Structured color display devices and their manufacturing methods

Abstract

This invention provides a method, apparatus, and device for fabricating a structural color display device. The method includes fabricating multiple nanopillar array units on a test substrate to obtain a processing parameter table corresponding to the height, linewidth, and period of the nanopillars and the display colors; determining the structural color corresponding to each pixel of a target image, and thereby determining the processing amount of the nanopillar array units corresponding to each pixel based on the processing parameter table; and fabricating a metasurface layer on the target substrate to create a structural color display device for displaying the target image. This method expands the pixel color richness and control precision through multidimensional control of the height, linewidth, and period of the nanopillar array units, while significantly reducing the pixel area.

Description

Technical Field

[0001] This application relates to the fields of micro-nano fabrication and micro-nano display, specifically to a structural color display device and its fabrication method. Background Technology

[0002] Micro-nano fabrication technology refers to the optimized design, processing, assembly, system integration, and application of components and systems at the sub-millimeter, micrometer, and nanometer scales. Structural color, as the color response resulting from the structural configuration of an object at the micro-nano scale, possesses advantages over chemical colors, including resistance to fading, vivid colors, and smaller pixel sizes, thus showing great promise for applications in micro-nano integrable imaging systems. The color rendering capability of structural color display devices stems from the metasurface structures constructed at the microscale. The structural units of these metasurface structures possess strong subwavelength amplitude modulation capabilities, enabling each unit to reflect specific wavelengths of visible or invisible light onto the observation surface. Structural colors naturally offer higher resolution and longer shelf life, providing a novel option for color display devices, especially those suitable for micro- or meso-scale applications. Therefore, expanding the application range of structural color devices and improving their display effects is of significant application value. However, the difficulties of micro-nano fabrication make it challenging to fabricate structural color display devices over large areas with high precision. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, a first aspect of this application provides a method for fabricating a structural color display device, wherein the structural color display device includes a substrate layer and a plurality of nanopillar array units located thereon, the nanopillar array units having a plurality of nanopillars extending above the substrate layer; the method includes:

[0004] The structural color corresponding to each pixel of the target image is determined, and the processing amount of the nanopillar array unit corresponding to each pixel is determined according to the processing parameter table, wherein the processing parameter table represents the relationship between the structural color displayed by the nanopillar array unit and the corresponding processing amount, and the processing amount includes the height, linewidth and period of the nanopillar, wherein the height represents the height of the nanopillar above the substrate layer, the linewidth represents the cross-sectional dimension of the nanopillar along the substrate layer, and the period represents the distance from the center to the center of two adjacent nanopillars;

[0005] Based on the amount of processing of the nanopillar array units corresponding to each pixel, a metasurface layer is fabricated on the target substrate to create the structural color display device capable of displaying the target image, wherein the metasurface layer is composed of all the nanopillar array units corresponding to the target image.

[0006] Preferably, the method for manufacturing the structural color display device further includes first fabricating a light-reflecting layer on the target substrate layer, and then fabricating the metasurface layer on the light-reflecting layer, wherein the light-reflecting layer has a reflective effect on light transmitted from the metasurface layer.

[0007] Preferably, the method for fabricating the structural color display device, wherein fabricating multiple nanopillar array units with different processing amounts on a test substrate layer includes:

[0008] The structural color brightness of the nanopillar array unit can be changed at least by adjusting the height of the nanopillars;

[0009] The structural color hue of the nanopillar array unit can be changed at least by adjusting the period of the nanopillars;

[0010] The structural color saturation of the nanopillar array unit can be changed at least by adjusting the linewidth of the nanopillars.

[0011] A second aspect of this application provides a structural color display device, comprising a substrate layer and a metasurface layer disposed thereon, wherein,

[0012] The metasurface layer comprises a plurality of nanopillar array units, each nanopillar array unit having a plurality of nanopillars forming a rectangular array; the nanopillar array units are used to receive and modulate incident light, thereby causing the emitted light to have a specific amplitude and frequency and display a specific structural color; and wherein

[0013] The nanopillar array unit is configured to determine the specific amplitude and frequency of the emitted light based on the height, linewidth, and period of the nanopillars therein, wherein the linewidth represents the cross-sectional dimension of the nanopillar, and the period represents the distance between two adjacent nanopillars.

[0014] Preferably, the structural color display device further includes a light-reflecting layer disposed between the substrate layer and the metasurface layer, wherein the light-reflecting layer reflects light transmitted from the metasurface layer so that the transmitted light passes a second time through the nanopillar array units of the metasurface layer and is modulated therein to increase the proportion of emitted light with the specific amplitude and frequency.

[0015] Preferably, in the structural color display device, the substrate layer is configured to provide support for the metasurface layer, and the substrate layer is one of fused silica, sapphire wafer, silicon wafer, gallium arsenide wafer, a SiNx thin film material window supported by a grid, or a SiO2 thin film material window; and

[0016] The thickness of the substrate layer can be configured to be between 100 nm and 1 μm, between 1 μm and 500 μm, or between 500 μm and 1 mm.

[0017] Preferably, in the structural color display device, the size of the nanopillar array unit can be configured to be between 1μm and 3μm, so that the resolution of the structural color display device is between 6.4×108dpi and 7.2×107dpi.

[0018] Preferably, in the structural color display device, the material constituting the nanopillars includes at least one selected from SiO2, SiNx, TiO2, gold, and aluminum; and

[0019] The height of the nanopillar is configured to be between 0 and 1 μm, the linewidth of the nanopillar is configured to be between 50 nm and 500 nm, the period of the nanopillar is configured to be between 100 nm and 3 μm, and the cross-section of the nanopillar is one of a circle, an ellipse, or a polygon.

[0020] Preferably, in the structural color display device, the material constituting the light reflective layer is at least one of gold, silver and aluminum to have high light reflectivity, and its thickness is configured to be between 50 nm and 1 μm.

[0021] A third aspect of this application provides an apparatus for fabricating a structural color display device according to the method described in the first aspect of this application, comprising a control unit and a processing unit, wherein...

[0022] The control unit stores the predetermined processing parameter table.

[0023] The control unit is configured to determine the structural color corresponding to each pixel of the target image, thereby determining the processing amount of the nanopillar array unit corresponding to each pixel according to the processing parameter table;

[0024] The control unit is configured to control the processing unit to fabricate a metasurface layer on a target substrate layer according to the amount of processing of the nanopillar array unit corresponding to each pixel, so as to fabricate the structural color display device for displaying the target image, wherein the metasurface layer is composed of all the nanopillar array units corresponding to the target image.

[0025] In this application, a multidimensional controllable structural color display device based on a height gradient metasurface can achieve arbitrary adjustment of pixel color through multidimensional control of structural height, planar size, and period. Compared with traditional structural color devices, this device greatly improves the freedom of color display through the degree of freedom in the height direction, thereby improving image display quality and showing broad application prospects in the field of micro-nano displays and optical encryption devices. Attached Figure Description

[0026] The embodiments of the present invention will be further described below with reference to the accompanying drawings, wherein:

[0027] Figure 1 and Figure 2 A top view and a side view of the structure of a structural color display device are shown as examples;

[0028] Figure 3 The illustration exemplarily shows the colors displayed by a series of sites corresponding to nanopillar array cells in an orthogonal coordinate system consisting of three variables: height, period, and linewidth in the nanopillar array cells, as measured experimentally.

[0029] Figure 4 The measured color point values ​​corresponding to the height, period, and linewidth of the nanopillar array unit represented in HSB space are shown.

[0030] Figure 5 An example of a color picture arranged on a structural color display device is provided;

[0031] Figure 6 It shows the Figure 5 A magnified SEM image of the metasurface microstructure near one pixel of the color image shown.

[0032] Figure 7 A side view of a nanopillar array cell displaying a specific color is given;

[0033] Figure 8 Several typical colors and the nanopillar array units that achieve these colors are shown. Detailed Implementation

[0034] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0035] The inventors recognized that introducing height gradients into the field of structural color display, and utilizing the synergistic modulation of the structure's height, planar dimensions (or linewidth), and period to achieve multidimensional control of image colors, presents entirely new possibilities for the realization of micro / nano-integrable color display devices. Therefore, they proposed a multidimensional controllable structural color display device based on a height-gradient metasurface, which contributes to the reduction in size and high-density integration of micro / nano display systems and optical encryption devices.

[0036] The first embodiment of this application provides a structural color display device, whose display mechanism is based on the specific structural color caused by the different wavelengths and intensities of reflected and absorbed light from a highly gradient metasurface structure. The structural color display device has a metasurface layer and a substrate layer, wherein the metasurface layer is disposed on the substrate layer. The substrate layer is a rigid support material of a certain thickness, serving as a support for the ultra-thin structural color display film. The metasurface layer of the structural color display device faces the outer surface of the observer. The metasurface layer is composed of multiple nanopillar array units on the substrate layer. Each nanopillar array unit can display a corresponding color according to a setting as a minimum pixel. Through interaction with incident light, the amplitude and frequency of the reflected light are modulated, thereby generating the structural color display function. The nanopillar array units are disposed on the outer surface of the metasurface layer of the structural color display device facing the observer. Each nanopillar array unit consists of a rectangular array of m×n nanopillars, where m and n are integers and can be equal or unequal.

