JP2015123593A - Image display device, method for manufacturing image display device, and transfer ribbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device that facilitates visual determination of authenticity of an image, and a method for manufacturing the image display device, and a transfer ribbon.SOLUTION: The image display device includes: a transparent part 44 (transparent layer) containing a transparent resin and a heat-sensitive colorant that irreversibly changes colors at a color-changing temperature or higher; and a plurality of image cells 25 including a first image cell and a second image cell and covered with the transparent part 44. Each of the plurality of image cells 25 includes: an adhesive layer containing a light absorbent that absorbs light to generate heat and in contact with the transparent layer; and a diffraction layer having a diffraction grating to display an image. The first image cell is covered with a portion of the transparent part 44, the portion where no color change is induced in the heat-sensitive colorant, while the second image cell is covered with a portion of the transparent layer (transparent part), the portion where a color change is induced in the heat-sensitive colorant.

Description

  The technology of the present disclosure relates to an image display device that displays an image, a method for manufacturing the image display device, and a transfer ribbon.

  A passport, which is an example of a personal authentication medium, has an owner display unit that displays an owner's face image. Since the display of face images by posting face photos may be tampered with by changing the face photos, recent owner display units have reproduced the face images of owners on paper instead of posting face photos. Adopting fixing. Image reproduction methods include, for example, a method of reproducing a face image using fluorescent ink, a method of reproducing a face image using ink containing a colorless or light-colored fluorescent dye and a colored pigment, and a face using a pearl pigment. Methods for reproducing images are known (see, for example, Patent Documents 1, 2, and 3).

JP 2000-141863 A JP 2002-226740 A Japanese Patent Laid-Open No. 2003-170685

  However, even for a face image reproduced by the above-described image reproduction method, the visual effect of the face image is simple, so it is easy to forge or tamper, and the authenticity of the face image can be determined visually. Is difficult.

  An object of the technology of the present disclosure is to provide an image display device, a method for manufacturing an image display device, and a transfer ribbon that can easily determine whether an image is true or false by visual observation.

  An image display device that solves the above-described problems is composed of a transparent coating layer that includes a thermal colorant that changes color irreversibly at a temperature above the color change temperature and a transparent resin, a first image cell, and a second image cell. A plurality of image cells covered with the transparent covering layer. Each of the plurality of image cells includes an adhesive layer that includes a light absorbing agent that absorbs light to generate heat and is in contact with the transparent coating layer, and a diffraction layer having a diffraction grating for displaying an image. Then, the first image cell is covered with a transparent portion containing the thermal colorant which is not discolored in the transparent coating layer, and at least a part of the second image cell is in the transparent layer. It is covered with the colored part containing the thermal colorant which has changed color.

  A method of manufacturing an image display device that solves the above-described problem is a first transfer in which a part of a transfer layer formed on a transfer ribbon is transferred to an image receiving layer of an intermediate transfer ribbon to form a plurality of image cells on the intermediate transfer ribbon. A second transfer step of transferring the image receiving layer onto which the plurality of image cells have been transferred to a sheet, and a laser irradiation step of irradiating a part of the image cells with a laser. ,including. The transfer layer includes a light absorbing agent that absorbs light and generates heat, and adheres to the image receiving layer; a diffraction grating for displaying an image; the adhesive layer; and a substrate of the transfer ribbon; And a diffraction layer positioned between the two. The image receiving layer is a transparent coating layer that includes a heat-sensitive colorant that changes color irreversibly at a color change temperature or higher and a transparent resin, to which the adhesive layer adheres. In the laser irradiation step, in the part of the image cells, the light absorber contained in the adhesive layer is heated by a laser, and the part of the image receiving layer in contact with the part of the image cells Discolor the thermal colorant.

  According to the above configuration, when the adhesive layer of the image cell is heated to the color change temperature or higher, a colored portion is formed in the transparent coating layer in contact with the image cell. While the diffracted light from the first image cell is displayed as an image through the transparent layer, the diffracted light from the second image cell is weakened by the colored portion and is difficult to be visually recognized. Then, it is possible to determine whether the image displayed by the image display device is true or not based on whether the image displayed by the second image cell is included in the image displayed by the image display device. Moreover, even if the image displayed by the second image cell is included in the image displayed by the image display device, the image displayed by the second image cell depends on whether the image displayed by the second image cell is a predetermined image or not. It is possible to discriminate true / false. As a result, the authenticity of the image display device can be easily determined.

  In the image display device, the plurality of image cells include a plurality of first image cells, and each of the plurality of first image cells includes the diffraction gratings different from each other and have different wavelengths. It is preferable to direct the diffracted light toward a predetermined viewpoint.

According to the above configuration, since each of the plurality of first image cells directs diffracted light having different wavelengths to the viewpoint, an image viewed at the viewpoint is displayed as a color image including two or more colors. The color image displayed in the plurality of first image cells has a limited range of viewpoints to be visually recognized. Therefore, the visually recognized image varies greatly depending on the direction in which the image display device is visually recognized.
In the image display device, it is preferable that the second image cell includes a diffusion layer that diffuses light with respect to a predetermined viewpoint.

According to the above configuration, since the second image cell covered by the colored portion diffuses light with respect to the viewpoint, it is between the image displayed by the first image cell and the image displayed by the second image cell. In, differences such as edge strength in the image and shading in the image are widened.
In the image display device, it is preferable that the first image cell includes a transfer layer that has the diffraction grating and directs diffracted light toward a viewpoint, and a plurality of transfer layers different from each other overlap.
According to the above configuration, the image displayed by the image display device becomes fine.
In the image display device, it is preferable that the second image cell includes a transfer layer that directs diffracted light toward a viewpoint, and the transfer layer of the second image cell is covered with the diffusion layer.
According to the above configuration, the diffracted light from the transfer layer is diffused by the diffusion layer.

  In the image display device, the color change temperature of the thermal colorant is preferably higher than the glass transition temperature of the thermal adhesive included in the adhesive layer and the glass transition temperature of the transparent resin.

  According to the above configuration, the glass transition of the adhesive layer and the transparent coating layer is unlikely to occur in the manufacturing process of the image display device including the formation of the colored portion. Therefore, it is possible to prevent the image from becoming unclear.

  In the image display device manufacturing method, in the laser irradiation step, the partial image cell is preferably formed at a position for displaying a black plate image obtained from color separation of a color original image.

  According to the above configuration, the image cell to be irradiated with the laser is defined based on the black version of the color original image of the image indicated by the image display device. Therefore, the image displayed in the second image cell is a portion corresponding to the black plate in the color original image. As a result, the difference between the image displayed in the first image cell and the image displayed in the second image cell, such as the edge strength in the image and the contrast in the image, is widened.

  A transfer ribbon that solves the above problems is a transfer ribbon that includes a transfer layer that is transferred to an image receiving layer of an intermediate transfer ribbon, and the image receiving layer includes a thermal colorant that changes color irreversibly at a temperature higher than the color change temperature. The transfer layer includes a light absorber that absorbs light and generates heat; an adhesive layer that adheres to the image receiving layer; and a diffraction grating that forms an image. And a diffraction layer positioned between the transfer ribbon and the substrate.

  According to the above configuration, since the color of the thermal colorant changes due to the heat generated by the light absorber, a colored portion can be formed in a part of the transfer layer. Since the diffractive layer for forming an image is covered with the colored part and the transparent part, a part of the diffracted light from the diffractive layer is displayed as an image through the transparent part, while the other part of the diffracted light is displayed. Is weakened by the colored portion and becomes difficult to be visually recognized. As a result, it is possible to determine the authenticity of the image depending on whether or not the image displayed by the diffraction layer includes an image of light weakened by the colored portion.

  According to the technology of the present disclosure, it is easy to determine the authenticity of an image by visual observation.

It is a top view which shows the personal authentication medium provided with the image display part which is an example of the image display device in the technique of this indication in the state which opened the paper surface in which the image display part was provided. It is sectional drawing which shows the cross-section of an image display part. It is sectional drawing which shows the cross-section of a transfer ribbon. It is sectional drawing which shows the cross-section of an intermediate transfer ribbon. FIG. 6 is a cross-sectional view illustrating a state where image cells are transferred to an intermediate transfer ribbon. It is sectional drawing which shows the state by which the image cell was transcribe | transferred to the sheet | seat. It is process drawing which shows the patterning using a laser. It is a block diagram which shows an example of a structure of a transfer ribbon. It is a schematic diagram which shows typically an example of the color separation of a color original image with a face image. It is an apparatus block diagram which shows the structure of the apparatus which forms an image on a personal authentication medium. It is process drawing which shows the other patterning using a laser.

  An embodiment of an image display device, a method for manufacturing the image display device, and a transfer ribbon according to the technology of the present disclosure will be described with reference to FIGS.

[Configuration of Personal Authentication Medium 10]
As shown in FIG. 1, the personal authentication medium 10 is a booklet composed of a binding paper 11 and a cover 12, and has a plurality of paper surfaces 13. On the paper surface 13, paper surface information 14 such as a character string and a background pattern is printed. The paper surface 13 may include an IC chip in which personal information is recorded, an antenna for communicating with the outside in a non-contact manner, and the like.

  The cover 12 has a display function for displaying an image including personal information, and is folded in two so as to sandwich the binding paper 11. The personal information includes personal authentication information used for owner authentication, and is classified into, for example, biometric information and non-biometric personal information. The biometric information indicates a biometric feature of the owner. The biological information is, for example, at least one of a face, a fingerprint, a vein, and an iris, and is recorded in a format that can be read by an optical technique. Non-biological personal information is personal information other than biological information. Non-biological personal information is, for example, at least one of name, date of birth, age, blood type, gender, nationality, address, permanent address, telephone number, affiliation, and status. The non-biological personal information may be a character formed by typing, a handwritten signature of the owner, or a combination thereof.

The cover 12 includes a first image display unit 15, a second image display unit 16, a third image display unit 17, and a fourth image display unit 20.
The first image display unit 15, the second image display unit 16, and the third image display unit 17 are portions that store the wavelength of light and the amplitude of light, and use an absorption of light to display an image. indicate. For example, when white light is irradiated on the first image display unit 15, the second image display unit 16, and the third image display unit 17, each part of the first image display unit 15, the second image display unit 16 Each part and each part of the third image display unit 17 display an image that can be viewed by reflecting visible light according to the wavelength of light stored therein or the amplitude of light.

  The fourth image display unit 20 is a part that stores the wavelength of light, the amplitude of light, and the phase of light, and displays an image using light diffraction. For example, when the fourth image display unit 20 is irradiated with white light, each part of the fourth image display unit 20 diffracts light according to the wavelength of light stored therein, the amplitude of the light, and the phase of the light. Display an image that can be viewed.

  The first image display unit 15, the second image display unit 16, and the third image display unit 17 include, for example, a dye and a pigment as a forming material. The first image display unit 15, the second image display unit 16, and the third image display unit 17 are a thermal transfer recording method using a thermal head, an inkjet recording method, an electrophotographic method, or a combination of two or more of these. Formed by. In addition, the first image display unit 15, the second image display unit 16, and the third image display unit 17 may be formed by drawing with a laser beam on a layer containing a thermal color former. It may be formed by a combination of At least one of the second image display unit 16 and the third image display unit 17 may be formed by a thermal transfer recording method using a hot stamp, may be formed by a printing method, or a combination thereof. May be.

  The fourth image display unit 20 includes a hologram element having a diffraction grating. For example, the fourth image display unit 20 is formed by performing thermal transfer recording using a thermal head and thermal transfer recording using a hot stamp or a thermal roll in this order.

  The image displayed on the first image display unit 15 and the image displayed on the fourth image display unit 20 are the face images of the owner. The face image included in the image displayed by the first image display unit 15 and the face image included in the image displayed by the fourth image display unit 20 may have the same or different outer dimensions. Each of the image displayed on the first image display unit 15 and the image displayed on the fourth image display unit 20 may include other biological information instead of the face image. It may further include biological information. The image displayed by the fourth image display unit 20 may include non-biological personal information instead of the biological information, and may further include non-biological personal information in addition to the biological information. The image displayed by the fourth image display unit 20 may include non-personal information instead of personal information, and may further include non-personal information in addition to the personal information.

  The image displayed by the second image display unit 16 includes non-biological personal information and non-personal information. The image displayed by the second image display unit 16 is composed of, for example, one or more of characters, symbols, codes, and marks.

  The image displayed by the third image display unit 17 is a background pattern. For example, when the image displayed on the third image display unit 17 overlaps with the image displayed on the first image display unit 15 or the image displayed on the fourth image display unit 20, falsification of the personal authentication medium 10 is further suppressed. It is done.

[Configuration of Fourth Image Display Unit 20]
As shown in FIG. 2, the fourth image display unit 20 includes a sheet 21 constituting the cover 12 and a multilayer structure 22 positioned on the sheet 21. The multilayer structure 22 includes a plurality of image cells 25, an image receiving layer 43 that is an example of a transparent coating layer, and a peeling protective layer 42.

Each of the plurality of image cells 25 is located on a cell forming surface 21 a that is one surface of the sheet 21. The image receiving layer 43 covers each of the plurality of image cells 25 and also covers a portion of the cell forming surface 21 a of the sheet 21 that is not covered by the image cells 25. The image receiving layer 43 includes a transparent portion 44 and a colored portion 45 that is a part of the transparent portion 44, and the colored portion 45 covers at least a part of the image cell 25 selected from the plurality of image cells 25. ing.
The surface of the image cell 25 that faces the cell forming surface 21a is the lower surface of the image cell 25, and the colored portion 45 is not limited to the upper surface of the image cell 25, but the lower surface of the surfaces of the image cell 25. It suffices to cover at least a part of the surface to be in contact with the other surface. The peeling protective layer 42 covers the image receiving layer 43.

  The image cell 25 in contact with the transparent portion 44 among the plurality of image cells 25 is the first image cell 25a and is an image cell 25 in which the diffracted light from the image cell 25 is visually recognized. The image cell 25 that contacts the colored portion 45 among the plurality of image cells 25 is the second image cell 25b, and is an image cell 25 in which diffracted light from the image cell 25 is difficult to be visually recognized.

[Method for Manufacturing Fourth Image Display Unit 20]
Hereinafter, the configuration of the fourth image display unit 20 will be described together with the method for manufacturing the fourth image display unit 20.
The manufacturing method of the fourth image display unit 20 includes a first transfer process, a second transfer process, and a laser irradiation process. First, the transfer ribbon 30 used in the first transfer step will be described with reference to FIG. 3, and then the configuration of the intermediate transfer ribbon 40 will be described with reference to FIG.

As shown in FIG. 3, the transfer ribbon 30 includes a transfer substrate 31 and a transfer layer 32.
The transfer substrate 31 is, for example, a resin sheet including a resin film and a flat resin thin plate having a surface that is thicker than the resin film and sufficiently wider than the thickness. The transfer substrate 31 is formed of a material having excellent heat resistance such as polyethylene terephthalate, for example. The transfer substrate 31 is a substrate that supports the transfer layer 32, and a release layer containing, for example, a fluororesin or a silicone resin is provided on the surface of the transfer substrate 31 that supports the transfer layer 32. May be.

  The transfer layer 32 includes a release layer 33, a diffraction layer 34, a reflective layer 35, and an adhesive layer 36. A release layer 33, a diffraction layer 34, and a reflection layer 35 are located between the transfer substrate 31 and the adhesive layer 36, and a diffraction layer 34 is located between the release layer 33 and the reflection layer 35. ing.

  The release layer 33 is light-transmissive and typically transparent. The release layer 33 is made of, for example, a thermoplastic resin. When the adhesive layer 36 adheres to the intermediate transfer ribbon 40, the release layer 33 exhibits a function of smoothly advancing the release of the transfer layer 32 from the transfer substrate 31. Note that the release layer 33 may be omitted as long as the transfer layer 32 can be peeled from the transfer base material 31 with the adhesive layer 36 adhered to the intermediate transfer ribbon 40.

  The diffraction layer 34 includes a hologram element having a diffraction grating, and the hologram element may be a two-dimensional hologram element or a three-dimensional hologram element. The diffraction layer 34 is a transparent layer having a relief structure as a diffraction grating. As a material for forming the diffraction layer 34, a resin such as a photo-curing resin, a thermosetting resin, and a thermoplastic resin is used.

  The reflection layer 35 is, for example, a transparent reflection layer or an opaque metal reflection layer, and exhibits a function of improving the visibility of an image displayed by the diffraction layer 34 by reflecting light toward the diffraction layer 34. To do. The reflective layer 35 is formed by, for example, a vacuum film forming method such as vacuum deposition or sputtering. Note that the reflective layer 35 may be omitted as long as the image displayed by the diffraction layer 34 is visible.

  The transparent reflection layer is made of, for example, a transparent material having a refractive index different from that of the diffraction layer 34. The transparent reflective layer may have a single layer structure or a multilayer structure. The transparent reflection layer having a multilayer structure may repeat reflection interference inside the transparent reflection layer. As the transparent material, for example, a transparent dielectric such as zinc sulfide and titanium dioxide is used.

  The transparent reflective layer may be a metal layer having a thickness of less than 20 nm. As the material of the metal layer, for example, a single metal such as chromium, nickel, aluminum, iron, titanium, silver, gold, and copper, or an alloy thereof is used. For the opaque metal reflection layer, a metal layer that is the same metal layer as the metal layer used for the transparent reflection layer and is thicker than the transparent reflection layer is used.

  The adhesive layer 36 is made of, for example, a thermoplastic resin. The adhesive layer 36 includes a transparent resin and a light absorbent that absorbs light and generates heat. As the transparent resin, for example, a thermoplastic resin, a thermosetting resin, a moisture curable resin, or an ultraviolet ray or an electron beam curable resin is used. As the transparent resin, for example, an acrylic resin, a polyester resin, or a polyamideimide resin is used. As the light absorber, for example, an infrared absorber, an ultraviolet absorber, or a mixture thereof is used. A light absorber is suitably selected according to the wavelength of the laser used for a laser irradiation process.

  Examples of infrared absorbers include carbon materials such as carbon black, organometallic complexes such as phthalocyanine, azo, and thioamide, diiminium, anthraquinone, polymethine, azurenium, squarilium, and thiopyrylium. Organic infrared absorbers such as these, or a mixture thereof is used.

Examples of the ultraviolet absorber include salicylic acid-based ultraviolet absorbers such as phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxybenzophenone, 2-hydroxy- Benzophenone ultraviolet absorbers such as 4-octoxybenzophenone and 2-hydroxy-4-dodecyloxybenzophenone, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5 ′) -Tert-butylphenyl) benzotriazole-based UV absorbers such as benzotriazole, 2-ethylhexyl-2-cyano-3,3′-diphenyl acrylate, and shear such as ethyl-2-cyano-3,3-diphenyl acrylate Acrylate ultraviolet absorbers, or a mixture thereof is used. Further, as the ultraviolet absorbing material, an inorganic ultraviolet shielding material formed from fine powders such as TiO ₂ and ZnO is also used.

  The content of the light absorber is preferably about 0.1 parts by mass or more and about 20 parts by mass or less with respect to 100 parts by mass of the composition constituting the adhesive layer 36, for example. When the content of the light absorber is within such a range, sufficient heat is generated when the laser is irradiated, and the transparency and durability of the adhesive layer 36 are sufficiently secured.

  A back coat layer 37 is formed on the surface of the transfer substrate 31 opposite to the surface on which the transfer layer 32 is formed. The back coat layer 37 is made of, for example, silicon acrylate. When the transfer layer 32 is thermally transferred to the intermediate transfer ribbon 40, the backcoat layer 37 improves the adhesion between the thermal head and the transfer ribbon 30, and suppresses friction between the thermal head and the transfer ribbon 30. The function of increasing the thermal conductivity of the thermal head with respect to the transfer ribbon 30 is exhibited. The configuration in which the adhesion between the transfer substrate 31 and the thermal head is ensured, the configuration in which the friction between the transfer substrate 31 and the thermal head is sufficiently suppressed, and the thermal conductivity of the transfer substrate 31 is In the secured configuration, the back coat layer 37 may be omitted.

As shown in FIG. 4, the intermediate transfer ribbon 40 includes an intermediate transfer substrate 41, a peeling protection layer 42, and an image receiving layer 43.
The intermediate transfer substrate 41 is, for example, a resin sheet and a resin sheet including a flat resin thin plate having a surface that is thicker than the resin film and sufficiently wider than the thickness. The intermediate transfer substrate 41 is formed of a material having excellent heat resistance such as polyethylene terephthalate. The intermediate transfer substrate 41 is a substrate that supports the peeling protection layer 42 and the image receiving layer 43, and the surface of the intermediate transfer substrate 41 that supports them is, for example, a release material containing a fluororesin or a silicone resin. A mold layer may be provided.

  The peeling protective layer 42 is light transmissive and typically transparent. The peeling protective layer 42 is formed from, for example, a thermoplastic resin. The peeling protection layer 42 functions to stabilize the peeling when the image receiving layer 43 is peeled from the intermediate transfer substrate 41 and to increase the physical resistance of the surface of the image receiving layer 43.

  The image receiving layer 43 is formed of a material having good adhesion to the adhesive layer 36 of the transfer ribbon 30 and includes a heat sensitive adhesive. When the adhesive layer 36 of the transfer ribbon 30 is in close contact with the image receiving layer 43 and the transfer ribbon 30 is heated by the thermal head from the back coat layer 37 side, the image receiving layer 43 exhibits the function of transferring the transfer layer 32 thereto. .

  The image receiving layer 43 includes a transparent resin and a thermal colorant, and the thermal colorant changes its color irreversibly by being heated to a temperature higher than its color change temperature. As the thermal colorant, one that does not change color in the production of the intermediate transfer ribbon 40, the thermal transfer of the transfer layer 32 to the intermediate transfer ribbon 40, and the thermal transfer of the intermediate transfer ribbon 40 to the sheet 21 is used. In addition, a thermal colorant that does not change color even in a normal use environment of the personal authentication medium 10 is used. That is, as the heat-sensitive colorant, a color having a temperature higher than the glass transition temperature of the heat-sensitive adhesive constituting the image receiving layer 43 is used. The color change temperature of such a thermal colorant is, for example, about 200 ° C. or higher.

  As the thermal colorant, a substance known as a temperature indicating paint is used. For example, a thermochromic organic dye, a metal complex crystal, a mixture of an electron donating color developing compound, an electron accepting compound, and a polar organic compound is used as the thermal colorant. A mixture of these may be used as the thermal colorant.

  The content of the thermal colorant is preferably, for example, about 0.1 parts by mass or more and about 20 parts by mass or less with respect to 100 parts by mass of the composition constituting the image receiving layer 43. If the content of the thermal colorant is within such a range, the heat generation of the thermal colorant is sufficiently obtained in the laser irradiation step, and the performance of the image receiving layer 43 such as transparency and image receiving characteristics is sufficiently secured.

[First transfer process]
As shown in FIG. 5, in the first transfer step, the thermal ribbon is used from the back coat layer 37 side to the transfer ribbon 30 in a state where the adhesive layer 36 of the transfer layer 32 is in close contact with the image receiving layer 43 of the intermediate transfer ribbon 40. Local heating is performed. The thermal head is driven based on image data of an image displayed by the fourth image display unit 20. Thereafter, the transfer substrate 31 of the transfer ribbon 30 is peeled from the release layer 33. A transfer layer 32 transferred to the image receiving layer 43 is formed as an image cell 25 on the image receiving layer 43 of the intermediate transfer ribbon 40.

