Visible and infrared dual-band stealth material and preparation method thereof

Abstract

The invention provides a visible and infrared dual-band stealth material and a preparation method thereof. The visible and infrared dual-band stealth material comprises a thermochromic ink layer, a transparent conductive layer, a quartz glass substrate and a phase change material layer which are sequentially arranged, wherein the phase change material layer is arranged in a grid shape; and the material of the phase change material layer is selected from VO2 or sulfur germanium antimony tellurium. The surface phase-change material layer of the stealth material is arranged in a grid shape, the color-changing ink layer at the bottom can be directly seen by naked eyes, camouflage patterns are formed on the color-changing ink layer through printing, and the dynamic visible light camouflage function is achieved; when the top layer VO2 or chalcogenide germanium antimony tellurium is in a phase transformation state, the infrared reflectivity of the top layer VO2 or chalcogenide germanium antimony tellurium becomes high, the emissivity becomes low, and therefore the dynamic infrared camouflage function is achieved. Joule heat can be generated when voltage is applied to the transparent conductive layer, and the heat enables the color of the color-changing ink layer to change, so that the visible light camouflage function can be adapted to various scenes. Visible and infrared dual-band stealth can be achieved, dynamic stealth can also be achieved, and the application requirements of multiple spectrums and multiple scenes are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of stealth materials, and in particular relates to a visible and infrared dual-band stealth material and a preparation method thereof. Background Art

[0002] There has always been a strong demand for advanced camouflage and stealth technologies in the field or on the battlefield. With advances in detection technology, the use of multispectral detection is becoming increasingly common. This means that camouflage and stealth technologies must possess multispectral properties, meaning they must be able to operate not only in a single wavelength band but also in multiple wavelength bands. Common camouflage patterns are typically invisible in the visible light band, but not in infrared thermal imagers. Existing multi-band (or multispectral) stealth systems are typically static and cannot adapt to changes in the background, leaving them vulnerable to detection in practical applications. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a visible and infrared dual-band stealth material and a preparation method thereof. The stealth material has a camouflage color in visible light camouflage and is applicable both during the day and at night.

[0004] The present invention provides a visible and infrared dual-band stealth material, comprising a thermochromic ink layer, a transparent conductive layer, a quartz glass substrate, and a phase change material layer arranged in a grid shape.

[0005] The material of the phase change material layer is selected from VO2 or chalcogenide germanium antimony telluride.

[0006] Preferably, the side length of the cells in the grid pattern is 0.1 to 2 mm, and the cell spacing is 0.001 to 0.2 mm.

[0007] Preferably, the grid shape is a periodic rectangle or a periodic parallelogram or a non-periodic structure.

[0008] Preferably, the color changing temperature of the thermochromic ink layer is 20-70°C.

[0009] Preferably, the transparent conductive layer is connected to a power source for generating Joule heat;

[0010] The voltage of the power supply is 1~30V.

[0011] Preferably, the transparent conductive layer is an ITO film coated with silver paste on both sides.

[0012] Preferably, the thickness of the thermochromic ink layer is 5 to 500 microns;

[0013] The thickness of the transparent conductive layer is 50 to 500 nm;

[0014] The thickness of the quartz glass substrate is 0.01 to 10 mm;

[0015] The thickness of the phase change material layer is 20-500 nm.

[0016] Preferably, one or more dielectric layers are provided between the quartz glass substrate and the phase change material layer;

[0017] The thickness of each dielectric layer is 10 to 1000 nm;

[0018] The material of the dielectric layer is selected from one or more of ZnO, Al2O3, Si, Ge, HfO2 and ZnS.

[0019] The present invention provides a method for preparing the visible and infrared dual-band stealth material according to the above technical solution, comprising the following steps:

[0020] Sputtering and depositing a phase change material on one surface of a pre-treated quartz glass substrate, annealing, and then laser etching to form a phase change material layer arranged in a grid pattern;

[0021] sputtering a transparent conductive layer on the other surface of the pretreated quartz glass substrate;

[0022] Then, ink is printed on the transparent conductive layer and cured to obtain a visible and infrared dual-band stealth material.

[0023] Preferably, the annealing temperature is 350-550° C., and the annealing time is 0.5-2 h;

[0024] The parameters adopted for the laser etching include: laser power of 5 to 10 W, frequency of 100 to 200 kHz, and pulse width of 10 to 50 ns.

[0025] The present invention provides a visible and infrared dual-band stealth material, comprising a thermochromic ink layer, a transparent conductive layer, a quartz glass substrate, and a grid-like phase-change material layer. The phase-change material layer is selected from VO2 or sulfide-based germanium, antimony, and tellurium. The surface phase-change material layer of the stealth material provided by the present invention is arranged in a grid-like pattern with a hollow structure. The bottom color-changing ink layer is directly visible to the naked eye. The color-changing ink layer is printed to form a camouflage pattern, thereby providing dynamic visible light camouflage. When the top layer of VO2 or sulfide-based germanium, antimony, and tellurium is in a phase-change state, its infrared reflectivity increases and its emissivity decreases. According to the Stefan-Boltzmann law, its surface radiation energy decreases, thus providing dynamic infrared camouflage. When voltage is applied to the transparent conductive layer, Joule heat is generated, which changes the color of the color-changing ink layer, making its visible light camouflage function adaptable to a variety of scenarios. At the same time, the presence of the phase-change material layer's grid surface modulates the emissivity not only by Joule heat but also by the grid's duty cycle, thereby forming an infrared camouflage pattern. Its infrared thermal imaging pattern and thermal radiation energy meet the requirements of blending in with the background. As a result, the stealth material provided by this application not only achieves dual-band stealth in the visible and infrared, but also achieves dynamic stealth, meeting the application requirements of multi-spectrum and multi-scenario applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the three-dimensional structure of the visible and infrared dual-band stealth material provided in Example 1 of the present invention, wherein 1 is a grid-shaped phase change material layer VO2, 2 is a quartz glass substrate, 3 is a transparent conductive layer ITO, and 4 is a thermochromic ink layer;

[0027] Figure 2 This is a VO2 microarray structure. The side length of the glass sheet is 4 cm. The yellow unit cell is f v为 50%, red cells f v is 75%, blue cell f v is 100%;

[0028] Figure 3 A schematic diagram of the two-dimensional structure of a visible and infrared dual-band stealth material provided in Example 1 of the present invention;

[0029] Figure 4 Schematic diagram of the three-dimensional structure of the visible and infrared dual-band stealth material provided in Example 2 of the present invention, wherein 1 is a grid-shaped phase change material layer VO2, 2 is Ge, 3 is a transparent conductive layer ITO, 4 is a quartz glass substrate, 5 is a transparent conductive layer ITO, and 6 is a thermochromic ink layer;

[0030] Figure 5 This is a schematic diagram of the two-dimensional structure of a visible and infrared dual-band stealth material provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0031] The present invention provides a visible and infrared dual-band stealth material, comprising a thermochromic ink layer, a transparent conductive layer, a quartz glass substrate, and a phase change material layer arranged in a grid shape.

[0032] The material of the phase change material layer is selected from VO2 or chalcogenide germanium antimony telluride.

[0033] This stealth material offers visible light camouflage, suitable for both day and night use. For outer space applications where black is essential, a black temperature-variable ink can be used. The phase-change material layer is arranged in a grid pattern, allowing not only adjustable emissivity but also adjustable patterns, resulting in different colors and images displayed by infrared thermal imaging detectors. This allows for use in complex environments with constantly changing background temperatures and materials. Compared to precious metals, VO2 is inexpensive, making it suitable for large-scale application.

[0034] The visible and infrared dual-band stealth material provided by the present invention includes a phase change material layer arranged in a grid shape; the material of the phase change material layer is selected from VO2 or sulfur-based germanium antimony telluride. The phase change material layer arranged in a grid shape has a hollow portion, which allows a portion of visible light to pass through, and the surface presents a certain degree of transparency. The grid shape is a periodic rectangle or a periodic parallelogram or a non-periodic structure. The VO2 has phase change characteristics. Below 341K, it is in a semiconductor state with low electrical conductivity and can transmit infrared light to a certain extent; above or equal to 341K, it is in a metallic state with high electrical conductivity, low infrared light transmittance and high reflectivity, and has low emissivity. The phase change of the sulfur-based germanium antimony telluride is switching between an amorphous state and a crystalline state.

