Omnidirectional structural color microstructures containing titanium dioxide

Abstract

A multilayer film that reflects omnidirectional structural color has a reflective core layer, an amorphous-phase TiO2 dielectric layer extending over the reflective core layer, a metallic absorbing layer extending over the dielectric layer, and a dielectric outer layer extending over the metallic absorbing layer, wherein the multilayer film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, and the color shift of the single narrow band of visible light, as measured in Lab color space, is less than 30° when the multilayer film is exposed to the broadband electromagnetic radiation and observed from an angle between 0° and 45° relative to a direction normal to the outer surface of the multilayer film.

Description

[Technical Field]

[0001] This application relates to multilayer thin film structures, and in particular to multilayer thin film structures containing titanium dioxide that exhibit minimal or no noticeable color shift when exposed to broadband electromagnetic radiation and viewed from various angles. [Background technology]

[0002] Pigments made from multilayer structures are known. Furthermore, pigments that exhibit or provide highly saturated omnidirectional structural colors are also known. However, forming multilayer structures from certain materials can be difficult because deposition techniques for depositing various materials can adversely affect previously deposited materials. Furthermore, certain deposition techniques can be costly and time-consuming, making it very difficult to achieve commercially viable multilayer structures.

[0003] It is recognized that the color produced by a multilayer thin film structure depends on the materials used as the various layers, the location of the materials within the multilayer thin film structure, and the properties (e.g., thickness) of the individual layers. Therefore, small variations in the design of the multilayer thin film structure can have a clearly discernible effect on the color produced by the multilayer thin film structure. However, conventional deposition techniques are not always effective in depositing the desired layers within the multilayer thin film structure to achieve the best combination for an omnidirectional multilayer thin film. Summary of the Invention [Problem to be solved by the invention]

[0004] According to an embodiment, a multilayer film that reflects omnidirectional structural color includes a reflective core layer, an amorphous phase TiO dielectric layer extending over the reflective core layer, a metallic absorbing layer extending over the amorphous phase TiO dielectric layer, and a dielectric outer layer extending over the metallic absorbing layer, wherein the multilayer film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, the single narrow band of visible light comprising a color shift of the single narrow band of visible light that is less than 30° as measured in Lab color space when the multilayer film is exposed to broadband electromagnetic radiation and viewed from an angle between 0° and 45° relative to a direction normal to an outer surface of the multilayer film.

[0005] In some embodiments, a multilayer film that reflects omnidirectional structural color includes a reflective core layer, a protective layer encapsulating the reflective core layer, an amorphous phase TiO dielectric layer extending over at least a portion of the protective layer, a metal absorbing layer extending over the amorphous phase TiO dielectric layer, and a dielectric outer layer extending over the metal absorbing layer, wherein the multilayer film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, the single narrow band of visible light comprising a color shift of the single narrow band of visible light that is less than 30° as measured in Lab color space when the multilayer film is exposed to broadband electromagnetic radiation and observed from an angle between 0° and 45° relative to a direction normal to an outer surface of the multilayer film.

[0006] In some embodiments, a multilayer film that reflects omnidirectional structural color includes a reflective core layer, a protective layer encapsulating the reflective core layer, an amorphous phase TiO dielectric layer extending over at least a portion of the protective layer, a barrier layer extending over the amorphous phase TiO layer, a metal absorbing layer extending over the barrier layer, and a dielectric outer layer extending over the metal absorbing layer, wherein the multilayer film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, the single narrow band of visible light comprising a color shift of the single narrow band of visible light that is less than 30° as measured in Lab color space when the multilayer film is exposed to broadband electromagnetic radiation and viewed from an angle between 0° and 45° relative to a direction normal to an outer surface of the multilayer film.

[0007] In some embodiments, a multilayer film that reflects omnidirectional structural color includes a reflective core layer, an amorphous phase TiO2 dielectric layer extending over at least a portion of the reflective core layer, a barrier layer extending over the amorphous phase TiO2 dielectric layer, a metal absorbing layer extending over the barrier layer, and a dielectric outer layer extending over the metal absorbing layer, wherein the multilayer film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, the single narrow band of visible light comprising a color shift of the single narrow band of visible light that is less than 30° as measured in Lab color space when the multilayer film is exposed to broadband electromagnetic radiation and observed from an angle between 0° and 45° relative to a direction normal to an outer surface of the multilayer film.

[0008] According to another embodiment, a method of forming a multilayer thin film includes depositing an amorphous phase TiO2 dielectric layer on a reflective core layer by CVD or ALD, depositing a metal absorber layer on the amorphous phase TiO2 dielectric layer by ALD, and depositing a dielectric outer layer on the metal absorber layer by CVD or ALD.

[0009] In some embodiments, a method of forming a multilayer thin film includes depositing a protective layer on a reflective core layer by a wet chemical process, depositing an amorphous phase TiO dielectric layer on the protective layer by CVD or ALD, depositing a metal absorber layer on the amorphous phase TiO dielectric layer by ALD, and depositing a dielectric outer layer on the metal absorber layer by CVD or ALD.

[0010] In some embodiments, a method of forming a multilayer thin film includes depositing a protective layer on a reflective core layer by a wet chemical process, depositing an amorphous phase TiO dielectric layer on the protective layer by CVD or ALD, depositing a barrier layer on the amorphous phase TiO dielectric layer, depositing a metal absorber layer on the barrier layer by ALD, and depositing a dielectric outer layer on the metal absorber layer by CVD or ALD.

[0011] According to another embodiment, a method of forming a multilayer thin film includes depositing an amorphous phase TiO dielectric layer on a reflective core layer by CVD or ALD, depositing a barrier layer on the amorphous phase TiO dielectric layer by ALD, depositing a metal absorber layer on the barrier layer by ALD, and depositing a dielectric outer layer on the metal absorber layer by CVD or ALD.

[0012] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the detailed description, or may be learned by practicing the embodiments described in this disclosure, including the following detailed description, the claims, and the accompanying drawings.

[0013] It is to be understood that both the foregoing general description and the following detailed description are intended to describe various embodiments and provide an overview or framework for understanding the nature and features of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments described in the present disclosure and, together with the detailed description, serve to explain the principles and operation of the claimed subject matter. [Brief explanation of the drawings]

[0014] [Figure 1] 1A and 1B are schematic cross-sectional views of multilayer thin film structures according to embodiments disclosed and described herein.

[0015] [Figure 2A] FIG. 2A shows a multilayer film having a dielectric layer extending over a reflective core layer used in the multilayer film design.

[0016] [Figure 2B] FIG. 2B shows a multilayer film having a semiconductor absorbing layer extending over a reflective core layer used in the multilayer film design.

[0017] [Figure 2C] FIG. 2C illustrates a multilayer film having a dielectric absorbing layer extending over a reflective core layer for use in the design of a multilayer film according to one or more embodiments disclosed and described herein.

[0018] [Figure 3] FIG. 3 shows the reflection characteristics in the Lab color space of the multilayer thin film shown in FIGS. 2A to 2C.

[0019] [Figure 4A] FIG. 4A graphically illustrates saturation and hue values ​​as a function of dielectric layer thickness for the multilayer thin film shown in FIG. 2A.

[0020] [Figure 4B] FIG. 4B graphically illustrates saturation and hue values ​​as a function of semiconductor absorber layer thickness for the multilayer thin film shown in FIG. 2B.

[0021] [Figure 4C] FIG. 4C graphically illustrates saturation and hue values ​​as a function of the thickness of the dielectric absorbing layer of the multilayer thin film shown in FIG. 2C.

[0022] [Figure 5] FIG. 5 is a magnified image of the rutile phase TiO2 dielectric layer deposited on the protective layer.

[0023] [Figure 6] FIG. 6 shows a magnified image of a rutile phase TiO2 dielectric layer deposited on a protective layer, a metal absorber layer deposited on the rutile phase TiO2 dielectric layer, and a dielectric outer layer deposited on the metal absorber layer.

[0024] [Figure 7] FIG. 7 shows enlarged images of an amorphous phase TiO2 dielectric layer deposited on a protective layer, a metal absorbing layer deposited on the amorphous phase TiO2 dielectric layer, and a dielectric outer layer deposited on the metal absorbing layer.

[0025] [Figure 8]FIG. 8 shows a multilayer thin film in which a dielectric layer extends over a substrate layer and is exposed to electromagnetic radiation at an angle θ relative to a direction normal to the outer surface of the dielectric layer.

[0026] [Figure 9A] FIG. 9A graphically illustrates the reflectance curves of the examples provided herein. [Figure 9B] FIG. 9B graphically illustrates the reflectance curves of the examples provided herein. [Figure 9C] FIG. 9C graphically illustrates the reflectance curves of the examples provided herein. [Figure 9D] FIG. 9D graphically illustrates the reflectance curves of the examples provided herein. [Figure 9E] FIG. 9E graphically illustrates the reflectance curves of the examples provided herein.

[0027] [Figure 10A] FIG. 10A graphically illustrates the reflectance curves of the examples provided herein. [Figure 10B] FIG. 10B graphically illustrates the reflectance curves of the examples provided herein. [Figure 10C] FIG. 10C graphically illustrates the reflectance curves of the examples provided herein. [Figure 10D] FIG. 10D graphically illustrates the reflectance curves of the examples provided herein. [Figure 10E] FIG. 10E graphically illustrates the reflectance curves of the examples provided herein. [Figure 10F] FIG. 10F graphically illustrates the reflectance curves of the examples provided herein. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present disclosure provides a structure that produces omnidirectional structural color. The structure produces omnidirectional structural color in the form of a multilayer thin film (also referred to herein as a multilayer stack) that reflects a narrow band of electromagnetic radiation in the visible spectrum, with a small or insignificant hue shift when the multilayer thin film is viewed from an angle of 0 to 45 degrees. The multilayer thin film can be used as a pigment in a composition (e.g., a paint composition), as a continuous thin film on a structure, or the like.

[0029] Fabricating omnidirectional structural color multilayer thin films can be a complex and expensive process, in part because very tight control of layer thickness is required. The deposition methods used to deposit the layers can vary in complexity and cost, depending on the materials that make up a given layer and the layer's desired thickness. Therefore, a variety of materials that can be deposited by a variety of deposition techniques is desirable.

[0030] However, because these methods require highly acidic or basic conditions, it can be difficult to deposit layers directly onto a reflective core layer, such as an aluminum (Al) reflective core layer, using less expensive wet chemical methods. Furthermore, depositing precisely controlled, ultrathin absorber layers is challenging except by vacuum coating methods. In the present disclosure, a combination of deposition methods is used to reduce costs and still achieve the desired multilayer thin film structure. The use of TiO as the dielectric material allows for the use of a combination of wet chemical methods, atomic layer deposition (ALD), such as fluidized-bed ALD, and chemical vapor deposition (CVD), such as fluidized-bed CVD. For example, while ALD can precisely deposit thin layers, ALD is costly and time-consuming. CVD is less expensive and less time-consuming than ALD, but is not as precise as ALD and is not well suited to depositing very thin layers. While wet chemical methods are relatively fast and inexpensive, they are not efficient at depositing very thin layers and suffer from the aforementioned problems of using acidic or basic conditions. Therefore, a combination of ALD, CVD, and wet chemical methods can be used in embodiments with TiO2 dielectric materials to form multilayer thin films at lower cost and with higher efficiency than using ALD alone.

[0031] The multilayer thin film structures described herein can be used to omnidirectionally reflect wavelengths of visible light over a range of angles of incidence or viewing angles (e.g., hues from 0° to 120°). As used herein, it will be understood that the terms "electromagnetic waves," "electromagnetic radiation," and "light" can interchangeably refer to various wavelengths of light incident on the multilayer thin film structures. Such light can have wavelengths in the ultraviolet (UV), infrared (IR), and visible portions of the electromagnetic spectrum.

[0032] Referring now to FIG. 1A, a multilayer thin film 100 according to an embodiment disclosed and described herein includes a reflective core layer 110, at least one dielectric layer 120 extending over the reflective core layer 110, at least one metal absorbing layer 130 extending over the at least one dielectric layer 120, and at least one dielectric outer layer 140 extending over the at least one metal absorbing layer 130.

[0033] In some embodiments, referring to FIG. 1B , the multilayer thin film 100 includes a reflective core layer 110, a protective layer 150 encapsulating the reflective core layer 110, at least one dielectric layer 120 extending over at least a portion of the protective layer 150, at least one barrier layer 160 extending over at least a portion of the at least one dielectric layer 120, at least one metal absorption layer 130 extending over the at least one barrier layer 160, and at least one dielectric outer layer 140 extending over the at least one metal absorption layer 130.

[0034] 2A-2C and 3, the effectiveness of different types of layers extending over the reflective core layer 110 in achieving a desired hue level in the red region of the visible light spectrum plotted or depicted on Lab color space is shown. FIG. 2A shows a ZnS dielectric layer 120a extending over the reflective core layer 110, FIG. 2B shows a Si semiconductor absorption layer 120b extending over the reflective core layer 110, and FIG. 2C shows an Fe2O3 dielectric absorption layer 120c extending over the reflective core layer 110. Simulations of the reflectivity from each multilayer film shown in FIGS. 2A-2c were performed as a function of various thicknesses of the dielectric layer 120a, the semiconductor absorption layer 120b, and the dielectric absorption layer 120c. The results of the simulations are shown in FIG. 3. * b * Plotted on the Lab color space, also known as a color map, each data point shown in Figure 3 provides the saturation and hue for a particular thickness of the dielectric layer for the multilayer thin film shown in Figure 2A, the semiconductor absorber layer for the multilayer thin film shown in Figure 2B, or the dielectric absorber layer for the multilayer thin film shown in Figure 2C.

number

[0035] Referring to Figures 4A-4C, saturation and hue are shown as a function of layer thickness. Specifically, Figure 4A graphically illustrates saturation and hue as a function of thickness for a ZnS dielectric layer extending over the Al reflective core layer shown in Figure 2A. Figure 4B illustrates saturation and hue as a function of thickness for a Si semiconductor absorber layer extending over the Al reflective core layer shown in Figure 2B. Figure 4C illustrates saturation and hue as a function of thickness for an Fe2O3 dielectric absorber layer extending over the Al reflective core layer shown in Figure 2C. The dotted lines in Figures 4A-4C correspond to desired hue values ​​between 10° and 30° in the Lab color space. Figures 4A-4C demonstrate that higher saturation values ​​within the 10° to 30° hue range are achieved for multilayer thin films having a dielectric absorber layer extending over the reflective core layer.

[0036] Referring again to FIG. 1A , a multilayer thin film 100 that reflects omnidirectional, highly saturated structural colors according to an embodiment is shown. The multilayer thin film 100 includes a reflective core layer 110, a dielectric absorbing layer 120 extending over the reflective core layer 110, a metal absorbing layer 130 extending over the dielectric absorbing layer 120, and a dielectric outer layer 140 extending over at least one of the metal absorbing layers 130. In embodiments, the “outer layer” has a free outer surface (i.e., an outer surface that is not in contact with an absorbing layer or with another dielectric layer that is not part of a protective coating). It should be understood that in embodiments, two dielectric absorbing layers 120, two metal absorbing layers 130, and two dielectric outer layers 140 can be disposed on either side of the reflective core layer 110, such that the reflective core layer 110 is a core layer sandwiched between a pair of dielectric absorbing layers 120, a pair of metal absorbing layers 130, and a pair of dielectric outer layers 140. Such a multilayer film, having a pair of dielectric absorbing layers 120, a pair of metal absorbing layers 130, and a reflective core layer 110 sandwiched between a pair of outer dielectric layers, can be referred to as a seven-layer thin film.

[0037] In an embodiment, the reflective core layer 110 has a thickness of 50 nm to 500 nm, for example, 100 nm to 500 nm, 150 nm to 500 nm, 200 nm to 500 nm, 250 nm to 500 nm, 300 nm to 500 nm, 350 nm to 500 nm, 400 nm to 500 nm, 450 nm to 500 nm, 50 nm to 450 nm, for example, 100 nm to 450 nm, 150 nm to 450 nm, 200 nm to 450 nm, 250 nm to 450 nm, 300 nm to 450 nm, 350 nm to 450 nm, 400 nm to 450 nm, 50 nm to 400 nm, for example, 100 nm to 400 nm, 150 nm to 400 nm, 200 nm to 400 nm, 250 nm to 400 nm, 300 nm The thickness may be 100 to 400 nm, 350 to 400 nm, 50 to 350 nm, for example, 100 to 350 nm, 150 to 350 nm, 200 to 350 nm, 250 to 350 nm, 300 to 350 nm, 50 to 300 nm, for example, 100 to 300 nm, 150 to 300 nm, 200 to 300 nm, 250 to 300 nm, 50 to 250 nm, for example, 100 to 250 nm, 150 to 250 nm, 200 to 250 nm, 50 to 200 nm, for example, 100 to 200 nm, 150 to 200 nm, 50 to 150 nm, for example, 100 to 150 nm or 50 to 100 nm.

[0038] In embodiments, the reflective core layer 110 may be made from at least one of a "gray metal" material such as Al, Ag, Pt, Sn, or a "colorful metal" material such as Au, Cu, brass, bronze, TiN, Cr, or a combination thereof.

[0039] According to embodiments, the at least one dielectric layer 120 can have a thickness of 10 to 150 nm, such as 25 nm to 150 nm, 50 nm to 150 nm, 75 nm to 150 nm, 100 nm to 150 nm, 125 nm to 150 nm, 10 nm to 125 nm, 25 nm to 125 nm, 50 nm to 125 nm, 75 nm to 125 nm, 100 nm to 125 nm, 10 nm to 100 nm, 25 nm to 100 nm, 50 nm to 100 nm, 75 nm to 100 nm, 10 nm to 75 nm, 25 nm to 75 nm, 50 to 75 nm, 10 nm to 50 nm, 25 nm to 50 nm, or 10 to 25 nm.

[0040] At least one dielectric layer 120 is TiO2 and can be deposited by CVD or atomic layer deposition (ALD) over the reflective core layer 110. Surprisingly, it has been discovered that a particular phase of TiO2 provides a dielectric layer 120 that allows for uniform deposition of subsequent layers.

[0041] It has been found that crystalline phase TiO, such as rutile and anatase phase TiO, is deposited on a substrate (e.g., the reflective core layer 110 or protective layer, as disclosed in more detail below) as an uneven, jagged layer. This uneven, jagged layer of crystalline phase TiO makes it difficult to deposit subsequent layers, making subsequent deposition of uniform layers extremely difficult. Without being bound by theory, it is believed that the crystalline structure of TiO makes it difficult or impossible to deposit smooth layers of crystalline phase TiO at the nanoscale, as required for the multilayer thin film structures of embodiments. For example, FIG. 5 shows a magnified image of a rutile phase TiO dielectric layer 501 deposited on a silica protective layer 502 disposed on a reflective core 503. In embodiments, the TiO layer can be deposited by a wet chemical process. As can be seen in FIG. 5, rutile-phase TiO 501 has a highly uneven, jagged surface when deposited at the nanoscale (approximately 200 nm). This results in a dielectric layer with a large surface area, making the deposition of subsequent layers very difficult and time-consuming. Furthermore, as shown in FIG. 6, the metal absorbing layer 601 deposited by ALD on the rutile-phase TiO dielectric layer 501 has a non-uniform thickness and surface similar to the topography of the rutile-phase TiO dielectric layer 501. It should be understood that the thickness variations and undulating surface of the metal absorbing layer 601 can significantly affect the electromagnetic radiation reflected from the multilayer thin film. Furthermore, the unevenness originating from the rutile-phase TiO dielectric layer 501 propagates to undulations in the dielectric outer layer 602. These undulations in the dielectric outer layer 602 can affect the electromagnetic radiation reflected by the multilayer thin film structure.

[0042] Referring now to FIG. 7, a multilayer thin film structure 700 fabricated using an amorphous-phase TiO dielectric layer is described. In FIG. 7, a SiO protective layer 702 is disposed on an Al reflective layer 701. An amorphous-phase TiO dielectric layer 703 is disposed on the protective layer. Compared to the rutile-phase TiO dielectric layer shown in FIGS. 5 and 6, the amorphous-phase TiO dielectric layer 703 shown in FIG. 7 has a smooth surface (i.e., no varying thickness or undulations) that allows subsequent layers to be easily and uniformly deposited. However, the amorphous-phase TiO dielectric layer, in embodiments, can have a relatively high degree of porosity, which allows some material from layers deposited thereon to infiltrate into the amorphous-phase TiO dielectric layer. When an optical layer, such as a metal absorber layer, is deposited on the amorphous-phase TiO dielectric layer, this infiltration can alter the optical properties of the multilayer thin film structure. Therefore, in embodiments, as shown in FIG. 7, a barrier layer 704 without significant optical properties can be deposited on the amorphous phase TiO dielectric layer to fill the pores before a metal absorbing layer 705 is deposited on the multilayer thin film structure. This barrier layer 704, in embodiments, is made of alumina (AlO) and has a thickness of 10 nm or less, such as 8 nm or less, 6 nm or less, 4 nm or less, or 2 nm or less, and can be deposited on the amorphous phase TiO dielectric layer by ALD. As shown in FIG. 7, a uniform and smooth tungsten metal absorbing layer 705 is deposited on the AlO barrier layer 704, and a uniform and smooth TiO dielectric outer layer 706 is deposited on the metal absorbing layer 705. The multilayer thin film structure 700 shown in FIG. 7 has layers with uniform thickness and minimal undulations, which provides uniform reflection of electromagnetic radiation.

[0043] To obtain an amorphous-phase TiO2 dielectric layer, the ALD or CVD method used to deposit the TiO2 dielectric layer should be performed at a temperature and pressure that does not allow TiO2 to crystallize and form the rutile or anatase phase. Without being bound by any particular theory, it is believed that the deposition temperature can help apply the amorphous phase of TiO2. For example, in embodiments where the TiO2 layer is deposited by CVD, the deposition temperature is less than 500°C, such as less than 475°C, less than 450°C, less than 425°C, or less than 400°C. In embodiments where the TiO2 layer is deposited by ALD, the deposition temperature is less than 180°C, such as less than 160°C, less than 140°C, or less than 120°C. Such application processes can provide dense layers with little porosity. The surface of such layers is smooth, with no roughness, no grain formation, and little porosity.

[0044] The metal absorbing layer 130 extends between the dielectric layer 120 and the dielectric outer layer 140, and the position of the metal absorbing layer 130 is selected to increase absorption of the targeted light wavelength. For example, if a multilayer thin film is configured to absorb electromagnetic radiation having a wavelength of 550 nm or less but reflect electromagnetic radiation having a wavelength of about 650 nm, such as visible light outside the 10°-30° hue, the absorbing layer may be configured to reduce the electric field (|E|) at a wavelength of 550 nm by more than at a wavelength of 650 nm. 2 ) is smaller. Mathematically, this can be expressed as:

[0045]

number

[0046] Preferably, it is as follows:

[0047]

number

[0048] 8 and the following discussion provide a method for calculating the thickness of a zero or near-zero electric field point at a given wavelength of light, according to an embodiment. For purposes of this specification, the term "near-zero" refers to a point where |E| 2 ≦10. s 1 illustrates a multilayer thin film having a dielectric layer 4 with a total thickness "D", incremental thickness "d", and refractive index "n" on a substrate layer 2 with a thickness "D". The substrate layer 2 can be the core layer or a reflective core layer of the multilayer thin film. Incident light strikes the outer surface 5 of the dielectric layer 4 at an angle θ with respect to a line 6 that is normal to the outer surface 5, and is reflected from the outer surface 5 at the same angle θ. The incident light penetrates the outer surface 5 and enters the dielectric layer 4 at an angle θ with respect to the line 6. F and the surface 3 of the base layer 2 is s In the case of a single dielectric layer, θ s =θ F The energy / electric field (E) can be expressed as E(z) when z=d. From Maxwell's equations, the electric field is, for s-polarized light,

number

number

[0049] It should be understood that the variation of the electric field along the z-direction of the dielectric layer 4 can be estimated by calculation of the unknown parameters u(z) and v(z), where:

number

number

number

number

number

number

number

[0050]

number

[0051] This allows for solving for the thickness "d" (i.e., the position or location within the dielectric layer where the electric field is zero). It should be understood that thickness "d" can be the thickness of the dielectric layer 120 extending over the reflective core layer 110 that provides a zero or near-zero electric field at the interface between the dielectric layer 120 and the metal absorbing layer 130. It should also be understood that thickness "d" can be the thickness of the dielectric outer layer 140 that extends over the metal absorbing layer 130 that provides a zero or near-zero electric field at the interface between the dielectric outer layer and the metal absorbing layer 130, depending on the thickness "d" where the electric field is zero or near-zero.

[0052] In embodiments, the at least one metal absorption layer 130 can have a thickness of 5 nm to 20 nm, such as 8 nm to 20 nm, 10 nm to 20 nm, 12 nm to 20 nm, 15 nm to 20 nm, 18 nm to 20 nm, 5 nm to 18 nm, 8 nm to 18 nm, 10 nm to 18 nm, 12 nm to 18 nm, 15 nm to 18 nm, 5 nm to 15 nm, 8 nm to 15 nm, 10 nm to 15 nm, 12 nm to 15 nm, 5 nm to 12 nm, 8 nm to 12 nm, 10 nm to 12 nm, 5 nm to 10 nm, 8 nm to 10 nm, or 5 nm to 8 nm, etc. In embodiments, the metal absorption layer 130 can be made of a material selected from at least W, Cr, Ge, Ni, stainless steel, Pd, Ti, Si, V, TiN, Co, Mo, Nb, ferric oxide, or a combination thereof. In one or more embodiments, the metal absorber layer 130 is, in embodiments, comprised of W. In embodiments, ALD is used to deposit the metal absorber layer 130 because ALD allows for uniform deposition of material at a desired thickness. Other deposition methods have difficulty depositing uniform layers at thicknesses of 20 nm or less.

[0053] In embodiments, the at least one dielectric outer layer 140 can have a thickness of greater than 0.1 quarter wavelengths (QW) to 4.0 QW, for example, 0.5 QW to 4.0 QW, 1.0 QW to 4.0 QW, 1.5 QW to 4.0 QW, 2.0 QW to 4.0 QW, 2.5 QW to 4.0 QW, 3.0 QW to 4.0 QW, or 3.5 QW to 4.0 QW, where the control wavelength is determined by the target wavelength at peak reflectance within the visible wavelengths. In embodiments, the at least one dielectric outer layer 140 can have a thickness of greater than 0.1 QW and less than 3.5 QW, e.g., greater than 0.1 QW and less than 3.0 QW, greater than 0.1 QW and less than 2.5 QW, greater than 0.1 QW and less than 2.0 QW, greater than 0.1 QW and less than 1.5 QW, greater than 0.1 QW and less than 1.0 QW, or greater than 0.1 QW and less than 0.5 QW. In some embodiments, the at least one dielectric outer layer 140 can have a thickness of 0.5 QW to 3.5 QW, e.g., 1.0 QW to 3.0 QW or 1.5 QW to 2.5 QW. In embodiments, the target wavelength can be about 1050 nm. The outer dielectric layer can be made from a dielectric material having a refractive index greater than 1.6, such as ZnS and TiO, or a combination thereof. In embodiments, the outer layer can be deposited by CVD or ALD.

[0054] In embodiments, the dielectric outer layer 140 can have a thickness of 5 to 500 nm, such as 50 nm to 500 nm, 100 nm to 500 nm, 150 nm to 500 nm, 200 nm to 500 nm, 250 nm to 500 nm, 300 nm to 500 nm, 350 nm to 500 nm, 400 nm to 500 nm, or 450 nm to 500 nm. In some embodiments, the at least one dielectric layer 120 can have a thickness of 5 nm to 450 nm, such as 5 nm to 400 nm, 5 nm to 350 nm, 5 nm to 300 nm, 5 nm to 250 nm, 5 nm to 200 nm, 5 nm to 150 nm, 5 nm to 100 nm, or 5 nm to 50 nm. In embodiments, the dielectric outer layer can have a thickness of 50 nm to 450 nm, such as 100 nm to 400 nm, 150 nm to 350 nm, or 200 nm to 300 nm.

[0055] The embodiments of the multilayer thin film 100 described above have a hue shift in the Lab color space when viewed at an angle between 0° and 45° of less than 30°, such as less than 25°, less than 20°, less than 15°, or less than 10°.

[0056] In one or more embodiments, the multilayer thin film 100 includes a reflective core layer 110 made of Al, a dielectric layer 120 made of TiO deposited by ALD or CVD and extending over the reflective core layer 110, a metal absorption layer 130 made of W deposited by ALD and extending over the dielectric layer 120, and a dielectric outer layer 140 made of TiO deposited by ALD or CVD and extending over the metal absorption layer 130.

[0057] In one or more embodiments, the multilayer thin film 100 includes a reflective core layer 110 made of Al, a dielectric layer 120 made of TiO deposited by ALD or CVD and extending over the reflective core layer 110, a metal absorption layer 130 made of W deposited by ALD and extending over the dielectric layer 120, and a dielectric outer layer 140 made of ZnS deposited by ALD or CVD and extending over the metal absorption layer 130.

[0058] 1B , a multilayer thin film 100 that reflects omnidirectionally high chroma structural colors according to an embodiment is shown. The multilayer thin film 100 includes a reflective core layer 110, a protective layer 150 encapsulating the reflective core layer 110, a dielectric layer 120 extending over at least a portion of the protective layer 150, a barrier layer 160 extending over the dielectric layer, a metal absorbing layer 130 extending over the barrier layer 160, and a dielectric outer layer 140 extending over at least one of the metal absorbing layers 130. In an embodiment, the "outer layer" has a free outer surface (i.e., an outer surface that is not in contact with an absorbing layer or with another dielectric layer that is not part of the protective coating). It should be understood that in embodiments, two dielectric absorbing layers 120, two metal absorbing layers 130, and two dielectric outer layers 140 can be disposed on either side of the reflective core layer 110, such that the reflective core layer 110 is a core layer encapsulated by a protective layer 150 and sandwiched between a pair of dielectric absorbing layers 120, a pair of metal absorbing layers 130, and a pair of dielectric outer layers 140. Such a multilayer film having a reflective core layer 110 encapsulated by a protective layer 150 and sandwiched between a pair of dielectric absorbing layers 120, a pair of metal absorbing layers 130, and a pair of dielectric outer layers can be referred to as a nine-layer multilayer thin film.

[0059] In an embodiment, the reflective core layer 110 has a thickness of 50 nm to 500 nm, for example, 100 nm to 500 nm, 150 nm to 500 nm, 200 nm to 500 nm, 250 nm to 500 nm, 300 nm to 500 nm, 350 nm to 500 nm, 400 nm to 500 nm, 450 nm to 500 nm, 50 nm to 450 nm, for example, 100 nm to 450 nm, 150 nm to 450 nm, 200 nm to 450 nm, 250 nm to 450 nm, 300 nm to 450 nm, 350 nm to 450 nm, 400 nm to 450 nm, 50 nm to 400 nm, for example, 100 nm to 400 nm, 150 nm to 400 nm, 200 nm to 400 nm, 250 nm to 400 nm, 300 The thickness may be, for example, 100 nm to 350 nm, 150 nm to 350 nm, 200 nm to 350 nm, 250 nm to 350 nm, 300 nm to 350 nm, 50 nm to 300 nm, for example, 100 nm to 300 nm, 150 nm to 300 nm, 200 nm to 300 nm, 250 nm to 300 nm, 50 nm to 250 nm, for example, 100 nm to 250 nm, 150 nm to 250 nm, 200 nm to 250 nm, 50 nm to 200 nm, for example, 100 nm to 200 nm, 150 nm to 200 nm, 50 nm to 150 nm, for example, 100 nm to 150 nm or 50 nm to 100 nm.

[0060] In embodiments, the reflective core layer 110 may be made from a "grey metal" material, such as at least one of Al, Ag, Pt, Sn, etc., or a "colorful metal" material, such as at least one of Au, Cu, brass, bronze, TiN, Cr, etc., or a combination thereof.

[0061] In an embodiment, the at least one protective layer 150 has a thickness of 2 nm to 70 nm, for example, 5 nm to 70 nm, 10 nm to 70 nm, 20 nm to 70 nm, 30 nm to 70 nm, 40 nm to 70 nm, 50 nm to 70 nm, 60 nm to 70 nm, 2 nm to 60 nm, 5 nm to 60 nm, 10 nm to 60 nm, 20 nm to 60 nm, 30 nm to 60 nm, 40 nm to 60 nm, 50 nm to 60 nm, 2 nm to 50 nm, 5 nm to 50 nm, 1 The protective layer 150 can have a thickness of 0 nm to 50 nm, 20 nm to 50 nm, 30 nm to 50 nm, 40 nm to 50 nm, 2 nm to 40 nm, 5 nm to 40 nm, 10 nm to 40 nm, 20 nm to 40 nm, 30 nm to 40 nm, 2 nm to 30 nm, 5 nm to 30 nm, 10 nm to 30 nm, 20 nm to 30 nm, 2 nm to 20 nm, 5 nm to 20 nm, 10 nm to 20 nm, 2 nm to 10 nm, 5 nm to 10 nm, or 2 nm to 5 nm, etc. In embodiments, the protective layer can be made of SiO2, SnO2, Al2O3, or combinations thereof. In embodiments, the protective layer 150 can be deposited over the reflective core layer 110 by a wet chemical deposition method, such as a sol-gel deposition method.

[0062] Without being bound by any particular theory, it is believed that protective layer 150 is advantageous in embodiments in which dielectric layer 120 extends over reflective core layer 110 because the process for depositing dielectric layer 120 can damage reflective core layer 110, such as by oxidizing or deforming it. Protective layer 150 protects reflective core layer 110 from damage caused by, for example, the highly basic / acidic conditions of wet-chemical deposition. However, the addition of protective layer 150 can alter the reflectivity of reflective core layer 110. A thin protective layer 150, having the thickness described above, is desirable because a thick protective layer can have an undesirable effect on the reflectivity of the multilayer thin film. In embodiments, the change in reflectivity caused by protective layer 150 can be compensated for by adding a corresponding metal absorbing layer 130 and an outer layer made of a dielectric material.

[0063] According to embodiments, the at least one dielectric layer 120 can have a thickness of 10 to 150 nm, such as 25 nm to 150 nm, 50 nm to 150 nm, 75 nm to 150 nm, 100 nm to 150 nm, 125 nm to 150 nm, 10 nm to 125 nm, 25 nm to 125 nm, 50 nm to 125 nm, 75 nm to 125 nm, 100 nm to 125 nm, 10 nm to 100 nm, 25 nm to 100 nm, 50 nm to 100 nm, 75 nm to 100 nm, 10 nm to 75 nm, 25 nm to 75 nm, 50 to 75 nm, 10 nm to 50 nm, 25 nm to 50 nm, or 10 to 25 nm.

[0064] At least one dielectric layer 120 is TiO and may be deposited over the reflective core layer 110 by chemical vapor deposition (CVD), atomic layer deposition (ALD), or wet chemical processes. As noted above, the TiO dielectric layer is, in embodiments, amorphous phase TiO.

[0065] In embodiments including at least one barrier layer 160, the at least one barrier layer 160 can be made, for example, from Al2O3 and SiO2 and have a thickness of 1 nm to 15 nm, e.g., 1 nm to 12 nm, 1 nm to 10 nm, 1 nm to 8 nm, 1 nm to 6 nm, 1 nm to 4 nm, 1 nm to 2 nm, 2 nm to 15 nm, 2 nm to 12 nm, 2 nm to 10 nm, 2 nm to 8 nm, 2 nm to 6 nm, 2 nm to 4 nm, 4 nm to 15 nm, 4 nm to 12 nm, 4 nm to 10 nm, 4 nm to 8 nm, 4 nm to 6 nm, 6 nm to 15 nm, 6 nm to 12 nm, 6 nm to 10 nm, 6 nm to 8 nm, 8 nm to 15 nm, 8 nm to 12 nm, 8 nm to 10 nm, 10 nm to 15 nm, 10 nm to 12 nm, or 12 nm to 15 nm. At least one barrier layer 160 is deposited by ALD, according to one or more embodiments. In an embodiment, at least one barrier layer 160 is SiO2 and is deposited by a wet chemical process. In an embodiment, at least one barrier layer 160 is Al2O3 and is deposited by CVD.

[0066] In embodiments, the at least one metal absorption layer 130 may be positioned such that the electric field of the target wavelength to be reflected is zero or nearly zero, as described above. In embodiments, the at least one metal absorption layer 130 has a thickness of 5 nm to 20 nm, such as 8 nm to 20 nm, 10 nm to 20 nm, 12 nm to 20 nm, 15 nm to 20 nm, 18 nm to 20 nm, 5 nm to 18 nm, 8 nm to 18 nm, 10 nm to 18 nm, 10 nm to 18 nm, 12 nm to 18 nm, 15 nm to 18 nm, 10 nm to 18 nm, 12 nm to 18 nm, 15 nm to 18 nm, 5 nm to 15 nm, 8 nm to 15 nm, 10 nm to 15 nm, 12 nm to 15 nm, 5 nm to 12 nm, 8 nm to 12 nm, 10 nm to 12 nm, 5 nm to 10 nm, 8 nm to 10 nm, or 5 nm to 8 nm. In embodiments, the metal absorber layer 130 can be made from a material selected from at least W, Cr, Ge, Ni, stainless steel, Pd, Ti, Si, V, TiN, Co, Mo, Nb, ferric oxide, or combinations thereof. In one or more embodiments, the metal absorber layer 130 is composed of W. In embodiments, ALD is used to deposit the metal absorber layer 130 because it allows for uniform deposition of materials at a desired thickness. Other deposition methods have difficulty depositing uniform layers at thicknesses of 20 nm or less.

[0067] In embodiments, the at least one dielectric outer layer 140 can have a thickness of greater than 0.1 quarter wavelengths (QW) to 4.0 QW, for example, 0.5 QW to 4.0 QW, 1.0 QW to 4.0 QW, 1.5 QW to 4.0 QW, 2.0 QW to 4.0 QW, 2.5 QW to 4.0 QW, 3.0 QW to 4.0 QW, or 3.5 QW to 4.0 QW, where the control wavelength is determined by the target wavelength at peak reflectance within the visible wavelengths. In embodiments, the at least one dielectric outer layer 140 can have a thickness of greater than 0.1 QW and less than 3.5 QW, e.g., greater than 0.1 QW and less than 3.0 QW, greater than 0.1 QW and less than 2.5 QW, greater than 0.1 QW and less than 2.0 QW, greater than 0.1 QW and less than 1.5 QW, greater than 0.1 QW and less than 1.0 QW, or greater than 0.1 QW and less than 0.5 QW. In some embodiments, the at least one dielectric outer layer 140 can have a thickness of 0.5 QW to 3.5 QW, e.g., 1.0 QW to 3.0 QW or 1.5 QW to 2.5 QW. In embodiments, the target wavelength can be about 1050 nm. The outer dielectric layer can be made from a dielectric material having a refractive index greater than 1.6, such as ZnS and TiO, or a combination thereof. In embodiments, the outer layer can be deposited by CVD or ALD.

[0068] In embodiments, the dielectric outer layer 140 can have a thickness of 5 to 500 nm, such as 50 nm to 500 nm, 100 nm to 500 nm, 150 nm to 500 nm, 200 nm to 500 nm, 250 nm to 500 nm, 300 nm to 500 nm, 350 nm to 500 nm, 400 nm to 500 nm, or 450 nm to 500 nm. In some embodiments, the at least one dielectric layer 120 can have a thickness of 5 nm to 450 nm, 5 nm to 400 nm, 5 nm to 350 nm, 5 nm to 300 nm, 5 nm to 250 nm, 5 nm to 200 nm, 5 nm to 150 nm, 5 nm to 100 nm, or 5 nm to 50 nm. In embodiments, the dielectric outer layer can have a thickness of from 50 nm to 450 nm, for example, from 100 nm to 400 nm, from 150 nm to 350 nm, or from 200 nm to 300 nm.

[0069] The embodiments of the multilayer thin film 100 described above have a hue shift of less than 30° in the Lab color space when viewed at an angle between 0° and 45°, such as less than 25°, less than 20°, less than 15°, or less than 10°.

[0070] In one or more embodiments, the multilayer thin film 100 includes a reflective core layer 110 made of Al, a protective layer 150 made of SiO deposited by a wet chemical process and encapsulating the reflective core layer 110, a dielectric layer 120 made of TiO deposited by CVD, ALD, or a wet chemical process and extending over at least a portion of the protective layer 150, a metal absorption layer 130 made of W deposited by ALD and extending over the dielectric layer 120, and a dielectric outer layer 140 made of TiO deposited by CVD or ALD and extending over the metal absorption layer 130.

[0071] In one or more embodiments, the multilayer thin film 100 includes a reflective core layer 110 made of Al, a protective layer 150 made of SiO deposited by a wet chemical process and encapsulating the reflective core layer 110, a dielectric layer 120 made of TiO deposited by CVD or ALD and extending over at least a portion of the protective layer 150, a metal absorption layer 130 made of W deposited by ALD and extending over the dielectric layer 120, and a dielectric outer layer 140 made of ZnS deposited by CVD or ALD and extending over the metal absorption layer 130.

[0072] In one or more embodiments, the multilayer thin film 100 includes a reflective core layer 110 made of Al, a protective layer 150 made of SiO deposited by a wet chemical process and encapsulating the reflective core layer 110, a dielectric layer 120 made of TiO deposited by CVD, ALD, or a wet chemical process and extending over at least a portion of the protective layer 150, a barrier layer 160 made of AlO deposited by ALD and extending over the dielectric layer 120, a metal absorption layer 130 made of W deposited by ALD and extending over the barrier layer 160, and a dielectric outer layer 140 made of TiO deposited by CVD or ALD and extending over the metal absorption layer 130.

[0073] In one or more embodiments, the multilayer thin film 100 includes a reflective core layer 110 made of Al; a protective layer 150 made of SiO deposited by a wet chemical process and encapsulating the reflective core layer 110; a dielectric layer 120 made of TiO deposited by CVD, ALD, or a wet chemical process and extending over at least a portion of the protective layer 150; a barrier layer 160 made of AlO deposited by ALD and extending over the dielectric layer 120; a metal absorption layer 130 made of W deposited by ALD and extending over the barrier layer 160; and a dielectric outer layer 140 made of ZnS deposited by CVD or ALD and extending over the metal absorption layer 130.

[0074] The multilayer thin films in the embodiments disclosed herein can be used as pigments (e.g., paint pigments for paints used to paint objects) or as continuous thin films applied to objects. When used as pigments, at least one of a paint binder and a filler can be used and mixed with the pigment to provide a paint exhibiting an omnidirectional, high-chroma red structural color. Additionally, other additives may be added to the multilayer thin film to aid in the compatibility of the multilayer thin film in a paint system. Exemplary compatibility-enhancing additives include silane surface treatments that coat the exterior of the multilayer thin film and improve the compatibility of the multilayer thin film in a paint system. Such a paint system or film can be used on any article, including automobiles.

[0075] It should be noted that the terms "substantially" and "about" may be used in this disclosure to express the inherent degree of uncertainty that may result from any quantitative comparison, value, measurement, or other representation. These terms are also used in this disclosure to express the extent to which a quantitative representation may vary from the stated basis without resulting in a change in the basic functionality of the subject matter at issue. [Example]

[0076] The embodiments will be further clarified by the following examples. Example 1

[0077] Five simulations were performed using amorphous-phase TiO dielectric layers with refractive indices ranging from 2.2 to 2.3. The thickness of the TiO dielectric layer was varied throughout the simulations. Each simulation included an aluminum core, an amorphous-phase TiO dielectric layer deposited on the aluminum core, and a 10 nm thick tungsten absorber layer deposited on the amorphous-phase TiO.

[0078] Figure 9A shows the simulated reflectance curves for an amorphous TiO layer with a thickness of 30 nm. The target reflectance curve is the thicker curve with a single spike near a wavelength of 400 nm, while the simulated curve is the thinner curve. As shown in Figure 9A, the simulated reflectance curve does not match the target reflectance curve.

[0079] Figure 9B shows the simulated reflectance curves when the amorphous-phase TiO layer is 50 nm thick. The target reflectance curve is the thicker curve with a single spike near a wavelength of 400 nm, while the simulated curve is the thinner curve. As shown in Figure 9B, the simulated reflectance curve is close to, but does not match, the target reflectance curve.

[0080] Figure 9C shows the simulated reflectance curve when the amorphous phase TiO layer has a thickness of 70 nm. The target reflectance curve is the thicker curve with a single spike near a wavelength of 400 nm, and the simulated curve is the thinner curve. As shown in Figure 9C, the simulated reflectance curve closely matches the target reflectance curve.

[0081] Figure 9D shows the simulated reflectance curve when the amorphous-phase TiO layer is 90 nm thick. The target reflectance curve is the thicker curve with a single spike near 400 nm, while the simulated curve is the thinner curve. As shown in Figure 9D, the simulated reflectance curve is broader than the target reflectance curve.

[0082] Figure 9E shows a simulated reflectance curve for a 70 nm thick amorphous TiO layer deposited on a 10 nm thick tungsten absorber layer. The target reflectance curve is the thicker curve with a single spike near 400 nm, while the simulated curve is the thinner curve. As shown in Figure 9E, the simulated reflectance curve closely matches the target reflectance curve. Example 2

[0083] Six simulations were performed using amorphous-phase TiO dielectric layers with refractive indices ranging from 1.8 to 2.0. The thickness of the TiO dielectric layer was varied throughout the simulations. Each simulation included an aluminum core, an amorphous-phase TiO dielectric layer deposited on the aluminum core, and a 10 nm thick tungsten absorber layer deposited on the amorphous-phase TiO.

[0084] Figure 10A shows a simulated reflectance curve for an amorphous TiO layer with a thickness of 30 nm. The target reflectance curve is the thicker curve with a single spike near a wavelength of 400 nm, while the simulated curve is the thinner curve. As shown in Figure 10A, the simulated reflectance curve does not match the target reflectance curve.

[0085] Figure 10B shows the simulated reflectance curve when the amorphous phase TiO layer is 50 nm thick. The target reflectance curve is the thicker curve with a single spike near a wavelength of 400 nm, while the simulated curve is the thinner curve. As shown in Figure 10B, the simulated reflectance curve does not match the target reflectance curve.

[0086] Figure 10C shows the simulated reflectance curves for an amorphous TiO layer with a thickness of 70 nm. The target reflectance curve is the thicker curve with a single spike near a wavelength of 400 nm, while the simulated curve is the thinner curve. As shown in Figure 10C, the simulated reflectance curve is close to, but does not match, the target reflectance curve.

[0087] Figure 10D shows the simulated reflectance curve when the amorphous-phase TiO layer is 90 nm thick. The target reflectance curve is the thicker curve with a single spike near 400 nm, while the simulated curve is the thinner curve. As shown in Figure 10D, the simulated reflectance curve matches the target reflectance curve.

[0088] Figure 10E shows a simulated reflectance curve for a 70 nm thick amorphous TiO layer deposited on a 10 nm thick tungsten absorber layer. The target reflectance curve is the thicker curve with a single spike near 400 nm, while the simulated curve is the thinner curve. As shown in Figure 10E, the simulated reflectance curve is close to, but does not match, the target reflectance curve.

[0089] Figure 10F shows a simulated reflectance curve for a 90 nm thick amorphous TiO layer, with an additional 90 nm thick amorphous TiO layer deposited on a 10 nm thick tungsten absorber layer. The target reflectance curve is the thicker curve with a single spike near 400 nm, while the simulated curve is the thinner curve. As shown in Figure 10F, the simulated reflectance curve closely matches the target reflectance curve.

[0090] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, this specification is intended to cover modifications and variations of the various embodiments described herein, provided such modifications and variations come within the scope of the appended claims and their equivalents.

Claims

1. A multilayer thin film that reflects omnidirectional structural color, a reflective core layer; an amorphous phase TiO extending across the reflective core layer; ２ a dielectric layer; The amorphous phase TiO ２ a metal absorbing layer extending over the dielectric layer; a dielectric outer layer extending over the metal absorbing layer; Including, 1. A multilayer thin film, wherein the multilayer thin film, when exposed to broadband electromagnetic radiation, reflects a single narrow band of visible light, the single narrow band of visible light comprising a color shift of the single narrow band of visible light, measured in Lab color space, of less than 30° when the multilayer thin film is exposed to broadband electromagnetic radiation and observed from an angle of 0° to 45° relative to a direction normal to an outer surface of the multilayer thin film.

2. 10. The multilayer thin film of claim 1, wherein the reflective core layer is formed from Al, Ag, Pt, Sn, Au, Cu, brass, bronze, TiN, Cr, or a combination thereof.

3. 10. The multilayer thin film of claim 1, wherein the reflective core layer has a thickness of 50 nm to 500 nm.

4. The amorphous phase TiO ２ The multilayer thin film of claim 1, wherein the dielectric layer has a thickness of 10 nm to 150 nm.

5. 10. The multilayer thin film of claim 1, wherein the metal absorbing layer is formed from W, Cr, Ge, Ni, stainless steel, Pd, Ti, Si, V, TiN, Co, Mo, Nb, ferric oxide, or a combination thereof.

6. The multilayer thin film of claim 1, wherein the metal absorbing layer has a thickness of 5 nm to 20 nm.

7. The dielectric outer layer is made of ZnS, TiO ２ 10. The multilayer thin film of claim 1 formed from:

8. 10. The multilayer thin film of claim 1, wherein the dielectric outer layer has a thickness of greater than 0.1 quarter wavelengths (QW) to less than or equal to 4.0 QW, where the control wavelength is determined by a target wavelength at peak reflectivity within visible wavelengths.

9. The multilayer thin film of claim 1, wherein the dielectric outer layer has a thickness of 5 nm to 500 nm.

10. the reflective core layer is formed from Al; the metal absorption layer is formed from W; The dielectric outer layer is made of ZnS or TiO ２ formed from The multilayer thin film of claim 1 .

11. A multilayer thin film that reflects omnidirectional structural color, a reflective core layer; a protective layer encapsulating the reflective core layer; an amorphous phase TiO extending across at least a portion of said protective layer; ２ a dielectric layer; and the amorphous phase TiO ２ a barrier layer extending over the dielectric layer; a metal absorbing layer extending over the barrier layer; a dielectric outer layer extending over the metal absorbing layer; wherein the multilayer film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, the single narrow band of visible light comprising a color shift of the single narrow band of visible light, measured in Lab color space, of less than 30° when the multilayer film is exposed to broadband electromagnetic radiation and observed from an angle between 0° and 45° relative to a direction normal to an outer surface of the multilayer film.

12. 12. The multilayer thin film of claim 11, wherein the reflective core layer is formed from Al, Ag, Pt, Sn, Au, Cu, brass, bronze, TiN, Cr, or a combination thereof.

13. The multilayer thin film of claim 11, wherein the reflective core layer has a thickness of 50 nm to 500 nm.

14. The protective layer is made of Si, SnO ２ , Al ２ O ３ 12. The multilayer thin film of claim 11, formed from:

15. The multilayer thin film of claim 11, wherein the protective layer has a thickness of 2 nm to 70 nm.

16. The amorphous phase TiO ２ The multilayer thin film of claim 11, wherein the dielectric layer has a thickness of 10 nm to 150 nm.

17. 12. The multilayer thin film of claim 11, wherein the metal absorbing layer is formed from W, Cr, Ge, Ni, stainless steel, Pd, Ti, Si, V, TiN, Co, Mo, Nb, ferric oxide, amorphous silicon, or a combination thereof.

18. The multilayer thin film of claim 11, wherein the metal absorbing layer has a thickness of 5 nm to 20 nm.

19. The dielectric outer layer is made of ZnS, TiO ２ 12. The multilayer film of claim 11 formed from:

20. 12. The multilayer thin film of claim 11, wherein the dielectric outer layer has a thickness of greater than 0.1 quarter wavelengths (QW) to less than or equal to 4.0 QW, where the control wavelength is determined by a target wavelength at peak reflectivity within visible wavelengths.

21. The multilayer thin film of claim 11, wherein the dielectric outer layer has a thickness of 5 nm to 500 nm.

22. The barrier layer is Al ２ O ３ The multilayer thin film of claim 11 formed from

23. The multilayer thin film of claim 11, wherein the barrier layer has a thickness of 1 nm to 15 nm.

24. the reflective core layer is formed from Al; The protective layer is made of SiO ２ is formed from the metal absorption layer is formed from W; The barrier layer is Al ２ O ３ is formed from The dielectric outer layer is ZnS or TiO ２ formed from The multilayer thin film of claim 11.

25. 10. A method for forming the multilayer thin film of claim 1, comprising: The amorphous phase TiO is deposited on the reflective core layer by CVD or ALD. ２ depositing a dielectric layer; The amorphous phase TiO ２ depositing the metal absorbing layer on a dielectric layer; and depositing the dielectric outer layer on the metal absorbing layer by CVD or ALD.

26. 12. A method of forming the multilayer thin film of claim 11, comprising: depositing the protective layer on the reflective core layer by a wet chemical process; The amorphous phase TiO is deposited on the protective layer by CVD, ALD or wet chemical process. ２ depositing a dielectric layer; The amorphous phase TiO ２ depositing the barrier layer on a dielectric layer; depositing the metal absorber layer on the barrier layer by ALD; and depositing the dielectric outer layer on the metal absorbing layer by CVD or ALD.

27. A coating system comprising a binder and the multilayer film of claim 1.

28. 28. An automobile equipped with the coating system of claim 27.

29. A coating system comprising a binder and the multilayer film of claim 11.

30. 30. An automobile comprising the coating system of claim 29.

Images