阅读说明：本技术 显示体 (Display body ) 是由 久保田正志 于 2020-02-19 设计创作，主要内容包括：提供一种能够在短时间内制造对构造色的图像进行显示的显示体的技术。本发明的显示体(1A)包含：多层膜(13),其包含层叠体,该层叠体由折射率不同的大于或等于2个的电介质层(13a、13b)构成,在一个主面具有大于或等于1个的凹部(RR、RG、RB)；以及大于或等于1个的反射面,其分别与所述层叠体的另一个主面相对,使在使得可见区域内的光射入至所述多层膜(13)的情况下从所述另一个主面射出的光,以与该光的射出角不同的入射角射入至所述另一个主面。(Provided is a technology capable of manufacturing a display body for displaying an image of a structural color in a short time. The display body (1A) of the present invention comprises: a multilayer film (13) comprising a laminate composed of dielectric layers (13a, 13b) having 2 or more different refractive indices and having 1 or more recesses (RR, RG, RB) on one main surface; and 1 or more reflecting surfaces that face the other main surface of the laminate, respectively, and that cause light that exits from the other main surface when light in the visible region enters the multilayer film (13) to enter the other main surface at an incident angle that is different from the exit angle of the light.)

1. A display body, wherein,

the display body has:

a multilayer film comprising a laminate composed of 2 or more dielectric layers having different refractive indices, and having 1 or more recessed portions on one main surface; and

and 1 or more reflecting surfaces facing the other main surface of the multilayer body, respectively, and configured to allow light emitted from the other main surface to enter the other main surface at an incident angle different from an exit angle of the light when the light in the visible region enters the multilayer film.

2. The display according to claim 1,

the reflection surfaces of 1 or more include diffraction gratings, respectively.

3. The display according to claim 1,

the 1 or more recesses include 1 st and 2 nd recesses having different depths.

4. The display according to claim 3,

the greater than or equal to 1 reflecting surface includes:

a 1 st reflecting surface provided with a 1 st diffraction grating and having visible light transmittance; and

and a 2 nd reflection surface provided with a 2 nd diffraction grating having a lattice constant different from that of the 1 st diffraction grating, and facing the other main surface of the laminate with the 1 st reflection surface interposed therebetween.

5. The display according to claim 3,

the 1 or more reflection surfaces include reflection surfaces provided with 1 st and 2 nd diffraction gratings at positions corresponding to the 1 st and 2 nd recesses, respectively, and the 1 st and 2 nd diffraction gratings have different lattice constants from each other.

6. An article with a display, wherein,

the article with a display comprises:

the display of any one of claims 1 to 5; and

and an article for supporting the display body.

7. A blank medium for recording an image by laser beam irradiation, wherein,

the blank medium has:

a laminate body which is composed of 2 or more dielectric layers having different refractive indices and in which 1 or more recesses are formed on one main surface by the laser beam irradiation; and

and 1 or more reflecting surfaces facing the other main surface of the laminate, respectively, so that light in a visible region emitted from the other main surface enters the other main surface at an incident angle different from an emission angle thereof.

8. The blank medium of claim 7,

the reflection surfaces of 1 or more include diffraction gratings.

9. The blank medium of claim 8,

the greater than or equal to 1 reflecting surface includes:

a 1 st reflecting surface provided with a 1 st diffraction grating and having visible light transmittance; and

and a 2 nd reflection surface provided with a 2 nd diffraction grating having a lattice constant different from that of the 1 st diffraction grating, and facing the other main surface of the laminate with the 1 st reflection surface interposed therebetween.

10. The blank medium of claim 8,

the number of the reflection surfaces is 1 or more, and the reflection surfaces include reflection surfaces provided with 1 st and 2 nd diffraction gratings, and lattice constants of the 1 st and 2 nd diffraction gratings are different from each other.

11. An article with a blank medium, wherein,

the article with blank media comprises:

the blank medium of any one of claims 7 to 10; and

an article supporting the blank media.

12. A method for manufacturing a display body, wherein,

a step of forming the 1 or more concave portions by irradiating the laser beam to the blank medium according to any one of claims 7 to 10.

13. A method for manufacturing an article with a display body, wherein,

the method for manufacturing the article with the display body comprises the following steps:

a step of manufacturing a display body by the method according to claim 12; and

and supporting the display body on an article.

14. A method for manufacturing an article with a display body, wherein,

a step of forming the 1 or more recesses by irradiating the blank medium of the blank medium-carrying article according to claim 11 with the laser beam.

Technical Field

The present invention relates to a display body.

Background

Currently, holograms that are difficult to counterfeit and copy are used for the purpose of proving that an article is genuine. For example, if a transparent film containing a hologram is attached to a card on which personal information such as a face image is recorded, the personal information can be protected from tampering. In addition, if a hologram is used for paper money or securities, the above-mentioned improper duplication can be suppressed. In recent years, it has been proposed to record a face image using a hologram on an id (identification) card or the like (patent documents 1 and 2).

Patent document 1: japanese patent laid-open publication No. 2014-8746

Patent document 2: japanese patent laid-open No. 2014-16418

Disclosure of Invention

As described above, the hologram itself is difficult to forge and copy, and therefore, is used for various articles for which it is desired to suppress improper copying.

However, when an image such as a face image is recorded on a blank medium using a hologram as needed, the hologram needs to be transferred to the blank medium in units of pixels, for example. Therefore, in order to manufacture a plurality of display bodies in a short time by this method, it is necessary to operate a plurality of manufacturing apparatuses in parallel.

Accordingly, an object of the present invention is to provide a technique capable of manufacturing a display body displaying an image of a structural color in a short time.

According to a 1 st aspect of the present invention, there is provided a display body having: a multilayer film comprising a laminate composed of 2 or more dielectric layers having different refractive indices, and having 1 or more recessed portions on one main surface; and 1 or more reflective surfaces that face the other main surface of the laminate, respectively, and that cause light that exits from the other main surface to enter the other main surface at an incident angle that is different from an exit angle of the light when the light in the visible region enters the multilayer film. Here, the "visible region" means a wavelength range of 350 to 750 nm.

According to the 2 nd aspect of the present invention, there is provided an article with a display body, comprising the display body according to the 1 st aspect and an article supporting the display body.

According to the 3 rd aspect of the present invention, there is provided a blank medium for recording an image by laser beam irradiation, comprising: a laminate body which is composed of 2 or more dielectric layers having different refractive indices and in which 1 or more recesses are formed on one main surface by the laser beam irradiation; and 1 or more reflecting surfaces facing the other main surface of the laminate, respectively, and configured to allow light in a visible region emitted from the other main surface to enter the other main surface at an incident angle different from an emission angle thereof.

According to the 4 th aspect of the present invention, there is provided an article with a blank medium, comprising the blank medium according to the 3 rd aspect and an article supporting the blank medium.

According to the 5 th aspect of the present invention, there is provided a method for manufacturing a display body, comprising the step of forming the 1 or more concave portions by irradiating the blank medium according to the 3 rd aspect with the laser beam.

According to the 6 th aspect of the present invention, there is provided a method for manufacturing an article with a display body, comprising a step of manufacturing the display body by the method according to the 5 th aspect, and a step of supporting the display body on the article.

According to the 7 th aspect of the present invention, there is provided a method for manufacturing an article with a display, comprising the step of forming the 1 or more recessed portions by irradiating the blank medium of the article with a blank medium according to the 4 th aspect with the laser beam.

Drawings

Fig. 1 is a sectional view schematically showing a display body according to embodiment 1 of the present invention.

Fig. 2 is a cross-sectional view schematically showing a blank medium that can be used for manufacturing the display shown in fig. 1.

Fig. 3 is a sectional view illustrating a method of manufacturing the display shown in fig. 1.

Fig. 4 is a cross-sectional view schematically showing an optical operation that occurs when a display according to a comparative example is illuminated with white light.

Fig. 5 is a cross-sectional view schematically showing an optical operation that occurs when the display body shown in fig. 1 is illuminated with white light.

Fig. 6 is a sectional view schematically showing a display according to embodiment 2 of the present invention.

FIG. 7 is a sectional view schematically showing a blank medium used for manufacturing the display shown in FIG. 6.

Fig. 8 is a sectional view schematically showing an article with a display according to an embodiment of the present invention.

Fig. 9 is a sectional view schematically showing an article with a blank medium according to an embodiment of the present invention.

Fig. 10 is a graph showing an example of a transmission spectrum obtained by computer simulation for a portion of the multilayer film corresponding to the recess.

Fig. 11 is a graph showing another example of a transmission spectrum obtained by computer simulation for a portion of the multilayer film corresponding to the recess.

Fig. 12 is a graph showing still another example of the transmission spectrum obtained by computer simulation for the portion of the multilayer film corresponding to the concave portion.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals are given to elements having the same or similar functions, and redundant description is omitted.

Fig. 1 is a sectional view schematically showing a display body according to embodiment 1 of the present invention.

The display 1A includes a multilayer film 13, front surface layers 11R, 11G, and 11B, reflective layers 12R, 12G, and 12B, and back surface layers 14R, 14G, and 14B. The multilayer film 13 side of the display 1A is a front surface, and the reverse side thereof is a back surface. Hereinafter, of the 2 main surfaces of each layer, a surface closer to the front surface of the display 1A is referred to as a front surface, and a surface closer to the back surface of the display 1A is referred to as a back surface.

The multilayer film 13 is a dielectric multilayer film including a laminate composed of 2 or more dielectric layers having different refractive indices. Here, the multilayer film 13 is composed of a laminate in which dielectric layers 13a and 13b having different refractive indices are alternately laminated. As described later, the multilayer film 13 may further include a protective layer covering the front surface of the laminate. The protective layer may have a single-layer structure or a multi-layer structure.

The thickness of each layer constituting the multilayer film 13 is, for example, in the range of 5nm to 500 μm.

As a material for each layer constituting the multilayer film 13, for example, a transparent dielectric such as zinc sulfide or titanium dioxide can be used. Here, the multilayer film 13 may be constituted by 2 kinds of dielectric layers 13a and 13b having different refractive indices (materials), and the multilayer film 13 may be constituted by 3 or more kinds of dielectric layers having different refractive indices (materials).

The 1 st, 2 nd, and 3 rd recesses RR, RG, and RB are provided on the front surface of the laminate as 1 or more recesses. Here, the 1 st recessed portion RR, the 2 nd recessed portion RG, and the 3 rd recessed portion RB are provided in the layer located on the outermost surface of the stacked body among the dielectric layers 13 a. The 3 rd recess RB may be omitted. In addition, the 2 nd recessed portion RG may be omitted.

The depths of the 1 st, 2 nd, and 3 rd recess portions RR, RG, and RB are different from each other. Here, the depth may be made shallower in the order of the 1 st recessed portion RR, the 2 nd recessed portion RG, and the 3 rd recessed portion RB, and either one of them may be made shallowest, and either one may be made deepest.

In fig. 1, in order to easily understand the difference in the depth of the recess, the dielectric layer 13a on the front-most surface side may be drawn thicker than the other dielectric layers 13a and 13 b. The dielectric layer 13a on the front-most surface side may have the same thickness as that of any of the other dielectric layers 13a and 13b, or may be thinner than that.

When white light is made incident at the 1 st incident angle, the multilayer film 13 exhibits a high transmittance or a low transmittance in the entire visible region, for example, at a position where the concave portion is not provided. Here, as an example, when white light is made incident at the 1 st incident angle, the multilayer film 13 exhibits a low transmittance over the entire visible region at a position where the concave portion is not provided. Further, "white light" is light having substantially equal intensity over the entire visible region.

The 1 st portion corresponding to the 1 st recessed portion RR, the 2 nd portion corresponding to the 2 nd recessed portion RG, the 3 rd portion corresponding to the 3 rd recessed portion RB, and the portion where no recessed portion is provided in the multilayer film 13 exhibit different transmission spectra when white light is caused to enter at the 1 st incident angle. The 1 st to 3 rd portions are different in wavelength from each other in which the maximum or minimum transmittance is exhibited in the visible region when white light is caused to enter at the 1 st incident angle.

For example, in the transmission spectrum when white light is incident on the multilayer film 13 at the 1 st incident angle, in the 1 st portion corresponding to the 1 st recess RR, the ratio of the transmittance in the 1 st wavelength range to the transmittance in the other wavelength ranges is larger than that in the portion where no recess is provided, and the maximum transmittance is exhibited at the 1 st wavelength in the 1 st wavelength range. In this case, with respect to the transmission spectrum in the case where white light is incident on the multilayer film 13 at the 1 st incident angle, in the 2 nd portion corresponding to the 2 nd recessed portion RG, for example, the ratio of the transmittance in the 2 nd wavelength range to the transmittance in the other wavelength range is larger than that in the portion where no recessed portion is provided, and the maximum transmittance is exhibited at the 2 nd wavelength in the 2 nd wavelength range. In this case, regarding the transmission spectrum in the case where white light is incident on the multilayer film 13 at the 1 st incident angle, the transmittance in the 3 rd portion corresponding to the 3 rd recessed portion RB is, for example, greater than the transmittance in the 3 rd wavelength range and the transmittance in the other wavelength range than the portion where the recessed portion is not provided, and the maximum transmittance is exhibited at the 3 rd wavelength in the 3 rd wavelength range.

Alternatively, in the transmission spectrum when white light is incident on the multilayer film 13 at the 1 st incident angle, in the 1 st portion corresponding to the 1 st recess RR, the ratio of the transmittance in the 1 st wavelength range to the transmittance in the other wavelength ranges is smaller than that in the portion where no recess is provided, and the minimum transmittance is exhibited at the 1 st wavelength in the 1 st wavelength range. In this case, with respect to the transmission spectrum in the case where white light is incident on the multilayer film 13 at the 1 st incident angle, in the 2 nd portion corresponding to the 2 nd recessed portion RG, for example, the ratio of the transmittance in the 2 nd wavelength range to the transmittance in the other wavelength range is smaller than that in the portion where no recessed portion is provided, and the minimum transmittance is exhibited at the 2 nd wavelength in the 2 nd wavelength range. In this case, regarding the transmission spectrum in the case of injecting the white light into the multilayer film 13 at the 1 st incident angle, in the 3 rd portion corresponding to the 3 rd recessed portion RB, for example, the ratio of the transmittance in the 3 rd wavelength range to the transmittance in the other wavelength range is smaller than that in the portion where the recessed portion is not provided, and the minimum transmittance is exhibited at the 3 rd wavelength in the 3 rd wavelength range.

Here, as an example, the former structure is adopted for the multilayer film 13.

The 1 st to 3 rd wavelength ranges are mutually different wavelength ranges within the visible region. For example, the longest wavelength of the 2 nd wavelength range is shorter than the shortest wavelength of the 1 st wavelength range, and the longest wavelength of the 3 rd wavelength range is shorter than the shortest wavelength of the 2 nd wavelength range. Here, as an example, the 1 st, 2 nd, and 3 rd wavelength ranges are red, green, and blue wavelength ranges, respectively.

