Abstract: An electrical feedthrough (34) is prepared by furnishing an aluminum oxide feedthrough plate (70) and at least one feedthrough pin (80) having a length greater than the thickness of the feedthrough plate (70). A pin bore (78) is formed through the feedthrough plate (70) for each feedthrough pin (80). Each pin bore (78) has a pin bore (78) size greater than the feedthrough pin (80) size, preferably by an amount no greater than that required to permit the penetration of a brazing metal (88) between the pin bore (78) and the feedthrough pin (80). Each feedthrough pin (80) is inserted into its respective pin bore (78) and brazed into place utilizing a metallic active braze alloy (88) and no glassy seal. The feedthrough plate (70) may be simultaneously brazed to a package structure (22) using active or nonactive brazing.

Abstract: A dewar assembly is cleaned, baked out, assembled, and joined in a single vacuum system without exposing the components to ambient atmosphere. The vacuum system preferably has a first chamber with multiple subchambers that can be isolated from each other, and a second chamber that can be isolated from the first chamber. The multiple chambers and subchambers prevent cross contamination during the various process steps, and also permit multiple dewar assemblies to be batch processed at different stages simultaneously. The components of the dewar assembly are loaded into one subchamber and cleaned, and thereafter moved to another subchamber for bakeout. The dewar getter is heated in the second chamber and moved to one of the subchambers for assembly. The components of the dewar assembly are assembled and joined.

Abstract: An infrared dewar-detector assembly for use as a common module which is interchangeable between various military infrared detection systems. The detector is cooled to cryogenic temperature for improved sensitivity. The dewar of the common module incorporates a metal coldfinger mounted on a base plate for attachment to an associated cryo-engine. The coldfinger supports the detector on a beryllium bridge platform. The configurations of both the platform mount and the base plate are selected to minimize the vibrations transmitted to the detector.Signal paths from the detector include ribbon cables extending within the vacuum side of the dewar and having indium dot terminations making direct connections with a ceramic feedthrough header which, on the ambient pressure side of the unit, also includes indium pocket contacts for direct connection to the plug terminals of the unit.

Abstract: A vacuum package assembly (20) is prepared by self-welding the flanges (32 and 43) of two housings (28 and 36) together under an applied pressure, while the housings (28 and 36) and any enclosed structure or device are contained within an evacuated enclosure. The flanges (32 and 43) are preferably made of copper, with their respective self-welding members (34 and 46) specially prepared to enhance self-welding performance. The preferred treatment for the self-welding members (34 and 46) is to deposit a thin layer of nickel onto the self-welding members (34 and 46 ), deposit a thin layer of gold over the nickel, and heat the bonding member to elevated temperature to interdiffuse the gold into the self-welding member (34 and 46 ).

Abstract: A method for bonding the ends of the conductors 52 to circuit pads 54 is disclosed whereby the cable 20 is placed over the circuit pads 54; a bonding tool 44 is pressed against an upper surface 58 of the cable 20; the substrate 46 of the cable 20 is compressed beyond its elastic limit; and ultrasonic energy is applied to the bonding tool 44 and transmitted through the substrate 46 to effect a metallic bond between the conductors 52 and circuit pads 54.

Abstract: A thin film electrical cable 20 is disclosed having a polyimide substrate 46, a layer of titanium 48 on a lower side 50 of the substrate 46, and a plurality of gold conductors 52 on the titanium 48. The thin layers of titanium and gold are preferably sequentially deposited on a clean polyimide film by sputtering. Additional gold is electroplated and separate conductors are delineated. The use of organic adhesive materials to attach the conductors 52 to the substrate 46 is avoided.

Abstract: An infrared detector assembly (10) of the type used in munition and night vision systems having an RF activated getter (50). Such detector assemblies (10) include a tubular coldfinger (22) surrounded by a vacuum and which supports infrared detector array (26) and related components. In accordance with this invention, RF getter (50) is located remote from detector array (26) and engages an inner wall surface (56) of a metallic dewar housing (14). The RF getter (50) is activated via RF inductive heating directly through the metal dewar housing (14) such that sensitive IR detector components and hermetic braze joints are kept below their critical temperature. As a result, the present invention provides longer vacuum life and greater operational reliability of infrared detector assembly (10).

Abstract: A radiation detector assembly (20) includes a radiation detector (2), a silicon readout device (3) coupled to the radiation detector, and a platform 13 for supporting from a first major surface (13a) the readout device and the radiation detector. A second major surface (13b) includes a boss (14) for coupling, via an active brazing operation, to a cryogenic cooler. The platform is monolithic structure comprised of aluminum nitride (AlN) and eliminates at least one adhesive joint found in the prior art. AlN is selected because of its inherent material properties including a higher thermal diffusivity, relative to typical ceramic materials, for providing a reduced cooldown time of the detector to cryogenic temperatures. AlN also has a 300K- 77K thermal contraction characteristic that closely matches that of the silicon readout device and a high modulus of elasticity, thereby reducing distortion of the readout device thus minimizing stresses on indium bump interconnects.

Abstract: A non-evacuated dewar 10 advantageously employs a molecular sieve 30 that serves to adsorb gasses in the dewar when cooled during operation of the detector 24 thereby preventing liquid formation onto the detector. The effects of outgassing and permeation during storage are substantially eliminated because the dewar package is in partial pressure equilibrium with its environment since the interior of the dewar is backfilled with the same inert gas as is in the surrounding outside environment. A second molecular sieve 40 may be used to adsorb moisture which may permeate into the housing.

Abstract: The present invention is directed to an integrated detector dewar cryoengine (10). The integrated detector dewar cryoengine (10) includes a detector (12) for detecting received electromagnetic radiation. The integrated detector dewar cryoengine (10) further comprises expander end cap (18) for removing thermal energy from said detector (12) which is in mechanical communication with said detector (12).

Abstract: An apparatus for mounting a device used for detecting infrared signals is disclosed. The apparatus includes a housing and an expander upon which the device is mounted. An insulating material comprising polymeric foam is disposed between the expander and the housing which allows the apparatus to be cooled without requiring evacuation of the apparatus.