A multi-spectral stealth skin and its adaptive camouflage system

Abstract

The present invention provides a multispectral stealth skin and its adaptive camouflage system. The multispectral stealth skin comprises a low-infrared emissive layer, a microwave absorption layer, and a heating layer, connected sequentially from top to bottom. The microwave absorption layer includes a visible light stealth layer, which is an environmental mimicry film prepared by injection molding thermochromic capsules and polydimethylsiloxane. Applications include applying the multispectral stealth skin to an environmentally adaptive multispectral compatible stealth skin system. The adaptive camouflage system comprises an environmental recognition unit, a control system unit, and the multispectral stealth skin. The multispectral stealth skin and adaptive camouflage system of the present invention possess strong radar-infrared stealth and environmentally adaptive visible light stealth capabilities, and have high commercial and promotional value.

Description

Technical Field

[0001] The present invention relates to the field of multi-band compatible stealth technology, and in particular to a multi-spectral stealth skin and an adaptive camouflage system thereof. Background Art

[0002] With the advancement of science and technology and the rapid development of strategic weapons, precision strike methods based on multi-band combined and multi-gradient depth detection technology have become the mainstream of modern battlefields. Among them, the multi-gradient detection system composed of long-range radar detection, medium-range infrared detection, and close-range visible light remote sensing has been widely used. Therefore, for various strategic equipment that require key protection, having radar stealth, infrared stealth, and visible light stealth can greatly improve survival rates on the battlefield. For mobile military equipment such as tanks and armored vehicles, visible light stealth requires adaptive adaptation to the surrounding environment. In summary, the development of a system with radar-infrared stealth and environmentally adaptive visible light stealth is extremely important.

[0003] Existing stealth-compatible skins primarily target radar-infrared compatibility. These are achieved through metamaterials that artificially manipulate electromagnetic parameters to achieve remarkable physical properties such as negative refraction and perfect lenses. Functionally, they fall into two categories: 1. Achieving higher visible light transmittance at the thinnest possible thickness, primarily used in windows of aircraft, tanks, and other equipment; 2. Sacrificing thickness and light transmittance to achieve lower infrared emissivity and wider-band microwave absorption. The former, due to its superior light transmittance, offers further compatibility with visible light stealth, but exhibits poor radar-infrared stealth performance. The latter, due to its opacity, offers limited compatibility with visible light stealth, but possesses excellent radar-infrared stealth performance. Striving to achieve compatibility with visible light stealth while maintaining excellent infrared-radar stealth performance has become a key challenge in the development of stealth technology.

[0004] Chinese patent CN117471404A discloses an adaptive camouflage skin electronic and adaptive stealth system. The system utilizes a vertically stacked structure consisting of, from the outside in, a low-infrared emissivity layer, a radar absorption layer, and an adaptive color-changing layer. This achieves a multifunctional integrated design that combines infrared, visual, and radar stealth. The system achieves multi-band intelligent adaptive stealth, combining low radiation in the mid- and far-infrared bands of 3 to 15 μm, effective radar absorption in a wide frequency band of 10 to 37.5 GHz, and adaptive color change in the range of 0.38 to 0.78 μm. The design concept of this invention is to place the adaptive color-changing layer at the very bottom, which limits its infrared-radar stealth performance to a certain extent. Despite its high red emissivity and weak absorption in the low-frequency band of 2 to 10 GHz, the ambient light sensor used for background recognition can only transmit single-color data, making it ineffective in environments with complex colors and exhibiting poor adaptability. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a multi-spectral stealth skin to solve the problem that conventional stealth skins in the prior art cannot achieve simultaneous stealth against radar, infrared light, and visible light and have poor adaptability to color.

[0006] In order to overcome the defects of the above-mentioned prior art, the present invention provides a multi-spectral stealth skin, which includes a low-infrared emission layer, a microwave absorption layer and a heating layer connected in sequence from top to bottom. The microwave absorption layer includes a visible light stealth layer, and the visible light stealth layer is an environmental mimicry film prepared by an injection molding process of thermochromic capsules and polydimethylsiloxane.

[0007] The multi-spectral stealth skin of the present invention, through the above-mentioned structural design, can well perform adaptive stealth against radar, infrared light, and visible light, and has strong adaptability to complex color environments.

[0008] In a possible embodiment, the microwave absorption layer includes a first microwave loss layer, a second base layer, an environmental mimic film, a first foam medium layer, a second microwave loss layer, a third base layer, a second foam medium layer, a third microwave loss layer, a fourth base layer, and a third foam medium layer, which are connected in sequence from top to bottom.

[0009] The present invention adopts a microwave absorption layer design with the above structure, and adopts a three-layer microwave absorption layer design as a whole, which can absorb microwave signals. The microwave signals can be converted into heat by the three middle microwave absorption layers through resonance absorption, dielectric loss, etc., thereby suppressing the reflection of microwaves, making it impossible for radar to detect, thereby achieving radar stealth and improving the microwave absorption rate.

[0010] In a possible embodiment, the first foam medium layer, the second foam medium layer, and the third foam medium layer are made of polymethacrylimide, expandable polyethylene, or a composite material of polymethacrylimide and expandable polyethylene; the second base layer, the third base layer, and the fourth base layer are PET bases.

[0011] In a possible embodiment, the material of the first microwave loss layer, the second microwave loss layer and the third microwave loss layer is one of indium tin oxide, antimony tin oxide and aluminum-doped zinc oxide, or a composite material of indium tin oxide, antimony tin oxide and aluminum-doped zinc oxide; the sheet resistance of the first microwave loss layer and the second microwave loss layer is 220-280Ω / sq; the sheet resistance of the third microwave loss layer is 120-180Ω / sq.

[0012] By selecting the foam medium of the above-mentioned specific material, as well as the material selection and square resistance limitation of the microwave loss layer, the absorption effect of the microwave absorption layer is further improved.

[0013] In one possible embodiment, the low infrared emission layer includes an infrared wave intercepting layer, a first base layer, and an air dielectric layer connected in sequence from top to bottom. The material of the infrared wave intercepting layer is one of indium tin oxide, antimony tin oxide, and aluminum-doped zinc oxide, and a composite material. The square resistance of the infrared wave intercepting layer is 5-12Ω / sq; the first base layer is a PET base, and the air dielectric layer is obtained by laser engraving on the surface of the first base layer.

[0014] In a possible embodiment, the infrared wave intercepting layer is fixed on the first base layer by photolithography and dry etching; the first microwave loss layer, the second microwave loss layer and the third microwave loss layer are respectively fixed on the second base layer, the third base layer and the fourth base layer by laser etching.

[0015] By fixing the above-mentioned infrared wave intercepting layer and microwave loss layer, the absorption and suppression effects of the multi-spectral stealth skin in the present invention are further improved.

[0016] In a possible implementation, the heating layer is one of a graphene heating plate, a silica gel heating plate and a ceramic heating plate, or a heating plate made of a composite material of graphene, silica gel and ceramic.

[0017] By selecting the above-mentioned heating plate, it is possible to heat the environmental mimicry film, thereby changing its color and achieving invisibility.

[0018] In a possible embodiment, the thermochromic capsule includes a composite material formed by combining one or more materials of two-stage color-changing, multi-stage color-changing, colorless-to-colored or colored-to-colorless temperature-changing capsules at different temperatures.

[0019] In a possible embodiment, the thermochromic capsule is a thermochromic capsule that changes from grass green to khaki at 31°C.

[0020] In one possible implementation, the method for preparing the environmental mimicry film includes:

[0021] S1 polydimethylsiloxane polydimethylsiloxane and SE1700 curing agent in a mass ratio of 10: 1 after stirring to form a glue, and then the glue and thermochromic capsules in accordance with the mass ratio range of 5: 1 to 10: 1 mixed;

[0022] S2. Place the mixture in S1 in an internal vacuum machine and then reduce the vacuum degree of the vacuum chamber to less than 3.0×10 -3 Pa, let it stand for 30 minutes;

[0023] S3. The vacuum chamber was restored to normal pressure and the mixture was removed. The mixture was then poured into the coaxial mold and the mimetic film mold, respectively, and then the mold was placed in an 80°C oven for 2h;

[0024] S4. The mold is removed and demoulded to obtain an environmental mimicking film.

[0025] Another technical problem to be solved by the present invention is to provide an adaptive camouflage system, which includes applying the multi-spectral stealth skin to an environmentally adaptive multi-spectral compatible stealth skin system to solve the problem that the existing stealth skin system cannot simultaneously take into account radar, infrared light, and visible light stealth.

[0026] In order to solve the above technical problems, the present invention provides an application of a multi-spectral stealth skin, wherein the application includes applying the multi-spectral stealth skin to an environment-adaptive multi-spectral compatible stealth skin system, wherein the stealth skin system includes: an environment recognition unit, a control system unit, and a multi-spectral stealth skin;

[0027] The environment recognition unit is connected to the control system unit and is used to collect the environment background image and convert it into an electrical signal and input it into the control system unit;

[0028] The control system unit is connected to the multi-spectral stealth skin, and is used to receive and analyze the electrical signal output by the environment recognition unit, and convert the electrical signal into a control information source of the multi-spectral stealth skin and input it into the multi-spectral stealth skin.

[0029] In one possible implementation, the working process of the environment-adaptive multi-spectral compatible stealth skin system includes:

[0030] Visible light stealth: The environment recognition unit obtains background information, which is then converted into an electrical signal and input into the control system unit. The control system unit changes the temperature of the heating layer of the multi-spectral stealth skin, and the environmental mimicry film is fitted with a color similar to the background, thereby achieving environmental mimicry, i.e., visible light stealth;

[0031] Radar stealth: The microwave absorption layer of the multi-spectral stealth skin converts microwaves into heat through resonance absorption and dielectric loss, thereby suppressing microwave reflection and making it impossible for radar to detect, thus achieving radar stealth;

[0032] Infrared stealth: The infrared wave emissivity is suppressed through the low infrared emissive layer, which hinders the emission of internal infrared waves, thereby avoiding the detection of target infrared waves by infrared detectors.

[0033] The present invention proposes an environment-adaptive multi-spectral compatible stealth skin system, which can achieve low infrared emissivity (less than 0.227), broadband microwave absorption (>90%) in the range of 2.53-34.56 GHz, and adaptive visible light stealth in various environments such as grasslands and deserts. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the environment-adaptive multi-spectral compatible stealth skin system of the present invention;

[0035] Figure 1 Among them, 1. Environmental recognition unit; 2. Control system unit; 3. Multi-spectral stealth skin;

[0036] Figure 2 This is a structural analysis diagram of the multi-spectral stealth skin of the present invention;

[0037] Figure 2 In the figure, 301 is an infrared wave intercepting layer; 302 is a first base layer; 303 is an air dielectric layer; 304 is a first microwave loss layer; 305 is a second base layer; 306 is an environmental mimic film; 307 is a first foam dielectric layer; 308 is a second microwave loss layer; 309 is a third base layer; 310 is a second foam dielectric layer; 311 is a third microwave loss layer; 312 is a fourth base layer; 313 is a third foam dielectric layer; 314 is a heating layer;

[0038] Figure 3 This is an electromagnetic parameter diagram of the multi-spectral stealth skin prepared in Example 1 of the present invention;

[0039] Figure 4 This is a flowchart of the control unit of the environment-adaptive multi-spectral compatible stealth skin system of the present invention;

[0040] Figure 5 This is a flowchart of the algorithm flow of the environment-adaptive multi-spectral compatible stealth skin system of the present invention;

[0041] Figure 6 The following are the dimensions and structures of each layer of the multi-spectral stealth skin of the present invention, wherein a is a schematic structural diagram of the low infrared emission layer, b and c are schematic structural diagrams of the microwave absorption layer, and d is a schematic height diagram of the multi-spectral stealth skin;

[0042] Figure 7 This is a graph showing the infrared stealth performance test results of the environment-adaptive multi-spectral compatible stealth skin system of the present invention;

[0043] Figure 8 The figures show the simulation results and experimental test results of the radar stealth performance test of the environment-adaptive multi-spectral compatible stealth skin system of the present invention;

[0044] Figure 9 、 Figure 10 This is a graph showing the angular stability test results of the radar stealth performance test of the environment-adaptive multi-spectral compatible stealth skin system of the present invention;

[0045] Figure 11 、 Figure 12 This is a graph showing the environmental mimicry performance test results of the environment-adaptive multi-spectral compatible stealth skin system of the present invention in grassland and desert environments. DETAILED DESCRIPTION

[0046] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of the present application and are not intended to limit the scope of protection of the embodiments of the present application. Those skilled in the art may adjust them as needed to suit specific application scenarios.

[0047] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0048] In the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0049] The present invention provides a multi-spectral stealth skin, which includes a low-infrared emission layer, a microwave absorption layer, and a heating layer connected in sequence from top to bottom. The microwave absorption layer includes a visible light stealth layer, and the visible light stealth layer is an environmental mimicry film prepared by an injection molding process of thermochromic capsules and polydimethylsiloxane.

[0050] As a preferred solution, the thermochromic capsule includes a composite material formed by combining one or more materials of two-stage color-changing, multi-stage color-changing, colorless-to-colored or colored-to-colorless temperature-changing capsules at different temperatures.

[0051] As a preferred solution, the thermochromic capsule is a thermochromic capsule that changes from grass green to khaki at 31°C.

[0052] As a preferred solution, the microwave absorption layer includes a first microwave loss layer, a second base layer 305, an environmental mimic film 306, a first foam medium layer 307, a second microwave loss layer 308, a third base layer 309, a second foam medium layer 310, a third microwave loss layer 311, a fourth base layer 312, and a third foam medium layer 313, which are connected in sequence from top to bottom.

[0053] As a preferred solution, the first foam medium layer 307, the second foam medium layer 310, and the third foam medium layer 313 are made of polymethacrylimide, expandable polyethylene, or a composite material of polymethacrylimide and expandable polyethylene; the second base layer 305, the third base layer 309, and the fourth base layer 312 are PET bases, and the air medium layer 303 is obtained by laser engraving on the surface of the first base layer 302.

[0054] As a preferred solution, the material of the first microwave loss layer 304, the second microwave loss layer 308 and the third microwave loss layer 311 is one of indium tin oxide, antimony tin oxide and aluminum-doped zinc oxide, or a composite material of indium tin oxide, antimony tin oxide and aluminum-doped zinc oxide; the sheet resistance of the first microwave loss layer 304 and the second microwave loss layer 308 is 220-280Ω / sq; the sheet resistance of the third microwave loss layer 311 is 120-180Ω / sq.

[0055] As a preferred solution, the low-infrared emission layer includes an infrared wave intercepting layer 301, a first substrate layer 302, and an air dielectric layer 303, which are connected in sequence from top to bottom. The material of the infrared wave intercepting layer 301 is one of indium tin oxide, antimony tin oxide, aluminum-doped zinc oxide, and a composite material. The square resistance of the infrared wave intercepting layer 301 is 5-12Ω / sq; the first substrate layer 302 is a PET substrate.

[0056] As a preferred solution, the infrared wave intercepting layer 301 is fixed on the first base layer 302 by photolithography and dry etching; the first microwave loss layer 304, the second microwave loss layer 308 and the third microwave loss layer 311 are respectively fixed on the second base layer 305, the third base layer 309 and the fourth base layer 312 by laser etching.

[0057] As a preferred solution, the heating layer 314 is one of a graphene heating plate, a silica gel heating plate and a ceramic heating plate, or a composite heating plate of graphene, silica gel and ceramic.

[0058] As a preferred solution, the method for preparing the environmental mimicry film includes:

[0059] S1 polydimethylsiloxane and SE1700 curing agent in a mass ratio of 10: 1 after stirring to form a glue, and then the glue and thermochromic capsules in accordance with the mass ratio range of 5: 1 to 10: 1 mixed;

[0060] S2. Place the mixture in S1 in an internal vacuum chamber, evacuate the chamber to a vacuum level of less than 3.0 × 10-3 Pa, and allow to stand for 30 minutes.

[0061] S3. The vacuum chamber was restored to normal pressure and the mixture was removed. The mixture was then poured into the coaxial mold and the mimetic film mold, respectively, and then the mold was placed in an 80°C oven for 2h;

[0062] S4. The mold is taken out and demoulded to obtain the environmental mimicry film 306.

[0063] The present invention also provides a multi-spectral stealth skin adaptive camouflage system, the adaptive camouflage system comprising: an environment recognition unit, a control system unit and the multi-spectral stealth skin;

[0064] The environment recognition unit 1 is connected to the control system unit 2 and is used to collect the environment background image and convert it into an electrical signal and input it into the control system unit 2;

[0065] The control system unit 2 is connected to the multi-spectral stealth skin 3 and is used to receive and analyze the electrical signal output by the environment recognition unit 1, and convert the electrical signal into a control information source of the multi-spectral stealth skin 3 and input it into the multi-spectral stealth skin 3.

[0066] As a preferred solution, the working process of the adaptive camouflage system includes:

[0067] Visible light stealth: The environment recognition unit 1 obtains background information, which is then converted into an electrical signal and input into the control system unit 2. The control system unit changes the temperature of the heating layer 314 of the multi-spectral stealth skin 3, and the environmental mimicry film 306 is fitted with a color similar to the background, thereby achieving environmental mimicry, i.e., visible light stealth;

[0068] Radar stealth: The microwave loss layers in the microwave absorption layer of the multi-spectral stealth skin 3 convert microwaves into heat through resonance absorption and dielectric loss, thereby suppressing microwave reflection and making it impossible for radar to detect, thereby achieving radar stealth;

[0069] Infrared stealth: The low infrared emissive layer blocks the emission of internal infrared waves and the absorption of external infrared waves, thereby avoiding detection of the target by infrared detectors.

[0070] The present invention is further described below in combination with the above technical solutions of the present invention:

[0071] Example 1:

[0072] This embodiment provides a multi-spectral stealth skin and its adaptive camouflage system. The multi-spectral stealth skin 3 specifically includes:

[0073] The multi-spectral stealth skin 3 uses a periodic array of indium tin oxide film with a square resistance of 8.5Ω / sq as the infrared wave interception layer 301 and an air dielectric layer 303 at its bottom as the low infrared emission layer; a square indium tin oxide film with a square resistance of 150Ω / sq is used as the first microwave loss layer 304, the second microwave loss layer 308, and a square indium tin oxide film with a square resistance of 250Ω / sq is used as the third microwave loss layer 311, which is bonded to the first foam dielectric layer 307, the second foam dielectric layer 310, and the third foam dielectric layer 313 as a microwave absorption layer, and the foam material is polymethacrylimide; an environmental mimic film 306 prepared by an injection molding process of thermochromic capsules that can change from grass green to khaki at 31°C and polydimethylsiloxane is used as a visible light stealth layer; a silicone rubber heating plate is used as the heating layer 314, as shown in the attached figure. Figure 2 As shown, the infrared wave intercepting layer 301 is prepared on the first substrate layer 302 by using a photolithography process and a dry etching process; the first microwave loss layer 304, the second microwave loss layer 308 and the third microwave loss layer 311 are fixed on the second substrate layer 305, the third substrate layer 309 and the fourth substrate layer 312 respectively by using a laser etching process; the multi-spectral stealth skin in the present invention is assembled by preparing each layer structure separately, and then bonding each prepared film layer to the adjacent functional layer by a high-transmittance adhesive.

[0074] The thickness of the air medium layer 303 is 1.25 mm; the thickness of the foam medium layer 307, the foam medium layer 310, and the foam medium layer 313 is 2.5 mm;

[0075] The indium tin oxide film is deposited on a substrate with a thickness of 0.125 mm by magnetron sputtering. The substrate material is selected to include a first substrate layer 302 , a second substrate layer 305 , a third substrate layer 309 , and a fourth substrate layer 312 .

[0076] In the above-mentioned multi-spectral stealth skin 3, the preparation process of the environmental mimicry film 306 includes:

[0077] S1 polydimethylsiloxane polydimethylsiloxane and SE1700 curing agent in a mass ratio of 10: 1 after stirring to form a glue, and then the glue and thermochromic capsules in a mass ratio of 10: 1 mixed;

[0078] S2. Place the mixture in S1 in an internal vacuum chamber, evacuate the chamber to a vacuum level of <3.0 × 10-3 Pa, and allow to stand for 30 minutes.

[0079] S3. The vacuum chamber was restored to normal pressure and the mixture was removed. The mixture was then poured into the coaxial mold and the mimetic film mold, respectively, and then the mold was placed in an 80°C oven for 2h;

[0080] S4. After removing the mold, demould it and use a vector network analyzer to test the electromagnetic parameters of the coaxial method sample. The measured electromagnetic parameters are as shown in the attached Figure 3 As shown;

[0081] This embodiment further provides an adaptive camouflage system, the adaptive camouflage system including the multi-spectral stealth skin 3, and the environment-adaptive multi-spectral compatible stealth skin system including:

[0082] For environmental recognition units Figure 1 In 11, the CMOS camera model selected is Daheng MER2-503-36U3C. By calling the software development kit provided by the camera manufacturer and using Python to write the camera class, the camera function call is completed.

[0083] For the control system unit 22, the Linux development board is ASUS tinker board 2s. The workflow is as shown in the attached Figure 4 As shown:

[0084] First, the modules used in the work are initialized and instantiated, including the initialization of the serial port and the instantiation of the camera class; then the parameters such as the exposure and gain of the camera are set; after completing the initialization of each module, the video stream is opened to obtain the current image, and the adaptive camouflage pattern generation algorithm is used to obtain a "0-1" logic matrix. After the matrix is ​​divided and reorganized, it is sent from the serial port to the FPGA control circuit in the format of a byte stream to complete the driving of the multi-spectral stealth skin 33.

[0085] The adaptive camouflage pattern generation algorithm process is summarized as follows:

[0086] 1) Calculate the visual complexity of the background image and obtain its complexity coefficient value to represent the richness of the details (i.e., high-frequency parts) contained in the current image;

[0087] 2) Dynamically select Gaussian blur parameters according to the complexity coefficient value to perform adaptive blurring on the background image; 3) For the blurred image, use the K-means clustering algorithm to perform patch segmentation and color replacement on the image to generate a camouflage pattern. The algorithm process framework is shown in the attached figure. Figure 5 shown.

[0088] For the multi-spectral stealth skin 33, infrared stealth is achieved by using a low-infrared emissive layer to block internal infrared wave emission and external infrared wave absorption, thereby preventing infrared detectors from detecting the target. For radar stealth, microwaves are converted into heat by the three central microwave loss layers through resonance absorption and dielectric loss, thereby suppressing microwave reflection and making them undetectable by radar, thus achieving radar stealth.

[0089] Visible light stealth first relies on the environmental recognition unit Figure 1 11 obtains background information, and then changes the temperature of the silicone rubber heating plate 314 through the control system unit 22, and finally the environmental mimicry film 306 fits a color similar to the background, thereby realizing environmental mimicry, that is, visible light invisibility.

[0090] Example 2:

[0091] Example 2 is similar to Example 1, except that the material selection of the multi-spectral stealth skin 3 is different, specifically including:

[0092] The multi-spectral stealth skin 3 uses a periodic array of tin antimony oxide thin film with a square resistance of 5Ω / sq as the infrared wave interception layer 301 and an air dielectric layer 303 at its bottom as the low infrared emission layer; a block-shaped tin antimony oxide thin film with a square resistance of 120Ω / sq is used as the first microwave loss layer 304, the second microwave loss layer 308, and a block-shaped tin antimony oxide thin film with a square resistance of 220Ω / sq is used as the third microwave loss layer 311, which is bonded to the first foam dielectric layer 307, the second foam dielectric layer 310, and the third foam dielectric layer 313 as the microwave absorption layer. The foam material is expandable polyethylene; thermochromic capsules that can change from grass green to khaki at 31°C are used together with polydimethylsiloxane. The environmental mimicry film 306 prepared by the injection molding process is used as the visible light stealth layer; the graphene heating plate is selected as the heating layer 314, and the infrared wave intercepting layer 301 is prepared on the first substrate layer 302 by using the photolithography process and the dry etching process; the first microwave loss layer 304, the second microwave loss layer 308 and the third microwave loss layer 311 are fixed on the second substrate layer 305, the third substrate layer 309 and the fourth substrate layer 312 respectively by using the laser etching process; the multi-spectral stealth skin in the present invention is prepared by preparing each layer structure separately, and then bonding each prepared film layer to the adjacent functional layer by a high-transmittance adhesive to complete the assembly of the skin.

[0093] The thickness of the air medium layer 303 is 0.5-2 mm; the thickness of the foam medium layer 307, the foam medium layer 310, and the foam medium layer 313 is 1 mm;

[0094] The antimony tin oxide thin film is deposited on a substrate with a thickness of 0.125 mm by magnetron sputtering. The substrate material is selected to include a first substrate layer 302 , a second substrate layer 305 , a third substrate layer 309 , and a fourth substrate layer 312 .

[0095] In the above-mentioned multi-spectral stealth skin 3, the preparation process of the environmental mimicry film 306 includes:

[0096] S1 polydimethylsiloxane polydimethylsiloxane and SE1700 curing agent in a mass ratio of 10: 1 after stirring to form a glue, and then the glue and thermochromic capsules in a mass ratio of 5: 1 mixed;

[0097] S2. Place the mixture in S1 in an internal vacuum chamber, evacuate the chamber to a vacuum level of <3.0 × 10-3 Pa, and allow to stand for 30 minutes.

[0098] S3. The vacuum chamber was restored to normal pressure and the mixture was removed. The mixture was then poured into the coaxial mold and the mimetic film mold, respectively, and then the mold was placed in an 80°C oven for 2h;

[0099] S4. Take out the mold and demould.

[0100] Example 3:

[0101] Example 2 is similar to Example 1, except that the material selection of the multi-spectral stealth skin 3 is different, specifically including:

[0102] The multi-spectral stealth skin 3 uses a periodic array aluminum-doped zinc oxide film with a square resistance of 12Ω / sq as the infrared wave interception layer 301 and an air dielectric layer 303 at its bottom as the low infrared emission layer; a block-shaped antimony tin oxide film with a square resistance of 180Ω / sq is used as the first microwave loss layer 304, the second microwave loss layer 308, and a block-shaped aluminum-doped zinc oxide film with a square resistance of 280Ω / sq is used as the third microwave loss layer 311, which is bonded to the first foam dielectric layer 307, the second foam dielectric layer 310, and the third foam dielectric layer 313 as the microwave absorption layer. The foam material is expandable polyethylene; thermochromic capsules that can change from grass green to khaki at 31°C are used together with polydimethylsiloxane. An environmental mimicry film 306 made of methylsiloxane through an injection molding process serves as a visible light stealth layer; a ceramic heating plate is selected as the heating layer 314, and the infrared wave intercepting layer 301 is prepared on the first substrate layer 302 by using a photolithography process and a dry etching process; the first microwave loss layer 304, the second microwave loss layer 308 and the third microwave loss layer 311 are respectively fixed on the second substrate layer 305, the third substrate layer 309 and the fourth substrate layer 312 by using a laser etching process; the multi-spectral stealth skin in the present invention is assembled by preparing each layer structure separately, and then bonding each prepared film layer to the adjacent functional layer through a highly light-transmitting adhesive.

