Thermochromic intelligent dual-band infrared stealth film

Abstract

The utility model relates to a thermochromic intelligent dual-band infrared stealth film, and belongs to the technical field of infrared stealth films. In order to solve the problems that an existing infrared stealth material is complex in preparation process, high in cost and narrow in application range, the utility model provides a thermochromic intelligent dual-band infrared stealth film which sequentially comprises a ZnS material layer, a VO2 material layer, a Si material layer and an Ag substrate layer from top to bottom. The infrared stealth film disclosed by the utility model has the characteristic that the infrared emissivity is reduced along with the temperature rise, the emissivity of the film can be adaptively and reversibly adjusted according to the environment temperature change, the infrared stealth film has a stealth function of double infrared bands of 3-5 microns and 8-14 microns, and meanwhile, the infrared stealth film has relatively high emissivity in a non-infrared detection band of 5-8 microns, so that the infrared stealth effect is greatly improved. And the heat dissipation function of the stealth target in the wave band can be realized. The infrared stealth film disclosed by the utility model has the characteristics of simple structure and convenient preparation method, can cover the surface of a target in a large area, and is beneficial to large-scale popularization.

Description

Technical Field

[0001] The utility model belongs to the technical field of infrared stealth films, and in particular relates to a thermochromic intelligent dual-band infrared stealth film. Background Art

[0002] With the rapid development of infrared detector technology, infrared detection methods tend to be high-precision and diversified, which puts forward new and higher requirements for infrared stealth technology. According to the development status of infrared stealth technology, its development trend can be summarized into two aspects: one is to seek compatibility of stealth technologies in various bands, and the other is to improve existing stealth methods.

[0003] The invention patent with publication number CN113534315A, "An infrared stealth superstructure compatible with thermovariable emissivity and frequency-selective heat dissipation", mainly includes a number of electromagnetic resonance units arranged periodically on a substrate, each electromagnetic resonance unit includes an emissivity control layer and a dielectric layer stacked in sequence from bottom to top, and a number of metal columns periodically arranged on the dielectric layer; the emissivity control layer is made by embedding a phase change material in a metal layer stacked on the substrate. According to the characteristics of this infrared stealth metastructure material, although it can achieve modulated emissivity in the atmospheric transmission windows: 3-5μm and 8-14μm, and enhance thermal radiation in the atmospheric absorption band of 5-8μm to achieve the effect of active heat dissipation; but it also has certain defects: (1) The material structure is relatively complex. In the process of regulating the emissivity and frequency-selective thermal emission, it is necessary to strictly control parameters such as the diameter or side length, height and spacing of the metal columns. The regulation process is relatively complex and the modulation requirements are high, which has the defect of inconvenient regulation; (2) The metal columns in the structure are made of precious metals, which increases the manufacturing cost in the actual production and utilization process, which is not conducive to large-scale promotion and use; (3) In the manufacturing process of 3D metamaterial structures, there are generally problems such as complicated steps, high cost, and long time consumption. It is not easy to conform to the curved surface and it is difficult to meet the application conditions in actual complex situations.

[0004] Based on this, the field is in urgent need of infrared stealth materials with simple preparation process, low cost, suitable for more application scenarios, and capable of achieving multi-band compatibility and good heat dissipation performance. Summary of the invention

[0005] In order to solve the above-mentioned deficiencies in the prior art, the utility model provides a thermochromic intelligent dual-band infrared stealth film.

[0006] The technical solution of this utility model:

[0007] A thermochromic multi-band compatible infrared stealth film comprises, from top to bottom, a ZnS material layer, a VO2 material layer, a Si material layer and an Ag substrate layer.

[0008] Furthermore, the thickness of the ZnS material layer is 300-600 nm.

[0009] Furthermore, the thickness of the ZnS material layer is 600 nm.

[0010] Furthermore, the thickness of the VO2 material layer is 100-250 nm.

[0011] Furthermore, the thickness of the VO2 material layer is 200 nm.

[0012] Furthermore, the thickness of the Si material layer is not less than 1000 nm.

[0013] Furthermore, the thickness of the Ag substrate layer is not less than 200 nm.

