3/04
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
40 words
A single lens having first and second aspherical surfaces each having a positive power, satisfying the following conditions: 0.1<|m|<0.5 (1) 0.9<(d/f)<1.2 (2) where m denotes magnification; d denotes thickness of the lens; and f denotes focal length of the lens.
Claim 2
Dependent Claim
40 words
A single lens having first and second aspherical surfaces each having a positive power, satisfying the following conditions: 0.1<|m|<0.5 (1) 0.9<(d/f)<1.2 (2) where m denotes magnification; d denotes thickness of the lens; and f denotes focal length of the lens.
Claim 3
Dependent Claim
18 words
The single lens in accordance with claim 1, having a refractive index n satisfying a condition of 1.6<n.
Claim 4
Dependent Claim
116 words
The single lens in accordance with claim 1, wherein the first surface has a conic constant K 1 satisfying a condition of 0<K 1 <1 under the condition that the aspherical surface is expressed by the following equation: ##EQU2## where X denotes a distance from a tangential plane at the vertex of the aspherical surface to a point on the aspherical surface at a height h from the optical axis of the lens; h denotes the height from the optical axis; C denotes surface curvature at the vertex of the aspherical surface; K denotes conic constant; and A 2 i denotes 2i-th order aspherical surface coefficient, in which i represents an integer of at least 2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |