Patent US4444472A successfully refreshed from Google Patents.
US4444472A
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Lens system having color separation optics
Assignee: Canon Inc
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Filing: 1980-08-05
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Granted: 1984-04-24
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Expires: 2000-08-05
Abstract
Abstract A lens system, particularly a zoom lens for color television camera is provided between the final face thereof and the image plane with a color separation optical system for example color separation prisms or a stripe filter, and is so constructed that the principal ray of each light beam entering said color separation optical system is always parallel to the optical axis, whereby all the beams are introduced into the color separation optical system under the same condition to maintain satisfactory color reproduction and polarizing characteristics.
Inventors
- 👤 Kazuo Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:10
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/10; G02B27/1006; G02B27/1013; G02B13/00; G02B15/00; G02B15/14; G02B15/142; G02B15/1425; G02B27/14; G02B27/145; H; H04; H04N; H04N23/00; H04N23/10; H04N23/13; H04N23/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
122 words
A lens system having a color separation optical system, comprising in the order from the object field side: a first lens group having focusing means and variable magnification lens means; a diaphragm for limiting a light beam from said first lens group; a second lens group being constantly placed at a fixed position, and forming the exit pupil at a substantially infinite distance position from the image plane of said lens system; and a color separation optical system disposed between said second lens group and the image plane, said diaphragm and said second lens group further being arranged to cause the principal rays of the light beam emerging from said second lens group to enter said color separation optical system in parallel.
Claim 2
Dependent Claim
122 words
A lens system having a color separation optical system, comprising in the order from the object field side: a first lens group having focusing means and variable magnification lens means; a diaphragm for limiting a light beam from said first lens group; a second lens group being constantly placed at a fixed position, and forming the exit pupil at a substantially infinite distance position from the image plane of said lens system; and a color separation optical system disposed between said second lens group and the image plane, said diaphragm and said second lens group further being arranged to cause the principal rays of the light beam emerging from said second lens group to enter said color separation optical system in parallel.
Claim 3
Dependent Claim
72 words
A lens having a color separation optical system according to the claim 1, wherein said second lens group is composed of a front lens group having a negative refractive power and a rear lens group having a positive refractive power which are arranged in this order in the image field side and each of which is provided with at least one combined lens composed of a concave lens and a convex lens.
Claim 4
Dependent Claim
59 words
A lens having a color separation optical system according to the claim 1, wherein said focusing means comprises a focusing lens group movable for focusing and wherein said variable magnification lens means comprises a zooming lens group movable for zooming, said focusing lens group and said zooming lens group being arranged in this order from the object field side.
Claim 5
Dependent Claim
125 words
A zoom lens having a color separation optical system, comprising: a first lens group including focusing means and zooming means in order from the object field side; a diaphragm for limiting a light beam from said first lens group; a second lens group for receiving the light beam from said diaphragm and for making the principal rays of the light beam emerging therefrom parallel to the optical axis of the lens; and a color separation optical system disposed between said second lens group and the image plane of said zooming means, said diaphragm and said second lens group further being arranged to cause the principal rays of the light beam emerging from said second lens group to enter said color separation optical system in parallel.
Claim 6
Dependent Claim
125 words
A zoom lens having a color separation optical system, comprising: a first lens group including focusing means and zooming means in order from the object field side; a diaphragm for limiting a light beam from said first lens group; a second lens group for receiving the light beam from said diaphragm and for making the principal rays of the light beam emerging therefrom parallel to the optical axis of the lens; and a color separation optical system disposed between said second lens group and the image plane of said zooming means, said diaphragm and said second lens group further being arranged to cause the principal rays of the light beam emerging from said second lens group to enter said color separation optical system in parallel.
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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) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |