JP2008083599A - Optical element and display body using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element which has structure of difficult forgery and has constitution of easy authenticity discrimination. <P>SOLUTION: The optical element 19 of this invention has a planar structure 11 where rugged structure patterns 11a, 11b capable of obtaining two or more kinds of different optical functions are formed on one surface and a dielectric layer 12 which is arranged at a surface side where the rugged structure patterns 11a, 11b of the structure 11 are formed, in which layer thickness is determined in advance, and which is made of one or more layers with an optical function. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is formed by disposing a dielectric layer on a fine structure having an optical function formed on an uneven surface such as a relief surface, and an optical element suitable mainly for security and its use. Related to the display body.

  Conventionally, for example, as disclosed in Patent Documents 1 to 9, in order to prevent forgery, a fine structure or color change that cannot be easily imitated is applied, or another optical function film is used as a determinator, and only in combination therewith. Various modes have been put into practical use with the advancement of technology, such as a configuration in which a certain optical phenomenon is observed, or a configuration in which a fixed pattern or the like can be read only by a dedicated reading device.

  Among them, a hologram and a diffraction grating image are given as one of the most utilized because of practical ease of operation. A hologram is produced by providing a fine concavo-convex pattern and a refractive index distribution by an optical photographing method such as two-beam interference. On the other hand, the diffraction grating image is produced using a pixel in which a diffraction grating is arranged in a minute area.

  Both the hologram and diffraction grating image are difficult to counterfeit, difficult to copy with a color copier, etc., and are excellent in design. Therefore, optical elements provided with holograms and diffraction gratings are widely used for credit cards, ID cards, various securities, certificates and the like. However, in actual operation, the authenticity of holograms and diffraction grating images is left to the human eye, so even if it is a microscopically fake product, all people can accurately and accurately authenticate with the naked eye. It is not easy to make a false determination.

  On the other hand, for the reason that the authenticity can be easily determined visually and it is difficult to make a copy with a color copier, a laminate is mainly proposed by laminating a plurality of layers having different refractive indexes.

In this case, light of a specific wavelength is strongly reflected, and the wavelength changes depending on the reflection angle, so that a phenomenon that the color changes depending on the viewing angle (observation angle) can be observed. Thus, an optical element provided with a laminate that visually changes color is also referred to as a goniochromatic element. By observing the presence or absence of this color change, authenticity can be determined relatively easily, and of course copying by a color copier is impossible.
Japanese Patent No. 2797944 Japanese Patent No. 3139255 Japanese Patent No. 3329234 Japanese Patent No. 3395322 Japanese Patent No. 3409612 Japanese Patent No. 3345840 Japanese Patent No. 3470411 Japanese Patent No. 3480336 Japanese Patent No. 3536413 JP 2002-333854 A

  However, even if an optical element provided with such a laminated body, that is, a goniochromatic element, is counterfeited by a laminated body that shows a similar color change in some way, all people are able to accurately and accurately authenticate. There is a problem that it is difficult to make a false determination.

  The present invention has been made in view of such circumstances, and provides an optical element having a structure that is difficult to forge and having a configuration that allows easy determination of authenticity on the spot, and a display body using the optical element. For the purpose.

  In order to achieve the above object, the present invention takes the following measures.

  That is, the optical element of the invention of claim 1 has a planar structure in which two or more different optical functions are obtained on one surface, and a concavo-convex structure pattern of the structure. And a dielectric layer composed of one layer or a plurality of layers having a predetermined layer thickness and an optical function.

  According to a second aspect of the present invention, in the optical element of the first aspect of the invention, the concavo-convex structure pattern includes a first structure pattern that provides a light diffraction function as an optical function, and a second structure that provides a light scattering function as an optical function. Including at least one of the structural pattern.

  According to a third aspect of the present invention, in the optical element of the second aspect of the invention, the first structure pattern is a diffraction grating, and when irradiated with white light, a range centered on an angle of orientation defined by the diffraction grating , White diffracted light is emitted according to the intensity distribution defined by the diffraction grating.

  According to a fourth aspect of the present invention, in the optical element of the second or third aspect of the present invention, the second structure pattern is a light scattering pattern in which a light scatterer including a light scattering element is arranged, and the light scattering element A predetermined light scattering function is obtained by changing the shape of the light scattering element and the density of the light scattering elements in the light scattering body.

  According to a fifth aspect of the present invention, in the optical element according to any one of the first to fourth aspects, the dielectric layer is composed of a plurality of layers, and each layer is composed of a ceramic material having a different refractive index.

  According to a sixth aspect of the present invention, in the optical element according to any one of the first to fourth aspects, the dielectric layer includes a layer having a refractive index higher than a predetermined value and a predetermined value. It consists of a plurality of layers including a layer having a low refractive index.

  According to a seventh aspect of the present invention, in the optical element according to any one of the first to fourth aspects, the dielectric layer has a higher refractive index than the adjacent layer and a lower refractive index than the adjacent layer. It consists of a plurality of layers in which layers having a ratio are alternately stacked.

  According to an eighth aspect of the present invention, in the optical element of the first aspect of the present invention, a light absorption layer having a light absorption function, a light scattering layer having a light scattering function, and a light reflection are provided on the side of the dielectric layer that is not the structure side. An optical functional layer including at least one of the light reflecting layers having a function is disposed.

  According to a ninth aspect of the invention, in the optical element of the eighth aspect of the invention, any one of the layers included in the optical functional layer is partially provided according to a predetermined pattern.

  A tenth aspect of the present invention is the optical element of the eighth or ninth aspect, wherein any one of the layers included in the optical functional layer is a cross section along the cross sectional shape of the layer adjacent to the structure side. It has a shape.

  According to an eleventh aspect of the present invention, in the optical element according to any one of the first to tenth aspects, a light transmissive metal layer is disposed on a surface side of the dielectric layer that is not the structure side.

  According to a twelfth aspect of the present invention, in the optical element according to any one of the first to eleventh aspects, the surface of the structure on which the concave / convex structure pattern is not formed is provided on the surface side of the scratch resistance and antifouling property. A protective layer having at least one of them is disposed.

  A thirteenth aspect of the present invention is a display body characterized in that the optical element according to any one of the first to twelfth aspects of the present invention is arranged on a base made of card or paper.

  According to a fourteenth aspect of the present invention, in the display body according to the thirteenth aspect, a printed layer is disposed between the base material and the optical element.

  According to a fifteenth aspect of the present invention, in the display body according to the thirteenth or fourteenth aspect of the present invention, the substrate has light transmittance.

  According to the present invention, it is possible to realize an optical element having a structure that is difficult to forge and having a configuration that allows easy determination of authenticity on the spot, and a display body using the optical element.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a conceptual diagram showing a cross-sectional configuration example of an optical element (goniochromatic element) according to a first embodiment of the present invention.

  That is, the optical element shown in FIG. 1 has an optical structure in which concave and convex structure patterns 11a and 11b that can obtain two or more different optical functions, such as a diffraction structure having a light diffraction function and a scattering structure having a light scattering function, are formed. The goniochromatic element 10 is provided with a dielectric layer 12 composed of one layer or a plurality of layers having a layer thickness controlled in advance and having an optical function on the uneven surface side (non-observer 2 side) of the body 11.

  In the present embodiment, the observer 2 observes the goniochromatic element 10 in the arrangement state as shown in FIG. 1 unless otherwise specified.

  Here, the diffractive structure is a structure capable of diffracting and interfering with light by repeating fine physical irregularities in the order of the wavelength of light, or by repeating portions having different refractive indexes. Holograms and diffraction gratings are well known. In particular, a diffraction grating has a high degree of freedom in design and can provide various optical functions because a necessary structure can be calculated backward based on a theory from a desired image or optical characteristics.

  In ordinary diffraction grating images, a plurality of types of diffraction gratings are arranged so that a color image can be obtained by diffracted light at a fixed angle. However, depending on the conditions of the diffraction gratings to be arranged, an angle with a certain direction It is also possible to obtain white diffracted light having a certain predetermined intensity distribution in a certain range centered on.

  This principle will be described with reference to FIGS. FIG. 2 is a partial plan view showing a configuration example of the goniochromatic element 10 for obtaining the above-described white diffracted light. The goniochromatic element 10 includes pixels G each including a diffraction grating K, and each pixel G includes a different diffraction grating K. Hereinafter, the effects of the structure of FIG. 2 will be described in detail with reference to FIGS.

  As shown in FIGS. 3A and 3B, the diffraction grating K generally diffracts incident light I incident at a certain angle from the light source 1 and performs wavelength spectroscopy over a certain angle. At this time, the angle region φ of the diffracted light D subjected to wavelength spectroscopy varies depending on the spatial frequency of the diffraction grating K. Therefore, as shown in FIG. The diffracted light D having different wavelengths with φ is superimposed, and white diffracted light is obtained.