  The transfer layer 32 transferred by heating of the thermal head has a dot shape in a plan view facing the surface of the image receiving layer 43. The dot-shaped transfer layer 32 is positioned on a lattice point of a virtual planar lattice such as a square lattice, a triangular lattice, or a rectangular lattice on the surface of the image receiving layer 43.

  The diameter of the transfer layer 32 having a dot shape or the minimum center-to-center distance in the transfer layer 32 having a dot shape adjacent to each other is, for example, 0.085 mm or more and 0.169 mm or less, in other words, about 300 dpi or more. , Preferably about 150 dpi or less. When this dimension becomes large, it becomes difficult to display a high-definition image. On the contrary, when this dimension is reduced, the reproducibility of the pattern shape is lowered.

  Since the size of the heating element of the thermal head is limited, the resolution of a general thermal head is 0.021 mm or more and 0.011 mm or less, and the resolution is about 1200 dpi or more and 2400 dpi or less. Further, in order to transfer the transfer ribbon 30 having the diffractive layer 34, a larger energy is required as compared with a general color ribbon, the size of the thermal head is about 0.042 mm, and the resolution is About 600 dpi. If the pattern resolution of the image cell 25 is smaller than the resolution of the thermal head, it is easy to form a predetermined interval in the image cells 25 adjacent to each other.

[Second transfer step]
As shown in FIG. 6, in the second transfer step, the intermediate transfer ribbon 40 is heated while the image receiving layer 43 of the intermediate transfer ribbon 40 is in close contact with the sheet 21, and the intermediate transfer ribbon 40 is applied to the sheet 21. Pressurized. As a result, the image cell 25, the image receiving layer 43, and the peeling protection layer 42 are thermally transferred to the sheet 21. Thereafter, the intermediate transfer substrate 41 of the intermediate transfer ribbon 40 is peeled from the sheet 21. As a result, the image cell 25, the image receiving layer 43, and the peeling protection layer 42 are transferred to the sheet 21.

[Laser irradiation process]
As shown in FIG. 7, in the laser irradiation process, a laser 51 is irradiated from the laser unit 50 toward some of the image cells 25. As the laser 51 emitted from the laser unit 50, for example, a laser such as an Nd: YAG laser, an Nd: YVO ₄ laser, or a CO ₂ gas laser is applied.

  When the laser 51 is irradiated toward the image cell 25, the light absorber contained in the adhesive layer 36 of the image cell 25 generates heat. When the light absorber generates heat, the heat-sensitive colorant contained in the image receiving layer 43 that is in close contact with the adhesive layer 36 is heated to a color change temperature or higher. In the transparent portion 44 of the image receiving layer 43, the vicinity of the image cell 25, in particular, the vicinity of the portion that receives the laser 51 in the image cell 25 is changed to a colored portion 45 in which the thermal colorant has changed color. As a result, the plurality of image cells 25 are divided into a first image cell 25 a in contact with the transparent portion 44 and a second image cell 25 b in contact with the colored portion 45.

  According to such a configuration, when the sheet 21 is visually observed through the peeling protection layer 42, the diffracted light from the first image cell 25a is visually recognized, while the diffracted light from the second image cell 25b is the colored portion 45. It is hard to be visually recognized by. If the colored portion 45 has a light color density, the diffracted light from the second image cell 25b is visually recognized as light whose intensity is weakened. If the second image cell 25b does not include a diffraction grating, the diffracted light from the second image cell 25b is not visually recognized, and the color of the light reflected by the colored portion 45 is visually recognized.

[Fourth Image Display Unit 20 for Color Image]
In the method of manufacturing the fourth image display unit 20 that displays a color image, a color transfer ribbon 55 is used instead of the transfer ribbon 30. The color transfer ribbon 55 is mainly different from the transfer ribbon 30 in that a color diffraction layer 34 is provided.

  As shown in FIG. 8, the color transfer ribbon 55 has a red region 56, a green region 57, a blue region 58, and a diffusion region 59. The red region 56, the green region 57, the blue region 58, and the diffusion region 59 are repeated along the longitudinal direction of the color transfer ribbon 55. The red region 56, the green region 57, and the blue region 58 are regions having different diffraction gratings, and the diffusion region 59 is a region having a diffusion layer instead of the diffraction layer 34.

  When the red region 56 is viewed from a predetermined viewpoint, the pitch of the grating pattern in the diffraction grating of the red region 56 is such that the red diffracted light is viewed from the entire red region 56. In each position is different. The pitch of such a lattice pattern is determined based on geometric optical calculation using each position of the red region 56, the viewpoint, the incident angle of illumination light, and the like so that the first-order red diffracted light is visually recognized at the viewpoint. It is done.

  Similarly, when the green region 57 is viewed from a predetermined viewpoint, the pitch of the grating pattern in the diffraction grating of the green region 57 is such that green diffracted light is viewed from the entire green region 57. Each position in the green area 57 is different. When the blue region 58 is viewed from a predetermined viewpoint, the pitch of the grating pattern in the diffraction grating of the blue region 58 is such that the blue diffracted light is viewed from the entire blue region 58. In each position is different. On the other hand, the diffusion region 59 has a diffusion layer having a structure that diffuses and reflects light incident on the diffusion region 59.

  A positioning mark 60 is provided on the color transfer ribbon 55. The positioning mark 60 is a mark used for positioning at the time of transfer, and is used for positioning the color transfer ribbon 55 with respect to the thermal head. The positioning mark 60 is, for example, a mark from which diffracted light is emitted in a specific direction by a diffraction grating. Positioning using the positioning mark 60 is performed based on the detection result of the optical sensor, using a light source that irradiates the positioning mark 60 with illumination light and an optical sensor that detects diffracted light from the positioning mark 60.

  Next, image data used in the first transfer process in the manufacturing method of the fourth image display unit 20 that displays a color image will be described. The image data is data obtained from a result of imaging a human face by an imaging device or a result of reading a print including a human face. In FIG. 9, a data structure in which a color is associated with a two-dimensional position coordinate is shown in a pseudo manner using a face image.