[0037] Figure 1 and Figure 2 A top view and a side view of the structure of a structural color display device are shown as examples. For the sake of simplicity, Figure 1 and Figure 2 The illustrated structured color display device 100 has a 3×3 rectangular array of nanopillar array units. Each of the nine nanopillars 101 is shown as a square pillar with consistent size and spacing, and the nanopillars 101 are arranged on a substrate layer 102. Adjustable parameters in the configuration of this nanopillar array unit include: height, period, and linewidth; wherein, in the various embodiments of this application, the height is uniformly defined as the distance of the nanopillar from the substrate layer, such as... Figure 2 The height h is shown; the period represents the center-to-center spacing between every two adjacent nanopillars, such as... Figure 2 The period T shown; the linewidth represents the cross-sectional dimension of a single nanopillar along the substrate, for example... Figure 2 The base length *s* of the central column is used; however, in other embodiments where the nanopillars are shaped as cylinders, prisms, or elliptical cylinders, the linewidth can also represent the diameter or major axis / long side of the cross-section of a single column. Furthermore, additional adjustable parameters include the number of nanopillar array units *m* and *n*, and the spacing between two array units. However, considering that a nanopillar array unit can generally be considered a minimum pixel unit, to achieve a high pixel density, it is not advisable to arrange too many nanopillars in a single nanopillar array unit. Figure 1 and Figure 2 The structured color display device shown has only one nanopillar array unit, which is merely an example. Typically, a single nanopillar array unit on a structured color display device is used to display the color of one pixel, while a structured color display device used to display a complete image will contain dozens, tens of thousands, or millions or even more pixels depending on the requirements.

[0038] The inventors surprisingly discovered that by transforming the height, period, and linewidth of a nanopillar array unit in their respective dimensions, the hue, saturation, and brightness of the structural color corresponding to that unit can be changed accordingly within their respective domains. In other words, by combining and adjusting the height, period, and linewidth of the nanopillar array unit, these three color parameters can be simultaneously adjusted to traverse various points in the HSB color space (i.e., the color representation space composed of hue, saturation, and brightness). The inventors further verified this finding by analyzing a large amount of data on the height, period, and linewidth variables and their corresponding colors in further experiments.

[0039] Figure 3 The illustration exemplifies the colors displayed by a series of sites corresponding to nanopillar array cells in an orthogonal coordinate system consisting of three variables: height, period, and linewidth, as measured experimentally. Figure 3 The display richness basically covers the range of hue, saturation, and brightness values ​​for common colors. After determining the mapping relationship between this control variable and color, the inventors further discovered the following patterns: 1) Changes in the height of the nanopillar array unit significantly affect the brightness of the structural color of that unit, with the general trend being: the higher the height, the lower the brightness; in addition, changes in height also alter the hue and saturation of the structural color of that unit to some extent. 2) Controlling the period in the nanopillar array unit can effectively change the hue of the structural color of that unit, and also alters the brightness and saturation of the structural color of that unit to some extent. 3) Controlling the linewidth in the nanopillar array unit can effectively change the saturation of the structural color of that unit, and also alters the brightness and hue of the structural color of that unit to some extent.

[0040] Figure 4 The diagram shows the measured color point values ​​corresponding to the height, period, and linewidth of the nanopillar array cells represented in HSB space. Combined with... Figure 3 and Figure 4 It is evident that after accumulating a sufficient number of colors obtained from testing the aforementioned variables, any color in the HSB space can find a directly corresponding or closest nanopillar array unit height, period, and linewidth. Therefore, a lookup table can be used to generate a processing parameter table pixel-by-pixel from an image. This table marks the required height, period, and linewidth of the nanopillar array unit corresponding to the color value of each pixel. Subsequently, the control unit of the processing device can process a similar image onto the target surface according to the processing parameter table. Figure 2 The metasurface structure shown.

[0041] Figure 5An example of a color image arranged on a structured color display device is provided. The color of each pixel is displayed by structured light reflected from nanopillar array units with corresponding height, period, and linewidth. The pixel width is 1.5 μm, and the imaging resolution is 2.9 × 10⁻⁶. 8 dpi.

[0042] Figure 6 It shows the Figure 5 The image shown is a magnified SEM image of the metasurface microstructure near one of the pixels in the color picture. Figure 6 Multiple nanopillar array units with different configurations are shown, each configured to display different colors. It can be seen that the linewidth, height, and period of the nanopillar array unit corresponding to each pixel are different. Depending on the fabrication precision and practical requirements, the single pixel size can be arbitrarily selected between 1μm and 3μm, and correspondingly, the image resolution can be 6.4×10⁻⁶. 8 dpi-7.2×10 7 Choose any of the dpi options.

[0043] Since adjusting the height of the nanopillars does not increase the total area of ​​a single nanopillar array unit along the surface, the total area of ​​the smallest single pixel representing color can be controlled to a smaller value, thus significantly improving pixel density. Because the combined adjustment of height, period, and linewidth reveals a wider range of possible values ​​for hue, saturation, and brightness of the structural color, the configuration of the nanopillar array unit for the target pixel can be determined accurately and quickly.

[0044] The second embodiment of this application provides another example of a structured color display device. The structured color display device has a metasurface layer, a light-reflecting layer, and a substrate layer arranged sequentially downwards from the observation surface. The metasurface layer is composed of an array of nanopillar units with different height gradients. Through interaction with incident light, it achieves amplitude and frequency modulation of the reflected light, absorbing a portion of wavelengths with specific amplitudes and frequencies and reflecting other wavelengths with specific amplitudes and frequencies, thereby generating a color response on the observation surface and producing a structured color display function. Unlike the first embodiment, the structured color display device of this embodiment also includes a light-reflecting layer, which is a metal thin film with high reflectivity, used to reflect light incident from the observation surface and transmitted through the metasurface layer, reflecting it back into the metasurface and subjecting it to a second light modulation within the nanopillar array units. The substrate layer is a rigid support material with a certain thickness. The nanopillar array units are composed of nanopillars that rise and extend outwards from the surface of the light-reflecting layer (i.e., towards the observation direction of light incidence).

[0045] Figure 7 A side view of a nanopillar array cell displaying a specific color is given. Figure 7Only one nanopillar array unit 201 of the structural color display device 200 is shown; however, the structural color display device 200 may contain a large number of nanopillar array units, and the layer formed by these nanopillar array units is called a metasurface layer. This exemplary nanopillar array unit 201 is shaped as a 3×3 array of TiO2 nanopillar structures, with its linewidth s, height h, and period T defined consistent with the first embodiment, and the parameters being s = 200 nm, h = 800 nm, and T = 400 nm. The light-reflecting layer 204 is an aluminum film with a thickness of 100 nm; the substrate layer 206 is a fused silica sheet with a thickness of 500 μm, serving as support for the nanopillar array unit 201 and the reflective layer 204 on the metasurface layer.

[0046] Figure 8 Several typical colors and the nanopillar array units that achieve these colors are shown. Figure 8 The first image from the left shows a 3×3 array displaying the yellow structural color; the second image from the left shows a 3×4 array displaying the blue structural color; the third image from the left shows a 2×2 array displaying the green structural color; and the fourth image from the left shows a 4×4 array displaying the red structural color. The nanopillar array unit size (or single pixel size) is 1.5μm × 1.5μm.

[0047] Besides fused silica sheets, the substrate can be any material that provides rigid support for the metasurface layer and the light-reflecting layer, such as transparent materials like sapphire sheets, opaque materials like silicon wafers and gallium arsenide wafers, or SiN supported by a grid. x Thin film materials such as SiO2 can be used for windows. The substrate thickness can be any thickness above 100nm, such as 1μm-1000μm or 1mm-1000mm.

[0048] The structure of the nanopillar array unit is not intended to be limited to square pillars with a linewidth of 200 nm, but can be pillars with regular cross-sections (such as circles, triangles, rectangles, ellipses, regular polygons, etc.). Its radius or side length can be selected between 50 nm and 500 nm according to processing requirements, and its height can be arbitrarily selected between 0 and 1 μm. The period of the nanopillar is not intended to be limited to 400 nm, but can be any value between 100 nm and 3 μm. The material of the nanopillar is not intended to be limited to TiO2, but can also be SiO2, SiN, etc. x The light-reflecting layer can be a medium material or a metal material such as gold or aluminum. The light-reflecting layer is not intended to be limited to a 100nm thick aluminum film, but can be a thin layer formed of any metal material with high light reflectivity, such as a thin layer formed of gold, silver, or aluminum, preferably aluminum, and the thickness can be between 50nm and 1μm.

[0049] The period, linewidth (or diameter), and height of nanopillar array units (individual pixels) with different colors are at least one different. The structural color of the nanopillar array unit can thus be modulated independently.

[0050] The third embodiment of this application discloses a method for manufacturing a structural color display device. The method includes:

[0051] Step 1: Obtain a table of processing parameters for the nanopillar array units and their corresponding display colors. The processing parameters include the height, linewidth, and period of the nanopillar array units.

[0052] This step involves fabricating multiple nanopillar array units on a substrate, such that at least one of the height, linewidth, and period parameters of the multiple nanopillar array units is different. The multiple nanopillar array units are illuminated with visible light, and the structural color displayed by a particular nanopillar array unit is observed and recorded using a microscope. This yields a table of fabrication parameters that corresponds one-to-one with the displayed color of the nanopillar array unit (i.e., height, linewidth, and period). Where experimental conditions permit, a sufficient number of nanopillar array units can be fabricated to ensure that the displayed structural color covers as much of the HSB space as possible. In addition, the processing amount should also include the values ​​of m and n in the m×n configuration of the nanopillar array unit (which have basically no effect on the color of the pixel). Preferably, m and n can be selected in the range of less than 10, and more preferably in the range of less than 5. In order to make the nanopillar array units with different structural colors maintain a consistent single pixel size as much as possible, the nanopillar array units with a larger sum of linewidth and period can be configured with smaller m and n, such as 2×2 or 2×3, while the nanopillar array units with a smaller sum of linewidth and period can be configured with larger m and n, such as 3×3, 3×4 or 4×4.

[0053] Step 2: For each pixel of the target image, determine the corresponding structural color (i.e., the same or closest to it) in the processing parameter table. This determines the processing amount of each nanopillar array unit on the metasurface corresponding to the image. For example, for the (i,j)th pixel in a k×k pixel target image, obtain the color of that pixel and find the processing amount corresponding to that color in the processing parameter table. Thus, the processing amount of the nanopillar array unit at the (i,j)th pixel is determined.

[0054] Step 3: Fabricate nanopillar array units at the specified locations on a substrate of a predetermined size, according to the amount of nanopillar array units corresponding to each pixel of the target image. This generates a metasurface layer arranged on the substrate surface based on the total number of pixels in the target image. For example, grayscale electron beam lithography and atomic layer deposition methods can be used to fabricate the nanopillar array units; however, these methods are merely examples, and other micro / nano fabrication methods known in the art can also be used. Under visible light irradiation, the metasurface layer fabricated on the substrate of the predetermined size reflects visible light with specific amplitude and frequency due to the predetermined arrangement of each nanopillar array unit, thus forming a desired similar appearance on the observation surface. Figure 5 The shown is a fixed colored pattern.

[0055] The fourth embodiment of this application provides an apparatus for fabricating a structural color display device. The apparatus includes a control unit and a processing unit, wherein the processing unit can be a micro / nano structure processing unit commonly used in the art.

[0056] The control unit stores a predetermined processing parameter table, which may be, for example, a one-to-one correspondence table between a specific color obtained by measuring a large number of nanopillar array units with different processing amounts produced in the early stage and the processing amount of a specific nanopillar array unit that achieves that color.

[0057] After acquiring a target image that is to be processed on a structural color display device, the control unit is configured to determine the expected color of each pixel of the target image, determine the structural color corresponding to each pixel (the structural color should be as close as possible to the expected color), and thereby determine the processing amount of the nanopillar array unit corresponding to each pixel according to the processing parameter table.

[0058] The control unit is configured to control the processing unit to fabricate a metasurface layer on a target substrate layer according to the amount of processing of the nanopillar array unit corresponding to each pixel, so as to fabricate the structural color display device for displaying the target image, wherein the metasurface layer is composed of all the nanopillar array units corresponding to the target image.

[0059] The methods or apparatus described in various embodiments of this application are based on multi-dimensional control of structural color achieved through simultaneous adjustment of structural height, width, and period. In contrast, the micro / nano structures constituting traditional structural color devices only have adjustable structural features in the planar direction, thus making it difficult to achieve rich structural color display capabilities, such as simultaneous control of structural color hue, saturation, and brightness. Furthermore, while traditional display devices offer a relatively rich color palette, their pixel sizes are generally large, making them unsuitable for micro-display devices and high-resolution devices. The methods described in this embodiment overcome these difficulties. The introduction of a height gradient structure significantly increases the controllable dimensions of the structure, enabling simultaneous control of structural color hue, saturation, and brightness. The methods described in this embodiment also significantly reduce the structural pixel size, greatly improving the image display resolution.

[0060] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

[0061] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0062] The block diagrams of devices, structures, methods, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0063] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0064] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0065] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for fabricating a structural color display device, wherein the structural color display device comprises a substrate layer and a plurality of nanopillar array units located thereon, the nanopillar array units having a plurality of nanopillars extending above the substrate layer, the method comprising: The structural color corresponding to each pixel of the target image is determined, and the processing amount of the nanopillar array unit corresponding to each pixel is determined according to the processing parameter table. The processing parameter table indicates the relationship between the structural color displayed by the nanopillar array unit and the corresponding processing amount. The processing amount includes the height, line width and period of the nanopillar. The height indicates that the nanopillar is higher than the substrate layer. The line width indicates the cross-sectional dimension of the nanopillar along the substrate layer. The period indicates the distance from the center to the center of two adjacent nanopillars. Based on the amount of nanopillar array units fabricated for each pixel, a metasurface layer is fabricated on the target substrate to create the structural color display device capable of displaying the target image, wherein the metasurface layer is composed of all the nanopillar array units corresponding to the target image; The processing parameter table mentioned above is determined by fabricating multiple nanopillar array units with different processing amounts on the test substrate layer and observing the structural color displayed by each nanopillar array unit. The fabrication of multiple nanopillar array units with different fabrication amounts on the test substrate layer includes: The structural color brightness of the nanopillar array unit can be changed at least by adjusting the height of the nanopillars; At least by adjusting the period of the nanopillars, the structural color and hue of the nanopillar array units can be changed; and The structural color saturation of the nanopillar array unit can be changed at least by adjusting the linewidth of the nanopillars.

2. The method for fabricating a structural color display device according to claim 1, further comprising first fabricating a light-reflecting layer on the target substrate layer, and then fabricating the metasurface layer on the light-reflecting layer, wherein the light-reflecting layer has a reflective effect on light transmitted from the metasurface layer to it.

3. A structural color display device manufactured according to the method of claim 1, comprising a substrate layer and a metasurface layer thereon, characterized in that, The metasurface layer comprises a plurality of nanopillar array units, each nanopillar array unit having a plurality of nanopillars forming a rectangular array; the nanopillar array units are capable of receiving and modulating incident light, thereby causing the emitted light to have a specific frequency and display a specific structural color; and wherein... The nanopillar array unit is configured to determine the specific frequency of the emitted light based on the height, linewidth, and period of the nanopillars therein, wherein the height represents the height of the nanopillar above the substrate, the linewidth represents the cross-sectional dimension of the nanopillar along the substrate, and the period represents the center-to-center distance between two adjacent nanopillars.

4. The structural color display device according to claim 3, characterized in that, It also includes a light-reflecting layer disposed between the substrate layer and the metasurface layer, wherein the light-reflecting layer reflects light transmitted from the metasurface layer to it so that the transmitted light passes a second time through the nanopillar array units of the metasurface layer and is modulated therein to increase the proportion of emitted light at the specific frequency.

5. The structural color display device according to claim 3, characterized in that, The substrate is configured to provide support for the metasurface layer, and the substrate is fused silica, sapphire wafer, silicon wafer, gallium arsenide wafer, or SiN supported by a grid. x One of the following: thin film material window or SiO2 thin film material window; and The thickness of the substrate layer can be configured to be between 100 nm and 1 μm, between 1 μm and 500 μm, or between 500 μm and 1 mm.

6. The structural color display device according to claim 3, characterized in that, The nanopillar array units have a size between 1 μm and 3 μm, enabling the structured color display device to achieve a resolution of 6.4 × 10⁻⁶. 8 dpi-7.2×10 7 Between dpi.

7. The structural color display device according to claim 3, characterized in that, The materials constituting the nanopillars include SiO2 and SiN. x At least one of TiO2, gold, and aluminum; and The height of the nanopillar is configured to be between 0 and 1 μm, the linewidth of the nanopillar is configured to be between 50 nm and 500 nm, the period of the nanopillar is configured to be between 100 nm and 3 μm, and the cross-section of the nanopillar is one of a circle, an ellipse, or a polygon.

8. The structural color display device according to claim 4, characterized in that, The material constituting the light-reflecting layer is at least one of gold, silver and aluminum to have high light reflectivity, and its thickness is configured to be between 50 nm and 1 μm.

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