  Further, the orientation of the diffracted light D depends on the ridge line direction of the diffraction grating K as shown in the plan views of FIGS. 4A, 4B, and 4C, and FIG. In the structure having the arcuate ridgeline R as shown in FIG. 5, the diffracted light D having a certain spread angle θ corresponding to the ridgeline R can be obtained.

  As described above, as shown in the example of FIG. 2, in a structure in which a plurality of pixels G each having a different spatial frequency and composed of an arcuate ridge line R are arranged, a constant spread angle in a constant angle region φ. White diffracted light D having θ is obtained. Furthermore, in consideration of the fact that the angle of the incident light I is not constant in the environment of the normal observer 2, the above-described superposition of the angle region φ of the diffracted light D is also performed within the single pixel G in FIG. Therefore, the white diffracted light D can be obtained in a wider range.

  In addition to the color image described above, the goniochromatic element 10 according to the present embodiment has a structure capable of obtaining white diffracted light having a certain predetermined intensity distribution in a certain range as described above. By providing, more various optical functions can be realized. In particular, it is possible to obtain a variable angle contrast with the portion 11c having no uneven pattern and the portions 11a and 11b having a scattering structure. The variable angle contrast refers to the contrast of an image observed when the viewing angle of the observer 2 is changed with respect to the observation target (broadly defined contrast including luminance, S / N, and color difference). In the present invention, the present invention is not limited to these, and an uneven structure having any light diffraction function can be applied.

  The scattering structure here refers to a surface or interface structure in which light is scattered by the uneven structure. This concavo-convex structure is formed by physically colliding particles with the surface like sand blasting or wet blasting, applying a coating liquid to which particles are added, drawing a concavo-convex shape by lithography, or in advance It can be obtained by duplicating a surface having an uneven structure. In particular, when it is intended to stably obtain a certain uneven structure, it can be said that lithography capable of providing preset unevenness has a high degree of design freedom and is superior. For example, as disclosed in Japanese Patent Application Laid-Open No. 2002-333854 (Patent Document 10), in a light scattering pattern in which a light scatterer composed of a light scattering element is arranged, the shape of the light scattering element, The light scattering property can be appropriately set by changing the density of the light scattering element.

  Moreover, light scattering can also be caused anisotropically by making the concave-convex shape into a so-called hairline shape in which concave portions and convex portions extend only in one direction. Note that the present embodiment is not limited to the above, and any structure having a light scattering function can be applied.

  The optical structure 11 can be obtained, for example, by transferring and forming a concavo-convex structure on a substrate using a master stamper in which a concavo-convex pattern opposite to the concavo-convex structure patterns 11a and 11b is formed in advance. Specifically, a method of embossing by pressing the stamper against the base material, a method of replicating the stamper pattern on the base material through an ionizing ray curable resin, or the like can be used. Of course, the method is not limited to the above method as long as each structure can be formed.

  The above-described base material is not particularly limited as long as it is a light-transmitting base material. Examples thereof include polyethylene terephthalate, polyvinyl chloride, polyester, polycarbonate, polymethyl methacrylate, polystyrene, and triacetyl cellulose films. Can be used.

  The dielectric layer 12 has a goniochromatic function in which the color changes depending on the viewing angle of the observer 2. In order to realize this, it can be obtained by laminating a plurality of ceramic materials having different refractive indexes. Here, a material having a refractive index greater than 1.5 with respect to visible light is defined as a high refractive material, and a material having a refractive index of 1.5 or less is defined as a low refractive material. As a preferred example, a dielectric layer 12 in which layers 21 and 23 made of a high refractive index material and layers 22 made of a low refractive material are alternately laminated with a predetermined thickness as in the goniochromatic element 20 shown in FIG. It is done.

As the highly refractive material, for example, ZnS, TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , ZrO ₂ , CeO ₂ , HfO ₂ , Y ₂ O ₃ , PbF ₂ or the like can be used. Of course, any material other than those shown here can be used as long as it is light transmissive and has a high refractive index with respect to visible light.

As the low refractive material can be used, for example _{Na 3 AlF 6, Na 5 Al} 3 F 14, AlF 3, MgF 2, SiO 2, BaF2 , and the like. Needless to say, any material other than the materials shown here can be used as long as it is light transmissive and has a low refractive index with respect to visible light.

