A red metallic dielectric structural color film

Abstract

The present invention relates to the technical field of structural color materials, and specifically, to a red metal dielectric structural color film. It includes from bottom to top: a substrate, a reflective metal layer, a dielectric layer, a semi-transparent metal layer and a top admittance matching layer. In the present invention, the reflective layer metal has stable chemical properties and high reflectivity properties; the dielectric layer has stable chemical properties, high refractive index and low visible light absorption properties; the semi-transparent metal has neutral metal properties, and the refractive index and extinction coefficient are close; the outermost admittance matching layer realizes the low reflection property of short-wave visible light. The present invention realizes high reflection in the red band of 650nm-700nm, and presents a high-saturation red effect as a whole. In the present invention, the substrate, the reflective metal layer, the dielectric layer, the semi-transparent metal layer and the top admittance matching layer all provide a variety of materials for flexible selection; keeping the structure and materials unchanged, only the thickness of the film layer needs to be fine-tuned to obtain red with different saturations, and the structure is highly versatile.

Description

Technical Field

[0001] The invention relates to the technical field of structural color materials, and in particular to a red metal dielectric structural color film. Background Art

[0002] Many organisms in nature have evolved fine photonic nanostructures in a hierarchical and organized manner at multiple scales and dimensions, presenting brilliant colors through interference, diffraction and scattering of light. This color-developing mechanism in which color is generated by structure is called physical color. It relies on the micro-nanostructure inside the material to precisely control the absorption, reflection or transmission in the visible spectrum to produce specific colors, also known as structural colors. Compared with traditional chemical coloring technologies such as organic dyes and chemical pigments, structural colors have unique advantages such as high saturation, high brightness, long life, and green environmental protection. Therefore, they have important application value in the fields of optical imaging / display / detection devices, anti-counterfeiting, car films, color decoration, optical filters, etc.

[0003] In recent years, with the in-depth study of structural colors, researchers have successively developed structural colors based on different metasurfaces and physical resonance mechanisms, such as Guided Mode Resonance (GMR), Surface Plasmon Resonance (SPR), Mie Resonance and other ideas. However, the above preparations often have disadvantages such as time-consuming, high cost, and complicated procedures. In contrast, one-dimensional photonic crystal multilayer films based on optical interference effects are the main technical method for achieving structural colors, and are also the preferred solution for achieving structural colors in the industrial field. This thin film structural color is affected by the film material, film structure, film thickness or film period number, etc. If one factor changes, the color will also change. However, the existing structural color films are limited by various factors such as preparation technology, FP structure itself or materials, which makes the structural color chromaticity performance unsatisfactory, and has no advantages in manufacturing cost and large-scale manufacturing. Among the various color filtering schemes currently available, due to the limitation of the long-wave red band, achieving highly saturated red has always been a difficult problem in structural color research. Therefore, people hope to develop a red structural color film that has both high saturation and simple structure and preparation process.

[0004] In the related patents CN111761897A and CN112505813A, all-dielectric films and in CN113759454A, all-silicon materials are used to realize structural color films, but both involve relatively complex film structures, require stacking thicker film layers, and the effect of realizing red structural colors is not ideal. In the related patent CN105137518A, it is proposed to use metal dielectric metal films to realize transmissive color filters. Based on the adjustable refractive index characteristics of the dielectric film, specific absorption of the visible light band is achieved through a specific structure to achieve a higher transmittance in a specific band, and its peak transmittance is only about 40%. In the related patents CN103744138A and CN110412672B, nano-circular hole arrays or nano-cylinder arrays are used to couple and resonate visible light on the surface of the material, achieving high reflection and high absorption, thereby displaying a specific color. However, such methods often require the use of very complex preparation processes such as reactive ion etching, wet etching, atomic layer deposition, and photolithography. In contrast, structural color films can be obtained only through electron beam evaporation, which is simple to prepare, low-cost, environmentally friendly, and more likely to be mass-produced.

[0005] At present, the use of metal media to achieve red structural color films has not been researched and developed. Considering that this method has the advantages of low preparation cost, high process difficulty, and high saturation, it also solves the problem of difficulty in designing highly saturated red structural colors. It has important application value in the fields of automotive films, printing, coatings, optical displays, photoelectric detection, etc. Summary of the invention

[0006] The object of the present invention is to provide a red metal dielectric structural color film to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides a red metal dielectric structural color film, which includes from bottom to top: a substrate, a reflective metal layer, a dielectric layer, a semi-transparent metal layer and a top admittance matching layer. For details, please refer to Figure 1 Schematic diagram of the structure shown.

[0008] As a further improvement of the technical solution, the substrate is one of polyvinylidene fluoride, polytetrafluoroethylene, stainless steel, K9 glass, calcium fluoride glass, fluoroethylpropylene, polypropylene, polyvinyl chloride and polycarbonate;

[0009] The substrate is wiped clean with a mixture of alcohol and acetone in a ratio of 7:3 to ensure the density and adhesion of the film layer.

[0010] As a further improvement of the technical solution, the metal reflective layer is made of an alloy composed of one or more of gold, silver, aluminum, tin, platinum and aluminum-silicon-copper alloy, and the reflective metal layer has stable chemical properties and high reflectivity properties.

[0011] As a further improvement of the technical solution, the dielectric layer is made of one of aluminum oxide, aluminum nitride and aluminum oxynitride, and the dielectric layer has stable chemical properties, high refractive index and low visible light absorption properties.

[0012] As a further improvement of the technical solution, the semi-transparent metal layer is made of an alloy composed of one or more of silicon, hafnium, germanium and niobium. The semi-transparent metal layer has neutral metal properties, and its refractive index and extinction coefficient are close.

[0013] As a further improvement of the technical solution, the top admittance matching layer adopts one of carbon and silicon or a combination of the two, and the top admittance matching layer can achieve low reflection characteristics of short-wave visible light.

[0014] As a further improvement of the technical solution, a red metallic dielectric structural color film is prepared by a dry deposition method or a wet deposition method; wherein:

[0015] Dry deposition includes physical vapor deposition and chemical vapor deposition; wherein the physical vapor deposition includes magnetron sputtering deposition, electron beam evaporation, ion beam sputtering deposition and a combination of electron beam evaporation and ion assisted deposition;

[0016] Wet deposition includes sol-gel process, wet chemical deposition process and spin coating process.

[0017] The red structural color film of the present invention patent specifically uses aluminum-silicon-copper alloy, aluminum oxynitride, hafnium-silicon alloy, and carbon film. The reflective metal layer uses aluminum-silicon-copper alloy, and the physical thickness is set to 100nm. Its function is to provide a higher reflectivity; at the same time, it absorbs short waves that have a greater impact on the color purity of red, thereby improving the color purity of red. The dielectric layer uses aluminum oxynitride, which has stable chemical properties, low visible light absorption properties, and a high refractive index (1.7-1.8). It can produce a strong constructive interference effect in the red band of 650nm-700nm, and ultimately achieve high reflection in the red band. The semi-transparent metal layer uses hafnium-silicon alloy. The refractive index of this material in the visible light band is about 3.2-3.3, and the extinction coefficient is about 2.0. The refractive index and extinction coefficient are close, and it has neutral metal characteristics, which further reduces short-wave residual reflection and improves color purity. The top absorption layer uses a carbon film to achieve short-wave admittance matching, further reducing the residual reflection in the 400nm-600nm band, and ultimately presenting a highly saturated red color characteristic.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In this red series metal dielectric structural color film, metal dielectric is innovatively used to construct a thin film structural color device. The reflective layer metal of the device has stable chemical properties and high reflectivity characteristics; the dielectric layer has stable chemical properties, high refractive index and low visible light absorption characteristics; the semi-transparent metal has neutral metal characteristics, and the refractive index and extinction coefficient are close; the outermost admittance matching layer realizes the low reflection characteristics of short-wave visible light. The present invention achieves high reflection in the red band of 650nm-700nm, with a reflectivity of 50%-70%, and reduces the reflectivity of the 400nm-580nm blue, green and yellow spectral bands to less than 10%, presenting a high saturation red effect as a whole. In addition, in this design, the substrate, reflective metal layer, dielectric layer, semi-transparent metal layer and top admittance matching layer all provide a variety of materials for flexible selection; in addition, keeping the structure and materials unchanged, only the thickness of the film layer needs to be fine-tuned to obtain reds of different saturations, and the structure is highly versatile. Compared with previous studies, this solution has the advantages of being green and environmentally friendly, low cost, no need for complex processes, and easy large-scale production. It has good application prospects in the fields of light display, color decoration, and anti-counterfeiting. It is expected to serve as a new green coloring strategy to replace traditional chemical dyes, providing a novel implementation solution for green and environmentally friendly printing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the metal dielectric structural color film of the present invention;

