JP5515713B2 - Image display body, transfer foil, and personal authentication medium - Google Patents

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 that a multilayer film is transferred from a transfer ribbon onto a substrate. Further, Patent Document 4 describes that multilayer films having different display colors are juxtaposed in order to display a color image.

  Usually, an image displayed by a multilayer film pattern cannot be reproduced using a generally available transfer ribbon, and can be visually recognized with the naked eye. Further, according to the method of transferring a multilayer film, it is possible to achieve an excellent image quality as compared with the case of using a pearl pigment. This technique is suitable for recording images on demand, and is expected to be applied to recording personal information.

Further, in order to enhance the forgery prevention effect, a stereoscopic image can be expressed using a hologram such as a diffraction grating. Patent Documents 5 and 6 propose a technique for displaying a three-dimensional image with a pattern made of a diffraction grating.
These pixels use cells made of diffraction gratings (with different grating directions) according to the direction in which parallax is given, that is, the direction in which display light (first-order diffracted light) is emitted, and the cells are used in different directions. This is a method for forming a composite image.
As shown in FIG. 16A, for a two-dimensional image obtained by photographing a three-dimensional object serving as a subject from various directions C1 to C4, four types of emitting first-order diffracted light according to each direction C1 to C4. When a composite image is formed using the diffraction grating cell of
As shown in FIG. 16B, a two-dimensional image corresponding to each direction of P1 to P4 (taken from the directions of C1 to C4, respectively) is displayed and reproduced. Since the left eye of P2 (C2) and the right eye of the observer 40 visually recognize the image of P3 (C3), the image is felt with a three-dimensional effect.
If the diffraction grating is a straight line, the emission direction of the first-order diffracted light is limited. Therefore, if a grating made up of a collection of curves is used, it is possible to make the direction spread, and the first-order diffracted light is transmitted between adjacent cells. It is possible to reduce the area that does not emit light.
This prevents the perceived parallax image from being switched when the observer moves the viewpoint in the left-right direction, and contributes to a smooth change in parallax. As a method having a similar configuration and effect, there is a method using a hologram.

  However, when a stereoscopic image is expressed, a diffraction grating cell is provided by dividing it into a plurality of planar images in order to give parallax. For this reason, the luminance is greatly reduced, and the visual effect is drastically reduced. For this reason, as described above, when expressed on paper, unevenness on the paper surface of the transfer surface is picked up, and the luminance of the hologram is remarkably reduced, making it difficult to see, making it difficult to determine authenticity visually. This is because the more two-dimensional images that are prepared, the smoother the stereoscopic image, but the corresponding decrease in luminance is greater.

JP 2000-141863 A JP 2002-226740 A Japanese Patent Laid-Open No. 2003-170685 JP 10-49647 A Kaihei 3-206401 JP-A-5-2148

  The present inventors believe that if an image showing a more complicated visual effect can be displayed with high image quality, the effect of suppressing fraud is further improved. Therefore, the present invention is capable of displaying an image showing a complicated visual effect with high image quality.

The first aspect of the present invention displays a first image as a diffraction image when observed from a first direction under a specific illumination condition, and is different from the first direction under the illumination condition. A relief-type first diffractive structure that does not display the first image as a diffraction image when observed from a direction or displays the first image as a darker diffraction image than when observed from the first direction; ,
When observed from the second direction under the illumination conditions, a second image different from the first image is displayed as a diffraction image, and when observed from the first direction under the illumination conditions Relief-type second diffractive structure that does not display the second image as a diffraction image or displays the second image as a darker diffraction image compared to the case where the second image is observed from the second direction, and a colored image that displays a color image Layers,
Comprising
A first image having a shape corresponding to the first image, wherein the first diffractive structure is provided on one main surface of the colored image layer, the first reflective layer having light transmittance is provided. A display layer;
The second image is provided with the second diffractive structure on one main surface of the colored image layer, and has a second reflective layer having light transmittance, and has a shape corresponding to the second image. Display layer and
Comprising
The first image display layer and the second image display layer are adjacent to each other, and the first image display layer column and the second image display layer column are alternately and repeatedly arranged,
The colored image layer at least partially overlaps the first image display layer and the second image display layer;
It is an image display body which displays a stereoscopic image by the colored image layer and the first and second images as diffraction images .
The second aspect of the present invention displays the first image as a diffraction image when observed from the first direction under specific illumination conditions,
When observed from a second direction different from the first direction under the illumination conditions, the first image is not displayed as a diffraction image or compared with a case where the first image is observed from the first direction. A relief-type first diffractive structure which is displayed as a darker diffraction image,
When observed from the second direction under the illumination conditions, a second image different from the first image is displayed as a diffraction image, and when observed from the first direction under the illumination conditions A relief type second diffractive structure that does not display the second image as a diffracted image or displays the second image as a diffracted image darker than when observed from the second direction;
A colored image layer for displaying a colored image;
Comprising
A first image having a shape corresponding to the first image, wherein the first diffractive structure is provided on one main surface of the colored image layer, the first reflective layer having light transmittance is provided. A display layer;
The second image is provided with the second diffractive structure on one main surface of the colored image layer, and has a second reflective layer having light transmittance, and has a shape corresponding to the second image. A display layer,
The first image display layer and the second image display layer are adjacent to each other, and the first image display layer column and the second image display layer column are alternately and repeatedly arranged,
The colored image layer have at least partially overlapping engagement with the first image display layer and the second image display layer,
It is an image display body which displays a stereoscopic image by the colored image layer and the first and second images as diffraction images .
According to a third aspect of the present invention, the first image display layer is constituted by a plurality of first dot-like portions whose centers are located on lattice points of a virtual planar lattice,
The second image display layer is composed of a plurality of second dot-like portions whose centers are located on lattice points of a virtual planar lattice,
3. The image display body according to claim 1, wherein the plurality of first dot-like portions and the plurality of second dot-like portions are adjacent to each other.
A fourth aspect of the present invention is an image display according to the third aspect, wherein the stereoscopic image includes personal information.
A fifth aspect of the present invention is the image display body according to the fourth aspect, wherein the personal information includes a face image.
A sixth aspect of the present invention is a transfer foil including the image display body according to any one of the first to fifth aspects, and a support body that releasably supports the image display body.
A seventh aspect of the present invention is a personal authentication medium comprising an image display body according to any one of the first to fifth aspects and a base material that supports the image display body.

According to the present invention, an image showing a complicated visual effect can be displayed with high image quality.
The image display according to the first aspect of the present invention includes relief-type first and second diffractive structures. The first diffractive structure displays a first image as a diffraction image when observed from a first direction under a specific illumination condition, and is observed from a second direction different from the first direction under the illumination condition. In this case, the first image is not displayed as a diffraction image, or the first image is displayed as a darker diffraction image as compared with the case where the first image is observed from the first direction. The second diffractive structure displays a second image different from the first image as a diffracted image when observed from the second direction under the previous illumination condition, and is observed from the first direction under the illumination condition. In this case, the second image is not displayed as a diffraction image, or is displayed as a darker diffraction image as compared with the case where the second image is observed from the second direction. Therefore, for example, a three-dimensional image can be displayed on the image display body, or different images can be displayed depending on the observation direction. That is, this image display body shows a complicated visual effect.
Furthermore, by displaying the individual information by partially facing the above-described hologram stereoscopic image and the colored image displayed by the colored image layer, an element called a colored image layer is added compared to the case of only the hologram stereoscopic image. This makes forgery more difficult and increases security.
In addition, by combining a hologram stereoscopic image and a colored image, a full-color hologram stereoscopic image can be expressed in a pseudo manner, and the visibility of individual information is significantly improved compared to a conventional hologram-only image. It can be displayed with image quality. Since it is easy to visually determine the authenticity, the authenticity of the personal authentication medium is improved.
The image display body according to the second aspect of the present invention employs the configuration described above for the image display body according to the first aspect, and the first image display layer is provided on one main surface of the colored image layer. The first diffractive structure is provided, the first reflective layer having light transmittance is provided, and has a shape corresponding to the first image. The second image display layer is provided with a second diffractive structure on one main surface of the colored image layer, includes a second reflective layer having light transmittance, and has a shape corresponding to the second image. Yes.
When this configuration is adopted, when the image display body is observed by an observer, the first image display layer and the second image display layer are laminated on the surface of the colored image layer, and the first image display layer and the second image display layer are laminated. Is arranged on the surface on the viewer side. By using a light transmissive material for the reflective layer, a colored image of the underlying colored image layer can be visually recognized in addition to the stereoscopic image. For this reason, the effect of preventing forgery is improved as compared with the case of only a hologram stereoscopic image, and it becomes possible to make reproduction and tampering even more difficult.
In addition, by combining a hologram stereoscopic image and a colored image, a full-color hologram stereoscopic image can be expressed in a pseudo manner, and the visibility of individual information is significantly improved compared to a conventional hologram-only image. It can be displayed with image quality. Since it is easy to visually determine the authenticity, the authenticity of the personal authentication medium is improved.
For example, an image can be recorded using a transfer foil. Therefore, this configuration is suitable for the process of recording images on demand.
The image display body according to the third aspect of the present invention employs the configuration described above for the image display body according to the first aspect, and the first image display layer is formed on one main surface of the colored image layer. The first reflective layer provided with the first diffractive structure is provided, and has a shape corresponding to the first image. The second image display layer includes a second reflective layer having a second diffractive structure provided on one main surface of the colored image layer, and has a shape corresponding to the second image. A colored image layer for displaying a colored image is provided, and the colored image layer is light transmissive.
When this configuration is adopted, when an image display body is observed from an observer, a colored image layer is laminated on the surface on which the first image display layer and the second image display layer are arranged, and the colored image layer is on the observer side. The structure is arranged on the surface. By using a light-transmitting material for the colored image layer, a stereoscopic image of the underlying hologram layer can be visually recognized in addition to the colored image by the colored image layer. For this reason, the effect of preventing forgery is improved as compared with the case of only a hologram stereoscopic image, and it becomes possible to make reproduction and tampering even more difficult.
Further, when the above-described structure is used, there is no need to limit the amount of reflected diffracted light emitted from the reflective layer, so a variety of materials are used to display a highly visible three-dimensional image with a large amount of reflected diffracted light emitted. It is also possible. For this reason, the effect of preventing forgery is improved as compared with the case of only a hologram stereoscopic image, and it becomes possible to make reproduction and tampering even more difficult.
In addition, by combining a hologram stereoscopic image and a colored image, a full-color hologram stereoscopic image can be expressed in a pseudo manner, and the visibility of individual information is significantly improved compared to a conventional hologram-only image. It can be displayed with image quality. Since it is easy to visually determine the authenticity, the authenticity of the personal authentication medium is improved.
For example, an image can be recorded using a transfer foil. Therefore, this configuration is suitable for the process of recording images on demand.
The image display body according to the fourth aspect of the present invention employs the configuration described above for the image display body according to the second aspect, and the first image display layer has a virtual planar lattice at each center. The second image display layer is composed of a plurality of second dots whose centers are located on the lattice points of a virtual planar lattice. It is comprised by the shape part. The plurality of first dot portions and the plurality of second dot portions overlap at least partially. This configuration is suitable for a process of recording an image by thermal transfer using a thermal head.
The image display according to the fifth aspect of the present invention employs the configuration described above for the image display according to the first aspect, and displays a stereoscopic image by the first and second images as diffraction images. To do. An image display for displaying a stereoscopic image is difficult to counterfeit.
The image display according to the sixth aspect of the present invention employs the configuration described above for the image display according to the fifth aspect, and the stereoscopic image includes personal information. It is extremely difficult to falsify personal information displayed by a stereoscopic image.
The image display body according to the seventh aspect of the present invention employs the configuration described above for the image display body according to the sixth aspect, and the personal information includes a face image. A face image is common as biometric information, and is suitable for visual personal authentication.
The transfer foil according to the eighth aspect of the present invention includes the image display body according to any one of the first to seventh side surfaces, and a support that releasably supports the image display body. When the image display body is transferred from the support of such a transfer foil onto the base material, the surface of the base material is compared with the case where each of the first and second diffractive structures is directly formed on the base material. The influence of unevenness on the image quality can be reduced.
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 seventh aspects. Therefore, this personal authentication medium is difficult to tamper with in addition to displaying an image showing a complicated visual effect with high image quality.

The top view which shows roughly the personal authentication medium which concerns on 1 aspect of this invention. The top view which expands and shows a part of personal authentication medium shown in FIG. Sectional drawing along the II line | wire of the personal authentication medium shown in FIG. The top view which shows schematically the diffraction structure which the image display body of the personal authentication medium shown in FIG.2 and FIG.3 contains. The top view which shows schematically the other diffraction structure which the image display body of the personal authentication medium shown in FIG.2 and FIG.3 contains. The top view which expands and shows a part of personal authentication medium which concerns on a comparative example. Sectional drawing along the II-II line of the personal authentication medium shown in FIG. Sectional drawing which shows schematically an example of the secondary transfer foil which can be used for manufacture of the personal authentication medium shown in FIG. 1 thru | or FIG. The top view which expands and shows a part of personal authentication medium which concerns on one modification. Sectional drawing along the III-III line of the personal authentication medium shown in FIG. Sectional drawing which shows roughly an example of the secondary transfer foil which can be used for manufacture of the personal authentication medium which concerns on the one modification shown in FIG. 1, FIG. 9 thru | or FIG. FIG. 4 is a plan view schematically showing an example of a personal authentication medium according to FIGS. 1 to 3. FIG. 4 is a plan view schematically showing an example of a personal authentication medium according to FIGS. 1 to 3. FIG. 4 is a plan view schematically showing an example of a personal authentication medium according to FIGS. 1 to 3. FIG. 4 is a plan view schematically showing an example of a personal authentication medium according to FIGS. 1 to 3. The schematic diagram which shows typically the method of expressing the stereo image by a prior art.

  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 one 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 incorporate 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 by the cover 2 with the booklet 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 a diffraction structure such as a diffraction grating and a hologram. As will be described in detail later, the image I1b is formed, for example, by performing thermal transfer recording using a thermal head and thermal transfer recording using a hot stamp or a heat roll in this order.

  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. The image I3 may be an image displayed by a diffraction structure such as a diffraction grating and a hologram. When combined with the above image using a known hologram technique, the personal authentication medium 100 can be made more difficult to falsify. A transparent hologram is preferred because the underlying image can be viewed.

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 a cross-sectional view taken along the line II of the personal authentication medium shown in FIG. FIG. 4 is a plan view schematically showing a diffractive structure included in the image display body of the personal authentication medium shown in FIGS. 2 and 3. FIG. 5 is a plan view schematically showing another diffractive structure included in the image display body of the personal authentication medium shown in FIGS. 2 and 3.

  The X direction is a direction parallel to the display surface of the image display body, the Y direction is a direction parallel to the display surface of the image display body and a direction perpendicular to the X direction, and the Z direction is X and X. This is a direction perpendicular to the Y direction. Also, the structure shown in FIGS. 2 and 3 is a portion of the cover 2 corresponding to the image I1b.

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 image display layers 220 a and 220 b, a colored image layer 300, a resin layer 225, and a protective layer 227.

  The image display layer 220a forms a pattern and at least partially overlaps the colored image layer 300. Here, the image display layer 220 a partially overlaps the colored image layer 300 in front of the colored image layer 300.

  The image display layer 220a displays the first image as a diffraction image when observed from the first direction under a specific illumination condition. Then, the image display layer 220a does not display the first image as a diffraction image when viewed from a second direction different from the first direction under the previous illumination conditions, or the first image is displayed as the first image. It is displayed as a darker diffraction image compared to the case of observation from the direction. Here, it is assumed that the first image displayed as the diffraction image by the image display layer 220a is the parallax image for the right eye of the image I1b.

  The image display layer 220a includes a diffraction structure forming layer 223a, a reflective layer 224a, a resin layer 225a, and a protective layer 227a.

  The diffractive structure forming layer 223a has optical transparency, particularly visible light transmission, and is typically a transparent layer. On one main surface of the diffraction structure forming layer 223a, a diffraction grating is provided as a relief type diffraction structure. As shown in FIG. 4, this diffractive structure is composed of a plurality of grooves Ga provided on one main surface of the diffractive structure forming layer 223a. The grooves Ga have the same shape and are arranged in parallel with each other at a constant pitch. The length direction of the groove Ga is inclined counterclockwise with respect to the X direction. In the example shown in FIG. 4, the groove Ga is curved in an arc shape, but the groove Ga may not be curved.

  Examples of the material of the diffractive structure forming layer 223a 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. 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 diffraction structure forming layer 223a may be formed using a resin having photocurability. Note that the diffractive structure forming layer 223a obtained using such a transparent resin typically has a refractive index in the range of 1.3 to 1.7 for light having a wavelength of 550 nm.

The reflective layer 224a is interposed between the cover body 21 and the diffractive structure forming layer 223a. The reflective layer 224a is formed on the diffractive structure forming layer 223a. The reflective layer 224a covers at least part of the surface of the diffraction structure forming layer 223a where the relief structure is provided.
As the reflective layer 224a, for example, a transparent reflective layer or an opaque reflective layer can be used. Such a reflective layer 224a can be formed by, for example, a vacuum film forming method such as vacuum deposition or sputtering. When the reflective layer 224a contains a resin, the reflective layer 224a may be formed by applying or printing.

  In the case of the structure illustrated in FIGS. 2 and 3, the reflective layer 224a is preferably transparent, for example, has light transmittance. When a transparent reflective layer is used as the reflective layer 224a, even if a pattern such as a pattern and characters is arranged on the back side of the reflective layer 224a, it can be visually recognized from the front side of the image display body 22.

  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.

  The transparent reflective layer having a single-layer structure made of a transparent dielectric has a refractive index different from that of the diffraction structure forming layer 223a. Typically, a single-layer transparent reflection layer made of a transparent dielectric has a higher refractive index with respect to light having a wavelength of 550 nm than the diffraction structure forming layer 223a.

  The transparent reflective layer having a multilayer structure made of a transparent dielectric has a refractive index different from that of the diffractive structure forming layer 223a at the portion in contact with the diffractive structure forming layer 223a. The 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 layer closest to the diffractive structure forming layer 223a. Greater than rate.

  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, iron, chromium, nickel and copper, 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.

  Further, by selecting at least one of the above-mentioned materials used for the reflective layer or a combination thereof, it becomes possible to flexibly create an image display body according to the purpose and application, so that the structure is complicated. In addition to this, individual information can be displayed more accurately, finely, and more easily.

The resin layer 225a is formed on the reflective layer 224a. The resin layer 225a can be omitted.
The resin layer 225a is made of, for example, a thermoplastic resin. Examples of the material of the resin layer 225a include urethane resin, butyral resin, polyester resin, polyvinyl chloride resin such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymer, polyurethane resin, epoxy resin, chlorinated polypropylene, and acrylic resin. , Polystyrene, polyvinylbenzene, styrene-butadiene copolymer resin, vinyl resins such as polyvinyl resins obtained from styrene and alkyl methacrylate (wherein the alkyl group has 2 to 6 carbon atoms), rubber-based materials, or these Mixtures containing two or more can be used.

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

The protective layer 227a is interposed between the cover body 21 and the diffractive structure forming layer 223a. The protective layer 227a can be omitted.
The protective layer 227a is made of, for example, a resin such as a thermoplastic resin, a thermosetting resin, and an ultraviolet ray or an electron beam curable resin. When the pattern of the image display layer 220a is formed using the transfer foil, it is preferable to use a thermoplastic resin from the viewpoints 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 layer 220b forms a pattern and at least partially overlaps the colored image layer 300. Here, the image display layer 220 b partially overlaps the colored image layer 300 in front of the colored image layer 300.

  The image display layer 220b displays a second image different from the first image as a diffraction image when observed from the second direction under the illumination conditions described above. Then, the image display layer 220b does not display the second image as a diffraction image when observed from the first direction under this illumination condition, or compared with the case where the second image is observed from the second direction. And displayed as a darker diffraction image. Here, it is assumed that the second image displayed as the diffraction image by the image display layer 220b is the left-eye parallax image of the image I1b.

  The right-eye parallax image and the left-eye parallax image are, for example, images obtained by simultaneously photographing the same subject from different positions. The observer perceives a stereoscopic image by observing the parallax image for the right eye and the parallax image for the left eye with the right eye and the left eye, respectively.

The image display layer 220b includes a diffraction structure forming layer 223b, a reflective layer 224b, a resin layer 225b, and a protective layer 227b.
The diffractive structure forming layer 223b has light transmission properties, particularly visible light transmission properties, and is typically transparent. On one main surface of the diffraction structure forming layer 223b, a diffraction grating is provided as a relief type diffraction structure. As shown in FIG. 5, the diffractive structure includes a plurality of grooves Gb provided on one main surface of the diffractive structure forming layer 223b. The grooves Gb have the same shape and are arranged in parallel with each other at a constant pitch. The length direction of the groove Gb is inclined clockwise with respect to the X direction. In the example shown in FIG. 5, the groove Gb is curved in an arc shape, but the groove Gb may not be curved. As a material of the diffractive structure forming layer 223a, for example, those described above for the diffractive structure forming layer 223a can be used.

  The reflective layer 224b is interposed between the cover body 21 and the diffractive structure forming layer 223b. The reflective layer 224b is formed on the diffraction structure forming layer 223b. The reflective layer 224b covers at least part of the surface of the diffraction structure forming layer 223b where the relief structure is provided.

  The reflective layer 224b is light transmissive. As the reflective layer 224b, for example, the transparent reflective layer described above for the reflective layer 224a can be used.

  The resin layer 225b is formed on the reflective layer 224b. As a material of the resin layer 225b, for example, those described above for the resin layer 225a can be used. The resin layer 225b can be omitted.

  The protective layer 227b is interposed between the cover body 21 and the diffractive structure forming layer 223b. As a material of the protective layer 227b, for example, those described above for the protective layer 227a can be used. The protective layer 227b can be omitted.

  The resin layer 225 covers the cover body 21 and the image display layers 220a and 220b. The resin layer 225 has optical transparency and is typically transparent. The resin layer 225 is made of, for example, a thermoplastic resin. The resin layer 225 can be omitted.

  The protective layer 227 is provided on the resin layer 225. The protective layer 227 has optical transparency and is typically transparent. The protective layer 227 is made of a resin such as acrylic, polyethylene, or polyester.

  The image display layers 220a and 220b are designed to display parallax images having substantially the same brightness. For example, the brightness of the parallax image displayed by the image display layer 220a and the parallax image displayed by the image display layer 220b can be made substantially equal by appropriately setting the reflectance or transmittance of the reflection layers 224a and 224b. .

  As described above, the image display body 22 displays a stereoscopic image as the image I1b. That is, this image display body 22 shows a complicated visual effect.

  The colored image layer 300 uses, for example, a transfer foil using a general ink ribbon material, and a plurality of dots having a small area are transferred by a sublimation transfer method and / or a melt transfer method to provide a color image of individual information. It is displayed. The colored image may be a monochrome image or a color image. In the latter case, the image display layer displaying these images I1a and I2 is formed, for example, by using one or more transfer foils to form, for example, four colored layers of yellow, magenta, cyan and black, or It is obtained by forming colored layers of three colors of red, green and blue.

  It is preferable that the image display layer for displaying the image I2 table can be displayed so as to be a ghost image with a low saturation and a high brightness. This is because if the color saturation is too strong, the image expressed by the second individual information display layer 56 in the upper layer may be canceled. As a rough standard, for example, pale tone, light grayish tone, light tone, soft tone, etc. are appropriate in the Japan Color Co-ordinate System. Further, it is preferable that the chromaticity can be reduced and the brightness can be increased as much as possible with the color scheme used in the image display layer displayed as the image I1a, and the ghost image can be displayed thinly.

  Further, when the configuration described above with respect to the image display body 22 is employed, high resolution can be achieved relatively easily. This will be described with reference to FIGS. 2, 3, 6 and 7. FIG.

  FIG. 6 is an enlarged plan view showing a part of the personal authentication medium according to the comparative example. FIG. 7 is a cross-sectional view of the personal authentication medium shown in FIG. 6 taken along line II-II.

  In the structure shown in FIGS. 6 and 7, the image display layer 220a and the image display layer 220b are juxtaposed without stacking the image display layers 220a and 220b. Specifically, the image display layer 220a and the image display layer 220b are adjacent to each other, and the columns for the image display layer 220a and the columns for the image display layer 220b are alternately and repeatedly arranged in the X direction. A plurality of image display layers 220b are arranged in a row for the image display layer 220a and a row for the image display layer 220b, respectively.

  When this structure is adopted, a stereoscopic image can be displayed, but the viewing angle at which the image can be displayed is narrow, and the image cannot be confirmed depending on the viewing angle of the observer. Further, when the reflective layer provided in the image display layer is light transmissive, not only the above reason but also the reflected diffracted light is reduced, so that it is more difficult to recognize the image.

  On the other hand, when the structure shown in FIGS. 2 and 3 is adopted, a structure in which a colored image layer 300 is added to the structures of FIGS. 6 and 7 is employed. The image display layer 220a and the image display layer 220b are juxtaposed without stacking the image display layers 220a and 220b on the surface of the colored image layer 300. The image display layer 220a and the image display layer 220b are adjacent to each other, and the row for the image display layer 220a and the row for the image display layer 220b are alternately arranged in the X direction, and the image display layer 220a and the image display layer 220b are arranged. A plurality of images are arranged in a row for the image display layer 220a and a row for the image display layer 220b, respectively. The image display layers 220a and 220b are each provided with a reflective layer having optical transparency. Further, the surface having the image display layers 220a and 220b faces the viewer side. Therefore, it can be recognized as a full-color stereoscopic image in a pseudo manner, and an unprecedented visual effect can be given to an observer to achieve high resolution and high visibility. In addition, since the visibility is high, it is easy to determine authenticity by visual inspection. Furthermore, since a colored image is provided, the viewing angle can be widened.

Next, a method for manufacturing the personal authentication medium 100 will be described with reference to FIG.
FIG. 8 is a cross-sectional view schematically showing an example of a secondary transfer foil that can be used for manufacturing the personal authentication medium shown in FIGS. 1 to 3.

  The transfer foil 202 shown in FIG. 8 is a transfer ribbon, for example. The transfer foil 202 includes a support 226 and a transfer material layer 22 ′ that is releasably supported by the support 226.

  The support body 226 is a resin film or a sheet, for example. The support 226 is made of a material having excellent heat resistance such as polyethylene terephthalate. On the main surface supporting the transfer material layer 22 ′ of the support 226, a release layer containing, for example, a fluororesin or a silicone resin may be provided.

  The transfer material layer 22 ′ includes a peeling protection layer 227 ′, a resin layer 225 ′, image display layers 220 a and 220 b, and a colored image layer 300.

  The peeling protective layer 227 'serves to stabilize peeling of the transfer agent layer 22' from the support 226 and to protect the image display layers 220a and 220b from damage. A part or all of the peeling protective layer 227 'is used as the protective layer 227 shown in FIG. In the case where the resin layer 225 'has a function of a release layer, the release protective layer 227' can be omitted.

  The resin layer 225 'is formed on the release protective layer 227'. The resin layer 225 'plays a role of giving sufficient strength to the transfer agent layer 22'. As a material of the resin layer 225 ', for example, a thermosetting resin, a photocurable resin, and a thermoplastic resin can be used. When a thermosetting resin is used, a part or all of the resin layer 225 'can be used as the resin layer 225 shown in FIG.

  A colored image layer 300, an image display layer 220a, and an image display layer 220b are laminated in this order on the resin layer 225 '. Each of the colored image layer 300 and the image display layers 220a and 220b is obtained by, for example, using a thermal head to transfer a part of a transfer material layer releasably supported by a support from a separately prepared transfer foil. It is formed by thermal transfer onto the resin layer 225 ′.

  Since the color image layer 300 and the image display layers 220a and 220b thus obtained are formed by thermal transfer using a thermal head, typically, a plurality of dot-like portions are formed as shown in FIGS. Become. Each center of the dot-like portion constituting the colored image layer 300 is located on a lattice point of a virtual planar lattice. Each center of the dot-like portion constituting the image display layer 220a is located on a lattice point of a virtual planar lattice. Similarly, each center of the dot-like portion constituting the image display layer 220b is located on a lattice point of a virtual planar lattice.

  2 and 3, other grids such as a square grid, a triangular grid, and a rectangular grid may be used for the arrangement of the colored image layer 300. In the plane grid, those grid points are separated from each other. It may be. A high-definition image can be displayed when the interval between the lattice points is short and pixels at each lattice point are adjacent to each other.

  In the arrangement shown in FIG. 2, the previous planar lattice is a square lattice, but the planar lattice may be other lattices such as a triangular lattice and a rectangular lattice. Further, in FIG. 2, a virtual planar lattice in which the center of the dot-shaped portion constituting the image display layer 220a is positioned on the lattice point, and the center of the dot-shaped portion constituting the image display layer 220b. Are the same as the virtual planar grid located on the grid points, but they may be different. For example, the planar grids may have their grid points spaced from each other.

  Moreover, the dot-like part should just be adjacent about each of the image display layers 220a and 220b. For example, in FIG. 2, for each of the image display layers 220a and 220b, adjacent dot-like portions are arranged such that their outlines touch at one point. That is, the diameter of each dot-like part is equal to the minimum center-to-center distance of the dot-like part. Adjacent dot-like portions may be separated from each other. That is, the diameter of each dot-shaped portion may be smaller than the minimum center-to-center distance of the dot-shaped portion. Alternatively, the adjacent dot-like portions may be arranged so as to partially overlap. That is, the diameter of each dot-shaped portion may be larger than the minimum center-to-center distance of the dot-shaped portion.

  The diameter of the dot-shaped portion or the minimum center-to-center distance of the dot-shaped portion is, for example, in the range of 0.042 to 0.508 mm (about 600 to about 50 dots per inch). When displaying face images on the image display layers 220a and 220b, the diameter of the dot-shaped portion or the minimum distance between the centers of the dot-shaped portions is, for example, 0.042 to 0.169 mm (about 600 to about 150 dots per inch). Within the range of When this dimension is increased, it becomes difficult to display high-definition images on the image display layers 220a and 220b. When this dimension is reduced, the reproducibility of the pattern shape of the image display layers 220a and 220b is lowered.

  In addition to the transfer method described above, the transfer foil for the colored image layer and the transfer foil for the image display layer are combined into one roll, and are simultaneously transferred to one layer to display individual information. Also good. In that case, it is necessary to set so that the portion transferred by the dots of the color image layer and the portion transferred by the dots of the hologram layer do not cover.

  An image display layer (not shown) for displaying the images I1a and I2 shown in FIG. 1 is further formed on the resin layer 225 'or between the peeling protective layer 227' and the resin layer 225 '. When the image display layer is formed on the resin layer 225 ′, the image display layer may be formed before the image display layer 220b is formed on the resin layer 225 ′, or the image display layer may be displayed on the resin layer 225 ′. It may be formed after forming the layer 220b and before forming the image display layer 220a, or after forming the image display layer 220a on the resin layer 225 ′.

  When the image display layer for displaying the images I1a and I2 shown in FIG. 1 is formed by a thermal transfer method, a sublimation transfer method may be employed, a melt transfer method may be employed, or both of them may be employed. Good. The images I1a and I2 may be monochrome images or color images. In the latter case, the image display layer that displays the images I1a and I2 is formed, for example, by using one or more ink ribbons to form, for example, four colored layers of yellow, magenta, cyan, and black, or It is obtained by forming colored layers of three colors of red, green and blue.

  A layer (not shown) for displaying the image I3 shown in FIG. 1 may be further formed on the resin layer 225 'or between the release protective layer 227' and the resin layer 225 '. When the layer for displaying the image I3 is formed on the resin layer 225 ′, this layer may be formed before the image display layer 220b is formed on the resin layer 225 ′, or the image display on the resin layer 225 ′. It may be formed after forming the layer 220b and before forming the image display layer 220a, or after forming the image display layer 220a on the resin layer 225 ′. Alternatively, the layer for displaying the image I3 may be formed on the cover body 21 instead of being formed on the resin layer 225 'or between the peeling protection layer 227' and the resin layer 225 '. The layer for displaying the image I3 can be formed, for example, by the same method as described for the image display layer for displaying the images I1a and I2.

  Next, a portion of the transfer material layer 22 ′ formed on the support 226 to be used as the image display body 22 is thermally transferred from the support 226 onto the cover body 21 shown in FIG. 3. For this thermal transfer, for example, a hot stamp is used. Instead of thermal transfer using a hot stamp, thermal transfer using a thermal roll or a thermal head may be performed. The image display body 22 is pasted on the cover body 21 as described above.

  A layer for displaying the image I3 may be formed on the cover body 21 as described above. Further, an adhesive anchor layer may be formed on the cover body 21 in order to increase the adhesive strength.

  When it is difficult to bond the image display body 22 to the cover body 21 with high adhesive strength, a portion of the transfer material layer 22 ′ used as the image display body 22 is transferred onto the cover body 21 through the adhesive layer. Thermal transfer may be performed. For example, an adhesive ribbon may be used. If this is used, the adhesive strength between the image display body 22 and the cover body 21 can be increased. According to this method, a structure in which an adhesive layer is interposed between the image display body 22 and the cover body 21 is obtained.

  When it is difficult to bond the image display body 22 to the cover body 21 with high adhesive strength, and when the image display layer for displaying the images I1a and I2 is formed after the formation of the image display layers 220a and 220b, an adhesive ribbon You may use the ink ribbon which added the function of. This eliminates the need to use an adhesive ribbon separately from the ink ribbon.

  The layers for displaying the images I1a, I2 and I3 shown in FIG. 1 may be provided on the protective layer 227 after the image display 22 is bonded to the cover body 21.

  After the image display body 22 is thermally transferred onto the cover body 21 as described above, necessary steps are appropriately performed. In this way, the personal authentication medium 100 described with reference to FIGS. 1 to 5 is obtained.

  In this method, the color image layer 300 and the image display layers 220a and 220b are formed by thermal transfer using a thermal head. The fineness that can be achieved when using a thermal head is higher than the fineness that can be achieved when printing pearl pigments.

  Further, when the colored image layer 300 and the image display layers 220a and 220b are directly formed on the cover body 21 by thermal transfer using a thermal head, high image quality is achieved due to the surface roughness of the cover body 21 and the like. Is difficult. On the other hand, in the method described above, the colored image layer 300 and the image display layers 220a and 220b are not directly formed on the cover body 21. That is, in this method, first, it is formed on the peeling protection layer 227 ′, and then transferred onto the cover body 21 together with the peeling protection layer 227 ′. Therefore, the surface roughness of the cover body 21 does not have a great influence on the image quality.