  At least one kind is selected from each of these high-refractive materials and low-refractive materials, and a layer made of a high-refractive material and a low-refractive material are alternately laminated on the optical structure 11 with a predetermined thickness. Thus, a material having a high transmittance or reflectance with respect to visible light having a specific wavelength can be obtained.

  Any film forming method can be used for the dielectric layer 12 as long as the layer thickness can be controlled. In the case of a dry method, a physical vapor deposition method such as a vacuum deposition method or a sputtering method or a chemical vapor deposition method such as a CVD method is used. In the case of a wet method, die coating, gravure coating, micro gravure coating, roll coating, dip coating or the like is used. However, in the case of a wet method, a polymer, oligomer, or monomers containing fluorine atoms as a coating liquid for a low refractive material, or a mixture of the above-mentioned fine particles of a low refractive material in a polymer, oligomer, or monomer, or an inorganic substance A sol such as an alkoxide can be used. As the coating liquid of the high refractive material, a mixture of the above-described fine particles of the high refractive material in a polymer, oligomer, or monomer, or a sol of metal alkoxide such as zinc, titanium, niobium, or zirconium can be used.

  Alternatively, the stamper may be embossed by pressing it onto a film or the like on which layers having different refractive indexes are previously laminated.

  With the configuration of these dielectric layers 12, in the goniochromatic element according to the present embodiment, the specific wavelength component of the reflected light and transmitted light can be selectively strengthened with respect to the incident light, and an arbitrary color is exhibited. It becomes possible. Of course, since this effect also depends on the incident angle and the viewing angle, a unique color change can be obtained by changing the viewing angle.

  Furthermore, in the present embodiment, the specific wavelength component is strong due to the diffraction structure and the light scattering structure and is diffracted or scattered, so that a completely unique appearance can be realized. It becomes possible to make a visual determination with certainty. Further, since the dielectric layer 12 is formed in a structure that is difficult to forge / imitate, such as a diffraction structure and a light scattering structure, it is difficult to make a similar product.

  In addition, as shown in FIG. 6, the goniochromatic element 30 in which the light-transmitting metal layer 31 is provided on the surface of the dielectric layer 12 is different from the color change depending on the viewing angle only by the dielectric layer 12. Color change can be given. Alternatively, as shown in FIG. 7, the above-described effect can be obtained by using a goniochromatic element 40 in which the metal layer 31 is disposed at the interface between the optical structure 11 and the dielectric layer 12. The metal layer 31 is not particularly limited as long as it is a light transmissive metal, but generally aluminum, chromium, or oxides thereof are used. At this time, it is necessary to appropriately set the layer thickness for each material so that an appropriate light transmittance can be obtained.

  FIG. 8 is a conceptual diagram illustrating a cross-sectional configuration example of a goniochromatic element 50 in which a protective layer 51 is provided on the front surface of the optical structure 11, that is, the surface where the uneven structure patterns 11 a and 11 b are not formed. The protective layer 51 alone has the effect of preventing forgery and imitation of the concave-convex structure patterns 11a and 11b of the optical structure 11. However, the protective layer 51 has an anti-scratch function and / or antifouling function, thereby providing the goniochromatic element 50. The effect of preventing scratches and / or soiling during practical use is obtained.

  FIG. 9 is a conceptual diagram illustrating a cross-sectional configuration example of a display body 60 in which a goniochromatic element 50 is disposed on a base material 63 such as a card or paper. The base material 63 is not particularly limited. For example, the goniochromatic element 50 can be disposed by bonding with a bonding layer 62 made of an adhesive or an adhesive.

  Furthermore, as shown in FIG. 10, the display body 70 provided with the higher forgery prevention effect is obtained by arrange | positioning the printing layer 71 on the base material 63. FIG. In the non-printed portion 71a, the light transmission component of the goniochromatic element 50 is reflected and scattered by the base material 63, whereas in the printed portion 71b, the above-described light transmission component is constant in the print layer 71. Only components that are absorbed in quantity and not absorbed will be reflected and scattered. By combining this effect with the light wavelength selection effect of the dielectric layer 12 described above, it is possible to realize a display body 70 that exhibits different colors in the printed portion 71b and the non-printed portion 71a. Of course, since this effect also depends on the angle and viewing angle of incident light, it is possible to obtain partially different color changes by changing the viewing angle. Furthermore, because the specific wavelength component is strongly diffracted or scattered by the diffraction structure and light scattering structure, it is possible to realize a completely unique appearance, and the visual judgment can be performed easily and reliably when determining authenticity. Can be done. Further, this display body 70 uses a goniochromatic element 50 in which a dielectric layer 12 is further arranged on an optical structure 11 that is difficult to forge / imitate, such as a diffractive structure and a light scattering structure. Making it even more difficult.

