US4445774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Document imaging system with improved exposure uniformity at image plane
Assignee: Xerox Corp
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Filing: 1982-04-30
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Granted: 1984-05-01
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Expires: 2002-04-30
Abstract
Abstract The invention discloses the use of a corrector element placed in an imaging system to selectively vignette energy emanating from the exit pupil of a lens as a function of the field angle of the lens. Several imaging systems are disclosed which illustrate the technique used in determining optimum design and location of the corrector elements.
Inventors
- 👤 Richard A. Spinelli
- 👤 Edwin F. Glab
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 00:38
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/32; G03B27/52; G03B27/522; G03B27/525; G03B27/526
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
104 words
An imaging system for projecting an image of a document lying in an object plane onto a photosensitive image plane, said system including: a projection lens; means for illuminating said document during an exposure mode of operation and for directing images of said document along an optical axis towards the entrance pupil of said lens; and at least one uniformly opaque illumination corrector positioned between said object and image planes and within the field of view of said lens, said corrector adapted to selectively vignette energy emanating from said field of view so as to provide a uniform exposure level at the image plane.
Claim 2
Dependent Claim
104 words
An imaging system for projecting an image of a document lying in an object plane onto a photosensitive image plane, said system including: a projection lens; means for illuminating said document during an exposure mode of operation and for directing images of said document along an optical axis towards the entrance pupil of said lens; and at least one uniformly opaque illumination corrector positioned between said object and image planes and within the field of view of said lens, said corrector adapted to selectively vignette energy emanating from said field of view so as to provide a uniform exposure level at the image plane.
Claim 3
Dependent Claim
16 words
The imaging system of claim 1 wherein the corrector is centrally located along said optical axis.
Claim 4
Dependent Claim
20 words
The imaging system of claim 1 or 2 wherein the corrector is placed on the image side of said lens.
Claim 5
Dependent Claim
19 words
The imaging system of claim 1 or 2 wherein the corrector is placed in a plane within the lens.
Claim 6
Dependent Claim
20 words
The imaging system of claim 1 or 2 wherein the corrector is located on the outer surface of said lens.
Claim 7
Dependent Claim
16 words
The imaging system of claim 1 or 2 wherein the corrector has a radially symmetrical configuration.
References Cited (Backward Citations)
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Cited
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US3669538A
Cited
US3777135A
Cited
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Cited
US4298274A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-01 | 1987-10-31 | 1988-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-01 | 1991-10-31 | 1992-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-01 | 1995-10-31 | 1996-05-01 | $7700.00 | Window Closed / Lapsed |