JP2012198481A - Image representation body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image representation body improving a design property of a hologram transfer body, having superior anticounterfeit and anti interpolation property, and capable of quickly and surely determining authenticity.SOLUTION: The image representation body comprises a diffraction grating forming layer 3 and a reflection layer 4, and is formed by selectively disposing a plurality of first elements and second elements in a boundary surface between the diffraction grating forming layer 3 and the reflection layer 4, where the first element includes a rugged structure of a diffraction grating or a hologram, and the second element includes no rugged structure of the diffraction grating or the hologram. An image gradation is formed by changing occupancy rates of the first element and the second element per area and a spectral reflectance in a visible light wavelength region of the reflection layer 4 of the first element and the second element.

Description

  This patent relates to an image representation body having an image and a hologram image at the same time by combining unit elements composed of two or more types of reflection layers and hologram forming layers having different reflection characteristics.

  OVD (Optical Variable) like a multilayer thin film that can change the color depending on the viewing angle by superimposing holograms, diffraction gratings, and thin films with different optical characteristics, which can express stereoscopic images and special decorative images using light interference. The use of Device is continuously increasing. It is still difficult to easily forge a fine image expression, and it is still representative of anti-counterfeiting technology.

  Holograms are very popular especially in fields that require security. As an example of use, it is difficult to counterfeit or falsify personal information written on a transferred object by transferring and pasting a transparent or translucent hologram transfer object to a document that has transferred personal information. It is.

  It is required to improve the design of the hologram transfer body. To that end, the hologram transfer body and multilayer film transfer body are transferred as pixels from multiple panels including several types of hologram transfer bodies and multilayer film transfer bodies, and custom holograms are transferred. An image forming method to be formed has been proposed (Patent Document 1).

  In addition, in order to enhance designability, a proposal has been made to combine with a black ribbon and express black in addition to the color expressed by diffracted light. However, even if black can be expressed, it cannot be said that the security is improved (Patent Document 2).

  In addition to black, proposals have been made to further enhance the design by coloring the diffraction grating forming layer using process ink. However, although the design property is improved by coloring the diffraction grating forming layer, it cannot always be said that the security property is improved by coloring. This is because it is not so difficult to produce a visual effect very similar to that when the hologram layer is colored without coloring the diffraction grating forming layer. For example, it is not so difficult to prepare an image in advance and form a diffraction grating in accordance with this image. By doing so, it is possible to have a very similar visual effect (Patent Document 3). .

JP 2005-538423 A JP 2006-301081 A JP 2005-234559 A

  The present invention is an invention made in view of the problems of the chromatic hologram transfer body, which can prevent separation of the image on the substrate and the hologram image forming portion, improve the design of the hologram transfer body, and improve security. The object is to create an image representation that is high in anti-counterfeiting and tamper-proof, and that can quickly and reliably determine authenticity.

  As means for solving the above-mentioned problems, the invention according to claim 1 is composed of a diffraction grating forming layer and a reflective layer, and a concavo-convex structure of the diffraction grating or hologram is formed at the interface between the diffraction grating formed layer and the reflective layer. An image display body formed by selectively arranging a plurality of first elements having a diffraction grating or a second element having no concavo-convex structure of a hologram, wherein the area per area of the first element and the second element An image expression body in which an image gradation in which an occupation ratio and a spectral reflectance in a visible light wavelength region of a reflection layer of a first element and a second element are changed is formed.

  According to a second aspect of the present invention, there is provided an image display body in which the spectral reflectance of the reflection layer in the first element and the second element and the first element and the second element is changed for each element. A diffraction grating or a hologram image formed by an element having a diffraction grating or a concavo-convex structure of a hologram, in which the product of the reflection layer having different diffraction efficiency and spectral reflectance is the same in a specific wavelength region, is displayed. The image representation body according to claim 1.

  Do not use ink as in printing and coating, but form images by combining multiple sheets such as colored grids, colored grids, transparent grids, transparent grids, etc., with pixels colored by the optical properties of the reflective layer As a result, it is possible to produce an image representation that cannot separate the image on the substrate and the hologram image forming portion, has very high anti-counterfeiting and tampering properties, and can quickly and reliably determine authenticity.