[0014] Beneficial effects of the utility model:

[0015] The thermochromic multi-band compatible infrared stealth film provided by the utility model is designed based on the impedance matching principle of multi-layer wave absorbing materials. The VO2 material layer undergoes a metal-semiconductor phase transition at a critical temperature of 341K, and the optical properties of the film itself change, with the characteristic that the infrared emissivity decreases with increasing temperature, so that the emissivity of the film can be adaptively and reversibly adjusted according to the change of ambient temperature, and has a dual infrared band stealth function of 3-5μm and 8-14μm. At the same time, it has a higher emissivity in the non-infrared detection band of 5-8μm, and can realize the heat dissipation function of the stealth target in this band.

[0016] The thermochromic multi-band compatible infrared stealth film of the utility model has the characteristics of simple structure and convenient preparation method. The film can cover a large area of ​​the target surface. Compared with traditional infrared stealth films, it shows broader application prospects, is suitable for a variety of different application scenarios, and is conducive to large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the thermochromic multi-band compatible infrared stealth film of the utility model. DETAILED DESCRIPTION

[0018] The technical solution of the utility model is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the utility model without departing from the spirit and scope of the technical solution of the utility model shall be included in the protection scope of the utility model. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically noted, the raw materials used in the embodiments of the utility model can be obtained commercially; if not specifically noted, the technical means used in the embodiments of the utility model are all conventional means well known to those skilled in the art.

[0019] Example 1

[0020] This embodiment provides a thermochromic multi-band compatible infrared stealth film, referring to Figure 1 As shown, from top to bottom are the ZnS material layer, the VO2 material layer, the Si material layer and the Ag substrate layer, wherein the thickness of the ZnS material layer is 300nm, the thickness of the VO2 material layer is 200nm, the thickness of the Si material layer is 1000nm, and the thickness of the Ag substrate layer is 200nm.

[0021] The multilayer infrared stealth film provided in this embodiment is designed based on the impedance matching principle. The electrical conductivity of Ag is higher than that of other metals. Therefore, at the same thickness, the Ag substrate layer exhibits low sheet resistance. At the same time, the Ag substrate layer has a low emissivity and will be in thermal contact with a high-temperature target during actual application, and also serves as an infrared reflection functional layer.

[0022] The Si material layer has a higher refractive index and a lower absorption coefficient. As a dielectric layer, it can effectively perform impedance matching with the Ag substrate layer, thereby improving the performance of the multi-layer infrared stealth film.

[0023] The top layer material of the multi-layer infrared stealth film of this embodiment is a ZnS material layer. ZnS material has good transmission performance in the infrared spectrum range, can effectively transmit infrared light, and has good corrosion resistance under certain conditions, and can maintain good stability in some harsh environments.

[0024] The VO2 material layer is the intelligent core layer for the spectral radiation regulation of the film. At the critical temperature of 341K, the VO2 material will undergo a metal-semiconductor phase transition, and has the characteristic that the infrared emissivity decreases with increasing temperature, causing the optical properties of the film itself to change, and a reversible change from transmission to reflection of infrared light occurs. Therefore, the multi-layer infrared stealth film of this embodiment can achieve the effect of dynamically changing its own emissivity according to the change in the surface temperature of the object.

[0025] At the critical temperature of 341K, VO2 changes from a semiconductor state to a metallic state, resulting in an increase in reflectivity and a decrease in emissivity in the near-infrared band, which can achieve the stealth function of the target in the infrared band. From a microscopic perspective, the changes in the VO2 crystal and band structure lead to changes in the material's own properties: when VO2 is below the phase transition temperature, the crystal structure is a monoclinic tetragonal phase, which is transparent to infrared radiation; above the phase transition temperature, VO2 is converted into a metallic tetragonal phase, which has a strong reflective effect on the infrared band.

[0026] When the temperature is lower than 341K, since the ZnS material layer, the VO2 material layer, and the Si material layer are all transparent in the mid-infrared region and the bottom layer of the film is the Ag substrate layer, the multilayer film exhibits a high reflective effect in the mid-infrared region.

[0027] When the temperature is higher than 341K, VO2 changes from a semiconductor phase to a metal, and the Fabry-Perot cavity effect between the ZnS material layer and the metal makes the film produce an absorption enhancement effect in the mid-infrared region. However, based on the target infrared band stealth requirements, in order to reduce or lower the Fabry-Perot resonance effect, it is necessary to set an anti-reflection layer on the top of the film layer, so the ZnS material layer is selected as the anti-reflection layer and placed on the top of the film, which also plays a role in protecting the inner layer material and effectively prolonging the overall life of the film layer.

[0028] The thermochromic intelligent dual-band infrared stealth film of this embodiment is prepared by magnetron sputtering, and the specific steps are as follows:

[0029] Step 1: Deposition is performed on a clean stainless steel substrate in sequence using magnetron sputtering technology, with 99.99% pure argon as the sputtering gas, and maintained at room temperature. To ensure the uniformity of sputtering, the sputtering process is carried out on a rotating sample stage with a rotation speed of 5 rpm. Before the formal start, a 3-minute pre-sputtering is performed to effectively remove impurities on the target surface;

[0030] Step 2: For the Ag substrate layer, a 99.9% pure Ag metal target was used for sputtering in an argon atmosphere using a DC power supply. The sample was placed in a chamber and vacuum was drawn. When the initial chamber pressure reached 8×10 -4 After the pressure reaches 0.5 Pa, argon gas with a flow rate of 50 sccm is introduced and the pressure is controlled to be 0.5 Pa. After the pressure stabilizes, sputtering is started, the sputtering power of the DC power supply is 20-100 W, and the sputtering time is 20 minutes.

[0031] Step 3: For the Si material layer, VO2 material layer and ZnS material layer, Si target with a purity of 99.9%, VO2 target with a purity of 99.9% and ZnS target with a purity of 99.9% were respectively prepared by sputtering in an argon atmosphere using a radio frequency power supply. The sample with the completed Ag substrate layer was placed in the chamber and vacuum was drawn. When the initial pressure of the chamber reached 8×10 -4 After Pa, argon gas is introduced at a flow rate of 50 sccm and the pressure is controlled at 0.5 Pa. Sputtering begins after the pressure stabilizes. The sputtering power of the RF power supply is 200 W. The sputtering time of the Si material layer is 50 min, the sputtering time of the VO2 material layer is 20 min, and the sputtering time of the ZnS material layer is 30 min.

[0032] The selection of specific parameters such as sputtering power and time fully considers the thin film performance requirements and the optimization of the preparation process to ensure the quality and uniformity of the resulting film.

[0033] Example 2

[0034] The present embodiment provides a thermochromic multi-band compatible infrared stealth film, which comprises, from top to bottom, a ZnS material layer 1, a VO2 material layer 2, a Si material layer 3 and an Ag substrate layer 4, wherein the thickness of the ZnS material layer 1 is 400nm, the thickness of the VO2 material layer 2 is 200nm, the thickness of the Si material layer 3 is 1000nm, and the thickness of the Ag substrate layer 4 is 200nm.

[0035] Example 3

[0036] The present embodiment provides a thermochromic multi-band compatible infrared stealth film, which comprises, from top to bottom, a ZnS material layer 1, a VO2 material layer 2, a Si material layer 3 and an Ag substrate layer 4, wherein the thickness of the ZnS material layer 1 is 500nm, the thickness of the VO2 material layer 2 is 200nm, the thickness of the Si material layer 3 is 1000nm, and the thickness of the Ag substrate layer 4 is 200nm.

[0037] Example 4

[0038] The present embodiment provides a thermochromic multi-band compatible infrared stealth film, which comprises, from top to bottom, a ZnS material layer 1, a VO2 material layer 2, a Si material layer 3 and an Ag substrate layer 4, wherein the thickness of the ZnS material layer 1 is 600nm, the thickness of the VO2 material layer 2 is 200nm, the thickness of the Si material layer 3 is 1000nm, and the thickness of the Ag substrate layer 4 is 200nm.

[0039] Example 5

[0040] The present embodiment provides a thermochromic multi-band compatible infrared stealth film, which comprises, from top to bottom, a ZnS material layer 1, a VO2 material layer 2, a Si material layer 3 and an Ag substrate layer 4, wherein the thickness of the ZnS material layer 1 is 300nm, the thickness of the VO2 material layer 2 is 100nm, the thickness of the Si material layer 3 is 1000nm, and the thickness of the Ag substrate layer 4 is 200nm.