  As described above, according to the present embodiment, the optical structure 11 having the concavo-convex structure patterns 11a and 11b, which are fine structures that are difficult to forge, and the dielectric layer 12 having a layer structure, are visually observed. It is possible to provide a goniochromatic element that can easily make sure authenticity by a simple method such as observation. In particular, in addition to the visual effects of conventional holograms and diffraction gratings and / or light scattering patterns, the color change depending on the viewing angle can be made remarkably and peculiar. Can be realized.

  In addition, by providing the goniochromatic element with a protective layer 51 having scratch resistance and antifouling properties, it is possible not only to prevent forgery and imitation of the uneven structure patterns 11a and 11b, but also to be resistant to scratches and dirt. This makes it possible to obtain more practical functions.

  Further, by disposing a base material for this goniochromatic element, it becomes possible to realize a display body having the above-mentioned high anti-counterfeiting effect and design properties, and further, between the goniochromatic element and the base material. By providing the printing layer, it becomes possible to further enhance the effect of preventing forgery of the display body and the design.

(Second Embodiment)
The second embodiment of the present invention is a modification of the first embodiment. Therefore, here, the same portions are denoted by the same reference numerals to avoid redundant description, and different points will be described.

  FIG. 11 is a conceptual diagram showing a cross-sectional configuration example of an optical element (goniochromatic element) according to the second embodiment of the present invention.

  That is, the optical element shown in FIG. 11 has an optical structure in which concave and convex structure patterns 11a and 11b that can obtain two or more different optical functions such as a diffraction structure having a light diffraction function and a scattering structure having a light scattering function are formed. On the uneven surface side (non-observer 2 side) of the body 11, a dielectric layer 12 composed of one or more layers having an optical function is provided in advance, and an auxiliary layer 13 is further provided on the back surface thereof. This is a goniochromatic element 80. In the present embodiment, the observer 2 side of the goniochromatic element 80 is referred to as the front surface, and the opposite side is referred to as the back surface.

  The auxiliary layer 13 may be any one of a light absorption layer having a light absorption function, a light scattering layer having a light scattering function, and a light reflection layer having a light reflection function, or two or more different layers. it can. First, each effect when the light absorption layer, the light scattering layer, and the light reflection layer are combined with the dielectric layer 12 will be described.

  When a light absorption layer is used as the auxiliary layer 13, the light transmission component in the dielectric layer 12 is absorbed by the light absorption layer, so that only the reflected light component in the dielectric layer 12 is observed from the front surface. As a result, the reflected light component at the interface between the dielectric layer 12 and the air layer in the absence of the light absorbing layer is also absorbed, so that reflected light with higher wavelength selectivity can be obtained. Thereby, the inherent color change when the viewing angle is changed is more clearly observed.

  Next, when a light scattering layer is used as the auxiliary layer 13, the light transmission component in the dielectric layer 12 is scattered by the light scattering layer, so that in addition to the reflected light component in the dielectric layer 12, reflection is performed. Scattered light is observed. Therefore, if the observation angle is not particularly selected, the color of the reflected and scattered light is observed. However, when the specularly reflected light from the light source 1 is observed, the reflected light component on the dielectric layer 12 is observed. It can be a goniochromatic element 80 in which different colors are observed. Furthermore, when this light scattering layer is a light-transmitting light scattering layer, the goniochromatic element 80 having different effects on both sides so that the same color as the reflected scattered light can be observed from the back side. You can also.

  Further, when a light reflection layer is used as the auxiliary layer 13, the light transmission component in the dielectric layer 12 is reflected by the light reflection layer, so that the reflected light in addition to the reflection light component in the dielectric layer 12 is reflected. Will be observed. When the reflected light is not scattered, the coloration due to the dielectric layer 12 and the color change due to the viewing angle are not observed from the front surface. However, as described above, when the concavo-convex structure patterns 11a and 11b are provided in the optical structure 11, since the portion is scattered by the light reflecting layer, the above-described light scattering layer is provided from the front surface. The same effect can be obtained. Therefore, it is possible to obtain different coloration and a change in the viewing angle between the portion with the concavo-convex structure patterns 11a and 11b and the portion 11c without it.

  FIG. 12 shows an example of a goniochromatic element 90 in which the auxiliary layer 13 is partially provided according to a predetermined pattern. In the portion N where the auxiliary layer 13 is not present, the reflected light component on the dielectric layer 12 is observed from the front surface and the transmitted light component is observed from the rear surface. On the other hand, in each case where the auxiliary layer 13 is formed, different specific optical effects can be obtained by the combination with the dielectric layer 12 as described above.

  In FIG. 13, the auxiliary layer 13 is composed of two layers, a light absorption layer 41 and a light reflection layer 42, and only the light absorption layer 41 adjacent to the dielectric layer 12 is formed in a pattern as in FIG. An example of the goniochromatic element 100 is shown. In this case, in the portion N where the light absorption layer 41 is not present, the optical effect of the combination of the dielectric layer 12 and the light reflection layer 42 as described above is obtained, and in the portion where the light absorption layer 41 is formed, the dielectric as described above is performed. The optical effect by the combination of the body layer 12 and the light absorption layer 41 is each obtained.

  As described above, by forming any of the layers constituting the auxiliary layer 13 in a pattern, it is possible to realize a goniochromatic element that can simultaneously obtain different optical effects. Of course, the configuration of the auxiliary layer 13 is not limited to the example of FIGS. 12 and 13, and can be composed of any combination of a light absorption layer, a light scattering layer, and a light reflection layer, and according to each combination, Different optical effects can be obtained.

  FIG. 14 shows an example in which the auxiliary layer 13 is formed on the back surface of the dielectric layer 12 along the uneven surface of the optical structure 11. In this case, the uneven surface of the optical structure 11 can also be obtained on the back side of the auxiliary layer 13.

  Further, in FIG. 15, the goniochromatic element 120 in which the auxiliary layer 13 is partially provided according to a predetermined pattern and is formed on the back surface of the dielectric layer 12 along the uneven surface of the optical structure 11. An example is shown. As shown in FIG. 15, by forming the auxiliary layer 13 in a pattern and along the uneven surface of the optical structure 11, the portion N without the auxiliary layer 13 is formed on the dielectric layer 12. The goniochromatic element 120 having a wide variety of optical effects can be obtained so that the reflected light component is observed from the front surface and the transmitted light component is observed from the rear surface.

  For this explanation, a more specific example is shown in FIG. In FIG. 16, the light-absorbing layer 41 formed in a pattern so as to smooth the uneven surface on the back surface of the dielectric layer 12 having a shape along the uneven structure of the optical structure 11 is formed into the shape. An example of a goniochromatic element 130 provided with a light reflecting layer 42 having a shape along the shape is shown. In this case, in the portion N where the light absorption layer 41 is not present, the combined effect of <uneven structure of the optical structure 11 + dielectric layer 12 + light reflection layer 42> is obtained from the front, but in the portion where the light absorption layer 41 is present. The back surface is simply a flat reflecting surface.

  On the other hand, in the portion where the light absorption layer 41 is formed, the effect of <uneven structure of the optical structure 11 + dielectric layer 12 + light absorption layer 41> is obtained, and from the back, the uneven structure of the optical structure 11 is obtained. The light reflection layer 42 is added, and a visual effect derived from the uneven structure is obtained.

  That is, two different optical effects can be obtained on the front surface, and two different optical effects can be obtained on the rear surface. Of course, the configuration of the auxiliary layer 13 is not limited to this example, and any combination of a light absorption layer, a light scattering layer, and a light reflection layer can be used, and different optical effects can be obtained in each combination. Can do.

In the present embodiment, the light absorption layer 41 can be formed from a coloring layer formed of a dye or a pigment, an inorganic oxide or metal oxide layer having absorption in the visible light region, or a light-transmitting metal layer. . The colored layer is not particularly limited, but can be provided by a transparent ink containing a dye or a pigment, which is used for normal printing, for example. The metal oxide layer refers to a metal oxide that transmits almost no light over the entire visible light region, such as Cr ₂ O ₃ or SiO, but leaves some gloss, and has a metallic luster. Different viewing angle effects can be imparted. Further, the light transmissive metal layer 31 is not particularly limited as long as it is a metal exhibiting light transmissive properties, but generally aluminum, chromium, or an oxide thereof is used. At this time, it is necessary to appropriately set the film thickness for each material so that an appropriate light transmittance can be obtained.

  In the present embodiment, the light scattering layer is not particularly limited, and any material having a property of scattering light in the visible light region can be applied. Of course, here, for example, scattering on a surface having a certain surface roughness is also included.

