JP7225612B2 - Display body - Google Patents

Description

The present invention relates to a display and a method of manufacturing the display.

The display adds a visual effect different from printed matter to an image displayed by the display by utilizing light interference by a diffraction grating or a multilayer film (see, for example, Patent Document 1). For example, the display body is provided on an article that is required to be difficult to forge, such as authentication documents such as passports and driver's licenses, and securities such as gift certificates and checks. enhance sexuality. In addition, the display body enhances the design of the article by being provided on the article around us.

Japanese Patent No. 5124272

In order to further enhance designability, it is preferable that one display body can form images with different appearances depending on viewing conditions. For example, a display body in which images of different colors are visually recognized when observing the front surface and the rear surface of the display body, or different colors are observed when observing reflected light and observing transmitted light on one surface of the display body. There is a demand for a display on which the image of is visually recognized.

In addition, in order to increase the difficulty of counterfeiting, there is a demand for a display body having a watermark effect, in which patterns and characters that cannot be seen by observing reflected light are visible by observing light transmitted through one surface of the display body.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display body that allows images with different appearances to be visually recognized according to observation conditions, and that is excellent in design and security due to the watermark effect, and a method for manufacturing the display body. do.

A display body that solves the above problems is a supporting portion having a reference plane, and a plurality of periodic elements arranged in a two-dimensional lattice pattern having a sub-wavelength period on the reference plane, the projections protruding from the reference plane, or A surface of the periodic structure, which is a surface including a region surrounding the periodic element and the surface of the periodic element on the reference surface and a metal layer having a shape that follows the surface shape of the periodic structure,
on the reference plane,
a first lattice layer having a thickness of 10 nm or more and 200 nm or less;
a second lattice layer provided above the first lattice layer and having a thickness of 10 nm or more and 200 nm or less;
an intermediate lattice layer thicker than the first lattice layer and the second lattice layer, the intermediate lattice layer sandwiched between the first lattice layer and the second lattice layer in the thickness direction;
A light shielding layer is provided between the reference surface of the support and the first grating layer, or on the surface of the support on the opposite side to the reference surface,
The first lattice layer includes a plurality of first dielectric layers periodically arranged in an island-like array, and a mesh-like first metal layer surrounding each first dielectric layer,
The intermediate lattice layer has a plurality of first intermediate dielectric layers arranged periodically in an island-like arrangement and a mesh shape surrounding each first intermediate dielectric layer, and has a lower dielectric value than the first intermediate dielectric layer. a second intermediate dielectric layer having a coefficient of
The second lattice layer includes a plurality of second metal layers periodically arranged in an island-like arrangement, and a mesh-like second dielectric layer surrounding each second metal layer,
The periodic element is a protrusion, the first dielectric layer and the first intermediate dielectric layer constitute the periodic element, and the metal layer includes the first metal layer and the second metal layer.

In the above configuration, the volume ratio of the first metal layer in the first lattice layer is larger than the volume ratio of the second metal layer in the second lattice layer, and the second metal layer in the second lattice layer the volume ratio of the layer is greater than the volume ratio of the metal material in the intermediate lattice layer,
A ratio of the width of the first dielectric layer to the structure period of the first dielectric layer and a ratio of the width of the second metal layer to the structure period of the second metal layer are 0.25 or more and 0.75. and
The first metal layer and the second metal layer may be made of a material having a negative real part of the complex dielectric constant for light in the visible region.

In the above structure, the light shielding layer may be made of a material that absorbs visible light wavelengths.

In the above configuration, the light shielding layer may be made of a metal material having a negative real part of a complex permittivity with respect to light in the visible region.

In the above structure, the ratio of the width of the first dielectric layer to the structure period of the first dielectric layer and the ratio of the width of the second metal layer to the structure period of the second metal layer are 0.40 or more and 0.60. It may be below.

In the above structure, the first dielectric layer and the first intermediate dielectric layer are an integrated structure, the thickness of the first lattice layer is 100 nm or less, and the thickness of the second lattice layer is 100 nm or less. and the thickness of the intermediate lattice layer may be 150 nm or less.

In the above configuration, the first lattice layer does not have to have a boundary with the support portion, and when the first lattice layer and the support portion are integrated, the total of the first lattice layer and the support portion may be 50 nm or more and 500 nm or less.

In the above structure, the light shielding layer is made of the same material as the first metal layer and the second metal layer, the second dielectric layer is an air layer, and the refractive index of the first dielectric layer and the The difference between the refractive indices may be greater than the difference between the refractive indices of the second dielectric layer and the second metal layer.

In the above structure, the first dielectric layer and the first intermediate dielectric layer may be an integrated structure, and the second intermediate dielectric layer and the second dielectric layer may be an integrated structure.

According to the above configuration, the first dielectric layer and the first intermediate dielectric layer are an integrated structure, and the second intermediate dielectric layer and the second dielectric layer are an integrated structure. , it also becomes possible to simplify the structure of the display.

In the above configuration, a dielectric layer may be provided on the surface of the metal layer opposite to the surface in contact with the periodic structure and having a shape following the surface shape of the metal layer.

A manufacturing method for solving the above problems includes a first step of forming a light shielding layer on a reference surface of a support portion having a reference surface or on a surface of the support portion opposite to the reference surface; A periodic structure in which periodic elements, which are projections when viewed from the direction facing the reference plane, are positioned in a two-dimensional lattice pattern with a sub-wavelength period are formed by resin on the surface of the supporting portion on the reference plane side. a second step; and a third step of forming a metal layer having a shape following the surface shape of the periodic structure on the periodic structure.

According to the manufacturing method described above, it is possible to obtain a display on which images having different appearances can be visually recognized according to observation conditions. In particular, a periodic structure having fine unevenness can be easily and favorably formed.

The manufacturing method may include a fourth step of forming a dielectric layer covering the metal layer.

According to the above manufacturing method, by changing the material constituting the dielectric layer, it is possible to adjust the color observed by reflection observation or transmission observation of the display body, so the degree of freedom in adjusting such color is increased. be done.

Advantageous Effects of Invention According to the present invention, it is possible to provide a display body that allows images with different overviews to be visually recognized according to observation conditions, and that is excellent in design and security.

The top view which shows the planar structure in 1st Embodiment of a display body. FIG. 4 is an enlarged view showing an enlarged planar structure of a first display area in the display body of the first embodiment; FIG. 3 is a diagram showing the cross-sectional structure of the first display area of the first embodiment, and is a cross-sectional view taken along the line III-III of FIG. 2; FIG. 3 is a diagram showing the cross-sectional structure of the first display area of the first embodiment, and is a cross-sectional view taken along line IV-IV of FIG. 2; FIG. 2 is a view showing the cross-sectional structure of the second display area of the first embodiment, and is a cross-sectional view taken along the line VV of FIG. 1; FIG. 4 is an operation diagram showing the operation of the display member of the first embodiment by reflection observation on the front surface side and transmission observation on the back surface side; FIG. 4 is an operation diagram showing the operation of the display member of the first embodiment by reflection observation on the back surface side and transmission observation on the front surface side; Sectional drawing which expands and shows a part of cross-sectional structure in the 1st display area of the modification of 1st Embodiment. FIG. 3 is a diagram showing the cross-sectional structure of the first display region of the second embodiment, and is a cross-sectional view taken along the line III-III of FIG. 2; FIG. 3 is a diagram showing the cross-sectional structure of the first display area of the second embodiment, and is a cross-sectional view taken along line IV-IV of FIG. 2; FIG. 2 is a view showing a cross-sectional structure of a second display area of the second embodiment, and is a cross-sectional view taken along the line VV of FIG. 1; FIG. 10 is a functional diagram showing the function of the display of the second embodiment by reflection observation on the front side and transmission observation on the back side; FIG. 11 is a functional diagram showing the function of the display member of the second embodiment by reflection observation on the back surface side and transmission observation on the front surface side; Sectional drawing which expands and shows a part of cross-sectional structure in the 1st display area of the modification of 2nd Embodiment. Sectional drawing which expands and shows a part of cross-sectional structure in the 1st display area of the modification of 2nd Embodiment.

(First embodiment)
A first embodiment of a display and a method for manufacturing the display will be described with reference to FIGS. 1 to 7. FIG. The indicator 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 both of these purposes. For the purpose of increasing the difficulty of counterfeiting goods, the label is attached to authentication documents such as passports and driver's licenses, securities such as gift certificates and checks, cards such as credit cards and cash cards, banknotes, etc. Attached. In addition, for the purpose of improving the design of the article, the display body may be, for example, an ornament worn on the body, an article carried by the user, an article to be placed such as furniture or home appliances, or a structure such as a wall or a door. It can be attached to things.

As shown in FIG. 1, the surface 10S of the display is divided into a first display area 10A and a second display area 10B. The cross-sectional structure of the first display region 10A and the cross-sectional structure of the second display region 10B are different from each other. The first display area 10A is an area where characters, figures, symbols, patterns, pictures, etc. are drawn on the surface 10S. In FIG. 1, for example, it is an area where a star-shaped figure is drawn.

[Structure of Display]
First, the configuration of the first display area 10A will be described below.

As shown in FIG. 2, the first display area 10A includes a plurality of isolated areas A2 and a single peripheral area A3 surrounding each isolated area A2 when viewed from the direction facing the surface 10S of the display. In FIG. 2, each isolated area A2 is indicated by a dot for convenience of explanation of the isolated area A2.

Each isolated area A2 is arranged in a square array along the surface 10S. A square array is an array in which an isolated region A2 is located at each vertex of a square LT having one side with the structural period PT. The isolated areas A2 can also be arranged in a hexagonal array in which the isolated areas A2 are located at the vertices of an equilateral triangle. That is, the isolated regions A2 are periodically arranged in an island-like arrangement.

As shown in FIG. 3, the display includes a transparent support 11a that transmits light in the visible region. Light in the visible region has a wavelength of 400 nm or more and 800 nm or less. The support portion 11a is common to the first display area 10A and the second display area 10B. The cross-sectional structure of the support portion 11a may be a single-layer structure or a multi-layer structure.

The material forming the support portion 11a is a dielectric, such as a resin such as a photocurable resin, or an inorganic material such as quartz. From the viewpoints of flexibility required for attaching a display member to an article and a high degree of freedom in optical characteristics that can be added to the support portion 11a, resin is used as the material for the support portion 11a. Preferably. The refractive index of the supporting portion 11a is higher than that of the air layer, and is, for example, 1.2 or more and 1.7 or less.

The first display region 10A includes a light shielding layer 10, an intermediate layer 11b, a first grating layer 21, an intermediate grating layer 31, and a second grating layer 41 in order from the layer closest to the supporting portion 11a. The intermediate lattice layer 31 is sandwiched between the first lattice layer 21 and the second lattice layer 41 . The surface of the support portion 11a on which the light shielding layer 10 is positioned is the surface of the support portion 11a, and the side of the support portion 11a on which the light shielding layer 10 is positioned is the surface side of the display body. On the contrary, the side where the support portion 11a is positioned with respect to the light shielding layer 10 is the back side of the display body.

[Light shielding layer 10]
A light shielding layer 10 is positioned on the surface of the supporting portion 11a. The material forming the light shielding layer 10 may be a material that absorbs the visible wavelength band, or may be a metal. From the standpoint that the watermark effect is likely to occur, the thickness of the light shielding layer 11a is preferably 5 nm or more and 50 nm or less, and the transmittance is preferably 10% or more and 20% or less.

[Intermediate layer 11b]
An intermediate layer 11b is positioned on the light shielding layer 10 . Intermediate layer 11 b may not have a boundary with each first dielectric layer 22 . FIG. 3 shows a structure in which the layer on the surface side of the intermediate layer 11b is integrated with each first dielectric layer 22. FIG. In the structure in which the intermediate layer 11b and each first dielectric layer 22 are integrated, the total thickness of the intermediate layer 11b and each first dielectric layer 22 is preferably 50 nm or more and 500 nm or less.

[First grating layer 21]
A first grating layer 21 is located on the intermediate layer 11b. The first grating layer 21 comprises a plurality of first dielectric layers 22 and a single first metal layer 23 . Each first dielectric layer 22 is located in the isolated area A2 when viewed from the direction facing the surface 10S of the display. The single first metal layer 23 is located in the peripheral area A3 when viewed from the direction facing the surface 10S. The plurality of first dielectric layers 22 are periodically arranged in an island-like arrangement along the surface 10S.

Each first dielectric layer 22 is a structure protruding from the surface of the support portion 11b. Each first dielectric layer 22 protrudes from the intermediate layer 11b, and each first dielectric layer 22 and the intermediate layer 11b are integral.

The first metal layer 23 has a mesh shape surrounding each first dielectric layer 22 when viewed from the direction facing the surface 10S. In the first lattice layer 21, a single first metal layer 23 is an optical sea component over which free electrons are distributed, and each first dielectric layer 22 is an island component distributed within the sea component. .

When viewed from the direction facing the surface 10S, the period in which the first dielectric layers 22 are positioned is the sum of the shortest width WP of the adjacent first dielectric layers 22 and the width WT of the first dielectric layers 22. which is the structural period PT. The structural period PT is a sub-wavelength period below the wavelength in the visible region.

A ratio of the width WT of the first dielectric layer 22 to the structural period PT is 0.25 or more and 0.75 or less. From the standpoints of obtaining high processing accuracy of the first lattice layer 21 and facilitating plasmon resonance in the first lattice layer 21, the ratio of the width WT of the first dielectric layer 22 to the structural period PT is preferably , from 0.40 to 0.60.

The thickness of the first lattice layer 21 is preferably 10 nm or more and 200 nm or less. From the viewpoints of obtaining high processing accuracy of the first grating layer 21, easy occurrence of plasmon resonance in the first grating layer 21, and clear colors of images obtained by each observation, the thickness of the first grating layer 21 is The thickness is preferably 10 nm or more and 100 nm or less.

[Intermediate grating layer 31]
An intermediate lattice layer 31 is located on the first lattice layer 21 . The thickness of the intermediate grating layer 31 is thicker than the thickness of the first grating layer 21 . From the viewpoint of obtaining high processing accuracy of the intermediate lattice layer 31, the thickness of the intermediate lattice layer 31 is preferably 150 nm or less.

Intermediate lattice layer 31 comprises a plurality of first intermediate dielectric layers 32 and a single second intermediate dielectric layer 33 . Each first intermediate dielectric layer 32 is located in the isolated area A2 when viewed from the direction facing the surface 10S. A single second intermediate dielectric layer 33 is located in the peripheral region A3, viewed from the direction facing the surface 10S. The plurality of first intermediate dielectric layers 32 are periodically arranged in an island-like array along the surface 10S.

Each first intermediate dielectric layer 32 is a structure protruding from the first dielectric layer 22 . Each first intermediate dielectric layer 32 is, for example, integral with the first dielectric layer 22 . Alternatively, each first intermediate dielectric layer 32 is separate from the first dielectric layer 22, eg, with a boundary therebetween. When viewed from the direction facing the surface 10S, the period at which the first intermediate dielectric layer 32 is positioned is the same as the first dielectric layer 22, the sum of the shortest width WP and the width WT, which is the structural period PT. . A ratio of the width WT of the first intermediate dielectric layer 32 to the structural period PT is 0.25 or more and 0.75 or less. Also, the ratio of the width WT of the first intermediate dielectric layer 32 to the structural period PT is preferably 0.40 or more and 0.60 or less.

The second intermediate dielectric layer 33 has a mesh shape surrounding each first intermediate dielectric layer 32 when viewed from the direction facing the surface 10S. In the intermediate grating layer 31, a single second intermediate dielectric layer 33 is structurally and optically a sea component and each first intermediate dielectric layer 32 is structurally and optically an island component. The second intermediate dielectric layer 33 is an air layer or a resin layer and has a dielectric constant lower than that of the first intermediate dielectric layer 32 .

[Second grating layer 41]
A second lattice layer 41 is located on the intermediate lattice layer 31 . The thickness of the second lattice layer 41 is preferably 10 nm or more and 200 nm or less, and the thickness of the second lattice layer 41 is thinner than the thickness of the intermediate lattice layer 31 . The thickness of the second grating layer 41 is high from the viewpoints of obtaining high processing accuracy of the second grating layer 41, easiness of occurrence of plasmon resonance in the second grating layer 41, and clearness of colors of images obtained by each observation. The thickness is preferably 10 nm or more and 100 nm or less.

The second grating layer 41 comprises a plurality of second metal layers 42 and a single second dielectric layer 43 . Each second metal layer 42 is located in the isolated area A2 when viewed from the direction facing the surface 10S. A single second dielectric layer 43 is located in the peripheral region A3 when viewed from the direction facing the surface 10S. The plurality of second metal layers 42 are periodically arranged in an island-like arrangement along the surface 10S.

Each second metal layer 42 is a structure overlying the top surface of the first interlevel dielectric layer 32 . Each second metal layer 42 has a boundary with and is separate from the first interlevel dielectric layer 32 . When viewed from the direction facing the surface 10S, the period at which the second metal layers 42 are positioned is the sum of the shortest width WP and the width WT, which is the structural period PT, as in the case of the first dielectric layer 22 . The ratio of the width of the second metal layer 42 to the structural period PT is 0.25 or more and 0.75 or less. Also, the ratio of the width of the second metal layer 42 to the structural period PT is preferably 0.40 or more and 0.60 or less.

The second dielectric layer 43 has a mesh shape surrounding each second metal layer 42 when viewed from the direction facing the surface 10S. In the second grating layer 41, the single second dielectric layer 43 is an optical sea component with fewer free electrons than the second metal layers 42, and each second metal layer 42 is in the sea component. is an island component distributed in The second dielectric layer 43 is an air layer or a resin layer and has a dielectric constant lower than that of the first intermediate dielectric layer 32 .

The volume ratio of the first metal layer 23 as the sea component in the first lattice layer 21 is greater than the volume ratio of the second metal layer 42 as the island component in the second lattice layer 41 . Also, the volume ratio of the second metal layer 42 , which is an island component, in the second lattice layer 41 is greater than the volume ratio of the metal material in the intermediate lattice layer 31 .

As shown in FIG. 4, in the peripheral region A3, the light shielding layer 10, the intermediate layer 11b, the first grating layer 21, the intermediate grating layer 31, and the second grating layer 41 are arranged in this order from the layer closest to the supporting portion 11a. and are located.

Next, the configuration of the second display area 10B will be described below.

As shown in FIG. 5, the second display region 10B does not include the intermediate layer 11b, the first grating layer 21, the intermediate grating layer 31, and the second grating layer 41 on the supporting portion 11a. . That is, the second display region 10B transmits light in the visible region according to the light transmittance provided by the supporting portion 11a and the light shielding layer 10. FIG.

In addition, the second display region 10B may have a layer different from that of the first display region 10A on the supporting portion 11a. The second display area 10B may include only the light shielding layer 10, for example. Also, the second display region 10B may include a layer made of the same material as the light shielding layer 10 and the first metal layer 23, for example. The layer structure in the second display area 10B is appropriately selected according to the requirements for the image displayed by the second display area 10B.

[Material of each lattice layer]
The first dielectric layer 22 and the first intermediate dielectric layer 32 are dielectrics, and are made of, for example, a resin such as a photocurable resin or an inorganic material such as quartz. The refractive index of each of the first dielectric layer 22 and the first intermediate dielectric layer 32 is higher than that of the air layer, and is, for example, 1.2 or more and 1.7 or less.

The material forming the first metal layer 23 and the second metal layer 42 is preferably a material having a negative real part of the complex dielectric constant at wavelengths in the visible region, such as aluminum, silver, gold, indium, Tantalum or the like is preferred. The first metal layer 23 and the second metal layer 42 are made of, for example, the same material.

The light shielding layer 10 is preferably made of a material that absorbs the visible wavelength band, such as a carbon-based black pigment or a titanium-based black pigment. Further, the light shielding layer 10 is preferably made of a material having a complex dielectric constant with a negative real part at wavelengths in the visible region, such as aluminum, silver, gold, indium, and tantalum.

[Optical Configuration and Action of Display]
Next, the optical configuration and action of the display will be described.

Here, the front surface 10S of the display body and the rear surface 10T of the display body are in contact with air layers, respectively, and the second intermediate dielectric layer 33 and the second dielectric layer 43 are each an air layer, or , a resin layer having a refractive index close to that of an air layer will be described as an example.

As shown in FIG. 6, the refractive index of the supporting portion 11a is determined by the dielectric and is greater than the refractive index of the air layer.

When the layer on the surface side of the intermediate layer 11b is integrated with each first dielectric layer 22, the refractive index of the intermediate layer 11b is equal to that of the first dielectric layer 22 and higher than that of the air layer.

The refractive index of the first dielectric layer 22 is higher than that of the air layer, and the refractive index of the first metal layer 23 is lower than that of the air layer. The refractive index of the first lattice layer 21 is approximated to the averaged size by the refractive index of the first metal layer 23 and the refractive index of the first dielectric layer 22 . Since the ratio of the width WT of the first dielectric layer 22 to the structural period PT is 0.25 or more and 0.75 or less, the refractive index of the first lattice layer 21 is, after all, the sea component of the first metal The size is governed by the layer 23 and is sufficiently lower than the refractive index of the air layer.

The refractive index of the first intermediate dielectric layer 32 is higher than the refractive index of the air layer, and the refractive index of the second intermediate dielectric layer 33 is equal to or higher than the refractive index of the air layer. expensive. The refractive index of the intermediate grating layer 31 is approximated to the averaged size by the refractive index of the second intermediate dielectric layer 33 and the refractive index of the first intermediate dielectric layer 32 . Since the ratio of the width WT of the first intermediate dielectric layer 32 to the structural period PT is 0.25 or more and 0.75 or less, the refractive index of the intermediate grating layer 31 is, after all, the second intermediate dielectric layer 32 which is the sea component. The size is governed by the dielectric layer 33, and is higher than and close to the refractive index of the air layer.

The refractive index of the second metal layer 42 is lower than the refractive index of the air layer, and the refractive index of the second dielectric layer 43 is equal to or higher than the refractive index of the air layer. The refractive index of the second lattice layer 41 is approximated to the averaged size by the refractive index of the second dielectric layer 43 and the refractive index of the second metal layer 42 . Since the ratio of the width WT of the second metal layer 42 to the structural period PT is 0.25 or more and 0.75 or less, the refractive index of the second lattice layer 41 is, after all, the sea component of the second dielectric The size is governed by the layer 43, which is lower than the refractive index of the air layer and close to the air layer.

[Front reflection observation, back transmission observation]
Here, the white light L1 incident on the second grating layer 41 from the outside of the display enters the second grating layer 41 through the air layer, and enters the intermediate grating layer 31 through the second grating layer 41 . The light L1 incident on the second grating layer 41 enters the second grating layer 41 having a refractive index close to that of the air layer through the air layer. Hard to come by. Further, the light incident on the intermediate grating layer 31 enters the intermediate grating layer 31 having a refractive index close to that of the air layer through the second grating layer 41 having a refractive index close to that of the air layer. Fresnel reflection is less likely to occur at the interface between the grating layer 41 and the intermediate grating layer 31 .

On the other hand, since the structural period PT of the second metal layer 42 is a sub-wavelength period equal to or shorter than the wavelength in the visible region, plasmon resonance occurs in the second lattice layer 41 . Plasmon resonance is a phenomenon in which part of the light incident on the second lattice layer 41 is coupled with collective vibration of electrons. Part of the light L<b>1 incident on the second grating layer 41 is converted into surface plasmons by plasmon resonance in the second grating layer 41 , and the surface plasmons pass through the second grating layer 41 . The surface plasmons transmitted through the second grating layer 41 are reconverted into light and emitted. The wavelength region of the light EP2 emitted by the second grating layer 41 due to plasmon resonance is a specific wavelength region depending on the grating structure including the structural period PT of the second metal layer 42 and the material. As a result, the second grating layer 41 transmits part of the wavelength region of the light incident on the second grating layer 41 to the intermediate grating layer 31 .

Further, since the structural period PT of the first dielectric layer 22 is also a sub-wavelength period equal to or shorter than the wavelength in the visible region, plasmon resonance also occurs in the first grating layer 21 . That is, part of the light incident on the first grating layer 21 is also converted into surface plasmons by plasmon resonance in the first grating layer 21, and the surface plasmons pass through the first grating layer 21 and are reconverted into light. emitted by The wavelength region of the light EP1 emitted by the first grating layer 21 due to plasmon resonance is a specific wavelength region depending on the grating structure including the structural period PT of the first dielectric layer 22 and the material. As a result, the first grating layer 21 transmits part of the wavelength region of the light incident on the first grating layer 21 to the intermediate layer 11b.

Further, part of the light incident on the intermediate layer 11b is reflected or transmitted by the light shielding layer 10. FIG. The light EP1 emitted as light caused by plasmon resonance again causes plasmon resonance with the light shielding layer 10, and only the light caused by resonance is reflected or transmitted.

As described above, according to the surface reflection observation in which the light L1 is incident on the second grating layer 41 from the outside of the display body and the surface 10S is observed from the surface side of the display body, Fresnel reflection hardly occurs at each interface. , causing plasmon resonance in each of the grating layers, and these together, black or a color close to black is visually recognized in the first display area 10A.

On the other hand, according to the rear transmission observation in which the light L1 is incident on the second grating layer 41 from the outside of the display body and the rear face 10T is observed from the rear face side of the display body, the light is transmitted through the plasmon resonance in each grating layer. The colored light LP1 is partially reflected or transmitted by plasmon resonance with the light shielding layer 10, and is visually recognized in the first display area 10A.

As a result, in rear transmission observation, part of the colored light transmitted through the plasmon resonance in the light shielding layer 10 and the grating layers is blocked, and a watermark effect can be obtained. The results of the front surface reflection observation and the back surface transmission observation show the same tendency even when the amount of external light toward the front surface 10S is higher than the amount of external light toward the back surface 10T.

[Back reflection observation, front transmission observation]
As shown in FIG. 7, the white light L1 incident on the supporting portion 11a from the outside of the display enters the supporting portion 11a through the air layer and enters the light shielding layer 10 from the supporting portion 11a. The light L1 incident on the light shielding layer 10 having a higher refractive index than the air layer is reflected at the interface between the supporting portion 11a and the light shielding layer 10 . As described above, in the rear surface reflection observation, the light reflected by the light shielding layer 10 is visually recognized in the first display area 10A.

On the other hand, in the surface transmission observation in which the light L1 is incident on the support portion 11 from the outside of the display and the surface 10S is observed from the surface side of the display, the colored light passes through the plasmon resonance in the light shielding layer 10 and each lattice layer. LP2 is visually recognized in the first display area 10A. The results of the front surface transmission observation and the back surface reflection observation show the same tendency even when the amount of external light directed to the back surface 10T is higher than the amount of external light directed to the front surface 10S.

[Manufacturing method of display]
Next, an example of a method of manufacturing a display will be described.

First, the light shielding layer 10 is formed on the surface of the supporting portion 11a. The forming method is, for example, a vacuum deposition method or a sputtering method.

Subsequently, an intermediate layer 11b, a first dielectric layer 22, and a first intermediate dielectric layer 32 are formed on the surface of the light shielding layer 10. Next, as shown in FIG. The first dielectric layer 22 and the first intermediate dielectric layer 32 are integrally formed as protrusions protruding from the surface of the intermediate layer 11b. The method of forming the projections is, for example, photolithography using light or charged particle beam, nanoimprinting, and plasma etching.

For example, as shown in FIG. 3, when manufacturing a display having an uneven structure composed of the intermediate layer 11b, the first dielectric layer 22, and the first intermediate dielectric layer 32, first, as the base material 11a, A polyethylene terephthalate sheet is used to form the light shielding layer 10 on the surface of the substrate 11a. Next, the surface of the light shielding layer 10 is coated with an ultraviolet curable resin. Subsequently, the surface of the synthetic quartz mold, which is an intaglio, is pressed against the surface of the coating film made of the ultraviolet curable resin, and these are irradiated with ultraviolet rays. Furthermore, the synthetic quartz mold is released from the cured ultraviolet curable resin. As a result, the unevenness of the intaglio is transferred to the resin on the surface of the light shielding layer 10, and the intermediate layer 11b and the projections composed of the first dielectric layer 22 and the first intermediate dielectric layer 32 are formed. Note that the ultraviolet curable resin can be changed to a thermosetting resin, and the irradiation of ultraviolet rays can be changed to heating. Also, the ultraviolet curable resin can be changed to a thermoplastic resin, and the ultraviolet irradiation can be changed to heating and cooling.

Next, a first metal layer 23 and a second metal layer 42 are formed on the surfaces of the intermediate layer 11b having protrusions and the first intermediate dielectric layer 32 . Methods for forming the first metal layer 23 and the second metal layer 42 are, for example, a vacuum deposition method and a sputtering method. Thereby, a first lattice layer 21 defined by the top surface of the first metal layer 23 is formed, a second lattice layer 41 defined by the top surface of the second metal layer 42 is formed, and these first lattice layers are formed. An intermediate lattice layer 31 sandwiched between 21 and the second lattice layer 41 is formed.

As described above, according to the first embodiment, the following effects can be obtained.

(1) Since images having different colors can be visually recognized in the first display area 10A in front surface reflection observation and back surface reflection observation, it is possible to distinguish between the front and back of the display. In addition, it becomes possible to easily determine the authenticity of an article to which the display member is attached, and to enhance the design of the article to which the display member is attached.

(2) Images having different colors can be visually recognized in the first display area 10A even in front surface reflection observation and rear surface transmission observation, so that it is possible to improve the accuracy of the front/back judgment result. In addition, since images having different colors can be visually recognized in the first display area 10A in the rear surface reflection observation and the front surface transmission observation, it is possible to improve the accuracy of the determination result of the front and back surfaces.

(3) The size of the structure period PT is a sub-wavelength period equal to or less than the wavelength in the visible region, and is a size that suppresses the formation of first-order diffracted light in the visible region. Therefore, it is possible to suppress the inclusion of iridescence in the images obtained by the back surface reflection observation, the front surface transmission observation, and the rear surface transmission observation, and to make the colors of the images obtained by each observation clearer.

(4) The light-shielding layer 10 also makes it possible to impart a watermark effect in rear-surface transmission observation.

(5) Since the first dielectric layer 22 and the first intermediate dielectric layer 32 are integrated structures, and the second intermediate dielectric layer 33 and the second dielectric layer 43 are integrated, the display It also makes it possible to simplify the structure of the body. Furthermore, if the second intermediate dielectric layer 33 and the second dielectric layer 43 are configured as an integral air layer, the structure of the display can be further simplified.

(6) The color of the first display area 10A can be unique in each of front reflection observation, rear reflection observation, and transmission observation on the front or rear surface. Therefore, it is also possible to improve the accuracy in determining the authenticity of an article to which the indicator is attached.

<Modified Example of First Embodiment>
The above-described first embodiment can also be implemented with the following modifications.
[Intermediate grating layer 31]
• The first intermediate dielectric layer 32 and the second intermediate dielectric layer 33 can be embodied in separate structures. At this time, the second intermediate dielectric layer 33 is preferably a resin layer having a refractive index closer to the refractive index of the air layer than the refractive index of the first intermediate dielectric layer 32 .

• The second intermediate dielectric layer 33 and the second dielectric layer 43 can be embodied in separate structures. At this time, the second intermediate dielectric layer 33 is preferably a resin layer having a refractive index closer to the refractive index of the air layer than the refractive index of the second dielectric layer 43 .

[Protective layer]
- The display may further include a protective layer on the second metal layer 42 . At this time, the intensity of Fresnel reflection at the interface between the protective layer and the second metal layer 42 and the associated wavelength selectivity on the display vary depending on the refractive index of the protective layer. Therefore, the material constituting the protective layer is appropriately selected based on the wavelength range to be selected for the display.

It should be noted that, as shown in FIG. 8, the protective layer 45 can be embodied in a structure integral with the second dielectric layer 43 and the second intermediate dielectric layer 33 . At this time, the protective layer 45 is preferably a resin layer with a low refractive index. The low-refractive-index resin layer has a refractive index closer to the refractive index of the air layer than the refractive index of the intermediate layer 11 b, the refractive index of the first dielectric layer 22 , or the refractive index of the first intermediate dielectric layer 32 .

[Other forms]
The arrangement of the isolated regions A2 viewed from the direction facing the surface 10S of the display body is not limited to the square arrangement and the hexagonal arrangement, and may be any arrangement having periodicity. That is, the plurality of first dielectric layers 22 may be arranged periodically, the plurality of first intermediate dielectric layers 32 may also be arranged periodically, and the plurality of second metal layers 42 may be arranged periodically. should be cyclically arranged. In other words, the periodic elements of the periodic structure may be arranged with a sub-wavelength period. When the periodic elements of the periodic structure are arranged in a two-dimensional lattice, the ratio of the width WT to the structural period PT is the ratio of the width WT to the structural period PT in one direction, and the ratio is within a predetermined range. "Within" indicates that the ratio of the width WT to the structural period PT is within a predetermined range for each of the two directions in which the periodic elements are arranged.

Further, the shape of the isolated area A2 viewed from the direction facing the surface 10S of the display body, that is, the planar shape of the periodic element is not limited to a square, and may be a rectangle, other polygons, or a circle. may

Even if the ratio of the width WT of the first dielectric layer 22 to the structural period PT and the ratio of the width WT of the second metal layer 42 to the structural period PT are different from 0.25 to 0.75, good. Further, the thickness relationship among the light shielding layer 10, the intermediate layer 11b, the first grating layer 21, the intermediate grating layer 31, and the second grating layer 41 may be different from the above embodiment.

(Second embodiment)
A second embodiment of a display and a method for manufacturing the display will be described with reference to FIGS. 9 to 13 . Below, the same code|symbol is attached|subjected about the structure similar to 1st Embodiment, and the description is abbreviate|omitted.

[Structure of Display]
As shown in FIG. 9, the first display region 10A of the display includes a light shielding layer 10, a supporting portion 11a, an intermediate layer 11b, a first grating layer 21, an intermediate grating layer 31, and a second grating layer 41. there is The support portion 11 a , the intermediate layer 11 b , the first grating layer 21 , the intermediate grating layer 31 and the second grating layer 41 are arranged in this order from the surface of the light shielding layer 10 .

The support portion 11a has a configuration similar to that of the first embodiment. FIG. 9 shows a configuration in which the light shielding layer 10 is formed on the surface opposite to the surface where the supporting portion 11a and the intermediate layer 11b are in contact with each other. In the structure in which the intermediate layer 11b and the first dielectric layer 22 are integrated, it is preferable that the refractive index of the material forming the intermediate layer 11b and the refractive index of the material forming the first dielectric layer 22 are close to each other. . The refractive index of each of the intermediate layer 11b and the first dielectric layer 22 is higher than that of the air layer, and is, for example, 1.2 or more and 1.7 or less.

[First grating layer 21]
The first grating layer 21 comprises a plurality of first dielectric layers 22 and a single first metal layer 23 . Each first dielectric layer 22 is located in the isolated area A2 when viewed from the direction facing the surface 10S of the display. The single first metal layer 23 is located in the peripheral area A3 when viewed from the direction facing the surface 10S. The plurality of first dielectric layers 22 are periodically arranged in an island-like arrangement along the surface 10S.

Each first dielectric layer 22 protrudes from the intermediate layer 11b, and each first dielectric layer 22 and the intermediate layer 11b are integral. When viewed from the direction facing the surface 10S, the structural period PT, which is the period at which the first dielectric layer 22 is positioned, is a sub-wavelength period equal to or shorter than the wavelength in the visible region. The first metal layer 23 is a mesh structure surrounding each first dielectric layer 22 when viewed from the direction facing the surface 10S. In the first grating layer 21, the first metal layer 23 is structurally and optically a sea component and each first dielectric layer 22 is structurally and optically an island component.

[Intermediate grating layer 31]
Intermediate lattice layer 31 comprises a plurality of first intermediate dielectric layers 32 and a single second intermediate dielectric layer 34 . Each first intermediate dielectric layer 32 is located in the isolated area A2 when viewed from the direction facing the surface 10S. A single second intermediate dielectric layer 34 is located in the peripheral region A3, viewed from the direction facing the surface 10S. The plurality of first intermediate dielectric layers 32 are periodically arranged in an island-like array along the surface 10S.

Each first intermediate dielectric layer 32 is a structure protruding from the first dielectric layer 22 . Each first intermediate dielectric layer 32 may be integral with the first dielectric layer 22 or separate from the first dielectric layer 22 . The period in which the first intermediate dielectric layers 32 are positioned when viewed from the direction facing the surface 10S is the structural period PT. The second intermediate dielectric layer 34 is a mesh structure surrounding each first intermediate dielectric layer 32 when viewed from the direction facing the surface 10S. The second intermediate dielectric layer 34 is separate from the first metal layer 23 . In the intermediate grating layer 31, the second intermediate dielectric layer 34 is structurally and optically a sea component and each first intermediate dielectric layer 32 is structurally and optically an island component.

[Second grating layer 41]
The second grating layer 41 comprises a plurality of second metal layers 42 and a single second dielectric layer 43 . Each second metal layer 42 is located in the isolated area A2 when viewed from the direction facing the surface 10S. A single second dielectric layer 43 is located in the peripheral region A3 when viewed from the direction facing the surface 10S. The plurality of second metal layers 42 are periodically arranged in an island-like arrangement along the surface 10S.

Each second metal layer 42 is a structure overlying the top surface of the first interlevel dielectric layer 32 . Each second metal layer 42 has a boundary with and is separate from the first interlevel dielectric layer 32 . The period at which the second metal layers 42 are positioned when viewed from the direction facing the surface 10S is the structural period PT. In the second grating layer 41, the second dielectric layer 43 is structurally and optically a sea component and each second metal layer 42 is structurally and optically an island component.

As shown in FIG. 10, in the peripheral region A3, the supporting portion 11a, the intermediate layer 11b, the first grating layer 21, the intermediate grating layer 31, and the second grating layer 41 are arranged in this order from the layer closest to the light shielding layer 10. To position.

As shown in FIG. 11, the second display region 10B does not include the intermediate layer 11b, the first lattice layer 21, the intermediate lattice layer 31, and the second lattice layer 41 on the light shielding layer 10. . That is, the second display region 10B transmits light in the visible region according to the light transmittance provided by the light shielding layer 10 and the support portion 11a.

[Material of each lattice layer]
The first dielectric layer 22 and the first intermediate dielectric layer 32 are dielectrics, and are made of, for example, a resin such as a photocurable resin or an inorganic material such as quartz. The refractive index of each of the first dielectric layer 22 and the first intermediate dielectric layer 32 is higher than that of the air layer, and is, for example, 1.2 or more and 1.7 or less.

The light shielding layer 10 is preferably made of a material that absorbs the visible wavelength band, such as a carbon-based black pigment or a titanium-based black pigment. Further, the light shielding layer 10 is preferably made of a material having a complex dielectric constant with a negative real part at wavelengths in the visible region, such as aluminum, silver, gold, indium, and tantalum.

The material forming the first metal layer 23 and the second metal layer 42 is preferably a material having a negative real part of the complex dielectric constant at wavelengths in the visible region, such as aluminum, silver, gold, indium, Tantalum or the like is preferred. The first metal layer 23 and the second metal layer 42 are made of, for example, the same material.

[Manufacturing method of display]
Next, an example of a method for manufacturing the display body of the second embodiment will be described.

Unlike the first embodiment, the light shielding layer 10 is formed on the surface opposite to the surface where the supporting portion 11a and the intermediate layer 11b contact each other. The forming method is, for example, a vacuum deposition method or a sputtering method.

A first dielectric layer 22, a first intermediate dielectric layer 32, a first metal layer 23, and a second metal layer 42 are then formed in the same manner as in the first embodiment. The first dielectric layer 22 and the first intermediate dielectric layer 32 are integrally formed as protrusions protruding from the surface of the intermediate layer 11b.

[Optical Configuration and Action of Display]
With reference to FIG. 12, the optical configuration and action of front reflection observation and back transmission observation in the display of the second embodiment will be described.

[Front reflection observation, back transmission observation]
As shown in FIG. 12, the white light L1 incident on the second grating layer 41 from the outside of the display enters the second grating layer 41 through the air layer, and then enters the intermediate grating layer 31 through the second grating layer 41 . The light L1 incident on the second grating layer 41 enters the second grating layer 41 having a refractive index close to that of the air layer through the air layer. Hard to come by. Further, the light incident on the intermediate grating layer 31 enters the intermediate grating layer 31 having a refractive index close to that of the air layer through the second grating layer 41 having a refractive index close to that of the air layer. Fresnel reflection is less likely to occur at the interface between the grating layer 41 and the intermediate grating layer 31 .

On the other hand, since the structural period PT of the second metal layer 42 is a sub-wavelength period equal to or shorter than the wavelength in the visible region, plasmon resonance occurs in the second lattice layer 41 . Plasmon resonance is a phenomenon in which part of the light incident on the second lattice layer 41 is coupled with collective vibration of electrons. Part of the light L<b>1 incident on the second grating layer 41 is converted into surface plasmons by plasmon resonance in the second grating layer 41 , and the surface plasmons pass through the second grating layer 41 . The surface plasmons transmitted through the second grating layer 41 are reconverted into light and emitted. The wavelength region of the light EP2 emitted by the second grating layer 41 due to plasmon resonance is a specific wavelength region depending on the grating structure including the structural period PT of the second metal layer 42 and the material. As a result, the second grating layer 41 transmits part of the wavelength region of the light incident on the second grating layer 41 to the intermediate grating layer 31 .

Further, since the structural period PT of the first dielectric layer 22 is also a sub-wavelength period equal to or shorter than the wavelength in the visible region, plasmon resonance also occurs in the first grating layer 21 . That is, part of the light incident on the first grating layer 21 is also converted into surface plasmons by plasmon resonance in the first grating layer 21, and the surface plasmons pass through the first grating layer 21 and are reconverted into light. emitted by The wavelength region of the light EP1 emitted by the first grating layer 21 due to plasmon resonance is a specific wavelength region depending on the grating structure including the structural period PT of the first dielectric layer 22 and the material. As a result, the first grating layer 21 transmits part of the wavelength region of the light incident on the first grating layer 21 to the intermediate layer 11b.

Further, part of the light incident on the intermediate layer 11b passes through the supporting portion 11a and enters the light shielding layer 10. FIG. The light EP1 emitted as light caused by plasmon resonance and the light shielding layer 10 cause plasmon resonance again, and only the light caused by resonance is reflected or transmitted.

As described above, according to the surface reflection observation in which the light L1 is incident on the second grating layer 41 from the outside of the display body and the surface 10S is observed from the surface side of the display body, Fresnel reflection hardly occurs at each interface. , causing plasmon resonance in each of the grating layers, and these together, black or a color close to black is visually recognized in the first display area 10A.

On the other hand, according to the rear transmission observation in which the light L1 is incident on the second grating layer 41 from the outside of the display body and the rear face 10T is observed from the rear face side of the display body, the light is transmitted through the plasmon resonance in each grating layer. The colored light LP1 is partially reflected or transmitted by plasmon resonance with the light shielding layer 10, and is visually recognized in the first display area 10A.

As a result, in rear transmission observation, the light shielding layer 10 blocks part of the colored light that has passed through the plasmon resonance in each grating layer, and a watermark effect can be obtained. The results of the front surface reflection observation and the back surface transmission observation show the same tendency even when the amount of external light toward the front surface 10S is higher than the amount of external light toward the back surface 10T.

[Back reflection observation, front transmission observation]
As shown in FIG. 13, white light L1 entering the light shielding layer 10 from the outside of the display enters the light shielding layer 10 through the air layer. The light L1 incident on the light shielding layer 10 having a higher refractive index than the air layer is reflected at the interface between the supporting portion 11a and the light shielding layer 10 . As described above, in the rear surface reflection observation, the light reflected by the light shielding layer 10 is visually recognized in the first display area 10A.

On the other hand, in the surface transmission observation in which the light L1 is incident on the support portion 11 from the outside of the display and the surface 10S is observed from the surface side of the display, the colored light passes through the plasmon resonance in the light shielding layer 10 and each lattice layer. LP2 is visually recognized in the first display area 10A. The results of the front surface transmission observation and the back surface reflection observation show the same tendency even when the amount of external light directed to the back surface 10T is higher than the amount of external light directed to the front surface 10S.

As described above, according to the second embodiment, in addition to the effects (1) to (6) of the first embodiment, the following effects can be obtained.
(7) Since the supporting portion 11a has the light shielding layer 10 on one surface of the supporting portion 11a that is not in contact with the intermediate layer 11b, Fresnel reflection occurring between the metal layer 42 or the metal layer 23 and the light shielding layer 10 is suppressed. As a result, the colors observed in surface reflection observation become clear.

<Modification of Second Embodiment>
The second embodiment can be implemented with the following modifications.
[Protective layer]
- Also in 2nd Embodiment, you may further provide a protective layer on the 2nd metal layer 42 like 1st Embodiment. At this time, the intensity of Fresnel reflection at the interface between the protective layer and the second metal layer 42 and the associated wavelength selectivity on the display vary depending on the refractive index of the protective layer. Therefore, the material constituting the protective layer is appropriately selected based on the wavelength range to be selected for the display.

It should be noted that as shown in FIG. 14, the protective layer 45 can be embodied as a structure integral with the second dielectric layer 43 and the second intermediate dielectric layer 33 . At this time, the protective layer 45 is preferably a resin layer with a low refractive index. The low-refractive-index resin layer has a refractive index closer to the refractive index of the air layer than the refractive index of the intermediate layer 11 b, the refractive index of the first dielectric layer 22 , or the refractive index of the first intermediate dielectric layer 32 .

As shown in FIG. 15, a recess 11H recessed from the surface of the intermediate layer 11b may be located in the isolated region A2. When viewed from the direction facing the surface 10S of the display body, the plurality of recesses 11H are arranged in a two-dimensional grid pattern having a sub-wavelength period. In such a configuration, the intermediate layer 11b is the periodic structure. That is, the periodic element of the periodic structure may be the concave portion 11H recessed from the reference plane, which is the surface of the intermediate layer 11b. Also in this case, the metal layer 61 has a shape that follows the surface shape of the periodic structure, and the dielectric layer 62 has a shape that follows the surface shape of the metal layer 61 . The first metal layer 23 is positioned in a mesh shape surrounding the opening of each recess 11H, and the second metal layer 42 is positioned on the bottom surface of each recess 11H. A mesh-like dielectric layer 71 is positioned on the first metal layer 23 , and a dielectric layer 72 arranged in a two-dimensional grid pattern is positioned on the second metal layer 42 . At this time, each second metal layer 42 and the mesh-like portion surrounding each second metal layer 42 in the intermediate layer 11b form a lattice structure composed of metal and dielectric. The dielectric layer 72 located on the second metal layer 42 and the first metal layer 23 also form a lattice structure made of metal and dielectric. Further, the light shielding layer 10 is positioned between the supporting portion 11a and the intermediate layer 11b, or on the surface of the supporting portion 11a opposite to the reference surface.

When the display is irradiated with light, plasmon resonance occurs in these layers having a lattice structure. The light generated by the plasmon resonance and the light shielding layer 10 cause plasmon resonance again, and the colors visually recognized in the surface reflection observation become clear in the first display area 10A, as in the above embodiment. In addition, a watermark effect can be obtained in rear surface transmission observation, and different colors are visually recognized in front surface reflection observation and rear surface transmission observation. Furthermore, in the rear surface reflection observation, an image reflected by the light shielding layer 10 is visually recognized. In the front surface transmission observation, a colored image is visually recognized through plasmon resonance in the light shielding layer 10 and each lattice structure, and different colors are visually recognized in the rear surface reflection observation and the front surface transmission observation.

Even when the periodic element is the concave portion 11H, the ratio of the area occupied by the periodic element per unit area on the plane including the reference plane and the periodic element is more than 0.1 and less than 0.5. preferable. If the ratio of the area is within the above range, the metal layer 61 and the dielectric layer 62 are likely to be formed in a shape that follows the uneven shape of the surface of the periodic structure. Further, if the ratio of the area is within the above range, the durability of the periodic structure is enhanced, and it is easy to obtain the machining accuracy of the concave portion 11H. Also in the display of the first embodiment, the periodic element may be the concave portion 11H recessed from the reference plane.

The above-described coloring structure and its manufacturing method will be described using specific examples.

