WO2015079652A1 - Display body and method for manufacturing same - Google Patents

Abstract

Provided is a display body having strong design aesthetics using structural color developing. A display body including a substrate, a multilayered laminate formed on the substrate surface, and a fine uneven layer formed on the multilayered laminate surface, wherein: the multilayered laminate has two or more layers; at least the multilayered laminate and the fine uneven layer transmit light of a prescribed wavelength region; the layers constituting the multilayered laminate are composed of materials having different refractive indices than adjacent layers in relation to light having a wavelength within the prescribed wavelength region; the materials constituting the layers that constitute the multilayer laminate and the fine uneven layers each have an optical film thickness, represented by the product of the refractive index thereof and the physical film thickness, that is less than 7/4 of the shortest wavelength in the prescribed wavelength region; and the physical film thickness of the fine uneven layer is partially reduced in the fine uneven layer, thereby forming an irregularly structured body including convex parts and concave parts having a height difference that is equal to or less than the physical film thickness.

Description

Display body and manufacturing method of display body

The present invention relates to a display body whose color tone changes according to a change in observation angle using structural coloring, and a manufacturing method thereof.

In recent years, biomimetic technology that artificially reproduces the high functionality found in the epidermis of animals and plants has attracted attention. For example, the structural coloration typified by Morpho butterfly scales and iridescent epidermis is not the coloration associated with the energy transition of the electronic state of molecules such as dyes and pigments, but the coloration caused by the action of optical phenomena such as light diffraction, interference, and scattering. It is a phenomenon.

Most of the structural coloration is based on multilayer film interference that occurs due to interference of reflected light at each interface of multilayer laminates having different refractive indexes. Multilayer film interference occurs when reflected light generated at each interface of the laminate interferes with each other, and an optical path difference caused by each layer is an important factor.

This optical path difference depends on the refractive index of the constituent material in addition to the physical film thickness of each layer, and also changes depending on the incident angle. Therefore, the structural color development due to multilayer film interference is characterized in that the color tone of the reflected light changes depending on the incident angle of light.

By utilizing the dependency of the color tone on the incident angle, for example, as described in Patent Document 1, a multilayer laminate having a structural color due to multilayer film interference is provided on a black layer, and the reflection color changes depending on the viewing angle. A copy protection printing material has been invented.

Further, for example, by forming a non-uniform fine concavo-convex structure on the surface of a base material that forms a multilayer laminate having structural color development due to multilayer film interference, as described in Patent Document 2, the incident angle dependence of color tone can be reduced. Controlled color bodies have been invented.

These inventions enable unique color expressions in which the color tone changes according to the change in the observation angle, making it possible to manufacture a display body with high design.

JP 2013-122567 A Japanese Patent No. 4228058

However, the color tone of the reflected light by the multilayer laminate as described above is basically determined by the material constituting each layer of the laminate and the physical film thickness, and the color tone change due to the change in observation angle is monotonous. End up.

Although it is possible to modulate the color tone and reflectivity by forming a non-uniform fine concavo-convex structure on the base material that forms the multilayer laminate, the color tone change of reflected light due to the change in observation angle is moderated. The main effect is to increase the reflectance at a specific angle, and when the structure of the multi-layer laminate is the same, it is difficult to express various color tone changes.

Therefore, for example, in the case where an attempt is made to manufacture a display body with high design characteristics in which the change in the color tone of reflected light due to a change in the observation angle varies depending on the pixel region by utilizing structural coloration due to multilayer film interference, for each pixel region It is necessary to form a multilayer laminate with different constituent materials and physical film thickness.

In that case, the process of masking areas other than the areas having the same color change and the process of forming the multilayer laminate must be repeated as many times as necessary, which complicates the process.

The present invention has been made to solve such problems, and has a simple design and a display body having a high design property such that a change in color tone of reflected light due to a change in observation angle varies depending on a pixel region. An object of the present invention is to provide a manufacturing method thereof.

One aspect of the present invention is a display body including a base material, a multilayer laminate formed on the surface of the base material, and a fine uneven layer formed on the surface of the multilayer laminate, wherein the multilayer laminate is a laminate of two or more layers. And at least the multilayer laminate and the fine concavo-convex layer are transparent to light of a predetermined wavelength region, and each layer constituting the multilayer laminate is adjacent to the adjacent layer within the predetermined wavelength region. It is composed of materials that have different refractive indices with respect to light of the wavelength, and each layer that constitutes the multilayer laminate and the material that constitutes the fine concavo-convex layer is an optical represented by the product of the respective refractive index and physical film thickness. The film thickness is less than 7/4 times the shortest wavelength in the predetermined wavelength region, and the fine concavo-convex layer has a height difference below the physical film thickness by partially reducing the physical film thickness of the fine concavo-convex layer. It is a display body in which a concavo-convex structure including a convex portion and a concave portion is formed.

Also, a one-dimensional diffractive structure composed of a linear concavo-convex structure with a constant period or a two-dimensional diffractive structure composed of a lattice-shaped concavo-convex structure with a constant period may be formed on the surface of the fine concavo-convex layer.

Further, it is preferable that the refractive index for light having a wavelength within the wavelength region of the material constituting the fine uneven layer is larger than the refractive index for light having the wavelength of the material constituting the uppermost layer of the multilayer laminate.

In addition, between the uppermost layer of the multilayer laminate and the fine concavo-convex layer, it is made of a material having a refractive index larger than that of the material constituting the fine concavo-convex layer, with a physical film thickness and refractive index. The optical film thickness, which is the product of the above, has a waveguiding layer that is less than 7/4 times the shortest wavelength in the wavelength region. It may be equal to the film thickness.

In addition, the wavelength region is a visible light wavelength region, and a plurality of pixel regions arranged on a matrix having at least one side of 10 μm or more are formed on the surface of the fine concavo-convex layer, and each pixel region has a structural period of 200 nm or more and A first one-dimensional diffractive structure having a linear concavo-convex structure of 800 nm or less, in which the linear concavo-convex structure is arranged in a first direction, and a linear concavo-convex structure having a structure period of 200 nm or more and 800 nm or less. And a second one-dimensional diffractive structure in which linear concavo-convex structures are arranged in a second direction different from the first direction, and a lattice-like concavo-convex structure having a structural period of 200 nm or more and 800 nm or less, At least one of the two-dimensional diffractive structures may be formed by arranging the lattice-shaped concavo-convex structure in the first direction and the second direction.

Further, the base material, each layer of the multilayer laminate, and the fine uneven layer are preferably made of a material having an extinction coefficient of 0.1 or less with respect to light in the visible light wavelength region.

In addition, the base material, each layer of the multilayer laminate, the fine uneven layer, and the waveguide layer are made of a material having a refractive index with respect to light having a wavelength in the visible light wavelength region of 1.3 or more and 2.6 or less. The refractive index difference between adjacent layers is preferably at least 0.05.

Another aspect of the present invention is a step of forming a multilayer laminate having transparency to visible light wavelength region light on the substrate surface and different refractive indexes in adjacent layers by sequentially laminating each layer. And a step of applying a photocurable resin to the surface of the multilayer laminate, and a step of forming a desired uneven shape on the photocurable resin by an optical nanoimprint method.

Further, it is preferable that the refractive index of the light curable resin with respect to light having a wavelength in the visible light wavelength region is larger than the refractive index with respect to the visible light wavelength region of the material constituting the surface of the multilayer laminate.

In addition, the manufacturing method of the display body includes a step of preparing a base material, and a laminate that has transparency to light having a wavelength in the visible light region on the surface of the base material and has a different refractive index in each adjacent layer. A step of sequentially laminating each layer, a step of forming a waveguiding layer on the surface of the multilayer laminate, and a light having a wavelength in the visible light region than the material constituting the waveguiding layer on the surface of the waveguiding layer. You may include the process of apply | coating photocurable resin with a small refractive index, the process of forming desired uneven | corrugated shape in photocurable resin by the photo nanoimprint method, and the process of removing a residual film by plasma exposure.

In addition, the manufacturing method of the display body includes a step of preparing a base material, and a laminate that has transparency to light having a wavelength in the visible light region on the surface of the base material and has a different refractive index in each adjacent layer. Including a step of sequentially laminating and forming each layer, a step of applying a thermoplastic resin layer to the surface of the uppermost layer of the multilayer laminate, and a step of forming a desired uneven shape on the thermoplastic resin layer by a thermal nanoimprint method. Good.

Further, it is preferable that the refractive index of the thermoplastic resin layer with respect to light having a wavelength in the visible light region is larger than the refractive index with respect to light having a wavelength of the material constituting the outermost surface of the multilayer laminate.

In addition, the method of manufacturing the display body includes a step of preparing a base material, and a laminated body that is transparent to light having a wavelength in the visible light wavelength region on the surface of the base material and has a different refractive index in each adjacent layer. Are formed by sequentially laminating each layer, a step of forming a waveguiding layer on the surface of the multilayer laminate, and a wavelength within the visible light wavelength region than the material constituting the waveguiding layer on the surface of the waveguiding layer. You may include the process of apply | coating the thermoplastic resin layer with a small refractive index with respect to light, the process of forming a desired uneven | corrugated shape in a thermoplastic resin layer by a thermal nanoimprint method, and the process of removing a residual film by plasma exposure.

In the present invention, a fine concavo-convex layer having a region in which a one-dimensional or two-dimensional diffractive structure is formed is provided on the surface of a multilayer laminate that is structurally colored by multilayer film interference, and the fine concavo-convex layer further relates to multilayer film interference. The film thickness was designed to be As a result, it is possible to obtain a display body in which reflected light exhibits a unique color tone change due to a change in observation angle using multilayer film interference and diffraction phenomenon, thereby improving the design of the design displayed by the display body. An effect is obtained.

In addition to the effect, the effect of guided mode resonance can be given by designing the structure of the display body optimally. For this reason, it becomes possible to produce the effect of further improving the design of the display object.

FIG. 1 is a schematic view of a cross section of a display body according to a first embodiment of the present invention. FIG. 2 is a schematic view of a cross section of a display body according to the second embodiment of the present invention. FIG. 3 is a schematic view of a cross section of a display body according to the third embodiment of the present invention.

Hereinafter, first to third embodiments of the present invention will be described with reference to the drawings. In the present invention, the wavelength region of light is not particularly limited. For example, in the case of a display body that can be visually observed by a person, the light wavelength region is observed in the visible light wavelength region, or by an ultraviolet camera or an infrared camera. In such a case, the wavelength region can be limited to the corresponding ultraviolet region or infrared region. Hereinafter, in the first, second, and third embodiments, a display body that can be visually observed by a person will be described.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of a cross-section of a display body 1 according to a first embodiment of the present invention. A multilayer laminate 21 is formed on a base material 11, and on the multilayer laminate 21, A fine uneven layer 31 is formed.

In the present invention, the material of the base material 11 is not particularly limited. However, in order to perform color expression only by structural color development due to multilayer film interference, a material having high transparency in the visible light wavelength region is preferable. Examples thereof include synthetic quartz glass and polyethylene terephthalate. In the first embodiment, the base material 11 is a synthetic quartz glass substrate.

The multilayer laminate 21 is formed by laminating materials having different refractive indexes. As a material for forming each layer, the display body 1 needs to be transmissive to light in a wavelength region for displaying a design.

For example, as a material having high transparency with respect to the visible light wavelength region, for example, TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , Al ₂ O ₃ , SiO ₂ , Fe ₂ O ₃ , HfO ₂ , MgO, ZrO _{, SnO 2, Sb 2 O 3} , CeO 3, WO 3, PbO, In 2 O 3, CdO, BaTiO 3, ITO, LiF, BaF 2, CaF 2, MgF 2, AlF 3, CeF 3, ZnS, PbCl 2 An inorganic dielectric material such as an organic resin material such as an acrylic resin, a phenol resin, or an epoxy resin can be used. In addition, regarding the material constituting each layer of the multilayer laminate 21, since the reflection intensity at the interface increases as the difference in refractive index between adjacent layers increases, sufficient reflection intensity can be obtained even with a small number of layers. In the first embodiment of the present invention, the multilayer laminate 21 is a laminate of TiO ₂ and SiO ₂ .

An example of a method for forming the multilayer laminate 21 will be described. First, TiO ₂ is formed on the surface of the base material 11 made of synthetic quartz glass. As a film forming method, for example, a known method such as a vacuum evaporation method, sputtering, or an atomic layer deposition method can be used. Subsequently, SiO ₂ is formed on the surface of the formed TiO ₂ film. As a film forming method, for example, a known method such as a vacuum evaporation method, sputtering, or an atomic layer deposition method can be used. Perform deposition of TiO ₂ and SiO ₂ alternately to form a multilayer stack 21 and TiO ₂ and SiO ₂ are alternately laminated on the surface of the substrate 11. The number of layers to be stacked and the physical film thickness of each layer need to be designed so as to obtain a desired reflected light spectrum. When the material to be laminated is an organic compound material, a known coating method such as a spin coating method may be used.

In particular, regarding the physical film thickness, it is necessary to design the film thickness within an appropriate range in order to obtain a display body that effectively uses multilayer film interference. For example, when considering thin-film interference at normal incidence when each layer is replaced with a single layer, the refractive index n of the material constituting the layer, the physical film thickness d, and m are integers of 0 or more, and 2 × d = (m + 1 / 2) Light having a wavelength λ satisfying × λ / n is strengthened. When the physical film thickness of the thin film increases, there are many combinations of m and λ that satisfy the equation, and a plurality of wavelengths in the visible light wavelength region are strengthened, so that color recognition may become unclear. Since the same phenomenon occurs in multilayer film interference, it is necessary to select a suitable film thickness for each layer constituting the multilayer stack 21. For this reason, in the present invention including the first embodiment, the optical film thickness represented by the product of the refractive index n and the physical film thickness d of each layer of the laminate that structurally develops color by multilayer interference is the target wavelength region. It is preferably designed to be less than 7/4 times the shortest wavelength. Furthermore, in order to recognize a color clearly, it is more preferable that it is less than 5/4 times. In the first embodiment for a display body that can be visually observed by a person, the upper limit value of the optical film thickness of each layer forming the multilayer laminate 21 is visible light because it is for the visible light wavelength region. It is preferable to be less than 7/4 times the shortest wavelength in the wavelength region. On the other hand, the lower limit value of the optical film thickness can be set to a value satisfying n × d = λ / 4 with m = 0 in order to satisfy the expression for strengthening thin film interference. Therefore, even in the case of n × d <λ / 4, structural color development by multilayer film interference is possible, and therefore it is not limited in the present invention.

In the first embodiment, the film thickness of TiO ₂ is 160 nm, and the film thickness of SiO ₂ is 275 nm. Further, the number of layers to be laminated is 5 layers of TiO ₂ and 4 layers of SiO ₂ . Therefore, the uppermost layer of the multilayer laminate 21 is TiO ₂ . In the present specification, the term “film thickness” simply means a physical film thickness.

An example of a method for forming the fine uneven layer 31 will be described. After the multilayer laminate 21 is formed, the fine uneven layer 31 is formed on the multilayer laminate 21. The fine concavo-convex layer 31 also needs to be made of a material that is transparent to the target wavelength region, like the multilayer laminate 21. By making the optical film thickness, which is the product of the refractive index and the physical film thickness, of the fine uneven layer 31 less than 7/4 times the shortest wavelength in the visible light wavelength region in the same manner as each layer of the multilayer laminate 21, Structural coloration by multilayer film interference including the concavo-convex layer 31 can be realized, and a display body with high design can be obtained. Further, the refractive index of the material constituting the fine uneven layer 31 may be larger than the refractive index of the material constituting the uppermost layer of the multilayer laminate 21. The multilayer laminate 21 and the fine uneven layer 31 are preferably made of a material having an extinction coefficient of 0.1 or less with respect to visible light, for example.

Furthermore, the concavo-convex structure formed on the fine concavo-convex layer 31 is formed by partially reducing the physical film thickness of the fine concavo-convex layer 31 to form the concavo-convex, and is dimensioned so that incident light is diffracted. . For example, a one-dimensional diffractive structure composed of a linear concavo-convex structure having a constant period and a two-dimensional diffractive structure composed of a lattice-shaped concavo-convex structure having a constant period are suitable. By forming this structure, it is possible to obtain a display body 1 with higher design by utilizing the diffraction effect generated in the fine uneven layer 31. In this embodiment, since the concavo-convex structure is formed only in the fine concavo-convex layer 31, the height from the concave surface to the convex surface of the concavo-convex structure (H1 in FIG. 1) is the physical film of the fine concavo-convex layer 31. Thickness (H2) or less.

The structural period of the diffractive structure may be a structural period that diffracts light in the target wavelength region. For example, in the case of a display body that can be visually confirmed by a person, if the structure period is larger than the shortest wavelength in the visible light wavelength region, a change in color tone due to the diffraction effect is observed even when the display body is observed from the front. However, even when the structural period is smaller than the shortest wavelength in the visible light wavelength region, a diffraction phenomenon with respect to the visible light wavelength occurs by observing the display body from an oblique direction. Therefore, the structural period may be, for example, 200 nm or more and 800 nm or less. Since the diffraction effect varies depending on the structural period, a plurality of pixel regions are arranged on the surface of the fine concavo-convex layer 31 and the structural period is changed for each pixel, thereby enabling image display with various color tone changes. In addition, although it becomes possible to display a high-resolution image as the pixel area is fine, in the present invention, for example, one side is arranged on a matrix of 10 μm or more in order to make a display body that can be visually confirmed by a person. Let it be a pixel area.

In the first embodiment, the constituent material of the fine concavo-convex layer 31 is SiO ₂ and the film thickness of the fine concavo-convex layer 31 including the height of the concavo-convex structure is 300 nm. The structures to be formed are a two-dimensional diffractive structure composed of a lattice-like concavo-convex structure with a structure period of 700 nm and a one-dimensional diffractive structure composed of a linear concavo-convex structure with a structure period of 350 nm, and sandwiches a region where no fine structure is formed Form in each individual area. The height of the concave / convex pattern is 200 nm.

The method of forming a fine uneven layer 31, the material constituting the fine uneven layer 31 if an inorganic dielectric material such as SiO _2, for example, using known methods such as vacuum deposition or sputtering, atomic layer deposition Film formation process, etching mask manufacturing process using known methods such as charged particle beam exposure and nanoimprinting, pattern formation process using known methods such as plasma etching, plasma ashing and chemicals A mask removing process using a known method such as cleaning may be provided. Moreover, if the material which comprises the fine uneven | corrugated layer 31 is a photocurable resin or a thermoplastic resin, for example, it may be only a resin coating step and a fine structure forming step by a photo nanoimprint method or a thermal nanoimprint method. The formation process of the uneven | corrugated layer 31 can be simplified. Moreover, the refractive index with respect to the light of the wavelength of visible light wavelength region of the photocurable resin or thermoplastic resin constituting the fine uneven layer 31 is the refractive index with respect to the visible light wavelength region of the material constituting the surface of the multilayer laminate 21. Is preferably larger.

When a person visually observes the display body of the first embodiment, structural coloration due to green-yellow multilayer interference is observed in the vertical direction in the fine structure non-formation region, and the observation angle is moved in the horizontal direction. It is confirmed that the blue shift gradually. On the other hand, when a region where a two-dimensional diffractive structure having a lattice-like concavo-convex structure with a structure period of 700 nm is formed is observed from the vertical direction, structural color development different from that of a region without a fine structure is observed due to the diffraction effect. Further, the diffraction effect is emphasized by observing the display body by tilting, and a unique color tone change depending on the observation angle is observed. In addition, when a region in which a one-dimensional diffraction structure composed of a linear concavo-convex structure having a structural period of 350 nm is formed is observed from the vertical direction, a diffraction effect in the visible light wavelength region cannot be obtained. Similar structural color development is observed, but when the display body is tilted in the arrangement direction of the linear concavo-convex structure, a diffraction effect is obtained in the visible light wavelength region, and an inherent color tone change is observed. The change in color tone due to the formation of the one-dimensional diffractive structure naturally changes depending on the direction in which the display body is tilted. For example, when the one-dimensional diffractive structure having a different arrangement direction of 90 ° is formed in another region, the color is changed. It is also possible to add a changing effect in which the symbol displayed changes depending on the direction. Furthermore, a two-dimensional diffractive structure that is a lattice-shaped concavo-convex structure whose arrangement direction matches these one-dimensional diffractive structures may be formed. Various patterns can be configured by appropriately forming a plurality of one-dimensional diffractive structures having different arrangement directions as described above, or two-dimensional diffractive structures arranged in two arrangement directions among them. As described above, the multilayer laminated body 21 that expresses the structural color by multilayer film interference is formed on the substrate 1, and the fine uneven layer 31 is further formed, so that diffraction according to the diffraction structure formed on the fine uneven layer 31 is achieved. It is possible to obtain a display body 1 having a unique color tone change to which a phenomenon is given.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic view of a cross section of the display body 2 according to the second embodiment of the present invention. A multilayer laminate 22 is formed on the substrate 12, and the multilayer laminate 22 is A waveguide layer 42 is formed, and a fine uneven layer 32 is formed on the waveguide layer 42.

In the display body 2 of the second embodiment, by providing the waveguide layer 42, guided mode resonance by a one-dimensional diffractive structure formed in the waveguide layer 42 and the fine uneven layer 32 is used. The guided mode resonance occurs when the light diffracted by the one-dimensional diffractive structure satisfies the phase matching condition for propagating through the waveguide layer 42, and only the wavelength satisfying the guided mode resonance condition is incident. This is an optical phenomenon that reflects to the side. However, this guided mode resonance is most efficient when light is incident vertically, and the viewing angle at which the guided mode resonance can be obtained is very narrow.

In order to satisfy the waveguide mode resonance condition, the material used for the waveguide layer 42 is preferably selected from materials having higher refractive indexes than the outermost surface of the adjacent multilayer stack 22 and the fine uneven layer 32. The film thicknesses of the waveguide layer 42 and the fine uneven layer 32 are preferably limited to those in the first embodiment, and are designed to be optimum film thickness values that satisfy the waveguide mode resonance condition. That is, it is preferable that the optical film thickness, which is the product of the refractive index of the waveguide layer 42 and the physical film thickness, be less than 7/4 times the shortest wavelength in the visible light wavelength region. In the display body 2 of the second embodiment, the film thickness of the fine uneven layer 32 and the height of the uneven structure formed in the fine uneven layer 32 need to match. That is, it is preferable that the waveguide layer 42 is exposed in the recess.

Constraints on materials constituting the base material 12, the multilayer laminate 22, and the fine uneven layer 32 are the same as those in the first embodiment. Further, restrictions on the film thicknesses of the layers constituting the multilayer laminate 22 are the same as those in the first embodiment.

The method for forming the multilayer laminate 22 on the substrate 12 may be the same as that of the first embodiment. As for the waveguiding layer 42, if the constituent material is an inorganic dielectric material, a known method such as a vacuum deposition method, sputtering, or an atomic layer deposition method can be used. A known coating method such as a coating method can be used.

As a method for forming the fine uneven layer 32, the method for forming the fine uneven layer 31 in the first embodiment can be applied. However, since the film thickness of the fine concavo-convex layer 32 in the second embodiment is preferably equal to the height of the concavo-convex structure formed in the fine concavo-convex layer 32, for example, when forming the structure by plasma etching, Etching is preferably performed until the surface of the adjacent waveguide layer 42 is exposed. In this case, it is preferable that the material constituting the waveguide layer 42 is resistant to plasma for etching the fine uneven layer 32.

Further, as a method for forming the fine uneven layer 32, the optical nanoimprint method or the thermal nanoimprint method can be more preferably used. In this case, the surface of the waveguide layer 42 can be exposed in the concave portion by performing a residual film removal process using plasma. However, it is preferable that the material constituting the waveguide layer 42 is resistant to the plasma from which the remaining film is removed.

Further, as the structure formed in the fine concavo-convex layer 32, a one-dimensional diffractive structure composed of a linear concavo-convex structure with a constant period is preferable. The wavelength of reflected light due to guided mode resonance is determined by the structure period of the structure.

For example, the refractive index of the material constituting the uppermost layer of the multilayer laminate 22 is about 1.45, the refractive index of the material constituting the waveguide layer 42 is about 2.0, and the refractive index of the material forming the fine uneven layer 32. Is approximately 1.7 nm, the thickness of the waveguide layer 42 is approximately 100 nm, the thickness of the fine uneven layer 32 is approximately 150 nm, the structural period of the fine uneven layer 32 is approximately 265 nm, approximately 330 nm, and approximately 370 nm. A display body 2 in which a one-dimensional diffractive structure composed of a linear concavo-convex structure having a value obtained by dividing a convex dimension by a structure period of 0.45 is formed in each individual region across a region where a fine structure is not formed. Created and observed from the front. In this case, blue is reflected by guided mode resonance in a region having a structural period of about 265 nm, green in a region having a structural period of about 330 nm, and red in a region having a structural period of about 370 nm. A structural color different from the region is observed. Further, when the display body is observed with a certain angle tilted in the arrangement direction of the linear concavo-convex structure, the reflected light due to the waveguide mode resonance cannot be observed if the display body is tilted more than a certain angle. However, since the periodic structure of the structure formed in the fine uneven layer 32 is less than or equal to the visible light wavelength region, structural coloration by the multilayer laminate 22, the waveguide layer 42, and the fine uneven layer 32 is observed. However, as the inclination is increased, a diffraction phenomenon due to the one-dimensional diffractive structure acts, and a unique color change different from that in the structure non-formation region is observed in the structure formation region. As described above, it is possible to obtain the display body 2 having a unique color change in which waveguide mode resonance and the effect of the diffraction effect are imparted to the multilayer film interference. Each layer of the multilayer laminate 22, the fine concavo-convex layer 32, and the waveguide layer 42 are made of a material having a refractive index with respect to light in the visible light wavelength region of 1.3 or more and 2.6 or less, and are adjacent to each other. It is preferable that the refractive index difference of each layer is at least 0.05 or more.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a schematic cross-sectional view of the display body 3 according to the third embodiment of the present invention. A multilayer laminate 23 is formed on the base material 13, and a fine laminate is formed on the multilayer laminate 23. An uneven layer 33 is formed.

Also in the third embodiment, guided mode resonance is used as in the second embodiment. However, in the third embodiment, the waveguide layer 42 provided in the second embodiment is not provided, and the film thickness of the fine uneven layer 33 is set to the height of the structure formed in the fine uneven layer 33. By designing the thickness to be thick, the remaining film plays the role of the waveguide layer 42 provided in the second embodiment, and the display body 3 that can use guided mode resonance can be obtained.

In order to use guided mode resonance, the material constituting the fine uneven layer 33 needs to be selected from materials having a higher refractive index than the material constituting the uppermost layer of the multilayer laminate 23. Further, the film thickness of the fine concavo-convex layer 33 is further restricted than the film thickness of the fine concavo-convex layer 31 in the first embodiment, and is designed to have a film thickness and a structure height of the fine concavo-convex layer 33 satisfying the waveguide mode resonance condition. It is preferred that

As a method for forming the fine uneven layer 33, the method for forming the fine uneven layer 31 in the first embodiment can be applied.

Further, as a method for forming the fine uneven layer 33, the optical nanoimprint method or the thermal nanoimprint method can be more preferably used. In this case, the remaining film formed by the optical nanoimprint method or the thermal nanoimprint method can serve as the waveguide layer 42 provided in the second embodiment.

For example, when the refractive index of the material constituting the uppermost layer of the multilayer laminate 23 is about 1.4 and the refractive index of the material forming the fine uneven layer 33 is about 1.7, the structure formed in the fine uneven layer 33 The height is about 200 nm, the thickness of the fine concavo-convex layer 33 is about 300 nm, the fine concavo-convex layer 33 has a structural period of about 300 nm and about 350 nm, and the value obtained by dividing the convex dimension by the structural period is 0.5. Display bodies 3 each having a one-dimensional diffractive structure composed of a linear concavo-convex structure formed in each of the individual regions sandwiching the region where the fine structure is not formed were observed from the front. In this case, since the blue color is reflected by the guided mode resonance in the region having the structural period of about 300 nm and the green color is reflected by the guided mode resonance in the region having the structural period of about 350 nm, a structural color development different from the region where the fine structure is not formed is observed. . Further, when the display body is observed with a certain angle tilted in the arrangement direction of the linear concavo-convex structure, the reflected light due to the waveguide mode resonance cannot be observed if the display body is tilted more than a certain angle. However, since the periodic structures of the structures formed in the fine uneven layer 33 are all in the visible light wavelength region or less, structural coloration due to the multilayer laminate 23 and the fine uneven layer 33 is observed. As the value increases, a diffraction phenomenon due to the one-dimensional diffractive structure acts, and an inherent color change different from that in the structure non-formation region is observed in the structure formation region. As described above, it is possible to obtain the display body 3 that exhibits a unique color tone change in which waveguide mode resonance and the effect of the diffraction effect are imparted to the multilayer film interference.

Example 1
In Example 1, a display body in which a fine uneven layer made of SiO ₂ is formed on the surface of a multilayer laminate made of TiO ₂ and SiO ₂ by sputtering, charged particle beam exposure and dry etching will be described.

Providing a synthetic quartz glass substrate, a synthetic quartz glass substrate and a SiO ₂ of the TiO ₂ and the thickness 95nm of thickness 45nm are stacked one by four layers alternately by sputtering, and finally the TiO ₂ having a thickness of 45nm other Layers were formed to form a multilayer laminate. Further SiO ₂ having a thickness of 300nm was formed on the surface of the multilayer stack was deposited film thickness 50nm chrome (Cr) layer by sputtering SiO ₂ layer surface. Both the TiO ₂ layer and the SiO ₂ layer were formed by reactive sputtering using a metal target. The gases used for the film formation were argon (Ar) and oxygen (O ₂ ), both of which were sputtering in an oxide mode. The Cr layer was sputtered with only Ar using a metal target.

FEP171 (made by Fuji Film Electronics Materials Co., Ltd.), which is a charged particle beam exposure resist, was applied to the Cr layer surface by 200 nm, and a pattern was drawn on the resist by a variable shaped beam type electron beam. The drawn pattern is a one-dimensional diffractive structure composed of a linear concavo-convex structure having a structure period of 350 nm and a convex dimension divided by the structural period, a structure period of 700 nm, and a convex dimension of the structure period. This is a one-dimensional diffractive structure composed of a linear concavo-convex structure with a value obtained by dividing 0.5, and each drawing region is a square region having a side of 1 cm, and each pattern region is arranged without overlapping. The dose of electron beam irradiation was 10 μC / cm ^2, and post-exposure baking was performed for 10 minutes on a hot plate heated to 100 ° C. A TMAH aqueous solution was used as a developing solution, and pure water was used as a rinsing solution.

After forming a one-dimensional diffractive structure pattern consisting of a linear concavo-convex structure on the resist, an etching process using plasma using a mixed gas of chlorine and oxygen was performed, and the resist pattern was transferred to the Cr film. An ICP dry etching apparatus was applied to the etching process. After introducing 50 sccm of chlorine and 10 sccm of oxygen and setting the pressure in the plasma chamber to 1 Pa, ICP power 500 W and RIE power 50 W were applied to cause plasma discharge.

