Broadband infrared radiation directional controller and design method thereof

Abstract

The present application relates to the field of radiation heat transfer, in particular to a broadband infrared radiation directional controller and a design method thereof. The controller provided by the present application is based on geometric optics, and the upper layer and the lower layer are respectively set to a specific structure by using two kinds of materials with high and low emissivity, so that the high (low) emissivity is only shown in the view area around the face normal (vertical line), and the low (high) emissivity is shown outside the view area, thereby realizing the directional control of infrared radiation. The reason for designing the two structures with the upper layer and the lower layer of two kinds of materials with high and low emissivity is to cope with different application environments, because the whole controller includes multiple grooves that meet the infrared isolation with each other. Finally, the present application realizes one-dimensional broadband infrared radiation directional control in the X-axis direction in the range where the structural parameters a and H are both greater than 10 times the characteristic wavelength, and can be applied to the fields of infrared camouflage, solar heating, radiation refrigeration and waste heat recovery, etc.

Description

Technical Field

[0001] This invention relates to the field of radiative heat transfer, specifically to a broadband infrared radiation directional controller and its design method, which can be applied to thermal camouflage, solar heating, radiative cooling, and waste heat recovery. Background Technology

[0002] As electronic devices evolve towards miniaturization, integration, and intelligence, thermal management becomes indispensable. Thus, "infrared radiation directional control," designed to address these issues, has emerged.

[0003] Thermal radiation is a phenomenon in which an object with a temperature above absolute zero radiates electromagnetic waves. Electromagnetic radiation with wavelengths between 0.75 and 1000 μm is called infrared radiation. It typically possesses characteristics such as non-directionality, incoherence, non-polarization, and a broad spectrum, making directional control of infrared radiation a formidable challenge. With scientific advancements, the mainstream methods for achieving directional control of infrared radiation currently include two approaches: one is the formation of subwavelength metasurface structures, and the other is multilayer film structures based on ENZ (near-zero gradient materials). The corresponding disadvantages are that subwavelength metasurfaces can only achieve narrowband directional control, while multilayer films of ENZ suffer from complex fabrication processes and can only achieve p-polarization directional control. Summary of the Invention

[0004] To address the aforementioned problems and shortcomings, and to resolve the issues existing in current infrared radiation directional control methods, this invention provides a broadband infrared radiation directional controller and its design method. Based on the principle of geometric optics propagation, a grating-like microstructure is designed, and infrared radiation directional control is achieved through material selection and size design.

[0005] A broadband infrared radiation directional controller consists of a control layer and a protection layer.

[0006] The control layer is a two-layer structure composed of high and low emissivity materials. The high / low emissivity material is selected as the lower base layer, while the upper low / high emissivity material is loaded onto the base layer in a completely overlapping manner. The portions loaded with the low / high emissivity material are outwardly protruding pillars (e.g., Figure 2 The control layer consists of n cuboids, with each externally protruding pillar having its two ends aligned and distributed at equal intervals on the base layer. This results in a continuous groove structure where the externally protruding pillars serve as the groove walls and high / low emissivity materials serve as the groove bottoms.

[0007] The difference in emissivity between high-emissivity and low-emissivity materials is ≥0.4; infrared isolation is satisfied between adjacent grooves (e.g., Figure 3 As shown in the figure, the transmittance of the convex pillar to infrared light is less than 10%; with the arrangement direction of the grooves as the X-axis direction and the column length direction of the convex pillar as the Y-axis direction, the density of the grooves in the control layer in the X-axis direction is 2-66 per cm.

[0008] Where a is the width of the groove bottom of a single groove not covered by the protruding pillar, and d n H is the width of a single protruding pillar within the base layer coverage area, H is the trench wall height, h is the base layer thickness, t is the protective layer thickness, and ε is the... 底 ε is the emissivity of the bottom material of the tank. 侧 Emissivity of the tank wall material; Δε>ε 小 Δε represents the theoretical emissivity change, ε 小 The minimum theoretical emissivity variation set for the application target. d n ≤a, 0.15mm≤a≤5mm, 0.1mm≤H≤5mm, 0 <d n ≤0.5mm, 0.05mm≤h≤3mm, 0.1mm≤t≤3mm; the entire controller is applicable to the characteristic wavelength range of parameters a and H, which is because, according to the principle of optical propagation, theoretically, the controller can achieve directional control only if both a and H are greater than 10 times the characteristic wavelength.

[0009]

[0010] The angle between the two tangents from the bottom of one convex pillar to another adjacent convex pillar within the same groove is the cutoff angle θ. When the observation angle is less than the cutoff angle θ, high / low emissivity material at the bottom of the groove can be seen, while when the observation angle is greater than the cutoff angle θ, only low / high emissivity material on the groove wall can be seen; θ < θ 大 θ 大 The maximum theoretical cutoff angle set for the application objective. For example... Figure 2 As shown, when looking down at the control layer, the viewing area along the X-axis of the control layer is determined by a cutoff angle θ (e.g., Figure 4 As shown in the figure, there is no corresponding cutoff angle in the Y-axis direction (the direction of the column length of the convex column). Therefore, when the observation angle is less than the cutoff angle θ, the high / low emissivity material at the bottom of the tank is visible; while when the observation angle is greater than the cutoff angle θ, only the low / high emissivity material on the tank wall is visible.

[0011]

[0012] The protective layer is disposed under the substrate layer to protect the control layer and prevent it from being torn during transfer or preparation.

[0013] Furthermore, the infrared light transmittance of the protruding post is less than 5%; more preferably, the infrared light transmittance of the protruding post is less than 1%. Better infrared isolation between adjacent grooves results in better blocking of lateral radiation from the groove bottom by the groove wall, such as... Figure 3 As shown.

[0014] Furthermore, the protective layer is made of polyimide or polyethylene terephthalate.

[0015] Furthermore, the high emissivity material is selected from materials with an emissivity ≥ 0.7 (preferably polymer materials if considering the requirements of flexible devices) to improve device performance. The low emissivity material is selected from materials with an emissivity ≤ 0.3.

[0016] Furthermore, the cross-sectional shape of the groove is symmetrical from left to right. This is because when the cutoff angle θ is not symmetrical from left to right (such as when the groove is wedge-shaped), heat will not be transferred in the forward direction in the field of radiative heat transfer, thus affecting thermal efficiency. Its application in the field of infrared camouflage can effectively achieve bidirectional infrared camouflage.

[0017] Furthermore, when applied in the field of radiative heat transfer, 0° < θ ≤ 140° is used to improve device performance.

[0018] Furthermore, the protruding pillar is constructed by an integral extension of a lower base layer material, with an upper layer material covering the surface. Specifically, the base layer material on the same plane extends upwards and outwards within the area covered by the upper layer material, serving as the internal mechanical support component for the upper protruding pillar, thus improving the overall mechanical performance of the controller. Examples of suitable infrared high-transmittance materials include: 3-5µm infrared high-transmittance materials: silicon, germanium, zinc selenide, calcium fluoride, barium fluoride, polyvinyl chloride, polyethylene, polydimethylsiloxane, polymethyl methacrylate, polystyrene, polyethylene terephthalate, polycarbonate, and polyetherimide; 8-14µm infrared high-transmittance materials include: germanium, zinc selenide, barium fluoride, polyvinyl chloride, polyethylene, polystyrene, and polyethylene terephthalate.

[0019] Furthermore, the cutoff angle θ is reduced by 10% to compensate for the problem of the actual value being too large due to the processing technology.

[0020] Furthermore, a layer of infrared-transparent medium with characteristic wavelength band is also prepared on the exposed area of ​​the control layer of the controller to protect the controller and improve its durability.

[0021] The design method of the above-mentioned broadband infrared radiation directional controller includes the following steps:

[0022] Step 1: Based on the application scenario and target object, first determine ε 底 ε 侧 The types of protective layer materials and their corresponding thicknesses h and t, where 0.05mm≤h≤3mm and 0.1mm≤t≤3mm.

[0023] Step 2: Determine d based on the type and properties of the materials selected in Step 1. n 0 <d n ≤0.5mm, and the corresponding processing method; when d n For diameters >0.1mm, a CNC engraving machine is the preferred processing method; for diameters <0.001mm, a CNC engraving machine is preferred. nFor diameters ≤0.1mm, photolithography is preferred; for diameters 0 < d, photolithography is preferred. n Electron beam exposure technology is preferred for apertures ≤0.001mm.

[0024] Step 3: Determine H and a based on the application scenario and the target object's need for thinness and lightness, where 0.15mm ≤ a ≤ 5mm and 0.1mm ≤ H ≤ 5mm; simultaneously satisfying Δε > ε 小 and θ<θ 大 ;

[0025] First, fix H to determine the final value of a; or draw a curve relationship between a and H, and choose the optimal value according to the application scenario.

[0026] In summary, the controller provided by this invention employs two materials with high and low emissivity in its upper and lower layers, respectively, to create a specific structure. This ensures that high (low) emissivity is only observed within the viewing area around the center of the surface normal (perpendicular line), while low (high) emissivity is observed outside the viewing area, thereby achieving directional infrared radiation control. The reason for designing two structures with interchangeable high and low emissivity materials in the upper and lower layers is to address different application environments. This is because the entire controller includes multiple grooves, and each groove satisfies infrared isolation from adjacent grooves, with the groove walls effectively blocking lateral radiation from the bottom surface of the grooves. Ultimately, this invention achieves one-dimensional broadband infrared radiation directional control in the X-axis direction within a range where both structural parameters a and H are greater than 10 times the characteristic wavelength, and can be applied to infrared camouflage, solar heating, radiative cooling, and waste heat recovery, among other radiative heat transfer fields. Attached Figure Description

[0027] Figure 1 This is a design flowchart of the present invention;

[0028] Figure 2 An exploded perspective view of the control layer of the controller in this embodiment;

[0029] Figure 3 This is a schematic diagram of the recessed infrared isolation of the controller in the embodiment;

[0030] Figure 4 This is a cross-sectional view of the groove in the controller layer of the embodiment;

[0031] Figure 5 This is a schematic diagram of the cutoff angle when the groove cross-section of the controller control layer is trapezoidal, as shown in the example.

[0032] Figure 6 This is a schematic diagram illustrating the application of the controller in the field of radiative heat transfer.

[0033] Figure 7 This is a cross-sectional view of the controller in the embodiment;

[0034] Figure 8 Infrared thermograms of the sample from different angles for the example;

[0035] Figure 9 Infrared thermograms of the sample from different angles for the example;

[0036] Figure 10 The curve relationship between a and H is shown in the example controller design. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0038] A design method for a broadband infrared radiation directional controller (e.g.) Figure 1 (As shown), including the following steps:

[0039] Step 1: Based on the application scenario and target object, first determine ε 底 ε 侧 The types of protective layer materials and their corresponding thicknesses h and t, where 0.05mm≤h≤3mm and 0.1≤t≤3mm.

[0040] In this embodiment, in order to obtain a high theoretical emissivity change Δε, the difference in emissivity between the high emissivity material and the low emissivity material is selected to be ≥0.7, preferably the emissivity of the high emissivity material is ≥0.9, and the low emissivity material is selected to be a material with an emissivity ≤0.1.

[0041] Because polymers are flexible and typically have an emissivity >0.9, high-emissivity materials are usually chosen from polymers such as polydimethylsiloxane, polymethyl methacrylate, and polyimide. Low-emissivity materials are usually chosen from common metals such as aluminum and silver.

[0042] High emissivity material selection: polydimethylsiloxane, polymethyl methacrylate, polyimide; polycarbonate, polyethylene terephthalate, polyethylene naphthalate, high-density polyethylene, low-density polyethylene, linear low-density polyethylene; polyethylene, polypropylene, polystyrene, polyvinyl chloride, nylon, polycarbonate, polyurethane, polytetrafluoroethylene, polyethylene terephthalate, paint, cement, basalt, butyl rubber, cis-butadiene rubber, chloroprene rubber, ethylene propylene diene monomer (EPDM) rubber, acrylate rubber, polyurethane rubber, silicone rubber, fluororubber, polyisoprene, nylon, polyester, acrylic polyester fibers, aramid, polypropylene fibers; acrylic resins derived from epoxy resins, polyesters, polyethers, and polyurethanes; polyurethanes (polyurea) derived from isocyanates and polyols (or polyamines); isocyanate derivatives having at least one acrylic side group; epoxy resins other than acrylic-modified epoxy resins; and mixtures and combinations thereof. Polydimethylsiloxane, polymethyl methacrylate, and polyimide are particularly preferred.

[0043] Low emissivity material options: aluminum, silver, platinum, gold, tin, copper, tantalum, titanium, iron, tungsten, nickel, chromium, steel, or stainless steel.

[0044] Protective layer material selection: plastic rolls, rubber, asphalt coatings; high-density polyethylene, low-density polyethylene, polyvinyl chloride, chlorinated polyethylene, chlorosulfonated polyethylene, polyolefins, ethylene-propylene rubber, chloroprene rubber, butene rubber, thermoplastic synthetic rubber, alcohol rubber, polyimide or polyethylene terephthalate.

[0045] Step 2: Determine d based on the type and properties of the materials selected in Step 1. n 0 <d n ≤0.5mm, and the corresponding processing method; considering the precision issues of the processing technology, when d n When the diameter is >0.1mm, the processing method is CNC engraving machine; when the diameter is <0.001mm, the processing method is CNC engraving machine. n For diameters ≤0.1mm, photolithography is preferred; for diameters 0 < d, photolithography is preferred. n Electron beam exposure technology is preferred for apertures ≤0.001mm.

[0046] Step 3: Determine H and a based on the application scenario and the target object's need for thinness and lightness, where 0.15mm ≤ a ≤ 5mm and 0.1mm ≤ H ≤ 5mm; simultaneously satisfying Δε > ε 小 and θ<θ 大 θ 大 The maximum theoretical cutoff angle set for the application target, ε 小 The minimum theoretical emissivity variation set for the application target.

[0047] First, fix H to determine the final value of a; or draw a curve relationship between a and H, and choose the optimal value according to the application scenario.

[0048] The theoretical range of the cutoff angle θ is 0°-180° (0° corresponds to a continuous arrangement of convex pillars, with the control layer becoming a two-layer planar membrane structure; 180° corresponds to no convex pillars, with the control layer becoming a single-layer planar membrane structure). The theoretical range of the emissivity variation Δε is between 0 and 1 (when ε...). 底 =ε 侧 When Δε is zero, it can take the value 0; when the bottom material of the groove is a blackbody, ε 底 =1,ε 侧 Select metal ε 侧 →0, a is much greater than d n At that time, Δε approaches 1 infinitely.

[0049] a / d nThis represents the ratio of the bottom width of the tank to the width of the protruding pillar. From a top view, it represents the ratio of the area of ​​the high-emissivity material (base layer) to the area of ​​the low-emissivity material (upper tank wall layer). It is used to measure the variation of the controller's maximum and theoretical emissivity. The variation of maximum and theoretical emissivity increases with a / d. n As a / H increases, the angle θ increases. a / H represents the tangent of half the theoretical cutoff angle θ / 2, and the cutoff angle θ increases as a / H increases.

[0050] In the field of radiative heat transfer, a larger theoretical emissivity change is desirable to improve thermal efficiency. The minimum emissivity change ε ​​is defined as the theoretical emissivity change that just meets the thermal efficiency requirement. 小 (like Figure 6 (As shown). At this time, the cutoff angle is 0° < θ ≤ 140°. This is because the material naturally has directional control when the cutoff angle is > 140°, while the cutoff angle ≤ 140° can reflect the role of the controller in improving thermal efficiency by concentrating heat (for example, when it is greater than 140°, the emissivity of a flat metal increases with the increase of the angle, while the emissivity of an insulating medium decreases with the increase of the angle).

[0051] In different fields and among different users, the requirements for the above two parameters vary. By analyzing a and d... n By designing the dimensions of H appropriately, dynamic control can be achieved over the cutoff angle θ and the change in theoretical emissivity Δε.

[0052] Figure 2 The sample structure of the broadband infrared radiation directional controller prepared in this embodiment is shown, wherein the protruding pillar is a split rectangular pillar (if a base layer epitaxial shaping is used, wrapping the epitaxial portion with an upper layer material will result in better mechanical properties). 200 - high emissivity layer, 210 - groove, 211 - groove wall, 212 - bottom of the groove (upper surface of high emissivity layer 200), 213 - low emissivity protruding pillar, 214 - lower surface of high emissivity layer 200. The viewing plane 215 is shown positioned relative to the YZ plane (defined by a perpendicular line 216 parallel to the Z-axis and a line 217 parallel to the Y-axis) at this azimuth angle. The viewing plane 215 includes a perpendicular line 216 parallel to the Z-axis and extends perpendicular to the XY plane. Figure 7 This is a cross-sectional view of the sample in this embodiment, 300 - protective layer, 218 - bottom surface of the protective layer.

[0053] Figure 3 The infrared isolation diagram of the sample is shown in the example. The infrared radiation at the bottom of groove No. 2 is reflected to the outside by the groove wall, while only less than 10% (preferably less than 5% or 1% infrared light transmittance) of the infrared light is transmitted laterally into groove No. 1.

[0054] Figure 4This is a cross-sectional view of the groove. For any angle greater than the cutoff angle θ, the emissivity exhibited by the controller is the same as the groove wall emissivity. The magnitude of the cutoff angle θ varies depending on the azimuth angle and the geometry of the groove 210. In some embodiments, the cutoff angle can vary from 20° to approximately 80°. In this invention, the azimuth angle can only be perpendicular to the grating ( Figure 2 In the XZ plane, the maximum cutoff angle is obtained and the cutoff angle changes with the azimuth angle.

[0055] Furthermore, the actual cutoff angle θ tested is usually slightly larger than the theoretical cutoff angle θ. This is because the groove cross-section, due to manufacturing processes, typically exhibits a frustum shape; the groove cross-section is a trapezoid with a wider top and narrower bottom (e.g., Figure 5 As shown on the left, it can be seen that θ 梯1 >θ 立 The groove cross-section is a trapezoid, narrower at the top and wider at the bottom (e.g., Figure 5 As shown on the right, it can be seen that θ 梯2 >θ 立 Considering that the measured viewing angle increases due to the direct emission after two reflections at the bottom of the groove, the theoretical value of the cutoff angle θ is reduced by 10% to compensate for the negative impact of external factors.

[0056] Figure 6 This is a schematic diagram illustrating the application of an infrared radiation directional controller in the field of radiative heat transfer. The tank wall concentrates the energy radiated from the bottom of the tank directly above, improving the heat conversion efficiency of the absorber. The theoretical emissivity change that just meets the heat conversion efficiency requirement is set as the minimum emissivity change ε. 小 .

[0057] In this embodiment, the application scenario and target object limit the theoretical emissivity variation ε 小 =0.5, theoretical cutoff angle θ 大 =60°. The measured cutoff angle θ was determined using an infrared thermal imager, and the measured emissivity was calculated using the Stephen-Boltzmann formula: E = σT 4 The infrared thermal imager converts the displayed temperature into the corresponding emissivity.