[0035] The visible and infrared dual-band stealth material provided by the present invention comprises a quartz glass substrate in contact with a phase change material layer arranged in a grid shape. The quartz glass substrate can support the phase change material layer and transmit broadband light.

[0036] The visible and infrared dual-band stealth material provided by the present invention preferably comprises one or more dielectric layers disposed between the quartz glass substrate and the phase-change material layer; each dielectric layer has a thickness of 10 to 1000 nm, and the dielectric layer is made of one or more materials selected from ZnO, Al2O3, Si, Ge, HfO2, and ZnS. In a specific embodiment, the dielectric layer is a Ge dielectric thin film with a thickness of 400 to 500 nm.

[0037] The visible and infrared dual-band stealth material provided by the present invention includes a transparent conductive layer in contact with a quartz glass substrate; the transparent conductive layer is indium-doped tin oxide (ITO), and more specifically, the transparent conductive layer is an ITO film coated with silver paste on both sides.

[0038] The transparent conductive layer described in the present invention is connected to a power source to generate Joule heat. In addition to the power source, it may also include circuit components such as a temperature sensor and a controller. This invention utilizes precise temperature control of the transparent conductive layer, between room temperature and 70°C (room temperature, i.e., the state when no voltage is applied), to drive VO2 or the chalcogenide-based germanium antimony telluride to switch between insulator and metallic states, thereby regulating its thermal imaging effect. This also drives the color change of the thermochromic ink layer, thereby controlling its visual effect.

[0039] The present invention provides a dual-band visible and infrared stealth material comprising a thermochromic ink layer in contact with a transparent conductive layer. The thermochromic ink layer exhibits different color effects at different temperatures. The thermochromic ink is preferably selected to have a temperature close to the phase transition temperature of VO2.

[0040] The present invention combines the phase change characteristics of VO2 or sulfur-based germanium antimony tellurium with thermochromic coatings to achieve dual-band camouflage through a layered structure.

[0041] In the present invention, the thickness of the thermochromic ink layer is 5 to 500 microns, specifically 5 microns, 10 microns, 15 microns, 20 microns, 25 microns, 30 microns, 35 microns, 40 microns, 45 microns, 50 microns, 55 microns, 60 microns, 65 microns, 70 microns, 75 microns, 80 microns, 85 microns, 90 microns, 95 microns, 100 microns, 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 160 microns, 170 microns, 180 microns, 190 microns, 200 microns, 210 microns, 220 microns, 230 microns, 240 microns, 250 microns, 260 microns, 270 microns, 280 microns, 290 microns, 300 microns, 310 microns, 320 microns, 330 microns, 340 microns, 350 microns, 360 microns, 370 microns, 380 microns, 390 microns, 400 microns, 410 microns, 420 microns, 430 microns, 440 microns, 450 microns, 460 microns, 470 microns, 480 microns, 490 microns, 500 microns, 510 microns, 510 microns, 520 microns, 520 microns 100 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, 360 μm, 370 μm, 380 μm, 390 μm, 400 μm, 410 μm, 420 μm, 430 μm, 440 μm, 450 μm, 460 μm, 470 μm, 480 μm, 490 μm, or 500 μm;

[0042] The thickness of the transparent conductive layer in the present invention is 50 to 500 nm; specifically, it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm, 410 nm, 420 nm, 430 nm, 440 nm, 450 nm, 460 nm, 470 nm, 480 nm, 490 nm or 500 nm.

[0043] The thickness of the quartz glass substrate of the present invention is 0.01 to 10 mm; specifically, it can be 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6 mm, 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, 9.0 mm, 9.5 mm or 10 mm.

[0044] The thickness of the phase change material layer in the present invention is 20 to 500 nm; specifically, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm m, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm , 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm or 500nm.

[0045] The stealth material provided by the present invention features a phase-change material layer arranged in a grid-like, hollowed-out structure. The thermochromic ink layer at the bottom is directly visible to the naked eye. This color-changing ink layer is printed to form a camouflage pattern, thus providing basic visible light camouflage functionality. When the phase-change material layer is in a metallic state, its infrared reflectivity is high and its emissivity is low. According to the Stefan-Boltzmann law, its surface radiation energy is low, thus providing infrared camouflage functionality. When a voltage is applied to the transparent conductive layer, Joule heat is generated, which changes the color of the color-changing ink layer, enabling the visible light camouflage function to be adapted to various scenarios. Furthermore, the surface emissivity of VO2 or the sulfur-based germanium antimony tellurium is regulated not only by Joule heat but also by the grid duty cycle, ensuring that its infrared thermal imaging pattern and thermal radiation energy blend seamlessly with the background. This enables dual-band stealth in both the visible and infrared bands, as well as dynamic stealth, meeting the requirements of multi-spectral and multi-scenario applications.

[0046] The present invention provides a method for preparing the visible and infrared dual-band stealth material described in the above technical solution, comprising the following steps:

[0047] Sputtering and depositing a phase change material on one surface of a pre-treated quartz glass substrate, annealing, and then laser etching to form a phase change material layer arranged in a grid pattern;

[0048] sputtering a transparent conductive layer on the other surface of the pretreated quartz glass substrate;

[0049] Then, ink is printed on the transparent conductive layer and cured to obtain a visible and infrared dual-band stealth material.

[0050] The present invention preferably uses acetone and ethanol ultrasonic cleaning in sequence to remove oil stains on the surface of the quartz glass substrate, then rinses it with deionized water, and finally blows it dry with nitrogen to obtain a pretreated quartz glass substrate.

[0051] The present invention sputters and deposits a phase change material on one surface of a pretreated quartz glass substrate; specifically, the vacuum is drawn until the pressure of the device is about 1×10 -4 Pa, turn on the DC sputtering power supply, and pre-sputter the target with pure Ar gas for 5 to 10 minutes to remove the surface oxide layer and contaminants. Introduce O2, adjust the Ar / O2 ratio to a certain value (85 to 99): (15 to 1), the power is 300 to 400W, and the temperature is room temperature; start the sputtering power supply and begin deposition at a sputtering rate of 10 to 25nm / min. The film thickness is controlled by the sputtering time. After deposition is completed, turn off the sputtering power supply and gas, and wait for the substrate to cool to room temperature before removing it.

[0052] After taking out, annealing is performed; the annealing temperature is 350-550°C, specifically 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C or 550°C; the annealing time is 0.5-2h, specifically 30min, 35min, 40min, 45min, 50min, 55min, 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min, 100min, 105min, 110min, 115min or 120min.

[0053] The present invention uses a laser etching machine to form a grid-like phase-change material layer. The substrate, with the phase-change material thin film formed on its surface, is fixed to a moving platform, and the phase-change material thin film is scribed using a laser etching machine. Laser scribing parameters include: laser power of 5 to 10W, frequency of 100 to 200kHz, and pulse width of 10 to 50ns. Within each grid, a certain area of ​​VO2 or chalcogenide-based germanium antimony telluride is removed by laser scribing to create grids with various fill ratios. The fill ratios range from 50 to 100%, specifically including combinations of 50%, 75%, and 100%. Different fill ratios correspond to different equivalent emissivities. Each pattern has a different emissivity above the phase transition temperature of VO2 or chalcogenide-based germanium antimony telluride, but the emissivity of all patterns is nearly identical below the phase transition temperature. Furthermore, because a portion of the film is removed, the overall visible light transmittance is improved, making the device more transparent.

[0054] The present invention sputters a transparent conductive layer on the other surface of the pretreated quartz glass substrate; the transparent conductive layer is preferably an ITO film; the present invention preferably applies silver paste on the left and right sides of the ITO film; after curing, a conductive copper foil is attached, and the copper foil is connected to an external power supply. At the same time, a temperature sensor is placed on the surface of the transparent conductive layer and connected to a controller to achieve temperature control and real-time feedback, thereby forming an ITO heating structure.

