# US 11,993,405 B2 · Thermal control material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,993,405 B2 - Document ID: US11993405B2 - Status: Granted - Kind: B2 - Application number: 16/594,648 - Filed: 2019-10-07 - Published: 2020-08-27 - Granted: 2024-05-28 - Earliest claimed: 2019-02-22 - Assignees: Northrop Grumman Systems Corporation; University of Southern California - Applicants: Vladan Jankovic; Philip W. C. Hon; Luke A. Sweatlock; Michael T. Barako; Mark William Knight; Shao-Hua Wu; Michelle L. Povinelli; Ahmed M. Morsy; Mingkun Chen - Inventors: Vladan Jankovic; Philip W. C. Hon; Luke A. Sweatlock; Michael T. Barako; Mark William Knight; Shao-Hua Wu; Michelle L. Povinelli; Ahmed M. Morsy; Mingkun Chen - Web page: https://patentgrep.com/patent/US11993405B2 ## CPC - B64G 1/50: for temperature control - B32B 3/30: characterised by a layer formed with recesses or projections, e.g. {hollows, grooves, protuberances, ribs (apertured layer B32B3/266; layer with cavities or internal voids B32B3/26)} - B64G 1/226: {Special coatings for spacecraft} - B64G 1/503: {Radiator panels} - B64G 1/58: Thermal protection, e.g. heat shields - C01G 31/02: Oxides - C09K 5/14: Solid materials, e.g. powdery or granular - F28F 21/00: Constructions of heat-exchange apparatus characterised by the selection of particular materials {(coatings for modifying heat-transfer F28F13/18; coatings for preventing the formation of deposits or corrosion F28F19/02)} - G02F 1/0147: {based on thermo-optic effects (G02F1/132 takes precedence)} - H10N 70/231: {based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect} - H10N 70/8613: {Heating or cooling means other than resistive heating electrodes, e.g. heater in parallel} - H10N 70/882: {Compounds of sulfur, selenium or tellurium, e.g. chalcogenides} - H10N 70/8828: {Tellurides, e.g. GeSbTe} - G02F 2202/30: Metamaterials - G02F 2202/32: Photonic crystals - B64G: COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20) - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract Systems and methods are provided for protecting a temperature sensitive object. A system includes a temperature sensitive object and a thermal control material in thermal communication with the temperature sensitive object. The thermal control material has an emissivity that varies as a function of temperature, and includes a substrate comprising a first surface comprising one of a photonic crystal, a metamaterial, a metasurface, and a multilayer film, a solid state phase change material in contact with the surface, and a reflective thin film material at one of a second surface of the substrate, at a surface of the solid state phase change material, and on an opposite side of an optical cavity from the substrate. ## Claims ### Claim 1 A system, comprising: a temperature sensitive object; and a thermal control material in thermal communication with the temperature sensitive object and having an emissivity that varies as a function of temperature, the thermal control material comprising: a substrate comprising a first surface comprising one of a photonic crystal, a metamaterial, a metasurface, and a multilayer film; solid state phase change material in contact with the surface; an optical cavity formed of zinc selenide; and a reflective thin film material positioned on an opposite side of the optical cavity from the substrate. ### Claim 2 (depends on 1) The system of claim 1, wherein the surface is a substrate patterned to form an array of microcones. ### Claim 3 (depends on 1) The system of claim 1, wherein the solid-state phase change material is one of vanadium dioxide and an alloy of vanadium dioxide with a transition metal. ### Claim 4 (depends on 1) The system of claim 1, wherein the solid-state phase change material is one of germanium telluride and an alloy of germanium with another group 6 element. ### Claim 5 (depends on 1) The system of claim 1, wherein solid-state phase change material is a layer having a thickness less than five hundred nanometers. ### Claim 6 (depends on 1) The system of claim 1, wherein the solid-state phase material is selected to have a phase-transition temperature within a desired operating range of the temperature sensitive object. ### Claim 7 (depends on 1) The system of claim 1, wherein the solid-state phase change material can transition between a dielectric state, during which the thermal control material has a first emissivity, and a metallic state, during which the thermal control material has a second emissivity, the second emissivity being at least a factor of two larger than the first emissivity. ### Claim 8 (depends on 1) The system of claim 1, each of the surface and the solid-state phase change material are configured such that a temperature at the temperature sensitive object varies by less than twenty kelvin when the thermal control material is subjected to a time-varying heat flux between one hundred fifty watts per square meter and five hundred watts per square meter. ### Claim 9 (depends on 8) The system of claim 8, wherein each of the temperature sensitive object and the thermal control material are implemented on a spacecraft and the time-varying heat flux is solar illumination. ### Claim 10 A method for providing a thermal control material, comprising: fabricating one of a photonic crystal, a metamaterial, a metasurface, and a multilayer film on a first surface of a substrate; applying a layer of solid-state phase change material to the first surface of the substrate; and positioning a layer of reflective material on an opposite side of an optical cavity from the substrate, the optical cavity being formed of zinc selenide. ### Claim 11 (depends on 10) The method of claim 10, further comprising at least partially enclosing a temperature sensitive device in the substrate. ### Claim 12 (depends on 10) The method of claim 10, wherein the wavelength range of interest is between ten nanometers and thirty microns. ### Claim 13 (depends on 10) The method of claim 10, wherein fabricating the one of a photonic crystal, a metamaterial, a metasurface, and a multilayer film comprises etching the substrate. ### Claim 14 (depends on 13) The method of claim 13, wherein the etching of the substrate provides an array of microcones. ### Claim 15 (depends on 10) The method of claim 10, wherein fabricating the one of a photonic crystal, a metamaterial, a metasurface, and a multilayer film comprises fabricating one of a lithographically patterned and a lithographically grown feature on the substrate. ### Claim 16 (depends on 15) The method of claim 15, wherein the one of a lithographically patterned and a lithographically grown feature provides a photonic metamaterial. ### Claim 17 A thermal control material, comprising: a substrate patterned on a first surface to form an array of microcones; a layer of solid-state phase change material applied to the array of microcones; and a layer of reflective material positioned on an opposite side of an optical cavity from the substrate, the optical cavity being formed of zinc selenide. ### Claim 18 (depends on 17) The thermal control material of claim 17, wherein the array of microcones have a height between one and one-hundred micrometers, and a period between five and fifty micrometers. ### Claim 19 (depends on 17) The thermal control material of claim 17, wherein the layer of solid-state phase change material is a conformal layer of vanadium dioxide having a thickness less than five hundred nanometers. ### Claim 20 (depends on 17) A system, comprising: a temperature sensitive device; and the thermal control material of claim 17, at least partially enclosing the temperature sensitive device.