JP2018063305A - Display body and manufacturing method for display body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display body capable of enhancing a function developed by an appearance of the display body, by use of a waveguide mode resonance phenomenon, and a manufacturing method for the display body.SOLUTION: The display body includes a display element, which includes: a first grating region 13 having a first high refractive index part 13a and a first low refractive index part 13b constituting a first sub-wavelength grating; a second grating region 15 having a second high refractive index part 15a and a second low refractive index part 15b constituting a second sub-wavelength grating; a first low refractive index region 12; a second low refractive index region 14; and a third low refractive index region 16. The first sub-wavelength grating and the second sub-wavelength grating have the same grating period. Volume ratios of the high refractive index parts 13a, 15a in the first grating region 13 and the second grating region 15, respectively, are equal to each other. In a view in the direction opposing to the surface of the display body, the first high refractive index part 13a and the second low refractive index part 15b overlap each other, and the second high refractive index part 15a and the first low refractive index part 13b overlap each other.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a display body using structural colors and a method for manufacturing the display body.

  The display body is configured to exhibit a structural color, for example, authentication documents such as passports and licenses, and securities that are difficult to forge, such as securities such as gift certificates and checks. To increase the difficulty of counterfeiting the article. In addition, for example, the display body is provided in an article around us to enhance the design of the article.

  The structural colors represented by the scales of morpho butterflies and the epidermis of iridescent are different from the colors seen due to electronic transitions in molecules like the colors exhibited by pigments. It is a color visually recognized by the action of an optical phenomenon caused by the structure. By using the structural color, forgery and design of an article including a display body are enhanced.

  For example, the structural color due to multilayer film interference is a structural color generated when light in a specific wavelength region reflected at each interface of the multilayer film is intensified by interference, and displays using multilayer film interference are widely known. Yes. However, since the color that the display body exhibits due to multilayer film interference depends on the layer configuration such as the film thickness of each layer in the multilayer film, in the display body using multilayer film interference, for each color that the display body wants to visually recognize, It is necessary to form a multilayer film having a different layer structure. Therefore, since the difference in the manufacturing process of the display body due to the difference in color is large, the versatility is poor, and the manufacturing process of the display body having a plurality of regions exhibiting different colors must be very complicated.

  As a configuration for visually recognizing a structural color by an optical phenomenon different from multilayer interference, an optical device using a waveguide mode resonance phenomenon has been proposed (for example, see Patent Documents 1 and 2). This optical device has a sub-wavelength grating which is a diffraction grating arranged with a period smaller than the wavelength of light. When light is incident on the sub-wavelength grating, the emission of diffracted light to the incident side space is suppressed, while light in a specific wavelength region causes resonance by propagating while being reflected multiple times. A waveguide mode resonance phenomenon occurs in which is strongly emitted as reflected light.

Japanese Patent No. 5023324 JP 2009-25558 A

  When the waveguide mode resonance phenomenon is used for a display body, the higher the intensity of the reflected light emitted from the display body, that is, the higher the wavelength selectivity of the reflected light, the clearer and brighter the color visually recognized on the display body. Therefore, the visibility of the image formed by the display body is improved. As a result, forgery difficulty and design of an article provided with a display body are enhanced, so that the wavelength selectivity of reflected light is preferably higher.

  For example, Patent Document 1 describes a structure in which a plurality of convex portions constituting a sub-wavelength grating are arranged on a substrate as a structure that causes a guided mode resonance phenomenon. However, in order to obtain reflected light excellent in wavelength selectivity with such a structure, as described in Patent Document 1, the substrate is formed from synthetic quartz and the convex portion is formed from silicon. It is desirable to secure a large difference in refractive index between the convex portion and the convex portion to reduce loss due to multiple reflection of light propagating through the sub-wavelength grating region. For that purpose, since it is necessary to use a SOQ (Silicon on Quartz) substrate in which single crystal Si is formed on a substrate made of synthetic quartz, the manufacturing cost increases.

  On the other hand, Patent Document 2 has a structure in which a waveguide layer made of a material having a refractive index higher than that of the material constituting the substrate is located between the substrate and the convex portions constituting the sub-wavelength grating. Have been described. According to such a structure, even when the convex portion and the waveguide layer are made of a resin, the wavelength selectivity of the reflected light to be emitted is improved by propagating the multiple reflected light into the waveguide layer. . In addition, since the nanoimprint method can be used as a method for forming the convex portion and the waveguide layer from the resin, it can be easily manufactured while reducing the material cost, and the manufacturing cost can be reduced.

  However, in the structure of Patent Document 2, the light propagation mode in the waveguide layer is mainly determined by the thickness of the waveguide layer and the wavelength of the light. In order to cause resonance, it is necessary to precisely control the thickness of the waveguide layer. Forming a waveguide layer with a precise film thickness in addition to the convex portion having a fine period has a large load on manufacturing, and therefore there is a limit to increasing the wavelength selectivity by the waveguide layer.

  An object of the present invention is to provide a display body capable of enhancing the function expressed by the appearance of the display body by utilizing the guided mode resonance phenomenon, and a method for manufacturing the display body.

  A display body that solves the above-described problem is a display body that includes a display element made of a material that transmits incident light, and that has a front surface and a back surface, and the display element includes a plurality of first sub-wavelength gratings. And a plurality of first low refractive index portions having a lower refractive index than the first high refractive index portion, and the first high refractive index portion in a direction along the surface. And a plurality of second high-refractive indexes that are formed of the same material as that of the first high-refractive-index portion and constitute a second sub-wavelength grating. And a plurality of second low refractive index portions having a refractive index lower than that of the second high refractive index portion, and the second high refractive index portion and the second low refractive index in a direction along the surface. Second grating regions in which the index portions are alternately positioned, an average refractive index of the first grating region, and an average refraction of the second grating region A first low-refractive index region, a second low-refractive index region, and a third low-refractive index region each having a lower refractive index than each of the first lattice region, and the first lattice region has a thickness of the display body. The second low-refractive index region and the second low-refractive index region are sandwiched between the first low-refractive index region and the second low-refractive index region in the vertical direction. The grating period of the first sub-wavelength grating and the grating period of the second sub-wavelength grating are sandwiched between the refractive index regions, and the plurality of first high refractions in the first grating region. The volume ratio of the refractive index portion and the volume ratio of the plurality of second high refractive index portions in the second lattice region are the same, and when viewed from the direction facing the surface, the first high refractive index portion and the volume ratio The second low refractive index portion overlaps, and the second high refractive index portion and the first low refractive index portion overlap. That.

  According to the above configuration, each grating region of the first grating region and the second grating region has a sub-wavelength grating, and each grating region has a lower refractive index than the refractive index of each grating region. Since it is sandwiched between the refractive index regions, when light enters each grating region, emission of diffracted light to the incident side space is suppressed in each grating region, and a waveguide mode resonance phenomenon occurs. Then, since the grating period of each grating region and the volume ratio of the high refractive index portion are the same, the wavelength range of light that causes resonance in the first grating region and the wavelength range of light that causes resonance in the second grating region Match.

  Therefore, the light in a specific wavelength region that leaks out in the process of multiple reflection in one grating region and enters the other grating region propagates while being reflected in the other grating region, and from the display element, the first The reflected light in the wavelength region strengthened in the grating region and the reflected light in the wavelength region strengthened in the second grating region are emitted. In the incident light, light in a wavelength range excluding the strengthened wavelength range passes through the display element and is emitted from the display element.

  As described above, according to the display element having the above-described configuration, the light in the wavelength region strengthened in each of the two grating regions is emitted as reflected light. Therefore, compared to the display element having only one grating region, The intensity of light in the specific wavelength range emitted as reflected light increases. Therefore, the vividness and brightness of the color visually recognized in the display area are enhanced, and as a result, the visibility of the image formed by the display body is enhanced. As a result, it is expressed by the difficulty and design of counterfeiting, that is, the appearance of the display body. Function is enhanced.

  In the above configuration, the display body includes a plurality of display elements, and the plurality of display elements include a first display element and a second display element, and when viewed from a direction facing the surface, The display body includes a first display area in which the first display element is located, and a second display area in which the second display element is located, and the first sub-wavelength grating and the second in the first display element The grating period of the sub-wavelength grating and the grating periods of the first sub-wavelength grating and the second sub-wavelength grating in the second display element may be different from each other.

  According to the said structure, the hue of the color visually recognized by the 1st display area and the 2nd display area can be varied. Therefore, various images can be expressed by these regions. In addition, since the difference in visible hue is realized by the difference in the grating period of the sub-wavelength grating, the difference in the manufacturing process of the display element due to the difference in color is small, and the display body can be manufactured easily.

  In the above-described configuration, a portion constituted by the first grating region, the second grating region, the first low refractive index region, the second low refractive index region, and the third low refractive index region is a resonance structure portion. The display element may include a plurality of the resonance structures arranged in the thickness direction of the display body.

  According to the above configuration, since the display element includes four or more lattice regions, the wavelength selectivity of the reflected light emitted from the display element is further improved, and the wavelength range included in the reflected light and transmitted light is adjusted. It is possible to increase the degree of freedom. Therefore, the visibility of the image formed by the display body can be increased, and the degree of freedom in adjusting the hue of the image visually recognized by the display body can be increased.

  In the above configuration, the plurality of resonance structures include a first resonance structure and a second resonance structure, and the first sub-wavelength grating and the second sub-wavelength grating included in the first resonance structure The first structural period that is the grating period of the first subwavelength grating may be different from the second structural period that is the grating period of the first subwavelength grating and the second subwavelength grating that the second resonance structure unit has.

  According to the above configuration, the wavelength range of light that causes resonance in each lattice region of the first resonance structure portion and the wavelength range of light that causes resonance in each lattice region of the second resonance structure portion are mutually different. Different. Therefore, when light is incident on the display element, light in a specific wavelength region is multiple-reflected in each lattice region of the upper resonance structure portion, and light in a wavelength region that is not multiple-reflected is transmitted through this resonance structure portion. Then, the light enters the lower resonance structure portion, and light in a wavelength region different from that of the upper resonance structure portion is multiple-reflected by each grating region of the lower resonance structure portion. As a result, from the display element, the light in the first wavelength region strengthened in the lattice region of the first resonance structure portion and the second wavelength region intensified in the lattice region of the second resonance structure portion. Reflected light including light is emitted. In addition, in the wavelength range included in the light incident on the display element, light in the wavelength range excluding the first wavelength range and the second wavelength range emitted as the reflected light is emitted as transmitted light. Therefore, in the display element, it is possible to increase the wavelength range included in the reflected light while increasing the intensity of the reflected light, and to narrow the wavelength range included in the transmitted light. Therefore, it is possible to increase the degree of freedom in adjusting the hue observed as reflected light or transmitted light through the setting of the grating period of the sub-wavelength grating included in each resonance structure, and the image that is visually recognized on the display body. The degree of freedom in adjusting the hue of the image can be increased.

  In the above configuration, the display body includes a plurality of display elements, and the plurality of display elements include a first display element and a second display element, and when viewed from a direction facing the surface, The display body includes a first display area in which the first display element is located and a second display area in which the second display element is located, and the first structure period and the second structure in the first display element. At least one of the first structure period and the second structure period may be different between the combination of the period and the combination of the first structure period and the second structure period in the second display element.

  According to the above configuration, the first display element and the second display element have different wavelength ranges of light emitted as reflected light, and different wavelength ranges of light emitted as transmitted light. Thereby, the first display area and the second display area appear to have different colors. According to such a configuration, since the difference in hue visually recognized in each region is realized by the difference in the combination of the first structural period and the second structural period in the display element, freedom of adjustment of the hue of the visually recognized image is achieved. The degree is increased.

  In the above-described configuration, in each of the plurality of resonance structures, the plurality of first high refractive index portions, the plurality of first low refractive index portions, the plurality of second high refractive index portions, and the plurality of second refractive index portions. 2 The element part which is each of the low refractive index parts has a shape extending in a band shape in one direction, and the plurality of resonance structure parts include a first resonance structure part and a second resonance structure part, The extending direction of the element part of the first resonance structure part and the extending direction of the element part of the second resonance structure part may be different from each other.

  According to the above configuration, in the grating region of each resonance structure portion, light polarized in the direction corresponding to the arrangement direction of the sub-wavelength gratings among the light included in the incident light causes resonance. Since the arrangement directions of the sub-wavelength gratings are different between the first resonance structure portion and the second resonance structure portion, the grating region of the first resonance structure portion and the grating region of the second resonance structure portion are included in the incident light. Among the emitted light, light polarized in different directions resonates and is emitted from the respective resonance structures. Therefore, since the reflected light is efficiently emitted with respect to the incident light including polarization components in various directions, the intensity of the reflected light is further increased. Therefore, in a display body that is observed under external light including polarization components in various directions, a high effect of improving the clearness and brightness of the color visually recognized in the display area can be obtained. Designability is further improved.

In the above configuration, the extending direction of the element portion of the first resonance structure portion and the extending direction of the element portion of the second resonance structure portion are directions along the surface and orthogonal to each other. May be.
According to the above configuration, reflected light is more efficiently emitted with respect to incident light including polarization components in various directions. In addition, the display element can be easily designed and manufactured.

In the above configuration, the first low refractive index region, the first low refractive index portion, and the portion adjacent to the first low refractive index portion in the second low refractive index region are continuous with each other. 1st structure which is one structure, adjacent to said 2nd low refractive index part in said 3rd low refractive index area | region, said 2nd low refractive index part, and said 2nd low refractive index area | region The portion to be may be a second structure which is one structure that is continuous with each other.
According to the above configuration, since a portion that is one structure can be manufactured in one process, the display can be easily manufactured.

  In the above configuration, a difference in refractive index between the first structure, the first high refractive index portion, and the second high refractive index portion is greater than 0.2, and the second structure and the first high refractive index. And the second high refractive index portion may have a refractive index difference greater than 0.2.

  According to the above configuration, the waveguide mode resonance phenomenon is preferably easily generated in each grating region, and the intensity of reflected light from each grating region is further increased. Therefore, the forgery difficulty and the design are further enhanced.

  In the above configuration, the material constituting the first structure is any one of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin, and the material constituting the second structure is an ultraviolet curable resin. The material that is one of a resin, a thermosetting resin, and a thermoplastic resin and that constitutes the first high refractive index portion and the second high refractive index portion may include an inorganic compound.

  According to the above configuration, the waveguide mode resonance phenomenon is preferably easily generated in each grating region, and the intensity of reflected light from each grating region is further increased. Therefore, the forgery difficulty and the design are further enhanced. Further, it is possible to reduce the material cost required for manufacturing the display body and to apply a simple manufacturing method such as a nanoimprint method.

  In the above configuration, the second low refractive index region has a third high refractive index portion made of the same material as the first high refractive index portion and the second high refractive index portion, and the third high refractive index portion The refractive index portion is in the thickness direction of the second low refractive index region between the end portions of the first high refractive index portion and the second high refractive index portion that are adjacent to each other when viewed from the direction facing the surface. It may extend along.

  According to the said structure, formation of the high refractive index part using a vacuum evaporation method is possible, and suitable formation of a subwavelength grating is possible. Even in this case, the configuration of the second low refractive index region for causing the guided mode resonance phenomenon is suitably realized.

  A manufacturing method of a display body that solves the above problem is a manufacturing method of a display body including a display element made of a material that transmits incident light, and the step of manufacturing the display element includes a first low refractive index material. A plurality of convex portions arranged in a sub-wavelength period, and concave portions alternately arranged with the convex portions along a direction in which the plurality of convex portions are arranged, viewed from a direction facing the surface. A first step of forming a concavo-convex structure layer having the convex portions and the concave portions by forming a plurality of concave portions having an area equal to an area of the plurality of convex portions; and from the first low refractive index material A second step of forming a high refractive index layer having a thickness smaller than the height of the convex portion on the surface of the concavo-convex structure layer using a high refractive index material having a high refractive index, As a refractive index layer, a first sub-wavelength case located on the recess. And a second step of forming a layer including a second sub-wavelength grating having the same grating period as that of the first sub-wavelength grating, located on the convex portion, and the concavo-convex structure layer and the high refractive index layer And forming a buried layer made of a second low refractive index material having a refractive index lower than that of the high refractive index material on the surface of the structure made of the second subwavelength grating. And a third step of filling with the second low refractive index material up to the top.

  By the said manufacturing method, the display body in which the function expressed by the said display body, ie, the external appearance of a display body, was improved can be manufactured. And according to the said manufacturing method, since the wavelength selectivity of the reflected light inject | emitted from a display element is improved, without controlling the precise film thickness of the layer which touches a subwavelength grating, the said function was improved. The display body can be easily manufactured.

  In the manufacturing method, in the first step, the intaglio is pressed against a coating layer made of a resin that is the first low-refractive index material, and after the resin is cured, the intaglio is released to form unevenness of the intaglio. The uneven structure layer is formed by transferring to the resin, and in the second step, the high refractive index layer is formed using a material containing an inorganic compound as the high refractive index material, and the third step. Then, the buried layer may be formed by applying a resin, which is the second low refractive index material, to the surface of the structure, and curing the applied resin.

  According to the said manufacturing method, since the uneven | corrugated structure layer is formed using the nanoimprint method, the uneven structure layer which has fine unevenness | corrugation can be formed suitably and simply.

  In the manufacturing method, in the third step, the two structures are opposed so that the high refractive index layers face each other, and a region between the two structures is filled with the second low refractive index material. The buried layer may be formed by:

  According to the said manufacturing method, the display element provided with four or more subwavelength gratings can be manufactured easily. Therefore, it is easy to manufacture a display body including such display elements.

  According to the present invention, the function expressed by the appearance of the display body can be enhanced by utilizing the waveguide mode resonance phenomenon.

The figure which shows the planar structure of a display body about 1st Embodiment of a display body. The figure which shows the cross-sectional structure of the pixel with which the display body of 1st Embodiment is provided, and the planar structure of a lattice area | region. The figure which shows the effect | action of the display body of 1st Embodiment. The figure which shows the formation process of an uneven structure layer about 1st Embodiment of the manufacturing method of a display body. The figure which shows the formation process of a high refractive index layer about 1st Embodiment of the manufacturing method of a display body. The figure which shows the formation process of a buried layer about 1st Embodiment of the manufacturing method of a display body. Sectional drawing which shows the structural example of the 2nd low refractive index area | region in the pixel with which the display body of 1st Embodiment is provided. Sectional drawing which shows the modification of the pixel with which the display body of 1st Embodiment is provided. Sectional drawing which shows the modification of the pixel with which the display body of 1st Embodiment is provided. Sectional drawing which shows an example of the cross-sectional structure of the pixel with which a display body is provided about 2nd Embodiment of a display body. Sectional drawing which shows an example of the cross-sectional structure of the pixel with which a display body is provided about 2nd Embodiment of a display body. The figure which shows the state with which the uneven structure body was faced about 2nd Embodiment of the manufacturing method of a display body. The figure which shows the formation process of a buried layer about 2nd Embodiment of the manufacturing method of a display body. The perspective view which shows the perspective structure of the pixel with which a display body is provided about 3rd Embodiment of a display body. The perspective view which divides and shows the pixel with which a display body is provided for every area | region about 3rd Embodiment of a display body. The top view which shows the planar structure of the lattice area | region in the display body of a modification. The perspective view which shows the perspective structure of the uneven structure layer in the display body of a modification. The figure which simplifies and shows the subwavelength grating pattern of an Example.

  (First embodiment)

  1st Embodiment of a display body and the manufacturing method of a display body is described with reference to FIGS. The display body may be used for the purpose of increasing the difficulty of counterfeiting the article, may be used for the purpose of improving the design of the article, or may be used for these purposes. For the purpose of increasing the difficulty of counterfeiting goods, for example, the display body is used for authentication documents such as passports and licenses, securities such as gift certificates and checks, cards such as credit cards and cash cards, and banknotes. It is pasted. In addition, for the purpose of improving the design of the article, the display body is, for example, a decorative article worn by the user, an article carried by the user, an article placed like a furniture or a household appliance, a wall or a door. It can be attached to structures.

Incident light applied to the display body of the present embodiment is light that is visible to the human naked eye, that is, light in the visible region. In the following, the wavelength of light in the visible region is set to be 400 nm or more and 800 nm or less.

[Configuration of the display body]
With reference to FIG. 1 and FIG. 2, the structure of the display body of 1st Embodiment is demonstrated.
As shown in FIG. 1, the display body 100 has a front surface 100F and a back surface 100R that is a surface opposite to the front surface 100F, and includes a first pixel 10A, a second pixel 10B, and a third pixel 10C. A plurality of pixels 10 are provided. The pixel 10 is an example of a display element.

  The display body 100 includes a first display area 110A, a second display area 110B, and a third display area 110C as viewed from the direction facing the surface 100F. The first display region 110A is a region where a plurality of first pixels 10A are arranged, the second display region 110B is a region where a plurality of second pixels 10B are arranged, and the third display region 110C is A region where a plurality of third pixels 10C are arranged. In other words, the first display area 110A is composed of a set of a plurality of first pixels 10A, and the second display area 110B is composed of a set of a plurality of second pixels 10B. 110C is composed of a set of a plurality of third pixels 10C.

  The first pixel 10A, the second pixel 10B, and the third pixel 10C have different hues, that is, the first display area 110A, the second display area 110B, and the third display area 110C have different hues. It is an area where the color of is visually recognized. Each of the first display area 110A, the second display area 110B, and the third display area 110C may be a character, a symbol, a figure, a pattern, a picture, or the like depending on these areas alone or a combination of two or more of these areas. Express the background of As an example, in the configuration shown in FIG. 1, a circular graphic is represented by the first display area 110A, a triangular graphic is represented by the second display area 110B, and a background is represented by the third display area 110C.

A detailed structure of the pixel 10 will be described with reference to FIG. The structure described below is common to the first pixel 10A, the second pixel 10B, and the third pixel 10C.
As shown in FIG. 2, the pixel 10 includes a base material 11, a first low refractive index region 12, a first lattice region 13, a second low refractive index region 14, a second lattice region 15, and a third low refractive index. Region 16 is provided. Each of the first low-refractive index region 12, the first lattice region 13, the second low-refractive index region 14, the second lattice region 15, and the third low-refractive index region 16 spreads in layers, and the substrate 11 They are arranged in this order from a position close to. The direction in which the regions are arranged is the first direction, and the first direction is the thickness direction of each region, and is the thickness direction of the display body 100, that is, the direction from the back surface 100R toward the front surface 100F. In addition, the third low refractive index region 16 side with respect to the base material 11 is the surface side of the display body 100, and the base material 11 side with respect to the third low refractive index region 16 is the back surface side of the display body 100. FIG. 2 shows a cross-sectional structure of the pixel 10 and also shows a planar structure of the first lattice region 13 and a planar structure of the second lattice region 15 with these regions partially broken.

  The base material 11 has a plate shape, and the surface located on the surface side of the display body 100 among the surfaces of the base material 11 is the surface of the base material 11. When the incident light on the display body 100 is light in the visible region, as the base material 11, for example, a synthetic quartz substrate, or a film made of a resin such as polyethylene terephthalate or polyethylene naphthalate is used.

  The first low refractive index region 12 is in contact with the surface of the base material 11 and extends along the surface of the base material 11. The first lattice region 13 includes a plurality of first high refractive index portions 13a and a plurality of first low refractive index portions 13b. Each of the first high refractive index portion 13a and the first low refractive index portion 13b is one direction as viewed from the direction facing the surface 100F of the display body 100, that is, as viewed from the direction along the first direction. It has the strip | belt shape extended along the 2nd direction which is. The first high refractive index portions 13a and the first low refractive index portions 13b are alternately arranged along a third direction orthogonal to the second direction. The second direction and the third direction are directions along the surface 100F of the display body 100, and each of the second direction and the third direction is orthogonal to the first direction. The first grating region 13 is sandwiched between the first low refractive index region 12 and the second low refractive index region 14 along the first direction, and is in contact with each of these regions.

  The second grating region 15 has a plurality of second high refractive index portions 15a and a plurality of second low refractive index portions 15b. Each of the second high refractive index portion 15a and the second low refractive index portion 15b has a band shape extending along the second direction when viewed from the direction along the first direction, and the second high refractive index portion 15a and the second low refractive index portions 15b are alternately arranged along the third direction. That is, the extending direction of the first high refractive index portion 13a and the first low refractive index portion 13b and the extending direction of the second high refractive index portion 15a and the second low refractive index portion 15b coincide with each other. The direction in which the refractive index portion 13a and the first low refractive index portion 13b are aligned with the direction in which the second high refractive index portion 15a and the second low refractive index portion 15b are aligned. Then, when viewed from the direction along the first direction, the first high refractive index portion 13a and the second low refractive index portion 15b overlap, and the second high refractive index portion 15a and the first low refractive index portion 13b overlap. ing. The second grating region 15 is sandwiched between the second low-refractive index region 14 and the third low-refractive index region 16 along the first direction, and is in contact with each of these regions. In FIG. 2, the planar structure of the first grating region 13 and the second grating region 15 is shown by adding dots to the first high refractive index portion 13a and the second high refractive index portion 15a.

  The first high refractive index portion 13a and the second high refractive index portion 15a are made of the same material, that is, the refractive index of the first high refractive index portion 13a and the refractive index of the second high refractive index portion 15a. Are equal to each other. The refractive indexes of the first high refractive index portion 13a and the second high refractive index portion 15a are higher than the refractive indexes of the first low refractive index portion 13b and the second low refractive index portion 15b. Furthermore, the refractive index of the first high refractive index portion 13a and the second high refractive index portion 15a is the same as that of each of the first low refractive index region 12, the second low refractive index region 14, and the third low refractive index region 16. It is higher than the refractive index.

  Each of the first low refractive index region 12, the second low refractive index region 14, the third low refractive index region 16, the first low refractive index portion 13b, and the second low refractive index portion 15b is made of the same material. I.e., their refractive indices are all equal. The refractive index of the first low refractive index region 12 is constant regardless of the portion in the region, the refractive index of the second low refractive index region 14 is also constant regardless of the portion in the region, and the third low refractive index region 12 is low. The refractive index of the refractive index region 16 is also constant regardless of the region within the region.

  The length of the first high refractive index portion 13a in the third direction is the first high element width Dh1, and the length of the first low refractive index portion 13b in the third direction is the first low element width Dl1. The total length of the first high element width Dh1 and the first low element width Dl1 is a period of arrangement of the first high refractive index portion 13a and the first low refractive index portion 13b in the first grating region 13. One cycle P1.

  The length of the second high refractive index portion 15a in the third direction is the second high element width Dh2, and the length of the second low refractive index portion 15b in the third direction is the second low element width Dl2. The total length of the second high element width Dh2 and the second low element width Dl2 is the period of the arrangement of the second high refractive index portion 15a and the second low refractive index portion 15b in the second grating region 15. Two periods P2.

  The first high element width Dh1, the first low element width Dl1, the second high element width Dh2, and the second low element width Dl2 are all equal. And the 1st period P1 and the 2nd period P2 are in agreement.

  The first period P1 and the second period P2 are smaller than the wavelength of light in the visible region, that is, each of the first period P1 and the second period P2 is a sub-wavelength period. In such a configuration, the plurality of first high refractive index portions 13a in the first grating region 13 and the plurality of second high refractive index portions 15a in the second grating region 15 cause the waveguide mode resonance phenomenon in the respective regions. A sub-wavelength grating is formed. The sub-wavelength grating formed by the first high refractive index portion 13a and the sub-wavelength grating formed by the second high refractive index portion 15a have the same grating period. That is, the pixel 10 has a structure in which two sub-wavelength gratings arranged with a gap in the first direction are embedded with a material having a refractive index lower than that of the material constituting these sub-wavelength gratings.

  The thickness of the first lattice region 13 is the first region thickness T1, and the thickness of the second lattice region 15 is the second region thickness T2. The first region thickness T1 and the second region thickness T2 are the same. The thickness of each of the first low refractive index region 12, the second low refractive index region 14, and the third low refractive index region 16 is not particularly limited.

  In the above configuration, the refractive index of the first grating region 13 is changed according to the volume ratio of the first high refractive index portion 13a and the first low refractive index portion 13b in the first grating region 13 to the first high refractive index portion 13a. And an average refractive index obtained by leveling the refractive index of the first low refractive index portion 13b. Since the volume ratio of the first high refractive index portion 13a and the first low refractive index portion 13b in the first grating region 13 is 1: 1, the average refractive index of the first grating region 13 is the first high refractive index portion. This is an average value of the refractive index of 13a and the refractive index of the first low refractive index portion 13b.

  Similarly, since the volume ratio of the second high refractive index portion 15a and the second low refractive index portion 15b is 1: 1, the average refractive index of the second grating region 15 is the refractive index of the second high refractive index portion 15a. This is the average value of the refractive index and the refractive index of the second low refractive index portion 15 b, and coincides with the average refractive index of the first grating region 13. The volume ratio of the first high refractive index portion 13 a in the first grating region 13 and the volume ratio of the second high refractive index portion 15 a in the second grating region 15 are equal.

  Here, in order to cause a guided mode resonance phenomenon in each of the first grating region 13 and the second grating region 15, the refractive index of the first grating region 13 and the first low refraction that sandwiches the first grating region 13 are used. The difference between the refractive index of each of the refractive index region 12 and the second low refractive index region 14 is preferably larger than 0.1. Similarly, the difference between the refractive index of the second grating region 15 and the refractive indexes of the second low refractive index region 14 and the third low refractive index region 16 sandwiching the second grating region 15 is 0.1. Is preferably larger.

  Therefore, the refractive index of the high refractive index material constituting the first high refractive index portion 13a and the second high refractive index portion 15a, the first low refractive index region 12, the second low refractive index region 14, and the third low refractive index. It is preferable that the difference between the refractive index of the low refractive index material constituting the region 16, the first low refractive index portion 13b, and the second low refractive index portion 15b is larger than 0.2.

When the incident light to the display body 100 is light in the visible region, examples of the low refractive index material include inorganic materials such as synthetic quartz, and polymer materials such as ultraviolet curable resins, thermoplastic resins, and thermosetting resins. In this case, as the high refractive index material, TiO ₂ (titanium oxide), Nb ₂ O ₅ (niobium oxide), Ta ₂ O ₅ (tantalum oxide), ZrO (zirconium oxide), ZnS An inorganic dielectric material such as (zinc sulfide) can be used.

  When all of the base material 11 and each of the regions 12 to 16 are made of a material that transmits light incident on the display body 100, the pixel 10 has wavelength selectivity for both reflected light and transmitted light. .

[Action of display body]
When light enters the pixel 10 from the surface side of the display body 100, the second grating region 15 has a sub-wavelength grating, and the second grating region 15 has a lower refractive index than the refractive index of the second grating region 15. Since the second low-refractive-index region 14 and the third low-refractive-index region 16 are sandwiched between the second grating region 15, the emission of diffracted light to the surface side is suppressed, and the guided mode resonance phenomenon occurs. Will occur. That is, light in a specific wavelength region propagates through the second grating region 15 while being multi-reflected to cause resonance, and the light in the specific wavelength region is emitted as reflected light on the surface side of the pixel 10. The wavelength range of light that causes resonance in the second grating region 15 is determined by the second high element width Dh2, the second period P2, and the second region thickness T2 in the second grating region 15.

Here, the light of the specific wavelength region propagating through the second grating region 15 is unlikely to be multiple-reflected by the second grating region 15 without loss, and a part of the light of the specific wavelength region is Each reflection in the two-grating region 15 leaks into the second low refractive index region 14. The leaked light passes through the second low refractive index region 14 and enters the first grating region 13.
Further, light in a wavelength range other than the specific wavelength range does not undergo multiple reflection at the second grating region 15, passes through the second low refractive index region 14, and enters the first grating region 13.

  When light enters the first grating region 13, the first grating region 13 has a sub-wavelength grating, and the first grating region 13 has a refractive index lower than the refractive index of the first grating region 13. Since it is sandwiched between the low refractive index region 12 and the second low refractive index region 14, the waveguide mode resonance phenomenon also occurs in the first grating region 13. The wavelength range of light that causes resonance in the first grating region 13 is determined by the first high element width Dh1, the first period P1, and the first region thickness T1 in the first grating region 13. In the first lattice region 13 and the second lattice region 15, the first high element width Dh1 coincides with the second high element width Dh2, the first period P1 coincides with the second period P2, and the first area thickness T1. Corresponds to the second region thickness T2. Therefore, the wavelength range of light that causes resonance in the first grating region 13 is the same as the wavelength range of light that causes resonance in the second grating region 15.

Therefore, the light that leaks in the process of multiple reflection at the second grating region 15 and enters the first grating region 13 propagates while being reflected at the first grating region 13 to cause resonance, and the surface of the display body 100 It is emitted as reflected light to the side.
Then, the light in the wavelength region that did not cause multiple reflection in the first grating region 13 passes through the first low refractive index region 12 and the base material 11 and exits to the back side of the display body 100.

  As a result, the light in the wavelength region enhanced by the second grating region 15 and the light in the wavelength region enhanced by the first grating region 13 are emitted from the pixel 10 to the surface side of the display body 100. Since the wavelength ranges of these lights are the same, the intensity of the light in the specific wavelength range emitted from the pixel 10 as reflected light is larger than that of a pixel having only one grating region, and the reflected light Wavelength selectivity is improved.

  In the wavelength range included in the incident light to the display body 100, light in a wavelength range other than the specific wavelength range emitted as the reflected light is transmitted from the pixel 10 to the back surface of the display body 100 as transmitted light. Injected to the side.

  When light is incident on the pixel 10 from the back side of the display body 100, the reflected light in the wavelength region strengthened by the second grating region 15 and the reflected light in the wavelength region strengthened by the first grating region 13 are used. Are emitted from the pixel 10 to the back side of the display body 100. Then, light in a wavelength range other than the wavelength range emitted as the reflected light in the wavelength range included in the incident light is emitted from the pixel 10 to the surface side of the display body 100 as transmitted light.

  Here, in the first pixel 10A, the second pixel 10B, and the third pixel 10C, the first period P1 of the first lattice region 13, that is, the second period P2 of the second lattice region 15 is different for each pixel. It is a different cycle. Therefore, in the first pixel 10 </ b> A, the second pixel 10 </ b> B, and the third pixel 10 </ b> C, the wavelength regions where resonance due to the waveguide mode resonance phenomenon occurs in the first grating region 13 and the second grating region 15 are different from each other.

  As a result, when receiving incident light including light of a plurality of wavelengths, the wavelength range of the reflected light emitted from the first pixel 10A, the wavelength range of the reflected light emitted from the second pixel 10B, and the third pixel The wavelength ranges of light emitted from 10C are different from each other. When receiving the incident light, the wavelength range of the transmitted light emitted from the first pixel 10A, the wavelength range of the transmitted light emitted from the second pixel 10B, and the transmitted light emitted from the third pixel 10C. Are different from each other.

  That is, as shown in FIG. 3, when the incident light I <b> 1 is irradiated from the outside of the display body 100 toward the surface 100 </ b> F of the display body 100, the reflected light from the first pixel 10 </ b> A is reflected on the surface side of the display body 100. I2 is emitted, reflected light I3 is emitted from the second pixel 10B, and reflected light I4 is emitted from the third pixel 10C. Accordingly, when the surface 100F of the display body 100 is viewed from the surface side, the hue of the hue corresponding to the wavelength range of the reflected light I2 is visually recognized in the first display area 110A, and the wavelength of the reflected light I3 is displayed in the second display area 110B. The hue color corresponding to the area is visually recognized, and the hue color corresponding to the wavelength area of the reflected light I4 is visually recognized in the third display area 110C. Since the wavelength range of the reflected light I2, the wavelength range of the reflected light I3, and the wavelength range of the reflected light I4 are different from each other, the first display area 110A, the second display area 110B, and the third display area 110C have different hues. Looks like the color.

  Therefore, according to the surface reflection observation in which the surface 100F is observed from the surface side of the display body 100 in a state where the incident light I1 is irradiated from the outside of the display body 100 toward the surface 100F, the first display of different colors is performed. An image composed of the area 110A, the second display area 110B, and the third display area 110C is visually recognized.

  Further, when the incident light I1 is irradiated from the outside of the display body 100 toward the front surface 100F of the display body 100, the transmitted light I5 is emitted from the first pixel 10A to the back side of the display body 100, and the second Transmitted light I6 is emitted from the pixel 10B, and transmitted light I7 is emitted from the third pixel 10C. Therefore, when the back surface 100R of the display body 100 is viewed from the back surface side, the color of the hue corresponding to the wavelength region of the transmitted light I5 is visually recognized in the first display region 110A, and the wavelength of the transmitted light I6 is displayed in the second display region 110B. The hue color corresponding to the region is visually recognized, and the hue color corresponding to the wavelength region of the transmitted light I7 is visually recognized in the third display region 110C. Since the wavelength range of the transmitted light I5, the wavelength range of the transmitted light I6, and the wavelength range of the transmitted light I7 are different from each other, the first display area 110A, the second display area 110B, and the third display area 110C have different hues. Looks like the color.

  Therefore, the first display areas having different colors are also obtained by backside transmission observation in which the back surface 100R is observed from the back surface side of the display body 100 in a state where the incident light I1 is irradiated from the outside of the display body 100 toward the front surface 100F. An image composed of 110A, the second display area 110B, and the third display area 110C is visually recognized.

  Further, since the wavelength range of the reflected light I2 and the wavelength range of the transmitted light I5 are different, the first display region 110A is seen when the display body 100 is viewed from the front surface side and when the display body 100 is viewed from the back surface side. The hue of the color that is visually recognized is different. The color visible from the back side is a color corresponding to the complementary color of the color seen from the front side. Similarly, when the display body 100 is viewed from the front surface side and when the display body 100 is viewed from the back surface side, the hue of the color visually recognized in the second display area 110B is different, and the color is visible in the third display area 110C. The hues of the colors that are produced are also different.

  As described above, according to the display body 100 of the first embodiment, the wavelength selectivity of the reflected light emitted from each of the pixels 10A, 10B, and 10C is enhanced, so that it is visually recognized in each of the display regions 110A, 110B, and 110C. The vividness and brightness of the selected colors are increased. Therefore, the visibility of the image formed by the display body 100 is enhanced, and as a result, the forgery of the article including the display body 100 and the design are increased.

  Also, images of different colors are visually recognized on the display body 100 in the front surface reflection observation and the rear surface transmission observation. Therefore, in the article provided with the display body 100, forgery difficulty and design are further improved. Further, the front and back of the display body 100 can be easily identified. Furthermore, in the display body 100 according to the first embodiment, since the flexible base material 11 such as a resin film can be used, it is possible to realize the display body 100 having a high degree of freedom in deformation of the shape. It is.

[Manufacturing method of display body]
With reference to FIGS. 4-6, the manufacturing method of the display body 100 mentioned above is demonstrated.
As shown in FIG. 4, when forming the pixel 10, first, a layer made of a low refractive index material is formed on the surface of the base material 11, and a concavo-convex structure layer is formed on the surface of this layer. 20 is formed. The concavo-convex structure layer 20 has a flat portion 20a extending along the base material 11 and a plurality of convex portions 20b protruding from the flat portion 20a, and also has a plurality of concave portions 20c which are portions located between the convex portions 20b. . The plurality of convex portions 20b are arranged at equal intervals in the sub-wavelength period and extend in a strip shape in one direction. The plurality of concave portions 20c are arranged in the same pattern as the plurality of convex portions 20b, and the area of the plurality of convex portions 20b is equal to the area of the plurality of concave portions 20c when viewed from the direction facing the surface of the substrate 11. .

  Depending on the wavelength range of light of the hue desired to be visually recognized by the pixel 10, the convex portion 20b and the concave portion 20c have the arrangement period Pt of the desired first period P1 and second period P2, and the width Dt1 of the convex part 20b. Are the desired first low element width Dl1 and the second high element width Dh2, and the width Dt2 of the recess 20c is the desired first high element width Dh1 and the second low element width Dl2. That is, the width Dt1 of the convex portion 20b is equal to the width Dt2 of the concave portion 20c. The height Ht of the convex portion 20b is formed to be larger than the desired first region thickness T1.

  For forming the concavo-convex structure, a known fine processing technique such as a nanoimprint method or a dry etching method is used. Among these, the nanoimprint method is preferable because the fine convex portions 20b and the concave portions 20c can be easily formed.

  For example, when the concavo-convex structure layer 20 is formed by an optical nanoimprint method using an ultraviolet curable resin as a low refractive index material, first, an ultraviolet curable resin is applied to the surface of the substrate 11. Next, a synthetic quartz mold, which is an intaglio plate having irregularities that are inverted from the projections 20b and recesses 20c to be formed, is pressed against the surface of the coating layer made of an ultraviolet curable resin, and applied to the coating layer and the intaglio plate. Irradiate ultraviolet rays. Subsequently, the intaglio is released from the cured ultraviolet curable resin. Thereby, the unevenness of the intaglio is transferred to the ultraviolet curable resin to form the convex portions 20b and the concave portions 20c, and the convex portions 20b and the concave portions 20c and the base material 11 are made of an ultraviolet curable resin. A flat portion 20a is formed as the remaining film.

  Next, as shown in FIG. 5, a high refractive index layer 21 made of a high refractive index material is formed on the surface of the concavo-convex structure layer 20. As a method for forming the high refractive index layer 21, a known film forming technique such as a vacuum deposition method is used. The high refractive index layer 21 is formed on the convex portion 20b and the concave portion 20c. That is, the high refractive index layer 21 includes a first layered portion 21a located on the concave portion 20c and a second layered portion 21b located on the convex portion 20b.

  Since the width Dt1 of the convex portion 20b and the width Dt2 of the concave portion 20c in the concavo-convex structure layer 20 are equal, the width Ds1 of the first layered portion 21a and the width Ds2 of the second layered portion 21b are equal. Further, the period of the arrangement of the first layered portions 21a and the period of the arrangement of the second layered portions 21b are the periods Pt, which are equal to each other. That is, the thickness of the high refractive index layer 21 is the thickness Ts1 of the first layered portion 21a and the thickness Ts2 of the second layered portion 21 and these thicknesses are equal. The thickness of the high refractive index layer 21 is smaller than the height Ht of the convex portion 20b, and is formed to have a desired first region thickness T1 and second region thickness T2. That is, the first layered portion 21a and the second layered portion 21b constitute a sub-wavelength grating having the same pattern.

  Next, as shown in FIG. 6, it is a layer made of the same low refractive index material as the material for forming the concavo-convex structure layer 20 so as to cover the surface of the structure made of the concavo-convex structure layer 20 and the high refractive index layer 21. A buried layer 22 is formed to fill the unevenness of the structure up to the second layered portion 21b. The buried layer 22 includes a flat portion 22a, a plurality of convex portions 22b, and a concave portion 22c located between the convex portions 22b. The convex portion 22b fills the space between the convex portions 20b and the second layered portion 21b on the first layered portion 21a. The flat portion 22 a is located on the second layered portion 21 b and extends in a direction along the surface of the base material 11. The flat part 22a and the convex part 22b are connected so that the convex part 22b protrudes toward the base material 11 from the flat part 22a.

  The period of the convex part 22b coincides with the period Pt of the convex part 20b in the concavo-convex structure layer 20, the width of the convex part 22b coincides with the width Dt2 of the concave part 20c, and the width of the concave part 22c is the width Dt1 of the convex part 20b. Matches. The height of the convex portion 20 b is larger than the thickness of the high refractive index layer 21.

  As a method for forming the buried layer 22, known film forming techniques such as various coating methods are used. For example, when an ultraviolet curable resin is used as the low refractive index material, first, the ultraviolet curable resin is applied to the surface of the structure. Next, a release plate is pressed against the surface of the coating layer made of an ultraviolet curable resin, and the coating layer is irradiated with ultraviolet rays. Subsequently, the flat plate is released from the cured ultraviolet curable resin. Therefore, when an ultraviolet curable resin is used, the planographic plate needs to be made of a material that transmits ultraviolet rays.

  Thereby, the pixel 10 is formed. The flat portion 20 a of the concavo-convex structure layer 20 is the first low refractive index region 12. A first lattice region 13 is configured from the first layered portion 21a of the high refractive index layer 21 and the portion adjacent to the first layered portion 21a in the protruding portion 20b of the concavo-convex structure layer 20, and the first layered portion 21a It is the 1st high refractive index part 13a, and the part adjacent to the 1st layered part 21a in the convex part 20b is the 1st low refractive index part 13b. Second from the portion extending from the first layered portion 21a in the convex portion 20b of the concavo-convex structure layer 20 and the portion adjacent to the convex portion 20b of the concavo-convex structure layer 20 in the convex portion 22b of the embedded layer 22. A low refractive index region 14 is formed.

  A second lattice region 15 is configured by the second layered portion 21b of the high refractive index layer 21 and a portion adjacent to the second layered portion 21b in the convex portion 22b of the buried layer 22, and the second layered portion 21b is 2 is the high refractive index portion 15a, and the portion adjacent to the second layered portion 21b in the convex portion 22b is the second low refractive index portion 15b. The flat portion 22 a of the buried layer 22 is the third low refractive index region 16.

  In the pixel 10 manufactured by such a manufacturing method, the first low refractive index region 12 and the first low refractive index portion 13b of the first grating region 13 are continuous, the first low refractive index portion 13b, A portion adjacent to the first low refractive index portion 13 b in the low refractive index region 14 is continuous, and the first low refractive index region 12, the first low refractive index portion 13 b, and the second low refractive index region 14. Among these, the portion adjacent to the first low refractive index portion 13b is one structure. In the second low refractive index region 14, the portion adjacent to the second low refractive index portion 15b of the second grating region 15 and the second low refractive index portion 15b are continuous, and the second low refractive index portion 15b. And the third low refractive index region 16 are continuous, a portion adjacent to the second low refractive index portion 15b in the second low refractive index region 14, a second low refractive index portion 15b, and a third low refractive index portion. The region 16 is a single structure.

  As described above, in the pixel 10, the light in the wavelength region enhanced by the first grating region 13 and the light in the wavelength region enhanced by the second grating region 15 are emitted, whereby the intensity of the reflected light is increased. growing. Therefore, for example, when the pixel 10 is formed using the nanoimprint method without requiring precise control of the film thickness of the layer in contact with the first lattice region 13 or the second lattice region 15, the film thickness of the remaining film. Therefore, it is possible to manufacture the pixel 10 that emits reflected light with high wavelength selectivity. Therefore, the display body 100 can be easily manufactured.

  Moreover, since the display body 100 can be formed by a manufacturing method in which an optical nanoimprint method and a vacuum deposition method are combined, it is suitable for manufacturing by a roll-to-roll method. Therefore, the structure of the display body 100 is also suitable for mass production.

  Here, between the first pixel 10A, the second pixel 10B, and the third pixel 10C, the base material 11, the first low refractive index region 12, the first lattice region 13, the second low refractive index region 14, the second Each of the grating region 15 and the third low refractive index region 16 is continuous. That is, the first pixel 10A, the second pixel 10B, and the third pixel 10C include a common base material 11, a concavo-convex structure layer 20 that is continuous between the pixels, and a mutual relationship between the pixels. And a continuous buried layer 22.

  The concavo-convex structure layer 20 in each of the first pixel 10A, the second pixel 10B, and the third pixel 10C changes the period of the concavo-convex at portions corresponding to the pixels 10A, 10B, and 10C using, for example, a nanoimprint method. By using a synthetic quartz mold, it can be formed simultaneously. Further, the high refractive index layer 21 and the buried layer 22 can also be formed simultaneously with portions corresponding to the pixels 10A, 10B, and 10C. Accordingly, it is possible to easily form the pixels 10A, 10B, and 10C that exhibit different colors.

  In addition, when forming the high refractive index layer 21 using a vacuum evaporation method, a high refractive index material may adhere also to the side surface of the convex part 20b of the uneven structure layer 20. FIG. As a result, as shown in FIG. 7, the second low refractive index region 14 is the end of the first high refractive index portion 13a and the second high refractive index portion 15a that are adjacent to each other when viewed from the direction along the first direction. A third high refractive index portion 17 extending in the thickness direction of the second low refractive index region 14 is included so as to connect the portions. The third high refractive index portion 17 may not completely connect the first high refractive index portion 13a and the second high refractive index portion 15a, and the third high refractive index portion 17 and the first high refractive index portion 17a may not be connected to each other. The index part 13a and the second high refractive index part 15a may be separated.

  Even when the third high refractive index portion 17 exists, the volume ratio of the third high refractive index portion 17 in the second low refractive index region 14 is very small. The portion constituted by the low refractive index material is dominant. Therefore, the refractive index of the second low refractive index region 14 is slightly larger than the refractive indexes of the first low refractive index region 12 and the third low refractive index region 16, but the first lattice region 13 and the second low refractive index region 14 It is sufficiently smaller than the refractive index of each of the grating regions 15. Accordingly, a structure suitable for the waveguide mode resonance phenomenon is realized in which each of the first grating region 13 and the second grating region 15 is sandwiched between regions having a refractive index lower than those regions.

[Modifications of display body]
In the above manufacturing method, the concavo-convex structure layer 20 may be formed by a nanoimprint method using a thermosetting resin or a thermoplastic resin instead of the ultraviolet curable resin. In the case of using a thermosetting resin, the irradiation of ultraviolet rays may be changed to heating, and in the case of using a thermoplastic resin, the irradiation of ultraviolet rays may be changed to heating and cooling.

  However, when the concavo-convex structure layer 20 is formed using a thermoplastic resin, a material different from the thermoplastic resin is used in order to prevent the concavo-convex structure layer 20 from being heated and deformed when the buried layer 22 is formed. It is preferable to form the buried layer 22.

  For example, as shown in FIG. 8, the concavo-convex structure layer 20 may be formed from a thermoplastic resin, and the buried layer 22 may be formed from an ultraviolet curable resin. In this case, the refractive index of the low refractive index material constituting the concavo-convex structure layer 20 and the refractive index of the low refractive index material constituting the buried layer 22 may be different from each other. The refractive index should be lower than the refractive index of the high refractive index material constituting the high refractive index layer 21.

  When the refractive index of the low refractive index material constituting the concavo-convex structure layer 20 and the refractive index of the low refractive index material constituting the buried layer 22 are different from each other, the first low refractive index region 12 is produced in the manufactured pixel 10. The refractive indices of the second low refractive index region 14 and the third low refractive index region 16 are different from each other. The second low-refractive index region 14 has a structure in which band-shaped portions made of materials having different refractive indexes extend along the second direction and are alternately arranged along the third direction.

  The concavo-convex structure layer 20 is formed from a thermoplastic resin, and the buried layer 22 is not limited to being formed from a material different from the thermoplastic resin. The refractive index of the low refractive index material constituting the layer 22 may be different from each other. In short, it is sufficient that the refractive index of the low refractive index material constituting each of the concavo-convex structure layer 20 and the buried layer 22 is lower than the refractive index of the high refractive index material constituting the high refractive index layer 21. In the manufactured pixel 10, the first low-refractive index region 12, the second low-refractive index region 14, and the third low-refractive index region 14 are lower than the refractive indexes of the first lattice region 13 and the second lattice region 15. Each of the refractive indexes of the refractive index region 16 may be low.

  Moreover, as FIG. 9 shows, the base material 11 and the uneven | corrugated structure layer 20 may be one structure which continued mutually. That is, the uneven structure layer 20 is formed by forming an uneven structure on the surface of the substrate 11 made of a low refractive index material. For example, an uneven structure may be formed on the surface of the base material 11 using a sheet made of a thermoplastic resin as the base material 11, or a surface of the base material 11 using a substrate made of synthetic quartz as the base material 11. An uneven structure may be formed on the surface. A well-known technique such as a dry etching method may be used to form the concavo-convex structure on the synthetic quartz substrate. In this case, in the manufactured pixel 10, the base material 11 and the first low refractive index region 12 are continuous with each other.

As described above, according to the first embodiment, the effects listed below can be obtained.
(1) In the pixel 10, when light enters each of the grating regions 13 and 15, a waveguide mode resonance phenomenon occurs in each of the grating regions 13 and 15. The wavelength range of light that causes resonance in the first grating region 13 matches the wavelength range of light that causes resonance in the second grating region 15. Accordingly, since light in the wavelength region intensified in each of the two grating regions 13 and 15 is obtained as reflected light, light emitted as reflected light from the pixel 10 as compared with a configuration having only one grating region. The strength of is increased. That is, the wavelength selectivity of light emitted from the pixel 10 is improved. Therefore, since the vividness and brightness of the color visually recognized in the display area 110 are enhanced, the visibility of the image formed by the display body 100 is enhanced. As a result, the forgery difficulty and design properties, that is, the appearance of the display body 100 are improved. The function expressed by is enhanced.

  Also, images of different colors are visually recognized on the display body 100 in the front surface reflection observation and the rear surface transmission observation. Therefore, in the article provided with the display body 100, forgery difficulty and design are further improved. Further, the front and back of the display body 100 can be easily identified.

  (2) Since the display body 100 includes the pixels 10A, 10B, and 10C having different grating periods of the sub-wavelength gratings, the pixels 10A, 10B, and 10C are positioned in each of the front surface reflection observation and the rear surface transmission observation. In the display areas 110A, 110B, and 110C to be displayed, colors having different hues are visually recognized. Therefore, various images can be expressed by these areas. In addition, since the difference in the visible hue is realized by the difference in the grating period of the sub-wavelength grating, the difference in the pixel manufacturing process due to the difference in color is small, and the display body 100 can be easily manufactured.

  (3) A step of forming the concavo-convex structure layer 20 made of a low refractive index material, a step of forming the high refractive index layer 21 on the surface of the concavo-convex structure layer 20, and the concavo-convex structure layer 20 and the high refractive index layer 21. The pixel 10 is formed by the step of forming the buried layer 22 made of a low refractive index material on the surface of the structure. Therefore, since the wavelength selectivity of the reflected light emitted from the pixel 10 is increased without requiring precise control of the thickness of the layer in contact with the sub-wavelength grating, display with improved counterfeiting difficulty and designability The body 100 can be easily manufactured.

  (4) In particular, in a manufacturing method in which a resin is used as a low refractive index material and an intaglio is pressed against a coating layer made of resin and the uneven structure layer 20 is formed by curing the resin, the formation of the uneven structure layer 20 using a nanoimprint method. Therefore, the uneven structure layer 20 having fine unevenness can be suitably and easily formed.

  (5) The first low refractive index region 12, the first low refractive index portion 13b, and the portion adjacent to the first low refractive index portion 13b in the second low refractive index region 14 are mutually continuous 1 A third low refractive index region 16, a second low refractive index portion 15b, and a portion of the second low refractive index region 14 adjacent to the second low refractive index portion 15b. In the structure which is one continuous structure, each of the parts which are one structure can be manufactured in one process using the above-described manufacturing method, so that the display body 100 can be easily manufactured. It is.

  (6) In the configuration in which the refractive index difference between each of the structures and the first high refractive index portion 13a and the second high refractive index portion 15a is larger than 0.2, the waveguide mode is used in each of the grating regions 13 and 15. A resonance phenomenon is preferably easily generated, and the intensity of reflected light from each of the grating regions 13 and 15 is further increased. Therefore, the forgery difficulty and the design are further enhanced.

  (7) The low refractive index material constituting each of the structures is any one of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin, and the first high refractive index portion 13a and the second high refractive index. When the material constituting the portion 15a includes an inorganic compound, the waveguide mode resonance phenomenon is preferably easily generated in each of the lattice regions 13 and 15, and the intensity of reflected light from each of the lattice regions 13 and 15 is further increased. It is done. Therefore, the forgery difficulty and the design are further enhanced. Further, it is possible to reduce the material cost required for manufacturing the display body 100 and to apply a simple manufacturing method such as a nanoimprint method.

  (8) The second low refractive index region 14 has a second low refractive index between the ends of the first high refractive index portion 13a and the second high refractive index portion 15a that are adjacent to each other when viewed from the direction along the first direction. In the configuration including the third high refractive index portion 17 extending along the thickness direction of the refractive index region 14, it is possible to form the high refractive index portions 13a and 15a using a vacuum deposition method, which is suitable for the sub-wavelength grating. Formation is possible. Even in this case, the configuration of the second low refractive index region 14 for causing the waveguide mode resonance phenomenon is suitably realized.

(Second Embodiment)
With reference to FIGS. 10-13, 2nd Embodiment of the display body and the manufacturing method of a display body is described. The second embodiment differs from the first embodiment in the pixel structure. Below, it demonstrates centering around the difference between 2nd Embodiment and 1st Embodiment, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

[Pixel configuration]
With reference to FIG. 10 and FIG. 11, the structure of the pixel with which the display body of 2nd Embodiment is provided is demonstrated. As illustrated in FIG. 10, the pixel 10 includes the first low refractive index region 12, the first lattice region 13, the second low refractive index region 14, the second lattice region 15, and the first embodiment described in the first embodiment. 3 Two resonance structures 18, which are structures composed of the low refractive index regions 16, are provided.

