US4172635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom lens system
Assignee: Minolta Co Ltd
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Filing: 1978-07-19
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Granted: 1979-10-30
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Expires: 1998-07-19
Abstract
Abstract A wide angle zoom lens system having a front lens group of a positive refractive power with an extended zoom ratio. A second lens group is located adjacent the first lens group and has sufficient negative refractive power so that the combined refractive power of the first and second lens group is negative. The first and second lens groups are movable as a fixed unit for a zooming operation in a first zoom range defined between the shortest focal length and a medium focal length. These same lens groups are separable for a zooming operation in a second zoom range between the medium focal length and the longest focal length.
Inventors
- 👤 Shuji Ogino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:48
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/143; G02B15/1431; G02B15/143105
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
152 words
A wide angle zoom lens system comprising: a first front lens group of a positive refractive power; a second lens group located next to the first front lens group at the image side thereof, the second lens group having a negative refractive power of such magnitude relative to the positive refractive power of the first front lens group that the combined refractive power of the first and second lens groups is negative; and a plurality of lens elements located at the image side of the second lens group to provide as a whole a positive refractive power, where the first and second lens groups are movable as a fixed unit for a zooming operation in a first zoom range defined between the shortest focal length and a medium focal length and are separable from each other in a second zoom range defined between the medium focal length and the longest focal length.
Claim 2
Dependent Claim
152 words
A wide angle zoom lens system comprising: a first front lens group of a positive refractive power; a second lens group located next to the first front lens group at the image side thereof, the second lens group having a negative refractive power of such magnitude relative to the positive refractive power of the first front lens group that the combined refractive power of the first and second lens groups is negative; and a plurality of lens elements located at the image side of the second lens group to provide as a whole a positive refractive power, where the first and second lens groups are movable as a fixed unit for a zooming operation in a first zoom range defined between the shortest focal length and a medium focal length and are separable from each other in a second zoom range defined between the medium focal length and the longest focal length.
Claim 3
Dependent Claim
47 words
A zoom lens system as in claim 1, wherein the first and second lens groups are shiftable in a fixed relationship for a focusing operation in the first zoom range while only the first lens group is shiftable for a focusing operation in the second zoom range.
Claim 4
Dependent Claim
66 words
A zoom lens system as in claim 1 wherein the plurality of lens elements form a third lens group of a positive refractive power and the airspace between the second and third lens groups is variable in the first zoom range during a zooming operation while the airspace between the first and second lens groups is variable in the second zoom range for a zooming operation.
Claim 5
Dependent Claim
84 words
A zoom lens system as in claim 3, wherein the first and second lens groups are shiftable in a fixed relationship and the third lens group is also shiftable with varying the airspace between the second and third lens groups for a zooming operation in the first zoom range, the first and second lens groups being shiftable with varying the airspace between the first and second lens groups while the third lens group remains stationary for a zooming operation in the second zoom range.
References Cited (Backward Citations)
US3074317A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-29 | 1983-04-30 | 1983-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-29 | 1987-04-30 | 1987-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-29 | 1991-04-30 | 1991-10-30 | $7700.00 | Window Closed / Lapsed |