  In the present embodiment, the light reflecting layer 42 is not particularly limited as long as it has a constant light reflectance in the visible light region, but from the viewpoint of reflectance, chromium, aluminum, gold, It is desirable to be formed from aluminum bronze or brass, or a metal capable of obtaining a reflectance equivalent to these.

  As described above, in the goniochromatic element according to the present embodiment, the dielectric layer 12 is formed in a structure that is difficult to counterfeit such as a diffraction structure and a light scattering structure, and the auxiliary layer 13 is formed in various forms. By providing, it becomes possible to further complicate the entire structure and to give an optically unique appearance. That is, it is possible to provide a goniochromatic element that is difficult to make a similar product, has excellent design properties, and is easy to determine authenticity.

  FIG. 17 is a conceptual diagram illustrating a cross-sectional configuration example of a goniochromatic element 140 in which a protective layer 81 is provided on the front surface of the optical structure 11. The protective layer 81 alone exhibits the effect of preventing forgery and imitation of the uneven structure of the optical structure 11, but further has a scratch resistance function and / or an antifouling function, so that the goniochromatic element 140 is put into practical use. The effect of preventing scratches and / or soiling can be obtained.

  FIG. 18 shows an example of a display body 150 in which a goniochromatic element 140 as shown in FIG. 17 is arranged on a base material 91 such as a card or paper. The substrate 91 is not particularly limited, and any solid can be applied as long as it can be arranged.

  In addition, as described above, if a display body in which a light-transmissive material is disposed as the base material 91 with respect to a goniochromatic element that exhibits different optical effects on the front surface and the back surface, the front surface and the back surface are different. A display body having an optical effect can be realized.

  Note that the display body 150 shown in FIG. 18 only relates to the configuration, and for example, the optical structure 11 and the dielectric are formed on a base material provided with a layer having a configuration equivalent to the auxiliary layer described above. The case where the element provided with the body layer 12 as an optical thin film is also included.

  As described above, according to the goniochromatic element according to the present embodiment, it has a fine structure and a layer structure that are difficult to counterfeit, and an auxiliary layer is provided on the back surface thereof, thereby allowing a simple method such as visual observation. Thus, reliable authenticity determination can be easily performed.

  In particular, by providing an auxiliary layer, in addition to the visual effects of conventional holograms and diffraction gratings and / or light scattering patterns, significant and specific color changes depending on the viewing angle by combining with a dielectric layer can be obtained, or the same Different colors and color changes can be obtained in the plane, or different aspects of the optical effect can be obtained on both sides.

  Further, in the goniochromatic element according to the present embodiment, by providing a protective layer having scratch resistance and antifouling on the front surface thereof, not only counterfeiting or imitation of the fine structure but also resistance to scratches and dirt. It is possible to obtain a more practical function.

  Furthermore, by disposing a base material on the goniochromatic element according to the present embodiment, it is possible to realize a counterfeiting / imitation display body having high anti-counterfeiting effects and design properties.

  The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element which concerns on 1st Embodiment. The partial top view which shows the structural example of the goniochromatic element for obtaining white diffracted light. The figure for demonstrating the principle which obtains white diffracted light with a goniochromatic element. The figure for demonstrating the principle from which the diffracted light with fixed divergence angle (theta) is obtained with the diffraction grating structure which has an arc-shaped ridgeline. The conceptual diagram which shows the cross-sectional structural example of a goniochromatic element provided with the dielectric material layer which laminates | stacks alternately a high refractive index material and a low refractive index material. The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element which provided the transparent metal layer on the surface of the dielectric material layer. The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element which has arrange | positioned the metal layer in the interface of an optical structure and a dielectric material layer. The conceptual diagram which shows the cross-sectional structural example of a goniochromatic element which provides a protective layer in the front surface of an optical structure. The conceptual diagram which shows the cross-sectional structural example of the display body formed by arrange | positioning a goniochromatic element on a base material. The conceptual diagram which shows the cross-sectional structural example of the display body provided with the higher forgery prevention effect by arrange | positioning a printing layer on a base material. The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element which concerns on 2nd Embodiment. The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element in which the auxiliary | assistant layer is partially provided according to the predetermined pattern. The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element in which the auxiliary | assistant layer was comprised from the light absorption layer and the light reflection layer, and only the light absorption layer adjacent to the dielectric material layer was formed in pattern shape. The conceptual diagram which shows the cross-sectional structural example of a goniochromatic element formed by forming an auxiliary layer in the back surface of a dielectric material layer along the uneven surface of an optical structure. The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element in which the auxiliary | assistant layer was partially provided according to the predetermined pattern, and was formed in the back surface of the dielectric material layer along the uneven | corrugated surface of an optical structure. The conceptual diagram which shows another cross-sectional structural example of the goniochromatic element in which the auxiliary layer was partially provided according to the predetermined pattern, and was formed in the back surface of the dielectric layer along the uneven surface of an optical structure. The conceptual diagram which shows the cross-sectional structural example of the goniochromatic element which provided the protective layer in the front surface of the optical structure. The conceptual diagram which shows the cross-sectional structural example of the display body formed by arrange | positioning the goniochromatic element shown in FIG. 17 on a base material.

