US3574458A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for modifying contrast in photographic images
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1968-04-08
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Granted: 1971-04-13
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Expires: 1988-04-08
Abstract
Abstract Apparatus is disclosed for exposing a control material with radiation through an image-bearing transparency to vary the impedance of the control material in a pattern in proportion to the density of the image borne by the transparency. Applied across the control material and an electroluminescent material is an electric field which varies at the electroluminescent material as a function of the impedance pattern of the control material. And means are provided for exposing through the transparency a photosensitive medium with actinic radiation produced by the electroluminescent material whose intensity varies as a function of the electric field applied to it in a pattern proportional to the density distribution of the image borne by the transparency.
Inventors
- 👤 Hollis Edward French
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:49
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72; G03B27/727
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
51 words
The apparatus of claim 1 in which said first means for exposing includes a second source of radiant energy for exposing said control material through said transparency with radiation in a second frequency range to vary the impedance of said control material in direct proportion to the density of said transparency.
Claim 2
Dependent Claim
84 words
The apparatus of claim 1 in which said first means for exposing includes a second source of radiant energy for uniformly exposing said control material with radiation in a second frequency range to uniformly decrease the impedance of said control material, and a third source of radiant energy for exposing said control material, having uniformly decreased impedance, through said transparency with radiation in a third frequency range to vary the impedance of said control material in inverse proportion to the density of said transparency.
Claim 3
Dependent Claim
32 words
The apparatus of claim 1 in which said first means for exposing includes a radiation source and first support means for positioning said transparency between said control material and said radiation source.
Claim 4
Dependent Claim
76 words
The apparatus of claim 1 in which said means for applying an electric field includes: a first electrode connected to said control material and a second electrode connected to said electroluminescent material, said first electrode being transparent to radiation applied to said control material by said first means for exposing and said second electrode being transparent to radiation generated by said electroluminescent material; and a source of electrical energy for providing a voltage across said electrodes.
Claim 5
Dependent Claim
15 words
The apparatus of claim 5 in which said source of electrical energy provides alternating current.
Claim 6
Dependent Claim
17 words
The apparatus of claim 1 in which said electroluminescent material and said control material have an interface.
Claim 7
Dependent Claim
26 words
The apparatus of claim 1 in which said radiation in said first frequency range emitted by said electroluminescent material includes actinic light in the visible range.
Claim 8
Dependent Claim
17 words
The apparaTus of claim 2 in which said second frequency range includes radiation in the ultraviolet range.
Claim 9
Dependent Claim
34 words
The apparatus of claim 3 in which said radiation in said second frequency range includes radiation in the ultraviolet range and said radiation in the third frequency range includes radiation in the infrared range.
Claim 10
Dependent Claim
34 words
The apparatus of claim 1 in which said first means for exposing includes means for simultaneously exposing said control material to the entire pattern of radiation established by the image borne by said transparency.
Claim 11
Dependent Claim
30 words
The apparatus of claim 1 in which said first means for exposing said transparency and said control material are fixed relative to each other during exposure of said control material.
Claim 12
Dependent Claim
31 words
The apparatus of claim 1 in which said control material, said electroluminescent material, said transparency, and said photosensitive medium are fixed relative to each other during exposure of said photosensitive medium.
Claim 13
Dependent Claim
205 words
Apparatus for modifying the contrast of a photographic image during printing, comprising: a control material whose impedance decreases in proportion to the intensity of ultraviolet radiation applied to it; an ultraviolet radiation source; means for supporting an image-bearing transparency between said control material and said ultraviolet source to vary the impedance of said control material in direct proportion to the density distribution of the image borne by said transparency; an electroluminescent material for providing a source of actinic radiation whose intensity varies in direct proportion to the intensity of an applied electric field, said electroluminescent material having an interface with said control material; a first electrode connected to the external face of said control material, and a second electrode connected to the external face of said electroluminescent material; and a source of electric energy, connected in series with said first electrode, said control material, said electroluminescent material, and said second electrode, to produce at said electroluminescent material an electric field which varies in proportion to the impedance pattern of said control material, to expose said photosensitive medium through said transparency to said actinic radiation, produced by said electroluminescent material, whose intensity varies in proportion to the density distribution of the image borne by said transparency.
Claim 14
Dependent Claim
234 words
Apparatus for modifying the contrast of a photographic image during printing, comprising: a control material whose impedance decreases in proportion to the intensity of ultraviolet radiation applied to it and whose impedance, when so decreased, may be increased by application of infrared radiation; an ultraviolet radiation source for uniformly exposing said control material to uniformly decrease its impedance; an infrared radiation source; means for supporting an image-bearing transparency between said control material and said ultraviolet source to vary the impedance of said control material in direct proportion to the density distribution of the image borne by said transparency; an electroluminescent material for providing a source of actinic radiation whose intensity varies in direct proportion to the intensity of an applied electric field, said electroluminescent material having an interface with said control material; a first electrode connected to the external face of said control material, and a second electrode connected to the external face of said electroluminescent material; a source of electric energy, connected in series with said first electrode, said control material, said electroluminescent material, and said second electrode, to produce at said electroluminescent material an electric field which varies in proportion to the impedance pattern of said control material, to expose said photosensitive medium through said transparency to said actinic radiation, produced by a said electroluminescent material, whose intensity varies in Proportion to the density distribution of the image borne by said transparency.
Claim 15
Independent Claim
140 words
A method of modifying the contrast of a photographic image during printing comprising: exposing a control material, whose impedance varies in proportion to the intensity of applied radiation in particular frequency ranges, to radiation in a particular frequency range through an image-bearing transparency to vary the impedance of said control material in a pattern corresponding to the density distribution of the image borne by said transparency; applying, across said control material and an electroluminescent material, an electric field which varies, at the electroluminescent material, as a function of the impedance pattern of said control material; and exposing a photosensitive medium through said transparency to radiation in a first frequency range, emitted by said electroluminescent material when subject to an electric field, in a pattern whose intensity varies in proportion to the density distribution of the image borne by said transparency.
Claim 16
Dependent Claim
32 words
The method of claim 16 in which said control material is exposed with radiation in a second frequency range to vary its impedance in direct proportion to the density of said transparency.
Claim 17
Dependent Claim
65 words
The method of claim 16 further including uniformly exposing said control material with radiation in a second frequency range to uniformly decrease the impedance of the control material, and then exposing said control material, having uniformly decreased impedance, through said transparency with radiation in a third frequency range to vary the impedance of said control material in inverse proportion to the density of said transparency.
Claim 18
Dependent Claim
20 words
The method of claim 17 in which said radiation in said second frequency ranges includes radiation in the ultraviolet range.
Claim 19
Dependent Claim
34 words
The method of claim 18 in which said radiation in said second frequency range includes radiation in the ultraviolet range and said radiation in said third frequency range includes radiation in the infrared range.
Claim 20
Dependent Claim
25 words
The method of claim 16 in which said transparency and said control material are fixed relative to each other during exposure of said control material.
Claim 21
Dependent Claim
31 words
The method of claim 16 in which said control material, said electroluminescent material, said transparency, and said photosensitive medium are fixed relative to each other during exposure of said photosensitive medium.
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) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |