US4952810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distortion free dewar/coldfinger assembly
Assignee: Raytheon Co
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Filing: 1989-08-23
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Granted: 1990-08-28
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Expires: 2009-08-23
Abstract
Abstract An infrared detector assembly (10) of the type used in munitions and night vision systems having an improved coldfinger assembly (42). Such detector assemblies (10) include a tubular coldfinger (22) which is surrounded by a vacuum and an end-cap (28) mounted to the coldfinger tube (22) to define a cold end (24) which supports the infrared detector array (30) and related components. In accordance with this invention, the coldfinger tube (22) is a thin-walled titanium cylinder and the end-cap (28) is made of tungsten. The components are metallurgically bonded at the cold end (24) by an active brazing alloy deposited during vacuum furnace brazing. The titanium coldfinger (22) provides the necessary bending stiffness to support cold end components. The tungsten end-cap (28) provides a low distortion, thermally stable focal-plane. The metallurgical bond (46) provides for a hermetic seal which inhibits structural distortion during brazing, and during cyclical cooling of the detector assembly (10).
Inventors
- 👤 Kenneth L. Gustafson
- 👤 Timothy S. Romano
- 👤 Nevil Q. Maassen
- 👤 Donald E. Salzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:37
CPC Classifications
F; F17; F17C; F17C3/00; F17C3/02; F17C3/08; F17C3/085; F25; F25D; F25D19/00; F25D19/006; G; G01; G01J; G01J5/00; G01J5/02; G01J5/06; G01J5/061; F17C2201/00; F17C2201/01; F17C2201/0104; F17C2201/0119; F17C2203/00; F17C2203/03; F17C2203/0391; F17C2203/0395; F17C2203/06; F17C2203/0602; F17C2203/0612; F17C2203/0626; F17C2203/0629; F17C2203/0634; F17C2203/0636; F17C2203/0648; F17C2223/00; F17C2223/01; F17C2223/0146; F17C2223/0153; F17C2223/0161; F17C2227/00; F17C2227/03; F17C2227/0337; F17C2227/0339; F17C2270/00; F17C2270/05; F17C2270/0509
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
130 words
An infrared detector assembly comprising: a dewar housing providing an evacuated cavity; a titanium coldfinger tube within said dewar housing, said tube having a cold end; cooling means for cooling said cold end of said titanium coldfinger tube; a tungsten end-cap having a first surface defining a planar mounting platform and a second surface configured to enclose said titanium coldfinger tube at said cold end; a metallurgical bond between said tungsten end-cap and said titanium coldfinger tube; an infrared detector mounted to said first surface of said tungsten end-cap; and said titanium coldfinger tube providing strength for supporting said detector, said tungsten end-cap providing thermal conductivity between said coldfinger tube and said infrared detector, and said metallurgical bond providing a hermetic said for preserving the integrity of said evacuated cavity.
Claim 2
Dependent Claim
130 words
An infrared detector assembly comprising: a dewar housing providing an evacuated cavity; a titanium coldfinger tube within said dewar housing, said tube having a cold end; cooling means for cooling said cold end of said titanium coldfinger tube; a tungsten end-cap having a first surface defining a planar mounting platform and a second surface configured to enclose said titanium coldfinger tube at said cold end; a metallurgical bond between said tungsten end-cap and said titanium coldfinger tube; an infrared detector mounted to said first surface of said tungsten end-cap; and said titanium coldfinger tube providing strength for supporting said detector, said tungsten end-cap providing thermal conductivity between said coldfinger tube and said infrared detector, and said metallurgical bond providing a hermetic said for preserving the integrity of said evacuated cavity.
Claim 3
Dependent Claim
30 words
An infrared detector assembly according to claim 1 wherein said cooling means is a cryogenic cooling system operable to provide a source of thermal energy to cool said infrared detector.
Claim 4
Dependent Claim
19 words
An infrared detector assembly according to claim 1 wherein said titanium coldfinger tube is a titanium right circular cylinder.
Claim 5
Dependent Claim
18 words
An infrared detector assembly according to claim 1 wherein said tungsten end-cap is fabricated from substantially pure tungsten.
Claim 6
Dependent Claim
18 words
An infrared detector assembly according to claim 1 wherein said metallurgical bond comprises an active brazing alloy material.
Claim 7
Dependent Claim
18 words
An infrared detector assembly according to claim 5 wherein said active brazing alloy material comprises a silver-nickel-copper-titanium alloy.
Claim 8
Dependent Claim
27 words
An infrared detector assembly according to claim 1 wherein said second surface of said tungsten end-cap has an inwardly extending radial shoulder having of said cold end.
Claim 9
Dependent Claim
33 words
An infrared detector assembly according to claim 1 wherein said second surface of said tungsten end-cap is substantially parallel to said first surface, said second surface in abutting contact with said cold end.
Claim 10
Dependent Claim
34 words
An infrared detector assembly according to claim 1 wherein said second surface of said tungsten end-cap has inwardly extending peripheral flange having an inner diameter greater than an outer diameter of said cold end.
Claim 11
Dependent Claim
158 words
An infrared detector assembly comprising: a dewar housing providing an evacuated cavity; a titanium coldfinger tube within said dewar housing, said tube having a cold end; coding means for cooling said cold end of said titanium coldfinger tube; tungsten end-cap having a first surface defining a planar mounting platform and a second surface configured to enclose said titanium coldfinger tube at said cold end; a metallurgical bond between said tungsten end-cap and said titanium coldfinger tube; an infrared detector mounted to said first surface of said tungsten end-cap; and said titanium coldfinger tube providing strength for supporting said detector, said tungsten end-cap providing thermal conductivity between said coldfinger tube and said infrared detector, and said metallurgical bond providing a hermetic seal for preserving the integrity of said evacuated cavity; wherein said metallurgical bond is produced in a vacuum environment at the elevated temperature, such that said tungsten end-cap and said titanium coldfinger tube are conducive to metallurgical bonding.
Claim 12
Dependent Claim
158 words
An infrared detector assembly comprising: a dewar housing providing an evacuated cavity; a titanium coldfinger tube within said dewar housing, said tube having a cold end; coding means for cooling said cold end of said titanium coldfinger tube; tungsten end-cap having a first surface defining a planar mounting platform and a second surface configured to enclose said titanium coldfinger tube at said cold end; a metallurgical bond between said tungsten end-cap and said titanium coldfinger tube; an infrared detector mounted to said first surface of said tungsten end-cap; and said titanium coldfinger tube providing strength for supporting said detector, said tungsten end-cap providing thermal conductivity between said coldfinger tube and said infrared detector, and said metallurgical bond providing a hermetic seal for preserving the integrity of said evacuated cavity; wherein said metallurgical bond is produced in a vacuum environment at the elevated temperature, such that said tungsten end-cap and said titanium coldfinger tube are conducive to metallurgical bonding.
Claim 13
Independent Claim
91 words
A method of making coldfinger assembly for an infrared detector assembly of the type wherein said coldfinger assembly has a cold end for supporting a detector which is located within an evacuated cavity, said method comprising the steps of: providing a coldfinger tube made of titanium; providing an end-cap made of tungsten and configured to enclose one end of said coldfinger tube thereby defining said cold end; and metallurgically bonding said end-cap to said coldfinger tube at said cold end wherein said metallurgical bond provides a hermetic, thermally conductive bond therebetween.
Claim 14
Independent Claim
91 words
A method of making coldfinger assembly for an infrared detector assembly of the type wherein said coldfinger assembly has a cold end for supporting a detector which is located within an evacuated cavity, said method comprising the steps of: providing a coldfinger tube made of titanium; providing an end-cap made of tungsten and configured to enclose one end of said coldfinger tube thereby defining said cold end; and metallurgically bonding said end-cap to said coldfinger tube at said cold end wherein said metallurgical bond provides a hermetic, thermally conductive bond therebetween.
Claim 15
Dependent Claim
118 words
A method according to claim 11 further comprises the steps of: placing said tungsten end-cap and said titanium coldfinger tube in a furnace chamber capable of evacuation; aligning said tungsten end-cap and said titanium coldfinger tube so as to define said coldfinger assembly; evacuating said chamber; elevating the temperature of said tungsten end-cap and said titanium coldfinger tube within said chamber to about at least 1750° F.; contacting an active brazing alloy material with said cold end of said coldfinger assembly so as to metallurgically bond said end-cap to said coldfinger; reducing the temperature within said furnace chamber; and removing said coldfinger assembly from said chamber, whereby the resulting metallurgical bond provides for a low distortion coldfinger assembly.
Claim 16
Dependent Claim
24 words
A method according to claim 12 wherein said metallurgical bond is an active brazing alloy comprising an alloy of silver, nickel, copper and titanium.
Claim 17
Independent Claim
110 words
A method for making an electromagnetic detector assembly, said method comprising the step of: providing a dewar housing defining an evacuated cavity; providing a hermetically sealed coldfinger assembly having a hollow coldfinger tube made of titanium and an end-cap made from tungsten, said end-cap being metallurgically bonded to said coldfinger tube so as to enclose a cold end thereof; mounting a detector to said end-cap on a surface opposite said coldfinger tube; and providing a source of thermal energy operable to cool said cold end of said coldfinger assembly whereby said end-cap and the metallurgical bond provide for thermally conductive communication between said detector and said source of thermal energy.
Claim 18
Independent Claim
110 words
A method for making an electromagnetic detector assembly, said method comprising the step of: providing a dewar housing defining an evacuated cavity; providing a hermetically sealed coldfinger assembly having a hollow coldfinger tube made of titanium and an end-cap made from tungsten, said end-cap being metallurgically bonded to said coldfinger tube so as to enclose a cold end thereof; mounting a detector to said end-cap on a surface opposite said coldfinger tube; and providing a source of thermal energy operable to cool said cold end of said coldfinger assembly whereby said end-cap and the metallurgical bond provide for thermally conductive communication between said detector and said source of thermal energy.
Claim 19
Dependent Claim
70 words
A coldfinger assembly for use in an electromagnetic detector assembly of the type having an evacuated dewar for cooling a detector positioned therein, comprising: a hollow coldfinger made from titanium; means for supporting said detector within said evacuated dewar, said supporting means made from tungsten and configured to enclose one end of said coldfinger; a metallurgical bond securing said supporting means to said coldfinger for providing a hermetic seal therebetween.
Claim 20
Dependent Claim
70 words
A coldfinger assembly for use in an electromagnetic detector assembly of the type having an evacuated dewar for cooling a detector positioned therein, comprising: a hollow coldfinger made from titanium; means for supporting said detector within said evacuated dewar, said supporting means made from tungsten and configured to enclose one end of said coldfinger; a metallurgical bond securing said supporting means to said coldfinger for providing a hermetic seal therebetween.
Claim 21
Dependent Claim
15 words
A coldfinger assembly according to claim 15 wherein said hollow coldfinger is a titanium tube.
Claim 22
Dependent Claim
31 words
A coldfinger assembly according to claim 16 wherein said supporting means comprises a tungsten end-cap, said end-cap providing a relatively distortion-free planar surface for supporting said detector within said evacuated dewar.
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) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |