US5357374A
Expired / Lapsed
US
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Zoom lens system
Assignee: Fujinon Corp
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Filing: 1993-05-12
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Granted: 1994-10-18
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Expires: 2013-05-12
Abstract
Abstract A zoom lens system consisting of three groups, wherein intervals between the groups are varied to thereby change a focal length. In this zoom lens system, the number of lenses constituting the groups is one, respectively. That is, a first group is constituted by a convex meniscus lens 11, a second group is constituted by a negative meniscus lens 12 directing a strong positive surface thereof toward an object and a third group is constituted by a negative meniscus lens 13 directing a strong convex surface thereof toward the object, whereby the number of the constituting lenses can be minimized to be three, and, because of the zoom lens system consisting of the three groups, the movement of the lens is scattered, so that the movement value of the lens for obtaining a desirable zooming ratio can be decreased.
Inventors
- 👤 Kazunori Ohno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:13
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/143; G02B15/1435; G02B15/143503
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
69 words
A zoom lens system consisting of three groups, wherein intervals between the groups are varied to change a focal length, characterized in that: a first group consists of a negative lens; a second group consists of a positive meniscus lens directing a strong convex surface thereof toward an object; and a third group consists of a negative meniscus lens, which directs a strong convex surface thereof toward the object.
Claim 2
Dependent Claim
69 words
A zoom lens system consisting of three groups, wherein intervals between the groups are varied to change a focal length, characterized in that: a first group consists of a negative lens; a second group consists of a positive meniscus lens directing a strong convex surface thereof toward an object; and a third group consists of a negative meniscus lens, which directs a strong convex surface thereof toward the object.
Claim 3
Dependent Claim
50 words
The zoom lens system as set forth in claim 1, wherein, when a focal length of said second group is f 2 ' and a composite focal length of the whole system on the wide side is f w ', the following formula is to be satisfied: 0.5<f.sub.2 '/f.sub.w '<0.8.
Claim 4
Dependent Claim
27 words
The zoom lens system as set forth in claim 1, wherein all of said lenses have at least one surface thereof formed to provide an aspherical shape.
Claim 5
Dependent Claim
20 words
The zoom lens system as set forth in claim 1, wherein all of said lenses are formed of plastic lenses.
Claim 6
Dependent Claim
50 words
The zoom lens system as set forth in claim 1, wherein, when a focal length of said third group is f 3 ' and a composite focal length of the whole system on the wide side is f w ', the following formula is to be satisfied: -0.05<f.sub.w '∠f.sub.3 '<0.9.
Claim 7
Dependent Claim
69 words
A zoom lens system consisting of three groups, wherein intervals between the groups are varied to change a focal length, characterized in that: a first group consists of a negative lens; a second group consists of a positive meniscus lens directing a strong convex surface thereof toward an object; and a third group consists of a positive meniscus lens, which directs a strong convex surface thereof toward the object.
Claim 8
Dependent Claim
69 words
A zoom lens system consisting of three groups, wherein intervals between the groups are varied to change a focal length, characterized in that: a first group consists of a negative lens; a second group consists of a positive meniscus lens directing a strong convex surface thereof toward an object; and a third group consists of a positive meniscus lens, which directs a strong convex surface thereof toward the object.
Claim 9
Dependent Claim
50 words
The zoom lens system as set forth in claim 6, wherein, when a focal length of said second group is f 2 ' and a composite focal length of the whole system on the wide side is f w ', the following formula is to be satisfied: 0.5<f.sub.2 '/f.sub.w '<0.8.
Claim 10
Dependent Claim
27 words
The zoom lens system as set forth in claim 6, wherein all of said lenses have at least one surface thereof formed to provide an aspherical shape.
Claim 11
Dependent Claim
20 words
The zoom lens system as set forth in claim 6, wherein all of said lenses are formed of plastic lenses.
Claim 12
Dependent Claim
50 words
The zoom lens system as set forth in claim 6, wherein, when a focal length of said third group is f 3 ' and a composite focal length of the whole system on the wide side is f w ', the following formula is to be satisfied: -0.05<f.sub.w '/f.sub.3 '<0.9.
References Cited (Backward Citations)
US4733952A
Cited
US4824223A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-17 | 1998-04-18 | 1998-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-17 | 2002-04-18 | 2002-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-17 | 2006-04-18 | 2006-10-18 | $7700.00 | Window Closed / Lapsed |