JP6801239B2 - Display and articles - Google Patents

Description

The present invention relates to a display body that emits a structural color and an article to which the display body is attached.

A structural color is a color emitted by a fine structure having a wavelength of light, and a display body that emits a structural color is known. As such a display body, a display body having a fine structure formed by an arrangement of fine particles is known. The display body includes, for example, a base material, a reflective layer, and a display layer, and the display layer includes a periodic structure composed of a plurality of fine particles. Of the reflective layers, the surface in contact with the display layer is a flat surface, and the lattices composed of fine particles are arranged along the flat surface and stacked on the flat surface (see, for example, Patent Document 1).

JP-A-2009-223181

By the way, in the above-mentioned display body, the lattice composed of fine particles is arranged along the flat surface, and the particle arrangement surface specified by the fine particles is uniquely specified by the flat surface. Here, the color of the light emitted by the fine particle layer, that is, the wavelength of the light is substantially determined by the refractive index of the display layer, the distance between the particle arrangement planes, and the angle formed by the perpendicular to the display and the observation direction. Therefore, if the refractive index of the display layer is uniform, the color of light emitted in a specific observation direction is limited to one in the configuration in which the particle arrangement surface is uniquely specified by the flat surface.

Therefore, in a display body provided with such a display layer, an image visually recognized from a specific observation direction tends to be a monotonous image composed of one color. Therefore, there is a demand for a display body capable of displaying an image with a higher design as an image displayed by the display body.

An object of the present invention is to provide a display body and an article capable of enhancing the design of the image displayed by the display body.

The display body for solving the above-mentioned problems includes a fine particle layer containing a plurality of fine particles constituting the particle arrangement plane for emitting structural color, and the fine particle layer is the first distance between the particle arrangement planes in the observation direction. It includes a first layer element having a distance and a second layer element having a second distance as a distance between the particle arrangement planes in the observation direction. (A) The distance between the centers of the fine particles, (b) the two-dimensional direction in which the layer elements spread, (c) the two-dimensional direction in which the particle arrangement plane spreads, and (d) the arrangement of the fine particles in the particle arrangement plane. The first distance and the second distance are different from each other because at least one is different from each other between the first layer element and the second layer element.

The article for solving the above-mentioned problem is an article having a display body, and the display body is the above-mentioned display body.

According to the above configuration, the wavelength of the light emitted from the first layer element in the observation direction and the wavelength of the light emitted from the second layer element in the observation direction are different from each other. Therefore, as compared with the configuration in which the wavelength of the light emitted from one fine particle layer in the observation direction is uniform, the types of light emitted from the fine particle layer at the wavelength can be increased, and as a result, the display body is displayed. It is possible to enhance the design of the image.

The display body further includes a support layer including a surface that supports the fine particle layer, and the surface is a first support surface that supports the first layer element and a second support surface that supports the second layer element. When the two-dimensional direction in which the first support surface spreads and the two-dimensional direction in which the second support surface spreads are different from each other, (b) the two-dimensional direction in which the layer element spreads, and (c) the above. It is preferable that at least one of the two-dimensional directions in which the particle arrangement plane spreads differs between the first layer element and the second layer element.

According to the above configuration, by forming the fine particle layer following the surface of the support layer, it is possible to form the first layer element and the second layer element in which the first distance and the second distance are different from each other. ..

In the display body, the direction in which the particle arrangement surface of the first layer element faces and the direction in which the particle arrangement surface of the second layer element faces may be different from each other.

According to the above configuration, since the direction of the particle arrangement surface is different between the first layer element and the second layer element, the particle arrangement surface and the direction of the light emitted from the particle arrangement surface are formed. The angles can be different. As a result, the wavelength of the light emitted from the first layer element and the wavelength of the light emitted from the second layer element can be made different.

In the display body, the curvatures of the first layer element and the second layer element are different from each other, so that (b) the two-dimensional direction in which the layer element spreads and (c) the particle arrangement plane spreads. At least one of the two-dimensional directions may differ from each other between the first layer element and the second layer element.

According to the above configuration, the difference between the curvature of the first layer element and the curvature of the second layer element causes the two-dimensional direction in which the layer element spreads and the particle arrangement between the first layer element and the second layer element. At least one of the two-dimensional directions in which the surface spreads can be different, and as a result, the wavelength of the light emitted by the first layer element and the wavelength of the light emitted by the second layer element can be different.

In the display body, the plurality of the fine particles contained in the first layer element and the plurality of fine particles contained in the second layer element form a plurality of the particle arrangement planes in the layer element to which each of the second layer elements belongs. It is preferable to have.

According to the above configuration, the intensity of the diffracted light emitted from each layer element can be increased as compared with the configuration in which each layer element includes only one fine particle array surface.

In the display body, the two-dimensional direction in which the first layer element spreads and the two-dimensional direction in which the second layer element spreads intersect with each other, and in the first layer element, the two-dimensional direction in which the first layer element spreads. The two-dimensional direction in which the particle arrangement surface spreads is parallel, and in the second layer element, the two-dimensional direction in which the second layer element spreads and the two-dimensional direction in which the particle arrangement surface spreads may intersect.

According to the above configuration, if the angle formed by the first layer element and the second layer element is different from the angle formed by the particle arrangement surface included in the first layer element and the particle arrangement surface included in the second layer element. Can be made.

In the display body, each of the fine particles has a spherical shape, the particle size of each of the fine particles is substantially equal to the particle size of all the other fine particles, and the average particle size of the plurality of fine particles is 0.1 μm or more and 1 μm. The following is preferable.

According to the above configuration, the wavelength of the first-order diffracted light or the second-order diffracted light emitted from the fine particle layer is likely to be included in the visible light region.

In the display body, the two-dimensional direction in which the first layer element spreads and the two-dimensional direction in which the second layer element spreads are equal to each other, the fine particle layer includes a plurality of layer elements, and the plurality of layer elements are the same. The layer is composed of a first layer element and the second layer element. In the fine particle layer, the plurality of layer elements are arranged in one direction, and the period in which the layer elements are arranged is 1 μm or more, and the layer. The area of the layer element may be 2 μm square or more when viewed from a direction orthogonal to the two-dimensional direction in which the element spreads.

According to the above configuration, in each layer element, fine particles having a size capable of emitting light having a structural color can be arranged in an number as many as possible to generate a structural color.

In the display body, the display body has light transmittance, fills the space between the plurality of fine particles, and further includes a coating layer covering the fine particle layer, and the difference between the refractive index of the fine particles and the refractive index of the coating layer is large. It may be 0.02 or more and 0.7 or less.

According to the above configuration, the amount of diffracted light emitted from the display body tends to be large enough to be visually observed.

In the display body, the fine particle layer includes a plurality of the first layer elements, and when viewed from a direction orthogonal to the two-dimensional direction in which the fine particle layer spreads, the fine particle layer is divided into a plurality of pixels. The pixel may include the first layer element.

According to the above configuration, a predetermined image can be formed by a set of light emitted from a first layer element included in a plurality of pixels.

According to the present invention, it is possible to enhance the design of the image displayed by the display body.

The partial cross-sectional view which shows the partial cross-sectional structure of the display body in one Embodiment of the display body which embodies the present invention. The schematic diagram for demonstrating the diffraction of light in a fine particle layer. The perspective view which shows an example of the arrangement of fine particles in a fine particle layer. The perspective view which shows an example of the arrangement of fine particles in a fine particle layer. A partial cross-sectional view showing a partial cross-sectional structure in an example of a display body. A partial cross-sectional view showing a partial cross-sectional structure in an example of a display body. A partial cross-sectional view showing a partial cross-sectional structure in an example of a display body. A partial cross-sectional view showing a partial cross-sectional structure in an example of a support layer. A partial cross-sectional view showing a partial cross-sectional structure in an example of a support layer. A partial cross-sectional view showing a partial cross-sectional structure in an example of a support layer. A partial cross-sectional view showing a partial cross-sectional structure in an example of a display body. A partial cross-sectional view showing a partial cross-sectional structure in another configuration of the fine particle layer. A plan view showing a plan structure of a display body viewed from a direction orthogonal to the two-dimensional direction in which the fine particle layer spreads. The plan view which shows the plane structure of one Embodiment which embodied the article in this invention.

A display body of the present invention and an embodiment embodying an article will be described with reference to FIGS. 1 to 14.

[Display body configuration]
As shown in FIG. 1, the display body 10 includes a base material 11, a support layer 12, and a fine particle layer 13. The support layer 12 has a surface 12S, and at least a part of the surface 12S is a surface having fine irregularities. The base material 11 has a plate shape extending along one surface, and the base material 11 and the support layer 12 have light transmission.

In the display body 10, the fine particle layer 13 contains 13 g of a plurality of fine particles constituting the particle arrangement surface 13s for emitting a structural color. The fine particle layer 13 includes a first layer element 13a and a second layer element 13b. The first layer element 13a has a first distance D1 as a distance between the particle arrangement surfaces 13s in the observation direction OD, and the second layer element 13b has a second distance D2 as a distance between the particle arrangement surfaces 13s in the observation direction OD. Has. At least one of the following (a) to (d) is different between the first layer element 13a and the second layer element 13b.

That is, (a) the distance between the centers of the fine particles 13g, (b) the two-dimensional direction in which the layer elements spread, (c) the two-dimensional direction in which the particle arrangement surface 13s spreads, and (d) the fine particles 13g in the particle arrangement surface 13s. At least one of the arrangements is different from each other between the first layer element 13a and the second layer element 13b. Of these, the arrangement of the fine particles 13g is a state in which a plurality of fine particles 13g are arranged in the particle arrangement surface 13s, and for example, a body-centered cubic structure and a face-centered cubic structure are applicable.

The first distance D1 and the second distance D2 are different from each other because at least one of (a) to (d) is different between the first layer element 13a and the second layer element 13b.

The distance between the display body 10 and the observation point, which is the position of the observer's viewpoint, is significantly larger than the size of the first layer element 13a and the size of the second layer element 13b, and the observation direction. OD is the direction of the observer's line of sight. Therefore, the observation direction OD with respect to the first layer element 13a and the observation direction OD with respect to the second layer element 13b can be considered to be substantially parallel to each other. Not only between the first layer element 13a and the second layer element 13b, but also at each part of the entire display body 10, the observation direction OD with respect to each part can be regarded as parallel to each other.

According to such a display body 10, the wavelength of the light emitted from the first layer element 13a in the observation direction OD and the wavelength of the light emitted from the second layer element 13b in the observation direction are different from each other. Therefore, as compared with the configuration in which the wavelength of the light emitted from one fine particle layer 13 in the observation direction OD is uniform, the types of light emitted from the fine particle layer 13 at the wavelength can be increased, and as a result, the display can be performed. It is possible to enhance the design of the image displayed by the body 10.

The display body 10 may be observed from the direction facing the fine particle layer 13, or may be observed from the direction facing the base material 11. In the fine particle layer 13, a layer composed of a plurality of particles arranged on one particle arrangement surface is a unit layer. In the fine particle layer 13, a plurality of fine particles 13 g are arranged most periodically in the first layer, which is a unit layer in contact with the surface 12S of the support layer 12, and among the fine particle layers 13, the unit layer farther from the first layer is the finer particles. The periodicity in the 13 g sequence is easily disturbed.

In particular, when the surface 12S of the support layer 12 includes two or more portions, the spreading two-dimensional directions of the respective portions are different from each other, and the two portions having different spreading two-dimensional directions are adjacent to each other, the two portions It is considered that a region in which the periodicity is not maintained in the arrangement is likely to occur because the fine particles arranged along different directions are mixed at the boundary between the two. Therefore, in order to clearly obtain the diffraction effect in the fine particle layer 13, the display body 10 is preferably observed from the direction facing the base material 11.

[Wavelength of light emitted from the fine particle layer]
With reference to FIGS. 2 to 4, the principle that the wavelength of the light emitted from the first layer element 13a and the wavelength of the light emitted from the second layer element 13b are different from each other will be described.

FIG. 2 is a diagram conceptually showing the diffraction of light in the fine particle layer 20, and the Z direction in FIG. 2 is a direction perpendicular to the particle arrangement surface 22 of the fine particle layer 20. The X direction and the Y direction are directions orthogonal to the Z direction, respectively, and the particle arrangement surface 22 extends along a two-dimensional direction defined by the X direction and the Y direction. In the fine particle layer 20 in which the fine particles 21 are lined up in a predetermined cycle, when the incident light IL enters the fine particle layer 20, light diffraction that satisfies the following equation (1) occurs according to Bragg's law.

In equation (1), m is the order of diffraction, λ is the wavelength of the diffracted light, n is the refractive index of the colloidal crystal, d is the distance between the particle array planes, that is, the distance between the array planes, θ. Is the angle of incidence of the incident light IL. The colloidal crystal is a structure in which fine particles 21 are arranged in a three-dimensional period and can express a structural color.

The refractive index n can be approximately determined by the refractive index of the volume average between the fine particles 21 and the medium that fills the space between the fine particles 21. When the packing rate of the fine particles is φ, the refractive index of the fine particles 21 is n _P , the refractive index of the medium is n _B , and the refractive index of the colloidal crystal is n _C , the following equation (2) is approximately established.

The formula (1) is emitted in the direction of the angle θ when the incident light IL1 and the incident light IL2 are incident on the particle array surface 22 in which the fine particles 21 are arranged at the distance d between the array surfaces at an angle θ. The light means that the incident light IL1 and IL2 have a wavelength λ such that the optical path difference 2ndsinθ satisfies the equation (1). Further, if the equation (1) is grasped from another viewpoint, even if the incident light is incident from the same angle θ, the emitted light enhanced by the diffraction in the fine particle layer 20 due to the difference in the distance d between the array planes. It can be seen that the wavelength λ changes.

In FIG. 2, the incident light entering the fine particle layer 20 at an angle θ is emitted at an angle θ symmetrical to the incident light with respect to the plane perpendicular to the particle arrangement surface 22. That is, the reflection angle is equal to the incident angle. In FIG. 2, the inclination angle of the particle arrangement surface 22 is 0 degrees, in other words, the particle arrangement surface 22 is horizontal, but as in the configuration described above with reference to FIG. 1, the surface 12S of the support layer 12 However, in the configuration including the inclined surface, the normal direction on the inclined surface is deviated by the inclination angle from the normal direction with respect to the surface extending along the horizontal direction. Therefore, the sin θ in the equation (1) is different from each other in the portions of the surface having different inclinations, which causes a difference in the wavelength λ of the light emitted from each portion. As a result, when the display body 10 is observed from a specific angle, in other words, a specific observation direction, it becomes possible to locally observe different colors.

The average particle size r of the fine particles 21 constituting the fine particle layer 20 is preferably 0.1 μm or more and 1 μm or less, and more preferably 180 nm or more and 380 nm or less. In the equation (1), assuming that the diffraction order m is 1 and the refractive index n is 1, assuming that the angle θ at which the light is incident is 90 degrees, the wavelength λ of the diffracted light is the distance d between the array surfaces. Double.

As the above-mentioned colloidal crystals, a close-packed opal crystal and a non-close-packed colloidal crystal are known. Of these, in the opal crystal, the distance d between the array planes matches the average particle size r of the fine particles 21. Therefore, when the average particle size r of the fine particles 21 is 180 nm or more and 380 nm or less, the opal crystal emits light having a wavelength in the visible light region, and therefore, the light emitted from the opal crystal is visually observed. It becomes easy to do. Even if the average particle size r of the fine particles 21 is outside this range, when the diffracted light having a diffraction order m of 2 is observed or the angle at which the opal crystal is observed is changed, the fine particles 21 are ejected from the opal crystal. The light emitted can be visually recognized.

FIG. 3 shows the schematic structure of the face-centered cubic lattice, and FIG. 4 shows the schematic structure of the body-centered cubic lattice. Note that, in FIGS. 3 and 4, for convenience of illustration, a structure in which one unit cell is stacked on one unit cell is shown.

Among the colloidal crystals, the close-packed opal crystal has a hexagonal close-packed structure or a face-centered cubic structure, and the non-close-packed colloidal crystal has a face-centered cubic structure or a body-centered cubic structure. ing.

As is clear from the above equation (1), the wavelength λ of the light emitted from the fine particle layer to a specific angle θ changes according to the distance d between the array planes. In the face-centered cubic lattice 30 shown in FIG. 3, a first arrangement surface 31 and a second arrangement surface 32 are shown as examples of particle arrangement surfaces that can be set in the unit array. Further, in the body-centered cubic lattice 40 shown in FIG. 4, a first arrangement surface 41 and a second arrangement surface 42 are shown as examples of particle arrangement surfaces that can be set in the unit array.

The first array surfaces 31 and 41 are particle array surfaces horizontal to the bottom surface of the unit cell, and the second array surfaces 32 and 42 are particle array surfaces inclined by 45 degrees with respect to the bottom surface of the unit cell. Is. The distance between the first array surfaces 31 and 41 is the distance d1 between the first array surfaces, and the distance between the second array surfaces 32 and 42 is the distance d2 between the second array surfaces. Assuming that the length of one side of the unit cell is t, the first array face-to-face distance d1 and the second array face-to-face distance d2 in the face-centered cubic lattice 30 are the following equations (3) and (4). Can be represented by.

Further, in the body-centered cubic lattice 40, the first array surface distance d1 and the second array surface distance d2 can be expressed by the following equations (5) and (6).

In this way, if the method of setting the particle array plane changes in one unit cell, the distance d between the array planes changes, and the structure of the unit cell differs, in other words, the arrangement of the fine particles in the particle array plane changes. The distance d between the array planes also changes depending on the difference. In the above equation (1), when the diffraction order m, the refractive index n, and the angle θ at which light is incident are constant, the wavelength λ is proportional to the distance d between the array planes.

Therefore, in the face-centered cubic lattice 30, the wavelength of the light reflected by the second arrangement surface 32 has a length of about 0.7 times the wavelength of the light reflected by the first arrangement surface 31. .. For example, when the wavelength of the light reflected by the first array surface 31 is 700 nm, the wavelength of the light reflected by the second array surface 32 is 490 nm. That is, the color of the light reflected by the first array surface 31 is red, while the color of the light reflected by the second array surface 32 is blue or green, and the light is reflected by each particle array surface. The color of the light is very different.

Further, the distance d between the array planes in the formula (1) is determined by the diameter of the fine particles and the distance between the fine particles 21. That is, the distance d between the array planes is determined by the distance between the centers of the fine particles 21. Among the colloidal crystals, in the opal crystal, the fine particle diameter corresponds to the distance d between the array planes. On the other hand, in the non-closed-packed colloidal crystal, the van der Waals force, which is the electrostatic repulsive force acting between the fine particles, is a physical quantity determined by the diameter of the fine particles and the distance between the fine particles. The distance d between the array planes is determined by both the distance between the fine particles and the distance between the fine particles.

In this way, the distance d between the array planes differs between the opal crystal and the non-close-packed colloidal crystal, but the difference in the distance d between the array planes in the two crystals is due to the lattice constant in each crystal. Also affects. More specifically, in the non-close-packed colloidal crystal, since the fine particles 21 are not in contact with each other, the lattice constant is not determined even if the particle size of the fine particles 21 is determined. In general, it is known that the equation (7) holds in the face-centered cubic structure and the equation (8) holds in the body-centered cubic structure between the average particle size r, the lattice constant a, and the fine particle filling rate φ. There is.

[Number of unit layers in the fine particle layer]
In the fine particle layer 20 described above with reference to FIG. 2, in order to obtain a light diffraction effect, the fine particle layer 20 preferably has two or more unit layers. In other words, in the fine particle layer 20, it is preferable that a plurality of fine particles form a plurality of particle arrangement planes.

Further, in the fine particle layer 13 described above with reference to FIG. 1, a layer to which the plurality of fine particles 13g contained in the first layer element 13a and the plurality of fine particles 13g contained in the second layer element 13b belong to each. In the element, it is preferable that a plurality of particle arrangement surfaces 13s are formed. Since the intensity of the diffracted light increases as the number of particle arrangement surfaces 13s increases, the visibility of the structural color improves as the number of particle arrangement surfaces 13s increases.

Further, if the fine particle layer 20 is configured to include a first portion composed of a predetermined number of unit layers and a second portion composed of a number of unit layers different from the first portion, the first portion. A shade can be added between the structural color in the above and the structural color in the second portion. As a result, the design of the image expressed by the display body is enhanced as compared with the configuration in which such shades cannot be expressed.

In order to increase the number of unit layers constituting the fine particle layer 20, the shape of the support layer may be changed as follows. That is, when the surface of the support layer has a predetermined inclination angle, the difference between the position of one end and the position of the other end of the surface may be increased in the cross section along the thickness direction of the display body. Alternatively, if the difference between the position of one end of the surface and the position of the other end is the same in the cross section along the thickness direction of the display body, the inclination angle of the surface may be increased. Further, the number of unit layers constituting the fine particle layer 20 can be increased by making the particle size of the fine particles 21 smaller.

[Display configuration example]
An example of the configuration of the display body will be described with reference to FIGS. 5 to 7. Hereinafter, three display bodies having different configurations will be described. In each of FIGS. 5 to 7, for convenience of illustration, only a part of the support layer and the fine particle layer of the display body 10 are shown.

[First form]
As shown in FIG. 5, the fine particle layer 52 includes a first layer element 52a and a second layer element 52b, and a two-dimensional direction in which the layer elements spread between the first layer element 52a and the second layer element 52b. Are different from each other. Further, the two-dimensional direction in which the particle arrangement surface 52s in each layer element spreads is also different between the first layer element 52a and the second layer element 52b.

The display body 50 includes a support layer 51, and the support layer 51 includes a surface 51S that supports the fine particle layer 52. The surface 51S includes a first support surface 51S1 that supports the first layer element 52a and a second support surface 51S2, and has a two-dimensional direction in which the first support surface 51S1 spreads and a two-dimensional direction in which the second support surface 51S2 spreads. Are different from each other.

When the base material 11 is arranged along the horizontal direction, the angle at which the surface 51S is tilted with respect to the horizontal direction, that is, the angle formed by the horizontal direction and the surface 51S is the tilt angle. Of the surface 51S, the inclination angle α on the first support surface 51S1 and the inclination angle β on the second support surface 51S2 are different from each other, and the inclination angle α is larger than the inclination angle β. In other words, the support layer 51 is a fine concavo-convex structure, and includes a convex portion including the first support surface 51S1 and a convex portion including the second support surface 51S2.

The particle arrangement surface 52s of the first layer element 52a extends along the first support surface 51S1, and the particle arrangement surface 52s of the second layer element 52b extends along the second support surface 51S2. In each of the first layer element 52a and the second layer element 52b, the fine particles 52 g are arranged at equal intervals along the particle arrangement surface 52s. The distance between the array planes da in the first layer element 52a and the distance between the array planes db in the second layer element 52b are equal to each other.

The two-dimensional direction in which the first support surface 51S1 spreads and the two-dimensional direction in which the second support surface 51S2 spreads, in other words, the direction of the normal with respect to the first support surface 51S1 and the direction of the normal with respect to the second support surface 51S2. They are different from each other. As described above, since the particle arrangement surface 52s of the first layer element 52a is along the first support surface 51S1 and the particle arrangement surface 52s of the second layer element 52b is along the second support surface 51S2, the first layer element The direction of the normal with respect to 52a and the direction of the normal with respect to the second layer element 52b are different from each other.

Here, the light emitted from the first layer element 52a in the predetermined observation direction OD is the emission light EL1, and the light emitted from the second layer element 52b in the same direction as the emission light EL1 is the emission light EL2. is there. Then, the light for emitting the emission light EL1 is the incident light IL1, the light for emitting the emission light EL2 is the incident light IL2, and the angle θ1 at which the incident light IL1 is incident on the first layer element 52a. The angle θ2 at which the incident light IL2 is incident on the second layer element 52b is different from each other.

Therefore, according to the above equation (1), that is, Bragg's law, the wavelength λ1 of the emission light EL1 and the wavelength λ2 of the emission light EL2 are different from each other. As a result, the color of the light emitted by the first layer element 52a and the color of the light emitted by the second layer element 52b are different from each other toward the predetermined observation direction OD.

The display body 50 is often observed in a state of being tilted by 45 degrees with respect to the horizontal direction. At this time, the angle formed by the light traveling straight from the display body 50 with respect to the eyes of the observer observing the display body 50 and the direction of the normal line with respect to the display body 50 is 45 degrees.

Therefore, the angle θ1 of the light incident on the first layer element 52a can be expressed by the following equation (9) using the inclination angle α of the first support surface 51S1.

Then, when the following equation (10) holds for the inclination angle α, the reflected light from the fine particle layer 52 can be obtained.

That is, when the inclination angle α is larger than 0 degrees and smaller than 22.5 degrees, the reflected light from the first layer element 52a can be obtained. Since the same relationship holds for the second layer element 52b, the reflected light from the second layer element 52b can be obtained when the inclination angle β is larger than 0 degrees and smaller than 22.5 degrees. it can. By forming the support layer 51 so as to satisfy these conditions, it is possible to express the structural color on the display body 50 in the most general observation state.

When changing the inclination of the display body 50 with respect to the horizontal direction to an angle other than 45 degrees or observing light having a higher diffraction order, the inclination angle α of the first support surface 51S1 and the first 2 The inclination angle β of the support surface 51S2 may be an angle outside the above range. Even with such a configuration, the emission light EL1 from the first layer element 52a and the emission light EL2 from the second layer element 52b can be observed.

[Second form]
As shown in FIG. 6, the fine particle layer 62 includes a first layer element 62a and a second layer element 62b. The two-dimensional direction in which the first layer element 62a spreads and the two-dimensional direction in which the second layer element 52b spreads intersect with each other, and the direction in which the particle arrangement surface 62s1 in the first layer element 62a faces and the second layer element The directions of the particle arrangement surfaces 62s2 in 62b are different from each other.

The direction in which the particle array planes face is the direction in which the particle array planes face each other. Here, the incident angle of the incident light with respect to the fine particle layer 62 has a predetermined range, but among the incident light, the light having the predetermined incident angle is reflected most, and among the emitted light from the fine particle layer 62. , The intensity of the incident light is the highest. The intensity of the light emitted at the same angle as the incident angle is the highest.

The observer of the display body 60 visually recognizes the light obtained by mixing the highest intensity emitted light and the other emitted light among the emitted light. Therefore, the direction in which the particle arrangement surface 62s1 of the first layer element 62a faces and the direction in which the particle arrangement surface 62s2 of the second layer element 62b faces are the first even if the observer visually recognizes such mixed light. It is preferable that the color of the light emitted from the first layer element 62a and the color of the light emitted from the second layer element 62b are different to the extent that they are visually recognized as different colors. For example, the particle arrangement surface 62s1 of the first layer element 62a is such that the wavelength of the light emitted from the first layer element 62a and the wavelength of the light emitted from the second layer element 62b are different by about 20 nm to 50 nm. It is preferable that the facing direction is different from the facing direction of the particle arrangement surface 62s2 of the second layer element 62b.

When the direction in which the particle arrangement surface 62s1 of the first layer element 62a faces is different from the direction in which the particle arrangement surface 62s2 of the second layer element 62b faces, the incident light IL1 is incident on the first layer element 62a. The angle θ1 to be formed and the angle θ2 at which the incident light IL2 is incident on the second layer element 72b are generally different.

In the first layer element 62a, the spreading two-dimensional direction of the first layer element 62a and the spreading two-dimensional direction of the particle arrangement surface 62s1 are parallel. On the other hand, in the second layer element 62b, the expanding two-dimensional direction of the second layer element 62b and the expanding two-dimensional direction of the particle arrangement surface 62s2 intersect.

On the surface 61S of the support layer 61, the facing direction of the first support surface 61S1 and the facing direction of the second support surface 61S2 are different from each other. In addition, the inclination angle α of the first support surface 61S1 and the inclination angle β of the second support surface 61S2 are different from each other. The first layer element 62a extends along the first support surface 61S1, and the second layer element 62b extends along the second support surface 61S2.

In each of the first layer element 62a and the second layer element 62b, 62 g of fine particles are arranged at equal intervals in the direction along the surface 61S. However, when the incident light IL1 is incident on the first layer element 62a in emitting light in a predetermined observation direction OD, the particle arrangement surface 62s1 along the first support surface 61S1 is a reflection surface, while the particle arrangement surface 62s1 is a reflection surface. When the incident light IL2 is incident on the second layer element 62b, the particle arrangement surface 62s2 intersecting the second support surface 61S2 is the reflection surface.

Therefore, the distance between the array planes da in the first layer element 62a and the distance between the array planes db in the second layer element 62b are different from each other. As described above, the wavelength of the emitted light EL1 emitted from the first layer element 62a due to the different facing directions and inclination angles of the first support surface 61S1 and the second support surface 61S2 from each other. The wavelength λ1 of the emission light EL2 emitted from the second layer element 62b can be made different from each other.

In the first mode and the second mode, the wavelength λ1 of the emission light EL1 and the wavelength λ2 of the emission light EL2 are different from each other in one observation direction OD, while the emission light in the other observation direction OD. The fine particle layer may be configured so that the wavelength λ1 of the EL1 and the wavelength λ2 of the emitted light EL2 are equal to each other. In such a configuration, by changing the observation direction OD, it is possible to give movement to the change in the color of the image displayed by the display body and enhance the eye-catching effect.

[Third form]
As shown in FIG. 7, in the fine particle layer 72, the distance between the fine particles 72 g is the interparticle distance dc. The interparticle distance dc differs between the first layer element 72a and the second layer element 72b.

On the surface 71S of the support layer 71, the two-dimensional direction in which the first support surface 71S1 spreads and the two-dimensional direction in which the second support surface 71S2 spreads are equal to each other, and the inclination angle α of the first support surface 71S1 and the second support surface The inclination angle β of 71S2 is the same angle as each other. The first support surface 71S1 and the second support surface 71S2 are planes parallel to each other.

The first layer element 72a extends along the first support surface 71S1, and the particle arrangement surface 72s of the first layer element 72a also extends along the first support surface 71S1. Further, the second layer element 72b extends along the second support surface 71S2, and the particle arrangement surface 72s of the second layer element 72b also extends along the second support surface 71S2.

Therefore, the direction of the normal with respect to the first layer element 72a and the direction of the normal with respect to the second layer element 72b are parallel to each other. Therefore, when the incident angle θ1 of the incident light IL1 with respect to the first layer element 72a and the incident angle θ2 of the incident light IL2 with respect to the second layer element 72b are equal, the emitted light of the first layer element 72a. The EL1 and the emission light EL2 of the second layer element 72b are emitted in a predetermined observation direction OD which is the same direction.

As is clear from the above equation (1), the wavelength λ1 of the emission light EL1 and the wavelength λ2 of the emission light EL2 are determined by the distance between the array planes d and the angle θ at which the light is incident. In the support layer 71 having a predetermined shape, the emission direction of the light and the angle θ at which the light is incident on the support layer 71, that is, the fine particle layer 72 are determined by setting the observation direction with respect to the display body 70. Therefore, the equation (1) is rewritten as a function of the wavelength λ and the distance d between the array planes.

Therefore, when it is desired to obtain light having a specific wavelength in a certain observation direction OD, the array surface distance d is obtained by the equation (1), and the particle size satisfies the calculated array surface distance d. 72 g of fine particles having the above may be selected. Alternatively, a material that generates a repulsive force between the fine particles 71 g may be selected as the material used for forming the fine particle layer 72 so as to satisfy the calculated distance between the array planes d.

Also in such a display body 70, in the fine particle layer 72, the distance between the array surfaces of the first layer element 72a and the distance between the array surfaces db of the second layer element 72b are different from each other. Therefore, the wavelength of the light emitted by the first layer element 72a and the wavelength of the light emitted by the second layer element 72b in the observation direction OD can be made different from each other.

Of the support layer 71, the portion having the largest distance from the base material in the thickness direction of the display body 70 is the top portion 72t, and in the support layer 71, the top portion 72t included in the first support surface 71S1 and the second support The distance between the top 72t included in the surface 71S2 is the distance p between the tops. In order to suppress the emission of diffracted light from the support layer 71, the distance between the tops p is preferably 1 μm or more. The reason why the distance between the tops is preferably 1 μm or more will be described below.

