Patent US4571033A successfully refreshed from Google Patents.
US4571033A
Expired / Lapsed
US
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Zoom lens
Assignee: Canon Inc
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Filing: 1984-02-22
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Granted: 1986-02-18
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Expires: 2004-02-22
Abstract
Abstract A zoom lens comprising, from front to rear, a positive first lens component, a negative second lens component, a positive third lens component and an image forming or fourth lens component, wherein as zooming occurs from the wide angle to the telephoto position, the first and third lens components are moved axially forward, while the second lens component is held stationary. By giving appropriately specified ranges for numerical values of the focal lengths of the first to third lens components, improvements in the compactness are achieved while still permitting good correction of aberrations.
Inventors
- 👤 Masatake Kato
- 👤 Nozomu Kitagishi
- 👤 Jun Hattori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:40
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/144; G02B15/1441
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
130 words
A zoom lens comprising: a first lens component of positive refractive power, a second lens component of negative refractive power, a third lens component of positive refractive power and a fourth lens component for forming an image, in the order from the front, zooming being performed by moving said first lens component and said third lens component while said second lens component being held stationary, wherein when zoomed to the telephoto position, each of said first and said third lens components lies in more front a position than when in the wide angle position, and satisfying the following conditions ##EQU3## wherein fI, fII and fIII denote the focal lengths of said first, said second and said third lens components respectively, and fT the longest focal length of the entire system.
Claim 2
Dependent Claim
130 words
A zoom lens comprising: a first lens component of positive refractive power, a second lens component of negative refractive power, a third lens component of positive refractive power and a fourth lens component for forming an image, in the order from the front, zooming being performed by moving said first lens component and said third lens component while said second lens component being held stationary, wherein when zoomed to the telephoto position, each of said first and said third lens components lies in more front a position than when in the wide angle position, and satisfying the following conditions ##EQU3## wherein fI, fII and fIII denote the focal lengths of said first, said second and said third lens components respectively, and fT the longest focal length of the entire system.
Claim 3
Dependent Claim
38 words
A zoom lens according to claim 1, further comprising a diaphragm arranged in a space between said second lens component and said third lens component, said diaphragm moving together with said first lens component when zooming is performed.
References Cited (Backward Citations)
US4232942A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-17 | 1989-08-19 | 1990-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-17 | 1993-08-19 | 1994-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-17 | 1997-08-19 | 1998-02-18 | $7700.00 | Window Closed / Lapsed |