[0058] Because the infrared band spans a very large range, the band tested in this embodiment is between 7.5um and 14um, but this does not mean that the present invention can only achieve directional control in the 7.5um-14um band.

[0059] Example 1

[0060] The high emissivity material is polydimethylsiloxane (ε = 0.96), and the low emissivity material is vacuum-deposited aluminum (ε = 0.1). The substrate or protective layer has no impact on the functionality of the target; only flexibility and thinness are considered. Polyimide is selected as the protective layer material.

[0061] Using a 0.3mm wire from a CNC engraving machine, determine d. n Both are 0.3mm; based on the material selection and the requirement for thinness, H = 1.5mm and h = 0.5mm were determined, and the thickness of the entire sample was 2mm.

[0062] In order to make Δε>ε 小 , a needs to be greater than the critical value a min To make θ < θ 大 a needs to be less than a max .

[0063] According to the formula:

[0064]

[0065] The calculated range for 'a' is 0.42 mm ≤ a ≤ 0.86 mm.

[0066] The list is as follows:

[0067]

[0068] The final design has a = 0.6 mm and d = 0.6 mm. n =0.3mm, h=1.5mm, θ=43.6°, Δε=0.57.

[0069] Figure 8-9 For the infrared thermal image of the above dimensions, from Figure 9 (from left to right) Figure 10 As can be seen from the top to the bottom, the color becomes darker as the viewing angle increases, indicating a lower emissivity.

[0070] Example 2

[0071] The high-emissivity material is polydimethylsiloxane (ε = 0.96), and the low-emissivity material is vacuum-deposited aluminum (ε = 0.1). The substrate or protective layer has no impact on the target's functionality; only flexibility and thinness are considered. Polyimide is chosen as the protective layer material. In this embodiment, the protruding pillar is constructed by an integral epitaxial layer of the lower substrate material, covered by an upper material, with an aluminum film thickness of 200 nm.

[0072] Using a 0.3mm wire from a CNC engraving machine, fix d n =0.3mm; based on material selection and requirements for thinness and lightness, h=0.5mm.

[0073]

[0074] Find the boundary value solution for the given conditions Δε > 0.5 and θ < 60°, and plot the graph. Figure 10 The gray area shown represents the values ​​of a and H that satisfy the given conditions.

[0075] As can be seen from the above embodiments, the broadband infrared radiation directional controller provided by this invention, based on geometric optics, uses two materials with high and low emissivity respectively in a specific structure for the upper and lower layers. This results in high (low) emissivity only within the viewing area around the center located on the surface normal (perpendicular line), and low (high) emissivity outside the viewing area. The reason for designing two structures with interchangeable high and low emissivity materials in the upper and lower layers is to cope with different application environments, because the entire controller includes multiple grooves that satisfy infrared isolation between each other. Ultimately, this invention achieves one-dimensional broadband infrared radiation directional control in the X-axis direction and can be applied to infrared camouflage, solar heating, radiative cooling, and waste heat recovery, among other radiative heat transfer fields.