Equation (11) is known as a condition for appearance of diffracted light by a diffraction grating.

In equation (11), m is the order of diffraction, λ is the wavelength of the diffracted light, p is the distance between the apex, and θ is the angle of incidence of the incident light IL.

When the angle θ at which light is incident is 90 degrees and the diffraction order m is 1, the wavelength λ coincides with the distance p between the tops. The maximum wavelength of visible light is about 750 nm, and in order to prevent diffracted light having a wavelength included in the visible region from being emitted from the display body 70, the distance between the tops p may be set to about 1 μm.

However, in reality, the angle at which the light is incident on the support layer 71 changes to an angle different from the angle θ90 degrees, or diffracted light of the first order or higher is observed. For example, assuming that the angle θ at which light is incident is 15 degrees and the diffraction order m is 2, the distance between the tops p is about 6 μm. Therefore, in order to prevent the diffracted light emitted from the support layer 71 having no fine particle layer 72 from being observed, it is more preferable that the distance between the tops p is 6 μm or more.

The fine particle layer 72 includes a plurality of layer elements, and the plurality of layer elements are composed of a first layer element 72a and a second layer element 72b. In the fine particle layer 72, the plurality of layer elements are arranged along one direction, and the period in which the layer elements are arranged is 1 μm or more. The area of the layer element is preferably 2 μm square or more when viewed from the direction orthogonal to the two-dimensional direction in which the layer element spreads.

According to such a display body 70, 72 g of fine particles having a size capable of emitting light having a structural color can be arranged in each layer element in a number capable of producing a structural color. ..

[Example of support layer shape]
An example of the shape of the support layer will be described with reference to FIGS. 8 to 11. In the following, four support layers having different shapes will be described. Note that in FIG. 11, hatching of the support layer is omitted for convenience of illustrating the light emitted to the outside of the display body via the support layer.

[First shape]
As shown in FIG. 8, on the surface 81S of the support layer 81, the first support surface 81S1 and the second support surface 81S2 are alternately arranged along one direction. The first support surface 81S1 and the second support surface 81S2 have the same inclination angle with respect to the horizontal direction, but the two-dimensional directions in which the surfaces spread, that is, the facing directions of the surfaces are different from each other.

In other words, in the cross section along the thickness direction of the display body, the support layer 81 includes a plurality of convex portions 81a having an isosceles right triangle shape. In the cross section of each convex portion 81a, the lengths of the two sides sandwiching the top are equal to each other. That is, the angle formed by the extending direction of each side and the horizontal direction is the inclination angle, and the inclination angles of each side are equal to each other.

In the support layer 81, between the first support surface 81S1 and the second support surface 81S2, the direction passes through the top of the convex portion 81a and is parallel to the normal direction of the base material 11 on which the support layer 81 is formed. When the axis extending along the axis is the axis of symmetry, the fine particles arranged on the first support surface 81S1 and the fine particles arranged on the second support surface 81S2 can be arranged symmetrically with respect to the axis of symmetry. When the fine particles arranged on each surface are arranged symmetrically with respect to the axis of symmetry, when the display body is tilted in a direction in which the angle formed by the first support surface 81S1 and the vertical direction increases, and when the display body is tilted, the second support surface 81S2 The change in structural color observed in the observation direction is symmetrical between the time when the display body is tilted in the direction in which the angle formed by the vertical direction and the vertical direction increases.

[Second shape]
As shown in FIG. 9, on the surface 82S of the support layer 82, the first support surface 82S1 and the second support surface 82S2 are alternately arranged along one direction. Between the first support surface 82S1 and the second support surface 82S2, the two-dimensional directions in which the surfaces spread are different from each other, and more specifically, the inclination angles with respect to the horizontal direction are different from each other, and the facing directions of the surfaces are different from each other. different.

In other words, in the cross section along the thickness direction of the display body, the support layer 82 includes a plurality of convex portions 82a having a triangular shape, and each convex portion 82a is horizontal between the two sides forming the top. The tilt angles with respect to the direction are different from each other.

In the display body including the support layer 82, when the display body is tilted in a direction in which the angle formed by the first support surface 82S1 and the shaft increases with respect to the axis extending in the direction orthogonal to the horizontal direction, and when the display body is tilted, the second The change in structural color observed in the observation direction is asymmetric between when the display body is tilted in a direction in which the angle formed by the support surface 82S2 and the shaft increases. Further, since the viewing area where the reflected light is observed also differs depending on the inclination angle of the surface 82S, the area where the structural color is observed when the display body is tilted in one direction even if it is tilted by the same angle in each direction, When the display body is tilted in the other direction, there will be a difference from the area where the structural color is observed.

As described above, since the visual range of the light emitted from the fine particle layer and the wavelength of the light can be changed according to the shape of the support layer 82 on the surface 82S, the shape of the support layer 82 on the surface 82S is used. , It is also possible to configure the display body as follows. That is, when the display body is observed from the first observation direction, the first pattern is displayed by the first layer element located on the first support surface 82S1, and when the display body is observed from the second observation direction, the first pattern is displayed. It is also possible to configure the display body so that the second pattern is displayed by the second support surface 82S2. Furthermore, by setting the structural color emitted by the first layer element to red, the first pattern is displayed in red, and by setting the structural color emitted by the second layer element to green, the second pattern is displayed in green. It is also possible to configure the display body as follows.

[Third shape]
As shown in FIG. 10, in a cross section along the thickness direction of the display body, the support layer 83 may include a first region 83a, a second region 83b, and a third region 83c arranged along one direction. Good. The first region 83a includes a plurality of first convex portions 83a1, the second region 83b includes a plurality of second convex portions 83b1, and the third region 83c includes a plurality of third convex portions 83c1.

Each of the first convex portion 83a1, the second convex portion 83b1, and the third convex portion 83c1 has a right-angled triangular shape, while the direction in which the hypotenuse faces and the horizontal between the three convex portions. The inclination angles of the hypotenuses with respect to the direction are different from each other. In each region, the plurality of convex portions included in each region are arranged in one direction.

In the support layer 83, the first convex portion 83a1, the second convex portion 83b1, and the third convex portion 83c1 may be arranged in a predetermined order along one direction, or along one direction. It may be arranged irregularly.

However, if the regions that emit one color are not lined up at a resolution that the observer can see at the distance that the observer observes the display object, the observer cannot recognize the difference in color between the regions. Can not. Therefore, for example, when it is desired to express completely different colors such as red and green in adjacent regions, it is necessary to arrange a plurality of fine structures for emitting each color so as to form a region having a predetermined size. There is.

The resolution of the human eye is about 100 μm to 200 μm when observing an object from a distance of about 30 cm. Therefore, it is preferable that the region where the microstructures for emitting one color are lined up has a size of at least 100 μm square when viewed from a direction orthogonal to the direction in which the display body spreads.

[Fourth shape]
As shown in FIG. 11, in the display body 90, the surface 91S of the support layer 91 includes the first support surface 91S1 and the second support surface 91S2, and is between the first support surface 91S1 and the second support surface 91S2. , The facing directions of each surface are different from each other. In the cross section along the thickness direction of the display body 90, one convex portion 91a is partitioned by the first support surface 91S1 and the second support surface 91S2, and the support layer 91 includes a plurality of convex portions 91a.

The first support surface 91S1 includes a slope having an inclination angle of 45 degrees and a curved surface having a curvature such that the center of curvature is located outside the support layer 91, and the slope is formed in the direction in which the convex portions 91a are arranged. And the curved surface are connected. Similarly, the second support surface 91S2 includes a slope having an inclination angle of 45 degrees and a curved surface having a curvature such that the center of curvature is located outside the support layer 91, and in the direction in which the convex portions 91a are arranged. , The slope and the curved surface are connected.

In each convex portion 91a, the slope of the first support surface 91S1 and the slope of the second support surface 91S2 form a top portion. In the direction in which the convex portions 91a are lined up, the curved surface of the first support surface 91S1 included in one convex portion 91a and the curved surface of the second support surface 91S2 included in the other convex portion 91a are connected, and these two surfaces form a bottom portion. Is forming.

In the display body 90 including the support layer 91, among the light incident on the display body 90 from the direction orthogonal to the spreading direction of the base material, the incident light IL incident on the slope of the second support surface 91S2 is an adjacent convex portion. It is reflected by the fine particle layer 92 toward the slope of the first support surface 91S1 of the 91a. Then, the light incident on the slope of the first support surface 91S1 is emitted by the fine particle layer 92 as emission light EL in the direction in which the light is incident. On the other hand, the incident light IL incident on the bottom of the support layer 91 is reflected only once by the fine particle layer 92, and is emitted as an emission light EL in the direction in which the light is incident.

As described above, the light reflected at the portion of the fine particle layer 92 in contact with the bottom of the support layer 91 and the light reflected at the portion of the fine particle layer 92 in contact with the slope of the first support surface 91S1 are different from each other with respect to the fine particle layer 92. The angles of light incident are different from each other. Therefore, the interference conditions change between the two parts of the fine particle layer 92, so that each part emits different structural colors. While the two structural colors are microscopically different colors, they are visually recognized as a mixed color in which the two structural colors are mixed from the position where the observer displays the display body.

[Apex angle in support layer]
In the support layer, the angle at the top of the convex portion is the apex angle, and the structural color can be observed when observing the display body, that is, the light reflected by the fine particle layer formed on the support surface is observed. The angle range of the incident light that is emitted toward a person is narrower as the apex angle of the convex portion is smaller. That is, the smaller the apex angle of the convex portion, the more the viewing range is limited, which makes it difficult to observe the structural color.

Furthermore, even if the apex angles are the same, the angle range of the incident light described above differs depending on the shape of the convex portion in the cross section along the thickness direction of the display body. For example, in a prism, the length of the slope is the largest when the cross-sectional shape is a right-angled triangle, and in this case, the region where the reflected light is observed on the observer side is the largest. Therefore, when it is desired to increase the area in which the diffracted light can be visually recognized in the display body, that is, to reduce the area in the display body that looks dark and to make almost the entire display body appear bright, the support layer is formed from the apex angle. It is preferable to include a large convex portion.

The larger the apex angle, the smaller the possible lower limit value of the incident angle θ of light in the equation (1). Further, in order to obtain reflected light having a diffraction order m of 1 and an arbitrary wavelength in a specific observation direction, the refractive index n or the distance between the array planes d in the fine particle layer is set to a predetermined value. In order to do so, it is necessary to select the optimum material.

For example, when the angle θ at which light is incident, that is, the angle θ at which light is reflected is 30 degrees, and it is desired to obtain reflected light having a wavelength of 600 nm, the refractive index n is arranged from the equation (1). The value obtained by multiplying the inter-plane distance d by 600 is 600. When the fine particle layer is composed of a densely packed colloidal crystal, that is, an opal crystal, the refractive index n can be regarded as the refractive index of the medium, and the distance d between the array planes can be regarded as the particle size of the fine particles.

Therefore, a combination of a medium having a refractive index of 1 and fine particles having a particle size of 600 nm, a combination of a medium having a refractive index of 1.2 and fine particles having a particle size of 500 nm, and a refractive index of 1.5 Any combination of the medium and the fine particles having a particle size of 400 nm may be selected. Thereby, the reflected light having a wavelength of 600 nm can be obtained in a specific observation direction.

On the other hand, when the fine particle layer is composed of non-close-packed colloidal crystals, the refractive index n and the distance between the array planes d take into consideration the packing factor and the electrostatic repulsive force as described above. Must be sought.

[Other composition of fine particle layer]
Other configurations of the fine particle layer will be described with reference to FIG. In the following, among the above-mentioned forms of the fine particle layer, the fine particle layer described above with reference to FIG. 5 will be described. The configuration described below can also be applied to a fine particle layer having another form.

As shown in FIG. 12, the display body 50 may include a coating layer 53 that fills the space between the plurality of fine particles 52 g and covers the entire fine particle layer 52. The coating layer 53 has light transmittance, and the material for forming the coating layer 53 is, for example, a polymer gel.

Among the above-mentioned colloidal crystals, in the non-close-packed colloidal crystal, 52 g of fine particles constituting the fine particle layer 52 are located apart from each other in the fine particle layer 52. Therefore, the bonding force between the fine particles 52 g is weaker than that of the opal crystal, and the cycle of arrangement of the fine particles in the fine particle layer 52 may be disturbed by vibration applied to the colloidal crystal.

Therefore, in order to use the colloidal crystal as the fine particle layer 52 of the display body 50 while maintaining the cycle of the arrangement in the fine particles 52 g, it is preferable to fix the crystal structure of the colloidal crystal by the coating layer 53.

The material for forming the coating layer 53 is, for example, a polymer gel fixed by irradiation with ultraviolet rays, and examples of the polymer gel include polyacrylamide, gelatin, and polyethylene glycol. Since the coating layer 53 has light transmittance, natural light and light from a light source such as a fluorescent lamp can enter the fine particle layer 52, and the light can be emitted from the fine particle layer 52.

When selecting the material for forming the coating layer 53, it is necessary to pay attention to the difference between the refractive index of the fine particles 52 g and the refractive index of the coating layer 53. When the difference in the refractive index between them is small, the amount of light diffracted by the fine particles 52 g in the coating layer 53 is small, which makes it difficult to visually observe the structural color. Therefore, the difference in refractive index between them is preferably 0.02 or more.

On the other hand, among the commonly available resins, the refractive index of the resin having a relatively high refractive index is about 1.7, and the minimum refractive index that can be considered as the refractive index of 52 g of fine particles is the refraction of air. Assuming that the rate is 1.0, the difference between the refractive index of the fine particles 52 g and the refractive index of the coating layer 53 is about 0.7 at the maximum.

Since the refractive index of the silica fine particles and the polystyrene fine particles that can be used as the fine particles 52 g is 1.4 or more, the difference between the refractive index of the fine particles 52 g and the refractive index of the coating layer 53 is substantially. The maximum is about 0.3. For this reason, when the coating layer 53 covering the fine particles 52 g is formed, the difference between the refractive index of the fine particles 52 g and the refractive index of the coating layer 53 is 0.02 or more and 0.7 or less. The material for forming the coating layer 53 and the material for forming the coating layer 53 may be selected.

[Plane structure of display body]
The planar structure of the display body will be described with reference to FIG. In the following, among the above-described display bodies, the display body described above will be described with reference to FIG. The configuration described below can also be applied to a display body having another form.

As shown in FIG. 13, a plurality of pixels 52p are partitioned in the fine particle layer 52 when viewed from a direction orthogonal to the two-dimensional direction in which the fine particle layer 52 spreads. The display body 50 including the fine particle layer 52 has a rectangular shape when viewed from a direction orthogonal to the two-dimensional direction in which the fine particle layer 52 spreads, and the fine particle layer 52 is a pixel 52p having a rectangular shape. A plurality of pixels 52p in which the shape of one pixel 52p is the same as the shape of all other pixels 52p are partitioned. The plurality of pixels 52p are arranged along one direction and a direction orthogonal to one direction. Each pixel 52p has a size of, for example, 100 μm square or more and 300 μm square or less.

The fine particle layer 52 includes a plurality of first layer elements 52a and a plurality of second layer elements 52b. The plurality of pixels 52p are composed of a plurality of first pixels 52p1 and a plurality of second pixels 52p2. Of these, each first pixel 52p1 is composed of a plurality of first layer elements 52a, while each second pixel 52p2 is composed of a plurality of second layer elements 52b.

Therefore, when observed from a specific observation direction, the color emitted by the first pixel 52p1 and the color emitted by the second pixel 52p2 are different from each other, so that the image displayed by the display body 50 is a plurality of first pixels 52p1. It is an image composed of a portion to be displayed and a portion to be displayed by a plurality of second pixels 52p2.

When viewed from a direction orthogonal to the two-dimensional direction in which the fine particle layer 52 spreads, in the plurality of pixels 52p, the plurality of first pixels 52p1 are arranged so as to display the alphabet "O" and the alphabet "K" as an image. , The plurality of second pixels 52p2 are arranged so as to fill the space between the first pixels 52p1. Therefore, the display body 50 can display an image composed of the alphabets "O" and "K" and their backgrounds.

[Article]
An example of an article having the display body 10 will be described with reference to FIG. In the following, an IC card will be described as an example of the article.

As shown in FIG. 14, the IC card 100 includes a base material 101, an IC chip 102, and a display body 10. The IC chip 102 and the display body 10 are located on one surface of the base material 101 when viewed from a direction orthogonal to the spreading direction of the base material 101.

[Method of forming fine particle layer]
A method for forming colloidal crystals constituting the fine particle layer will be described. Hereinafter, a method for forming a close-packed opal crystal contained in a colloidal crystal and a method for forming a non-close-packed colloidal crystal will be described in order.

As the most common method for producing opal crystals, a method using a phenomenon in which fine particles are self-assembled in the process of agglutination is known. The sedimentation method is known as one of the methods. In the sedimentation method, a plurality of colloidal fine particles having a small surface charge and a uniform particle size are dispersed in a dispersion medium, and the fine particles are precipitated by using gravity. It is a method of arranging or arranging by evaporating the dispersion medium.

In the sedimentation method, when the particle size of the fine particles is 500 nm or less, or when the specific gravity of the colloidal fine particles and the specific gravity of the dispersion medium are about the same, the state in which the fine particles are dispersed becomes an equilibrium state, and the colloidal fine particles are not crystallized. .. As described above, in the precipitation method, various factors such as the particle size of the colloidal fine particles, the difference in specific gravity between the colloidal fine particles and the dispersion medium, the temperature of the reaction system, and the evaporation rate of the dispersion medium affect the crystallization of the colloidal fine particles. Therefore, it is difficult to determine the optimum conditions.

As other methods, a method using physical restrictions is known, and these methods include an advection accumulation method using the capillary force acting between colloidal fine particles at a gas-liquid interface, and an advection method developed from the advection accumulation method. And, an electrophoresis method and the like can be mentioned. In opal crystals, the fine particles are arranged in contact with each other. Therefore, if the particle size of the colloidal fine particles used for forming the colloidal crystal varies, the arrangement of the colloidal fine particles is disturbed and the dispersion medium is dried. In the process of doing so, cracks are likely to occur in the colloidal crystals.

On the other hand, in the non-close-packed colloidal crystal, colloidal fine particles having an electric charge on the surface are dispersed in a liquid, and the colloidal fine particles are periodically arranged by electrostatic repulsion. In the non-close-packed colloidal crystal, the colloidal fine particles crystallize in a separated state, so that the arrangement disorder in the colloidal fine particles due to the variation in particle size is alleviated. Such crystals are known as charged colloidal crystals, but when the repulsive force between the colloidal fine particles is weak, the colloidal fine particles are randomly distributed, so that the repulsive force is sufficient for periodically arranging the colloidal fine particles. Must be large.

In order to increase the electrostatic repulsive force between the colloidal fine particles, it is effective to increase the concentration, ion concentration, and pH of the colloidal fine particles in the dispersion medium. For example, the surface of silica fine particles generally used in the production of colloidal crystals has a plurality of silanol groups (Si-OH), but since only a part of the silanol groups is dissociated in pure water, the number of charges on the surface Is small. Therefore, when an alkali such as sodium hydroxide (NaOH) is added to the dispersion medium, the dissociation of silanol groups proceeds, and the number of charges increases.

In order to form a colloidal crystal, it is generally necessary that the variation in the particle size of the fine particles is 10% or less. Examples of the fine particles that can be prepared so as to satisfy this condition include silica (SiO ₂ ) fine particles, polystyrene (PSt) fine particles, and polymethylmethacrylate (PMMA) fine particles. Further, since silica, polystyrene, and polymethylmethacrylate have relatively large specific gravities, these materials are effective in producing a close-packed colloidal crystal by a precipitation method.

[Method of forming support layer]
The support layer having each of the above-mentioned shapes can be formed by using the following method.
When forming the support layer, first, the original plate for forming the support layer is formed. For example, a photolithography method can be used to form the original plate. In the formation of the original plate using the photography method, first, a substrate such as a glass substrate is prepared, and a photosensitive resist is uniformly applied to one surface of the substrate. Then, an arbitrary region of the photosensitive resist is exposed with an electron beam, a laser, or the like, and the photosensitive resist after exposure is developed to form a resist pattern.

The photosensitive resist is either a positive resist in which the exposed portion of the photosensitive resist dissolves or a negative resist in which the unexposed portion of the photosensitive resist dissolves during development. You may. Then, the resist pattern may be designed according to the selected resist material.

It is possible to use a substrate having a resist pattern as an original plate for forming a support layer on a film or the like, in other words, as a stamper. However, since the resist pattern is brittle, it is not suitable for a stamper for mass production. Therefore, a metal stamper is formed from this substrate by electroplating or the like. In electroforming, a substrate is immersed in an electrolytic solution, and metal ions precipitated by electrolysis are electrodeposited on the surface of the substrate. According to electroplating, the uneven structure of the substrate can be reproduced almost faithfully, and a stamper as a duplicate plate having a thickness of 1 μm or less can be formed.

Since electroforming is a technique for electrodepositing metal ions on the surface of a substrate as described above, the substrate needs to have electrical conductivity. Since photosensitive resists usually do not have electrical conductivity, it is necessary to form a metal thin film on the surface of the photosensitive resist by sputtering, vacuum deposition, etc. before performing electroforming on the substrate. ..

Next, using the metal stamper formed by electroplating as the original plate, the fine uneven structure of the original plate is transferred to the material for forming the support layer. When transferring the uneven structure, first, a base material formed of polyethylene terephthalate (PET), polycarbonate (PC) or the like is prepared, and a thermoplastic resin or a photocurable resin is applied to one surface of the base material. Then, in a state where the metal stamper is pressed against the surface of the resin coated on the base material, heat or light is applied to cure the resin, and then the metal stamper is released from the resin.

As the transfer method, a Step & Repeat method, a Roll to Roll method, or the like can be used. In the Step & Repeat method, the stamper and the resin are arranged in parallel, and the entire surface of the stamper is pressed against the resin at once. Therefore, if the area of the stamper pressed against the resin is large, it becomes difficult to apply pressure uniformly to the entire stamper, and air bubbles are likely to enter between the stamper and the resin.

On the other hand, in the Roll to Roll method, the stamper is wound around a metal roll, and the resin is pressed by linear pressure while rotating the roll. Therefore, the pressure is uniformly applied to the resin as compared with the Step & Repeat method. You can call. In the Roll to Roll method, the uneven structure can be continuously transferred to the resin sheet by repeatedly rotating the roll. Therefore, the Roll to Roll method is suitable for mass production.

As described above, according to the display body and one embodiment of the article, the effects listed below can be obtained.
(1) The wavelength of the light emitted from the first layer element in the observation direction OD and the wavelength of the light emitted from the second layer element in the observation direction OD are different from each other. Therefore, as compared with the configuration in which the wavelength of the light emitted from one fine particle layer in the observation direction OD is uniform, the types of light emitted from the fine particle layer at the wavelength can be increased, and as a result, the display body can be displayed. It is possible to enhance the design of the image to be displayed.

(2) By forming the fine particle layer following the surface of the support layer, it is possible to form a first layer element and a second layer element in which the first distance D1 and the second distance D2 are different from each other.

(3) According to the configuration in which the facing direction of the particle arrangement surface is different between the first layer element and the second layer element, the particle arrangement surface and the direction of the light emitted from the particle arrangement surface are formed. The angles can be different. As a result, the wavelength of the light emitted from the first layer element and the wavelength of the light emitted from the second layer element can be made different.

(4) According to the configuration in which each layer element includes a plurality of fine particle array surfaces, the intensity of the diffracted light emitted from each layer element can be increased as compared with the configuration in which each layer element contains only one fine particle array surface. ..

(5) The expanding two-dimensional direction of the first layer element 62a and the expanding two-dimensional direction of the second layer element 62b intersect each other, and in the first layer element 62a, the expanding two-dimensional direction of the first layer element 62a and the particle arrangement. The two-dimensional direction in which the surface 62s1 spreads is parallel, and in the second layer element 62b, the two-dimensional direction in which the second layer element 62b spreads and the two-dimensional direction in which the particle arrangement surface 62s2 spreads may intersect. According to such a configuration, the angle formed by the first layer element 62a and the second layer element 62b, the particle arrangement surface 62s1 included in the first layer element 62a, and the particle arrangement surface 62s2 included in the second layer element 62b are formed. The angle of formation can be different.

(6) When the average particle size of the plurality of fine particles is 0.1 μm or more and 1 μm or less, the wavelength of the primary diffracted light or the secondary diffracted light emitted from the fine particle layer is likely to be included in the visible light region.

(7) If the period in which the layer elements are lined up is 1 μm or more and the area of the layer elements is 2 μm square or more when viewed from the direction orthogonal to the two-dimensional direction in which the layer elements spread, each layer element has a structural color. As many fine particles as large enough to emit the light can be arranged in a number capable of producing a structural color.

(8) When the difference between the refractive index of the fine particles 52 g and the refractive index of the coating layer 53 is 0.02 or more and 0.7 or less, the amount of diffracted light emitted by the display body 50 is large enough to be visually observed. It becomes easy to become the amount of light.

(9) According to the configuration in which the plurality of first pixels 52p1 include the first layer element 52a, a predetermined image is formed by the set of light emitted from the first layer element 52a included in the plurality of first pixels 52p1. can do.

The above-described embodiment can be modified as appropriate and implemented as follows.
-By having different curvatures between the first layer element and the second layer element, at least one of (b) the two-dimensional direction in which the layer element spreads and (c) the two-dimensional direction in which the particle arrangement plane spreads becomes , The first layer element and the second layer element may have different configurations. A surface having a curvature, that is, a curved surface is a plurality of surfaces capable of emitting a structural color, and is a set of a plurality of surfaces capable of emitting different structural colors. Then, among the faces having different curvatures, the plurality of faces constituting each face are different.

According to the above configuration, the following effects can be obtained.
(10) Due to the difference between the curvature of the first layer element and the curvature of the second layer element, the two-dimensional direction in which the layer element spreads and the particle arrangement plane spread between the first layer element and the second layer element. At least one of the two-dimensional directions can be different, and as a result, the wavelength of the light emitted by the first layer element and the wavelength of the light emitted by the second layer element can be different.

In the display body 60 described above with reference to FIG. 6, the direction in which the first layer element 62a faces and the direction in which the second layer element 62b faces are different from each other, while the inclination angle of the first layer element 62a. α and the inclination angle β of the second layer element 62b may have the same magnitude as each other. Even with such a configuration, if the first distance D1 and the second distance D2 are different because the two-dimensional directions in which the particle arrangement planes spread are different between the first layer element 62a and the second layer element 62b. , The effect according to (1) described above can be obtained.

-As the convex portion included in the support layer, a convex portion having a triangular shape is illustrated in the cross section along the thickness direction of the display body, but the convex portion is, for example, a semicircle in the cross section along the thickness direction of the display body. It may have other shapes such as a shape, an elliptical shape, and a rectangular shape. In short, the support layer is formed between the first layer element and the second layer element located along the surface of the support layer, (b) the two-dimensional direction in which the layer element spreads, and (c) the particle arrangement surface. It suffices to have a shape capable of making the first distance D1 and the second distance D2 different by making at least one of the spreading two-dimensional directions different.

The display body 50 including the plurality of pixels 52p is not limited to the above-mentioned characters including the alphabet, and may be configured to display any image such as numbers, symbols, and figures. It may be configured to display two or more images.

-The article having a display body may be various cards other than IC cards, magnetic cards, wireless cards, and other cards such as ID (identification) cards. Alternatively, the article may be a security such as a gift certificate, a banknote, or a high-class item such as an art piece. Alternatively, the article may be a tag attached to an item that should be confirmed to be genuine, a package that houses the item that should be confirmed to be genuine, or a package of the package. It may be a part.

10,50,60,70,90 ... Display body, 11,101 ... Base material, 12,51,61,71,81,82,83,91 ... Support layer, 12S, 51S, 61S, 71S, 81S, 82S , 91S ... Surface, 13, 20, 52, 62, 72, 92 ... Fine particle layer, 13a, 52a, 62a, 72a ... First layer element, 13b, 52b, 62b, 72b ... Second layer element, 13g, 21, 52g, 62g, 72g ... Fine particles, 13s, 22, 52s, 62s1, 62s2, 72s ... Particle array plane, 30 ... Face-centered cubic lattice, 31,41 ... First array plane, 32,42 ... Second array plane, 40 ... Body-centered cubic lattice, 51S1,61S1,71S1,81S1,82S1,91S1 ... 1st support surface, 51S2, 61S2, 71S2, 81S2, 82S2, 91S2 ... 2nd support surface, 52p ... pixel, 52p1 ... 1st pixel, 52p2 ... 2nd pixel, 53 ... Covering layer, 72t ... Top, 81a, 82a, 91a ... Convex part, 83a ... 1st region, 83a1 ... 1st convex part, 83b ... 2nd region, 83b1 ... 2nd convex part, 83c ... 3rd region, 83c1 ... 3rd convex portion, 100 ... IC card, 102 ... IC chip.

Claims (10)

It is provided with a fine particle layer containing a plurality of fine particles constituting a particle arrangement surface for emitting a structural color.
The fine particle layer is
The first layer element having the first distance as the distance between the particle arrangement planes in the observation direction,
A second layer element having a second distance as the distance between the particle array planes in the observation direction,
Including
By (b) at least one of the two-dimensional directions in which the layer elements spread and (c) the two-dimensional directions in which the particle arrangement plane spreads differ from each other between the first layer element and the second layer element.
A display body in which the first distance and the second distance are different from each other. A support layer including a surface that supports the fine particle layer is further provided.
The surface includes a first support surface that supports the first layer element and a second support surface that supports the second layer element.
The two-dimensional direction in which the first support surface spreads and the two-dimensional direction in which the second support surface spreads are different from each other.
Claim 1 in which at least one of (b) the two-dimensional direction in which the layer element spreads and (c) the two-dimensional direction in which the particle arrangement surface spreads differs between the first layer element and the second layer element. Display body described in. The direction in which the particle arrangement plane in the first layer element faces and
The display body according to claim 1 or 2, wherein the directions in which the particle arrangement planes of the second layer element face are different from each other. Due to the different curvatures of the first layer element and the second layer element,
Claim 1 in which at least one of (b) the two-dimensional direction in which the layer element spreads and (c) the two-dimensional direction in which the particle arrangement surface spreads differs between the first layer element and the second layer element. The display body according to any one of 3 to 3. From claim 1, the plurality of the fine particles contained in the first layer element and the plurality of fine particles contained in the second layer element form a plurality of the particle arrangement planes in the layer element to which each belongs. The display body according to any one of 4. The two-dimensional direction in which the first layer element spreads and the two-dimensional direction in which the second layer element spreads intersect with each other.
In the first layer element, the two-dimensional direction in which the first layer element spreads and the two-dimensional direction in which the particle arrangement surface spreads are parallel.
The display body according to any one of claims 1 to 5, wherein in the second layer element, the spreading two-dimensional direction of the second layer element and the spreading two-dimensional direction of the particle arrangement surface intersect. Each of the fine particles has a spherical shape and has a spherical shape.
The particle size of each of the fine particles is approximately equal to the particle size of all other fine particles.
The display according to any one of claims 1 to 6, wherein the average particle size of the plurality of fine particles is 0.1 μm or more and 1 μm or less. It has light transmittance, fills the space between the plurality of fine particles, and further includes a coating layer covering the fine particle layer.
The display according to any one of claims 1 to 7 , wherein the difference between the refractive index of the fine particles and the refractive index of the coating layer is 0.02 or more and 0.7 or less. The fine particle layer comprises a plurality of the first layer elements.
A plurality of pixels are partitioned in the fine particle layer when viewed from a direction orthogonal to the two-dimensional direction in which the fine particle layer spreads.
The display body according to any one of claims 1 to 8 , wherein the plurality of pixels include the first layer element. An article with a display body
The article in which the display body is the display body according to any one of claims 1 to 9 .