Patent US4946231A successfully refreshed from Google Patents.
US4946231A
Expired / Lapsed
US
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Polarizer produced via photographic image of polarizing grid
Assignee: United States Department of the Army
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Filing: 1989-05-19
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Granted: 1990-08-07
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Expires: 2009-05-19
Abstract
Abstract A method of forming polarization grids for infrared optic systems is provd which uses conventional photographic media such as ordinary black and white film or plates in conjunction with a silver reduction process and far-infrared coating techniques.
Inventors
- 👤 Helmut H. Pistor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:13
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/30; G02B5/3025; G02B5/3058; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
147 words
A method for forming a far-infrared polarization grating comprising the steps of: optically projecting an image of a Ronchi ruling, wherein the ruling comprises numerous parallel lines impressed on the front surface of a transparent substrate, by illuminating the back surface of said substrate with a collimated light source; focussing said image on a sheet of ordinary black and white film, having a backing layer and an emulsion layer with silver halides dispersed therein, such that the spacing between said parallel lines is about a quarter of the wavelength in the far-infrared range to be polarized; developing said film to form a black image of said ruling formed of colloidal silver particles dispersed uniformly through the thickness dimension of said emulsion; and further processing said film using a silver diffusion procedure to obtain an electrically conductive image of said ruling in thin strips of specularly reflecting silver.
Claim 2
Independent Claim
147 words
A method for forming a far-infrared polarization grating comprising the steps of: optically projecting an image of a Ronchi ruling, wherein the ruling comprises numerous parallel lines impressed on the front surface of a transparent substrate, by illuminating the back surface of said substrate with a collimated light source; focussing said image on a sheet of ordinary black and white film, having a backing layer and an emulsion layer with silver halides dispersed therein, such that the spacing between said parallel lines is about a quarter of the wavelength in the far-infrared range to be polarized; developing said film to form a black image of said ruling formed of colloidal silver particles dispersed uniformly through the thickness dimension of said emulsion; and further processing said film using a silver diffusion procedure to obtain an electrically conductive image of said ruling in thin strips of specularly reflecting silver.
Claim 3
Dependent Claim
23 words
The method according to claim 1, further including the step of: treating said image to protect said strips from chemical or mechanical damage.
Claim 4
Dependent Claim
25 words
The method according to claim 2, wherein said step of treating consists of: plating said strips with gold by means of a gold toning bath.
Claim 5
Dependent Claim
29 words
The method according to claim 2, wherein said step of treating consists of: coating the emulsion surface of said film with a hard non-abrasive material transparent to far-infrared radiation.
Claim 6
Dependent Claim
27 words
The method according to claim 2, wherein said step of treating consists of: vacuum depositing a layer of silicon monoxide on the emulsion layer of said film.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-06 | 1994-02-05 | 1994-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-06 | 1998-02-05 | 1998-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-06 | 2002-02-05 | 2002-08-07 | $7700.00 | Window Closed / Lapsed |