Further, an etching process using plasma using a mixed gas of hexafluoroethane and helium was performed, and the pattern formed on the Cr film was transferred to the SiO ₂ layer. An ICP dry etching apparatus was applied to the etching process. Ethane hexafluoride and helium were introduced at 50 sccm at a time, the pressure in the plasma chamber was set to 1 Pa, and then ICP power 500 W and RIE power 200 W were applied to cause plasma discharge. The etching depth of SiO ₂ was 200 nm.

Next, organic cleaning using NMP (N-methyl-2-pyrrolidone), MEA (monoethanolamine), etc., removal of residual Cr film with a mixed aqueous solution of diammonium cerium nitrate and nitric acid, and aqueous ammonia and peroxidation Alkali cleaning using a mixed solution with hydrogen water or the like was performed to obtain a display body on which a fine uneven layer made of SiO ₂ having a structure height of 200 nm and a film thickness of 300 nm was formed.

When the display was observed from the front, a green to yellow structural color was confirmed in the pattern-unformed region, and it was confirmed that the structural color was blue-shifted by tilting the display. On the other hand, when the region where the one-dimensional diffractive structure having a structure period of 700 nm was formed was observed from the front, structural color development with a strong blue color was confirmed as compared with the unformed pattern basin. Furthermore, when the display body was observed while tilting in the arrangement direction of the linear concavo-convex structure, an amber colored structure was observed, and an inherent color tone change due to the one-dimensional diffractive structure was confirmed. Further, when the region where the one-dimensional diffractive structure having a structure period of 350 nm was formed was observed from the front, the color formation was almost the same as that of the pattern-unformed region, but the display was tilted in the arrangement direction of the linear concavo-convex structure. As a result of observation, an amber colored structure was observed, and a unique color tone change due to the one-dimensional diffraction structure was confirmed.

(Example 2)
In Example 2, a display body in which the uppermost layer of a multilayer laminate made of TiO ₂ and SiO ₂ is made of SiO ₂ and a fine uneven layer made of a photocurable resin is formed by an ultraviolet nanoimprint method will be described.

First, on a synthetic quartz glass substrate, a one-dimensional diffractive structure consisting of a linear concavo-convex structure having a structure period of 350 nm, a structure height of 200 nm, and a value obtained by dividing the convex dimension by the structure period is 0.5. A pattern composed of a one-dimensional diffractive structure composed of a linear concavo-convex structure having a structure period of 400 nm, a structure height of 200 nm, and a value obtained by dividing the convex dimension by the structure period is 0.5. An ultraviolet nanoimprint mold was prepared, which was formed in a 1 cm square region and each pattern region was arranged without overlapping.

Optool (registered trademark) HD-1100Z (manufactured by Daikin Industries, Ltd.) was applied as a release agent to the mold surface for ultraviolet nanoimprint.

Next, a 4-inch synthetic quartz glass wafer was prepared, and a multilayer laminate was formed by alternately stacking TiO ₂ having a thickness of 40 nm and SiO ₂ having a thickness of 60 nm on the synthetic quartz glass wafer by sputtering. .

Subsequently, for UV nanoimprinting, a photocurable resin MUR-6 (manufactured by Maruzen Petrochemical Co., Ltd.) having a film thickness of 200 nm is applied on a synthetic quartz glass wafer on which a multilayer laminate is formed, and a release agent is applied. The mold surface was brought into contact, a pressure of 2 MPa was applied, and ultraviolet light having a wavelength of 365 nm was irradiated from the back surface of the ultraviolet nanoimprint mold to cure the photocurable resin. The treatment was performed at room temperature, and the exposure amount of ultraviolet light was 100 mJ / cm ² .

Next, the synthetic quartz glass wafer was peeled from the ultraviolet nanoimprint mold to obtain a display body on which a fine uneven layer made of a photocurable resin was formed.

When the display body was observed from the front, blue to blue-green structural color was confirmed in the pattern-unformed region, and it was confirmed that the structural color was blue-shifted by tilting the display body. On the other hand, when a region where a one-dimensional diffractive structure having a structure period of 350 nm was formed was observed from the front, a structural color development with a stronger green color was confirmed as compared with a pattern-unformed basin. Furthermore, when the display body was observed while being tilted in the arrangement direction of the linear concavo-convex structure, yellow structural coloration was observed, and a unique color tone change due to the one-dimensional diffractive structure could be confirmed. When the region where the one-dimensional diffractive structure having a structure period of 400 nm was formed was observed from the front, a structural color development with a strong yellow color was confirmed as compared with the unpatterned basin. Furthermore, when the display body was observed while being tilted in the arrangement direction of the linear concavo-convex structure, yellow structural coloration was observed, and a unique color tone change due to the one-dimensional diffractive structure could be confirmed. As described above, the inherent color change due to the one-dimensional diffractive structure was confirmed.

The display body of the present invention can be used for display objects with high design properties. In particular, it is expected to be suitably used in the field of anti-counterfeiting technology.