  The first resonance structure portion 18A and the second resonance structure portion 18B, which are the two resonance structure portions 18, are adjacent to each other in the first direction, and the two resonance structure portions 18A and 18B are sandwiched between the two base materials 11. It is. In other words, the pixel 10 of the second embodiment has a structure in which two pixels having the configuration of the first embodiment are joined so that the third low refractive index regions 16 face each other. That is, the pixel 10 of the second embodiment has four sub-wavelength gratings arranged in the first direction with a space therebetween, and has a structure in which these sub-wavelength gratings are embedded in a low refractive index material. In addition, the side of the other base material 11 with respect to the one base material 11 is the surface side of the display body 100, and the side of the one base material 11 with respect to the other base material 11 is the back surface side of the display body 100.

  In the two resonance structure portions 18A and 18B, the extending directions of the high refractive index portions 13a and 15a coincide with each other. That is, all the first high refractive index portions 13a and the second high refractive index portions 15a included in the pixel 10 extend along the second direction, and all the first low refractive index portions 13b and the second low refractive index portions 13b included in the pixel 10 are included. The refractive index portion 15b also extends along the second direction. In each of the four lattice regions 13 and 15 of the pixel 10, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b are alternately arranged along the third direction. That is, the arrangement directions of the sub-wavelength gratings are the same for the four sub-wavelength gratings included in the pixel 10.

  Note that, when viewed from the direction along the first direction, the first high refractive index portion 13a of the first resonant structure portion 18A may overlap the first high refractive index portion 13a of the second resonant structure portion 18B, It may overlap with the second high refractive index portion 15a of the second resonant structure portion 18B, or may be part of the first high refractive index portion 13a and part of the second high refractive index portion 15a of the second resonant structure portion 18B. It may overlap.

  The first resonance structure 18A and the second resonance structure 18B may share a low refractive index region at the boundary between these. For example, in the example illustrated in FIG. 10, the third low refractive index region 16 included in the first resonance structure 18A and the third low refractive index region 16 included in the second resonance structure 18B are continuous. There are no region boundaries.

  In one resonance structure 18, the first period P 1 of the first grating region 13 and the second period P 2 of the second grating region 15 are the same, and this period is the structure period Pk of the resonance structure 18. .

  The structural period Pk of the first resonant structure 18A and the structural period Pk of the second resonant structure 18B may be the same as shown in FIG. 10, or may be different from each other as shown in FIG. Good.

  In the form in which the two resonance structures 18A and 18B have the same structure period Pk, the patterns of the four sub-wavelength gratings included in the pixel 10 are all the same, and the high element widths Dh1 and Dh2 in the resonance structures 18A and 18B. Are all equal and the region thicknesses T1, T2 are all equal. In the form in which the two resonance structures 18A and 18B have different structural periods Pk, the patterns of the four sub-wavelength gratings included in the pixel 10 are different for each resonance structure 18A and 18B. That is, the high element widths Dh1 and Dh2 are different for each of the resonance structures 18A and 18B. The region thicknesses T1 and T2 may all be equal, or may be different for each of the resonance structures 18A and 18B.

[Action of display body]
In the configuration in which the two resonance structures 18A and 18B have the same structural period Pk, the wavelength range of light causing resonance is the same in all of the four grating regions 13 and 15 of the pixel 10. Therefore, when light is incident on the pixel 10 from the surface side of the display body 100, light leaking from the grating region in the process of multiple reflection out of light in a specific wavelength region that is multiply reflected by the upper grating region is Then, it enters the underlying lattice region and undergoes multiple reflections, and this phenomenon is repeated for the number of lattice regions. As a result, the reflected light of a specific wavelength region strengthened by each of the four grating regions 13 and 15 is emitted to the surface side of the display body 100. Therefore, compared with the display body of 1st Embodiment, the intensity | strength of the light of the said specific wavelength range inject | emitted as reflected light from the display body 100 becomes larger, and the wavelength selectivity of reflected light is improved more. As a result, in the display body 100, the visibility of the image is enhanced by increasing the vividness and brightness of the colors visually recognized in the display areas 110A, 110B, and 110C in the surface reflection observation.

  On the other hand, in the configuration in which the two resonance structures 18A and 18B have different structural periods Pk, the wavelength range of light that causes resonance in the lattice regions 13 and 15 of the first resonance structure 18A, and the second resonance structure The wavelength range of light that causes resonance in the grating regions 13 and 15 of 18B is different from each other. Therefore, when light is incident on the pixel 10 from the surface side of the display body 100, the wavelength region in which light in a specific wavelength region is multiple-reflected and not multiple-reflected in each of the lattice regions 13 and 15 of the upper resonance structure portion 18. Is transmitted through the resonance structure 18 and enters the lower resonance structure 18, and light in a wavelength region different from that of the upper resonance structure 18 is transmitted to each grating region 13, 15 for multiple reflections. As a result, on the surface side of the display body 100, the light in the first wavelength band strengthened by the grating regions 13 and 15 included in the first resonance structure 18A and the grating region 13 included in the second resonance structure 18B. , 15, the reflected light including the light in the second wavelength band enhanced by 15 is emitted from the pixel 10.

  And on the back surface side of the display body 100, in the wavelength range included in the incident light to the display body 100, in the wavelength range excluding the first wavelength range and the second wavelength range emitted as the reflected light. Light is emitted from the pixel 10 as transmitted light. According to such a configuration, in the pixel 10, it is possible to expand the wavelength range included in the reflected light while increasing the intensity of the reflected light, and to narrow the wavelength range included in the transmitted light. Therefore, the degree of freedom in adjusting the hue observed as reflected light or transmitted light can be increased through the setting of the structural period Pk in the resonance structure portions 18A and 18B.

  The first pixel 10A, the second pixel 10B, and the third pixel 10C have different combinations of the structural period Pk of the first resonant structure 18A and the structural period Pk of the second resonant structure 18B. . That is, a combination of the structural period Pk of the first resonant structure 18A in the first pixel 10A and the structural period Pk of the second resonant structure 18B, and the structural period Pk of the first resonant structure 18A in the second pixel 10B The combination with the structural period Pk of the second resonant structure 18B differs in at least one of the structural period Pk of the first resonant structure 18A and the structural period Pk of the second resonant structure 18B. The same applies to the combination of the structural period Pk in the second pixel 10B and the third pixel 10C and the combination of the structural period Pk in the first pixel 10A and the third pixel 10C.

  With such a configuration, the first pixel 10A, the second pixel 10B, and the third pixel 10C have different wavelength ranges of light emitted as reflected light, and different wavelength ranges of light emitted as transmitted light. ing. Thereby, in each of the front surface reflection observation and the back surface transmission observation, the first display region 110A, the second display region 110B, and the third display region 110C appear to have different hue colors. According to such a configuration, the degree of freedom in adjusting the hue of the image visually recognized in the front surface reflection observation and the rear surface transmission observation is increased.

[Manufacturing method of display body]
With reference to FIG. 12 and FIG. 13, the manufacturing method of the display body 100 of 2nd Embodiment is demonstrated. First, in manufacturing the pixel 10 according to the second embodiment, the concavo-convex structure layer 20 and the high refractive index layer 21 are sequentially formed on the substrate 11 as in the first embodiment.

  Subsequently, as shown in FIG. 12, the two concavo-convex structure bodies 31, which are structures including the base material 11, the concavo-convex structure layer 20, and the high refractive index layer 21, face each other so that the high refractive index layers 21 face each other. Then, as shown in FIG. 13, these concavo-convex structures 31 are joined by filling a region between the two concavo-convex structures 31 with a low refractive index material. Thereby, the pixel 10 is formed.

  As shown in FIG. 13, the portion formed between the two concavo-convex structures 31 by embedding with the low refractive index material is the buried layer 22. As in the first embodiment, if the low refractive index material constituting the buried layer 22 is a material having a lower refractive index than the high refractive index material constituting the high refractive index layer 21, the concavo-convex structure layer 20 is constituted. A material different from the material may be used. In the two concavo-convex structures 31, the low refractive index material constituting the concavo-convex structure layer 20 and the high refractive index material constituting the high refractive index layer 21 may be different from each other.

  In the state where the two concavo-convex structures 31 are opposed to each other, the first layer portions 21 a may face each other, or the first layer portion 21 a in one concavo-convex structure body 31 and the first layer portion 21 a in the other concavo-convex structure body 31. The two-layered portion 21b may face each other. Alternatively, the first layered portion 21a in one concavo-convex structure 31 may face part of the first layered portion 21a and part of the second layered portion 21b in the other concavo-convex structure 31.

  For example, as the two concavo-convex structures 31, the concavo-convex structure 31 having the same period Pt of the protrusions 20 b is joined to form the pixel 10 in which the two resonance structures 18 </ b> A and 18 </ b> B have the same structure period Pk. it can. Further, for example, as the two concavo-convex structure bodies 31, by joining the concavo-convex structure bodies 31 having the protrusions 20b having different periods Pt, the pixels 10 having the two resonance structure parts 18A and 18B having the different structure periods Pk are formed. it can.

  Note that the pixel 10 may include three or more resonance structures 18 arranged in the first direction. In the configuration in which the pixel 10 includes a plurality of resonance structure portions 18, if the structure period Pk in the resonance structure portions 18 is the same, the greater the number of resonance structure portions 18, the higher the intensity of reflected light. The plurality of resonance structures 18 may include resonance structures 18 having the same structure period Pk and resonance structures 18 having different structure periods Pk. According to such a configuration, it is possible to finely adjust the colors of reflected light and transmitted light emitted from the pixel 10.

  In manufacturing the pixel 10 including three or more resonance structures 18, the base material 11 and the concavo-convex structure layer 20 of the concavo-convex structure 31 are formed from a material that can peel the base material 11 from the concavo-convex structure layer 20. Then, after the two concavo-convex structures 31 are joined by the low refractive index material, one of the base materials 11 is peeled off, and the exposed concavo-convex structure layer 20 and the other concavo-convex structure 31 further form a low refractive index material. By repeating the sandwiching and joining, the pixel 10 having six or more sub-wavelength gratings is formed.

As described above, according to the second embodiment, in addition to the effects (1) and (3) to (8) of the first embodiment, the following effects can be obtained.
(9) According to the configuration in which the pixel 10 includes the plurality of resonance structures 18 arranged in the first direction, since the pixel 10 includes four or more lattice regions 13 and 15, the reflected light emitted from the pixel 10 It is possible to further increase the wavelength selectivity and to increase the degree of freedom in adjusting the wavelength range included in the reflected light and transmitted light. Therefore, the visibility of the image formed by the display body 100 can be increased, and the degree of freedom in adjusting the hue of the image visually recognized by the display body 100 can be increased.

  (10) According to the configuration in which the structural period Pk of the first resonant structure 18A and the structural period Pk of the second resonant structure 18B are different from each other, resonance occurs in each of the lattice regions 13 and 15 of the first resonant structure 18A. The wavelength range of light that causes resonance and the wavelength range of light that causes resonance in each of the lattice regions 13 and 15 of the second resonance structure 18B are different from each other. Therefore, when light is incident on the pixel 10, the pixel 10 has light of the first wavelength region strengthened by the lattice regions 13 and 15 of the first resonance structure 18A and the second resonance structure 18B. Reflected light including the light in the second wavelength region strengthened by the grating regions 13 and 15 is emitted. In addition, in the wavelength range included in the incident light of the pixel 10, light in the wavelength range excluding the first wavelength range and the second wavelength range emitted as the reflected light is emitted from the pixel 10 as transmitted light. . Therefore, in the pixel 10, it is possible to increase the wavelength range included in the reflected light while increasing the intensity of the reflected light, and to narrow the wavelength range included in the transmitted light. Therefore, the degree of freedom in adjusting the hue observed as reflected light or transmitted light can be increased by setting the grating period of the sub-wavelength gratings included in each of the resonance structures 18A and 18B. It is possible to increase the degree of freedom in adjusting the hue of a visually recognized image.

  (11) In each pixel 10A, 10B, 10C, in a configuration in which the combination of the structural period Pk of the first resonant structure 18A and the structural period Pk of the second resonant structure 18B is different from each other, the first pixel 10A and the second The pixel 10B and the third pixel 10C have different wavelength ranges of light emitted as reflected light, and different wavelength ranges of light emitted as transmitted light. Thereby, in each of the front surface reflection observation and the back surface transmission observation, the first display region 110A, the second display region 110B, and the third display region 110C appear to have different hue colors. According to such a configuration, the degree of freedom in adjusting the hue of the image visually recognized in the front surface reflection observation and the rear surface transmission observation is increased.

  (12) The pixel 10 is formed by facing two concavo-convex structures 31 so that the high refractive index layers 21 face each other and filling a region between the two concavo-convex structures 31 with a low refractive index material. The According to this, the pixel 10 provided with the some resonance structure part 18 can be formed easily. Therefore, the display body 100 can be easily manufactured.

(Third embodiment)
With reference to FIG. 14 and FIG. 15, 3rd Embodiment of the display body and the manufacturing method of a display body is described. The third embodiment differs from the second embodiment in the arrangement direction of the sub-wavelength gratings in the two resonance structures. Below, it demonstrates centering on the difference between 3rd Embodiment and 2nd Embodiment, about the structure similar to 2nd Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. 14 and 15 are diagrams showing a part of the pixel 10, and in order to make the structure of the pixel 10 easy to understand, the part is made of a high refractive index material and a low refractive index material. The dots are shown with dots having different densities.

[Pixel configuration]
As shown in FIG. 14, the pixel 10 included in the display body of the third embodiment includes two resonance structures 18 </ b> A and 18 </ b> B that are adjacent to each other in the first direction, as in the second embodiment. However, in the third embodiment, the element portions included in the lattice regions 13 and 15 of the first resonance structure portion 18A, that is, the extending directions of the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b, respectively. The extending directions of the element portions of the lattice regions 13 and 15 of the second resonance structure portion 18B are different from each other. That is, the direction in which the element portions are arranged in the lattice regions 13 and 15 is different for each resonance structure portion 18. In other words, the arrangement direction of the sub-wavelength gratings included in the first resonance structure 18A is different from the arrangement direction of the sub-wavelength gratings included in the second resonance structure 18B.

  The patterns of the four sub-wavelength gratings included in the pixel 10 match each other, the periods P1 and P2 are all equal, the high element widths Dh1 and Dh2 are all equal, and the region thickness T1 is the same in the resonance structures 18A and 18B. , T2 are all equal.

  FIG. 15 is a diagram in which the pixel 10 shown in FIG. 14 is divided into regions that extend in the direction along the surface of the substrate 11. FIG. 15 is a diagram for easy understanding of the arrangement of the element portions in the two resonance structure portions 18A and 18B, and the boundaries of the regions divided in FIG. It does not indicate the boundary of the structure.

  As shown in FIG. 15, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b of the first resonance structure portion 18A extend along the second direction and are arranged along the third direction. On the other hand, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b of the second resonance structure portion 18B extend along the third direction and are arranged along the second direction. That is, the extending direction of each element part included in the first resonance structure 18A is orthogonal to the extending direction of each element included in the second resonance structure 18B. In other words, the angle formed by the sub-wavelength grating arrangement direction of the first resonance structure 18A and the sub-wavelength grating arrangement direction of the second resonance structure 18B is 90 °.

[Action of display body]
When the sub-wavelength grating is composed of the high refractive index portions 13a and 15a extending in a band shape in one direction, in each of the grating regions 13 and 15, the light polarized in a specific direction undergoes multiple reflections and causes resonance. It is emitted as reflected light. The specific direction depends on the arrangement direction of the sub-wavelength gratings. The first resonance structure portion 18A and the second resonance structure portion 18B have different sub-wavelength grating arrangement directions, so that the lattice regions 13 and 15 of the first resonance structure portion 18A and the lattice regions of the second resonance structure portion 18B 13 and 15 are different from each other in the polarization direction of the light that is multiply reflected. Therefore, according to the pixel 10 of the third embodiment, the reflected light is efficiently emitted with respect to the incident light including the polarization components in various directions, so that the intensity of the reflected light is further increased.

  Incident light on the display body 100 is often light including polarization components in various directions, such as general illumination and sunlight. Therefore, with the configuration including the pixel 10 of the third embodiment, the sharpness and brightness of the colors visually recognized in the display regions 110A, 110B, and 110C are improved in the display body 100 that is observed under external light. High effect is obtained.

[Manufacturing method of display body]
As in the second embodiment, the pixel 10 according to the third embodiment includes two concavo-convex structures 31, which are structures including the base material 11, the concavo-convex structure layer 20, and the high-refractive index layer 21. 21 are formed so as to face each other, and a region between the two concavo-convex structures 31 is filled with a low refractive index material. Here, in the third embodiment, the extending direction of the high refractive index layer 21 in one uneven structure 31 and the extending direction of the high refractive index layer 21 in the other uneven structure 31 are orthogonal to each other. The concavo-convex structure 31 is faced and bonded by a low refractive index material.

  The pixel 10 may include three or more resonance structures 18 arranged in the first direction, and the plurality of resonance structures 18 may include resonance structures 18 in which the extending directions of the element parts are different from each other. That's fine. Such a pixel 10 includes an even number, that is, 2n (n is an integer of 3 or more) sub-wavelength gratings, and is 2m−1th (m is an integer of 1 to n) from a position close to one base material 11. In the wavelength grating and the 2m-th sub-wavelength grating, the arrangement directions are the same, and the grating periods are the same. In other words, the pixel 10 has a structure in which pairs of sub-wavelength gratings having the same arrangement direction and the same grating period are arranged in the first direction, and these sub-wavelength gratings are embedded in a low refractive material.

  According to such a configuration, the polarization responsiveness of the pixel 10 is improved by setting the arrangement direction of the sub-wavelength gratings for each resonance structure 18 or setting the number of resonance structures 18 having the same arrangement direction of the sub-wavelength gratings. It can also be adjusted. The plurality of resonance structures 18 may include resonance structures 18 having different sub-wavelength grating patterns.

  In manufacturing the pixel 10 including three or more resonance structures 18, the base material 11 and the concavo-convex structure layer 20 of the concavo-convex structure 31 are formed from a material that can peel the base material 11 from the concavo-convex structure layer 20. Then, after the two concavo-convex structures 31 are joined by the low refractive index material, one of the base materials 11 is peeled off, and the exposed concavo-convex structure layer 20 and the other concavo-convex structure 31 further form a low refractive index material. By repeating the sandwiching and joining, the pixel 10 having six or more sub-wavelength gratings is formed.

As described above, according to the third embodiment, in addition to the effects (1), (3) to (8) of the first embodiment and (9), (12) of the second embodiment, the following effects are obtained. It is done.
(13) Since the extending direction of the element part included in the first resonance structure 18A and the extending direction of the element part included in the second resonance structure 18B are different from each other, the lattice regions 13 and 15 of the first resonance structure 18A are different. In the grating regions 13 and 15 of the second resonance structure 18B, light polarized in different directions among the light included in the incident light causes resonance and is emitted from the resonance structures 18 respectively. Therefore, since the reflected light is efficiently emitted with respect to the incident light including polarization components in various directions, the intensity of the reflected light is further increased. Therefore, in the display body 100 that is observed under external light including polarization components in various directions, a high effect of improving the vividness and brightness of colors visually recognized in the display regions 110A, 110B, and 110C can be obtained. In addition, forgery difficulty and design are further enhanced.

  (14) In the configuration in which the extending direction of the element portion included in the first resonance structure portion 18A and the extending direction of the element portion included in the second resonance structure portion 18B are orthogonal to each other, incident light including polarization components in various directions Reflected light is emitted more efficiently than light. Further, the design and manufacture of the pixel 10 are easy.

[Modification]
The above embodiments can be implemented with the following modifications.
In the resonance structure portion 18 of the pixel 10 manufactured by the manufacturing method of each of the above embodiments, the second low refractive index portion 15b is located above the first high refractive index portion 13a, and the first low refractive index portion 13b. The second high-refractive index portion 15a is located on the top of the.

  That is, the arrangement pattern of the first high refractive index portion 13a matches the arrangement pattern of the second low refractive index portion 15b, and the arrangement pattern of the first low refractive index portion 13b is the same as the second high refractive index portion 15a. It matches the pattern of arrangement. In order to match the wavelength range of light that causes resonance in the first grating region 13 with the wavelength range of light that causes resonance in the second grating region 15, the first grating region 13, the second grating region 15, In which the grating periods of the sub-wavelength gratings coincide with each other, and the volume ratio of the plurality of first high refractive index portions 13a in the first grating region 13 and the volume of the plurality of second high refractive index portions 15a in the second grating region 15. The ratio needs to match.

  Satisfying such a condition is that each of the first high refractive index portion 13a, the first low refractive index portion 13b, the second high refractive index portion 15a, and the second low refractive index portion 15b as in the above embodiments. The element portions have the same shape extending in a band in one common direction, and the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b extend in the lattice regions 13 and 15, respectively. A configuration that is alternately arranged in a direction orthogonal to the direction is easy.

  However, as long as the above conditions are satisfied, each element portion may have a shape different from the shape extending in a strip shape. For example, as shown in FIG. 16, each of the first high refractive index portion 13a, the first low refractive index portion 13b, the second high refractive index portion 15a, and the second low refractive index portion 15b is in the first direction. It has the same rectangular shape such as a square when viewed from the direction along the direction, and in each of the grating regions 13 and 15, the high refractive index portions 13a and 15a and the low refractive index portions 13b and 15b are in the second direction and the third direction. The configuration may be arranged alternately along each direction. In such a case, as shown in FIG. 17, in the concavo-convex structure layer 20, the convex portions 20 b and the concave portions 20 c are alternately arranged along each of two directions orthogonal to each other. 20c has the same rectangular shape such as a square.

  According to the configuration shown in FIG. 16, even in one resonance structure 18, reflected light is efficiently emitted with respect to incident light including polarization components in various directions. Enhanced.

  In each of the above embodiments, the display body 100 has been illustrated with a configuration including the three types of pixels 10A, 10B, and 10C as the pixels 10, but the number of types of the pixels 10 that emit reflected light having different wavelengths is particularly limited. Instead, the number of types of pixels 10 may be one or four or more. That is, the number of display areas included in the display body 100, that is, the number of areas exhibiting different hue colors is not particularly limited.

  The display body 100 has a region having a configuration different from that of the pixel 10 of each embodiment, for example, a region having a structure in which only a flat layer made of a low refractive index material is stacked on the substrate 11. Also good.

  In the above embodiments, pixels are exemplified as display elements. However, the display elements are not limited to pixels that are the minimum unit of repetition for forming a raster image, but are regions that are connected with anchors for forming a vector image. It may be.

[Example]
The display body and the manufacturing method thereof described above will be described using specific examples.
<Manufacture of display body>
First, a mold which is an intaglio used in the optical nanoimprint method was prepared. Specifically, since light having a wavelength of 365 nm was used as light to be irradiated in the optical nanoimprint method, synthetic quartz that transmits light having this wavelength was used as a mold material. In forming the mold, first, a film made of Cr was formed on the surface of the synthetic quartz substrate by a sputtering method, and an electron beam resist pattern having a sub-wavelength grating pattern was formed on the Cr film by an electron beam lithography method. The sub-wavelength grating pattern is a pattern in which strip portions extending in one direction are arranged at equal intervals. The resist used was a positive type, and the film thickness was 150 nm.

  A pattern drawn with an electron beam is a pattern in which four types of sub-wavelength grating patterns are arranged. This pattern is schematically shown in FIG. The first pattern SP1 is a pattern in which band-shaped portions are arranged in the X direction with a period of 360 nm in a square region having a side of 3 cm. The second pattern SP2 is a pattern in which a band-shaped portion is arranged in a Y direction perpendicular to the X direction at a period of 360 nm in a square region having a side of 3 cm. The third pattern SP3 is a pattern in which band-like portions are arranged in the X direction with a period of 396 nm in a square region having a side of 3 cm. The fourth pattern SP4 is a pattern in which band-shaped portions are arranged in the Y direction with a period of 396 nm in a square region having a side of 3 cm.

  Next, the Cr film in the region exposed from the resist was etched by plasma generated by applying a high frequency to a mixed gas of chlorine and oxygen. Subsequently, the synthetic quartz substrate in the region exposed from the resist and the Cr film was etched by a plasma generated by applying a high frequency to hexafluoroethane gas. The depth of the synthetic quartz substrate etched by this was 200 nm. The remaining resist and Cr film were removed, and OPTOOL HD-1100 (manufactured by Daikin Industries) was applied as a release agent to obtain a mold in which the four sub-wavelength grating patterns were formed.

Next, an ultraviolet curable resin was applied in the region where the four sub-wavelength grating patterns were formed on the mold, and the mold surface was covered with a polyethylene terephthalate film subjected to an easy adhesion treatment. The UV curable resin is spread using a roller so as to spread over the entire surface in the region where the sub-wavelength grating pattern is formed, irradiated with 365 nm UV light to cure the UV curable resin, and then the polyethylene terephthalate film from the mold. Was peeled off. Thereby, the sub-wavelength grating pattern obtained by inverting the four sub-wavelength grating patterns is formed on the surface of the ultraviolet curable resin, and the uneven structure layer made of the ultraviolet curable resin and the base material that is a polyethylene terephthalate film are formed. A laminate was obtained. A region where each of the four sub-wavelength grating patterns is formed corresponds to a pixel portion. The above process was repeated to produce two laminates of the concavo-convex structure layer and the substrate. Note that the irradiation amount of ultraviolet light at 365 nm was 50 mJ / cm ² .

Next, a high refractive index layer made of TiO ₂ was formed by forming a TiO ₂ film having a thickness of 100 nm on the surfaces of the two laminates using a vacuum deposition method. Subsequently, an ultraviolet curable resin is applied to a region where the sub-wavelength grating pattern on the surface of one of the two laminated bodies is located, and the other laminated body is applied to the coated ultraviolet curable resin. The two laminates were opposed to each other so that the surfaces were in contact with each other and the regions where the sub-wavelength grating patterns with the same period were located overlapped. The ultraviolet curable resin was extended using a roller so as to spread over the entire surface in the region where the sub-wavelength grating pattern was located, and the ultraviolet curable resin was cured by irradiating with 365 nm ultraviolet rays to form an embedded layer. Thereby, the display body of the Example was obtained. Note that the irradiation amount of ultraviolet light at 365 nm was 50 mJ / cm ² .

<Evaluation of display>
When reflection spectroscopy measurement was performed on the display body of the example, a reflection spectrum having a center wavelength of about 530 nm was observed for a pixel having a sub-wavelength grating with a period of 360 nm, and a pixel having a sub-wavelength grating having a period of 396 nm was centered at about 620 nm. A reflection spectrum having a wavelength was observed.

  DESCRIPTION OF SYMBOLS 10 ... Pixel, 10A ... 1st pixel, 10B ... 2nd pixel, 10C ... 3rd pixel, 11 ... Base material, 12 ... 1st low refractive index area | region, 13 ... 1st grating | lattice area | region, 13a ... 1st high refractive index Part, 13b ... first low refractive index part, 14 ... second low refractive index region, 15 ... second grating region, 15a ... second high refractive index part, 15b ... second low refractive index part, 16 ... third low Refractive index region, 17 ... third high refractive index portion, 18 ... resonance structure portion, 18A ... first resonance structure portion, 18B ... second resonance structure portion, 20 ... uneven structure layer, 20a ... flat portion, 20b ... convex portion 20c ... concave part, 21 ... high refractive index layer, 21a ... first layered part, 21b ... second layered part, 22 ... embedded layer, 31 ... concave structure, 100 ... display body, 100F ... front surface, 100R ... back surface, 110 ... display area, 110A ... first display area, 110B ... second display area, 110C ... third display area

Claims (14)

A display body comprising a display element made of a material that transmits incident light and having a front surface and a back surface,
The display element is:
A plurality of first high refractive index portions constituting the first sub-wavelength grating, and a plurality of first low refractive index portions having a lower refractive index than the first high refractive index portion, along the surface First lattice regions in which the first high refractive index portions and the first low refractive index portions are alternately positioned in a direction;
A plurality of second high-refractive-index parts that are made of the same material as the first high-refractive-index part and constitute a second sub-wavelength grating; 2 low refractive index portions, and a second grating region in which the second high refractive index portions and the second low refractive index portions are alternately positioned in a direction along the surface;
A first low-refractive index region, a second low-refractive index region, and a third low-refractive index each having a lower refractive index than each of the average refractive index of the first grating region and the average refractive index of the second grating region. A rate area, and
The first lattice region is sandwiched between the first low refractive index region and the second low refractive index region in the thickness direction of the display body,
The second lattice region is sandwiched between the second low refractive index region and the third low refractive index region in the thickness direction of the display body,
The grating period of the first sub-wavelength grating and the grating period of the second sub-wavelength grating are equal to each other,
The volume ratio of the plurality of first high refractive index portions in the first grating region is the same as the volume ratio of the plurality of second high refractive index portions in the second grating region,
When viewed from the direction facing the surface, the first high refractive index portion and the second low refractive index portion overlap, and the second high refractive index portion and the first low refractive index portion overlap. body. The display body includes a plurality of display elements, and the plurality of display elements include a first display element and a second display element.
The display body includes a first display area in which the first display element is located and a second display area in which the second display element is located, as viewed from the direction facing the surface.
The grating periods of the first sub-wavelength grating and the second sub-wavelength grating in the first display element and the grating periods of the first sub-wavelength grating and the second sub-wavelength grating in the second display element are mutually The display body according to claim 1. A portion constituted by the first grating region, the second grating region, the first low refractive index region, the second low refractive index region, and the third low refractive index region is a resonance structure portion,
The display body according to claim 1, wherein the display element includes a plurality of the resonance structures arranged in a thickness direction of the display body. The plurality of resonance structure parts include a first resonance structure part and a second resonance structure part, and have a grating period of the first sub-wavelength grating and the second sub-wavelength grating of the first resonance structure part. The display body according to claim 3, wherein a first structure period and a second structure period that is a grating period of the first sub-wavelength grating and the second sub-wavelength grating included in the second resonance structure unit are different from each other. . The display body includes a plurality of display elements, and the plurality of display elements include a first display element and a second display element.
The display body includes a first display area in which the first display element is located and a second display area in which the second display element is located, as viewed from the direction facing the surface.
The combination of the first structure period and the second structure period in the first display element and the combination of the first structure period and the second structure period in the second display element include the first structure period. The display body according to claim 4, wherein at least one of the second structural period and the second structural period is different. In each of the plurality of resonant structure portions, the plurality of first high refractive index portions, the plurality of first low refractive index portions, the plurality of second high refractive index portions, and the plurality of second low refractive index portions. The element part which is each of the parts has a shape extending in a band shape in one direction,
The plurality of resonance structures include a first resonance structure and a second resonance structure,
The display body according to claim 3, wherein a direction in which the element part included in the first resonance structure part extends and a direction in which the element part included in the second resonance structure part extends are different from each other. The direction in which the element portion of the first resonance structure portion extends and the direction of extension of the element portion of the second resonance structure portion are directions along the surface and are orthogonal to each other. Display body of description. The first low refractive index region, the first low refractive index portion, and a portion adjacent to the first low refractive index portion in the second low refractive index region are one continuous structure. A first structure that is
The third low refractive index region, the second low refractive index portion, and a portion adjacent to the second low refractive index portion in the second low refractive index region are one continuous structure. The display body according to claim 1, wherein the display body is a second structure body. The refractive index difference between the first structure and the first high refractive index portion and the second high refractive index portion is greater than 0.2,
The display body according to claim 8, wherein a difference in refractive index between the second structure, the first high refractive index portion, and the second high refractive index portion is greater than 0.2. The material constituting the first structure is one of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin,
The material constituting the second structure is one of an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin,
The display body according to claim 8 or 9, wherein a material constituting the first high refractive index portion and the second high refractive index portion includes an inorganic compound. The second low refractive index region has a third high refractive index portion made of the same material as the first high refractive index portion and the second high refractive index portion,
The third high refractive index portion is formed between the end portions of the first high refractive index portion and the second high refractive index portion that are adjacent to each other when viewed from the direction facing the surface. The display body as described in any one of Claims 8-10 extended along the thickness direction. A method of manufacturing a display body including a display element made of a material that transmits incident light, the step of manufacturing the display element,
A plurality of convex portions arranged in a sub-wavelength period on a surface of the layer made of the first low refractive index material, and concave portions alternately arranged with the convex portions along a direction in which the plurality of convex portions are arranged; Forming a concavo-convex structure layer having the convex portions and the concave portions by forming a plurality of concave portions having an area equal to an area of the plurality of convex portions when viewed from the facing direction;
A high refractive index layer having a thickness smaller than the height of the convex portion is formed on the surface of the concavo-convex structure layer using a high refractive index material having a higher refractive index than the first low refractive index material. 2 steps, wherein the high refractive index layer includes a first sub-wavelength grating located on the concave portion and a second sub-wavelength located on the convex portion and having the same grating period as the first sub-wavelength grating. A second step of forming a layer comprising a wavelength grating;
By forming a buried layer made of a second low refractive index material having a refractive index lower than that of the high refractive index material on the surface of the structure consisting of the uneven structure layer and the high refractive index layer, the structure A third step of filling the second sub-wavelength grating with the unevenness of the second sub-wavelength grating with the second low refractive index material. In the first step, an intaglio is pressed against a coating layer made of a resin that is the first low-refractive index material, and after the resin is cured, the intaglio is released to transfer the unevenness of the intaglio to the resin. By forming the concavo-convex structure layer,
In the second step, the high refractive index layer is formed using a material containing an inorganic compound as the high refractive index material,
The said 3rd process WHEREIN: The resin which is the said 2nd low refractive index material is applied to the surface of the said structure, and the said embedded layer is formed by hardening the applied resin. Manufacturing method of display body. In the third step, the two structures are opposed so that the high-refractive index layers face each other, and a region between the two structures is filled with the second low-refractive index material. The method for manufacturing a display body according to claim 12 or 13, wherein a layer is formed.