Patent US3768890A successfully refreshed from Google Patents.
US3768890A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Internal focusing wide angle eyepiece
Assignee: Nikon Corp
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Filing: 1972-06-12
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Granted: 1973-10-30
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Expires: 1992-06-12
Abstract
Abstract A wide angle eyepiece for an internal focusing optical system of a viewing instrument comprises six elements. As viewed axially from rear to front, the eyepiece includes a biconvex doublet eyelens having a negative meniscus element and a biconvex element cemented together, a first positive meniscus single lens concaved toward the eye, a second positive meniscus single lens convexed toward the eye, and a positive meniscus doublet field lens having a biconvex element and a biconcave element cemented together. The field lens and at least one of the single lenses are axially movable together for focusing.
Inventors
- 👤 K Osawa
- 👤 M Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:40
CPC Classifications
G; G02; G02B; G02B25/00; G02B25/001
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
98 words
A wide angle eyepiece for an internal focusing optical system of a viewing instrument comprising, axially from rear to front, a biconvex doublet eyelens having a negative meniscus element curved towards the eye and a biconvex element cemented to each other, a first positive meniscus single lens concaved toward the eye, a second positive meniscus single lens convexed toward the eye, and a positive meniscus doublet field lens having, a biconvex element and a biconcave element cemented to each other, said field lens and at least one of said single lenses being axially movable in unison for focusing.
Claim 2
Dependent Claim
98 words
A wide angle eyepiece for an internal focusing optical system of a viewing instrument comprising, axially from rear to front, a biconvex doublet eyelens having a negative meniscus element curved towards the eye and a biconvex element cemented to each other, a first positive meniscus single lens concaved toward the eye, a second positive meniscus single lens convexed toward the eye, and a positive meniscus doublet field lens having, a biconvex element and a biconcave element cemented to each other, said field lens and at least one of said single lenses being axially movable in unison for focusing.
Claim 3
Dependent Claim
118 words
A wide angle eyepiece according to claim 1, wherein the following data is satisfied: Relative aperture F/3.6; Angle of view 2 Alpha 68*R1 5724.138 d1 6.897 n1 1.80518 Nu 1 25.5 R2 218.138 d2 37.931 n2 1.65160 Nu 2 58.5 R3 -126.986 d3 1.379 R4 -11046.9 d4 24.138 n3 1.62041 Nu 3 60.3 R5 - 232.759 (A) (B) (C) R6 266.414 d5 55.172 - 31.034 - 6.897 d6 20.690 n4 1.62041 Nu 4 60.3 R7 5551.724 d7 1.379 R8 186.207 d8 58.621 n5 1.62041 Nu 5 60.3 R9 -152.331 d9 6.897 n6 1.80518 Nu 6 25.5 R10 334.004 (A) (B) (C) Total focal length f 104.8mm - 100.0mm - 95.6mm Back focus B.f. 4.3mm - 16.9mm - 28.5mm
Claim 4
Dependent Claim
117 words
A wide angle eyepiece according to claim 1, wherein the following data is satisfied: Relative aperture F/3.6; Angle of view 2 Alpha 68*R1 6424.828 d1 6.897 n1 1.80518 Nu 1 25.5 R2 245.034 d2 37.931 n2 1.65160 Nu 2 58.5 R3 -124.69 (A) (B) (C) d3 41.379 - 24.138 - 6.897 R4 -11046.9 d4 24.138 n3 1.62041 Nu 3 60.3 R5 -232.759 d5 1.379 R6 266.414 d6 20.690 n4 1.62041 Nu 4 60.3 R7 5551.724 d7 1.379 R8 186.207 d8 58.621 n5 1.62041 Nu 5 60.3 R9 -152.331 d9 6.897 n6 1.80518 Nu 6 25.5 R10 287.323 (A) (B) (C) Total focal length f 104.7mm - 100mm -95.7mm Back focus B.f. 20.9mm - 25.0mm - 28.8 mm
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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |