US5097360A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom lens capable of changing a range of variable focal length
Assignee: Canon Inc
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Filing: 1991-08-05
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Granted: 1992-03-17
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Expires: 2011-08-05
Abstract
Abstract A zoom lens capable of changing the range of variable focal length to another limit, comprising, from front to rear, a zoom section including a variator and a compensator arranged upon zooming movement to vary the focal length in a predetermined range, a diaphragm, and a relay lens section receptive of the afocal light beam from the zoom section to form an image and having a front lens unit and a rear lens unit, the front lens unit being provided with a fixed sub-unit and an interchangeable sub-unit in this order from the front, wherein the interchangeable sub-unit is removed to create a space between the fixed sub-unit and the rear lens unit, into which a range changing lens unit is then inserted, so that the range of variable focal length is changed.
Inventors
- 👤 Kiyoshi Fukami
- 👤 Jun Hosoya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:06
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/142; G02B15/1421
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
211 words
A zoom lens capable of changing the range of variable focal length, comprising: a zoom section having positive refractive powers that are independent of zooming, and a plurality of movable lens units arranged to axially move to affect zooming in a predetermined range of variable focal length; a stop arranged on the image surface side of said zoom section to determine an F-number of said zoom lens; a relay lens section arranged on the image surface side of said stop to form an image with a light beam emerging from said zoom section and having a front lens unit and a rear lens unit, said front lens unit of said relay lens section being provided with a fixed sub-unit having a negative refractive power and a detachably mounted sub-unit; a range changing lens unit so arranged that when said detachably mounted sub-unit is detached to change the range of variable focal length, said range changing lens unit is attached in a space between said fixed sub-unit and said rear lens unit; wherein the minimum spacing between the last movable lens unit of said zoom section and said fixed sub-unit is larger than the spacing between said fixed sub-unit and said detachably mounted sub-unit; and the zoom lens satisfies the following condition:
Claim 2
Dependent Claim
211 words
A zoom lens capable of changing the range of variable focal length, comprising: a zoom section having positive refractive powers that are independent of zooming, and a plurality of movable lens units arranged to axially move to affect zooming in a predetermined range of variable focal length; a stop arranged on the image surface side of said zoom section to determine an F-number of said zoom lens; a relay lens section arranged on the image surface side of said stop to form an image with a light beam emerging from said zoom section and having a front lens unit and a rear lens unit, said front lens unit of said relay lens section being provided with a fixed sub-unit having a negative refractive power and a detachably mounted sub-unit; a range changing lens unit so arranged that when said detachably mounted sub-unit is detached to change the range of variable focal length, said range changing lens unit is attached in a space between said fixed sub-unit and said rear lens unit; wherein the minimum spacing between the last movable lens unit of said zoom section and said fixed sub-unit is larger than the spacing between said fixed sub-unit and said detachably mounted sub-unit; and the zoom lens satisfies the following condition:
Claim 3
Dependent Claim
56 words
-1. 6≦fRFF/(fZ-EZ)≦-0.4 where fRFF is a focal length of said fixed sub-unit, fZ is a focal length of said zoom section in any desired zooming position when focusing on an infinitely distant object, and EZ is an interval between a rear principal point of said zoom section and a front principal point of said fixed sub-unit.
Claim 4
Dependent Claim
56 words
-1. 6≦fRFF/(fZ-EZ)≦-0.4 where fRFF is a focal length of said fixed sub-unit, fZ is a focal length of said zoom section in any desired zooming position when focusing on an infinitely distant object, and EZ is an interval between a rear principal point of said zoom section and a front principal point of said fixed sub-unit.
Claim 5
Dependent Claim
17 words
A zoom lens according to claim 1, wherein said range changing lens unit is a telephoto system.
Claim 6
Dependent Claim
180 words
A zoom lens capable of changing the range of variable focal length, comprising: a zoom section having a plurality of movable lens units arranged to axially move to affect zooming in a predetermined range of variable focal length; a stop arranged on the image surface side of said zoom section to determine an F-number of said zoom lens; a relay lens section arranged on the image surface side of said stop to form an image with a light beam emerging from said zoom section and having a front lens unit and a rear lens unit, said front lens unit of said relay lens section being provided with a fixed sub-unit and a detachably mounted sub-unit; a range changing lens unit so arranged that when said detachably mounted sub-unit is detached to change the range of variable focal length, said range changing lens unit is attached in a space between said fixed sub-unit and said rear lens unit; and wherein said zoom section has always positive composite refractive powers independent of zooming, and said fixed sub-unit has a negative refractive power.
Claim 7
Dependent Claim
180 words
A zoom lens capable of changing the range of variable focal length, comprising: a zoom section having a plurality of movable lens units arranged to axially move to affect zooming in a predetermined range of variable focal length; a stop arranged on the image surface side of said zoom section to determine an F-number of said zoom lens; a relay lens section arranged on the image surface side of said stop to form an image with a light beam emerging from said zoom section and having a front lens unit and a rear lens unit, said front lens unit of said relay lens section being provided with a fixed sub-unit and a detachably mounted sub-unit; a range changing lens unit so arranged that when said detachably mounted sub-unit is detached to change the range of variable focal length, said range changing lens unit is attached in a space between said fixed sub-unit and said rear lens unit; and wherein said zoom section has always positive composite refractive powers independent of zooming, and said fixed sub-unit has a negative refractive power.
Claim 8
Dependent Claim
66 words
A zoom lens according to claim 3, satisfying the following condition: -1.6≦fRFF/(fZ-EZ)≦0.4 where fRFF is a focal length of said fixed sub-unit, fZ is a focal length of said zoom section in any desired zooming position when focusing on an infinitely distant object, and EZ is an interval between a rear principal point of said zoom section and a front principal point of said fixed sub-unit.
Claim 9
Dependent Claim
187 words
A zoom lens capable of changing the range of variable focal length, comprising: a zoom section having a plurality of movable lens units arranged to axially move to affect zooming in a predetermined range of variable focal length; a stop arranged on the image surface side of said zoom section to determine an F-number of said zoom lens; a relay lens section arranged on the image surface side of said stop to form an image with a light beam emerging from said zoom section and having a front lens unit and a rear lens unit, said front lens unit of said relay lens section being provided with a fixed sub-unit and a detachably mounted sub-unit; a range changing lens unit so arranged that when said detachably mounted sub-unit is detached to change the range of variable focal length, said range changing lens unit is attached in a space between said fixed sub-unit and said rear lens unit; wherein said zoom section has always negative composite refractive powers independent of zooming and said fixed sub-unit has a positive refractive power; and said zoom lens satisfies the following condition:
Claim 10
Dependent Claim
187 words
A zoom lens capable of changing the range of variable focal length, comprising: a zoom section having a plurality of movable lens units arranged to axially move to affect zooming in a predetermined range of variable focal length; a stop arranged on the image surface side of said zoom section to determine an F-number of said zoom lens; a relay lens section arranged on the image surface side of said stop to form an image with a light beam emerging from said zoom section and having a front lens unit and a rear lens unit, said front lens unit of said relay lens section being provided with a fixed sub-unit and a detachably mounted sub-unit; a range changing lens unit so arranged that when said detachably mounted sub-unit is detached to change the range of variable focal length, said range changing lens unit is attached in a space between said fixed sub-unit and said rear lens unit; wherein said zoom section has always negative composite refractive powers independent of zooming and said fixed sub-unit has a positive refractive power; and said zoom lens satisfies the following condition:
Claim 11
Dependent Claim
56 words
-2. 0≦fRFF/(fZ-EZ)≦-0.6 where fRFF is a focal length of said fixed sub-unit, fZ is a focal length of said zoom section in any desired zooming position when focusing on an infinitely distant object, and EZ is an interval between a rear principal point of said zoom section and a front principal point of said fixed sub-unit.
Claim 12
Dependent Claim
56 words
-2. 0≦fRFF/(fZ-EZ)≦-0.6 where fRFF is a focal length of said fixed sub-unit, fZ is a focal length of said zoom section in any desired zooming position when focusing on an infinitely distant object, and EZ is an interval between a rear principal point of said zoom section and a front principal point of said fixed sub-unit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-17 | 1995-09-16 | 1996-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-17 | 1999-09-16 | 2000-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-17 | 2003-09-16 | 2004-03-17 | $7700.00 | Window Closed / Lapsed |