The front surface layer 11R, the reflective layer 12R, and the back surface layer 14R are laminated in this order on the back surface of the multilayer film 13. Front surface layer 11G, reflection layer 12G, and back surface layer 14G are stacked on back surface layer 14R in this order. Front surface layer 11B, reflection layer 12B, and back surface layer 14B are stacked on back surface layer 14G in this order.

The front surface layers 11R, 11G, and 11B are each made of, for example, a transparent resin. The transparent resin may be a cured product of a thermosetting resin or a photocurable resin, a thermoplastic resin, an adhesive, or a pressure-sensitive adhesive. The above layers may have a single-layer structure or a multi-layer structure.

The 1 st, 2 nd and 3 rd relief structures are provided on the back surfaces of the front surface layers 11R, 11G and 11B, respectively. In the 1 st, 2 nd, and 3 rd relief structures, when white light is incident on the multilayer film 13 at the 1 st incident angle, the 1 st reflective surface, which is the interface between the front surface layer 11R and the reflective layer 12R, the 2 nd reflective surface, which is the interface between the front surface layer 11G and the reflective layer 12G, and the 3 rd reflective surface, which is the interface between the front surface layer 11B and the reflective layer 12B, light emitted from the rear surface of the multilayer film 13 is incident on the rear surface of the multilayer film 13 at the 2 nd incident angle different from the emission angle of the light.

Here, the 1 st relief structure causes the 1 st reflective surface to produce a 1 st blazed diffraction grating, the 2 nd relief structure causes the 2 nd reflective surface to produce a 2 nd blazed diffraction grating, and the 3 rd relief structure causes the 3 rd reflective surface to produce a 1 st blazed diffraction grating. The arrangement directions of the grooves or the ridges constituting the 1 st to 3 rd blazed diffraction gratings are parallel to each other. Here, the arrangement direction of the grooves or the ribs is parallel to the Y direction. In addition, the spatial frequencies of the grating lines of the 1 st to 3 rd blazed diffraction gratings are different from each other. Here, the spatial frequency of the grating line of the 1 st blazed diffraction grating is the smallest, and the spatial frequency of the grating line of the 3 rd blazed diffraction grating is the largest. The magnitude relationship of the spatial frequencies of the grating lines between the 1 st to 3 rd blazed diffraction gratings may also be different from this.

The 1 st blazed diffraction grating defines a blazed angle and a lattice constant (line interval) such that, when white light is incident on the multilayer film 13 at the 1 st incident angle, light (light of the 1 st wavelength) transmitted through the 1 st portion of the multilayer film 13 corresponding to the 1 st recessed portion RR is incident on the multilayer film 13 again at the 2 nd incident angle. When the light of the 1 st wavelength is red light, the spatial frequency of the grating lines constituting the 1 st blazed diffraction grating is, for example, in the range of 950 to 2050 lines/mm. The blaze angle of the 1 st blazed diffraction grating is set to be, for example, in the range of 1 ° to 89 °.

The 2 nd blazed diffraction grating defines a blazed angle and a lattice constant such that, when white light is incident on the multilayer film 13 at the 1 st incident angle, light (light of the 2 nd wavelength) transmitted from the 2 nd portion of the multilayer film 13 corresponding to the 2 nd recessed portion RG is incident again on the multilayer film 13 at the 2 nd incident angle. When the light of the 2 nd wavelength is green light, the spatial frequency of the grating lines constituting the 2 nd blazed diffraction grating is set to be, for example, in the range of 950 to 2050 bars/mm. The blaze angle of the 2 nd blazed diffraction grating is equal to the blaze angle of the 1 st blazed diffraction grating, for example.

The 3 rd blazed diffraction grating defines a blaze angle and a lattice constant such that, when white light is incident on the multilayer film 13 at the 1 st incident angle, light (light of the 3 rd wavelength) transmitted through the 3 rd portion of the multilayer film 13 corresponding to the 3 rd recessed portion RB is incident on the multilayer film 13 again at the 2 nd incident angle. When the 3 rd wavelength light is blue light, the spatial frequency of the grating lines constituting the 3 rd blazed diffraction grating is set to be, for example, in the range of 950 to 2050 stripes/mm. The blaze angle of the 3 rd blazed diffraction grating is equal to the blaze angle of the 1 st blazed diffraction grating, for example.

The structure in which the 1 st to 3 rd relief structures generate the interface may be a diffraction grating other than a blazed diffraction grating. In the case where the 1 st to 3 rd relief structures cause the interface to be a diffraction grating other than a blazed diffraction grating, and the 1 st, 2 nd, and 3 rd wavelengths of light are red light, green light, and blue light, respectively, the lattice constant of the diffraction grating is set to be, for example, within the above range of the blazed diffraction grating.

In the structure in which the 1 st to 3 rd relief structures generate the above-described interfaces, if the light transmitted through the multilayer film 13 can be made incident again on the multilayer film 13 at the 2 nd incident angle in the case where the white light is made incident on the multilayer film 13 at the 1 st incident angle, the structure may not have a function as a diffraction grating.

The reflective layers 12R, 12G, and 12B cover the back surfaces of the front surface layers 11R, 11G, and 11B, respectively.

The reflective layers 12R and 12G are made of a transparent material. The front surface layers 11R and 11G of the reflective layers 12R and 12G have different refractive indices. As the reflective layers 12R and 12G, for example, materials exemplified for the dielectric layers 13a and 13b can be used.

The reflective layer 12B is made of a transparent material or an opaque material. In the case where the reflective layer 12B is made of a transparent material, its refractive index is different from that of the front surface layer 11B. As the transparent material, for example, the materials exemplified for the dielectric layers 13a and 13b can be used. As the opaque material, for example, a metal material such as aluminum, silver, and an alloy containing 1 or more of the above metals can be used.

The reflective layers 12R, 12G, and 12B may have a single-layer structure or a multilayer structure.

The back surface layers 14R, 14G, and 14B cover the back surfaces of the reflective layers 12R, 12G, and 12B, respectively. The back layers 14R, 14G, and 14B are each made of, for example, a transparent resin. The back layer 14B may also be opaque. The resin constituting each of the back layers 14R, 14G, and 14B may be a cured product of a thermosetting resin or a photocurable resin, may be a thermoplastic resin, or may be an adhesive or an adhesive.

The front surface layer 11B, the reflective layer 12B, and the back surface layer 14B may be omitted. The front surface layer 11G, the reflection layer 12G, and the back surface layer 14G may be omitted.

1 or 2 of the front surface layer 11R, the reflective layer 12R, and the back surface layer 14R may be omitted. However, when only the reflection layer 12R is omitted, materials having different refractive indices are used for the front surface layer 11R and the back surface layer 14R.

Likewise, 1 or 2 of the front surface layer 11G, the reflection layer 12G, and the back surface layer 14G may be omitted. However, when only the reflection layer 12G is omitted, materials having different refractive indices are used for the front surface layer 11G and the back surface layer 14G.

Likewise, 1 or 2 of the front surface layer 11B, the reflective layer 12B, and the back surface layer 14B may be omitted. However, when only the reflection layer 12B is omitted, materials having different refractive indices are used for the front surface layer 11B and the back surface layer 14B.

Next, a method for manufacturing the display 1A will be described.

Fig. 2 is a cross-sectional view schematically showing a blank medium that can be used for manufacturing the display shown in fig. 1. Fig. 3 is a sectional view illustrating a method of manufacturing the display shown in fig. 1. In fig. 3, reference symbol OL denotes an objective lens of the laser device.

In manufacturing the display 1A, first, a blank medium 1A0 shown in fig. 2 is prepared. The blank medium 1A0 has the same structure as the display 1A except that the 1 st, 2 nd, and 3 rd concave portions RR, RG, and RB are not provided in the laminate.

Next, an image is recorded by laser beam irradiation to the laminated body. Specifically, the laser beam LB is irradiated to the region of the front surface of the laminate where the 1 st recessed portion RR, the 2 nd recessed portion RG, and the 3 rd recessed portion RB are to be formed. Thereby, the 1 st, 2 nd, and 3 rd concave portions RR, RG, and RB are formed on the front surface of the laminate.

The beam spot is typically several 10 μm in diameter. Therefore, by the laser beam irradiation, for example, a concave portion having an opening diameter of several 10 μm or more can be formed. In addition, the depth of the concave portion formed by irradiation of the laser beam LB may be adjusted by changing the number of times of irradiation of pulsed light, for example, in the case where the laser device is a pulsed laser. The display 1A was obtained in the above manner.

Next, the optical effect of the display 1A will be described.

Fig. 4 is a cross-sectional view schematically showing an optical operation that occurs when a display according to a comparative example is illuminated with white light. Fig. 4 shows a display in which a flat reflecting surface REF is provided on the back surface side of the multilayer film 13 provided with the 1 st recess RR, the 2 nd recess RG, and the 3 rd recess RB, in place of the 1 st to 3 rd reflecting surfaces, in parallel with the back surface of the multilayer film 13 and apart from the multilayer film 13.

Here, for easy understanding, the display body is designed in the following manner. That is, when the front surface of the display is illuminated with the white light L1 emitted from the light source LS, all light components of the white light incident at the 1 st incident angle θ 1 in the portion of the multilayer film 13 where no recess is provided interfere with each other in a reduced manner, and are not transmitted through the multilayer film 13 and are not reflected by the multilayer film 13. In the 1 st portion of the multilayer film 13 corresponding to the 1 st recess RR, light L2 having the 1 st wavelength in the red range among white light incident at the 1 st incident angle θ 1 is transmitted through the multilayer film 13, and light having other wavelengths interfere with each other in a mutually attenuated manner, and is not transmitted through the multilayer film 13 or reflected by the multilayer film 13. In the 2 nd portion of the multilayer film 13 corresponding to the 2 nd recessed portion RG, light having the 2 nd wavelength in the green range among white light incident at the 1 st incident angle θ 1 is transmitted through the multilayer film 13, and light having other wavelengths interfere with each other in a mutually attenuated manner, and is not transmitted through the multilayer film 13, and is not reflected by the multilayer film 13. In the 3 rd portion corresponding to the 3 rd recess RB in the multilayer film 13, light having the 3 rd wavelength in the blue range among the white light incident at the 1 st incident angle θ 1 is transmitted through the multilayer film 13, and light having other wavelengths interfere with each other in a mutually attenuated manner, and are not transmitted through the multilayer film 13, and are not reflected by the multilayer film 13.

As described above, the 1 st portion corresponding to the 1 st recess RR transmits the light L2 having the 1 st wavelength in the red range in the white light L1 incident on the multilayer film 13 at the 1 st incident angle θ 1, and does not transmit the light having the other wavelengths and does not reflect the light. The light L2 as the transmitted light is reflected by the reflecting surface REF. Since the reflecting surface REF is provided parallel to the back surface of the multilayer film 13, the light L2 as the reflected light is regularly reflected by the reflecting surface REF. As a result, the light L2 is incident again on the multilayer film 13 at an incident angle equal to the emission angle.

Generally, the position of the light source LS is different from the position of the observer OB. Therefore, the 1 st incident angle θ 1 is larger than 0 °, and the output angle is also larger than 0 °. Therefore, the light L2 as reflected light may enter a portion other than the 1-th portion in the multilayer film 13, for example, the 3 rd portion corresponding to the 3 rd recessed portion RB again.

As described above, in the 3 rd portion, light having the 3 rd wavelength in the blue range among the white light incident at the 1 st incident angle θ 1 is transmitted through the multilayer film 13, but light having other wavelengths interfere with each other in a mutually attenuated manner and are not transmitted through the multilayer film 13. Also here, the light L2 has the 1 st wavelength in the red range.

Thus, the light L2 cannot be transmitted through the multilayer film 13. Therefore, the display cannot display the original image to the observer OB.

Fig. 5 is a cross-sectional view schematically showing an optical operation that occurs when the display body shown in fig. 1 is illuminated with white light. In fig. 5, for the sake of simplicity, only the 1 st reflecting surface DG is depicted as a structure provided on the rear surface side of the multilayer film 13. Here, for easy understanding, the multilayer film 13 is also designed in the same manner as the structure described with reference to fig. 4.

In this display, the 1 st portion corresponding to the 1 st recess RR transmits the light L2 having the 1 st wavelength in the red range among the white light L1 incident on the multilayer film 13 at the 1 st incident angle θ 1, does not transmit light having other wavelengths, and does not reflect the light. The light L2 as the transmitted light enters the 1 st reflecting surface DG.

The 1 st reflecting surface DG constitutes a 1 st blazed diffraction grating. As described above, the 1 st blazed diffraction grating diffracts the 1 st wavelength light L2 transmitted from the 1 st portion of the multilayer film 13 corresponding to the 1 st recess RR to be incident again on the multilayer film 13 at the 2 nd incident angle θ 2 as the light L3.

The transmission characteristic of the multilayer film 13 varies depending on the incident angle of incident light. For example, the 2 nd portion corresponding to the 2 nd recessed portion RG and the 3 rd portion corresponding to the 3 rd recessed portion RB in the multilayer film 13 do not transmit the 1 st wavelength light L2 incident at the 1 st incident angle θ 1. However, the above portion may transmit the light L3 of the 1 st wavelength incident at the 2 nd incident angle θ 2 different from the 1 st incident angle θ 1. In addition, the other portions of the multilayer film 13 may transmit the light L3 of the 1 st wavelength incident at the 2 nd incident angle θ 2.

Therefore, if the multilayer film 13 is designed such that the light L3 of the 1 st wavelength incident at the 2 nd incident angle θ 2 is transmitted through the above portion, the observer can perceive the light L3 without being obstructed by the multilayer film 13. Therefore, the display body can display an original image to the observer OB.

As described above, the display 1A described with reference to fig. 1 can be manufactured by scanning the multilayer film 13 of the blank medium 1A0 described with reference to fig. 2 with laser light. This laser scanning can be completed in a very short time as compared with a process of transferring a hologram onto a blank medium in units of pixels. Therefore, according to the above-described technique, a display body for displaying an image of a structural color can be manufactured in a short time.

As is clear from the description heretofore, the manufacture of the display 1A requires a high-level and complicated optical design and high accuracy. Therefore, it is difficult to forge the display 1A.

Next, embodiment 2 of the present invention will be explained.

Fig. 6 is a sectional view schematically showing a display according to embodiment 2 of the present invention. Fig. 7 is a cross-sectional view schematically showing a blank medium that can be used for manufacturing the display shown in fig. 6.

The display 1B shown in fig. 6 and the blank medium 1B0 shown in fig. 7 are the same as the display 1A and the blank medium 1A0 according to embodiment 1, respectively, except for the points described below.

That is, the front surface layer 11, the reflective layer 12, and the back surface layer 14 are provided in the display 1B and the blank medium 1B0 instead of the front surface layers 11R, 11G, and 11B, the reflective layers 12R, 12G, and 12B, and the back surface layers 14R, 14G, and 14B.

The front surface layer 11 is provided on the back surface of the multilayer film 13. The front surface layer 11 is made of, for example, a transparent resin. The transparent resin may be a cured product of a thermosetting resin or a photocurable resin, a thermoplastic resin, an adhesive, or a pressure-sensitive adhesive. The front surface layer 11 may have a single-layer structure or a multi-layer structure.

The back surface of the front surface layer 11 includes a plurality of regions respectively constituted by the 1 st to 3 rd sub-regions. The above regions are regularly arranged on the back surface of the front surface layer 11. According to one example, the regions each have a shape extending in the X direction and are arranged in the Y direction.

The 1 st to 3 rd subregions are provided with the 1 st to 3 rd relief structures described in embodiment 1, respectively. According to one example, the 1 st to 3 rd sub-regions each have a shape extending in the X direction and are arranged in the Y direction.

The 1 st, 2 nd and 3 rd relief structures generate the 1 st, 2 nd and 3 rd diffraction gratings DGR, DGG and DGB, respectively, at the reflection surface which is the interface between the front surface layer 11 and the reflection layer 12. The 1 st, 2 nd, and 3 rd recessed portions RR, RG, and RB are provided at the positions of the 1 st, 2 nd, and 3 rd diffraction gratings DGR, DGG, and DGB, respectively.

The reflective layer 12 covers the back surface of the front surface layer 11. As the material of the reflective layer 12, for example, the material exemplified for the reflective layer 12B can be used.

The back layer 14 covers the back of the reflective layer 12. The back surface layer 14 is made of, for example, a transparent resin. The back layer 14 may be opaque. The resin constituting the back surface layer 14 may be a thermosetting resin, a cured product of a photocurable resin, a thermoplastic resin, an adhesive, or a pressure-sensitive adhesive.

1 or 2 of the front surface layer 11, the reflective layer 12 and the back surface layer 14 may be omitted. However, in the case where only the reflection layer 12 is omitted, materials having different refractive indices are used for the front surface layer 11 and the back surface layer 14.

This display 1B can be manufactured by the same method as that for the display 1A described above, except that the 1 st concave portion RR, the 2 nd concave portion RG, and the 3 rd concave portion RB are formed at the positions of the 1 st diffraction grating DGR, the 2 nd diffraction grating DGG, and the 3 rd diffraction grating DGB, respectively.

According to embodiment 2, the same effects as those of embodiment 1 can be obtained. In addition, when metal is used as the material of the reflective layer 12, the display 1B according to embodiment 2 can display a brighter image than the display 1A according to embodiment 1. In addition, the display 1B according to embodiment 2 can be easily formed to be thinner than the display 1A according to embodiment 1.

Next, an article with a tape display will be described.

Fig. 8 is a sectional view schematically showing an article with a display according to an embodiment of the present invention. The article 100AB with the display is, for example, a printed matter. The article 100AB with a display is a personal authentication medium such as a banknote, a securities, a certificate, a credit card, a passport, and an id (identification) card, or a package for packaging the contents.

The article with a display 100AB includes a display 1AB and an article 110 supporting the display.

When the article 110 is a printed matter, it includes a printed base material and a printed layer provided on the printed base material. The material of the printing substrate is, for example, plastic, metal, paper, or a composite thereof.

The display 1AB is the above-described display 1A or 1B. Display 1AB is supported by article 110 with its front surface adjacent the exterior of article 100AB with the display. The display body 1AB can be supported by the article 110 by being attached to the surface of the article 110 or embedded in the article 110, for example.

For example, the article 100AB with a display body may be manufactured by manufacturing the display body 1AB in advance and supporting it on the article 110. Alternatively, the article with a display 100AB may be manufactured by the following method.

Fig. 8 is a sectional view schematically showing an article with a blank medium according to an embodiment of the present invention.

The blank medium-attached article 100AB0 shown in fig. 8 has the same structure as the display-attached article 100AB, except that the 1 st recess RR, the 2 nd recess RG, and the 3 rd recess RB are not provided in the multilayer film 13. That is, the blank media-bearing article 100AB0 includes a blank media 1AB0 and an article 110 supporting the blank media. The blank medium 1AB0 is the blank medium 1a0 or 1B0 described above.

Such an article 100AB0 with a blank medium may be prepared in advance and a laser beam may be irradiated to the blank medium 1AB0, thereby producing an article 100AB with a display body.

Further, if the front surface of the laminate in which the 1 st recessed portion RR, the 2 nd recessed portion RG, and the 3 rd recessed portion RB are formed is exposed, the recessed portions may be deformed by friction or the like when the display 1A, 1B, or 1AB or the article with display 100AB is used. Therefore, it is preferable to provide a protective layer made of a transparent material on the front surface of the laminate.

The protective layer may cover only the front surface of the laminate, or may cover the front surface of the display body 1AB and the front surface of the article 110.

A thicker protective layer does not affect the interference of the multilayer film 13. On the other hand, a thin protective layer may affect interference of the multilayer film 13. That is, in the latter case, the protective film is used as a part of the multilayer film 13. Therefore, in this case, the multilayer film 13 is designed to exhibit the above-described optical characteristics in a state of including the protective layer.