[0103] The thickness of the air medium layer 303 is 2 mm; the thickness of the foam medium layer 307, the foam medium layer 310, and the foam medium layer 313 is 4 mm;

[0104] The aluminum-doped zinc oxide film is deposited on a substrate with a thickness of 0.125 mm by magnetron sputtering. The substrate material is selected to include a first substrate layer 302 , a second substrate layer 305 , a third substrate layer 309 , and a fourth substrate layer 312 .

[0105] In the above-mentioned multi-spectral stealth skin 3, the preparation process of the environmental mimicry film 306 includes:

[0106] S1 polydimethylsiloxane polydimethylsiloxane and SE1700 curing agent in a mass ratio of 10: 1 after stirring to form a glue, and then the glue and thermochromic capsules in a mass ratio of 10: 1 mixed;

[0107] S2. Place the mixture in S1 in an internal vacuum chamber, evacuate the chamber to a vacuum level of <3.0 × 10-3 Pa, and allow to stand for 30 minutes.

[0108] S3. The vacuum chamber was restored to normal pressure and the mixture was removed. The mixture was then poured into the coaxial mold and the mimetic film mold, respectively, and then the mold was placed in an 80°C oven for 2h;

[0109] S4. Take out the mold and demould.

[0110] The performance test of the multi-spectral stealth skin 3 prepared in the above embodiment 1 of the present invention is carried out, specifically including:

[0111] Infrared stealth performance test (infrared emissivity):

[0112] According to Kirchhoff's law, under equilibrium conditions, emissivity is equal to absorptivity. Therefore, the infrared emissivity is calculated by measuring the transmission and reflection spectra of the skin using a Fourier infrared spectrometer (Bruker INVENIO-S). The experimental test results are shown in the attached figure. Figure 7 As shown, in the infrared band of 3-14μm, the average emissivity is 0.227.

[0113] Radar stealth performance test (reflection coefficient, angle stability):

[0114] The microwave absorption characteristics of the sample were measured in a microwave anechoic chamber using an AV3655 stealth target radar cross section tester. Two pairs of broadband horn antennas with operating frequencies of 2-18 GHz and 18-40 GHz were used for measurement. The simulation results are compared with the experimental test results. Figure 8 As shown in the figure, in the radar band of 2.53-34.56GHz, the reflection coefficient is less than -10dB, which means that the microwave absorption rate exceeds 90%. The angle stability is measured using the arch method. Under TE and TM polarization, the angle stability of ±45° and ±60° can be maintained respectively. The results are shown in the attached figure. Figure 9 , Figure 10 shown.

[0115] Visible light stealth performance test (environmental mimicry performance):

[0116] The multi-spectral compatible stealth skin system was placed in grassland and desert environments for environmental mimicry performance testing. After the color change stabilized, the mimicry conditions in the two environments were as shown in the attached figure. Figure 11 and Figure 12 As shown, it can be observed that the system has a good mimicry effect.

[0117] The above embodiments further demonstrate that the present invention provides a multispectral stealth skin 3 and an environmentally adaptive multispectral compatible stealth skin system. This system can achieve a low infrared emissivity of 0.227, broadband microwave absorption (>90%) in the 2.53-34.56 GHz range, and adaptive visible light stealth in environments such as grasslands and deserts, thus possessing multispectral adaptive stealth capabilities. Compared to the background art Chinese patent CN117471404A, which discloses an adaptive camouflage skin electronic device and an adaptive stealth system, the design concept of this invention is to place the adaptive color-changing layer at the bottom, which to some extent limits the infrared-radar stealth performance. Its infrared emissivity is higher than the 0.227 of the present invention, and its absorption effect is not strong in the low frequency band of 2-10 GHz. In terms of adaptive system construction, the ambient light sensor used for background recognition can only return single color data, which is powerless in complex color environments. However, the CMOS camera used in the present invention can directly return the complete color information of the background image, thus possessing the potential for pixel-level visible light stealth and possessing strong adaptability.

