# US 2013/0153769 A1 · Dewar assembly for ir detection systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153769 A1 - Document ID: US20130153769A1 - Status: Published application - Kind: A1 - Application number: 13/820,297 - Filed: 2011-10-11 - Published: 2013-06-20 - Earliest claimed: 2010-10-14 - Assignees: Semi Conductor Devices—An Elbit Systems-Rafael Partnership - Inventors: Michael Singer - Web page: https://patentgrep.com/patent/US20130153769A1 ## CPC - G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation} - G01J 5/04: Casings - G01J 5/045: {Sealings; Vacuum enclosures; Encapsulated packages; Wafer bonding structures; Getter arrangements (getter arrangements per se H10W76/48, H10P36/03)} - G01J 5/061: by controlling the temperature of the apparatus or parts thereof, e.g. using cooling means or thermostats - G01J 5/0801: Means for wavelength selection or discrimination - G01J 5/0814: {Particular reflectors, e.g. faceted or dichroic mirrors} - G01J 5/0815: {Light concentrators, collectors or condensers} - G01J 5/10: using electric radiation detectors - G02B 19/0019: {having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors)} - G02B 19/0023: {at least one surface having optical power} - G02B 19/0076: {for use with a detector (G02B19/009, G02B19/0095 take precedence)} - G02B 19/009: {for use with infrared radiation} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract A dewar assembly is presented for use in an optical IR detection system defining a light collecting region. The dewar assembly comprises a warm shield unit configured as an enclosure for optically enclosing the light collection region and having an optical window through which incident light enters the dewar. The warm shield defines a reflective inner surface configured such that light portions of the incident light propagating through said optical window onto said inner surface are reflected by the inner surface towards regions outside said light collecting region. ## Claims ### Claim 1 A dewar assembly for use in an optical IR detection system of the kind including an IR detector unit, wherein said dewar assembly comprises: a base comprising radiation absorbing regions and arranged for defining a light collecting region of the dewar assembly; and a warm shield unit having an optical window through which incident light enters the dewar, the warm shield unit being configured as an enclosure for optically enclosing the base, and defining a reflective inner surface configured such that light portions of the incident light propagating through said optical window onto said inner surface are reflected by the inner surface towards regions outside said light collecting region. ### Claim 2 (depends on 1) The dewar assembly of claim 1 wherein said inner surface and an outer surface of said warm shield unit have low emissivity properties reducing the amount of radiation absorbed by said surfaces thereby reducing the amount of radiation emitted from said inner surface under given temperature conditions. ### Claim 3 (depends on 2) The dewar assembly of claim 2 wherein emissivity of said inner surface does not exceed a few percentages. ### Claim 4 The dewar assembly of any one of the preceding claims, wherein said reflective inner surface of the warm shield unit is optically exposed to the said light collecting region. ### Claim 5 The dewar assembly of any one of the preceding claims, wherein a surface of said radiation absorbing regions, facing said inner surface of said warm shield unit, is highly emissive thereby providing efficient radiation absorbance by said surface of the base. ### Claim 6 (depends on 5) The dewar assembly of claim 5 wherein said surface of said radiation absorbing regions has rough texture minimizing reflection of radiation from the surface. ### Claim 7 (depends on 1, 2, 3, 4, 5, 6) The dewar assembly of any one of claims 1 to 6 configured for use in an optical IR detection system of the kind including a cryogenic cooling system for cooling at least a light sensitive region of the IR detector unit; said dewar assembly is adapted for thermal coupling between said cryogenic cooling system and said base for cooling the radiation absorbing regions of the base. ### Claim 8 (depends on 1, 2, 3, 4, 5, 6) The dewar assembly of any one of claims 1 to 6 configured for use in an optical IR detection system of the kind including a temperature stabilization system for stabilizing at least a light sensitive region of the IR detector unit; said dewar assembly is adapted for thermal coupling between said temperature stabilization system and said base for stabilizing the temperature of the radiation absorbing regions of the base. ### Claim 9 The dewar assembly of any one of the preceding claims wherein said warm shield unit comprises a side wall substantially extending from said base towards a surface of said warm shield unit in which said optical window is implemented and defining an optical axis of said dewar assembly designating a general direction of light propagation in between said optical window and said light collecting region. ### Claim 10 (depends on 9) The dewar assembly claim 9 wherein said inner surface comprises surfaces of said side wall facing towards an interior of said dewar assembly. ### Claim 11 (depends on 9, 10) The dewar assembly any one of claims 9 and 10 wherein an outer surface of said warm shield unit comprises surfaces of said side wall facing towards an exterior of said dewar assembly. ### Claim 12 (depends on 9) The dewar assembly claim 9 wherein the side wall comprises multiple facets jointed together, said inner surface being formed by jointed surfaces of said facets. ### Claim 13 (depends on 9) The dewar assembly claim 9, wherein a shape of cross section contour of said inner surface taken within a secant plane containing said optical axis is configured such that the incident light passing through said optical window onto said inner surface is reflected toward at least one radiation absorbing region of said base. ### Claim 14 (depends on 13) The dewar assembly of claim 13, wherein the shape of cross section contour of said inner surface is designed for reducing a surface area of said inner surface thereby enabling to increase a signal to noise ratio of light collection through said light collecting region by reducing amount of thermal radiation emissions from said inner surface. ### Claim 15 (depends on 14) The dewar assembly claim 14 wherein said shape has concaved curvature. ### Claim 16 (depends on 13, 14, 15) The dewar assembly of any one of claims 13 to 15, wherein said shape of the cross section contour is in the form of an elliptical arc. ### Claim 17 (depends on 13, 14, 15) The dewar assembly of any one of claims 13 to 15, wherein said shape of the cross section contour is in the form of a hyperbolic arc. ### Claim 18 An optical IR detection system comprising: an IR detector unit having a light collecting region; and a dewar assembly comprising a warm shield unit having an optical window through which incident light enters the dewar, the warm shield unit being configured as an enclosure for optically enclosing the light collecting region, and defining a reflective inner surface configured such that light portions of the incident light propagating through said optical window onto said inner surface are reflected by the inner surface towards regions outside said light collecting region.