First, a mold, which is an intaglio used in photo-nanoimprinting, was prepared. Specifically, a film made of chromium (Cr) was formed on the surface of the synthetic quartz substrate by sputtering to a thickness of 10 nm, and an electron beam resist pattern was formed on the Cr film by electron beam lithography. The resist used was of positive type and had a film thickness of 150 nm. The formed pattern is a pattern in which squares with a side length of 160 nm are arranged in a hexagonal array with a structural period PT of 320 nm in a square region with a side length of 1 cm. Inner area.

Next, the Cr film exposed from the resist was etched by plasma generated by applying a high frequency to a mixed gas of chlorine and oxygen. Subsequently, the region of the synthetic quartz substrate exposed from the resist and the Cr film was etched by plasma generated by applying high frequency to ethane hexafluoride gas. The synthetic quartz substrate thus etched had a depth of 100 nm. The remaining resist and Cr film were removed to obtain a mold having an uneven structure. OPTOOL HD-1100 (manufactured by Daikin Industries, Ltd.) was applied as a release agent to the surface of the mold.

Next, a film made of aluminum (Al) was formed to a thickness of 25 nm using a vacuum deposition method on one side of a polyethylene terephthalate film that had been subjected to an easy-adhesion treatment on one side, which was to serve as a base material for the structural coloring body. Thus, a light shielding layer was obtained.

Next, an ultraviolet curable resin was applied to the surface on which the pattern of the mold was formed. The polyethylene terephthalate film having the light shielding layer formed on one side was used to cover the surface of the mold with the light shielding layer formed thereon. Furthermore, the ultraviolet curable resin is spread using a roller so that the ultraviolet curable resin spreads over the entire area of the mold where the pattern is formed. The terephthalate film was peeled off. As a result, a pattern of protrusions arranged in a hexagonal arrangement is formed on the surface of the UV-curable resin, and a layer made of this UV-curable resin, a light-shielding layer made of aluminum (Al), and a substrate made of a polyethylene terephthalate film. A periodic structure as a laminate was obtained. The refractive index of the UV curable resin after curing was 1.52.

Next, a metal layer was formed by forming a film made of aluminum (Al) to a thickness of 25 nm on the surface of the periodic structure using a vacuum deposition method. Thus, a display body of Example was obtained. The display of the example corresponds to the display of the first embodiment. The side on which the dielectric layer is positioned with respect to the base material is the front side of the display body, and the side on which the base material is positioned with respect to the dielectric layer is the rear side of the display body.

When the display member of the example was irradiated with white light and observed, in the region where the pattern of the convex portions was formed, a green color close to black was observed by surface reflection observation, and aluminum (Al) was observed by rear surface reflection observation. ) was observed, and a yellow to yellow-green color was observed by observance of the front surface transmission and rear surface transmission observation. In addition, in the region where the convex pattern was not formed, a color with metallic luster was observed as reflected light from the metal layer made of aluminum.

INDUSTRIAL APPLICABILITY The present invention can be used for a display used for preventing counterfeiting and improving designability.

A2... Isolated area, A3... Peripheral area, L1, EP1, EP2, LR, LP1, LP2... Light, LT... Square, PT... Structural period, WT... Width, WP... Shortest width, 10A... First display area, 10B Second display region 10S Front surface 10T Back surface 11a Supporting portion 11b Intermediate layer 11T Convex portion 11H Concave portion 21 First lattice layer 22 First dielectric layer 23 First metal layer 31 Intermediate lattice layer 32 First intermediate dielectric layer 33 Second intermediate dielectric layer 41 Second lattice layer 42 Second metal layer 43 Second dielectric layer , 45... Protective layer, 61... Metal layer, 62... Dielectric layer

Claims (8)

A supporting portion having a reference plane, and a plurality of periodic elements arranged in a two-dimensional lattice pattern having a sub-wavelength period on the reference plane, the projections protruding from the reference plane or the recesses recessed from the reference plane. a periodic structure body that is a dielectric comprising the periodic element that is any one;
A metal positioned on the surface of the periodic structure, which is a plane including the area surrounding the periodic element in the reference plane and the surface of the periodic element, and having a shape following the surface shape of the periodic structure. comprising a layer and
on the reference plane,
a first lattice layer having a thickness of 10 nm or more and 200 nm or less;
a second lattice layer provided above the first lattice layer and having a thickness of 10 nm or more and 200 nm or less;
an intermediate lattice layer thicker than the first lattice layer and the second lattice layer, the intermediate lattice layer sandwiched between the first lattice layer and the second lattice layer in a thickness direction;
A light shielding layer is provided between the reference surface of the support portion and the first lattice layer, or on the surface of the support portion opposite to the reference surface,
The first lattice layer includes a plurality of first dielectric layers periodically arranged in an island-like arrangement, and a mesh-like first metal layer surrounding each first dielectric layer,
The intermediate lattice layer has a plurality of first intermediate dielectric layers arranged periodically in an island-like arrangement and a mesh shape surrounding each first intermediate dielectric layer, and a second intermediate dielectric layer having a low dielectric constant;
The second lattice layer includes a plurality of second metal layers periodically arranged in an island-like arrangement, and a mesh-like second dielectric layer surrounding each second metal layer,
the periodic element is composed of the first dielectric layer and the first intermediate dielectric layer, and the metal layer includes the first metal layer and the second metal layer;
A display member, wherein the light shielding layer is made of a metal material having a negative real part of a complex permittivity with respect to light in the visible region. The volume ratio of the first metal layer in the first lattice layer is greater than the volume ratio of the second metal layer in the second lattice layer, and the volume ratio of the second metal layer in the second lattice layer is greater than the volume fraction of the metal material in the intermediate lattice layer,
A ratio of the width of the first dielectric layer to the structure period of the first dielectric layer and a ratio of the width of the second metal layer to the structure period of the second metal layer are 0.25 or more and 0.75. and
2. The display according to claim 1, wherein said first metal layer and said second metal layer are made of a material having a negative real part of a complex permittivity with respect to light in the visible region. A ratio of the width of the first dielectric layer to the structure period of the first dielectric layer and a ratio of the width of the second metal layer to the structure period of the second metal layer are 0.40 or more and 0.60. 3. A display according to claim 1 or 2, wherein: The thickness of the first lattice layer is 100 nm or less,
the second lattice layer has a thickness of 100 nm or less;
The display according to any one of claims 1 to 3, wherein the intermediate lattice layer has a thickness of 150 nm or less. The first grating layer and the support are made of the same material,
The display according to any one of claims 1 to 4, wherein the total thickness of said first grating layer and said supporting portion is 50 nm or more and 500 nm or less. The light shielding layer is made of the same material as the first metal layer and the second metal layer,
the second dielectric layer is an air layer,
The difference between the refractive index of the first dielectric layer and the refractive index of the first metal layer is larger than the difference between the refractive index of the second dielectric layer and the second metal layer. 6. The display body according to any one of 1 to 5. wherein the first dielectric layer and the first intermediate dielectric layer are an integral structure;
The display according to any one of claims 1 to 6, wherein said second intermediate dielectric layer and said second dielectric layer are an integral structure. 8. The dielectric layer according to any one of claims 1 to 7, which is located on the surface of the metal layer opposite to the surface in contact with the periodic structure and has a shape following the surface shape of the metal layer. The display body described in .

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