[0055] The present invention then prints ink on the transparent conductive layer and cures it to obtain a visible and infrared dual-band stealth material. The color of the printed ink in the present invention can be dark green, light green, beige, sandy, light brown, dark brown, etc. The present invention ensures that the color change performance and adhesion of the ink reach the optimal state by adjusting the drying temperature and time. The present invention adopts ultraviolet curing or thermal curing for shaping. Conditions for ultraviolet curing: use an LED-UV light source, set the light intensity to 100-3000mW / cm2, and the irradiation time is 5-30s. Conditions for thermal curing: use medium-temperature curing, set the temperature to 80-150°C, the heating rate is 10-20°C / min, and the time is 30-180min.

[0056] The stealth material prepared by the above method provided by the present invention can not only achieve dual-band stealth in the visible and infrared bands, but also achieve dynamic stealth, meeting the application requirements of multi-spectrum and multi-scene.

[0057] In order to further illustrate the present invention, a visible and infrared dual-band stealth material and a preparation method thereof provided by the present invention are described in detail below in combination with embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0058] Example 1

[0059] Step (1) Cleaning the substrate: Select a quartz plate of appropriate size, first use acetone and ethanol organic solvents to ultrasonically clean it to remove surface oil, then rinse it with deionized water, and finally blow it dry with nitrogen.

[0060] Step (2) Sputtering deposition process: vacuum the device until the pressure is about 1×10 -4 Pa, turn on the DC sputtering power supply, and pre-sputter the target with pure Ar gas for 5-10 minutes to remove the surface oxide layer and contaminants. Introduce O2, adjust the Ar / O2 ratio to a certain value of 85-99 / 10-1, the power is 300-400W, and the temperature is room temperature. Start the sputtering power supply and begin deposition at a sputtering rate of 15-25nm / min. The film thickness is controlled by the sputtering time. After deposition is completed, turn off the sputtering power supply and gas, and wait for the substrate to cool to room temperature before removing it. The prepared film is annealed at 500°C and a low pressure of 10Pa for 1 hour to form a VO2 thin film.

[0061] Step (3) Fabrication of VO2 microarray structure: The VO2 pattern is realized by a laser etcher, the substrate is fixed on a moving platform, and a laser film engraving machine is used to scribe the film. Adjust the parameters of the laser engraving machine, set the laser power to 5-10W, the frequency to 100-200kHz, and the pulse width to 10-40ns, turn on the laser etcher switch, and perform etching. The cell side length in the grid structure pattern is 0.1-2mm, and the cell spacing is 0.01-0.2mm. In each cell, 0.1mm is etched by laser with a period of 0.142mm to achieve a VO2 filling rate of 50%; 0.1mm is etched with a period of 0.2mm to achieve a VO2 filling rate of 75%; and no etching achieves a VO2 filling rate of 100%.

[0062] Step (4) preparing an ITO film: sputtering an ITO film on the other side of the quartz glass substrate, coating both sides of the ITO with silver paste, pasting a conductive copper foil after curing, connecting the copper foil to an external power supply, and placing a temperature sensor on the ITO surface and connecting it to a controller to achieve temperature control and real-time feedback, thereby forming an ITO heating structure.

[0063] Step (5) Printing ink: Select temperature-sensitive color-changing inks of dark green, light green, beige, etc., and print them on the ITO heating structure to form a visually visible camouflage pattern. Place the sample in an oven and bake it according to the drying and curing conditions of the ink to dry and cure the ink. The curing temperature is 80°C and the time is 30 minutes to ensure that the color-changing performance and adhesion of the ink reach the optimal state.

[0064] Example 2

[0065] Step (1) Cleaning the quartz glass substrate: Ultrasonic cleaning was performed with deionized water, anhydrous ethanol, and acetone for 15 minutes in sequence, and the residual solution was finally removed with deionized water. The substrate was blown dry with high-purity nitrogen or dried in a thermoelectric blower drying oven at 30-60°C.

