Color generating structure and method for manufacturing a color generating structure

Abstract

A color generation structure (1) comprises: a substrate (2) having a reflection surface (2a) that reflects light; and a plurality of columnar structures (4) located on the reflection surface (2a). The plurality of columnar structures (4) have a dimension and a period (P) that are less than or equal to the wavelength of visible light. The columnar structure (4) is configured to contain resin. The refractive index of the columnar structure (4) is higher than the refractive index of a substance that fills a space (A), the space (A) being a space over the reflection surface (2a) where the plurality of columnar structures (4) are not formed. At least one of the refractive index, dimension, shape, and period (P) of the plurality of columnar structures (4) is controlled such that guided-mode resonance is induced within the plurality of columnar structures (4) and between the plurality of columnar structures (4) and the reflection surface (2a) and light in a specific wavelength range is absorbed at the reflection surface (2a).

Description

[Technical Field]

[0001] The present invention relates to a color generation structure and a method for manufacturing a color generation structure. [Background technology]

[0002] In recent years, there has been a surge in research applying microstructures involving collective electron excitation (so-called surface plasmon resonance) to subwavelength-scale color printing. For example, techniques have been disclosed for generating various colors by forming metal microstructures on a substrate. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Masashi Miyata, Hideaki Hatada, and Junichi Takahara, “Full-Color Subwavelength Printing with Gap-Plasmonic Optical Antennas,” Nano Letters 2016 16 (5), 3166-3172, DOI: 10.1021 / acs.nanolett.6b00500 [Non-Patent Document 2] Kumar, K., Duan, H., Hegde, R. et al. ”Printing color at the optical diffraction limit.,” Nature Nanotech 7, 557-561 (2012). https: / / doi.org / 10.1038 / nnano.2012.128 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] On the other hand, conventional technologies used methods with very low throughput, such as electron beam lithography, to form microstructures. Therefore, it was extremely difficult to reduce the manufacturing cost of color-generating structures.

[0005] The present invention aims to reduce the manufacturing cost of color-generating structures. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the color generating structure according to the present invention comprises a substrate having a reflective surface that reflects light, and a plurality of columnar structures located on the reflective surface, wherein the plurality of columnar structures have dimensions and periods less than or equal to the wavelength of visible light, the columnar structures are made up of resin, the refractive index of the columnar structures is higher than the refractive index of the material filling the space on the reflective surface where the plurality of columnar structures are not formed, and at least one of the refractive index, dimensions, shape and period of the plurality of columnar structures is controlled to induce waveguide mode resonance inside the plurality of columnar structures and between the plurality of columnar structures and the reflective surface, so that light of a specific wavelength band is absorbed at the reflective surface.

[0007] Further, the method for manufacturing a color generation structure according to the present invention includes a step of preparing a soft mold having a plurality of concave portions corresponding to a plurality of columnar structures formed on its surface, and a substrate having a reflecting surface for reflecting light; a step of applying a resin film on the reflecting surface; a step of pressing the surface of the soft mold against the resin film to transfer a pattern to the resin film; a step of curing the resin film on which the pattern has been transferred to form the columnar structure on the reflecting surface; and a step of detaching the soft mold from the substrate. The refractive index of the columnar structure is higher than the refractive index of a substance filling a space on the reflecting surface where the plurality of columnar structures are not formed, and at least one of the refractive index, dimensions, shape, and period of the plurality of columnar structures is controlled so as to induce waveguide mode resonance inside the plurality of columnar structures and between the plurality of columnar structures and the reflecting surface, and light in a specific wavelength band is absorbed by the reflecting surface.

Advantages of the Invention

[0008] According to the present invention, it is possible to reduce the manufacturing cost of the color generation structure.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the schematic configuration of a color generation structure according to an embodiment. [Figure 2] FIG. 2 is a plan view showing an example of the schematic configuration of a color generation structure according to an embodiment. [Figure 3] FIG. 3 is a view showing an example of the manufacturing process of a color generation structure according to an embodiment. [Figure 4] FIG. 4 is a view showing another example of the manufacturing process of a color generation structure according to an embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing another example of the schematic configuration of a color generation structure according to an embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing another example of the schematic configuration of a color generation structure according to an embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing the configuration of the color generation structure of Example 1. [Figure 8] Figure 8 shows the width dependence of the reflectance spectrum in the color generation structure of Example 1. [Figure 9] Figure 9 shows the width dependence of the CIE1931 chromaticity diagram in the color generation structure of Example 1. [Figure 10] Figure 10 shows the periodic dependence of the reflectance spectrum in the color generation structure of Example 1. [Figure 11] Figure 11 shows the periodic dependence of the CIE1931 chromaticity diagram in the color generation structure of Example 1. [Figure 12] Figure 12 is a plan view showing the configuration of the color generation structure in Example 2. [Figure 13] Figure 13 shows the width dependence of the reflectance spectrum in the column direction (for x-polarization) in the color generation structure of Example 2. [Figure 14] Figure 14 shows the width dependence of the reflectance spectrum in the column direction (for y-polarization) in the color generation structure of Example 2. [Figure 15] Figure 15 is a plan view showing the configuration of the color generation structure in Example 3. [Figure 16] Figure 16 shows the periodic dependence of the reflectance spectrum in the column direction (in the case of x-polarization) in the color generation structure of Example 3. [Figure 17] Figure 17 shows the periodic dependence of the reflectance spectrum in the column direction (in the case of y-polarization) in the color generation structure of Example 3. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. The shapes, sizes, positions, etc., shown in the drawings are approximate and do not limit the present invention. The same elements are denoted by the same reference numerals, and redundant explanations are omitted.

[0011] Figure 1 is a cross-sectional view showing an example of the schematic configuration of the color generation structure 1 according to the embodiment, and Figure 2 is a plan view showing an example of the schematic configuration of the color generation structure 1 according to the embodiment. As shown in Figures 1 and 2, the color generation structure 1 according to the embodiment comprises a substrate 2, a dielectric layer 3, and a plurality of columnar structures 4.

[0012] The substrate 2 is, for example, a flat plate and has a reflective surface 2a on its flat main surface. The substrate 2 is made of a material that has a negative dielectric constant in the visible light region. The substrate 2 is mainly composed of Al (aluminum), Ag (silver), Au (gold), Cu (copper), Cr (chromium), or Fe (iron).

[0013] In the example shown in Figure 1, the exposed surface of the substrate 2 is the reflective surface 2a. However, this disclosure is not limited to this example, and a separate metal layer may be provided on the main surface of the substrate 2, with the reflective surface 2a being formed by this metal layer. In this case, the substrate 2 may be made of any material, and the metal layer forming the reflective surface 2a should be made of a material having a negative dielectric constant in the visible light region.

[0014] The dielectric layer 3 is located between the reflective surface 2a of the substrate 2 and the plurality of columnar structures 4. The dielectric layer 3 is provided, for example, with a substantially uniform thickness across the entire surface of the reflective surface 2a. The dielectric layer 3 is composed of a material having a positive dielectric constant in the visible light region. The thickness of the dielectric layer 3 is, for example, 5 nm to 100 nm.

[0015] The dielectric layer 3 is mainly composed of, for example, silicon oxide (SiO2), aluminum oxide (Al2O3), indium tin oxide (ITO), magnesium fluoride (MgF2), or calcium fluoride (CaF2).

[0016] The multiple columnar structures 4 are located on the reflective surface 2a of the substrate 2. Specifically, the multiple columnar structures 4 are located on the surface of the dielectric layer 3 located on the reflective surface 2a of the substrate 2. The multiple columnar structures 4 are arranged, for example, in a matrix (two-dimensional array) on the reflective surface 2a of the substrate 2.

[0017] The columnar structure 4 has dimensions less than or equal to the wavelength of visible light. The height of the columnar structure 4 is, for example, 10 nm to 400 nm. The width W of the columnar structure 4 (see Figure 7) is, for example, 10 nm to 400 nm.

[0018] Furthermore, the multiple columnar structures 4 have a period (pitch) P (see Figure 7) that is less than or equal to the wavelength of visible light. The period P of the multiple columnar structures 4 is, for example, 10 nm to 400 nm.

[0019] The columnar structure 4 is, for example, a rectangular prism, as shown in Figures 1 and 2. However, the columnar structure 4 of this disclosure is not limited to a rectangular prism. For example, the planar shape of the columnar structure 4 may be a quadruple rotationally symmetric structure (polarization-independent operation) including a circle, or a double rotationally symmetric structure (polarization-dependent operation) including a rectangle.

[0020] In this embodiment, the columnar structure 4 is composed of resin. Multiple columnar structures 4 are formed by nanoimprint lithography (NIL), which is described below.

[0021] Figure 3 shows an example of the manufacturing process of the color generation structure 1 according to the embodiment. First, as shown in Figure 3(a), a master mold 10 is prepared. Such a master mold 10 is made of, for example, silicon or quartz and has a plurality of protrusions 10a on a flat surface.

[0022] These multiple protrusions 10a are located in the same positions and have the same dimensions as the multiple columnar structures 4 (see Figure 1) in the color generation structure 1 (see Figure 1), and are formed by known techniques such as electron beam lithography.

[0023] Next, as shown in Figure 3(b), a soft mold 20 is prepared using the prepared master mold 10. The soft mold 20 is made of, for example, resin and is supported by a support plate 30.

[0024] Then, the soft mold 20 is pressed against the master mold 10, and the pattern of the master mold 10 is transferred, so that a plurality of recesses 20a are formed in the soft mold 20, as shown in Figure 3(c). These plurality of recesses 20a have positions and dimensions that correspond to the plurality of columnar structures 4.

[0025] Furthermore, in parallel with the processes shown in Figures 3(a) to 3(c) described above, the substrate 2 is prepared as shown in Figure 3(d). For example, the flat main surface of the substrate 2 becomes a reflective surface 2a through mirror polishing or other processes, and a dielectric layer 3 is provided on this reflective surface 2a. In this disclosure, the substrate 2 may also be prepared by continuously depositing a metal layer that will become the reflective surface 2a and a dielectric layer 3 on the flat main surface of the substrate 2.

[0026] Next, as shown in Figure 3(e), a resin film 40 is formed on the reflective surface 2a of the substrate 2. This resin film 40 is composed of, for example, a UV (ultraviolet) curing resin.

[0027] Next, as shown in Figure 3(f), the surface of the soft mold 20 is pressed against the resin film 40 on the substrate 2, and the pattern of the soft mold 20, which is composed of multiple recesses 20a, is transferred to the resin film 40.

[0028] Next, as shown in Figure 3(g), ultraviolet UV light is irradiated onto the resin film 40 onto which the pattern of the soft mold 20 has been transferred, and the resin film 40 is cured. As a result, the resin film 40 hardens and becomes a plurality of columnar structures 4. This ultraviolet UV light is irradiated, for example, through the soft mold 20.

[0029] Finally, the soft mold 20 is detached from the substrate 2, and the color generation structure 1 according to the embodiment is formed as shown in Figure 3(h).

[0030] Figure 4 shows another example of the manufacturing process of the color generation structure 1 according to the embodiment. First, as shown in Figure 4(a), a master mold 10 is prepared. Next, as shown in Figure 4(b), a soft mold 20 is prepared using the prepared master mold 10.

[0031] Then, as the soft mold 20 is pressed against the master mold 10 and the pattern is transferred, multiple recesses 20a are formed in the soft mold 20, as shown in Figure 4(c).

[0032] Furthermore, in parallel with the processes described in Figure 4(a) to (c) above, the substrate 2 is prepared as shown in Figure 4(d). Note that the processes described in Figure 4(a) to (d) above are the same as the processes in Figure 3(a) to (d) above, so a detailed explanation is omitted.

[0033] Next, as shown in Figure 4(e), a resin film 40A is formed on the reflective surface 2a of the substrate 2. In this other example, the resin film 40A is composed of, for example, a thermosetting resin.

[0034] Next, as shown in Figure 4(f), the surface of the soft mold 20 is pressed against the resin film 40A on the substrate 2, and the pattern of the soft mold 20, which is composed of multiple recesses 20a, is transferred to the resin film 40A.

[0035] Next, as shown in Figure 4(g), heat H is supplied to the resin film 40A onto which the pattern of the soft mold 20 has been transferred, causing the resin film 40A to harden. As a result, the resin film 40A hardens and forms multiple columnar structures 4. This heat H is supplied, for example, via the substrate 2.

[0036] Finally, the soft mold 20 is detached from the substrate 2, and a color generation structure 1 according to another example is formed, as shown in Figure 4(h).

[0037] Thus, in this embodiment, since a microstructure can be formed on the substrate 2 by the soft mold 20 onto which the pattern of the master mold 10 has been transferred, the throughput of the color generation structure 1 can be improved. Therefore, according to this embodiment, the manufacturing cost of the color generation structure 1 can be reduced.

[0038] Furthermore, in this embodiment, even if the substrate 2 has a large area, all columnar structures 4 on the substrate 2 can be formed at once by a single transfer process. Therefore, according to this embodiment, it becomes possible to easily increase the area of ​​the color generation structure 1.

[0039] Furthermore, the color generation structure 1 according to this embodiment can form a large-area microstructure pattern on the order of meters by pattern-transferring multiple columnar structures 4 using a roll-to-roll method, in which a roll-shaped mold is pressed onto resin and rotated while curing.

[0040] In this embodiment, at least one of the refractive index, dimensions, shape, and period P of the multiple columnar structures 4 is controlled so that waveguide mode resonance is induced inside the multiple columnar structures 4 and between the multiple columnar structures 4 and the reflective surface 2a, and so that light of a specific wavelength band is absorbed at the reflective surface 2a.

[0041] For example, in this embodiment, the multiple columnar structures 4 have dimensions and period P that are less than or equal to the wavelength of the visible light they absorb and reflect (where λ is the wavelength of the incident light, and n is the refractive index of the material (for example, air) filling the space A on the reflective surface 2a where the multiple columnar structures 4 are not formed (see Figure 1), then λ / n or less).

[0042] This allows for strong coupling of light of a specific wavelength band incident from above the multiple columnar structures 4 with the waveguide mode resonances present within the multiple columnar structures 4 and between the multiple columnar structures 4 and the reflective surface 2a, resulting in strong absorption of the coupled light at the reflective surface 2a.

[0043] In this case, light in the non-resonant wavelength range is strongly reflected by the reflective surface 2a, so the reflectance wavelength spectrum drops significantly only in the resonant and absorbed light wavelength range.

[0044] In other words, in this embodiment, the reflectance spectrum in the color generation structure 1 can be controlled with a high degree of freedom by designing a microstructure that includes multiple columnar structures 4, and consequently, the color of the reflected light can be controlled.

[0045] Furthermore, since the coupling conditions between incident light and waveguide mode resonance strongly depend on the in-plane design dimensions, such as the shape and period of the microstructure, the color of the reflected light can be controlled solely by the in-plane pattern of the microstructure. Therefore, according to this embodiment, various colors can be generated in the color generation structure 1.

[0046] Furthermore, it is preferable that the refractive index of the resin constituting the columnar structure 4 is greater than the refractive index of the substance (for example, air) that fills the space A on the reflective surface 2a where no columnar structures 4 are formed.

[0047] As a result, the color generation structure 1 according to this embodiment can induce waveguide mode resonance on the reflective surface 2a, thereby enabling the generation of various colors.

[0048] Furthermore, in the embodiment, it is preferable that the columnar structure 4 is composed of a fine particle mixed resin, which is obtained by mixing fine particles of an inorganic material with a resin. This makes it possible to control the refractive index of the columnar structure 4 to a value higher than the refractive index of the base resin. Therefore, according to the embodiment, a wider variety of colors can be generated in the color generating structure 1.

[0049] The fine particles mixed into the columnar structure 4 are preferably materials that have a higher refractive index in the visible light region compared to general glass or resin materials, such as silicon (Si), zirconium oxide (ZrO2), or titanium oxide (TiO2).

[0050] Furthermore, in this embodiment, since the resin columnar structure 4 is formed on the substrate 2 by the nanoimprint lithography described above, it is preferable that the dielectric layer 3 to which the columnar structure 4 adheres is made of a material that has high adhesion to resin, such as silicon oxide or aluminum oxide.

[0051] In this disclosure, it is not necessarily required that a dielectric layer 3 be placed between the reflective surface 2a and the plurality of columnar structures 4. For example, as shown in Figure 5, a resin layer 3A may be placed between the reflective surface 2a and the plurality of columnar structures 4.

[0052] Furthermore, the resin layer 3A may be integrally formed with a plurality of columnar structures 4. This also allows for the generation of various colors in the color generation structure 1.

[0053] Furthermore, although the example in Figure 5 shows a case where only the resin layer 3A is placed between the reflective surface 2a and the multiple columnar structures 4, the present disclosure is not limited to such an example. For example, a laminate of the dielectric layer 3 (see Figure 1) and the resin layer 3A may be placed between the reflective surface 2a and the multiple columnar structures 4.

[0054] Furthermore, as shown in Figure 6, multiple columnar structures 4 may be directly supported on the reflective surface 2a. This also allows the color generation structure 1 to generate a variety of colors.

[0055] [Example 1] Next, we will describe Example 1. Figure 7 is a cross-sectional view showing the configuration of the color generation structure 1 in Example 1. In this Example 1, as shown in Figure 2, a plurality of columnar structures 4 that are square in plan view (i.e., a 4-fold rotationally symmetric structure) are arranged in a matrix, and we will describe the simulation results when the period P in the row direction and the period P in the column direction are equal.

[0056] In other words, in Example 1, as shown in Figure 7, multiple columnar structures 4 with a width W corresponding to one side of a square are arranged along the row and column directions with a period P. The simulation results when these widths W and period P are used as design parameters will be explained.

[0057] In this Example 1 and in Examples 2 and 3 described thereafter, the refractive index of the columnar structure 4 is set to n1 = 1.9 by incorporating titanium oxide fine particles into the columnar structure 4. Also, in Examples 1 to 3, the height of the columnar structure 4 is 100 nm. Furthermore, in Examples 1 to 3, the substrate 2 constituting the reflective surface 2a is aluminum, and the dielectric layer 3 is silicon oxide (thickness 20 nm).

[0058] Figure 8 shows the width W dependence of the reflectance spectrum in the color generation structure 1 of Example 1. Figure 8 shows the reflectance spectra when the width W is varied while the period P of the multiple columnar structures 4 is fixed at P=400 (nm). In the example in Figure 8, a plane wave is incident perpendicularly to the reflective surface 2a as the incident light.

[0059] As shown in Figure 8, in Example 1, two dips in reflectivity appear when the width W is changed. The wavelengths λ at which these two dips appear strongly depend on the width W of the columnar structure 4.

[0060] These dips correspond to the waveguide mode resonances of light or surface plasmons present in the color generation structure 1. The coupling condition between these waveguide mode resonances and incident light is when the wavelength λ satisfies equation (1) below. P=m·λ / n eff (m=±1,±2,…) ···(1)

[0061] Here, n eff n is the effective refractive index of the in-plane light (or surface plasmon) waveguide mode of the color generation structure 1 of this disclosure. Since this in-plane waveguide mode strongly depends on the width W of the columnar structure 4 and the period P of the multiple columnar structures 4, the effective refractive index n is also important. eff It strongly depends on the width W and the period P.

[0062] In other words, as shown in Figure 8, when the period P is fixed, the wavelength λ that satisfies the coupling condition is the effective refractive index n eff This depends on the effective refractive index n eff Since λ is a function of the width W, the wavelength λ strongly depends on the width W.

[0063] During resonance, strong light absorption occurs due to the influence of the reflective surface 2a, which has high light loss. As a result, the effect of this light absorption appears as a large dip in the reflectance spectrum, as shown in Figure 8.

[0064] Figure 9 shows the width W dependence of the CIE1931 chromaticity diagram in the color generation structure 1 of Example 1. Note that the chromaticity diagram shown in Figure 9 uses the CIE light source D65 as the incident light.

[0065] As shown in Figure 9, in Example 1, the hue changes significantly as the width W of the columnar structure 4 is changed, indicating that the color generating structure 1 covers a variety of colors.

[0066] As shown in Figures 8 and 9, in Example 1, the reflectance spectrum and the color of the reflected light of the color generation structure 1 can be controlled by controlling the width W of the columnar structure 4.

[0067] In other words, in this embodiment, by modulating the width W of the columnar structure 4 according to its position within the reflective surface 2a of the substrate 2, a two-dimensional image (i.e., a color print) composed of multiple colors can be generated.

[0068] Figure 10 shows the period P dependence of the reflectance spectrum in the color generation structure 1 of Example 1. Figure 10 shows the reflectance spectra when the period P is varied while the width W of the columnar structure 4 is fixed at W = 200 (nm). In the example in Figure 10, a plane wave is incident perpendicularly to the reflective surface 2a as the incident light.

[0069] As shown in Figure 10, in Example 1, a single dip in reflectivity appears when the period P is changed. The wavelength λ at which this single dip appears strongly depends on the period P of the multiple columnar structures 4.

[0070] This dependency, like the example in Figure 8 above, can be explained by a change in the coupling conditions between the incident light and the guided mode resonance.

[0071] Figure 11 shows the period P dependence of the CIE1931 chromaticity diagram in the color generation structure 1 of Example 1. In the chromaticity diagram shown in Figure 11, the CIE light source D65 is used as the incident light.

[0072] As shown in Figure 11, in Example 1, the hue changes as the period P of the multiple columnar structures 4 is changed, indicating that the color generating structure 1 covers a variety of colors.

[0073] As shown in Figures 10 and 11, in Example 1, the reflectance spectrum and the color of the reflected light of the color generation structure 1 can be controlled by controlling the period P of the multiple columnar structures 4.

[0074] In other words, in this embodiment, by modulating the period P of multiple columnar structures 4 according to their positions within the reflective surface 2a of the substrate 2, a two-dimensional image (color print) composed of multiple colors can be generated.

[0075] Furthermore, in this embodiment, by modulating the width W of the columnar structure 4 and the period P of the multiple columnar structures 4 according to their position within the reflective surface 2a of the substrate 2, it is possible to generate a two-dimensional image (color print) composed of colors with a high degree of freedom.

[0076] [Example 2] Next, Example 2 will be described. FIG. 12 is a plan view showing the configuration of the color generation structure 1 of Example 2. In this Example 2, as shown in FIG. 12, a plurality of columnar structures 4 having a rectangular shape (i.e., a two-fold rotational symmetry structure) in plan view are arranged in a matrix, and the simulation results when the period P in the row direction and the period P in the column direction are equal will be described.

[0077] That is, in Example 2, as shown in FIG. 12, the width W in the row direction (x-polarized light) of the columnar structure 4 x and the width W in the column direction (y-polarized light) y will be described for the simulation results when they are used as design parameters.

[0078] FIG. 13 is a diagram showing the dependence of the reflectance spectrum in the column direction of the color generation structure 1 of Example 2 on the width W y in the case of x-polarized light. Note that in FIG. 13, the period P of the plurality of columnar structures 4 is P = 400 (nm), and the width W in the row direction of the columnar structure 4 x is fixed to W x = 150 (nm), and the reflectance spectrum of x-polarized light when the width W in the column direction y is changed is shown. Also, in the example of FIG. 13, a plane wave is incident perpendicularly to the reflection surface 2a as the incident light.

[0079] As shown in FIG. 13, in Example 2, it can be seen that the reflection spectrum in x-polarized light has a weak dependence on the width W in the column direction. y

[0080] FIG. 14 is a diagram showing the dependence of the reflectance spectrum in the column direction of the color generation structure 1 of Example 2 on the width W y in the case of y-polarized light. Note that in FIG. 14, the period P of the plurality of columnar structures 4 is P = 400 (nm), and the width W in the row direction of the columnar structure 4 x is fixed to W x = 150 (nm), and the reflectance spectrum of y-polarized light when the width W in the column direction y is changed is shown. Also, in the example of FIG. 14, a plane wave is incident perpendicularly to the reflection surface 2a as the incident light.​

[0081] As shown in Figure 14, in Example 2, the reflection spectrum in y polarization has a width W in the column direction. y It is clear that there is a strong dependence on it.

[0082] Thus, the results of Example 2 show that the reflectance spectra of x-polarized and y-polarized light have a width W along the row and column directions. x , W y This demonstrates that each of these can be controlled almost independently.

[0083] This result indicates that the conditions for guided mode resonance differ depending on the incident polarization, and therefore the width W along any one axis parallel to the plane (for example, an axis along the row direction) is important. x And a width W along one axis perpendicular to it (for example, an axis along the column direction). y This demonstrates that by changing these two factors, the color generation structure 1 will have different reflectance spectra depending on the polarization.

[0084] In other words, in this embodiment, color generation dependent on the incident polarization can be achieved by designing the in-plane shape of the microstructure.

[0085] Furthermore, in this embodiment, it can be used to realize a wider variety of colors by utilizing color mixing when irradiated with unpolarized light, to display different images depending on the polarization, or as a storage information medium for wavelength-polarization multiplexing.

[0086] [Example 3] Next, Example 3 will be described. Figure 15 is a plan view showing the configuration of the color generation structure 1 in Example 3. In this Example 3, as shown in Figure 15, a plurality of columnar structures 4 that are square in plan view (i.e., a 4-fold rotationally symmetric structure) are arranged in a matrix, and the period P in the row direction x and the period P in the column direction y We will now explain the simulation results for different cases.

[0087] In other words, in Example 3, as shown in Figure 15, the period P of the row direction (x-polarization) in the multiple columnar structures 4 x and the period P in the column direction (y-polarization) y We will now explain the simulation results when these are used as design parameters.

[0088] Figure 16 shows the period P in the column direction of the reflectance spectrum in the color generation structure 1 of Example 3. y This figure shows the dependence (in the case of x-polarization). Figure 16 shows the period P in the row direction of multiple columnar structures 4. x P x =400(nm), the width W of the columnar structure 4 is fixed at W=150(nm), and the period P in the column direction is y The reflectance spectra of x-polarized light when the x-polarization is varied are shown. In the example in Figure 16, a plane wave is incident perpendicularly to the reflective surface 2a as the incident light.

[0089] As shown in Figure 16, in Example 3, the reflection spectrum in x-polarization has a period P in the column direction. y It can be seen that the dependence on it is weak.

[0090] Figure 17 shows the period P in the column direction of the reflectance spectrum in the color generation structure 1 of Example 3. y This figure shows the dependence (in the case of y-polarization). Figure 17 shows the period P in the row direction of the multiple columnar structures 4. x P x =400(nm), the width W of the columnar structure 4 is fixed at W=150(nm), and the period P in the column direction is y The reflectance spectra of y-polarized light when the value is varied are shown. In the example in Figure 17, a plane wave is incident perpendicularly to the reflective surface 2a as the incident light.

[0091] As shown in Figure 17, in Example 3, the reflection spectrum in y polarization has a period P in the column direction. y It is clear that there is a strong dependence on it.

[0092] Thus, the results of Example 3 show that the reflectance spectra of x-polarized and y-polarized light have a period P along the row and column directions. x , P y This demonstrates that each of these can be controlled almost independently.

[0093] This result indicates that the conditions for guided mode resonance differ depending on the incident polarization, and therefore the period P along any one axis parallel to the plane (for example, an axis along the row direction) is important. x And a period P along one axis perpendicular to it (for example, an axis along the column direction). y This demonstrates that by changing these two factors, the color generation structure 1 will have different reflectance spectra depending on the polarization.

[0094] In other words, in this embodiment, color generation dependent on the incident polarization can be achieved by designing the in-plane shape of the microstructure.

[0095] Furthermore, in this embodiment, it can be used to realize a wider variety of colors by utilizing color mixing when irradiated with unpolarized light, to display different images depending on the polarization, or as a storage information medium for wavelength-polarization multiplexing.

[0096] Although the present invention has been described above based on specific embodiments, it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from its spirit.

[0097] For example, in each of the embodiments described above, the width W of the columnar structure 4 (width W x , width W y ) and the period P of multiple columnar structures 4 (period P x , period P y While examples have been shown of generating various colors in the color generation structure 1 by controlling the following, the disclosure is not limited to such examples. For example, the disclosure also shows that various colors can be generated in the color generation structure 1 by controlling at least one of the height and refractive index of the columnar structure 4. [Explanation of Symbols]

[0098] 1 color generation structure 2 circuit boards 2a Reflective surface 3. Dielectric layer 4 Columnar structure Space A 20 Soft Molds 20a recess 40, 40A resin film PfuP x , P y period W, W x , W y Width (example of dimensions)

Claims

1. A substrate having a negative dielectric constant in the visible light region and a reflective surface that reflects light, Multiple columnar structures located on the aforementioned reflective surface, Equipped with, Multiple of the columnar structures have dimensions and periods less than or equal to the wavelength of visible light. The columnar structure is made up of resin, The refractive index of the columnar structure is higher than the refractive index of the material filling the space on the reflective surface where the columnar structures are not formed. Inducing waveguide mode resonance inside the multiple columnar structures and between the multiple columnar structures and the reflective surface, At least one of the refractive index, dimensions, shape, and period of the plurality of columnar structures is controlled so that light of a specific wavelength band is absorbed at the reflective surface. The method is characterized by generating color by reflecting light other than the light of a specific wavelength band that is absorbed inside the plurality of columnar structures and between the plurality of columnar structures and the reflective surface, with respect to incident light in the visible light band, at the reflective surface. Color generation structure.

2. The columnar structure is characterized by being composed of a fine particle mixed resin, which is obtained by mixing fine particles of an inorganic material with a resin. The color generation structure according to claim 1.

3. The multiple columnar structures are characterized in that their dimensions are modulated according to their position within the reflective surface of the substrate. The color generation structure according to claim 1 or 2.

4. The plurality of columnar structures are characterized in that their period is modulated according to their position within the reflective surface of the substrate. The color generation structure according to claim 1 or 2.

5. The plurality of columnar structures are characterized in that the dimensions along an arbitrary axis parallel to the reflective surface and the dimensions along another axis perpendicular to the first axis are different from each other. The color generation structure according to claim 1 or 2.

6. The plurality of columnar structures are characterized in that they have a structure in which the period along an arbitrary axis parallel to the reflective surface and the period along another axis perpendicular to the first axis are different from each other. The color generation structure according to claim 1 or 2.

7. The substrate is further characterized by comprising a dielectric layer located between the reflective surface of the substrate and the plurality of columnar structures. The color generation structure according to claim 1 or 2.

8. The process involves preparing a soft mold having multiple recesses on its surface corresponding to multiple columnar structures, and a substrate having a negative dielectric constant in the visible light region and a reflective surface that reflects light. The steps include applying a resin film onto the reflective surface, The process involves pressing the surface of the soft mold against the resin film to transfer a pattern to the resin film, A step of curing the resin film on which the pattern has been transferred to form the columnar structure on the reflective surface, A step of removing the soft mold from the substrate, Includes, The refractive index of the columnar structure is higher than the refractive index of the material filling the space on the reflective surface where the columnar structures are not formed. Inducing waveguide mode resonance inside the multiple columnar structures and between the multiple columnar structures and the reflective surface, At least one of the refractive index, dimensions, shape, and period of the plurality of columnar structures is controlled so that light of a specific wavelength band is absorbed at the reflective surface. The method is characterized by generating color by reflecting light other than the light of a specific wavelength band that is absorbed inside the plurality of columnar structures and between the plurality of columnar structures and the reflective surface, with respect to incident light in the visible light band, at the reflective surface. A method for manufacturing a color-generating structure.

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