Explanation of symbols

  D: Diffracted light, G: Pixel, I: Incident light, K: Diffraction grating, N: Part without auxiliary layer, R: Ridge line, φ: Constant angle region, θ: Constant spread angle 10, 20, 30 , 40, 50, 80, 90, 100, 110, 120, 130, 140 ... goniochromatic elements, 1 ... light source, 2 ... observer, 11 ... optical structure, 11a. 11b ... Uneven structure pattern, 11c ... Unpatterned part, 12 ... Dielectric layer, 13 ... Auxiliary layer, 21 ... High refractive index material layer, 22 ... Low refractive index material layer, 23 ... High refractive index material layer, 31 ... Metal layer 41 ... Light absorption layer 42 ... Light reflection layer 51 ... Protective layer 60, 70, 150 ... Display body 62 ... Joint layer 63 ... Base material 71 ... Print layer 71a ... No print area 71b: Printed portion, 81: protective layer, 91: base material

Claims (15)

A planar structure in which a concavo-convex structure pattern capable of obtaining two or more different optical functions is formed on one surface;
An optical element comprising a dielectric layer composed of one or a plurality of layers which is disposed on a surface side of the structure on which the concavo-convex structure pattern is formed, has a predetermined layer thickness, and has an optical function. .   The concavo-convex structure pattern includes at least one of a first structure pattern capable of obtaining a light diffraction function as an optical function and a second structure pattern capable of obtaining a light scattering function as an optical function. The optical element according to claim 1.   The first structure pattern is formed of a diffraction grating, and when irradiated with white light, white diffracted light is emitted in accordance with an intensity distribution defined by the diffraction grating in a range centered on an azimuth angle defined by the diffraction grating. The optical element according to claim 2, wherein   The second structure pattern is a light scattering pattern in which a light scatterer composed of light scattering elements is arranged, and the shape of the light scattering element and the density of the light scattering elements in the light scatterer are changed in advance. 4. The optical element according to claim 2, wherein a predetermined light scattering function is obtained.   5. The optical element according to claim 1, wherein the dielectric layer includes a plurality of layers, and each layer includes a ceramic material having a different refractive index.   5. The dielectric layer includes a plurality of layers including a layer having a refractive index higher than a predetermined value and a layer having a refractive index lower than the predetermined value. The optical element according to any one of the above.   The dielectric layer includes a plurality of layers in which layers having a higher refractive index than adjacent layers and layers having a lower refractive index than adjacent layers are alternately stacked. The optical element according to any one of 4. The optical element according to claim 1,
Optical including at least one of a light absorption layer having a light absorption function, a light scattering layer having a light scattering function, and a light reflection layer having a light reflection function on a surface side of the dielectric layer that is not the structure side An optical element in which a functional layer is arranged.   The optical element according to claim 8, wherein any one of the layers included in the optical functional layer is partially provided according to a predetermined pattern.   10. The optical according to claim 8, wherein any one of the layers included in the optical functional layer has a cross-sectional shape along a cross-sectional shape of a layer adjacent to the structure side. element. The optical element according to any one of claims 1 to 10,
An optical element, wherein a light transmissive metal layer is disposed on a surface side of the dielectric layer that is not the structure side. The optical element according to any one of claims 1 to 11,
An optical element, wherein a protective layer having at least one of scratch resistance and antifouling property is disposed on a surface side of the structure on which the uneven structure pattern is not formed.   A display body comprising the optical element according to any one of claims 1 to 12 arranged on a substrate made of a card or paper.   The display body according to claim 13, wherein a printed layer is disposed between the base material and the optical element.   The display body according to claim 13 or 14, wherein the base material has optical transparency.

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