[0066] Step (2) magnetron sputtering coating: After the substrate is cleaned, it is placed on the substrate table. Magnetron sputtering is used to prepare ITO film, Ge dielectric layer film, and VO2 film in sequence. The thickness of the ITO film is 250-300nm, the thickness of the Ge dielectric layer film is 400-450nm, and the thickness of the VO2 film is 20-50nm. Among them, the ITO film is prepared by pulsed DC sputtering, with a sputtering power of 100-200W, an oxygen partial pressure (O2 / Ar+O2 is 5%-7%), and a pressure of 0.1-0.25Pa; the Ge film is deposited by radio frequency sputtering, with only Ar introduced, the sputtering power is set (100-200W), and the pressure is maintained at 0.1-5Pa during sputtering; the vanadium target is sputtered and the oxygen partial pressure is controlled to obtain the VO2 film, the metal vanadium target is installed, and the vacuum is evacuated to 1×10 -3Pa or less to reduce the impact of residual gas on the coating quality. Introduce an appropriate amount of argon Ar into the sputtering chamber as sputtering gas, and at the same time introduce a certain proportion of O2 as reaction gas as needed, control the oxygen partial pressure (O2 / Ar+O2: 2~4.5%), adjust the gas flow and pressure, and stabilize the gas pressure in the sputtering chamber within a suitable range, usually 0.1~10Pa. Turn on the magnetron sputtering power supply and sputter the vanadium target with a DC power of 100~300W. The sputtering time is determined according to the thickness of the required film. After sputtering is completed, turn off the sputtering power supply and gas valve. After the gas pressure in the sputtering chamber returns to normal pressure, open the sputtering chamber door, take out the sample, and place the sample in a vacuum annealing furnace or atmosphere annealing furnace. Set the temperature to 400~500℃ and the annealing time to 0.5~1.5 hours.

[0067] Step (3) Fabrication of array structure: Use a laser engraving machine to prepare microstructures on the VO2 surface, adjust the laser engraving machine parameters, laser power 5-10W, frequency 100-200kHz, pulse width 10-40ns, turn on the laser engraving machine switch, and etch the periodic pattern into a parallelogram. By designing different side lengths and line widths, different filling rates are achieved, with filling rates of 50%, 75%, and 100%, respectively. Etching 0.2mm, period 0.682mm, achieves a VO2 50% filling rate; etching 0.2mm, period 1.49mm, achieves a VO2 75% filling rate; no etching achieves a VO2 100% filling rate. Different filling rates correspond to different equivalent emissivities. The emissivities of each pattern are different when above the VO2 phase transition temperature, but the emissivities of all patterns are almost the same when below the phase transition temperature. At the same time, since part of the film layer is etched away, the overall visible light transmittance is improved, and the device becomes more transparent.

[0068] Step (4) preparing an ITO film: sputtering an ITO film on the other side of the quartz glass substrate, coating both sides of the ITO with silver paste, attaching a conductive copper foil to the surface of the silver paste after curing, connecting the copper foil to an external power supply, and placing a temperature sensor on the ITO surface and connecting it to a controller to achieve temperature control and real-time feedback, thereby forming an ITO heating structure;

[0069] Step (5) Printing ink: Select a temperature-variable ink with a temperature close to the VO2 phase transition temperature, in colors such as sand, light brown, and dark brown. Print on the ITO heating layer to form a visually visible camouflage pattern. Use thermal curing to set the pattern. The temperature is set at 120°C, the heating rate is 10°C / min, and the time is 30 minutes.

