JP2017219738A - Display body and article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display body and an article, in which design property of an image displayed by the display body can be increased.SOLUTION: The display body includes a fine particle layer 13 comprising a plurality of fine particles 13g constituting particle arrangement planes 13s for developing a structural color. The fine particle layer 13 includes a first layer element 13a having a first distance D1 as a distance between the particle arrangement planes 13s in an observation direction OD and a second layer element 13b having a second distance D2 as a distance between the particle arrangement planes 13s in the observation direction. The first distance D1 is different from the second distance D2 by differentiating at least one of (a) a center distance between the fine particles 13g, (b) two-dimensional directions where the layer element extends, (c) two-dimensional directions where the particle arrangement plane 13s extends, and (d) arrangement of fine particles 13g in the particle arrangement plane 13s, between the first layer element 13a and the second layer element 13b.SELECTED DRAWING: Figure 1

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 color emitted by a fine structure of the order of the wavelength of light is a structural color, 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 array 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 layer, the surface in contact with the display layer is a flat surface, and the lattices composed of the fine particles are arranged along the flat surface and stacked on the flat surface (see, for example, Patent Document 1).

JP 2009-223181 A

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

  Therefore, in a display body including such a display layer, an image viewed from a specific observation direction tends to be a monotonous image composed of one color. Therefore, a display body capable of displaying an image with higher designability as an image displayed by the display body is demanded.

  An object of the present invention is to provide a display body and an article that can improve the design of an image displayed on the display body.

  A display for solving the above problem includes a fine particle layer including a plurality of fine particles constituting a particle arrangement surface for emitting a structural color, and the fine particle layer is a first distance as a distance between the particle arrangement surfaces in an observation direction. A first layer element having a distance; and a second layer element having a second distance as a distance between the particle arrangement surfaces in the observation direction. (A) a distance between centers of the fine particles, (b) a two-dimensional direction in which the layer elements spread, (c) a two-dimensional direction in which the particle arrangement surface spreads, and (d) an arrangement of the fine particles in the particle arrangement surface. At least one of the first layer element and the second layer element is different from each other, whereby the first distance and the second distance are different from each other.

  An article for solving the above problems is an article having a display body, and the display body is the display body.

  According to the above configuration, the wavelength of light emitted from the first layer element in the observation direction is different from the wavelength of light emitted from the second layer element in the observation direction. Therefore, compared with the configuration in which the wavelength of light emitted from one fine particle layer in the observation direction is uniform, the number of types of light emitted from the fine particle layer can be increased. The design property in the image to be performed can be improved.

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

  According to the above configuration, the first layer element and the second layer element having the first distance and the second distance different from each other can be formed by forming the fine particle layer along the surface of the support layer. .

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

  According to the above configuration, since the direction in which the particle arrangement surface faces is different between the first layer element and the second layer element, the particle arrangement surface and the direction of light emitted from the particle arrangement surface are formed. The angle can be varied. Thereby, the wavelength of the light emitted from the first layer element can be made different from the wavelength of the light emitted from the second layer element.

  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 extends, and (c) the particle arrangement surface expands. At least one of the two-dimensional directions may be different between the first layer element and the second layer element.

  According to the above configuration, 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 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 made 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 plurality of fine particles included in the first layer element and the plurality of fine particles included in the second layer element constitute a plurality of particle arrangement surfaces in the layer element to which each belongs. Preferably it is.

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

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

  According to the above configuration, 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 above display, each of the fine particles has a spherical shape, and the particle diameter of each of the fine particles is substantially equal to the particle diameter of all the other fine particles, and the average particle diameter 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, a two-dimensional direction in which the first layer element extends is equal to a two-dimensional direction in which the second layer element extends, the fine particle layer includes a plurality of layer elements, and the plurality of layer elements include In the fine particle layer, the plurality of layer elements are arranged along one direction, and the arrangement period of the layer elements is 1 μm or more, and the layer includes the first layer element and the second layer element. When viewed from a direction orthogonal to the two-dimensional direction in which the elements spread, the area of the layer elements may be 2 μm square or more.

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

  In the above display body, the display body has light transmittance, fills 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: 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 is likely to be large enough to allow visual observation.

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

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

  ADVANTAGE OF THE INVENTION According to this invention, the designability in the image which a display body displays can be improved.

The fragmentary sectional view which shows the partial cross section structure of the display body in one Embodiment of the display body which actualized this invention. The schematic diagram for demonstrating the diffraction of the light in a fine particle layer. The perspective view which shows an example of the arrangement | sequence of the microparticles | fine-particles in a microparticle layer. The perspective view which shows an example of the arrangement | sequence of the microparticles | fine-particles in a microparticle layer. The fragmentary sectional view which shows the partial cross-section in an example of a display body. The fragmentary sectional view which shows the partial cross-section in an example of a display body. The fragmentary sectional view which shows the partial cross-section in an example of a display body. The fragmentary sectional view which shows the partial cross-section in an example of a support layer. The fragmentary sectional view which shows the partial cross-section in an example of a support layer. The fragmentary sectional view which shows the partial cross-section in an example of a support layer. The fragmentary sectional view which shows the partial cross-section in an example of a display body. The fragmentary sectional view which shows the partial cross-section in other structure of a fine particle layer. The top view which shows the planar structure which looked at the display body from the direction orthogonal to the two-dimensional direction which a fine particle layer spreads. The top view which shows the planar structure of one Embodiment which actualized the articles | goods in this invention.

  With reference to FIG. 1 to FIG. 14, an embodiment in which a display body and an article of the present invention are embodied will be described.

[Configuration of the display body]
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 are light transmissive.

  In the display body 10, the fine particle layer 13 includes a plurality of fine particles 13g constituting a 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. Have 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 rows is different between the first layer element 13a and the second layer element 13b. Among 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.

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

  Note that the distance between the display 10 and the observation point, which is the position of the observer's viewpoint, is significantly greater 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 regarded as being substantially parallel to each other. In each part of the entire display body 10 as well as between the first layer element 13a and the second layer element 13b, the observation directions OD with respect to each part can be regarded as being parallel to each other.

  According to such a display body 10, the wavelength of light emitted from the first layer element 13a in the observation direction OD is different from the wavelength of light emitted from the second layer element 13b in the observation direction. Therefore, compared with a configuration in which the wavelength of light emitted from one particle layer 13 in the observation direction OD is uniform, the types of wavelengths of light emitted from the particle layer 13 can be increased. The designability of the image displayed by the body 10 can be improved.

  The display 10 may be observed from the direction facing the fine particle layer 13 or from the direction facing the substrate 11. In the fine particle layer 13, a layer composed of a plurality of particles arranged in one particle arrangement surface is a unit layer. In the fine particle layer 13, the plurality of fine particles 13 g are arranged most periodically in the first layer that is a unit layer in contact with the surface 12 </ b> S of the support layer 12. The periodicity in the 13 g array tends to be disturbed.

  In particular, when the surface 12S of the support layer 12 includes two or more portions, the two-dimensional directions in which each portion spreads are different from each other, and two portions in which the two-dimensional directions that spread are different from each other are adjacent to each other, the two portions It is considered that a region in which the periodicity in the arrangement is not maintained is likely to be generated because the fine particles arranged along different directions are mixed at the boundary. 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 FIG. 2 to FIG. 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 light diffraction 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 array 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 arranged in a predetermined cycle, when incident light IL enters the fine particle layer 20, light diffraction that satisfies the following expression (1) occurs from Bragg's law.

  In equation (1), m is the diffraction order, 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 surfaces, that is, the distance between the array surfaces, θ Is an incident angle of the incident light IL. The colloidal crystal is a structure in which the fine particles 21 are arranged in a three-dimensional cycle and can exhibit a structural color.

The refractive index n can be approximately obtained from the volume average refractive index of the fine particles 21 and the medium filling the space between the fine particles 21. When the filling 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.

  Equation (1) is expressed in the direction of the angle θ when each of the incident light IL1 and the incident light IL2 is incident on the particle array surface 22 in which the fine particles 21 are arrayed at the distance d between the array surfaces. Means that the optical path difference 2ndsinθ between the incident lights IL1 and IL2 has a wavelength λ that satisfies the equation (1). Further, if the expression (1) is viewed from another viewpoint, even if the incident light is incident from the same angle θ, the distance d between the array planes is different, so that the emitted light strengthened by the diffraction at the fine particle layer 20 is increased. It can be seen that the wavelength λ changes.

  In FIG. 2, incident light that enters the fine particle layer 20 at an angle θ is emitted at an angle θ that is symmetrical to the incident light with respect to a 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 degree, in other words, the particle arrangement surface 22 is horizontal. However, as in the configuration described above with reference to FIG. In the configuration including the inclined surface, the normal direction on the inclined surface is shifted from the normal direction with respect to the surface extending along the horizontal direction by the inclination angle. Therefore, in the portions having different inclinations on the surface, sin θ in the equation (1) is different from each other, thereby causing a difference in the wavelength λ of light emitted from each portion. As a result, when the display body 10 is observed from a specific angle, in other words, from a specific observation direction, different colors can be observed locally.

  The average particle diameter 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 equation (1), assuming that the diffraction order m is 1 and the refractive index n is 1, assuming that the incident angle θ of light is 90 degrees, the wavelength λ of the diffracted light is the distance between the array planes d. Doubled.

  As the colloidal crystals described above, close-packed opal crystals and non-close-packed colloidal crystals are known. Among these, in the opal crystal, the distance d between the arrangement planes coincides with the average particle diameter 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. Easy to do. Even when the average particle size r of the fine particles 21 is outside this range, when diffracted light having a diffraction order m of 2 is observed or when the angle at which the opal crystal is observed is changed, the light is emitted from the opal crystal. Can be visually recognized.

  FIG. 3 shows a schematic structure of a face-centered cubic lattice, and FIG. 4 shows a schematic structure of a body-centered cubic lattice. 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-described equation (1), the wavelength λ of light emitted from the fine particle layer at a specific angle θ changes according to the inter-array surface distance d. The face-centered cubic lattice 30 shown in FIG. 3 shows a first array surface 31 and a second array surface 32 as examples of particle array surfaces that can be set in the unit cell. Further, the body-centered cubic lattice 40 shown in FIG. 4 also shows a first array surface 41 and a second array surface 42 as examples of particle array surfaces that can be set in the unit lattice.

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

  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).

  As described above, when the method of setting the particle arrangement surface in one unit cell is changed, the distance d between the arrangement surfaces is changed, and the structure of the unit cell is different. In other words, the arrangement of fine particles in the particle arrangement surface is changed. The distance d between the arrangement surfaces also varies depending on the difference. In the above-described formula (1), when the diffraction order m, the refractive index n, and the incident angle θ of light are constant, the wavelength λ is proportional to the inter-array surface distance d.

  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 arrangement surface 31 is 700 nm, the wavelength of the light reflected by the second arrangement 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 is reflected by each particle array surface. The color of the light is very different.

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

  As described above, the opal crystal and the non-close-packed colloidal crystal have different distances d between the arrangement planes, but the difference between the distances d between the arrangement planes in the two crystals in this way is the lattice constant of 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 formula (7) holds for the face-centered cubic structure and the formula (8) holds for the body-centered cubic structure between the average particle diameter r, the lattice constant a, and the fine particle filling factor φ. Yes.

[Number of unit layers in 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 constitute a plurality of particle arrangement surfaces.

  Further, in the fine particle layer 13 described above with reference to FIG. 1, a plurality of fine particles 13g included in the first layer element 13a and a plurality of fine particles 13g included in the second layer element 13b belong to the respective layers. It is preferable that the element constitutes a plurality of particle arrangement surfaces 13s. Since the intensity of the diffracted light increases as the number of particle array surfaces 13s increases, the visibility of the structural color improves as the number of particle array surfaces 13s increases.

  In addition, if the fine particle layer 20 is configured to include a first portion including a predetermined number of unit layers and a second portion including a number of unit layers different from the first portion, the first portion It is possible to add a shade between the structural color at and the structural color at the second portion. Thereby, compared with the structure which cannot express such a light and shade, the designability in the image which a display body expresses increases.

  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 of the surface and the position of the other end may be increased in the cross section along the thickness direction of the display body. Alternatively, when 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 also be increased by making the particle size of the fine particles 21 smaller.

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

[First embodiment]
As shown in FIG. 5, the fine particle layer 52 includes a first layer element 52a and a second layer element 52b. Between the first layer element 52a and the second layer element 52b, a two-dimensional direction in which the layer element spreads out. Are different from each other. Further, the two-dimensional direction in which the particle arrangement surface 52s of each layer element spreads is 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 51 </ b> S that supports the fine particle layer 52. The surface 51S includes a first support surface 51S1 and a second support surface 51S2 that support the first layer element 52a. The two-dimensional direction in which the first support surface 51S1 extends and the two-dimensional direction in which the second support surface 51S2 extends. Are different from each other.

  When the substrate 11 is arranged along the horizontal direction, the angle at which the surface 51S is inclined with respect to the horizontal direction, that is, the angle formed by the horizontal direction and the surface 51S is the inclination angle. Of the surface 51S, the inclination angle α in the first support surface 51S1 and the inclination angle β in 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 52g are arranged at an equal period along the particle arrangement surface 52s. The array surface distance da in the first layer element 52a and the array surface distance db in the second layer element 52b are equal to each other.

  The two-dimensional direction in which the first support surface 51S1 extends, the two-dimensional direction in which the second support surface 51S2 extends, in other words, the direction of the normal to the first support surface 51S1 and the direction of the normal 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 to 52a is different from the direction of the normal to the second layer element 52b.

  Here, the light emitted from the first layer element 52a in the predetermined observation direction OD is the emitted light EL1, and the light emitted from the second layer element 52b in the same direction as the emitted light EL1 is the emitted light EL2. is there. The light for emitting the emitted light EL1 is the incident light IL1, the light for emitting the emitted 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 enters 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 emitted light EL1 and the wavelength λ2 of the emitted light EL2 are different from each other. As a result, the color of light emitted from the first layer element 52a and the color of light emitted from 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 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 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, with respect to the inclination angle α, the reflected light from the fine particle layer 52 can be obtained when the following expression (10) holds.

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

  Note that when the inclination of the display body 50 with respect to the horizontal direction is changed to an angle other than 45 degrees or when light of higher diffraction orders is observed, 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-described range. Even with such a configuration, it is possible to observe the emitted light EL1 from the first layer element 52a and the emitted light EL2 from the second layer element 52b.

[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 direction in which the two-dimensional direction in which the first layer element 62a extends and the two-dimensional direction in which the second layer element 52b extends intersect each other, and the direction in which the particle arrangement surface 62s1 of the first layer element 62a faces, and the second layer element The direction in which the particle array surface 62s2 in 62b faces is different from each other.

  The direction in which the particle arrangement surface faces is the direction in which the particle arrangement surface faces. Here, the incident angle of the incident light with respect to the fine particle layer 62 has a predetermined range. Of the incident light, the light having the predetermined incident angle is reflected the highest and out of the light emitted from the fine particle layer 62. The intensity of the light emitted at the same angle as the incident angle with the highest incident light intensity is the highest.

  The observer of the display body 60 visually recognizes light in which emitted light having the highest intensity and other emitted light are mixed. 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 same 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 different so 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 differ by about 20 nm to 50 nm. The facing direction and the direction in which the particle arrangement surface 62s2 of the second layer element 62b faces are preferably different.

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

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

  On the surface 61S of the support layer 61, the direction facing the first support surface 61S1 and the direction facing 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, the fine particles 62g are arranged in an equal cycle in the direction along the surface 61S. However, in emitting light toward the predetermined observation direction OD, when the incident light IL1 is incident on the first layer element 62a, the particle array surface 62s1 along the first support surface 61S1 is a reflection surface, When the incident light IL2 is incident on the second layer element 62b, the particle array surface 62s2 that intersects the second support surface 61S2 is a reflection surface.

  For this reason, the inter-array surface distance da in the first layer element 62a and the inter-array surface distance 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 is different between the first support surface 61S1 and the second support surface 61S2 because the facing direction and the inclination angle of each surface are different from each other. λ1 and the wavelength λ2 of the emitted light EL2 emitted from the second layer element 62b can be made different from each other.

  In the first and second embodiments, the wavelength λ1 of the emitted light EL1 and the wavelength λ2 of the emitted light EL2 are different from each other in one observation direction OD, while the emitted light is different in the other observation directions OD. The fine particle layer may be configured such that the wavelength λ1 of EL1 is equal to the wavelength λ2 of the emitted light EL2. In such a configuration, by changing the observation direction OD, a change in the color of the image displayed by the display body can be made to move and the eye catching effect can be enhanced.

[Third embodiment]
As shown in FIG. 7, in the fine particle layer 72, the distance between the fine particles 72g is the interparticle distance dc. The inter-particle distance dc is different 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 extends is equal to the two-dimensional direction in which the second support surface 71S2 extends, 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 surfaces 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. 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 to the first layer element 72a and the direction of the normal 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 is equal to the incident angle θ2 of the incident light IL2 with respect to the second layer element 72b, the emitted light of the first layer element 72a. EL1 and the emitted light EL2 of the second layer element 72b are emitted in a predetermined observation direction OD that is the same direction.

  As is clear from the above-described formula (1), the wavelength λ1 of the emitted light EL1 and the wavelength λ2 of the emitted light EL2 are determined by the inter-array surface distance d and the light incident angle θ. In the support layer 71 having a predetermined shape, by setting the observation direction with respect to the display body 70, the light emission direction and further the angle θ at which light enters the support layer 71, that is, the fine particle layer 72 are determined. Therefore, Equation (1) can be rewritten as a function of the wavelength λ and the inter-array surface distance d.

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

  Also in such a display body 70, in the fine particle layer 72, the inter-array surface distance da of the first layer element 72a and the inter-array surface distance db of the second layer element 72b are different from each other. Therefore, the wavelength of the light emitted from the first layer element 72a toward the observation direction OD and the wavelength of the light emitted from the second layer element 72b 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. In the support layer 71, the top portion 72t included in the first support surface 71S1 and the second support are provided. The distance between the tops 72t included in the surface 71S2 is the top-to-top distance p. In order to suppress the diffracted light from being emitted from the support layer 71, it is preferable that the distance p between the tops is 1 μm or more. The reason why the distance between the tops is preferably 1 μm or more will be described below.

  As an appearance condition of the diffracted light by the diffraction grating, Expression (11) is known.

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

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

  However, in actuality, the angle changes to an angle different from the incident angle θ of 90 ° with respect to the support layer 71, or first-order or higher-order diffracted light is observed. For example, assuming that the incident angle θ of light is 15 degrees and the diffraction order m is 2, the inter-top distance 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 p between the tops is 6 μm or more.

  The fine particle layer 72 includes a plurality of layer elements, and the plurality of layer elements includes 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 arrangement period of the layer elements is 1 μm or more. When viewed from a direction orthogonal to the two-dimensional direction in which the layer element extends, the area of the layer element is preferably 2 μm square or more.

  According to such a display body 70, in each layer element, the fine particles 72g having such a size that can emit light having a structural color can be arranged in a number that can generate a structural color. .

[Example of support layer shape]
An example of the shape of the support layer will be described with reference to FIGS. Hereinafter, four examples of support layers having different shapes will be described. In FIG. 11, hatching of the support layer is omitted for the sake of convenience of illustrating light emitted outside the display body through 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. Between the first support surface 81S1 and the second support surface 81S2, the inclination angles with respect to the horizontal direction are equal to each other, but the two-dimensional direction in which each surface spreads, that is, the direction in which each surface faces, is 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 triangle shape. In the cross section of each convex portion 81a, the lengths of 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 the respective sides are equal to each other.

  In the support layer 81, the first support surface 81 </ b> S <b> 1 and the second support surface 81 </ b> S <b> 2 pass through the top of the convex portion 81 a and in a direction 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 a symmetry axis, 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 symmetry axis. When the fine particles arranged on each surface are arranged symmetrically with respect to the symmetry axis, 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, the second support surface 81S2 The change in structural color observed in the observation direction is symmetric between when the display body is tilted in the direction in which the angle formed between 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 expand are different from each other, more specifically, the inclination angles with respect to the horizontal direction are different from each other, and the directions in which the surfaces face each other 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 horizontally between two sides forming the top portion. The inclination angles with respect to the directions are different from each other.

  In the display body including such a 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 axis is larger than the axis extending in the direction orthogonal to the horizontal direction, The change in the structural color observed in the observation direction between when the display body is tilted in the direction in which the angle formed by the support surface 82S2 and the axis is large is untargeted. In addition, since the viewing area where the reflected light is observed also varies depending on the tilt angle of the surface 82S, even if the display body is tilted in one direction even when tilted by the same angle, the structural color is observed, When the display body is tilted in another direction, a difference is generated between the region where the structural color is observed.

  Thus, since the viewing area of the light emitted from the fine particle layer and the wavelength of the light can be changed according to the shape of the surface 82S of the support layer 82, the shape of the surface 82S of the support layer 82 is used. The display body can be configured 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, It is also possible to configure the display body so as to display the second pattern by the second support surface 82S2. Furthermore, the first pattern is displayed in red by setting the structural color emitted by the first layer element to red, and the second pattern is displayed in green by setting the structural color emitted by the second layer element to green. It is also possible to configure the display body as described above.

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

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

  However, if there is no line that emits one color at a resolution that the observer can visually recognize at the distance at which the observer observes the display body, the observer will recognize the color difference between the areas. Can not. Therefore, for example, when it is desired to express completely different colors such as red and green in adjacent areas, it is necessary to arrange a plurality of fine structures for emitting each color so as to form an area having a predetermined size. There is.

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

[Fourth shape]
As shown in FIG. 11, in the display body 90, the surface 91S of the support layer 91 includes a first support surface 91S1 and a second support surface 91S2, and between the first support surface 91S1 and the second support surface 91S2. The directions of the faces are different from each other. In the cross section along the thickness direction of the display body 90, one convex portion 91a is defined 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 in the direction in which the convex portions 91a are arranged. And a curved surface. 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 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 the top. In the direction in which the convex portions 91a are arranged, the curved surface of the first support surface 91S1 included in the 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 serve as the bottom portion. Forming.

  In the display body 90 including such a support layer 91, the incident light IL incident on the inclined surface of the second support surface 91 </ b> S <b> 2 out of the light incident on the display body 90 from the direction orthogonal to the direction in which the base material spreads is adjacent to the convex portion. Reflected by the fine particle layer 92 toward the slope of the first support surface 91S1 of the 91a. The light incident on the inclined surface of the first support surface 91S1 is emitted as the emitted light EL in the light incident direction by the fine particle layer 92. On the other hand, the incident light IL incident on the bottom of the support layer 91 is reflected only once at the fine particle layer 92 and is emitted as the emitted light EL in the direction in which the light is incident.

  As described above, in the fine particle layer 92, the light reflected at the portion in contact with the bottom of the support layer 91 and the light reflected at the portion in contact with the slope of the first support surface 91S1 Therefore, the incident angles of light are different from each other. Therefore, when the interference condition changes between the two parts of the fine particle layer 92, each part emits a different structural color. The two structural colors are different from each other microscopically, but 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.

[Vertical angle in the 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 the display body is observed, that is, the light reflected by the fine particle layer formed on the support surface is observed. The angle range of incident light that is emitted toward a person is narrower as the apex angle of the convex portion is smaller. In other words, the smaller the apex angle of the convex portion is, the more the viewing area is limited.

  Furthermore, even when the apex angles are equal, the angle range of the incident light described above varies depending on the shape of the convex portion in the cross section along the thickness direction of the display body. For example, in the prism, when the cross-sectional shape is a right triangle, the length of the slope is the largest, and in this case, the region where the reflected light is observed on the observer side is the largest. Therefore, if you want to increase the area where the diffracted light can be visually recognized on the display body, that is, if you want to reduce the area that appears dark in the display body and make the entire display body appear brighter, the support layer will It is preferable to include a large convex part.

  As the apex angle increases, the lower limit value that can be taken by the light incident angle θ in the equation (1) becomes smaller. In addition, 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 inter-array surface distance d in the fine particle layer is set to a predetermined value. In order to do this, it is necessary to select the optimum material.

  For example, when it is desired to obtain reflected light having a wavelength of 600 nm when the incident angle θ of light, that is, the reflected angle θ of light is 30 degrees, the refractive index n and the array are obtained from the equation (1). A value obtained by multiplying the inter-plane distance d is 600. When the fine particle layer is composed of a close-packed colloidal crystal, that is, an opal crystal, the refractive index n is the refractive index of the medium, and the inter-array surface distance d 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 diameter of 600 nm, a combination of a medium having a refractive index of 1.2 and fine particles having a particle diameter of 500 nm, and a refractive index of 1.5. Any combination of the medium and the fine particles having a particle diameter of 400 nm may be selected. Thereby, 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 a non-close-packed colloidal crystal, as described above, the refractive index n and the inter-array surface distance d take into account the filling rate and electrostatic repulsion. You have to ask.

[Other composition of fine particle layer]
With reference to FIG. 12, another configuration of the fine particle layer will be described. In addition, below, the fine particle layer demonstrated previously with reference to FIG. 5 among each form of the fine particle layer mentioned above is demonstrated. Note that the configuration described below can also be applied to fine particle layers having other forms.

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

  Among the colloidal crystals described above, in the non-close-packed colloidal crystal, the fine particles 52g 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 52g is weaker than that of the opal crystal, and the arrangement period of the fine particles in the fine particle layer 52 may be disturbed by vibrations 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 arrangement period of the fine particles 52g, it is preferable to fix the crystal structure of the colloidal crystal by the coating layer 53.

  A material for forming the coating layer 53 is, for example, a polymer gel fixed by irradiation with ultraviolet rays. Examples of the polymer gel include polyacrylamide, gelatin, and polyethylene glycol. In addition, 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 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 refractive index between them is small, the amount of light diffracted by the fine particles 52g in the coating layer 53 is small, so that it is difficult to visually observe the structural color. Therefore, the difference in refractive index between these is preferably 0.02 or more.

  On the other hand, among resins that are generally available, the refractive index of a 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 the fine particles 52g is the refractive index of air. Assuming that the refractive index is 1.0, the difference between the refractive index of the fine particles 52g 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 polystyrene fine particles that can be used as the fine particles 52g is 1.4 or more, the difference between the refractive index of the fine particles 52g and the refractive index of the coating layer 53 is substantially the same. The maximum is about 0.3. For this reason, when the coating layer 53 covering the fine particles 52g is formed, the difference between the refractive index of the fine particles 52g and the refractive index of the coating layer 53 is 0.02 or more and 0.7 or less. And the forming material of the coating layer 53 may be selected.

[Planar structure of display]
The planar structure of the display body will be described with reference to FIG. In addition, below, the display body demonstrated previously with reference to FIG. 5 among each form of the display body mentioned above is demonstrated. Note that the configuration described below can also be applied to display bodies having other forms.

  As shown in FIG. 13, when viewed from a direction orthogonal to the two-dimensional direction in which the fine particle layer 52 spreads, the fine particle layer 52 has a plurality of pixels 52p. The display body 50 including the fine particle layer 52 has a rectangular shape when viewed from the direction orthogonal to the two-dimensional direction in which the fine particle layer 52 extends. The fine particle layer 52 includes 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 the other pixels 52p are partitioned. The plurality of pixels 52p are arranged along one direction and a direction orthogonal to the 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 includes a plurality of first pixels 52p1 and a plurality of second pixels 52p2. Among 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, since the color emitted from the first pixel 52p1 and the color emitted from the second pixel 52p2 are different from each other when viewed from a specific observation direction, the image displayed on the display body 50 is composed of the plurality of first pixels 52p1. It is the image comprised from the part to display, and the part which the some 2nd pixel 52p2 displays.

  When viewed from the direction orthogonal to the two-dimensional direction in which the fine particle layer 52 extends, among 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 images. 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 alphabets “O” and “K” and their backgrounds.

[Goods]
An example of an article having the display body 10 will be described with reference to FIG. Hereinafter, an IC card will be described as an example of an 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 substrate 101 when viewed from a direction orthogonal to the direction in which the substrate 101 spreads.

[Method of forming fine particle layer]
A method for forming a colloidal crystal 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 production method for opal crystals, a method is known that utilizes the phenomenon of self-assembly in the process of aggregation of fine particles. As one of the methods, a sedimentation method is known. In the sedimentation method, a plurality of colloidal fine particles having a small surface charge and a uniform particle diameter are dispersed in a dispersion medium, and the fine particles are settled using gravity. It is a method of arranging or arranging a dispersion medium by evaporating.

  In the sedimentation method, when the particle size of the fine particles is 500 nm or less, and when the specific gravity of the colloidal fine particles and the specific gravity of the dispersion medium are about the same, the dispersed state of the fine particles becomes an equilibrium state, and the colloidal fine particles are not crystallized. . Thus, in the sedimentation method, various factors such as the particle size of the colloidal particles, the specific gravity difference between the colloidal 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 particles. Therefore, it is difficult to determine the optimum conditions.

  As other methods, methods utilizing physical limitations are known, and these methods include advection accumulation methods using capillary forces acting between colloidal fine particles at the gas-liquid interface, lifting methods developed from advection accumulation methods, And electrophoresis method etc. are mentioned. In opal crystals, since the fine particles are arranged in contact with each other, if the particle size of the colloidal fine particles used to form the colloidal crystal varies, the alignment of the colloidal fine particles is disturbed and the dispersion medium is dried. During the process, cracks are likely to occur in the colloidal crystal.

  On the other hand, a non-close-packed colloidal crystal is one in which colloidal fine particles having a 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 are crystallized in a state of being separated from each other, so that the disorder of the arrangement in the colloidal fine particles due to the variation in the particle diameter is alleviated. Such crystals are known as charged colloidal crystals, but when the repulsive force between the colloidal particles is weak, the colloidal particles are randomly distributed, so the repulsive force is sufficient to arrange the colloidal particles periodically. Must be bigger.

  In order to increase the electrostatic repulsion between the colloidal particles, it is effective to increase the concentration, ion concentration, and pH of the colloidal 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 only a part of the silanol groups is dissociated in pure water. Is small. Therefore, when an alkali such as sodium hydroxide (NaOH) is added to the dispersion medium, the number of charges increases as the dissociation of silanol groups proceeds.

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 polymethyl methacrylate (PMMA) fine particles. In addition, since silica, polystyrene, and polymethylmethacrylate have a relatively large specific gravity, these materials are effective for producing a close-packed colloidal crystal by a precipitation method.

[Method of forming support layer]
The support layer having each shape described above can be formed using the following method.
When forming the support layer, first, an original plate for forming the support layer is formed. For example, a photolithography method can be used for forming the original plate. In forming an original plate using a photolithography 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 using an electron beam or a laser, and the exposed photosensitive resist 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 during development or a negative resist in which the unexposed portion of the photosensitive resist dissolves. May be. Then, a resist pattern may be designed according to the selected resist material.

  A substrate having a resist pattern can be used 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 mass production stampers. Therefore, a metal stamper is formed from this substrate using electroforming or the like. In electroforming, a substrate is immersed in an electrolytic solution, and metal ions deposited by electrolysis are electrodeposited on the surface of the substrate. According to electrocasting, the concavo-convex 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.

  In addition, since electrocasting is a technique in which metal ions are electrodeposited on the surface of the substrate as described above, the substrate needs to have electrical conductivity. Since the photosensitive resist usually does not have electrical conductivity, it is necessary to form a metal thin film on the surface of the photosensitive resist by sputtering, vacuum deposition, or the like before electroforming the substrate. .

  Next, using the metal stamper formed by electroforming as a master, the fine uneven structure of the master is transferred to the material for forming the support layer. When transferring the concavo-convex structure, first, a base material formed from polyethylene terephthalate (PET), polycarbonate (PC), or the like is prepared, and a thermoplastic resin or a photo-curing 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 applied to the substrate, the resin is cured by applying heat or light, 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, a stamper and a resin are arranged in parallel, and the entire surface of the stamper is pressed against the resin at once. For this reason, when the area of the stamper pressed against the resin is large, it is difficult to apply a uniform pressure to the entire stamper, and air bubbles easily enter between the stamper and the resin.

  On the other hand, in the Roll to Roll method, the resin is pressed with linear pressure while rotating the roll in a state where the stamper is wound around the metal roll, so the pressure is uniformly applied to the resin compared to the Step & Repeat method. You can hang it. In the Roll to Roll method, the concavo-convex 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 one embodiment of the display body and the article, the effects listed below can be obtained.
(1) The wavelength of light emitted from the first layer element in the observation direction OD is different from the wavelength of light emitted from the second layer element in the observation direction OD. Therefore, compared with the configuration in which the wavelength of light emitted from one fine particle layer in the observation direction OD is uniform, the types of wavelengths of light emitted from the fine particle layer can be increased. The designability in the image to be displayed can be improved.

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

  (3) According to the configuration in which 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 light emitted from the particle arrangement surface are formed. The angle can be varied. Thereby, the wavelength of the light emitted from the first layer element can be made different from the wavelength of the light emitted from the second layer element.

  (4) According to the configuration in which each layer element includes a plurality of fine particle arrangement surfaces, the intensity of 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 arrangement surface. .

  (5) The two-dimensional direction in which the first layer element 62a extends and the two-dimensional direction in which the second layer element 62b extend intersect each other, and in the first layer element 62a, the two-dimensional direction in which the first layer element 62a extends and the particle arrangement The two-dimensional direction in which the surface 62s1 extends may be parallel, and in the second layer element 62b, the two-dimensional direction in which the second layer element 62b extends may intersect with the two-dimensional direction in which the particle array surface 62s2 extends. 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 as follows. The angle to be formed can be made different.

  (6) If the average particle diameter of the plurality of fine particles is 0.1 μm or more and 1 μm or less, 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.

  (7) If the period of layer elements 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. The fine particles having such a size that the emitted light can be emitted can be arranged in a number capable of generating a structural color.

  (8) If the difference between the refractive index of the fine particles 52g 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 from the display body 50 is large enough to be observed visually. It becomes easy to become light quantity.

  (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 a set of light emitted from the first layer elements 52a included in the plurality of first pixels 52p1. can do.

The embodiment described above can be implemented with appropriate modifications as follows.
The curvature between the first layer element and the second layer element is different from each other, so that 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 is The first layer element and the second layer element may be different from each other. Note that a surface having a curvature, that is, a curved surface, is a plurality of surfaces that can emit structural colors, and is a set of a plurality of surfaces that can emit different structural colors. A plurality of surfaces constituting each surface are different between surfaces having different curvatures.

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 surface spread between the first layer element and the second layer element. At least one of the two-dimensional directions can be made different. As a result, the wavelength of the light emitted from the first layer element can be made different from the wavelength of the light emitted from the second layer element.

  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 be the same size. Even in such a configuration, if the first distance D1 and the second distance D2 are different between the first layer element 62a and the second layer element 62b because the two-dimensional directions in which the particle arrangement surface spreads are different from each other. The effect according to (1) described above can be obtained.

  -As the convex part included in the support layer, the convex part having a triangular shape is exemplified in the cross section along the thickness direction of the display body, but the convex part 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 extends, and (c) the particle arrangement surface. It is only necessary to have a shape that can make the first distance D1 and the second distance D2 different by changing at least one of the two-dimensional directions that spread.

  The display body 50 including the plurality of pixels 52p is not limited to the characters including the alphabets described above, 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 the display body may be other cards such as various cards other than an IC card, a magnetic card, a wireless card, and an ID (identification) card. Alternatively, the article may be a securities such as a gift certificate and banknotes, or may be a luxury item such as a work of art. Alternatively, the article may be a tag attached to an item to be confirmed as an authentic product, a package that contains an item to be verified as an authentic product, or a 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 ... first support surface, 51S2, 61S2, 71S2, 81S2, 82S2, 91S2 ... second support surface, 52p ... pixel, 5 p1 ... first pixel, 52p2 ... second pixel, 53 ... covering layer, 72t ... top, 81a, 82a, 91a ... convex, 83a ... first region, 83a1 ... first convex, 83b ... second region, 83b1 ... 2nd convex part, 83c ... 3rd area | region, 83c1 ... 3rd convex part, 100 ... IC card, 102 ... IC chip.

Claims (11)

A fine particle layer including a plurality of fine particles constituting a particle arrangement surface for emitting a structural color,
The fine particle layer is
A first layer element having a first distance as a distance between particle array surfaces in the observation direction;
A second layer element having a second distance as a distance between the particle arrangement surfaces in the observation direction;
Including
(A) a distance between centers of the fine particles, (b) a two-dimensional direction in which the layer elements spread, (c) a two-dimensional direction in which the particle arrangement surface spreads, and (d) an arrangement of the fine particles in the particle arrangement surface. At least one is different from each other between the first layer element and the second layer element,
The 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;
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 extends and the two-dimensional direction in which the second support surface extends are different from each other,
The at least one of (b) the two-dimensional direction in which the layer element extends, and (c) the two-dimensional direction in which the particle array surface extends differ from each other between the first layer element and the second layer element. Display body described in 1. A direction in which the particle arrangement surface of the first layer element faces;
The display body according to claim 1, wherein directions in which the particle arrangement surfaces of the second layer elements face are different from each other. By different curvatures between the first layer element and the second layer element,
The at least one of (b) the two-dimensional direction in which the layer element extends, and (c) the two-dimensional direction in which the particle array surface extends differ from each other between the first layer element and the second layer element. 4. The display body according to any one of items 1 to 3. The plurality of fine particles included in the first layer element and the plurality of fine particles included in the second layer element constitute a plurality of the particle arrangement surfaces in the layer element to which each belongs. 5. The display body according to any one of 4. A two-dimensional direction in which the first layer element extends and a two-dimensional direction in which the second layer element extends intersect each other;
In the first layer element, the two-dimensional direction in which the first layer element extends and the two-dimensional direction in which the particle array surface extends are parallel,
The display body according to any one of claims 1 to 5, wherein in the second layer element, a two-dimensional direction in which the second layer element extends intersects with a two-dimensional direction in which the particle arrangement surface extends. Each of the fine particles has a spherical shape,
The particle size of each fine particle is substantially equal to the particle size of all the other fine particles,
The display body according to claim 1, wherein an average particle diameter of the plurality of fine particles is 0.1 μm or more and 1 μm or less. A two-dimensional direction in which the first layer element extends and a two-dimensional direction in which the second layer element extends are equal to each other;
The particulate layer comprises a plurality of layer elements;
The plurality of layer elements are composed of the first layer element and the second layer element,
In the fine particle layer, the plurality of layer elements are arranged along one direction,
A period in which the layer elements are arranged is 1 μm or more;
The display body according to claim 7, wherein an area of the layer element is 2 μm square or more as viewed from a direction orthogonal to a two-dimensional direction in which the layer element extends. It has light transmittance, and further includes a coating layer that fills between the plurality of fine particles and covers the fine particle layer,
The display body according to any one of claims 1 to 8, wherein a difference between a refractive index of the fine particles and a refractive index of the coating layer is 0.02 or more and 0.7 or less. The particulate layer comprises a plurality of the first layer elements;
A plurality of pixels are defined in the fine particle layer as seen from a direction orthogonal to the two-dimensional direction in which the fine particle layer spreads,
The display body according to claim 1, wherein the plurality of pixels include the first layer element. An article having a display body,
The said display body is a display body as described in any one of Claim 1 to 10. Goods.