US3566130A
Expired / Lapsed
US
⏱️ 0.0 years remaining
By addition of a spatially invariant modulation to spatially varying modulation representature of an image
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1969-05-15
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Granted: 1971-02-23
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Expires: 1989-05-15
Abstract
Abstract Apparatus is disclosed for varying the contrast of an image by exposing a photoconductive medium associated with an electrooptic medium to the image to vary the conductivity of the photoconductive medium and the intensity of an electric field associated with the mediums in a pattern representative of the image, uniformly modulating radiation subject to modulation by an electro-optic characteristic of the electro-optic medium in a pattern representative of the image, detecting the modulation of the radiation, and producing a radiation pattern representative of the image with modified contrast.
Inventors
- 👤 Ralph Edward Aldrich
- 👤 Paul John Caruso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:36
CPC Classifications
G; G03; G03D; G03D15/00; G03D15/006; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G03B; G03B27/00; G03B27/72; G03B27/725; G03B7/00; G03B7/28
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
105 words
Apparatus for varying the contrast of an image comprising: an electro-optic medium having a characteristic which varies as a function of the intensity of an associated electric field; means for providing at said electro-optic medium an electric field whose intensity varies as a function of an image whose contrast is to be modified; means for uniformly modulating radiation subject to modulation by said characteristic of said electro-optic medium for changing the differences in intensity between points of different intensity of the image; and means for detecting the modulation imposed on the radiation, and producing a pattern of radiation representative of said image with contrast modified.
Claim 2
Dependent Claim
105 words
Apparatus for varying the contrast of an image comprising: an electro-optic medium having a characteristic which varies as a function of the intensity of an associated electric field; means for providing at said electro-optic medium an electric field whose intensity varies as a function of an image whose contrast is to be modified; means for uniformly modulating radiation subject to modulation by said characteristic of said electro-optic medium for changing the differences in intensity between points of different intensity of the image; and means for detecting the modulation imposed on the radiation, and producing a pattern of radiation representative of said image with contrast modified.
Claim 3
Dependent Claim
98 words
The apparatus of claim 1 in which said means for providing includes: a photoconductive medium, associated with said electro-optic medium, whose conductivity varies as a function of the intensity of an image incident on it; first means for exposing said photoconductive medium to an image to vary the conductivity of said photoconductive medium in a pattern representative of the intensity pattern of said image; and means for applying, across said photoconductive medium and said electro-optic medium, an electric field whose intensity varies at said electro-optic medium in a pattern representative of the conductivity pattern of said photoconductive medium.
Claim 4
Dependent Claim
25 words
The apparatus of claim 2 in which said means for uniformly modulating includes means for electro-optically modulating radiation subject to modulation by said electro-optic medium.
Claim 5
Dependent Claim
25 words
The apparatus of claim 2 in which said means for uniformly modulating includes means for optically modulating radiation subject to modulation by said electro-optic medium.
Claim 6
Dependent Claim
27 words
The apparatus of claim 3 in which said means for electro-optically modulating includes means for controlling the intensity of the electric field established Across said electro-optic medium.
Claim 7
Dependent Claim
50 words
The apparatus of claim 3 in which said means for electro-optically modulating includes a second electro-optic medium having the same said characteristic, second means for applying an electric field across said second electro-optic medium and second means for controlling the intensity of the electric field across said second electro-optic medium.
Claim 8
Dependent Claim
18 words
The apparatus of claim 2 in which said mediums are contained in separate materials arranged as adjacent layers.
Claim 9
Dependent Claim
28 words
The apparatus of claim 2 in which said means for applying includes a pair of electrodes connectable to a voltage source and arranged with said mediums between them.
Claim 10
Dependent Claim
17 words
The apparatus of claim 2 in which said characteristic of said electro-optic medium is electrically induced birefringence.
Claim 11
Dependent Claim
15 words
The apparatus of claim 2 in which said first means for exposing includes polarizing means.
Claim 12
Dependent Claim
14 words
The apparatus of claim 10 in which said polarizing means includes a plane polarizer.
Claim 13
Dependent Claim
16 words
The apparatus of claim 9 in which said means for detecting and producing includes an analyzer.
Claim 14
Dependent Claim
13 words
The apparatus of claim 12 in which said analyzer is a plane polarizer.
Claim 15
Dependent Claim
16 words
The apparatus of claim 13 in which said plane polarizer is oriented as a crossed polarizer.
Claim 16
Dependent Claim
26 words
The apparatus of claim 9 in which said means for uniformly modulating includes means for controlling the intensity of the electric field across said electro-optic medium.
Claim 17
Dependent Claim
48 words
The apparatus of claim 9 in which said means for uniformly modulating includes a second electro-optic medium which exhibits electrically induced birefringence, second means for applying a second electric field across said second electro-optic medium, and second means for controlling the electric field across said second electro-optic medium.
Claim 18
Dependent Claim
26 words
The apparatus of claim 12 in which said means for uniformly modulating includes means for providing relative rotational motion between said analyzer and said electro-optic medium.
Claim 19
Dependent Claim
35 words
The apparatus of claim 12 in which said means for uniformly modulating includes an optical retardation element and means for providing rotational relative motion between said analyzer and electro-optic medium and said optical retardation element.
Claim 20
Dependent Claim
15 words
The apparatus of claim 18 in which said optical retardation element is a half-wave plate.
Claim 21
Dependent Claim
20 words
The apparatus of claim 2 in which said photoconductive and said electro-optic mediums transmit the radiation which forms said image.
Claim 22
Dependent Claim
31 words
The apparatus of claim 2 in which said means for detecting and producing includes a radiation source and second means for exposing said electro-optic medium to radiation from said radiation source.
Claim 23
Dependent Claim
13 words
The apparatus of claim 21 in which said radiation source provides polarized radiation.
Claim 24
Dependent Claim
14 words
The apparatus of claim 22 in which said radiation source provides plane polarized radiation.
Claim 25
Dependent Claim
33 words
The apparatus of claim 21 in which said second means for exposing includes means for simultaneously directing said image to said photoconductive medium and radiation from said radiation source to said electro-optic medium.
Claim 26
Dependent Claim
39 words
The apparatus of claim 21 in which said means for simultaneously directing includes beam joining means for projecting said image to said photoconductive medium and said radiation from said radiation source through said photoconductive medium to said electro-optic medium.
Claim 27
Dependent Claim
31 words
The apparatus of claim 2 in which said means for uniformly modulating includes means for reversing the modulation of said radiation subject to modulation by said characteristic of said electro-optic medium.
Claim 28
Dependent Claim
24 words
The apparatus of claim 26 in which said means for reversing the modulation includes means for reversing the electric field across said electro-optic medium.
Claim 29
Dependent Claim
17 words
The apparatus of claim 27 in which said means for reversing the electric field includes switch means.
Claim 30
Dependent Claim
22 words
The apparatus of claim 26 in which said means for reversing the modulation includes means for reversing the retardation of said radiation.
Claim 31
Independent Claim
131 words
A method of vArying the contrast of an image comprising: providing at an electro-optic medium, having a characteristic that varies as a function of an associated electric field, an electric field whose intensity varies as a function of an image whose contrast is to be modified; exposing to said image a photoconductive medium whose conductivity varies as a function of the intensity of an image incident on it to vary the conductivity of said photoconductive medium and the intensity of an electric field associated with said photoconductive medium and an associated electro-optic medium in a pattern representative of said image; uniformly modulating radiation subject to modulation by said electro-optic medium; and detecting the modulation imposed on the radiation and producing a pattern of radiation representative of said image with contrast modified.
Claim 32
Independent Claim
131 words
A method of vArying the contrast of an image comprising: providing at an electro-optic medium, having a characteristic that varies as a function of an associated electric field, an electric field whose intensity varies as a function of an image whose contrast is to be modified; exposing to said image a photoconductive medium whose conductivity varies as a function of the intensity of an image incident on it to vary the conductivity of said photoconductive medium and the intensity of an electric field associated with said photoconductive medium and an associated electro-optic medium in a pattern representative of said image; uniformly modulating radiation subject to modulation by said electro-optic medium; and detecting the modulation imposed on the radiation and producing a pattern of radiation representative of said image with contrast modified.
References Cited (Backward Citations)
US3499157A
Cited
US3449583A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |