JP2011083998A - Image display body, method for manufacturing the same, personal authentication medium, and blank medium - Google Patents

Abstract

It is possible to record an image on a diffraction grating array on demand without using a laser beam.
An image display according to the present invention includes a plurality of cells C1 to C3 arranged in the X and Y directions, and each of the cells C1 to C3 has a transparent diffraction grating having a relief-type diffraction grating provided on the surface thereof. A blank medium including a structure forming portion is prepared, and a transparent material layer P _L is formed or diffracted on a region made of a diffraction grating in the surface of the diffractive structure forming portion included in a part of the cells C1 to C3. The liquid can be obtained by supplying a solution for dissolving the structure forming portion to reduce or reduce the diffraction efficiency of the diffraction grating in at least a part of the region.
[Selection] Figure 2

Description

  The present invention relates to an image display technique that can be used for personal authentication, for example.

  Many personal authentication media such as passports and ID (identification) cards use facial images to enable visual personal authentication.

  For example, in a passport, conventionally, photographic paper on which a face image is printed is pasted on a booklet. However, such passports may be tampered with by reprinting photographic prints.

  For these reasons, in recent years, there is a tendency to digitize facial image information and reproduce it on a booklet. As this image reproduction method, for example, a thermal transfer recording method using a transfer ribbon has been studied.

  However, recently, thermal transfer recording type printers using sublimation dyes or colored thermoplastic resins are widely used. Considering this situation, it is not always difficult to remove a face image from a passport and record another face image on the face image.

  Patent Document 1 describes that a face image is recorded by the method described above, and a face image is recorded thereon using fluorescent ink. Patent Document 2 describes that a face image is recorded using an ink containing a colorless or light-colored fluorescent dye and a colored pigment. Further, Patent Document 3 describes that a normal face image and a face image formed using a pearl pigment are arranged side by side.

  When these technologies are applied to a passport, the alteration becomes more difficult. However, a face image recorded using a fluorescent material cannot be observed unless a special light source such as an ultraviolet lamp is used. In addition, although a face image formed using a pearl pigment can be visually recognized with the naked eye, it is difficult to form a high-definition image using this because the pearl pigment has a large particle size.

  Patent Document 4 describes disposing a plurality of cells each composed of a diffraction grating and destroying a part of the cells by laser beam irradiation. Since the broken portion cannot emit diffracted light, the diffraction grating array including these cells displays a diffraction image corresponding to the non-destructive portion.

  Usually, the image displayed by the diffraction grating array can be viewed with the naked eye. Further, according to the diffraction grating array, superior image quality can be achieved as compared with the case where a pearl pigment is used. The technique described in Patent Document 4 is suitable for recording an image on demand, and is expected to be applied to recording personal information.

JP 2000-141863 A JP 2002-226740 A Japanese Patent Laid-Open No. 2003-170685 JP-A-8-29609

  However, when laser beam irradiation is used, there is a possibility that the material is carbonized in the laser beam irradiation part and the irradiation part becomes black.

  It is an object of the present invention to enable on-demand recording of images on a diffraction grating array without using a laser beam.

  The first aspect of the present invention includes a plurality of cells arranged in first and second directions intersecting each other, each of the plurality of cells forming a transparent diffraction structure having a relief-type diffraction grating provided on the surface thereof A blank medium including a portion is prepared, and a transparent material layer is formed on a region made of the diffraction grating in the surface of the diffractive structure forming portion included in a part of the plurality of cells, or the diffractive structure It is an image display body obtained by supplying a liquid that dissolves the formation part and reducing or reducing the diffraction efficiency of the diffraction grating to zero or at least in a part of the region.

  According to a second aspect of the present invention, in the plurality of cells, the diffraction efficiency of the diffraction grating is zero or reduced in at least a part of the region, and the diffraction efficiency of the diffraction grating occupying the region is zero. It is the image display body which concerns on the 1st side surface containing two or more cells from which the ratio of the part which is or is reduced differs.

  The third aspect of the present invention is the image according to the first or second aspect, wherein the plurality of cells further include a reflective layer covering at least a portion of the region where the diffraction efficiency of the diffraction grating is not reduced. It is a display.

  According to a fourth aspect of the present invention, in the blank medium, adjacent ones of the plurality of cells in the first direction have different lattice constants of the diffraction grating and / or length directions of the grooves. It is an image display body concerning any one of the 1st thru / or the 4th side.

  According to a fifth aspect of the present invention, the blank medium is disposed between the plurality of cells adjacent to each other in the first direction, and the position of the top is higher than the bottom of the groove of the diffraction grating. It is an image display body which concerns on the 4th side surface further provided with the some protrusion.

  The sixth aspect of the present invention is the image display body according to the fifth aspect, wherein the plurality of protrusions extend in the second direction and are a plurality of partition walls arranged in the first direction.

  A seventh aspect of the present invention is the image display according to the fifth aspect, wherein the plurality of protrusions are arranged in the first and second directions.

  In an eighth aspect of the present invention, the first and second directions are orthogonal to each other, and the cells adjacent to the second direction among the plurality of cells are the lattice constant of the diffraction grating and the length of the groove. It is an image display body which concerns on any one of the 5th thru | or 7th side surface where directions are mutually equal.

  A ninth aspect of the present invention relates to a personal authentication comprising a base material for displaying an image including personal information, and the image display body according to any one of claims 1 to 8 supported by the base material. It is a medium.

  According to a tenth aspect of the present invention, the image displayed by the image display body includes first personal information, the image displayed by the base material includes second personal information, and the first and second personal information are the same person. It is the personal authentication medium which concerns on the 9th side which is the information of.

  An eleventh aspect of the present invention is the personal authentication medium according to the tenth aspect, wherein at least one of the first and second personal information includes biometric information.

  A twelfth aspect of the present invention comprises a plurality of high efficiency cells each including a diffraction grating, and a low efficiency cell in which at least a portion of the diffraction efficiency of each of the diffraction gratings is zeroed or reduced. A blank medium used for manufacturing an image display body, each including a transparent diffractive structure forming portion provided with a relief-type diffraction grating on the surface, arranged in first and second directions intersecting each other, Adjacent ones in the first direction are between a plurality of cells whose lattice constants and / or groove length directions of the diffraction gratings are different from each other and those adjacent to each other in the first direction among the plurality of cells. And a plurality of protrusions having a height higher than that of the region made of the diffraction grating in the surface.

  A thirteenth aspect of the present invention includes a plurality of cells arranged in first and second directions intersecting each other, each of the plurality of cells forming a transparent diffraction structure having a relief-type diffraction grating provided on a surface thereof A blank medium including a portion is prepared, and a transparent material layer is formed on a region made of the diffraction grating in the surface of the diffractive structure forming portion included in a part of the plurality of cells, or the diffractive structure It is a method for manufacturing an image display body, which includes supplying a solution for dissolving a forming portion and reducing or reducing the diffraction efficiency of the diffraction grating to zero in at least a part of the region.

  According to the present invention, it is possible to record an image on a diffraction grating array on demand without using a laser beam.

  In the image display body according to the first aspect of the present invention, a transparent material layer is formed on a region composed of a diffraction grating in a surface of a diffraction structure forming unit included in a part of a plurality of cells, or the diffraction structure forming unit Is obtained by supplying a liquid that dissolves the liquid crystal so that the diffraction efficiency of the diffraction grating becomes zero or reduced in at least a part of this region. In the cell of such an image display body, carbonization due to laser beam irradiation does not occur. Therefore, the influence of this carbonization on the image quality can be eliminated.

  In the image display body according to the second aspect of the present invention, the diffraction efficiency of the diffraction grating of the plurality of cells is zero or reduced in at least a part of the region and the diffraction grating occupies the region. Includes two or more cells having different ratios of zero or being reduced. When this structure is employed, gradations corresponding to the above ratio can be displayed in these cells.

  In the image display body according to the third aspect of the present invention, each of the plurality of cells further includes a reflective layer covering at least a portion of the above-mentioned region where the diffraction efficiency of the diffraction grating is not reduced. When this reflective layer is provided, the visibility of the image displayed by the diffraction structure is improved.

  The image display body which concerns on the 4th side surface of this invention is obtained using the blank medium from which the lattice constant of a diffraction grating and / or the length direction of a groove | channel differ between the cells adjacent to a 1st direction. When such a blank medium is used, an image display body that displays a color image and / or a stereoscopic image is obtained.

  The image display body according to the fifth aspect of the present invention uses a blank medium having a plurality of protrusions whose top portions are higher than the bottom portions of the grooves of the diffraction grating between cells adjacent in the first direction. Is obtained. When this blank medium is used, when the ink for forming the transparent material layer or the liquid for dissolving the diffractive structure forming portion is supplied onto a certain cell, the ink or the liquid is not applied to the previous cell. It is possible to prevent spreading to cells adjacent in the first direction.

  In the image display body according to the fifth aspect of the present invention, the protrusions are a plurality of partition walls each extending in the second direction and arranged in the first direction. This structure can be used regardless of the viscosity of the ink for forming the transparent material layer or the liquid for dissolving the diffraction structure forming portion.

  In the image display body according to the seventh aspect of the present invention, the protrusions are arranged in the first and second directions. This structure is advantageously used particularly when the viscosity of the ink for forming the transparent material layer or the liquid for dissolving the diffraction structure forming portion is high.

  In the image display body according to the eighth aspect of the present invention, the first and second directions are orthogonal to each other, and those adjacent to the second direction among the plurality of cells are the lattice constant of the diffraction grating and the length of the groove. The direction is equal to each other. When this structure is adopted, even if the position for supplying the ink for forming the transparent material layer or the liquid for dissolving the diffraction structure forming portion is slightly shifted in the second direction, the effect of this shift on the image quality is not affected. small.

  A personal authentication medium according to a ninth aspect of the present invention includes the image display body according to any one of the first to eighth aspects. Therefore, this personal authentication medium is difficult to tamper with in addition to displaying an image of excellent image quality.

  In the personal authentication medium according to the tenth aspect of the present invention, the image displayed by the image display includes first personal information, the image displayed by the base material includes second personal information, and the first and second personal information are Information about the same person. Such a personal authentication medium is more difficult to falsify than a personal authentication medium in which only one of the image display body and the base material displays personal information.

  In the personal authentication medium according to the eleventh aspect of the present invention, at least one of the first and second personal information includes biometric information. Since biometric information is unique to an individual, it is particularly useful for personal authentication.

  The blank medium according to the twelfth aspect of the present invention includes a plurality of protrusions having a height higher than that of a region made of a diffraction grating between cells adjacent in the first direction. When this structure is adopted, when ink for forming a transparent material layer or a liquid for dissolving the diffraction structure forming portion is supplied onto a certain cell, the ink or liquid is applied to the previous cell. It is possible to prevent spreading to cells adjacent in the first direction.

  In the method for manufacturing an image display body according to the thirteenth aspect of the present invention, a transparent material layer is formed or diffracted on a region composed of a diffraction grating in the surface of the diffraction structure forming portion included in a part of a plurality of cells. A liquid for dissolving the structure forming portion is supplied to reduce or reduce the diffraction efficiency of the diffraction grating in at least a part of this region. In this method, carbonization due to laser beam irradiation does not occur. Therefore, the influence of this carbonization on the image quality can be eliminated.

The top view which shows roughly the personal authentication medium which concerns on the 1st aspect of this invention. The top view which expands and shows a part of personal authentication medium shown in FIG. Sectional drawing which expands and shows a part of personal authentication medium shown in FIG. The top view which shows roughly an example of the blank medium which can be used for manufacture of the personal authentication medium shown in FIG. Sectional drawing of the blank medium shown in FIG. The perspective view which shows roughly an example of the manufacturing apparatus which can be used for manufacture of the personal authentication medium shown in FIG. FIG. 7 is a diagram schematically showing a part of an ink jet print head included in the manufacturing apparatus shown in FIG. 6. The perspective view which shows roughly the modification of a blank medium. The perspective view which shows the other modification of a blank medium roughly. The perspective view which shows schematically the other modification of a blank medium. Sectional drawing which shows schematically the personal authentication medium which concerns on the 2nd aspect of this invention. The top view which shows roughly an example of the blank medium which can be utilized for manufacture of the image display body which displays a stereo image. The top view which shows roughly the other example of the blank medium which can be utilized for manufacture of the image display body which displays a stereo image. The figure which shows an example of the imaging | photography method of a stereo image roughly. The figure which shows roughly the element image obtained by image-processing one of the images image | photographed by the method shown in FIG. FIG. 15 is a diagram schematically showing an element image obtained by performing image processing on another image captured by the method shown in FIG. 14. The perspective view which shows a mode that the image display body is displaying the stereo image roughly. The top view which shows roughly an example of the blank medium which can be used for manufacture of the image display body which displays the combination of a stereo image and a plane image. The figure which shows schematically an example of the imaging | photography method of a stereo image and a plane image. FIG. 20 is a diagram schematically showing one of images taken by the method shown in FIG. 19. FIG. 20 is a diagram schematically showing another one of images taken by the method shown in FIG. 19. FIG. 20 is a diagram schematically showing still another image taken by the method shown in FIG. 19.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same referential mark is attached | subjected to the component which exhibits the same or similar function through all the drawings, and the overlapping description is abbreviate | omitted.

FIG. 1 is a plan view schematically showing a personal authentication medium according to the first aspect of the present invention.
A personal authentication medium 100 shown in FIG. 1 is a booklet such as a passport. FIG. 1 shows the booklet in an open state.

This personal authentication medium 100 includes a signature 1 and a cover 2.
The signature 1 is composed of one or more pieces of paper 11. Typically, a print pattern 12 such as a character string and a background pattern is provided on the paper piece 11. The signature 1 is formed by folding one paper piece 11 or a bundle of a plurality of paper pieces 11 into two. The paper piece 11 may include an IC (integrated circuit) chip in which personal information is recorded, an antenna that enables non-contact communication with the IC chip, and the like.

  The cover 2 is folded in half. The cover 2 and the signature 1 are overlapped so that the signature 1 is sandwiched between the covers 2 in a state where the booklet is closed, and are integrated by binding or the like at the positions of the folds.

  The cover 2 displays an image including personal information. This personal information includes personal authentication information used for personal authentication. This personal information can be classified into, for example, biological information and non-biological personal information.

  The biological information is unique to the individual among the characteristics of the biological body. Typically, biometric information is a feature that can be identified by optical techniques. For example, the biometric information is at least one image or pattern of a face, fingerprint, vein, and iris.

  Non-biological personal information is personal information other than biological information. For example, the non-biological personal information is 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 include characters input by typing, may include characters input by machine reading a handwriting such as a signature, or may include both of them. .

In FIG. 1, the cover 2 displays images I1a, I1b, I2 and I3.
The images I1a, I2 and I3 are images displayed using light absorption. Specifically, the images I1a, I2, and I3 are images that are visible when illuminated with white light and observed with the naked eye. One or more of the images I1a, I2 and I3 may be omitted.

  The images I1a, I2 and I3 can be composed of, for example, dyes and pigments. In this case, the images I1a, I2 and I3 can be formed by a thermal transfer recording method using a thermal head, an ink jet recording method, an electrophotographic method, or a combination of two or more thereof. Alternatively, the images I1a, I2 and I3 can be formed by forming a layer containing a thermal color former and drawing on this layer with a laser beam. Alternatively, a combination of these methods can be used. At least a part of the images I2 and I3 may be formed by a thermal transfer recording method using a hot stamp, may be formed by a printing method, or may be formed using a combination thereof.

  The image I1b is an image displayed by the hologram and / or the diffraction grating. As will be described in detail later, the image I1b is formed by, for example, an ink jet recording method.

  The images I1a and I1b include face images of the same person. The face image included in the image I1a and the face image included in the image I1b may be the same or different. The face image included in the image I1a and the face image included in the image I1b may have the same or different dimensions. Each of the images I1a and I1b may include other biological information instead of the face image, and may further include biological information other than the face image in addition to the face image.

  The image 11b 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. In addition, the image 11b may include non-personal information instead of personal information, and may further include non-personal information in addition to the personal information.

  The image I2 includes non-biological personal information and non-personal information. The image I2 forms, for example, one or more of characters, symbols, codes, and marks.

  The image I3 is a background pattern. For example, when the image I3 and at least one of the images 11a and 11b are combined, the personal authentication medium 100 can be made more difficult to falsify.

Next, the structure of the cover 2 will be described with reference to FIGS.
FIG. 2 is an enlarged plan view showing a part of the personal authentication medium shown in FIG. FIG. 3 is an enlarged cross-sectional view of a part of the personal authentication medium shown in FIG. The structure shown in FIGS. 2 and 3 is a portion corresponding to the image I1b in the cover 2.

As shown in FIG. 3, the cover 2 includes a cover main body 21 and an image display body 22.
The cover main body 21 is a base material of the personal authentication medium 100 and is typically a piece of paper. The cover main body 21 may have a single layer structure or a multilayer structure. The cover body 21 is folded in half so as to sandwich the signature 1 in a state where the personal authentication medium 100 is closed.

  The image display body 22 is a layer having a multilayer structure. The image display body 22 is affixed to the main surface of the cover body 21 that faces the signature 1 when the personal authentication medium 100 is closed.

  The image display body 22 includes an image display layer (not shown) that displays at least a part of the images I1a, I2 and I3. The image displayed by the image display layer typically includes an image I1a.

  The image display layer displays at least a part of the images I1a, I2 and I3 using light absorption. The image display layer has a pattern shape corresponding to at least a part of the images I1a, I2 and I3. This image display layer can be composed of at least one of a dye and a pigment and an arbitrary resin. Such an image display layer can be obtained, for example, by using a thermal transfer recording method using a thermal head, an ink jet recording method, an electrophotographic method, or a combination of two or more thereof. Further, at least a part of the image display layer may be formed by a thermal transfer recording method using a hot stamp, may be formed by a printing method, or may be formed by using a combination thereof.

  This image display layer may not be patterned. That is, the image display layer may be a continuous film. In this case, the image display layer can be obtained, for example, by forming a layer containing a heat-sensitive color former and drawing on this layer with a laser beam.

  This image display layer can be omitted. For example, the image display layer may be provided on the cover body 21 without being a component of the image display body 22.

As shown in FIG. 3, the image display body 22 further includes an image display layer 220 a and a protective layer 227.
The image display layer 220a includes a diffraction structure forming layer 223, a transparent material layer 229, a reflective layer 224, and an adhesive layer 225.

  The diffraction structure forming layer 223 is a transparent layer in which a relief type diffraction grating is provided on one main surface. The diffractive structure forming layer 223 includes first to third parts that illuminate with white light from a specific illumination direction and display different colors when observed from a specific observation direction. The first to third portions are different from each other in at least one of the grating constant of the diffraction grating and the length direction of the groove. The first to third parts display, for example, blue, green, and red.

  In the diffractive structure forming layer 223, portions corresponding to cells C1 to C3 described later are diffractive structure forming portions. Further, in FIG. 3, for easy understanding, the grooves constituting the diffraction grating are drawn as if their length directions are parallel to the Y direction. May not be parallel to the Y direction. For example, the length direction of the groove may be parallel to the X direction.

  Examples of the material of the diffraction structure forming layer 223 include thermoplastic resins such as polyurethane resin, polycarbonate resin, polystyrene resin, and polyvinyl chloride resin, unsaturated polyester resin, melamine resin, epoxy resin, urethane acrylate, urethane methacrylate, and polyol acrylate. Thermosetting resins such as polyol methacrylate, melamine acrylate, melamine methacrylate, triazine acrylate and triazine methacrylate, mixtures thereof, or thermoformable materials having radically polymerizable unsaturated groups can be used. The diffractive structure forming layer 223 may be formed using a photocurable resin. Note that the diffractive structure forming layer 223 obtained using such a transparent resin typically has a refractive index of 1.3 to 1.7 with respect to light having a wavelength of 550 nm.

  The transparent material layer 229 partially covers the main surface on which the diffraction grating of the diffraction structure forming layer 223 is provided. The transparent material layer 229 makes the reflectance smaller in the region covered by the diffraction grating forming layer 223 on the main surface provided with the diffraction grating than in other regions. Typically, the back surface of the surface of the transparent material layer 229 covering the diffractive structure forming layer 223 is a smooth surface or the surface of the diffractive structure forming layer 223 covered by the transparent material layer 229. In comparison, a groove having a smaller depth with respect to the pitch is provided.

  The transparent material layer 229 has a refractive index substantially equal to that of the diffraction structure forming layer 223. For example, the absolute value of the difference between the refractive index of the transparent material layer 229 for light having a wavelength of 550 nm and the refractive index of the diffraction structure forming layer 223 for light having this wavelength is typically 0.1 or less. When the reflective layer 224 is transparent, the absolute value of the difference between the refractive index of the transparent material layer 229 for a certain wavelength in the visible range and the refractive index of the diffractive structure forming layer 223 for this wavelength is the reflection for the previous wavelength. It is smaller than the absolute value of the difference between the refractive index of the layer 224 and the refractive index of the diffractive structure forming layer 223 for this wavelength.

  The transparent material layer 229 is made of, for example, a transparent resin. The transparent material layer 229 is formed, for example, by supplying ink containing a transparent resin onto the diffraction structure forming layer 223 by a printing method such as an inkjet method.

  As this ink, for example, an ink obtained by dissolving a transparent resin in an organic solvent can be used. Examples of this transparent resin include thermoplastic resins such as polyurethane resin, polycarbonate resin, polystyrene resin and polyvinyl chloride resin, unsaturated polyester resin, melamine resin, epoxy resin, urethane acrylate, urethane methacrylate, polyol acrylate, polyol methacrylate, Thermosetting resins such as melamine acrylate, melamine methacrylate, triazine acrylate and triazine methacrylate, or mixtures thereof can be used. As the organic solvent, for example, methyl ethyl ketone, toluene, cyclohexanone, ethyl acetate, THF, ethanol solvent, glycol solvent or ether solvent can be used.

  As this ink, an ink containing water as a solvent or a dispersion medium may be used. For example, as the ink, an ink obtained by dissolving a water-soluble resin such as polyvinyl alcohol (PVA) in water may be used. Alternatively, as this ink, an emulsion containing a transparent resin such as a polyurethane resin and an acrylic resin as dispersed particles, or a latex such as a butadiene-based latex may be used.

  As this ink, an ultraviolet curable ink may be used. As an ultraviolet curable ink, the mixture containing a polymeric compound, a photoinitiator, and arbitrary additives can be used. As the polymerizable compound, for example, an acrylate or methacrylate monomer can be used. As the photopolymerization initiator, for example, a benzophenone-based, benzoin-based, acetophenone-based, or thioxanthone-based initiator can be used. As an arbitrary additive, a solvent and a dispersing agent can be used, for example.

  When the ink jet method is used, the viscosity of the above ink is adjusted in consideration of the suitability of the ink jet print head. For example, the viscosity of the ink is in the range of 1 to 100 mPa · s.

  The reflective layer 224 is formed on the diffraction structure forming layer 223 and the transparent material layer 229. The reflective layer 224 covers at least part of the surface of the diffraction structure forming layer 223 provided with the relief structure and at least part of the transparent material layer 229. The reflective layer 224 may not cover the transparent material layer 229. Although the reflective layer 224 can be omitted, when the reflective layer 224 is provided, the visibility of an image displayed by the diffraction structure is improved.

  As the reflective layer 224, for example, a transparent reflective layer or an opaque reflective layer can be used. Such a reflective layer 224 can be formed by, for example, a vacuum film forming method such as vacuum deposition or sputtering. When the reflective layer 224 includes a resin, the reflective layer 224 may be formed by applying or printing.

  When a transparent reflective layer is used as the reflective layer 224, even when a pattern such as a pattern and characters is arranged on the back side of the reflective layer 224, this can be viewed from the front side of the image display body 22.

  As the transparent reflective layer, for example, a material whose refractive index satisfies the relationship described above for the transparent material layer 229 can be used. The transparent reflective layer may have a single layer structure or a multilayer structure. In the latter case, the transparent reflective layer may be designed so as to repeatedly cause reflection interference.

  As a material of the transparent reflective layer, for example, a transparent dielectric such as zinc sulfide and titanium dioxide can be used. A transparent reflection layer having a single-layer structure made of a transparent dielectric typically has a higher refractive index with respect to light having the above-described wavelength than the diffraction structure forming layer 223 and the transparent material layer 229. A transparent reflective layer having a multilayer structure made of a transparent dielectric typically has a refractive index with respect to light having the above-mentioned wavelength of the closest layer of the diffractive structure forming layer 223, and the refractive index of the diffractive structure forming layer 223 and the transparent material layer 229 is the same. Greater than the refractive index for light of wavelength.

  Alternatively, a metal layer may be used as the transparent reflective layer. As a material for the metal layer, for example, a single metal such as aluminum, tin, copper, silver, gold, and iron, or an alloy thereof can be used. The metal layer is light-shielding when it is thick, but becomes transparent when it is thin. For example, in the case of an aluminum layer having a thickness in the range of 20 to 40 nm, the metallic luster can be observed under certain observation conditions, but the background can be seen through when the observation angle is changed.

  A thicker metal layer can also be used as the transparent reflective layer. For example, a relatively thick metal layer is formed, and a large number of openings having a diameter or width that are difficult to identify with the naked eye are provided. For example, this metal layer is patterned into a halftone dot or a line. Thereby, a transparent reflective layer made of a metal material can be obtained.

  As the material of the opaque metal reflection layer, for example, the materials described above with respect to the metal layer as the transparent reflection layer can be used. The opaque metallic reflective layer is typically not provided with an opening having a diameter or width that is difficult to identify with the naked eye, and has a sufficient thickness to block light.

  A layer containing a transparent resin and particles dispersed therein may be used as the transparent reflective layer or the opaque reflective layer. As the particles, for example, particles made of a metal material such as a single metal and an alloy, or particles made of a transparent dielectric such as a transparent metal oxide and a transparent resin can be used. In the transparent resin, flakes may be dispersed instead of dispersing the particles.

  The adhesive layer 225 is interposed between the reflective layer 224 and the cover body 21. The adhesive layer 225 is made of, for example, a thermoplastic resin.

  Examples of the material of the adhesive layer 225 include urethane resins, butyral resins, polyester resins, polyvinyl chloride resins such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymers, polyurethane resins, epoxy resins, chlorinated polypropylene, and acrylic resins. , Polystyrene, polyvinylbenzene, styrene-butadiene copolymer resin, vinyl resins such as polyvinyl resin obtained from styrene and alkyl methacrylate (wherein the alkyl group has 2 to 6 carbon atoms), rubber materials, or these Mixtures containing two or more can be used.

  For the adhesive layer 225, higher fatty acids such as wax and stearic acid, metal salts and esters thereof, plasticizers, organic fillers made of organic materials such as polytetrafluoroethylene, polyethylene, silicone resins and polyacrylonitrile, and silica, etc. One or more inorganic fillers made of an inorganic material may be added.

  The adhesive layer 225 may be a component of the image display body 22 or may not be a component of the image display body 22. Further, the adhesive layer 225 can be omitted.

  The protective layer 227 covers the image display layer 220a. The protective layer 227 has optical transparency and is typically transparent. The protective layer 227 can be omitted.

  The protective layer 227 is made of, for example, a resin such as a thermoplastic resin, a thermosetting resin, and an ultraviolet ray or an electrosetting resin. When the image display body 22 is affixed to the cover main body 21 using a transfer foil, it is preferable to use a thermoplastic resin from the viewpoint of flexibility and foil breakability.

  Examples of this thermoplastic resin include polyacrylate resin, chlorinated rubber resin, vinyl chloride-vinyl acetate copolymer resin, cellulose resin, chlorinated polypropylene resin, epoxy resin, polyester resin, nitrocellulose resin, A thylene acrylate resin, a polyether resin, a polycarbonate resin, or a mixture thereof can be used. In consideration of foil cutting properties and abrasion resistance, this resin includes waxes such as petroleum waxes and plant waxes, higher fatty acids such as stearic acid, metal salts thereof, esters and silicone oils and other lubricants, polytetrafluoroethylene One or more of an organic filler made of an organic material such as polyethylene, silicone resin and polyacrylonitrile, and an inorganic filler made of an inorganic material such as silica may be added.

  The image display body 22 includes a plurality of cells C1 to C3. The cells C1 to C3 are arranged in the X and Y directions that intersect each other. The cells C1 to C3 adjacent in the X direction are in contact with each other.

  In the example shown in FIGS. 2 and 3, triplets each composed of three cells C1 to C3 arranged in the X direction are arranged in the X and Y directions. These cells C1 to C3 form a stripe arrangement. The cells C1 to C3 may form another arrangement such as a delta arrangement instead of the stripe arrangement.

  The X and Y directions are parallel to the main surface of the cover body 21. The angle formed by the X direction and the Y direction is arbitrary. Here, as an example, it is assumed that the X and Y directions are orthogonal.

  The boundaries of the cells C1 to C3 arranged in the X direction correspond to the boundaries of the first to third portions described above for the diffraction structure forming layer 223. These boundaries are represented by solid lines extending in the Y direction in FIG. The boundary between cells adjacent in the Y direction is determined based on, for example, the arrangement of the transparent material layer 229 shown in FIG. 3, and is represented by a broken line extending in the X direction in FIG.

  Cell C1 typically has the same shape and dimensions. The cell C2 is also typically equal in shape and size. The cell C2 may have the same shape and dimensions as the cell C1, and at least one of them may be different. Further, the cell C3 is also typically equal in shape and size. The cell C3 may have the same shape and dimensions as the cell C1 or C2, and at least one of them may be different. Here, as an example, the cells C1 to C3 have the same shape and dimensions.

  A triplet consisting of three cells C1 to C3 has a small size and typically cannot be distinguished from each other when viewed with the naked eye.

Each of the cells C1 to C3 are either made of a high-efficiency unit P _H, or, and a high-efficiency unit P _H and the low-efficiency unit P _L.

High efficiency unit P _H is a portion where no and transparent material layer 229 comprises a diffractive structure is not provided out of the image display 22. High efficiency unit P _H, when illuminated with white light from a particular illumination direction, and emits a visible light as diffracted light in a specific direction.

On the other hand, the low efficiency part P _L is a part corresponding to the transparent material layer 229 in the image display body 22. For example, the low-efficiency portion P _L does not emit visible light as diffracted light in any direction even when illuminated with white light from any direction. Alternatively, the low-efficiency unit P _L, when illuminated with white light from a particular illumination direction, at low intensity as compared with the high-efficiency unit P _H, emits a visible light as diffracted light in a specific direction.

Next, a method for manufacturing the personal authentication medium 100 will be described with reference to FIGS.
FIG. 4 is a plan view schematically showing an example of a blank medium that can be used for manufacturing the personal authentication medium shown in FIG. FIG. 5 is a cross-sectional view of the blank medium shown in FIG.

  4 and 5 illustrate a transfer foil 201 containing a blank medium. As shown in FIG. 5, the transfer foil 201 includes a transfer material layer 220 a ′ as a blank medium and a support 221 that supports the transfer material layer 220 a detachably.

  The support body 221 is, for example, a resin film or a sheet. The support 221 is made of a material having excellent heat resistance such as polyethylene terephthalate (PET). On the main surface of the support 221 supporting the transfer material layer 220a ', a release layer containing, for example, a fluororesin or a silicone resin may be provided.

  The transfer material layer 220 a ′ includes a protective layer 227 and a diffractive structure forming layer 223. The protective layer 227 and the diffractive structure forming layer 223 are formed on the support 221 in this order.

  The whole or a part of the transfer material layer 220a 'is used for manufacturing the image display layer 220a. The transfer material layer 220a 'or a part thereof is the same as the image display layer 220a except that it does not include the transparent material layer 229, the reflective layer 224, and the adhesive layer 225.

  In manufacturing the personal authentication medium 100, for example, first, a person's face is photographed using an imaging device. Alternatively, a face image is read from the print. Thereby, image information is obtained as electronic information. This face image is subjected to image processing as necessary.

  Next, a transparent material layer 229 and a reflective layer 224 are formed in this order on the transfer foil 201 using, for example, an apparatus 500 shown in FIG. Here, as an example, it is assumed that the transfer foil 201 is a transfer ribbon.

  FIG. 6 is a perspective view schematically showing an example of a manufacturing apparatus that can be used for manufacturing the personal authentication medium shown in FIG. FIG. 7 is a view schematically showing a part of the ink jet print head included in the manufacturing apparatus shown in FIG.

  An apparatus 500 shown in FIG. 6 includes inkjet printing apparatuses 510 and 530, dryers 520 and 540, a thermal transfer printing apparatus 550, a thermal transfer apparatus 560, and a transport mechanism 570.

  The transport mechanism 570 transports the transfer foil 201 in the length direction. The inkjet printer 510, the dryer 520, the inkjet printer 530, the dryer 540, the thermal transfer printer 550, and the thermal transfer device 560 are arranged in this order from the upstream side to the downstream side of the flow of the transfer foil 201.

  As shown in FIG. 7, the ink jet printing apparatus 510 includes a plurality of ink jet nozzles 511. These inkjet nozzles 511 are arranged to face the rows of cells C1 to C3.

  The inkjet nozzle 511 ejects ink droplets 229D toward the diffractive structure forming layer 223 of the transfer foil 201 in order to form the transparent material layer 229. The ejection operation of these inkjet nozzles 511, for example, the timing of ejecting inkjet ink, is individually controlled by a controller (not shown).

  The ink droplet 229D ejected on the diffraction structure forming layer 223 forms an ink layer 229L shown in FIG. The dryer 520 shown in FIG. 6 dries the ink layer 229L. For example, when the ink contains a solvent or a dispersion medium, the dryer 520 dries the ink layer 229L by an evaporation drying method using, for example, far infrared rays and / or hot air. When the ultraviolet curable ink is used, the dryer 520 dries the ink layer 229L by, for example, an ultraviolet drying method. Thereby, the transparent material layer 229 shown in FIG. 3 is obtained.

As shown in FIG. 2, when the area ratio of the transparent material layer 229 to the cell when observed from the Z direction, that is, the area ratio of the low efficiency portion P _L to the cell is different between cells displaying the same color. A gradation image can be displayed. In addition, in addition to blue, green, red, white and black, the area ratio between the low-efficiency portion P _L and this cell is appropriately set in each of the cells C1 to C3 constituting the triplet. It is also possible to display a desired intermediate color.

  The transfer foil 201 moves to the front surface of the ink jet printing apparatus 530 shown in FIG. 6 after passing through the drying process by the dryer 520. The ink jet printing apparatus 530 ejects ink droplets on the diffraction structure forming layer 223 and the transparent material layer 229 in order to form the reflective layer 224. The ink droplets ejected on these form an ink layer.

  The dryer 540 dries the ink layer. For example, when the ink contains a solvent or a dispersion medium, the dryer 540 dries the ink layer by an evaporation drying method using, for example, far infrared rays and / or hot air. Alternatively, when ultraviolet curable ink is used, the dryer 540 dries the ink layer by, for example, an ultraviolet drying method. Thereby, the reflective layer 224 shown in FIG. 3 is obtained.

  The reflective layer 224 may be provided on the diffraction structure forming layer 223 and the transparent material layer 229 using a transfer foil. For example, first, a transfer foil in which a reflective layer and an adhesive layer are formed in this order on a support is prepared. As the reflective layer, for example, a reflective layer including a transparent resin and metal flakes dispersed therein is formed. Next, the laminated body of the reflective layer and the adhesive layer is thermally transferred from the support onto the diffraction structure forming layer 223 and the transparent material layer 229. In this way, the reflective layer 224 is provided on the diffraction structure forming layer 223 and the transparent material layer 229.

  The reflective layer 224 can also be formed by a vacuum film formation method such as vacuum deposition and sputtering. However, when the above-described ink jet recording method or thermal transfer method is used, for example, the reflective layer 224 patterned in a halftone dot or a line shape can be easily formed, and the apparatus 500 can be easily downsized.

  Next, an adhesive layer 225 is formed over the reflective layer 224. The adhesive layer 225 is obtained, for example, by applying a liquid containing a thermoplastic resin on the reflective layer 224 using a coating device (not shown) and drying the coating film with a dryer (not shown).

  Subsequently, the transfer foil 201 on which the adhesive layer 225 is formed moves to the front of the thermal transfer printing apparatus 550. The thermal transfer printing apparatus 550 includes a thermal head 551 and thermally transfers a part of the ink layer of the transfer ribbon 552 from the support onto the adhesive layer 225. Thereby, a printing pattern is formed on the adhesive layer 225 as an image display layer. When the reflective layer 224 is opaque, for example, an opening is provided in the reflective layer 224, and an image display layer as a print pattern is formed at the position of the opening.

  This image display layer is, for example, a layer containing at least one of a coloring material, a fluorescent material, and an infrared absorbing material. This image display layer displays, for example, at least one of the images I1a and I2 shown in FIG. Instead of forming the image display layer by a thermal transfer recording method using a thermal head, for example, an ink jet recording method, an electrophotographic method, a thermal transfer recording method using a hot stamp, a printing method, or a combination thereof is used. Can be formed. As the printing method, for example, an offset printing method, a gravure printing method, a screen printing method, a flexographic printing method, or a relief printing method can be used.

  Note that this image display layer may be positioned between the diffraction structure forming layer 223 and the adhesive layer 225 instead of being formed on the adhesive layer 225. For example, this image display layer may be formed on the reflective layer 224 when the reflective layer 224 is transparent.

  Thereafter, the transfer foil 201 moves to the front of the thermal transfer device 560. The thermal transfer device 560 thermally transfers a part of the transfer material layer 220a 'together with the layer formed thereon from the support 221 to the flip side of the booklet 100'.

  For this thermal transfer, for example, a heat roll or a hot stamp is used. Note that thermal transfer using a thermal head may be performed instead of thermal transfer using a heat roll or a hot stamp. As described above, the image display body 22 is attached to the booklet 100 '.

  For example, an image display layer for displaying the image I3 may be formed on the booklet 100 '. On the other hand, an adhesive anchor layer may be formed in order to increase the adhesive strength.

  In this manner, after the image display body 22 is thermally transferred onto the booklet 100 ', necessary steps are appropriately performed. As described above, the personal authentication medium 100 described with reference to FIGS. 1 to 3 is obtained.

In this method, the low-efficiency portion P _L is formed in the cells C1 to C3 using an ink jet recording method. It is therefore possible to record images on demand on the diffraction grating array. Further, in this method, instead of performing the laser beam irradiation, to form a low-efficiency unit P _L in cells C1 to C3 to form a transparent material layer 229. Therefore, blackening due to laser beam irradiation does not occur. That is, according to this method, an image can be recorded on the diffraction grating array on demand, and an excellent image quality can be achieved.

  The image display 22 displays a part of personal information using a hologram and / or a diffraction grating. It is extremely difficult to tamper with personal information displayed by the hologram and / or diffraction grating, particularly biological information. In the above-described method, the image display body 22 is supported on the cover body 21 by thermal transfer. Such an image display body 22 is easily destroyed when it is peeled off from the cover body 21. Therefore, the personal authentication medium 100 is difficult to falsify.

  In manufacturing the personal authentication medium 100, a blank medium described below may be used instead of the blank medium described with reference to FIGS.

  FIG. 8 is a perspective view schematically showing a modification of the blank medium. FIG. 9 is a perspective view schematically showing another modification of the blank medium. FIG. 10 is a perspective view schematically showing still another modification of the blank medium.

  8 to 10 show a transfer foil 201 containing a blank medium. Similar to the transfer foil 201 described with reference to FIGS. 4 and 5, these transfer foils 201 include a transfer material layer 220 a ′ as a blank medium and a support 221 that supports the transfer material layer 220 a so as to be peeled off. .

The transfer foil 201 shown in FIGS. 8 to 10 is the same as the transfer foil 201 described with reference to FIGS. 4 and 5 except that the protrusion PR is provided between the cells C1 to C3 adjacent in the X direction. It is almost the same. The provision of protrusions PR, the positional accuracy of the ink layer 229L shown in FIG. 7, i.e., the positional accuracy of the low efficiency unit P _L shown in FIG. 2 improves. Specifically, the ink layer 229L to be formed on a certain cell can be prevented from spreading to a cell adjacent to this cell in the X direction.

  The position of the top of the projection PR is higher than the bottom of the groove of the diffraction grating DG provided in the diffraction structure forming layer 223. The height of the protrusion PR with respect to the bottom of the groove of the diffraction grating DG may be lower than the depth of the groove of the diffraction grating DG. Alternatively, as illustrated in FIG. 9, the height of the protrusion PR with respect to the bottom of the groove of the diffraction grating DG may be equal to the depth of the groove of the diffraction grating DG. Alternatively, as shown in FIGS. 8 and 10, the protrusion PR may have a height that is higher than the depth of the groove of the diffraction grating DG, with respect to the bottom of the groove of the diffraction grating DG. From the viewpoint of positional accuracy of the ink layer 229L shown in FIG. 7, it is advantageous that the height of the protrusion PR is high.

  As shown in FIGS. 8 and 9, the protrusions PR may be partitions extending in the Y direction and arranged in the X direction. Alternatively, as shown in FIG. 10, the protrusion PR includes partition walls PR1 that extend in the Y direction and are arranged in the X direction, and convex portions PR2 that are arranged in the Y direction on each partition wall PR1. Also good. In addition, when the viscosity of the ink used for formation of the ink layer 229 shown in FIG. 7 is sufficiently high, the partition part PR1 can be omitted from the protrusion part PR shown in FIG.

Next, the second aspect of the present invention will be described.
FIG. 11 is a cross-sectional view schematically showing a personal authentication medium according to the second aspect of the present invention.

  In the second embodiment, instead of supplying the ink for forming the transparent material layer 229 onto the diffraction structure forming layer 223, a liquid in which the diffraction structure forming layer 223 is dissolved is supplied thereon. In this way, at the position where this liquid is supplied, the surface structure of the diffraction structure forming layer 223 changes as indicated by reference sign DP in FIG. 11, and as a result, the diffraction efficiency of the diffraction grating DG becomes zero or Reduced.

11 corresponds to the low-efficiency part P _L in FIG. The portion is indicated by reference numeral DG in Figure 11 corresponds to the high-efficiency unit P _H of FIG.

  The liquid for dissolving the diffractive structure forming layer 223 is appropriately selected according to the material used for the diffractive structure forming layer 223. This liquid may be water, an aqueous solvent other than water, or an organic solvent as long as the diffraction structure forming layer 223 can be dissolved.

  Moreover, this liquid may contain the component which remains as solid content after drying, if the diffraction structure formation layer 223 can be dissolved. For example, this liquid may further contain a resin.

The blank medium used here may adopt the structure described with reference to FIGS. 4 and 5, or may adopt any of the structures described with reference to FIGS. 8 to 10. In general, the liquid in which the diffractive structure forming layer 223 is dissolved has a smaller viscosity than the ink used to form the transparent material layer 229. Therefore, this liquid tends to spread on the diffractive structure forming layer 223. Thus, while referring to the described structure has been described with particular reference to FIG. 8 structure 8 to 10, is very effective for forming a low-efficiency unit P _L shown in FIG. 2 with high positional accuracy.

  The above-described technique can be used not only for displaying color images but also for displaying monochrome images. Moreover, this technique can be used not only for displaying a planar image but also for displaying a stereoscopic image.

  FIG. 12 is a plan view schematically showing an example of a blank medium that can be used for manufacturing an image display body that displays a stereoscopic image. FIG. 13 is a plan view schematically illustrating another example of a blank medium that can be used for manufacturing an image display body that displays a stereoscopic image.

12 and 13, reference symbols C0 _R and C0 _L represent a right-eye cell and a left-eye cell, respectively. Reference symbol G represents a groove of the diffraction grating.

The blank medium 220a ′ shown in FIGS. 12 and 13 is the same as the blank medium 220a ′ described with reference to FIGS. 4 and 5 except that the cells C0 _R and C0 _L are included instead of the cells C1 to C3. It is the same. Each of the cells C0 _R and C0 _L is, for example, cells C1 to C3 except that the direction of the groove G of the diffraction grating is different or the grating constant of the diffraction grating is different from the direction of the groove G. Has substantially the same structure as any of the above.

In each of the cells C0 _R and C0 _L , the grooves G have the same shape and are arranged in parallel with each other at a constant pitch. In addition, the shape and pitch of the groove G are the same in the cell C0 _R and the cell C0 _L. In the example shown in FIGS. 12 and 13, the groove G is curved in an arc shape, but these grooves may not be curved.

In each of the cells C0 _R and C0 _L , the length direction of the groove G is inclined with respect to the X direction and the Y direction. The cell C0 _R and the cell C0 _L have the same inclination angle in the length direction of the groove G with respect to the X direction and the Y direction, but these length directions are inclined opposite to the X or Y direction.

Under specific diffused light illumination conditions, the diffraction grating emits diffracted light of maximum intensity in a direction perpendicular to the length direction of the groove G. Therefore, when the above structure is adopted, the direction in which the right-eye cell C0 _R emits diffracted light with the maximum intensity may be different from the direction in which the left-eye cell C0 _L emits diffracted light with the maximum intensity. it can. The image display body 22 obtained from the blank medium 220a ′ shown in FIG. 12 and FIG. 13 uses this to display a right-eye image in a cell group including the right-eye cell C0 _R , and the left-eye cell. An image for the left eye is displayed in a cell group consisting of C0 _L.

In the blank medium 220a ′ shown in FIG. 12, one of the two cells adjacent to each right eye cell C0 _R in the X direction is the right eye cell C0 _R , while the other is the left eye cell. Cell C0 _L. Further, the two cells adjacent to each right eye cell C0 _R in the Y direction are both left eye cells C0 _L. Similarly, one of the two cells adjacent to each left-eye cell C0 _L in the X direction is the left-eye cell C0 _L , and the other is the right-eye cell C0 _R. The two cells adjacent to each left eye cell C0 _L in the Y direction are both right eye cells C0 _R. Therefore, when the structure shown in FIG. 12 is adopted, the low efficiency portion P _L shown in FIG. 2 is required to have high positional accuracy in both the X direction and the Y direction.

On the other hand, in the blank medium 220a ′ shown in FIG. 13, each of the two adjacent to the right eye cell C0 _R in the X direction is the left eye cell C0 _L. the two cells that are adjacent in the Y direction with respect to the cell C0 _R both a right-eye cell C0 _R. Similarly, the two cells adjacent to each left-eye cell C0 _L in the X direction are both right-eye cells C0 _R , but adjacent to each left-eye cell C0 _L in the Y direction. The two matching cells are both left eye cells C0 _L. Therefore, when adopting the structure shown in FIG. 13, the low-efficiency portions P _L shown in FIG. 2, as the case of employing the structure shown in FIG. 12, there is no possibility that high positional accuracy is required for the Y direction.

12 and 13 depict a diffraction grating array having a simple structure for the sake of simplicity, but other configurations may be adopted for the diffraction grating array for displaying a stereoscopic image. Is also possible. For example, in the diffraction grating array, in addition to two types of cells C0 _R and C0 _{L in} which the length direction of the groove G has the same inclination angle and is inclined in the opposite direction, cells having different length directions of the groove G are further provided. May be included. Further, the diffraction grating array for displaying a stereoscopic image may adopt a configuration capable of displaying a color image.

  Next, a method for recording a stereoscopic image on the blank medium 220a 'described with reference to FIGS. 12 and 13 will be described. Here, as an example, the blank medium 220a 'shown in FIG. 13 is used.

  FIG. 14 is a diagram schematically illustrating an example of a stereoscopic image capturing method. FIG. 15 is a diagram schematically showing an element image obtained by performing image processing on one of images taken by the method shown in FIG. FIG. 16 is a diagram schematically showing an element image obtained by performing image processing on another image captured by the method shown in FIG.

When shooting a stereoscopic image, for example, as shown in FIG. 14, a plurality of cameras C _R , C _C, and C _L are arranged on the same horizontal plane, and the subject S is captured by these cameras C _R , C _C, and C _L. Shoot at the same time. Alternatively, one camera is moved in a horizontal plane and the subject S is photographed at a plurality of positions.

Next, the image data obtained by this photographing is subjected to image processing. In the blank medium 220a ′ shown in FIG. 13, since the diffraction grating array is constituted by two types of cells C0 _R and C0 _L , only the image data obtained at the two photographing positions is used. For example, to shoot a subject S with the camera C _R and C _L shown in FIG. 14, it processes the image data obtained thereby.

Specifically, from the captured image by the camera C _R, select the region corresponding to the right eye cell C0 _R blank media 220a 'shown in FIG. 13, to obtain an element image I _ER shown in FIG. 15. Further, an area corresponding to the left eye cell C0 _L of the blank medium 220a ′ shown in FIG. 13 is selected from the image taken by the camera C _L to obtain an element image I _EL shown in FIG. By superimposing these element image I _ER and I _EL, obtain a combined image (not shown).

Next, this composite image is recorded on the blank medium 220a ′ shown in FIG. That is, the gradation to be displayed in each of the cells C0 _R and C0 _L of the blank medium 220a ′ is obtained from this synthesized image. This tone is correlated with the area ratio occupied in each cell of the low-efficiency portions P _L shown in FIG. Therefore, by forming the low-efficiency portions P _L on the basis of this gradation, it is possible to record the composite image to a blank medium 220a '.

  Thereafter, the reflective layer 224 and the adhesive layer 225 shown in FIG. 3 are formed as necessary. As described above, the image display body 22 that displays a stereoscopic image is obtained.

FIG. 17 is a perspective view schematically showing a state in which the image display body displays a stereoscopic image.
As described above, when the blank medium 220a ′ shown in FIG. 13 is illuminated under a specific condition, the cell C0 _R and the cell C0 _L emit diffracted light having the maximum intensity in different directions. Thus, the image display body 22 obtained by the method described above, when illuminated obliquely from above with a light source LS for emitting the isotropically light, as shown in FIG. 17, image display 22, the cell C0 _R The element image I _ER recorded in the cell group is displayed so as to be perceived by the observer with the right eye, and the element image I _EL recorded in the cell group consisting of the cell C0 _L is perceived by the observer. To display.

Element image I _ER and I _EL is one each, and image processing the data obtained by photographing by the camera C _R and C _L shown in FIG. 14. Accordingly, an observer who perceives the element images I _ER and I _EL with the right eye and the left eye respectively recognizes the image displayed by the image display body 22 as a stereoscopic image.

  A stereoscopic image has a larger amount of information available for personal authentication than a planar image. Therefore, the personal authentication medium 100 on which the image display body 22 displays a stereoscopic image is different from the personal authentication medium 100 on which the image display body 22 displays a flat image in comparison with the owner of the personal authentication medium 100 and the personal authentication medium 100. It is easy to determine whether or not the person whose personal information is recorded is the same person. In addition, the personal authentication medium 100 on which the image display body 22 displays a stereoscopic image is difficult to counterfeit compared to the personal authentication medium 100 on which the image display body 22 displays a flat image.

  However, as is apparent from the above description, when a stereoscopic image is displayed on the diffraction grating array, it is necessary to record at least two element images on the diffraction grating array. Therefore, when the stereoscopic image is displayed on the diffraction grating array, the brightness of the display image is less than half compared to the case where the planar image is displayed on the diffraction grating array. Therefore, when the image display 22 displays a stereoscopic image, the above determination can be performed without any problem in a sufficiently bright environment, but the determination is difficult in a dark environment.

  As described below, when a configuration in which a combination of a stereoscopic image and a planar image is displayed on the image display body 22, only the planar image is displayed on the image display body 22 without making discrimination in a dark environment difficult. Compared to the case where the configuration for displaying the information is adopted, forgery of the personal authentication medium 100 can be made more difficult.

  FIG. 18 is a plan view schematically illustrating an example of a blank medium that can be used for manufacturing an image display body that displays a combination of a stereoscopic image and a planar image.

  A blank medium 220a 'shown in FIG. 18 includes regions A1 and A2. The area A1 is an area for displaying a planar image. On the other hand, the area A2 is an area for displaying a stereoscopic image. For example, in the region A1, a plurality of cells having the same pitch and length direction of the grooves of the diffraction grating are arranged in the X direction and the Y direction, and the region A2 has the same structure as described with reference to FIG. have.

  Next, a method for recording a stereoscopic image and a planar image on the blank medium 220a 'described with reference to FIG. 18 will be described.

FIG. 19 is a diagram schematically illustrating an example of a method for capturing a stereoscopic image and a planar image. FIG. 20 is a diagram schematically showing one of the images taken by the method shown in FIG. FIG. 21 is a diagram schematically showing another one of the images taken by the method shown in FIG. FIG. 22 is a diagram schematically showing still another one of the images taken by the method shown in FIG. Specifically, the image I _C shown in FIG. 20 is an image taken by the camera C _C shown in FIG. The image I _R shown in image I _L and 22 shown in FIG. 21, respectively, is an image captured by the camera C _L and C _R shown in FIG. 19.

  At the time of recording the stereoscopic image and the planar image on the blank medium 220a ', for example, photographing is performed by the method shown in FIG.

  In the photographing method shown in FIG. 19, a background BG whose depth can be perceived is placed behind the subject S. The imaging method shown in FIG. 19 is the same as the imaging method described with reference to FIG.

Next, the image data obtained by this photographing is subjected to image processing. Specifically, a portion corresponding to the area A1 of the blank medium 220a ′ shown in FIG. 18 is extracted from the image I _C shown in FIG. This extracted portion includes an image of the subject S and is an element image corresponding to a planar image. Further, the image I _R shown in image I _L and 22 shown in FIG. 21, it extracts a portion corresponding to the area A2 of the blank medium 220a 'shown in FIG. 18, these extracted portions, 16 and 15 The element image for the left eye and the element image for the right eye are obtained by the same method as described with reference. Further, the element image corresponding to the planar image, the element image for the left eye, and the element image for the right eye are overlapped to obtain a composite image.

Instead of shooting the subject S and the background BG camera C _L and C _R, the camera C _L and C _R background BG only to the photographing element image and the right eye for the left eye from an image obtained by this Element images may be generated. The composite image can also be obtained by superimposing the element images for the left eye and right eye obtained in this way and the element images corresponding to the previous planar image.

  Next, this composite image is recorded on the blank medium 220a 'shown in FIG. Thereafter, the reflective layer 224 and the adhesive layer 225 shown in FIG. 3 are formed as necessary. The image display body 22 is obtained as described above.

  The image display body 22 displays the subject S as a planar image. Therefore, when the image display body 22 is used in the personal authentication medium 100, the owner of the personal authentication medium 100 and the person whose personal information is recorded on the personal authentication medium 100 are the same person even in a dark environment. It is easy to determine whether or not.

  Further, the image display body 22 displays the background BG as a stereoscopic image. Therefore, the personal authentication medium 100 including the image display body 22 is difficult to counterfeit compared to the personal authentication medium 100 on which the image display body 22 displays only a planar image.

  The personal authentication medium 100 as a passport has been exemplified above, but the technique described above for the personal authentication medium 100 can also be applied to other personal authentication media. For example, this technology can be applied to various cards such as a visa and an ID card. Alternatively, the above-described technique may be used for purposes other than personal authentication.

  The material of the base material to which the image display body 22 is attached may not be paper such as natural paper and synthetic paper. For example, the material of the base material to which the image display 22 is pasted is a synthetic resin such as polyethylene terephthalate resin (thermoplastic PET), polyvinyl chloride resin, thermosetting polyester resin, polycarbonate resin, polymethacrylic resin and polystyrene resin, glass, and the like. It may be ceramics such as ceramics and porcelain, or metal materials such as simple metals and alloys.

  When the substrate is made of a material containing carbon, at least a part of the images I1a, I2 and I3 shown in FIG. 1 may be recorded on the substrate using a laser engraving method. The laser engraving method is a method in which a substrate is irradiated with a laser beam to cause carbonization at an irradiated portion. Carbonization can occur not only on the surface of the substrate but also in the depth. Therefore, if at least a part of the images I1a, I2 and I3 is recorded on the base material using the laser engraving method, it becomes difficult to tamper with the information.

  The image to be displayed on the image display layer 220a 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 on the image display layer 220a may include at least one of non-biological personal information and non-personal information in addition to biometric information, and at least non-biological personal information and non-personal information instead of the biometric information. One may be included.

Examples of the present invention will be described below.
First, the transfer foil 201 shown in FIG. 5 was manufactured. Specifically, a transparent PET film having a thickness of 25 μm was prepared as the support 221. The following coating liquid L1 was applied on the support 221 and the coating film was dried to obtain a protective layer 227 having a thickness of 1.5 μm. Next, the following coating liquid L2 was applied onto the protective layer 227, and this coating film was dried to obtain a transparent resin layer having a thickness of 1.0 μm. Subsequently, a plate having a relief type diffraction grating array provided on the plate surface was hot-pressed on the transparent resin layer at a plate surface temperature of 160 ° C. to transfer the diffraction grating array to the surface of the transparent resin layer. Thereby, the diffraction structure forming layer 223 was obtained.

  Next, the transparent material layer 229, the reflective layer 224, and the adhesive layer 225 shown in FIG. 3 were formed on the transfer foil 201 in this order. Specifically, the transparent material layer 229 was formed by supplying inkjet ink made of an ultraviolet curable resin onto the diffraction structure forming layer 223 by an inkjet method and irradiating the ink layer with ultraviolet rays. The transparent material layer 229 was formed so that the diffraction grating array displayed a face image. The reflective layer 224 was formed by supplying the following inkjet ink L3 onto the diffraction structure forming layer 223 and the transparent material layer 229 by an inkjet method, and irradiating the ink layer with ultraviolet rays. The thickness of the reflective layer 224 was 1.0 μm. The adhesive layer 225 was formed by applying the following coating liquid L4 on the reflective layer 224 and drying the coating film. The film thickness of the adhesive layer 225 was 4.0 μm.

  Further, a colored pattern for displaying the same face image and character string as that displayed on the diffraction grating array was formed on the adhesive layer 225 by thermal transfer using a thermal head. In addition, the coloring pattern formed here contains the layer which consists of a mixture of a pigment and resin.

Thereafter, a part of the transfer material layer 220a ′ was thermally transferred from the support 221 onto the turn of the booklet together with the transparent material layer 229, the reflective layer 224, the adhesive layer 225, and the coloring pattern formed thereon. In this thermal transfer, a heat roll was used and the heating temperature was 125 ° C.
As described above, the personal authentication medium 100 shown in FIG. 1 was completed.

[Composition of coating liquid L1]
Acrylic resin 30 parts by weight Polyester resin 5 parts by weight Polyethylene powder 5 parts by weight Toluene 40 parts by weight Methyl ethyl ketone 40 parts by weight Methyl isobutyl ketone 20 parts by weight [Composition of coating liquid L2]
Polyurethane resin 30 parts by weight Methyl ethyl ketone 70 parts by weight Toluene 30 parts by weight [Composition of inkjet ink L3]
Titanium oxide (nanoparticles / rutile type) 93 parts by weight Photoinitiator 7 parts by weight Polyfunctional monomer (tetraethylene glycol diacrylate) 21 parts by weight Monofunctional monomer (vinyl pyrrolidone) 12 parts by weight Surfactant 0.6 parts by weight Solvent (2-pyrrolidone) 20 parts by weight Water 80 parts by weight [Composition of coating liquid L4]
20 parts by mass of urethane resin 10 parts by mass of butyral resin 60 parts by mass of methyl ethyl ketone 60 parts by mass of toluene

DESCRIPTION OF SYMBOLS 1 ... Signature, 2 ... Cover, 11 ... Paper piece, 12 ... Print pattern, 21 ... Cover body, 22 ... Image display body, 100 ... Personal authentication medium, 100 '... Booklet body, 201 ... Transfer foil, 220a ... Image display Layer, 220a '... transfer material layer, 221 ... support, 223 ... diffraction structure forming layer, 224 ... reflection layer, 225 ... adhesive layer, 227 ... protective layer, 229 ... transparent material layer, 229D ... ink droplet, 229L ... ink 500, manufacturing device, 510 ... inkjet printer, 511 ... inkjet nozzle, 520 ... dryer, 530 ... inkjet printer, 540 ... dryer, 550 ... thermal transfer printer, 551 ... thermal head, 552 ... transfer ribbon, 560 ... transfer systems, 570 ... transfer mechanism, A1 ... area, A2 ... area, BG ... background, C0 _L ... left eye cells, C0 _R ... right eye cell, C1 ... Le, C2 ... cell, C3 ... cell, C _C ... camera, C _L ... camera, C _R ... camera, DG ... surface structure of the diffraction grating, the diffraction structure forming layer in DP ... low efficiency unit, G ... groove, I1a ... image, I1b ... image, I2 ... image, I3 ... image, I _EL ... element image, I _ER ... element image, P _H ... efficient unit, P _L ... low efficiency unit, PR ... projection, PR1 ... partition wall, PR2 ... convex part, S ... subject.

Claims (13)

  A plurality of cells arranged in first and second directions intersecting each other are provided, and each of the plurality of cells is provided with a blank medium including a transparent diffraction structure forming portion provided with a relief-type diffraction grating on the surface. Then, a transparent material layer is formed on a region made of the diffraction grating in the surface of the diffractive structure forming part included in a part of the plurality of cells, or a liquid for dissolving the diffractive structure forming part is supplied And the image display body obtained by making zero or reducing the diffraction efficiency of the said diffraction grating in at least one part of the said area | region.   In the plurality of cells, the diffraction efficiency of the diffraction grating is zero or reduced in at least a part of the region, and the diffraction efficiency of the diffraction grating occupying the region is zero or reduced. The image display body according to claim 1, comprising two or more cells having different proportions.   The image display body according to claim 1, wherein each of the plurality of cells further includes a reflective layer that covers at least a portion of the region where the diffraction efficiency of the diffraction grating is not reduced.   5. The blank medium according to claim 1, wherein the plurality of cells adjacent to each other in the first direction have different lattice constants and / or groove length directions of the diffraction grating. The image display body according to item 1.   The blank medium further includes a plurality of protrusions disposed between adjacent ones of the plurality of cells in the first direction and having a top position higher than a bottom of the groove of the diffraction grating. Item 5. The image display body according to Item 4.   The image display body according to claim 5, wherein the plurality of protrusions are a plurality of partition walls each extending in the second direction and arranged in the first direction.   The image display body according to claim 5, wherein the plurality of protrusions are arranged in the first and second directions.   6. The first and second directions are orthogonal to each other, and adjacent cells in the second direction among the plurality of cells have the same grating constant and groove length direction of the diffraction grating. 8. The image display body according to any one of items 7. A base material for displaying an image including personal information;
A personal authentication medium comprising the image display body according to any one of claims 1 to 8 supported by the base material.   The image displayed by the image display body includes first personal information, the image displayed by the base material includes second personal information, and the first and second personal information are information of the same person. The personal authentication medium described.   The personal authentication medium according to claim 10, wherein at least one of the first and second personal information includes biometric information. Use in the manufacture of an image display comprising a plurality of high efficiency cells each including a diffraction grating and a low efficiency cell in which at least a portion of the diffraction efficiency of each of the diffraction gratings is zeroed or reduced. A blank medium,
Each includes transparent diffraction structure forming portions provided with relief-type diffraction gratings on the surface, arranged in first and second directions intersecting each other, and those adjacent to each other in the first direction are A plurality of cells having different lattice constants and / or groove length directions,
A blank medium comprising a plurality of protrusions disposed between adjacent ones of the plurality of cells in the first direction and having a height higher than that of the region of the surface made of the diffraction grating.   A plurality of cells arranged in first and second directions intersecting each other are provided, and each of the plurality of cells is provided with a blank medium including a transparent diffraction structure forming portion provided with a relief-type diffraction grating on the surface. Then, a transparent material layer is formed on a region made of the diffraction grating in the surface of the diffractive structure forming part included in a part of the plurality of cells, or a liquid for dissolving the diffractive structure forming part is supplied And the manufacturing method of the image display body including making the diffraction efficiency of the said diffraction grating zero or reducing in at least one part of the said area | region.

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