  As shown in FIG. 9, the imaging result 61 obtained by the imaging device is data in which colors are associated with two-dimensional coordinate positions, and the imaging result 61 first includes red, green, and blue light. Are separated into the three primary colors. Accordingly, red face image data 62, green face image data 63, and blue face image data 64 are obtained from the imaging result 61. Further, the imaging result 61 is color-separated into three primary colors of yellow, magenta, and cyan ink and a black plate. As a result, diffusion face image data 65 corresponding to the black plate is obtained from the imaging result 61. The coordinate position included in the red face image data 62 is used to determine the heating position of the thermal head with respect to the red area 56. The coordinate position included in the green face image data 63 is used to determine the heating position of the thermal head with respect to the green area 57. The coordinate position included in the blue face image data 64 is used to determine the heating position of the thermal head with respect to the blue area 58. The coordinate position included in the diffusion face image data 65 is used to determine the heating position of the thermal head with respect to the diffusion region 59.

  In the first transfer step, transfer using the red region 56, the green region 57, the blue region 58, and the diffusion region 59 is sequentially performed on the image receiving layer 43 of the intermediate transfer ribbon 40.

  First, transfer using the red area 56 is performed based on the image data of the red face image data 62. At this time, the color transfer ribbon 55 is transferred to the space between the thermal head and the intermediate transfer ribbon 40 so that the red region 56 faces the transfer region of the intermediate transfer ribbon 40. Then, the red region 56 is positioned with respect to the thermal head using the positioning mark 60. When the positioning is completed, the thermal head is driven based on the image data of the red face image data 62 while appropriately transferring the color transfer ribbon 55, and the transfer layer 32 in the red area 56 is selectively transferred to the image receiving layer 43. The Then, by transferring the transfer ribbon 30, the transfer substrate 31 is peeled from the transfer layer 32 adhered to the image receiving layer 43. As a result, a pattern based on the red face image data 62 is formed on the intermediate transfer ribbon 40 by the transfer layer 32 in the red region 56.

  Such transfer of the transfer layer 32 is performed on the green region 57, the blue region 58, and the diffusion region 59. Thereby, the transfer layer 32 in the red region 56, the transfer layer 32 in the green region 57, the transfer layer 32 in the blue region 58, and the transfer layer 32 in the diffusion region 59 are selectively transferred to the image receiving layer 43. A cell 25 is formed. The image receiving layer 43 of the intermediate transfer ribbon 40 having such a transfer layer 32 displays a color face image. However, since the part of the diffusion face image data 65 has a diffusion structure, scattered light is visually recognized in a low luminance area in the face image, and as a result, the image is visually recognized as a different image from the normal color image. Is done.

  In the second transfer step, after the image cell 25, the image receiving layer 43, the peeling protective layer 42, and the intermediate transfer substrate 41 are thermally transferred to the sheet 21, the intermediate transfer substrate 41 is peeled off.

  In the laser irradiation step, the laser 51 is irradiated using the image data of the diffusion face image data 65. That is, the laser 51 is irradiated to the image cell 25 including the transfer layer 32 in the diffusion region 59 in the image cell 25, and a part of the transparent portion 44 of the image receiving layer 43 is changed to the colored portion 45. As a result, the first pattern constituted by the first image cell 25a in which the diffracted light is easily visible and the second pattern constituted by the second image cell 25b in which the diffracted light is difficult to visually recognize are included. A fourth image display unit 20 is formed.

  At this time, the first image cell 25a may have a single transfer layer 32 or a plurality of transfer layers 32 overlapping each other in the first transfer step. Further, in the plurality of second image cells 25b, the image cells 25 adjacent to each other may be spaced apart from each other, or the image cells 25 adjacent to each other may be in contact with each other. If the method is such that the second image cells 25b adjacent to each other are formed at a predetermined interval, even if the irradiation position of the laser 51 is shifted, the laser 51 is irradiated to a portion where the light absorber is not present. Cheap. As a result of the color change of the transparent portion 44 being less likely to occur due to the shift of the irradiation position of the laser 51, the image is not displayed as the irradiation position of the laser 51 is shifted, and the irradiation position of the laser 51 is shifted. Compared to the case where there is no image, an image with a light color change is displayed.

  The image displayed by the second image cell 25b having the diffusion structure is a black portion in the image, that is, an image portion displayed by the second pattern, and is visually recognized as a tighter black image. Further, since the color portion in the image, that is, the image portion displayed by the first pattern is composed of light by diffracted light, the image corresponding to the black plate portion is an image displayed by simple light reflection. Are very different. Since the diffracted light image has a limited viewable range, it is not visible when the image is out of the range. However, in the image portion corresponding to the laser patterning, the visible range is the diffracted light image view. It is wider than possible. For this reason, the image changes greatly depending on the viewing direction due to the difference in the visible range of these images.

  As described above, since the fourth image display unit 20 is an image having a characteristic visual effect, it is possible to easily determine authenticity. In addition, the fourth image display unit 20 having such a more complicated and special visual effect is difficult to reproduce, and therefore, it is difficult to tamper with, and it is possible to easily and reliably determine whether the image is true or false. Is possible.

An example of the printer 70 that forms the fourth image display unit 20 on the personal authentication medium 10 will be described with reference to FIG.
As shown in FIG. 10, the printer 70 includes an insertion unit 71, and the insertion unit 71 guides the personal authentication medium 10 before the fourth image display unit 20 is formed to the primer unit 72. The primer unit 72 includes a primer unwinding 73, a primer winding 74, a primer transfer head 75, and a primer platen roll 76. The primer unit 72 performs a primer transfer process by bringing the primer ribbon 77 into close contact with the personal authentication medium 10 guided in the apparatus and transferring the primer layer of the primer ribbon onto the surface of the personal authentication medium 10.

  The primer ribbon 77 is a ribbon for forming on the cell forming surface 21a a primer layer that enhances the adhesion between the cell forming surface 21a of the personal authentication medium 10 and the adhesive layer 36 of the transfer layer 32. The primer ribbon includes a primer layer that is releasably supported on a roll-shaped substrate, and the material of the primer layer includes a heat-sensitive adhesive.

  The first transfer unit 78 brings the color transfer ribbon 55 sent by the transfer ribbon unwinding 79 and the transfer ribbon take-up 80 into close contact with the intermediate transfer ribbon 40 sent from the intermediate transfer ribbon unwinding 82. Then, the first transfer unit 78 performs a first transfer process of transferring the transfer layer 32 of the color transfer ribbon 55 to the intermediate transfer ribbon 40 using the image transfer head 83 and the image platen roll 84.

  Note that the first transfer step and the primer transfer step can proceed simultaneously. Then, by transferring the transfer layer 32 simultaneously with the introduction of the personal authentication medium 10, the time required to proceed to the next step is shortened, and the total printing time can be shortened.

  The intermediate transfer ribbon 40 onto which the image cell 25 has been transferred is taken up by an intermediate transfer ribbon take-up 85. The personal authentication medium 10 to which the primer layer has been transferred is carried by a conveyor, and after the position of the image of the intermediate transfer ribbon 40 and the transfer position of the personal authentication medium 10 are adjusted, the intermediate transfer ribbon 40 is moved. And the personal authentication medium 10 are in close contact with each other.

  The intermediate transfer ribbon 40 and the personal authentication medium 10 enter the thermal transfer unit 86 while being in close contact with each other. In the thermal transfer unit 86, the intermediate transfer ribbon 40 is heated and pressed against the personal authentication medium 10, whereby the image cell 25, the image receiving layer 43, and the peeling protective layer transferred to the intermediate transfer ribbon 40. 42 is thermally transferred to the personal authentication medium 10. Here, the intermediate transfer substrate 41 of the intermediate transfer ribbon 40 is peeled off by the intermediate transfer ribbon take-up 85, and the outermost surface of the personal authentication medium 10 becomes the peel protection layer 42.

  Thereafter, the personal authentication medium 10 is positioned by the conveyor, and then receives the laser 51 from the laser unit 50, whereby further laser patterning is performed on the portion where the fourth image display unit 20 is transferred.

The personal authentication medium 10 for which patterning has been completed is discharged from the apparatus by a booklet discharge unit 89. Thereby, the patterning for the personal authentication medium 10 is completed.
According to the above embodiment, the effects listed below can be obtained.
(1) Since the fourth image display unit 20 has a characteristic visual effect, authenticity determination of the personal authentication medium 10 is easy.
(2) Since each of the plurality of image cells 25 directs light having different wavelengths to a predetermined viewpoint, the fourth image display unit 20 can display an image as a color image.
(3) The image displayed on the fourth image display unit 20 varies depending on the direction in which the fourth image display unit 20 is viewed.

(4) The diffracted light of the first image cell 25a is directed to a predetermined viewpoint, while the diffracted light of the second image cell 25b is diffused, so that the image displayed by the first pattern and the second Differentiation from the image displayed by the pattern is achieved.
(5) Since the first image cell 25a has the plurality of transfer layers 32 overlapping each other, the fineness of the image displayed on the fourth image display unit 20 is increased.

  (6) In the second image cell 25b, for example, since the transfer layer 32 of the diffusion region 59 is superimposed on the transfer layer 32 of the red region 56, the fineness of the image displayed on the fourth image display unit 20 is increased.

  (7) The color change temperature of the thermal colorant contained in the image receiving layer 43 is higher than the glass transition temperature of the heat sensitive adhesive contained in the adhesive layer 36 and the glass transition temperature of the transparent resin contained in the image receiving layer 43. Therefore, glass transition hardly occurs in the adhesive layer 36 and the image receiving layer 43 in the manufacturing process of the fourth image display unit 20. As a result, the image displayed by the first pattern and the image displayed by the second pattern are not easily obscured due to the glass transition of the adhesive layer 36 and the image receiving layer 43.

  (8) Since a predetermined interval is formed in the image cells 25 adjacent to each other, even if the irradiation position of the laser 51 is deviated, the influence of the deviation of the irradiation position on the image can be suppressed.

In addition, the said embodiment can also be suitably changed and implemented as follows.
The resolution of laser patterning is, for example, 0.002 mm or more and 0.001 mm or less, and the resolution can be set to about 12700 dpi or more and 25400 dpi or less. That is, the patterning resolution by the laser can be set to about 10 times or more compared with the patterning resolution by the thermal head. For this reason, the patterning of the image by the laser can express more finely than the patterning of the image by the thermal head.

  As shown in FIG. 11, when the laser 51 is irradiated to the image cell 25 from the laser unit 50 having a higher resolution than that of the thermal head, the colored portion 45 is formed in the image receiving layer 43 in a range smaller than the portion in contact with the image cell 25. Is formed.

  According to such a configuration, when the personal authentication medium 10 is viewed from the peeling protective layer 42 side, since the colored portion 45 is smaller than the second image cell 25b, the colored portion 45 is in the portion of the second image cell 25b. Is displayed as well as an image of diffracted light from the second image cell 25b.

  Further, a fine shadow can be expressed by superimposing a black image displayed by the high-resolution colored portion 45 on a color image displayed by each color. Therefore, it is possible to display an image that is easier to recognize than an image using only diffracted light. In particular, such a high-resolution shading is effective for a configuration that displays details of a face image.

  The irradiation position of the laser 51 in the laser irradiation step is not limited to the position where the black plate image obtained from the color separation of the color original image is displayed, but can be appropriately changed according to the content of the displayed image.

In the range where the clarity of the image displayed by the fourth image display unit 20 is ensured, the color change temperature of the thermal colorant is the glass transition temperature of the thermal colorant of the adhesive layer 36 and the transparent resin of the image receiving layer 43. It may be lower than the glass transition temperature.
The second image cell may be formed of only the second transfer layer, that is, the transfer layer 32 in the diffusion region 59 in the above embodiment.

The transfer layer included in the first image cell 25a may be configured to direct diffracted light having a predetermined wavelength to the viewpoint, and the wavelength of the diffracted light directed to the viewpoint may be two or less.
The second image cell 25b only needs to be the image cell 25 covered with the colored portion 45, and the second image cell may not include the second transfer layer.

  The sheet 21 may be other than paper, for example, a plastic substrate, a metal substrate, a ceramic substrate, or a glass substrate.

The image displayed by the image display device may include other biological information in addition to the face image, or may include other biological information instead of the face image. The image displayed by the image display device may include at least one of non-biological personal information and non-personal information in addition to biometric information, or non-biological personal information and non-personal information instead of biometric information. May be included.
The image displayed by the image display device is not limited to the face image of the owner, and may be, for example, letters, numbers, symbols, figures, patterns, or combinations thereof.
-The image display medium is not limited to the personal authentication medium 10, for example, credit card, driver's license, employee ID card, membership card ID card, entrance examination voucher, passport, banknote, gift certificate, point It may be a card, stock certificate, securities, lottery ticket, horse ticket, bank passbook, boarding ticket, pass ticket, air ticket, admission ticket for various events, play ticket, prepaid card for transportation or public telephone.

  DESCRIPTION OF SYMBOLS 10 ... Personal authentication medium, 11 ... Binding paper, 12 ... Cover, 13 ... Paper surface, 14 ... Paper surface information, 15 ... 1st image display part, 16 ... 3rd image display part, 17 ... 3rd image display part, 20 ... Fourth image display unit, 21 ... sheet, 21a ... cell forming surface, 22 ... multilayer structure, 25 ... image cell, 25a ... first image cell, 25b ... second image cell, 30 ... transfer ribbon, 31 ... Base material 32 ... Transfer layer 33 ... Release layer 34 ... Diffraction layer 35 ... Reflective layer 36 ... Adhesive layer 37 ... Back coat layer 40 ... Intermediate transfer ribbon 41 ... Intermediate transfer substrate 42 ... Peel Protective layer, 43 ... image receiving layer, 44 ... transparent portion, 45 ... colored portion, 50 ... laser unit, 51 ... laser, 55 ... transfer ribbon, 56 ... red region, 57 ... green region, 58 ... blue region, 59 ... diffusion Area 60 ... Positioning mark 61 ... Color face image 70 ... Printer, 71 ... Insertion unit, 72 ... Primer unit, 73 ... Primer unwinding, 74 ... Primer winding, 75 ... Primer transfer head, 76 ... Primer platen roll, 77 ... Primer ribbon, 78 ... First transfer unit, 79: Transfer ribbon winding, 80: Transfer ribbon winding, 82: Intermediate transfer ribbon winding, 83: Image transfer head, 84 ... Image platen roll, 85 ... Intermediate transfer ribbon winding, 85 ... Positioning mark, 86 ... Thermal transfer Unit, 89 ... Booklet discharge unit.

Claims (9)

A transparent coating layer containing a heat-sensitive colorant and a transparent resin that irreversibly changes color at a temperature higher than the color change temperature;
A plurality of image cells that are composed of a first image cell and a second image cell and are covered with the transparent coating layer;
With
Each of the plurality of image cells is
Comprising an adhesive layer in contact with the transparent coating layer containing a light absorber that absorbs light and generates heat;
The first image cell is
A diffraction layer having a diffraction grating for displaying an image;
Covered with a portion containing the thermal colorant that is not discolored in the transparent coating layer,
At least a portion of the second image cell is
An image display device covered with a portion containing the heat-sensitive colorant that is discolored in the transparent coating layer. The plurality of image cells includes a plurality of the first image cells;
Each of the plurality of first image cells includes:
The image display device according to claim 1, comprising the diffraction gratings different from each other and directing diffracted lights having different wavelengths toward a predetermined viewpoint. The image display device according to claim 2, wherein the second image cell includes a diffusion layer that diffuses light with respect to a predetermined viewpoint. The first image cell includes a transfer layer that has the diffraction grating and directs diffracted light toward a viewpoint.
The image display device according to claim 2, wherein a plurality of transfer layers different from each other overlap. The second image cell includes a transfer layer having a diffraction grating and directing diffracted light toward a viewpoint,
The image display device according to claim 3, wherein the transfer layer of the second image cell is covered with the diffusion layer. The image display device according to any one of claims 1 to 5, wherein a color change temperature of the thermal colorant is higher than a glass transition temperature of the thermal adhesive included in the adhesive layer and a glass transition temperature of the transparent resin. . A first transfer step of transferring a part of the transfer layer formed on the transfer ribbon to the image receiving layer of the intermediate transfer ribbon to form a plurality of image cells on the intermediate transfer ribbon;
A second transfer step of transferring the image receiving layer onto which the plurality of image cells have been transferred to a sheet;
A laser irradiation step of irradiating a part of the plurality of image cells with a laser.
The transfer layer includes a light absorber that absorbs light and generates heat, and an adhesive layer that adheres to the image receiving layer;
A diffraction layer having a diffraction grating for displaying an image and positioned between the adhesive layer and a base material of the transfer ribbon,
The image receiving layer is a transparent coating layer to which the adhesive layer adheres, including a thermosensitive colorant and a transparent resin that irreversibly changes color at a color change temperature or higher,
In the laser irradiation step,
In some of the image cells, the light absorbing agent contained in the adhesive layer is heated by a laser, and the thermal colorant is discolored in a portion of the image receiving layer in contact with the some image cells. Device manufacturing method. In the laser irradiation step,
The method of manufacturing an image display device according to claim 7, wherein the partial image cell is formed at a position for displaying a black plate image obtained from color separation of a color original image. A transfer ribbon having a transfer layer transferred to the image receiving layer of the intermediate transfer ribbon,
The image receiving layer is
A transparent layer containing a thermal colorant that irreversibly changes color above the discoloration temperature,
The transfer layer is
An adhesive layer that contains a light absorber that absorbs light and generates heat, adheres to the image receiving layer, and has a diffraction grating for forming an image, and is positioned between the adhesive layer and the transfer ribbon substrate. A transfer ribbon comprising: a diffraction layer;