[0021] Figure 2 Schematic diagram of the structure of the reflective metal layer, the dielectric layer, the semi-transparent metal layer and the top admittance matching layer in Embodiments 1, 2 and 3 of the present invention;

[0022] Figure 3 Schematic diagram of optical constants of materials used for the reflective metal layer, dielectric layer, semi-transparent metal layer and top admittance matching layer in Examples 1, 2 and 3 of the present invention;

[0023] Figure 4 This is the optical admittance diagram of Example 1 of the present invention without adding a top AR layer;

[0024] Figure 5 The optical admittance diagram of Example 1 of the present invention with a top AR layer added;

[0025] Figure 6 The reflection spectra and simulated color diagram of Examples 1, 2, and 3 of the present invention at an incident angle of 0°;

[0026] Figure 7 1 is a chromaticity coordinate diagram of embodiments 1, 2 and 3 of the present invention at an incident angle of 0°.

[0027] The meaning of each number in the figure is:

[0028] 1. Substrate; 2. Reflective metal layer; 3. Dielectric layer; 4. Semi-transparent metal layer; 5. Top admittance matching layer. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] See also Figure 2 and Figure 3 As shown, this embodiment provides a positive red structural color film multilayer structure, which includes a substrate 1, a reflective metal layer 2, a dielectric layer 3, a semi-transparent metal layer 4 and a top admittance matching layer 5 from bottom to top. The specific thickness of each layer is given in Table 1. According to the thickness values ​​given in Table 1, a positive red structural color film can be prepared; the substrate 1 is selected from K9 glass with a thickness of 2 mm and a diameter of 80 mm, the reflective metal layer 2 is selected from aluminum silicon copper alloy (AlCuSi), the dielectric layer 3 is selected from aluminum oxynitride (AlON), the semi-transparent metal layer 4 is selected from hafnium silicon alloy (HfSi), and the top admittance matching layer 5 is selected from carbon (C) film; Figure 6 The corresponding reflection spectrum and simulation color are red. In the optical admittance diagram, the closer the distance between the end point of the admittance and (1,0) is, the smaller the reflectivity of the point is. Figure 4 and Figure 5 The admittance diagrams at three wavelengths of 430nm, 496nm, and 560nm are respectively shown in the embodiment with and without the admittance matching layer 5. The black solid line in the figure is the distance between the end point of the admittance trajectory and the air admittance (1,0), and the red five-pointed star is the end point of the admittance trajectory, which can be seen in the above three bands. When there is no AR, the black solid lines are longer, and after adding AR, the end point of the admittance trajectory almost coincides with (1,0). This shows that the structural design can significantly reduce the reflectivity of non-target bands and obtain a highly saturated red color, that is, true red. The chromaticity coordinates (x, y) of the true red color are calculated to be (0.6120, 0.3252). The red color of this design is very close to the standard red chromaticity coordinates (0.6400, 0.3300) used in liquid crystal displays, as shown in Figure 2. Figure 7 as shown in .

[0032] Table 1

[0033] Number of layers Reflective metal layer Dielectric layer Semi-transparent metal layer Top admittance matching layer Material AlCuSi AlON HkDJ C Physical thickness (nm) 100 142 33 35

[0034] Example 2

[0035] like Figure 2 and Figure 3 As shown, this embodiment provides an orange-red structural color thin film multilayer structure, which includes, from bottom to top, a substrate 1, a reflective metal layer 2, a dielectric layer 3, a semi-transparent metal layer 4 and a top admittance matching layer 5, and the specific thickness of each layer is given in Table 2. The substrate 1 is made of K9 glass with a thickness of 2 mm and a diameter of 80 mm, the reflective metal layer 2 is made of aluminum silicon copper alloy (AlCuSi), the dielectric layer 3 is made of aluminum oxynitride (AlON), the semi-transparent metal layer 4 is made of hafnium silicon alloy (HfSi), and the top admittance matching layer 5 is made of carbon (C) film. An orange-red structural color film can be prepared according to the thickness values ​​given in Table 2. On the basis of the true red color, without changing the structure and materials, fine-tuning the thickness of the dielectric layer 3, the transparent metal layer, and the top admittance matching layer 5 can obtain an orange-red color, that is, an orange-red color. As shown in Table 2 Figure 6 and Figure 7 The reflection spectrum, simulated color and chromaticity coordinates of the structural design are displayed. Calculation shows that the reflection peak is at a wavelength of 625nm, the reflectivity is about 66%, and the chromaticity coordinates are (0.5714, 0.3533).

[0036] Table 2

[0037] Number of layers Reflective metal layer Dielectric layer Semi-transparent metal layer Top admittance matching layer Material AlCuSi AlON HkDJ C Physical thickness (nm) 100 141 24 34

[0038] Example 3

[0039] like Figure 2 and Figure 3 As shown, a magenta structural color film multilayer structure includes, from bottom to top, a substrate 1, a reflective metal layer 2, a dielectric layer 3, a semi-transparent metal layer 4 and a top admittance matching layer 5, and the specific thickness of each layer is given in Table 3. The substrate 1 is made of K9 glass with a thickness of 2 mm and a diameter of 80 mm, the reflective metal layer 2 is made of aluminum silicon copper alloy (AlCuSi), the dielectric layer 3 is made of aluminum oxynitride (AlON), the semi-transparent metal layer 4 is made of hafnium silicon alloy (HfSi), and the top admittance matching layer 5 is made of carbon (C) film. The purpose of setting each layer is consistent with the true red color in Example 1. A magenta structural color film can be prepared according to the thickness values ​​given in Table 3. On the basis of the true red color, without changing the structure and materials, fine-tuning the thickness of the dielectric layer 3, the transparent metal layer, and the top admittance matching layer 5 can obtain a pink red color, that is, magenta. As shown in Table 3 Figure 6 and Figure 7 The reflection spectrum, simulated color and chromaticity coordinates of the structural design are displayed. Calculation shows that the reflection peak is at 670nm, the reflectivity is about 66%, and the chromaticity coordinates are (0.5481, 0.2984).

[0040] Table 3

[0041] Number of layers Reflective metal layer Dielectric layer Semi-transparent metal layer Top Admittance Matching Layer Material AlCuSi AlON HkDJ C Physical thickness (nm) 100 152 25 35

[0042] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A red metallic dielectric structural color film, characterized in that: From bottom to top, this includes: A substrate (1), a reflective metal layer (2), a dielectric layer (3), a semi-transparent metal layer (4) and a top admittance matching layer (5); The reflective metal layer (2) is made of an alloy composed of one or more of gold, silver, aluminum, tin, platinum and aluminum-silicon-copper alloy; The dielectric layer (3) is made of one of aluminum oxide, aluminum nitride and aluminum oxynitride; The semi-transparent metal layer (4) is an alloy composed of one or more of silicon, hafnium, germanium and niobium; The top admittance matching layer (5) is made of carbon, silicon or a combination of the two.

2. The red metallic dielectric structural color thin film according to claim 1, characterized in that: The substrate (1) is made of one of polyvinylidene fluoride, polytetrafluoroethylene, stainless steel, K9 glass, calcium fluoride glass, fluoroethylpropylene, polypropylene, polyvinyl chloride and polycarbonate.

3. The red metallic dielectric structural color thin film according to claim 1, characterized in that: The red metal dielectric structural color film is prepared by dry deposition or wet deposition method, specifically: Dry deposition includes physical vapor deposition and chemical vapor deposition; wherein the physical vapor deposition includes magnetron sputtering deposition, electron beam evaporation, ion beam sputtering deposition and a combination of electron beam evaporation and ion assisted deposition; Wet deposition includes sol-gel process, wet chemical deposition process and spin coating process.

4. The red metallic dielectric structural color thin film according to claim 1, characterized in that: The substrate (1) is wiped clean with a mixture of alcohol and acetone in a ratio of 7:3.

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