Claims

1. A broadband infrared radiation directional controller, characterized in that: It consists of a control layer and a protection layer; The control layer is a two-layer structure composed of high and low emissivity materials, which are fully distributed in the target area. The high / low emissivity material is selected as the lower base layer, and the low / high emissivity material of the upper layer is loaded on the base layer in a partitioned manner to completely cover it. The part loaded with low / high emissivity material consists of n protruding pillars. The two ends of each protruding pillar are aligned and distributed in parallel at equal intervals on the base layer, so that the control layer forms a continuous groove structure with the protruding pillars as the groove walls and the high / low emissivity material as the groove bottom. The difference in emissivity between high-emissivity and low-emissivity materials is ≥0.4; adjacent grooves are infrared isolated, i.e., the transmittance of the convex pillars to infrared light is less than 10%; with the arrangement direction of the grooves as the X-axis direction and the length direction of the convex pillars as the Y-axis direction, the density of the grooves in the control layer in the X-axis direction is 2-66 / cm. Where a is the width of the groove bottom of a single groove not covered by the protruding pillar, and d n H is the width of each protruding pillar within the base layer coverage area, H is the trench wall height, h is the base layer thickness, t is the protective layer thickness, and ε is the width of each protruding pillar within the base layer coverage area. 底 ε is the emissivity of the bottom material of the tank. 侧 Emissivity of the tank wall material; Δε>ε 小 Δε represents the theoretical emissivity change, ε 小 The minimum theoretical emissivity variation set for the application target; d n ≤a, 0.15mm≤a≤5mm, 0.1mm≤H≤5mm, 0 <d n ≤0.5mm, 0.05mm≤h≤3mm, 0.1mm≤t≤3mm; and parameters a and H > 10 times the characteristic wavelength; ； The angle between the two tangents from the bottom of one convex pillar to another adjacent convex pillar within the same groove is the cutoff angle θ. When the observation angle is less than the cutoff angle θ, high / low emissivity material at the bottom of the groove can be seen, while when the observation angle is greater than the cutoff angle θ, only low / high emissivity material on the groove wall can be seen; θ < θ 大 θ 大 The maximum theoretical cutoff angle set for the application target; ； The protective layer is disposed under the substrate layer to protect the control layer and prevent it from being torn during transfer or preparation.

2. The broadband infrared radiation directional controller as described in claim 1, characterized in that: The protective layer is made of polyimide or polyethylene terephthalate.

3. The broadband infrared radiation directional controller as described in claim 1, characterized in that: The high emissivity material is selected from materials with an emissivity ≥ 0.

7.

4. The broadband infrared radiation directional controller as described in claim 1, characterized in that: The low emissivity material is selected from materials with an emissivity ≤ 0.

3.

5. The broadband infrared radiation directional controller as described in claim 1, characterized in that: The cross-sectional shape of the groove is symmetrical from left to right.

6. The broadband infrared radiation directional controller as described in claim 1, characterized in that: The protruding pillar is formed by an integral extension of the lower base layer material and an upper layer material covering the surface, so as to improve the mechanical performance of the entire controller.

7. The broadband infrared radiation directional controller as described in claim 1, characterized in that: When applied to the field of radiative heat transfer, 0° < θ ≤ 140°; when applied to the infrared camouflage of aircraft, θ ≤ 90°.

8. The broadband infrared radiation directional controller as described in claim 1, characterized in that: The exposed area on the upper surface of the controller's control layer is also coated with a layer of infrared-transparent medium in the characteristic band to protect the controller and improve its durability.

9. The broadband infrared radiation directional controller as described in claim 1, characterized in that: The cutoff angle θ is set to be 10% smaller to compensate for the problem of the actual value being too large due to the processing technology.

10. The design method of the broadband infrared radiation directional controller as described in claim 1, characterized in that, Includes the following steps: Step 1: Based on the application scenario and target object, first determine ε 底 ε 侧 The type of protective layer material and the corresponding thickness h and t, 0.05mm≤h≤3mm, 0.1mm≤t≤3mm; Step 2: Determine d based on the type and properties of the materials selected in Step 1. n 0 <d n ≤0.5mm, and the corresponding processing method; when d n When the diameter is >0.1mm, the processing method is CNC engraving machine; when the diameter is <0.001mm, the processing method is CNC engraving machine. n When the diameter is ≤0.1mm, it is a photolithography technique; 0<d n ≤0.001mm is for electron beam lithography. Step 3: Determine H and a based on the application scenario and the target object's need for thinness and lightness, where 0.15mm ≤ a ≤ 5mm and 0.1mm ≤ H ≤ 5mm; simultaneously satisfying Δε > ε 小 and θ<θ 大 ; First, fix H to determine the final value of a; or draw a curve relationship between a and H, and choose the optimal value according to the application scenario.

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