[0118] In the description of the embodiments of the present application, it should be noted that in the description of the present application, terms such as "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0119] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0120] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A multi-spectral stealth skin, characterized in that: The multi-spectral stealth skin (3) includes a low infrared emission layer, a microwave absorption layer, and a heating layer (314) connected in sequence from top to bottom, wherein the microwave absorption layer includes a visible light stealth layer, and the visible light stealth layer is an environmental mimicry film (306) prepared by an injection molding process of thermochromic capsules and polydimethylsiloxane; The microwave absorption layer comprises, connected in sequence from top to bottom, a first microwave loss layer (304), a second base layer (305), an environmental mimic film (306), a first foam medium layer (307), a second microwave loss layer (308), a third base layer (309), a second foam medium layer (310), a third microwave loss layer (311), a fourth base layer (312), and a third foam medium layer (313); The materials of the first microwave loss layer (304), the second microwave loss layer (308) and the third microwave loss layer (311) are one of indium tin oxide, antimony tin oxide and aluminum-doped zinc oxide, or a composite material of indium tin oxide, antimony tin oxide and aluminum-doped zinc oxide; The square resistance of the first microwave loss layer (304) and the second microwave loss layer (308) is 220-280Ω / sq; the square resistance of the third microwave loss layer (311) is 120-180Ω / sq; The low infrared emission layer comprises an infrared wave intercepting layer (301), a first base layer (302), and an air dielectric layer (303) connected in sequence from top to bottom. The infrared wave intercepting layer (301) is made of one of indium tin oxide, antimony tin oxide, and aluminum-doped zinc oxide, and the square resistance of the infrared wave intercepting layer (301) is 5-12Ω / sq. The first base layer (302) is a PET base, and the air dielectric layer (303) is obtained by laser engraving on the surface of the first base layer (302).

2. The multi-spectral stealth skin according to claim 1, characterized in that: The first foam medium layer (307), the second foam medium layer (310), and the third foam medium layer (313) are made of polymethacrylimide, expandable polyethylene, or a composite material of polymethacrylimide and expandable polyethylene; the second base layer (305), the third base layer (309), and the fourth base layer (312) are PET bases.

3. The multi-spectral stealth skin according to claim 1, characterized in that: The infrared wave intercepting layer (301) is fixed on the first base layer (302) by means of a photolithography process and a dry etching process; the first microwave loss layer (304), the second microwave loss layer (308), and the third microwave loss layer (311) are respectively fixed on the second base layer (305), the third base layer (309), and the fourth base layer (312) by means of a laser etching process.

4. The multi-spectral stealth skin according to claim 1, characterized in that: The heating layer (314) is one of a graphene heating plate, a silica gel heating plate and a ceramic heating plate, or a heating plate made of a composite material of graphene, silica gel and ceramic.

5. The multi-spectral stealth skin according to claim 1, characterized in that: The preparation method of the environmental mimicry film comprises: S1 polydimethylsiloxane and SE1700 curing agent in a mass ratio of 10:1 were stirred to form a glue, and then the glue and thermochromic capsules were mixed in a mass ratio range of 5:1 to 10:1; S2. Place the mixture in S1 in an internal vacuum chamber, evacuate the chamber to a vacuum level of less than 3.0 × 10-3 Pa, and allow to stand for 30 minutes. S3. The vacuum chamber was restored to normal pressure and the mixture was removed. The mixture was then poured into the coaxial mold and the mimetic film mold, respectively. The molds were then placed in an 80°C oven for 2 hours. S4. The mold is removed and demoulded to obtain an environmental mimicking film (306).

6. A multi-spectral stealth skin adaptive camouflage system, characterized by: The adaptive camouflage system comprises: an environment recognition unit (1), a control system unit (2), and a multi-spectral stealth skin (3) according to any one of claims 1 to 5; The environment recognition unit (1) is connected to the control system unit (2) and is used to collect an environment background image and convert it into an electrical signal to be input into the control system unit (2); The control system unit (2) is connected to the multi-spectral stealth skin (3) and is used to receive the electrical signal output by the environment recognition unit and perform analysis and processing, and convert the electrical signal into a control information source of the multi-spectral stealth skin (3) and input it into the multi-spectral stealth skin (3).

7. The multi-spectral stealth skin adaptive camouflage system according to claim 6, characterized in that: The working process of the adaptive camouflage system includes: Visible light stealth: Background information is obtained through the environment recognition unit (1), and then the background information is converted into an electrical signal and input into the control system unit (2). The control system unit (2) changes the temperature of the heating layer (314) of the multi-spectral stealth skin (3), and then the environment mimicry film (306) is fitted with a color similar to the background, thereby achieving environment mimicry, that is, visible light stealth; Radar stealth: Each microwave loss layer in the microwave absorption layer of the multi-spectral stealth skin (3) converts microwaves into heat by means of resonance absorption and dielectric loss, thereby suppressing the reflection of microwaves and making it impossible for radar to detect, thereby achieving radar stealth; Infrared stealth: The low infrared emissive layer blocks the emission of internal infrared waves and the absorption of external infrared waves, thereby avoiding detection of the target by infrared detectors.

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