US4380376A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom objective
Assignee: Canon Inc
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Filing: 1980-06-16
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Granted: 1983-04-19
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Expires: 2000-06-16
Abstract
Abstract A zoom objective is composed of three components of which the first and the third each perform a one-round axial movement over the range of variation, while the second simultaneously performs a monotonic axial movement in one direction.
Inventors
- 👤 Shigeyuki Suda
- 👤 Kazuo Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:33
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/143; G02B15/1431; G02B15/143105
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
116 words
A zoom objective comprising: a first lens group, a second lens group and a third lens group arranged in the order mentioned from an objective end to an image end; said first lens group having a positive refractive power and being axially movable forward and then rearward when zooming from a wide angle to a telephoto setting; said second lens group having a negative refractive power and being axially movable from the objective end to the image end when zooming from the wide angle to the telephoto setting; and said third lens group having a positive refractive power and being axially movable forward and then rearward when zooming from the wide angle to the telephoto setting.
Claim 2
Dependent Claim
116 words
A zoom objective comprising: a first lens group, a second lens group and a third lens group arranged in the order mentioned from an objective end to an image end; said first lens group having a positive refractive power and being axially movable forward and then rearward when zooming from a wide angle to a telephoto setting; said second lens group having a negative refractive power and being axially movable from the objective end to the image end when zooming from the wide angle to the telephoto setting; and said third lens group having a positive refractive power and being axially movable forward and then rearward when zooming from the wide angle to the telephoto setting.
Claim 3
Dependent Claim
35 words
A zoom objective as described in claim 1, wherein the locus of movement of said first lens group and the locus of movement of said third lens group are non-parallel to each other during zooming.
Claim 4
Dependent Claim
143 words
A zoom objective comprising: a first lens group, a second lens group, and a third lens group arranged in the order mentioned from an objective end to an image end; said first lens group having a positive refractive power and focusing and compensating functions, and moving first toward the objective end and then toward the image end during zooming from a wide angle position to a tele position; said second lens group having a negative refractive power and magnificating function, and moving only in one direction from the objective end to the image end during zooming from the wide angle position to the tele position; and said third lens group having a positive refractive power and compensating function, and moving first toward the objective end and then to the image surface end during zooming from the wide angle position to the tele position.
Claim 5
Dependent Claim
143 words
A zoom objective comprising: a first lens group, a second lens group, and a third lens group arranged in the order mentioned from an objective end to an image end; said first lens group having a positive refractive power and focusing and compensating functions, and moving first toward the objective end and then toward the image end during zooming from a wide angle position to a tele position; said second lens group having a negative refractive power and magnificating function, and moving only in one direction from the objective end to the image end during zooming from the wide angle position to the tele position; and said third lens group having a positive refractive power and compensating function, and moving first toward the objective end and then to the image surface end during zooming from the wide angle position to the tele position.
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) | 1986-04-18 | 1986-10-18 | 1987-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-18 | 1990-10-18 | 1991-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-18 | 1994-10-18 | 1995-04-19 | $7700.00 | Window Closed / Lapsed |