Near-infrared high-reflection structural color optical filter and preparation method thereof

Abstract

The invention provides a near-infrared high-reflection structural color optical filter and a preparation method thereof, and relates to the technical field of optics, the near-infrared high-reflection structural color optical filter comprises a substrate, and a reflection layer, a first dielectric layer, a first absorption layer, a second dielectric layer, a second absorption layer and an anti-reflection layer which are sequentially formed on the substrate; the reflecting layer, the first dielectric layer and the first absorption layer form a first optical resonant cavity, and the first absorption layer, the second dielectric layer and the second absorption layer form a second optical resonant cavity; the absorptivity of the first absorption layer and the second absorption layer to visible light in a target color wavelength range is smaller than the absorptivity of the first absorption layer and the second absorption layer to visible light in a non-target color wavelength range, and the absorptivity of the first absorption layer and the second absorption layer to near-infrared light is smaller than a preset absorptivity threshold value. In this way, the two continuous asymmetric optical resonant cavities and the top anti-reflection layer are adopted, high-purity and high-brightness colors are achieved in the visible light range, the cooling function is achieved through the high reflectivity of the near-infrared band, cost is low, and the technology is simple.

Description

Technical Field

[0001] The invention relates to the field of optical technology, and in particular to a near-infrared high-reflection structural color filter and a preparation method thereof. Background Art

[0002] Structural color, also known as physical color or interference color, is a color produced by physical phenomena such as interference and diffraction of light on the micro-nanostructure inside or on the surface of an object. This color is not determined by pigments, but depends on the effect of the fine structure inside or on the surface of the material on the incident light. In recent years, structural color has attracted widespread attention as a powerful alternative to traditional pigments and dyes, and is suitable for many applications such as color display / printing, information encryption, colorimetric sensors and optical decoration.

[0003] The near-infrared region outside of visible light (i.e., the spectral region from 800 to 1600 nm) accounts for most of the heat generated by sunlight, so materials / systems with high near-infrared reflectivity can be widely used in roof coatings, smart windows, and vehicle coatings to alleviate the negative effects of thermal conduction effects. For aesthetic purposes, it is urgent to integrate high-performance structural color devices into near-infrared high-reflectivity materials / systems.

[0004] At present, the methods for integrating structural color devices into near-infrared high-reflection materials / systems mainly include:

[0005] 1. Applying an organic solvent mixed with nano-Al2O3 particles and ordinary glass particles to obtain a radiation cooling coating;

[0006] 2. Cooling coating made with 2D silicon dioxide grating structure on top of ZnO / Ag / ZnO;

[0007] 3. Cooling coatings made of ceramic materials such as alumina (Al2O3) and silicon dioxide (SiO2);

[0008] 4. A cooling coating prepared using a porous polyethylene (PE) film;

[0009] 5. Adding FP (Fabry-Pérot cavity) structure to the existing white / silver solar cooler to achieve colored cooling coating;

[0010] 6. Use a radiation cooling coating on the bottom layer and fluorescent powder on the top layer to obtain color and cooling effect.

[0011] However, the above methods have complicated processes, and most of them have a single color and are not aesthetically pleasing. In addition, organic materials have a large impact on the environment and are not environmentally friendly. Moreover, when PE materials are exposed to the natural environment for a long time, they may be affected by factors such as ultraviolet rays, temperature changes and humidity, resulting in a decrease in material performance, and thus poor device stability. Among them, the colored cooling coating using the FP cavity structure is aesthetically pleasing, but the structural color obtained by simply using layered films can only achieve absorption within a narrow wavelength range, thus greatly limiting the purity of the generated structural color. Summary of the invention

[0012] The purpose of the present invention is to provide a near-infrared high-reflection structural color filter and a preparation method thereof, so as to achieve high-purity and high-brightness colors in the visible light range, and utilize the high reflectivity of the near-infrared band to achieve a cooling function, with low cost and simple process.

[0013] In a first aspect, the present invention provides a near-infrared high-reflection structural color filter, comprising a substrate and a reflection layer, a first dielectric layer, a first absorption layer, a second dielectric layer, a second absorption layer and an anti-reflection layer sequentially formed on the substrate;

[0014] The reflective layer, the first dielectric layer and the first absorption layer constitute a first optical resonant cavity, and the first absorption layer, the second dielectric layer and the second absorption layer constitute a second optical resonant cavity; the first absorption layer and the second absorption layer both have a lower absorptivity to visible light within a target color wavelength range than absorptivity to visible light within a non-target color wavelength range, and absorptivity to near-infrared light than a preset absorptivity threshold.

[0015] Furthermore, the reflectivity of the reflective layer is greater than 90%.

[0016] Furthermore, the material of the reflective layer includes aluminum, copper, gold, platinum, palladium or silver.

[0017] Furthermore, the reflective layer is made of aluminum, and the thickness of the reflective layer is greater than 70 nm.

[0018] Furthermore, the material of the first dielectric layer, the material of the second dielectric layer and the material of the anti-reflection layer all include at least one of niobium titanium oxide, silicon dioxide, silicon oxynitride, aluminum oxide, titanium dioxide, niobium pentoxide, tantalum pentoxide, zirconium oxide, yttrium oxide, hafnium dioxide, silicon nitride, zinc selenide, tungsten oxide and zinc sulfide.

[0019] Furthermore, the reflectivity of the first absorption layer and the second absorption layer to visible light within the target color wavelength range is greater than the reflectivity to visible light within the non-target color wavelength range.

[0020] Furthermore, the material of the first absorption layer and the material of the second absorption layer both include germanium or silicon.

[0021] Furthermore, the reflective layer is made of aluminum, and the first absorption layer and the second absorption layer are both made of germanium.

[0022] Furthermore, the material of the first dielectric layer, the material of the second dielectric layer and the material of the anti-reflection layer are all silicon nitride.

[0023] In a second aspect, the present invention further provides a method for preparing the near-infrared high-reflection structural color filter as in the first aspect, comprising:

[0024] forming a reflective layer on a substrate;

[0025] forming a first dielectric layer on the reflective layer;

[0026] forming a first absorption layer on the first dielectric layer;

[0027] forming a second dielectric layer on the first absorbing layer;

[0028] forming a second absorption layer on the second dielectric layer;

[0029] An anti-reflection layer is formed on the second absorption layer.

[0030] In the near-infrared high-reflection structural color filter and the preparation method thereof provided by the present invention, the near-infrared high-reflection structural color filter includes a substrate and a reflective layer, a first dielectric layer, a first absorption layer, a second dielectric layer, a second absorption layer and an anti-reflection layer formed in sequence on the substrate; the reflective layer, the first dielectric layer and the first absorption layer constitute a first optical resonant cavity, and the first absorption layer, the second dielectric layer and the second absorption layer constitute a second optical resonant cavity; the first absorption layer and the second absorption layer both have an absorption rate for visible light within a target color wavelength range that is lower than an absorption rate for visible light within a non-target color wavelength range, and an absorption rate for near-infrared light that is lower than a preset absorption rate threshold. In this way, two continuous asymmetric optical resonant cavities and an anti-reflection layer on the top are used, and constructive interference phenomenon is generated for visible light within the required target color wavelength range in the two continuous asymmetric optical resonant cavities, and optical absorption is performed on visible light within the non-target color wavelength range. The absorption is enhanced by multi-cavity resonance, and the reflection of visible light within the non-target color wavelength range is fully suppressed. The first absorption layer and the second absorption layer have low absorption rates for near-infrared light, ensuring high reflectivity of near-infrared light. Therefore, the near-infrared high-reflection structural color filter achieves high-purity and high-brightness colors in the visible light range, and realizes the cooling function by utilizing the high reflectivity of the near-infrared band. At the same time, this multi-layer thin film structure is easy to prepare, low-cost, and simple in process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of the structure of a near-infrared high-reflection structural color filter provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structure of another near-infrared high-reflection structural color filter provided by an embodiment of the present invention;

[0034] Figure 3 A cross-sectional view of a near-infrared high-reflection structural color filter provided by an embodiment of the present invention;

[0035] Figure 4 A reflection spectrum corresponding to a blue near-infrared high-reflection structural color filter provided by an embodiment of the present invention;

[0036] Figure 5 A reflection spectrum corresponding to a green near-infrared high-reflection structural color filter provided by an embodiment of the present invention;

[0037] Figure 6 A reflection spectrum corresponding to a red near-infrared high-reflection structural color filter provided by an embodiment of the present invention;

[0038] Figure 7 Three color samples observed at four different angles provided by an embodiment of the present invention;

[0039] Figure 8 A schematic flow chart of a method for preparing a near-infrared high-reflection structural color filter provided in an embodiment of the present invention.

[0040] Icon: 101 - substrate; 102 - reflective layer; 103 - first dielectric layer; 104 - first absorption layer; 105 - second dielectric layer; 106 - second absorption layer; 107 - anti-reflective layer. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] By constructing a structure from a planar thin film to a dielectric or metal subwavelength nanostructure array, a unique color with a wide color gamut is achieved. Compared with the colors obtained by nanostructures that require complex and expensive photolithography processes, the structural colors produced by multilayer thin film stacks can be prepared by methods such as vacuum deposition or electrochemical deposition, which is low-cost and simple in process, and therefore more commercially valuable.

[0043] The structural colors obtained by layered thin films can only achieve absorption within a narrow wavelength range, which greatly limits the purity of the generated structural colors. In order to obtain high-purity reflected colors, some tentative solutions have also been proposed, such as using high-loss metals or adding FP resonant cavities to broaden the absorption bandwidth. However, the color purity of these devices is still limited by the influence of surrounding wavelengths; or using ultra-thin double-layer dielectrics as effective ideal absorbers and combining ultra-thin organic dye layers in the FP cavity structure to enhance the purity of the reflected color, but the color adjustment process is cumbersome, and the use of organic dyes will also reduce the cooling effect in the near-infrared band.

[0044] Based on this, a near-infrared high-reflection structural color filter and a preparation method thereof provided in an embodiment of the present invention can achieve high-purity and high-brightness colors in the visible light range and realize cooling function in the near-infrared region with low cost and simple process.

[0045] To facilitate understanding of this embodiment, a near-infrared high-reflection structural color filter disclosed in an embodiment of the present invention is first introduced in detail.

[0046] like Figure 1 As shown, a near-infrared high-reflection structural color filter provided by an embodiment of the present invention includes: a substrate 101 and a reflective layer 102, a first dielectric layer 103, a first absorption layer 104, a second dielectric layer 105, a second absorption layer 106 and an anti-reflection layer 107 formed in sequence on the substrate 101.

[0047] The reflective layer 102, the first dielectric layer 103 and the first absorption layer 104 constitute a first optical resonant cavity, and the first absorption layer 104, the second dielectric layer 105 and the second absorption layer 106 constitute a second optical resonant cavity. The first absorption layer 104 and the second absorption layer 106 both have a lower absorptivity to visible light in the target color wavelength range than absorptivity to visible light in the non-target color wavelength range, and absorptivity to near-infrared light than a preset absorptivity threshold.

[0048] Specifically, the substrate 101 is the basis of the near-infrared high-reflection structure color filter and is used to provide physical support. The reflective layer 102 on the substrate 101 is used to provide high reflectivity. The first dielectric layer 103 and the second dielectric layer 105 are used as spacer layers. The first absorption layer 104 and the second absorption layer 106 are used to absorb the wavelength part of the non-target color band, that is, to absorb visible light outside the target color wavelength range, to improve the purity of the color; at the same time, the absorption rate of near-infrared light is low to ensure high near-infrared light reflectivity. The anti-reflection layer 107 is located at the outermost layer of the near-infrared high-reflection structure color filter (that is, located at the top). The near-infrared high-reflection structure color filter achieves high-purity and high-brightness colors and cooling functions in the near-infrared region by combining the above layers in sequence, while maintaining good optical properties and environmental adaptability. Different colors can be achieved by changing the thickness of each film (including the first dielectric layer 103, the first absorption layer 104, the second dielectric layer 105, the second absorption layer 106 and the anti-reflection layer 107).

[0049] The above target color wavelength range is the visible light wavelength range corresponding to the color that the near-infrared high-reflection structural color filter needs to present. For example, the target color wavelength range corresponding to red is 600 to 750nm, the target color wavelength range corresponding to green is 495 to 570nm, and the target color wavelength range corresponding to blue is 450 to 495nm. It should be noted that the target color wavelength range here is only an example. In specific implementation, the target color wavelength range will be different depending on the material and / or thickness of each film. The above preset absorbance threshold can be set according to actual needs and is not limited here.

[0050] The above-mentioned near-infrared high-reflection structural color filter adopts two continuous asymmetric optical resonant cavities (i.e., the first optical resonant cavity and the second optical resonant cavity) and the anti-reflection layer 107 on the top, and produces constructive interference phenomenon for visible light within the required target color wavelength range in the two continuous asymmetric optical resonant cavities, and optically absorbs visible light within the non-target color wavelength range. The absorption is enhanced by multi-cavity resonance, and the reflection of visible light within the non-target color wavelength range is fully suppressed. The first absorption layer 104 and the second absorption layer 106 have low absorption rates for near-infrared light, ensuring the high reflectivity of near-infrared light. Therefore, the near-infrared high-reflection structural color filter achieves high-purity and high-brightness colors in the visible light range, and realizes the cooling function by utilizing the high reflectivity of the near-infrared band. At the same time, this multi-layer thin film structure is easy to prepare, low-cost, and simple in process.

[0051] Optionally, the substrate 101 may be made of quartz, silicon or glass, etc. It has good mechanical strength and flatness, and can ensure the uniformity of the reflective layer 102 .

[0052] Optionally, in order to ensure high brightness of the color, the reflectivity of the reflective layer 102 is greater than 90%.

[0053] Optionally, the reflective layer 102 may be a metal layer, and the material of the reflective layer 102 may include aluminum, copper, gold, platinum, palladium or silver, etc. These materials have high reflectivity in the visible light and near infrared spectrum.

[0054] Furthermore, the material of the reflective layer 102 is aluminum, and the thickness of the reflective layer 102 is greater than 70 nm, for example, the thickness of the reflective layer 102 is 100 nm. This ensures that the reflectivity of the reflective layer 102 reaches more than 90%, thereby ensuring high brightness of the color; at the same time, the chemical properties of the reflective layer 102 are stable and the cost is low.

[0055] Optionally, the material of the first dielectric layer 103, the material of the second dielectric layer 105 and the material of the anti-reflection layer 107 all include at least one of niobium titanium oxide, silicon dioxide, silicon oxynitride, aluminum oxide, titanium dioxide, niobium pentoxide, tantalum pentoxide, zirconium oxide, yttrium oxide, hafnium dioxide, silicon nitride, zinc selenide, tungsten oxide and zinc sulfide. Aluminum oxide, silicon nitride and silicon dioxide are easy to prepare; titanium dioxide, zirconium oxide, zinc selenide and zinc sulfide have high refractive index and angle insensitivity (the angle here refers to the angle between the line of sight and the normal line of the filter surface). It should be noted that the materials of the first dielectric layer 103, the second dielectric layer 105 and the anti-reflection layer 107 can be the same or different, and are not limited to the above materials.

[0056] Optionally, in order to further improve the color purity, the reflectivity of the first absorption layer 104 and the second absorption layer 106 to visible light within the target color wavelength range is greater than the reflectivity to visible light within the non-target color wavelength range.

[0057] Optionally, the material of the first absorption layer 104 and the material of the second absorption layer 106 may both include germanium or silicon. The optical loss of germanium in the visible light range helps to absorb unwanted reflections, thereby generating high-purity colors; and ensures high NIR (Near-Infrared) reflectivity, because germanium has a low absorption rate in the long-wave range above 800 nanometers, that is, it has high transparency relative to the near-infrared band.

[0058] Each layer of the above-mentioned near-infrared high-reflection structural color filter can be prepared by electron beam evaporation equipment, inductively coupled plasma enhanced vapor deposition equipment, thermal evaporation equipment or magnetron sputtering, etc., or can be prepared by combining multiple equipments therein. It should be noted that the embodiment of the present invention does not limit the preparation equipment corresponding to each layer, and in other embodiments, chemical vapor deposition equipment can also be used.

[0059] Optionally, the reflective layer 102 is made of aluminum, the first absorption layer 104 and the second absorption layer 106 are both made of germanium, and the reflective layer 102, the first absorption layer 104 and the second absorption layer 106 are all prepared by electron beam evaporation equipment or thermal evaporation equipment.

[0060] Furthermore, the material of the first dielectric layer 103, the material of the second dielectric layer 105 and the material of the anti-reflection layer 107 are all silicon nitride, and the first dielectric layer 103, the second dielectric layer 105 and the anti-reflection layer 107 are all prepared by using an inductively coupled plasma enhanced vapor deposition device. This has a simple preparation process, low cost, and good cleanliness and flatness.

[0061] In one possible implementation, Figure 2 and Figure 3 As shown, the above-mentioned near-infrared high-reflection structural color filter can be obtained in the following manner: using electron beam evaporation equipment and inductively coupled plasma enhanced vapor deposition equipment, a dielectric-absorption layer-dielectric-absorption layer-dielectric-metal (DADADM) thin film structure is prepared on a quartz substrate in the order from top to bottom; wherein the metal layer is a 100nm thick layer of aluminum (Al) deposited on the quartz substrate, and the metal layer serves as a reflective layer. Al is selected as the bottom layer here because it has high reflectivity in the visible and near-infrared spectral range. Silicon nitride (Si3N4) is selected as the dielectric layer because of its high refractive index and is used as a spacer layer and an anti-reflection (AR) layer on the top. Germanium (Ge) is used as the absorption layer. Ge is selected here because: (1) its optical loss in the visible light range helps to absorb unwanted reflections, thereby generating high-purity colors; (2) it ensures high NIR reflectivity because it has high transparency in the long-wave range above 800nm. Electron beam evaporation equipment is used to prepare Al and Ge, and inductively coupled plasma enhanced vapor deposition equipment is used to prepare Si3N4. The process is simple, the cost is low, and the cleanliness and flatness are good. Constructive interference occurs in two consecutive asymmetric FP cavities for the desired wavelength, and the non-target color wavelength is optically absorbed by the absorption layer.

[0062] In an embodiment of the present invention, a near-infrared high-reflection structural color filter with high purity and high brightness is realized by using two continuous asymmetric FP cavities and an anti-reflection layer on the top. Different colors are obtained by adjusting the thickness of the film, and the semiconductor material (Ge) as the absorption layer has different functions in different wavelength regions: in the visible light range, the absorption is enhanced by multi-cavity resonance, which fully suppresses unwanted reflections, so that it produces high-purity RGB colors, and the peak reflectivity exceeds 70%; the intrinsic low-loss characteristics of the wavelength>800nm ​​region ensure broadband reflection in the entire near-infrared range, and the average efficiency is greater than 80%. In addition, the near-infrared high-reflection structural color filter can maintain color unchanged and high NIR reflection characteristics within the angle range of ±50° (blue and red) and the angle range of ±40° (green), thereby achieving an aesthetic effect and having a near-infrared cooling function.

[0063] In addition, the near-infrared high-reflection structural color filter has low cost, simple process, and is easier to be widely used, especially in decoration and solar coolers, and has great application potential.

[0064] Exemplarily, the thickness of each film corresponding to the three colors is shown in Table 1 below.

[0065] Table 1

[0066]

[0067] Different colors require different film thicknesses, and the adjustment range of the film thickness value is ±2nm to ensure the purity of the color.

[0068] Figure 4 The corresponding reflection spectrum of a blue near-infrared high-reflection structural color filter is shown. Figure 5 The corresponding reflection spectrum of a green near-infrared high-reflection structural color filter is shown. Figure 6 The corresponding reflection spectrum of a red near-infrared high-reflection structural color filter is shown in FIG. Figures 4 to 6 As shown, the experimental results are consistent with the simulation results. The peak of blue light is around 450nm, the peak of green light is around 500nm, and the peak of red light is 600nm and above (but near-infrared light is not perceptible to the human eye).

[0069] like Figure 7 As shown, among the three color samples observed at four different angles, the blue and red colors can remain unchanged within the angle range of ±50°, and the green color can remain unchanged within the angle range of ±40°.

[0070] The present invention also provides a method for preparing the above-mentioned near-infrared high-reflection structural color filter, see Figure 8The schematic diagram of the process of preparing a near-infrared high-reflection structural color filter is shown, and the preparation method mainly includes the following steps S801 to S806:

[0071] Step S801, forming a reflective layer on a substrate;

[0072] Step S802, forming a first dielectric layer on the reflective layer;

[0073] Step S803, forming a first absorption layer on the first dielectric layer;

[0074] Step S804, forming a second dielectric layer on the first absorption layer;

[0075] Step S805, forming a second absorption layer on the second dielectric layer;

[0076] Step S806: forming an anti-reflection layer on the second absorption layer.

[0077] The preparation method provided in this embodiment has the same implementation principle and technical effects as those of the aforementioned near-infrared high-reflection structural color filter embodiment. For the sake of brief description, for matters not mentioned in the preparation method embodiment, reference may be made to the corresponding contents in the aforementioned near-infrared high-reflection structural color filter embodiment.

[0078] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0079] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A near-infrared high-reflection structural color filter, characterized in that: It comprises a substrate and a reflection layer, a first dielectric layer, a first absorption layer, a second dielectric layer, a second absorption layer and an anti-reflection layer which are sequentially formed on the substrate; The reflective layer, the first dielectric layer and the first absorption layer constitute a first optical resonant cavity, and the first absorption layer, the second dielectric layer and the second absorption layer constitute a second optical resonant cavity; the first absorption layer and the second absorption layer both have an absorptivity of visible light within a target color wavelength range that is lower than an absorptivity of visible light within a non-target color wavelength range, and an absorptivity of near-infrared light that is lower than a preset absorptivity threshold.

2. The near-infrared high-reflection structural color filter according to claim 1, characterized in that: The reflectivity of the reflective layer is greater than 90%.

3. The near-infrared high-reflection structural color filter according to claim 2, characterized in that: The material of the reflective layer includes aluminum, copper, gold, platinum, palladium or silver.

4. The near-infrared high-reflection structural color filter according to claim 3, characterized in that: The reflective layer is made of aluminum, and the thickness of the reflective layer is greater than 70 nm.

5. The near-infrared high-reflection structural color filter according to claim 1, characterized in that: The material of the first dielectric layer, the material of the second dielectric layer and the material of the anti-reflection layer all include at least one of niobium titanium oxide, silicon dioxide, silicon oxynitride, aluminum oxide, titanium dioxide, niobium pentoxide, tantalum pentoxide, zirconium oxide, yttrium oxide, hafnium dioxide, silicon nitride, zinc selenide, tungsten oxide and zinc sulfide.

6. The near-infrared high-reflection structural color filter according to claim 1, characterized in that: The reflectivity of the first absorption layer and the second absorption layer to visible light within the target color wavelength range is greater than the reflectivity to visible light within the non-target color wavelength range.

7. The near-infrared high-reflection structural color filter according to claim 6, characterized in that: The material of the first absorption layer and the material of the second absorption layer both include germanium or silicon.

8. The near-infrared high-reflection structural color filter according to claim 1, characterized in that: The reflective layer is made of aluminum, and the first absorption layer and the second absorption layer are both made of germanium.

9. The near-infrared high-reflection structural color filter according to claim 8, characterized in that: The material of the first dielectric layer, the material of the second dielectric layer and the material of the anti-reflection layer are all silicon nitride.

10. A method for preparing a near-infrared high-reflection structural color filter according to any one of claims 1 to 9, characterized in that: include: forming the reflective layer on the substrate; forming the first dielectric layer on the reflective layer; forming the first absorption layer on the first dielectric layer; forming the second dielectric layer on the first absorption layer; forming the second absorption layer on the second dielectric layer; The anti-reflection layer is formed on the second absorption layer.

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