[0041] Example 6

[0042] The present embodiment provides a thermochromic multi-band compatible infrared stealth film, which comprises, from top to bottom, a ZnS material layer 1, a VO2 material layer 2, a Si material layer 3 and an Ag substrate layer 4, wherein the thickness of the ZnS material layer 1 is 300nm, the thickness of the VO2 material layer 2 is 150nm, the thickness of the Si material layer 3 is 1000nm, and the thickness of the Ag substrate layer 4 is 200nm.

[0043] Example 7

[0044] The present embodiment provides a thermochromic multi-band compatible infrared stealth film, which comprises, from top to bottom, a ZnS material layer 1, a VO2 material layer 2, a Si material layer 3 and an Ag substrate layer 4, wherein the thickness of the ZnS material layer 1 is 300nm, the thickness of the VO2 material layer 2 is 200nm, the thickness of the Si material layer 3 is 1000nm, and the thickness of the Ag substrate layer 4 is 200nm.

[0045] Example 8

[0046] The present embodiment provides a thermochromic multi-band compatible infrared stealth film, which comprises, from top to bottom, a ZnS material layer 1, a VO2 material layer 2, a Si material layer 3 and an Ag substrate layer 4, wherein the thickness of the ZnS material layer 1 is 300nm, the thickness of the VO2 material layer 2 is 250nm, the thickness of the Si material layer 3 is 1000nm, and the thickness of the Ag substrate layer 4 is 200nm.

[0047] Table 1 shows the influence of different thicknesses of ZnS material layers prepared in Examples 1 to 4 on the average emissivity of each band at 300K and 373K on the infrared stealth films.

[0048] Table 1

[0049]

[0050] The results in Table 1 show that for the infrared detection band of 3-5μm, adding a 400nm thick ZnS material layer will make the film have a greater emissivity change in both cold and hot states, while adding a 600nm thick ZnS material layer will make the film have a lower emissivity and a better infrared stealth effect; for the non-infrared detection band of 5-8μm, adding a 600nm thick ZnS material layer will make the film have a higher emissivity value and emissivity changes in different thermal environments, which is beneficial to the heat dissipation of high-temperature targets in this band; for another infrared detection band of 8-14μm, the overall average emissivity of the film is low, and the influence of cold and hot environment changes on the average emissivity of the film is not significant. Therefore, considering the overall average emissivity changes of the three-band film layer, when designing an infrared stealth film, a 600nm thick ZnS material layer can be selected as the top of the film to maximize the overall performance of the film in each band.

[0051] Infrared stealth film not only needs to have a low emissivity in the detection band, but also in the non-detection band, the film should preferably have high emissivity to achieve good heat dissipation. At this time, the 600nm thick ZnS material layer can fully meet the above requirements. When meeting the infrared stealth requirements of a single-band target: in the 8-14μm band, the 300nm thick ZnS material makes the overall performance of the film better; and for the 3-5μm band, the 600nm thick ZnS material film shows better stealth performance as a whole; considering all bands, the 600nm thick ZnS material film can be used as the first choice to meet the dual-band stealth requirements.

Claims

1. A thermochromic intelligent dual-band infrared stealth film, characterized in that: From top to bottom, they are a ZnS material layer (1), a VO2 material layer (2), a Si material layer (3) and an Ag substrate layer (4).

2. The thermochromic intelligent dual-band infrared stealth film according to claim 1, characterized in that: The thickness of the ZnS material layer (1) is 300-600 nm.

3. The thermochromic intelligent dual-band infrared stealth film according to claim 1, characterized in that: The thickness of the ZnS material layer (1) is 600 nm.

4. The thermochromic intelligent dual-band infrared stealth film according to claim 1, characterized in that: The thickness of the VO2 material layer (2) is 100-250 nm.

5. The thermochromic intelligent dual-band infrared stealth film according to claim 1, characterized in that: The thickness of the VO2 material layer (2) is 200 nm.

6. The thermochromic intelligent dual-band infrared stealth film according to claim 1, characterized in that: The thickness of the Si material layer (3) is not less than 1000 nm.

7. The thermochromic intelligent dual-band infrared stealth film according to claim 1, characterized in that: The thickness of the Ag substrate layer (4) is not less than 200 nm.

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