[0070] As can be seen from the above embodiments, the present invention provides a visible and infrared dual-band stealth material, comprising a thermochromic ink layer, a transparent conductive layer, a quartz glass substrate, and a phase-change material layer arranged in a grid pattern. The phase-change material layer is selected from VO2 or sulfide-based germanium antimony telluride. The surface phase-change material layer of the stealth material provided by the present invention is a hollowed-out grid-like structure. The bottom color-changing ink layer is directly visible to the naked eye. The color-changing ink layer is printed to form a camouflage pattern, thereby providing dynamic visible light camouflage. In Example 1, when the top layer of VO2 or sulfide-based germanium antimony telluride is in a phase-change state, its infrared reflectivity increases and its emissivity decreases. According to the Stefan-Boltzmann law, its surface radiation energy decreases, thus providing dynamic infrared camouflage. When a voltage is applied to the transparent conductive layer, Joule heating is generated. This heat changes the color of the color-changing ink layer, enabling its visible light camouflage function to be adapted to a variety of scenarios. The device is a negative differential device, meaning that as the temperature increases, the infrared emissivity decreases. In Example 2, the multilayer phase change structure forms a Fabry-Perot resonant cavity. When a voltage is applied to the transparent conductive layer, Joule heating is generated. When the top layer of the resonant cavity, VO2 or the chalcogenide germanium antimony telluride, is in a phase change state, its infrared reflectivity increases. The emissivity is amplified through resonance, making the device a positive differential device, meaning that as the temperature increases, the infrared emissivity increases accordingly. At the same time, the surface emissivity of the phase change material layer is regulated not only by Joule heating but also by the grid duty cycle, thereby forming an infrared camouflage pattern, so that its infrared thermal imaging pattern and thermal radiation energy meet the requirements of blending with the background. Therefore, the stealth material provided by this application can not only achieve dual-band stealth in the visible and infrared, but also achieve dynamic stealth, meeting the application requirements of multi-spectrum and multi-scenario.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A visible and infrared dual-band stealth material, characterized in that: It includes a thermochromic ink layer, a transparent conductive layer, a quartz glass substrate and a phase change material layer arranged in a grid shape. The material of the phase change material layer is selected from VO2 or chalcogenide germanium antimony telluride.

2. The visible and infrared dual-band stealth material with dynamically adjustable characteristics according to claim 1, characterized in that: The side length of the cells in the grid pattern is 0.1 to 2 mm, and the cell spacing is 0.001 to 0.2 mm.

3. The visible and infrared dual-band stealth material with dynamically adjustable characteristics according to claim 1, characterized in that: The grid shape is a periodic rectangle or a periodic parallelogram or a non-periodic structure.

4. The visible and infrared dual-band stealth material with dynamically adjustable characteristics according to claim 1, characterized in that: The color changing temperature of the thermochromic ink layer is 20-70°C.

5. The visible and infrared dual-band stealth material with dynamically adjustable characteristics according to claim 1, characterized in that: The transparent conductive layer is connected to a power source to generate Joule heat; The voltage of the power supply is 1~30V.

6. The visible and infrared dual-band stealth material with dynamically adjustable characteristics according to claim 1, characterized in that: The transparent conductive layer is an ITO film coated with silver paste on both sides.

7. The visible and infrared dual-band stealth material with dynamically adjustable characteristics according to claim 1, characterized in that: The thickness of the thermochromic ink layer is 5 to 500 microns; The thickness of the transparent conductive layer is 50 to 500 nm; The thickness of the quartz glass substrate is 0.01 to 10 mm; The thickness of the phase change material layer is 20-500 nm.

8. The visible and infrared dual-band stealth material with dynamically adjustable characteristics according to claim 1, characterized in that: One or more dielectric layers are provided between the quartz glass substrate and the phase change material layer; The thickness of each dielectric layer is 10 to 1000 nm; The material of the dielectric layer is selected from one or more of ZnO, Al2O3, Si, Ge, HfO2 and ZnS.

9. A method for preparing the visible and infrared dual-band stealth material according to claim 1, comprising the following steps: Sputtering and depositing a phase change material on one surface of a pre-treated quartz glass substrate, annealing, and then laser etching or photolithography to form a phase change material layer arranged in a grid pattern; sputtering a transparent conductive layer on the other surface of the pretreated quartz glass substrate; Then, ink is printed on the transparent conductive layer and cured to obtain a visible and infrared dual-band stealth material.

10. The preparation method according to claim 9, characterized in that The annealing temperature is 350-550° C., and the annealing time is 0.5-2 h; The parameters adopted for the laser etching include: laser power of 5 to 10 W, frequency of 100 to 200 kHz, and pulse width of 10 to 50 ns.

Images