It is a cross-sectional conceptual diagram which shows the structure and transfer operation of a transfer sheet. Example of coloring / hologram images Decomposition coloring / hologram images, useless coloring grid images (ZnSe) Decomposing chromatic / hologram images, useful chromatic grid images (ZnSe) Decomposition coloring / hologram image, transparent grating useless image (ZnS) Decomposition coloring / hologram image, transparent grating useful image (ZnS) Data showing changes in refractive index and extinction coefficient depending on the wavelength of the ZnS thin film. Data showing changes in refractive index and extinction coefficient depending on the wavelength of the ZnSe thin film. It is a cross-sectional conceptual diagram of the diffraction grating model used for this invention. It is data which shows the change of the diffraction efficiency by the wavelength of ZnS and ZnSe.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. An example of an operation for transferring a hologram to a transfer target, which is the hologram image forming method of the present invention, will be described. FIG. 1 is a cross section of a transfer sheet, in which a peeling / protecting layer 2 is formed on a heat-resistant substrate layer 1, and a resin layer (hereinafter referred to as a diffraction grating forming layer 3) capable of forming a diffraction grating is formed thereon. A diffraction grating designed according to the purpose is formed on the diffraction grating forming layer 3. A reflection layer 4 is formed on the diffraction grating forming layer 3 to improve diffraction luminance.

  One of the reflective layer materials for transparent holograms is ZnS. This is because the reflection characteristic of ZnS is substantially constant over the entire visible range and exhibits a high reflection characteristic. The above two layers, the diffraction grating forming layer 3 and the reflective layer 4 are grouped together (hereinafter referred to as “hologram transfer body 6”) and transferred to the transfer body 7. In order to transfer the hologram transfer body 6 to the body 7 to be transferred, an adhesive layer 5 is further required.

The adhesive layer 5 may be applied to the hologram transfer body 6 or a separate adhesive layer sheet may be prepared. When the substrate layer 1, the peeling / protecting layer 2, and the hologram transfer body 6 are brought into contact with the transfer body 7 through the adhesive layer 5 and heat is applied, the hologram transfer body 6 is bonded to the transfer body 7 by the action of the adhesive layer 5. At the same time, the hologram transfer body 6 is peeled from the substrate layer 1 with the separation / protection layer 3 as a boundary, and the hologram transfer body 6 is transferred to the transfer body 7. The peeling / protecting layer 2 may have a separate configuration, but may have a single layer configuration.

  Instead of applying heat to the entire hologram transfer body 6 for this transfer, it is also possible to transfer a part of the transfer body as a unit element.

  Consider an image as shown in FIG. For simplicity, the coloring is one color. The vertical line areas 11 and 12 indicate coloring, the others are colorless 13 and 14, and the horizontal lines 12 and 14 indicate that they have a diffraction grating. In this figure, the “X” image is shown by the chromatic colors 11 and 12, and the “S” image is shown by the holograms 12 and 14 having the diffraction grating.

  In this example, four types of unit elements, ie, a unit element having both color and grid, a unit element having only a color, a unit element having only a grid, and a unit element having neither grid are combined to form a single layer structure.

  However, when a chromatic image colored in the “X” image is prepared and a diffraction grating is formed on the “S” image chromatic image so as to match it, a display body that is very visually similar to the case where the diffraction grating forming layer 3 is colored. Is obtained. Specifically, there is a method of separately preparing sheets on which diffraction gratings are arranged so that a chromatic image and an intended hologram can be obtained, and sticking them together precisely, which is not so difficult per se.

  Thus, the coloring of the diffraction grating forming layer 3 does not necessarily mean that the security is high. This is because the image on the substrate and the hologram image forming part can be separated.

  Similar to ZnS, ZnSe is a material that is transparent and has a high refractive index. FIG. 7 shows the refractive index and extinction coefficient of ZnS, and FIG. 8 shows the wavelength of the refractive index and extinction coefficient of ZnSe. The major difference in the spectral characteristics between ZnS and ZnSe is that ZnSe has high transmittance from the infrared to the red region, and the extinction coefficient rapidly increases in the region where the wavelength is shorter than that of green. The light that has passed through ZnSe appears red because the light in the green / blue region decays rapidly. Due to this property, when ZnSe is used for the reflective layer, the light intensity in the green / blue region of the light transmitted through the reflective layer and reflected at the interface between the reflective layer 4 and the diffraction grating forming layer 3 is significantly reduced. It becomes the body 6. When a material having such optical properties is used for the reflective layer, the properties of the diffraction grating with the reflective layer are basically determined by the product of the optical properties of the grating forming layer and the optical properties of the reflective layer material.

  9 is used when the diffraction grating model (grating depth is 120 nm, reflection layer thickness is 50 nm) shown in FIG. 9 using the spectral data of FIGS. 7 and 8 and the reflection layer material is ZnS or ZnSe. The intensity of the diffracted light with respect to the wavelength was calculated using the diffraction grating model. The wavelength of incident light is 450 nm to 650 nm. FIG. 10 shows the calculation result of the diffracted light intensity. As shown in FIG. 10, in the red region, the diffracted light intensity is almost the same for both reflective layer materials, but in the green region, the diffracted light intensity of ZnSe is extremely lower than that of ZnS. The light intensity increases.

  The hologram transfer body 6 using ZnS or ZnSe for the reflection layer 4 has the above characteristics. Therefore, in the previous example, the transfer body of the ZnSe reflection layer 4 is used in place of the chromatic hologram transfer body 6, and when an image is formed, an image can be displayed on the substrate with the color of ZnSe, and a hologram image can be displayed on the diffraction grating. However, unlike the previous example, the image of the hologram image differs depending on the color of the diffracted light.

When an image is formed with the color of ZnSe, the hologram image and the image on the substrate cannot be expressed separately as in the previous example. Therefore, the method of preparing each image separately and overlaying them cannot be applied.

  Next, an embodiment of the present invention will be described. In the present invention, the transfer bodies 12 and 14 having the reflection layer 4 and having the diffraction grating, the transfer bodies 11 and 13 having no diffraction grating, and the reflection layer 4 need two kinds of ZnS and ZnSe. Four types of transfer bodies are required. Hereinafter, the case where both the image and the hologram image, which are the simplest examples, represent the “X” image and the “S” image by using ZnS and ZnSe as the reflective layer material will be described.

  A transfer method will be described. Each of the transfer bodies of ZnSe reflective layer lattice 12, ZnSe reflective layer lattice 11, ZnS reflective layer lattice 14, and ZnS reflective layer lattice 13 is selectively unitized according to preset image information on the substrate. Placed in. The image information is converted into dedicated images for each of the four transfer bodies so that two images for image and hologram are formed. Specifically, taking the image information of FIG. 2 as an example, ZnSe reflective layer lattice 11, ZnSe reflective layer lattice 12, ZnS reflective layer lattice 13, ZnS reflective layer lattice 14, respectively, are shown in FIGS. Six images are assigned.

  These transfer bodies are transferred to the transfer body 7 in precise alignment. There is no particular specification for the order of printing. In this example, when the transfer is performed under the above-described conditions, a single-layer structure is formed. However, in order to produce various visual effects, the transfer bodies may be overlapped.

  When the unit elements of the four types of transfer members are properly arranged, as shown in FIG. 2, when viewed directly, an “X” image can be seen with the color of ZnSe, light is applied at a predetermined angle, and the diffracted light is observed. And "S" hologram image can be seen. However, as the hologram image, an intended image can be seen only in a predetermined wavelength range. For example, when the red image is set, the intended image cannot be seen in the green and blue regions. The hologram image in the green region is as shown in FIG. 5 and in the blue region as in FIG.

  This display body is very difficult to counterfeit because it cannot be established unless the unit elements of the two types of reflective layer materials are properly arranged. For example, when the image on the substrate and the hologram image are separately formed and pasted as in the previous example, the same image is displayed in the entire wavelength range. Since the color of the diffracted light changes when the viewing zone is changed, visual confirmation of the image for each color can be performed easily and instantaneously. Since the expression according to the present invention can accurately determine the authenticity in a very short time, the image expression becomes an item that is very practical and highly secure.

  In this example, ZnS and ZnSe are given as examples of changing the optical characteristics, but the method of changing the optical characteristics is not particularly limited. The method for forming the diffraction grating has been described by way of example of transfer, but is not limited thereto. Further, in this description, for the sake of simplicity, only an expression having one hologram is described, but the number of hologram images is not limited.

  As described above, a combination of sheets of chromatic grid with ZnSe12, chromatic grid without ZnSe11, transparent grid with ZnS14, and transparent grid without ZnS13 with optical properties as described above is extremely counterfeiting, tamper-resistant, and quick. Thus, it is possible to make an image representation that can reliably determine authenticity.

DESCRIPTION OF SYMBOLS 1 ... Substrate layer 2 ... Peeling / protection layer 3 ... Diffraction grating formation layer 4 ... Reflective layer 5 ... Adhesive layer 6 ... Hologram transfer body 7 ... Transferee 11 ..ZnSe without lattice
12 ... ZnSe with lattice
13 ... Lattice-free ZnS
14 ... ZnS with lattice

Claims (2)

  A first element having a diffraction grating or hologram uneven structure at the interface between the diffraction grating forming layer and the reflection layer, and a second element having no diffraction grating or hologram uneven structure at the interface between the diffraction grating forming layer and the reflection layer. An image display body formed by selectively arranging a plurality of elements, the occupation ratio per area of the first element and the second element, and in the visible light wavelength region of the reflection layer of the first element and the second element An image expression body in which an image gradation having a changed spectral reflectance is formed.   In the image display body in which the spectral reflectance of the reflective layer in the first element and the second element and the reflective layer in the first element and the second element is changed for each element, the reflective layers having different diffraction efficiency and spectral reflectance of the diffraction grating or hologram structure The image representation body according to claim 1, wherein a diffraction grating or a hologram image formed by an element having a diffraction grating or a concavo-convex structure of a hologram having the same reflectance product in a specific wavelength region is displayed.