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US4405692A
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Moisture-protected alkali halide infrared windows
Assignee: Raytheon Co
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Filing: 1981-12-04
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Granted: 1983-09-20
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Expires: 2001-12-04
Abstract
Abstract Alkali halide crystals are passivated by a chemical surfactant and overcoated with a plasma polymerized saturated hydrocarbon film to render them suitable for use as optical elements exposed to high humidity and abrasive environmental conditions. These crystals are continuously transmissive to light in the IR.
Inventors
- 👤 Frederick G. Yamagishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:04
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/034; C; C30; C30B; C30B29/00; C30B29/10; C30B29/12; C30B33/00; G; G02; G02B; G02B1/00; G02B1/10; G02B1/14; G02B1/18; B; B05; B05D; B05D1/00; B05D1/62
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
29 words
An infrared optical element comprising an alkali halide crystal having topologically smooth outer surfaces chemically bound to a non-infrared absorbing surfactant and overcoated with a polymerized saturated hydrocarbon film.
Claim 2
Dependent Claim
29 words
An infrared optical element comprising an alkali halide crystal having topologically smooth outer surfaces chemically bound to a non-infrared absorbing surfactant and overcoated with a polymerized saturated hydrocarbon film.
Claim 3
Dependent Claim
56 words
The element of claim 1 wherein said surfactant is a carboxylatodichromium complex selected from the group whose formula is: ##STR2## where R is the alkyl chain of a fatty acid belonging to the homologous series CH 3 (CH 2 ) n CO 2 H where n is an even integer ranging from 2 to about 14.
Claim 4
Dependent Claim
14 words
The element of claim 2 wherein said film is a plasma polymerized alkane film.
Claim 5
Dependent Claim
15 words
The element of claim 3 wherein said surfactant is tetrachloro-μ-hydroxo-μ-myristatodichromium(III) and said alkane is ethane.
Claim 6
Dependent Claim
11 words
The element of claim 4 wherein said alkali halide is NaCl.
Claim 7
Dependent Claim
14 words
The element of claim 1 wherein said film is a plasma polymerized alkane film.
Claim 8
Dependent Claim
55 words
An infrared optical element comprising an alkali halide crystal whose topological smooth surface is passivated by surfactant molecules, each molecule having a polar end and a nonpolar hydrophobic hydrocarbon chain, where said molecules are chemically bound at their polar ends to said surface by covalent bond linkages, and overcoated with a polymerized saturated hydrocarbon film.
Claim 9
Dependent Claim
55 words
An infrared optical element comprising an alkali halide crystal whose topological smooth surface is passivated by surfactant molecules, each molecule having a polar end and a nonpolar hydrophobic hydrocarbon chain, where said molecules are chemically bound at their polar ends to said surface by covalent bond linkages, and overcoated with a polymerized saturated hydrocarbon film.
Claim 10
Dependent Claim
56 words
The element of claim 7 where said surfactant is a carboxylatodichromium complex selected from the group whose formula is: ##STR3## where R is the alkyl chain of a fatty acid belonging to the homologous series CH 3 (CH 2 ) n CO 2 H, where n is an even integer ranging from 2 to about 14.
Claim 11
Dependent Claim
10 words
The element of claim 8 wherein said surfactant is tetrachloro-μ-hydroxo-μ-myristatodichromium(III).
Claim 12
Dependent Claim
27 words
The element of claim 9 wherein said film is an alkane of the formula C n H 2n+2 , where n ranges from 1 to about 5.
Claim 13
Dependent Claim
23 words
The element of claim 10 wherein said film is a plasma polymerized ethane film and said halide is KCl, NaCl, KBr or NaBr.
Claim 14
Dependent Claim
32 words
The element of claim 7 wherein said surfactant in a long chain amine whose structure is CH 3 (CH 3 ) n NH 2 where n ranges from 5 to about 20.
Claim 15
Dependent Claim
9 words
The element of claim 12 wherein n is 17.
Claim 16
Independent Claim
81 words
A method for rendering an alkali halide crystal moisture and abrasive resistant comprising the steps of: forming a topologically smooth crystal surface by sequentially polishing and chemically etching said crystal; applying a chemical surfactant comprised of molecules having a polar end and a nonpolar hydrophobic end to said smooth surface to thereby provide a passivated crystal surface; and subsequently forming a protective film consisting of a polymerized saturated hydrocarbon on said passivated surface thereby providing a protected passivated alkali halide crystal.
Claim 17
Independent Claim
81 words
A method for rendering an alkali halide crystal moisture and abrasive resistant comprising the steps of: forming a topologically smooth crystal surface by sequentially polishing and chemically etching said crystal; applying a chemical surfactant comprised of molecules having a polar end and a nonpolar hydrophobic end to said smooth surface to thereby provide a passivated crystal surface; and subsequently forming a protective film consisting of a polymerized saturated hydrocarbon on said passivated surface thereby providing a protected passivated alkali halide crystal.
Claim 18
Dependent Claim
28 words
The method of claim 14 wherein said surfactant is a carboxylatodichromium complex of a fatty acid having a carbon chain comprising from 2 to about 14 carbon atoms.
Claim 19
Dependent Claim
14 words
The method of claim 14 wherein said film is a plasma polymerized ethane film.
Claim 20
Dependent Claim
15 words
A moisture and abrasive resistant alkali halide crystal prepared by the method of claim 14.
References Cited (Backward Citations)
US4269896A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-19 | 1987-03-21 | 1987-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-19 | 1991-03-21 | 1991-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-19 | 1995-03-21 | 1995-09-20 | $7700.00 | Window Closed / Lapsed |