Patent US3910685A successfully refreshed from Google Patents.
US3910685A
Expired / Lapsed
US
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Three element objective lens with aspheres on rear surfaces of first and second elements
Assignee: Eastman Kodak Co
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Filing: 1974-11-05
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Granted: 1975-10-07
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Expires: 1994-11-05
Abstract
Abstract A three element objective lens having a front positive meniscus element, a middle negative element and a rear positive biconcave element. Improved optical performance at a relative aperture of at least f/1.33 is achieved by the use of aspheres on the rear surfaces of the first and second elements.
Inventors
- 👤 Donald Dejager
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:07
CPC Classifications
G; G02; G02B; G02B9/00; G02B9/12; G02B9/14; G02B9/16; G02B13/00; G02B13/18; G02B3/00; G02B3/02; G02B3/04
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
48 words
A three element lens comprising a front positive element, a middle negative and a rear positive element, said lens having aspheric surfaces on the rear of said front and middle elements and wherein said lens has a focal length of 10.00mm when constructed according to the following parameters:
Claim 2
Dependent Claim
48 words
A three element lens comprising a front positive element, a middle negative and a rear positive element, said lens having aspheric surfaces on the rear of said front and middle elements and wherein said lens has a focal length of 10.00mm when constructed according to the following parameters:
Claim 3
Dependent Claim
50 words
A three element lens comprising a front positive element, a middle negative element and a rear positive element, said lens having aspheric surfaces on the rear of said front and middle elements and wherein said lens has a focal length of 9.00 mm when constructed according to the following parameters:
Claim 4
Dependent Claim
50 words
A three element lens comprising a front positive element, a middle negative element and a rear positive element, said lens having aspheric surfaces on the rear of said front and middle elements and wherein said lens has a focal length of 9.00 mm when constructed according to the following parameters:
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) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |