US3598471A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical contrast enhancement system
Assignee: Corning Glass Works
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Filing: 1968-11-22
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Granted: 1971-08-10
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Expires: 1988-11-22
Abstract
Abstract An optical system for enhancing the contrast of optical images. A sheet of photochromic material is disposed in the Fraunhofer diffraction or first Fourier transform plane of the optical system. Among the wavelengths of light transilluminating the object or transparency is a band which darkens the photochromic material especially at the center of the Fourier series display which contains contrast information (the zeroth order of the Fourier series display). This zeroth order term is attenuated to a much greater degree than the higher order terms which contain the information describing the object or transparency, thus producing an enhanced image.
Inventors
- 👤 William J Baldwin
- 👤 Jurgen R Meyer-Arendt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:36
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/04; G03H1/16
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
200 words
An optical system for enhancing the contrast of an object comprising light source means for providing a light beam containing at least some activating light, the wavelength of which is such that it increases the optical density of photochromic material at least some of the light in said beam being suitable for forming an image, the beam direction of all wavelengths of light in said beam being virtually identical, means for supporting said object in the path of said light beam, first lens means in the path of the light beam emanating from said object for generating at the back focal plane thereof the Fourier transform of said object, and a sheet of photochromic material disposed at the back focal plane of said first lens means, whereby that portion of said activating light, which relates to the contrast of said object and which therefore passes through the zeroth order portion of the Fourier transform, increases the optical density of said zeroth order portion to an extent greater than that to which the optical density of any other portion of said photochromic material is increased, the contrast of the image resulting from light passing through said photochromic material thereby being enhanced.
Claim 2
Dependent Claim
200 words
An optical system for enhancing the contrast of an object comprising light source means for providing a light beam containing at least some activating light, the wavelength of which is such that it increases the optical density of photochromic material at least some of the light in said beam being suitable for forming an image, the beam direction of all wavelengths of light in said beam being virtually identical, means for supporting said object in the path of said light beam, first lens means in the path of the light beam emanating from said object for generating at the back focal plane thereof the Fourier transform of said object, and a sheet of photochromic material disposed at the back focal plane of said first lens means, whereby that portion of said activating light, which relates to the contrast of said object and which therefore passes through the zeroth order portion of the Fourier transform, increases the optical density of said zeroth order portion to an extent greater than that to which the optical density of any other portion of said photochromic material is increased, the contrast of the image resulting from light passing through said photochromic material thereby being enhanced.
Claim 3
Dependent Claim
17 words
An optical system in accordance with claim 1 which further comprises means for bleaching said photochromic material.
Claim 4
Dependent Claim
25 words
An optical system in accordance with claim 1 wherein said mass of photochromic material and said means for converting comprise a lens of photochromic material.
Claim 5
Dependent Claim
42 words
An optical system in accordance with claim 1 wherein said light source means provides two separate wavelengths of light, one of which is an optimum wavelength for activating said photochromic material, the other being an optimum wavelength for viewing said contrast-enhanced image.
Claim 6
Dependent Claim
31 words
An optical system in accordance with claim 1 wherein said light source provides a single band of wavelengths of light which activates said photochromic material and provides said contrast enhanced image.
Claim 7
Dependent Claim
43 words
An optical system in accordance with claim 1 further comprising second lens means in the path of the light emanating from said photochromic plate for forming the inverse Fourier transform of that appearing at the back focal plane of said first lens means.
Claim 8
Dependent Claim
30 words
An optical system in accordance with claim 6 which further comprises filter means disposed in the path of light emanating from said second lens means for passing only visible light.
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) | 1974-08-09 | 1975-02-08 | 1975-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-09 | 1979-02-08 | 1979-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-09 | 1983-02-08 | 1983-08-10 | $7700.00 | Window Closed / Lapsed |