US3724938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable contrast image projection
Assignee: Individual
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Filing: 1969-11-28
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Granted: 1973-04-03
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Expires: 1989-11-28
Abstract
Abstract A system for controlling the contrast of projected images includes a polarizer, phase plate, analyzer, and image matrix comprising an exposed and developed photographic film defining an original image having light and dark portions. A beam of polarized light of a selected frequency is directed through the system and onto a screen. The polarizer, phase plate, and analyzer are adjustable to vary the contrast of the projected image through partial or complete extinction, by destructive interference, only of light passing to the projected image from the unexposed portions of the film. For light of a given intensity incident upon the film, the contrast, i.e., the pattern of light intensities, in the projected image, is different from that of the original image. This occurs because the intensity of light in the projected image passing thereto from the unexposed film portions is diminished through at least partial extinction. The background dark level, however, of the original image defined by the intensity of light passing from the exposed matrix portions is substantially unchanged in the projected image, relatively little extinction of such light occurring. Contrast in the projected image may be converted from intensity to color by using a projected beam of light with a mixture of different frequencies and adjusting the polarizing and phase plate elements to extinguish partially or completely light of a particular frequency. The image matrix comprises an exposed and developed film having a non-birefringent substrate and a superposed partially birefringent composition containing metallic silver and oriented fatty acid silver salt crystals.
Inventors
- 👤 D Nepela
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:22
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/28
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
71 words
The system of claim 1 wherein said optic axis and said azimuth of transmittance of the electric vector of said analyzer are orientable at selectively variable angles with respect to the plane of polarization of said polarized light, and wherein said phase varying means is adjustable for at least partially extinguishing polarized light passing thereto from selected said matrix volume elements, depending on the birefringence of said selected matrix volume elements.
Claim 2
Dependent Claim
23 words
The system of claim 2 wherein said phase varying means comprises a layer of birefringent material disposed on the surface of said matrix.
Claim 3
Dependent Claim
110 words
The system of claim 2 wherein a portion of said matrix volume elements have a substantially equal birefringence and the remainder of said matrix volume elements have varying birefringence, the birefringence of said other matrix volume elements differing substantially from the birefringence of said matrix volume elements having substantially equal birefringence and wherein said azimuth of transmittance of the electric vector of said analyzer and said optic axis are orientable at selectively variable angles with respect to the plane of polarization of said polarized light, and wherein said phase varying means is adjustable for at least partially extinguishing polarized light passing thereto from said substantially equally birefringent matrix volume elements.
Claim 4
Dependent Claim
53 words
The system of claim 4 wherein said matrix comprises an exposed and developed photographic film and wherein said birefringence of said matrix volume elements varies with exposure of said matrix volume elements, said elements having substantially equal birefringence being substantially unexposed and said other matrix volume elements having substantially varying birefringence being exposed.
Claim 5
Dependent Claim
91 words
The system of claim 5 wherein said azimuth of transmittance of the electric vector of said analyzer is oriented substantially paralel to said plane of polarization of said polarized light, and said optic axis of said matrix volume elements is oriented at an angle of substantially 45* to said plane of polarization of said polarized light and wherein said phase varying means is adjusted to introduce a phase difference of substantially an uneven integral multiple of 180* between E and O light beams passing thereto from said substantially unexposed volume elements.
Claim 6
Dependent Claim
14 words
The system of claim 6 wherein said unexposed matrix volume elements are substantially isotropic.
Claim 7
Dependent Claim
27 words
The system of claim 2 wherein said matrix comprises an exposed photographic film developable so that upon development birefringence of said matrix volume elements varies with exposure.
Claim 8
Dependent Claim
14 words
The system of claim 1 wherein said polarized light comprises a range of wavelengths.
Claim 9
Independent Claim
105 words
A system for selectively varying light contrast in an image projected from an original image along an optical path comprising: an image matrix in the optical path including volume elements having birefringence defining said original image through a pattern of light absorptive capacities, the birefringence of said volume elements varying with the light absorptive capacity, said matrix comprising: fatty aCid crystals and metallic silver isotropic volume elements and birefringent fatty acid silver salt crystals, at least a portion of which acid and salt crystals are unidirectionally oriented; analyzer means for disposition in the optical path; and phase varying means for disposition in the optical path.
Claim 10
Dependent Claim
30 words
The system of claim 10 wherein said matrix is disposed upon a non-birefringent substrate which comprises a material selected from the group consisting of glass, cellulose esters, polycarbonates and polystyrene.
Claim 11
Dependent Claim
20 words
The system of claim 10 wherein said fatty acids comprise carboxylic acids having between about 9 and 22 carbon atoms.
Claim 12
Dependent Claim
23 words
The system of claim 10 wherein at least about 30 percent of said fatty acids and fatty acid silver salts are unidirectionally oriented.
Claim 13
Dependent Claim
22 words
The system of claim 10 wherein said fatty acid, fatty acid salts and metallic silver are present within an essentially non-birefringent binder.
Claim 14
Independent Claim
106 words
A system for projecting along a projection path an image of selectively variable contrast to that of an original image comprising: an image matrix for disposition along said projection path and including volume elements, said volume elements defining said original image by their absorptive capacities with respect to electromagnetic wave energy passing through said volume elements, said elements being birefringent to a varying degree with varying electromagnetic wave energy absorptive capacity, and having a fast axis; and destructive interference means for disposition along said projection path and for at least partially extinguishing electromagnetic wave energy passing through at least a portion of said image matrix elements.
Claim 15
Dependent Claim
19 words
The invention as set forth in claim 15 wherein said image matrix includes volume elements of substantially differing birefringence.
Claim 16
Dependent Claim
19 words
The invention as set forth in claim 15 wherein said image matrix includes volume elements having substantially equal birefringence.
Claim 17
Dependent Claim
26 words
The invention as set forth in claim 17 wherein said matrix volume elements having substantially equal birefringence have substantially different birefringence from other said volume elements.
Claim 18
Dependent Claim
29 words
The invention as set forth in claim 18 wherein said matrix volume elements having substantially equal birefringence have a substantially higher birefringence than said other said matrix volume elements.
Claim 19
Dependent Claim
134 words
The invention as set forth in claim 19 wherein said destructive interference means comprises a variable phase plate and an analyzer, said variable phase plate and said analyzer being successively disposed along said projection path following said image matrix and further including a light source and a polarizer, said light source being positioned to direct monochromatic light through said polarizer, said polarizer being positioned to transmit light from said light source to said image matrix, the azimuth of transmittance of the electric vector of said polarizer and the azimuth of transmittance of the electric vector of said analyzer being disposed substantially parallel, and wherein said variable phase plate is adjustable to vary contrast in said projected image by at least partially extinguishing light passing thereto from said matrix volume elements having substantially higher birefringence.
Claim 20
Dependent Claim
65 words
The invention as set forth in claim 20 wherein said light source directs polychromatic light through said polarizer and wherein said variable phase plate is adjustable to vary contrast in said projected image by at least partially extinguishing light of at least one wavelength included in said beam and passing to said variable phase plate from said matrix volume elements having said substantially higher birefringence.
Claim 21
Independent Claim
106 words
A method for projecting an image of variable contrast from an original image comprising the steps of: a. passing light polarized in a determined plane through an image matrix having elements defining said original image, said elements being birefringent and light absorptive in related degrees and having an optic axis; b. passing the light from said matrix successively through a variable phase plate and an analyzer; and c. selectively adjusting said variable phase plate and selectively varying the orientation of the azimuth of transmittance of the electric vector of said analyzer for at least partially extinguishing in said analyzer light passing thereto from said image matrix.
Claim 22
Dependent Claim
68 words
The method as set forth in claim 22 wherein the orientations of said optic axis and said azimuth of transmittance of the electric vector of said analyzer are selectively varied with respect to said plane of polarization of said light and said variable phase plate is adjusted, for at least partially extinguishing in said analyzer light passing thereto from said matrix elements having the highest degree of birefringence.
Claim 23
Dependent Claim
49 words
The method as set forth in claim 23 wherein the azimuth of transmittance of the electric vector of said analyzer is oriented substantially at a 45* angle with the optic axis of said image matrix element and is oriented substantially parallel to said plane of polarization of said light.
Claim 24
Dependent Claim
47 words
The method as set forth in claim 24 wherein said variable phase plate is adjusted for differentially retarding to an uneven integral multiple of 180* the phase of E and O beams in light passing thereto from said image matrix elements having the highest degree of birefringence.
Claim 25
Independent Claim
92 words
A method for converting an original image defined by differing light absorptive capacities of image elements of a transparency into a projected image defined by differing colors, said image elements having birefringence related to their light absorptive capacities, comprising: a. passing polarized polychromatic light through said transparency; b. passing the light successively through a variable phase plate and an analyzer which are adjusted for at least partially extinguishing a selected wavelength of light within said polarized light and passing thereto from image elements of said transparency having a selected degree of birefringence.
Claim 26
Dependent Claim
138 words
In a system for projection of an image from an original image wherein light is transmitted through said image to a receiving surface, the improvement comprising the combination: a. a transparency comprising image elements having varying degrees of light absorptive capacity, whereby said original image is defined, and varying degrees of birefringence, said degrees of birefringence and said degrees of light absorptive capacity being related; b. a variable phase plate disposed between said matrix and said projected image; and c. an analyzer disposed between the variable phase plate and the projected image; whereby the contrast of said projected image may be selectively varied by adjusting the orientation of the azimuth of transmittance of the electric vector of said analyzer and adjusting said variable phase plate for variable extinction in said analyzer of light passing thereto from said transparency.
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |