Patent US3848972A successfully refreshed from Google Patents.
US3848972A
Expired / Lapsed
US
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Large-aperture telephoto lens
Assignee: Olympus Corp
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Filing: 1973-04-11
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Granted: 1974-11-19
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Expires: 1993-04-11
Abstract
Abstract The present invention relates to photographic lens systems and more particularly, to a large-aperture telephoto lens system. The lens system of the present invention comprises four lenses, a first lens, second lens, third lens and fourth lens and is characterized in that various aberrations are favourably corrected by moving said fourth lens when photographing an object at a short distance.
Inventors
- 👤 S Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:07
CPC Classifications
G; G02; G02B; G02B9/00; G02B9/34; G02B13/00; G02B13/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
239 words
A large-aperture telephoto lens system comprising a first lens, a second lens, a third and a fourth lens, wherein said first lens is a positive meniscus lens with its convex surface positioned on the object side, said second lens is a cemented positive meniscus doublet lens with its convex surface positioned on the object side, said third lens is a negative meniscus lens with its convex surface positioned on the object side and said fourth lens is a cemented positive doublet lens, and said largeaperture telephoto lens system satisfying the following conditions: Nu 2 > Nu 3 > 45, n3 > n2, 0.3f > r4 > 0.15f (1) Nu 6 > Nu 5 > 45, n5 > n6, 0.3f > r9 > 0.15f (2)30 > Nu 4, n4 > 1.70 (3)f123 > OR = 2f (4) where reference symbols n2, n3, n5, n6 and n4, respectively represent refractive indexes of the front and rear lenses of the cemented second and fourth lenses and refractive index of the third lens, reference symbols Nu 2, Nu 3, Nu 4, Nu 5, and Nu 6, respectively, represent Abbe''s numbers of said lenses, reference symbols r4 and r9, respectively, represent radii of curvatures of cemented surfaces of said second and fourth lenses, reference symbol f123 represents the total focal length of said first, second and third lenses and reference symbol f represents the total focal length of the lens system as a whole.
Claim 2
Dependent Claim
239 words
A large-aperture telephoto lens system comprising a first lens, a second lens, a third and a fourth lens, wherein said first lens is a positive meniscus lens with its convex surface positioned on the object side, said second lens is a cemented positive meniscus doublet lens with its convex surface positioned on the object side, said third lens is a negative meniscus lens with its convex surface positioned on the object side and said fourth lens is a cemented positive doublet lens, and said largeaperture telephoto lens system satisfying the following conditions: Nu 2 > Nu 3 > 45, n3 > n2, 0.3f > r4 > 0.15f (1) Nu 6 > Nu 5 > 45, n5 > n6, 0.3f > r9 > 0.15f (2)30 > Nu 4, n4 > 1.70 (3)f123 > OR = 2f (4) where reference symbols n2, n3, n5, n6 and n4, respectively represent refractive indexes of the front and rear lenses of the cemented second and fourth lenses and refractive index of the third lens, reference symbols Nu 2, Nu 3, Nu 4, Nu 5, and Nu 6, respectively, represent Abbe''s numbers of said lenses, reference symbols r4 and r9, respectively, represent radii of curvatures of cemented surfaces of said second and fourth lenses, reference symbol f123 represents the total focal length of said first, second and third lenses and reference symbol f represents the total focal length of the lens system as a whole.
Claim 3
Dependent Claim
33 words
A large-aperture telephoto lens system according to claim 1 wherein said fourth lens is arranged to be moved in close-up photographing at the same time as advancing said lens system as a whole.
Claim 4
Dependent Claim
94 words
A large-aperture telephoto lens system comprising a first lens, a second lens, a third and a fourth lens, wherein said first lens is a positive meniscus lens with its convex surface positioned on the object side, said second lens is a cemented positive meniscus doublet lens with its convex surface positioned on the object side, said third lens is a negative meniscus lens with its convex surface positioned on the object side and said fourth lens is a cemented positive doublet lens, and said large-aperture telephoto lens system having numerical data as given below:
Claim 5
Dependent Claim
94 words
A large-aperture telephoto lens system comprising a first lens, a second lens, a third and a fourth lens, wherein said first lens is a positive meniscus lens with its convex surface positioned on the object side, said second lens is a cemented positive meniscus doublet lens with its convex surface positioned on the object side, said third lens is a negative meniscus lens with its convex surface positioned on the object side and said fourth lens is a cemented positive doublet lens, and said large-aperture telephoto lens system having numerical data as given below:
Claim 6
Dependent Claim
33 words
A large-aperture telephoto lens system according to claim 3 wherein said fourth lens is arranged to be moved in close-up photographing at the same time as advancing said lens system as a whole.
Claim 7
Dependent Claim
94 words
A large-aperture telephoto lens system comprising a first lens, a second lens, a third and a fourth lens, wherein said first lens is a positive meniscus lens with its convex surface positioned on the object side, said second lens is a cemented positive meniscus doublet lens with its convex surface positioned on the object side, said third lens is a negative meniscus lens with its convex surface positioned on the object side and said fourth lens is a cemented positive doublet lens, and said large-aperture telephoto lens system having numerical data as given below:
Claim 8
Dependent Claim
94 words
A large-aperture telephoto lens system comprising a first lens, a second lens, a third and a fourth lens, wherein said first lens is a positive meniscus lens with its convex surface positioned on the object side, said second lens is a cemented positive meniscus doublet lens with its convex surface positioned on the object side, said third lens is a negative meniscus lens with its convex surface positioned on the object side and said fourth lens is a cemented positive doublet lens, and said large-aperture telephoto lens system having numerical data as given below:
Claim 9
Dependent Claim
33 words
A large-aperture telephoto lens system according to claim 5 wherein said fourth lens is arranged to be moved in close-up photographing at the same time as advancing said lens system as a whole.
References Cited (Backward Citations)
US1463132A
Cited
US2481688A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-18 | 1978-05-20 | 1978-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-18 | 1982-05-20 | 1982-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-18 | 1986-05-20 | 1986-11-19 | $7700.00 | Window Closed / Lapsed |