Examples

Examples of the present invention are described below.

A display body having a similar configuration to the display body 1A described with reference to fig. 1 was manufactured.

Here, the multilayer film 13 is composed of 1 dielectric layer 13a and 1 dielectric layer 13 b. As the material of the dielectric layer 13a, a material having a refractive index of 1.98 was used, and its thickness was set to 700 nm. As the material of the dielectric layer 13b, a material having a refractive index of 1.28 was used, and its thickness was 650 nm.

The 1 st recess RR is formed so that the thickness of the 1 st portion reaches 600 nm. The 2 nd recess RG is formed so that the thickness of the 2 nd portion reaches 300 nm. Also, the 3 rd recess RB is formed such that the thickness of the 3 rd portion reaches 200 nm.

A protective layer is formed on the dielectric layer 13 a. As a material of the protective layer, a material having a refractive index of 2.5 is used, and the thickness thereof is set to be sufficiently large to not affect the interference of the multilayer film 13.

The 1 st blazed diffraction grating is formed to enable the spatial frequency of grating lines to reach 1150 lines/mm. The 2 nd blazed diffraction grating is formed such that the spatial frequency of the grating lines reaches 1320 lines/mm. The 3 rd blazed diffraction grating is formed to have the spatial frequency of the grating lines up to 1550 roots/mm.

Further, with respect to the multilayer film 13 having the above structure, a transmission spectrum in the case of illumination from the normal direction with white light is obtained by computer simulation. The results are shown in fig. 10 to 12.

Fig. 10 is a graph showing a transmission spectrum obtained by computer simulation for the 3 rd portion corresponding to the 3 rd recess RB of the multilayer film 13. Fig. 11 is a graph showing a transmission spectrum obtained by computer simulation for the 3 rd portion corresponding to the 2 nd recess RB of the multilayer film 13. Fig. 12 is a graph showing a transmission spectrum obtained by computer simulation for the 3 rd portion corresponding to the 1 st recess RB of the multilayer film 13.

Although not shown, the transmittance of the portion of the multilayer film 13 where no recess is provided is substantially constant over the entire visible region.

In contrast, in the transmission spectrum shown in fig. 10, the transmittance in the blue region is lower than the transmittance in the other wavelength regions in the visible region. That is, the intensity of the blue region of the light transmitted from the 3 rd portion is low, and the intensities of the green region and the red region are high. Thus, the transmission from part 3 appears yellow.

In the transmission spectrum shown in fig. 11, the transmittance in the green region is lower than the transmittance in the other wavelength regions in the visible region. That is, the intensity of the green range of the light transmitted from the 2 nd portion is low, and the intensities of the blue range and the red range are high. Therefore, the light transmitted from the 2 nd part looks magenta.

In the transmission spectrum shown in fig. 12, the transmittance in the red region is lower than the transmittance in the other wavelength regions in the visible region. That is, the intensity of the red range of the light transmitted from the 1 st portion is low, and the intensities of the blue range and the green range are high. Therefore, the light transmitted from the 1 st portion looks cyan.

On the other hand, when the illumination is performed from the normal direction by white light, the 1 st, 2 nd, and 3 rd blazed diffraction gratings emit strong primary diffracted lights of red, green, and blue, respectively, in the same direction inclined with respect to the normal direction. That is, the combination of the 1 st, 2 nd, and 3 rd blazed diffraction gratings has a substantially uniform reflectance over substantially the entire visible region, and functions as a reflection surface that reflects incident light at a reflection angle different from the incident angle.

Therefore, the display body can display a color image having a pattern corresponding to the arrangement of the 1 st concave portion RR, the 2 nd concave portion RG, and the 3 rd concave portion RB as a diffraction image.

In fact, when the display manufactured as described above was observed while being illuminated with white light, it was confirmed that the display could display a desired color image as a diffraction image.

In the above embodiment, a blazed diffraction grating is used, but the present invention is not limited to the blazed diffraction grating, and a holographic diffraction grating, a layered diffraction grating, or the like may be used.

Description of the reference numerals

1a … shows a volume, 1a0 … blank medium, 1AB … shows a volume, 1AB0 … blank medium, 1B … shows a volume, 1B0 … blank medium, 11 … front surface layer, 11B … front surface layer, 11G … front surface layer, 11R … front surface layer, 12 … reflective layer, 12B … reflective layer, 12G … reflective layer, 12R … reflective layer, 13 … multilayer film, 13a … dielectric layer, 13B … dielectric layer, 14 … back surface layer, 14B … back surface layer, 14G … back surface layer, 14R … back surface layer, 100AB … article with display volume, 100AB0 … article with blank medium, 110 … article, DG … 1 st reflective surface, DGB … rd 3 diffraction grating, DGG … nd 2 diffraction grating, R … st diffraction grating, L … light, L … light, LB … light source …, L …, LB … st diffraction grating …, L … st diffraction grating …, B … st diffraction grating …, observation objective lens …, REF … reflective surface, RG … nd recess 2, RR … st recess 1.