1, 2, 3 Display body 11, 12, 13 Base material 21, 22, 23 Multilayer laminate 31, 32, 33 Fine uneven layer 42 Waveguide layer

Claims (13)

1. In a display including a substrate, a multilayer laminate formed on the surface of the substrate, and a fine uneven layer formed on the surface of the multilayer laminate,
   The multilayer laminate is a laminate of two or more layers,
   For light of a predetermined wavelength region, at least the multilayer laminate and the fine uneven layer have transparency,
   Each layer constituting the multilayer laminate is made of a material having a refractive index different from that of an adjacent layer with respect to light having a wavelength in the predetermined wavelength region,
   Each layer constituting the multilayer laminate and the material constituting the fine concavo-convex layer has an optical film thickness represented by the product of the refractive index and the physical film thickness, which is 7 / of the shortest wavelength in the predetermined wavelength region. Less than 4 times,
   In the fine concavo-convex layer, a concavo-convex structure including a convex part and a concave part having a height difference equal to or less than the physical film thickness is formed by partially reducing the physical film thickness of the fine concavo-convex layer. .
2. 2. The display according to claim 1, wherein a one-dimensional diffractive structure composed of a linear concavo-convex structure with a constant period or a two-dimensional diffractive structure composed of a lattice-shaped concavo-convex structure with a constant period is formed on the surface of the fine concavo-convex layer. body.
3. The refractive index with respect to the light of the wavelength in the said wavelength range of the material which comprises the said fine uneven | corrugated layer is larger than the refractive index with respect to the light of the said wavelength of the material which comprises the uppermost layer of the said multilayer laminated body. Display body described in 1.
4. Between the uppermost layer of the multilayer laminate and the fine concavo-convex layer, a material having a refractive index larger than that of the material constituting the fine concavo-convex layer, with respect to light having a wavelength in the wavelength region, and having a physical film thickness and a refractive A waveguide layer having an optical film thickness that is a product of the refractive index and less than 7/4 times the shortest wavelength in the wavelength region;
   The display body according to claim 1, wherein a difference in height between the convex and concave portions of the concavo-convex structure of the fine concavo-convex layer is equal to a physical film thickness of the fine concavo-convex layer.
5. The wavelength region is a visible light wavelength region;
   A plurality of pixel regions arranged on a matrix having at least one side of 10 μm or more are formed on the surface of the fine uneven layer,
   Each pixel area
   A first one-dimensional diffractive structure comprising a linear concavo-convex structure having a structure period of 200 nm or more and 800 nm or less, wherein the linear concavo-convex structure is arranged in a first direction;
   A second one-dimensional diffractive structure comprising a linear concavo-convex structure having a structure period of 200 nm or more and 800 nm or less, wherein the linear concavo-convex structure is arranged in a second direction different from the first direction;
   It has a lattice-like uneven structure with a structure period of 200 nm or more and 800 nm or less, and the lattice-like uneven structure is arranged in the first direction and the second direction to form at least one of a two-dimensional diffraction structure. The display body according to any one of claims 1 to 4.
6. The said base material, each said multilayer laminated body layer, and the said fine uneven | corrugated layer are comprised with the material whose extinction coefficient is 0.1 or less with respect to the light of visible light wavelength range. The display body.
7. A material in which the base material, each layer of the multilayer laminate, the fine uneven layer, and the waveguide layer have a refractive index of 1.3 or more and 2.6 or less with respect to light having a wavelength in a visible light wavelength region. The display body according to claim 4, wherein the refractive index difference between adjacent layers is at least 0.05 or more.
8. A step of forming a multilayer laminate having transparency to light in a visible light wavelength region on the surface of the base material and having a different refractive index in each adjacent layer by sequentially laminating the layers;
   Applying a photocurable resin to the surface of the multilayer laminate;
   And a step of forming a desired concavo-convex shape on the photocurable resin by an optical nanoimprint method.
9. The display body according to claim 8, wherein a refractive index of the photocurable resin with respect to light having a wavelength in a visible light wavelength region is larger than a refractive index with respect to a visible light wavelength region of a material constituting the surface of the multilayer laminate. Method.
10. Preparing a substrate;
    A step of forming a laminated body having transparency to light having a wavelength in a visible light region on the surface of the base material and having different refractive indexes in adjacent layers by sequentially laminating the layers;
    Forming a waveguide layer on the surface of the multilayer laminate;
    A step of applying a photocurable resin having a refractive index smaller than that of a material constituting the waveguide layer on the surface of the waveguide layer with respect to light having a wavelength in the visible light region;
    A method for producing a display body, comprising: a step of forming a desired concavo-convex shape on the photocurable resin by a photo nanoimprint method; and a step of removing a residual film by plasma exposure.
11. Preparing a substrate;
    A step of forming a laminated body having transparency to light having a wavelength in a visible light region on the surface of the base material and having different refractive indexes in adjacent layers by sequentially laminating the layers;
    Applying a thermoplastic resin layer to the top surface of the multilayer laminate;
    Forming a desired concavo-convex shape on the thermoplastic resin layer by a thermal nanoimprint method.
12. 12. The display body according to claim 11, wherein a refractive index of the thermoplastic resin layer with respect to light having a wavelength in a visible light region is larger than a refractive index with respect to light having the wavelength of a material constituting the outermost surface of the multilayer laminate. Method.
13. Preparing a substrate;
    A step of forming a laminate having transparency to light having a wavelength in a visible light wavelength region on the surface of the base material and having a different refractive index in each adjacent layer by sequentially stacking the layers;
    Forming a waveguide layer on the surface of the multilayer laminate;
    Applying a thermoplastic resin layer having a smaller refractive index to light having a wavelength in the visible wavelength region than the material constituting the waveguide layer on the surface of the waveguide layer;
    A method for producing a display body, comprising: a step of forming a desired uneven shape on the thermoplastic resin layer by a thermal nanoimprint method; and a step of removing a remaining film by plasma exposure.

Images