  Therefore, according to this method, it is possible to display images with excellent image quality on the colored image layer 300 and the image display layers 220a and 220b.

  The image display 22 displays a part of personal information in combination with a colored image and a stereoscopic image by a hologram and / or a diffraction grating. It is extremely difficult to tamper with personal information, particularly biometric information displayed by a combination of a colored image and a hologram and / or a stereoscopic image by a diffraction grating.

  In addition, a stereoscopic image that has been low in luminance and has been difficult to see visually is also expressed in combination with the colored image by the colored image layer 300, so that it is very easy to see, and the color effect of the colored image by the colored image layer 300 is also combined. It can be recognized as a pseudo full color stereoscopic image.

In this 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.

Various modifications can be made to the image display body 22 described above.
FIG. 9 is an enlarged plan view showing a part of a personal authentication medium according to a modification. 10 is a cross-sectional view of the personal authentication medium shown in FIG. 9 taken along the line III-III.

  In the image display body 22 described with reference to FIGS. 1 to 5, depending on the observation environment, the image display layer 220a and the image display layer 220b are made of a light-transmitting material. It may not be obtained sufficiently, and the image on the image display 22 may appear dark.

  In the structure shown in FIGS. 9 and 10, the colored image layer 300 is arranged on the surface on the viewer side with respect to the surface including the image display layer 220a and the image display layer 220b as viewed from the viewer. ing.

  In the case of the structure shown in FIGS. 9 and 10, the reflective layers of the image display layer 220a and the image display layer 220b may be the above-described reflective layers 224a and 224b. Preferably, a material that can emit a large amount of reflected diffracted light is used. .

  The colored image layer 300 may be made of the above-described materials, but preferably has light transparency. This is for ensuring the visibility of a stereoscopic image by the image display layer 220a and the image display layer 220b.

  Further, in order to ensure the visibility of the stereoscopic image by the underlying image display layer 220a and the image display layer 220b, the colored image layer 300 has a diameter or diameter that is difficult to identify with the naked eye when an opaque material is used. Many openings of width are provided. For example, the colored image layer is patterned into halftone dots or lines.

The effect of this embodiment is basically the same as described above, but a material having a large amount of reflected diffracted light is used for the reflective layers of the image display layer 220a and the image display layer 220b expressing a stereoscopic image. Therefore, the brightness is very high and the visibility is improved. In addition, since the colored image layer 300 is superimposed on the viewer side of the image display layer 220a and the image display layer 220b, the color effect of the colored image layer is combined and recognized as a pseudo full color stereoscopic image. can do.

  2, 3, and 6 to 11, the image display layer 220 a and the image display layer 220 b are provided to display a stereoscopic image using two parallax images. However, different parallax images are used. A structure in which three or more image display layers for displaying a plurality of stereoscopic images are displayed may be employed. That is, a configuration may be adopted in which the appearance of the stereoscopic image changes as if the subject is actually observed by changing the observation angle. By increasing the number of combinations of parallax images, the stereoscopic image of the image display body and the personal authentication medium of the present invention can be expressed with higher definition and smoothness.

  Another example of a configuration in which a plurality of parallax images are combined is shown in FIGS.

  12 to 13, in addition to the combination of the image display layer 220a that is a parallax image for the right eye that perceives the first stereoscopic image on the surface of the colored image layer 300 and the image display layer 220b that is a parallax image for the left eye, A structure is shown in which a combination of an image display layer 220c that is a parallax image for the right eye that perceives a second stereoscopic image and an image display layer 220d that is a parallax image for the left eye is arranged. As a result, two types of stereoscopic images and one type of colored image can be displayed on the image I1b.

  In FIG. 12, the image display layer 220b, the image display layer 220d, the image display layer 220a, and the image display layer 220c are arranged in this order from the left, and each image forming layer is dotted in the horizontal direction (X direction) and the vertical direction (Y direction). It is arranged repeatedly. As described above, even if the image display layers that are parallax images for the left and right eyes that display one stereoscopic image are separated, it is possible to display a plurality of stereoscopic images.

  On the other hand, in FIG. 13, the image display layer 220a and the image display layer 220b are adjacent to each other in the horizontal direction (X-axis direction), and the image display layer 220c and the image display layer 220d are adjacent to each other in the horizontal direction (X-axis direction). It is a structure that is repeatedly arranged in the vertical direction (Y direction). As described above, a plurality of stereoscopic images can be displayed even if the respective image display layers that are parallax images for the left and right eyes displaying one stereoscopic image are adjacent to each other.

  14 to 15, in addition to the combination of the image display layer 220 a that is a parallax image for the right eye that perceives the first stereoscopic image and the image display layer 220 b that is a parallax image for the left eye on the surface of the colored image layer 300. The combination of the image display layer 220c that is a parallax image for the right eye that perceives the second stereoscopic image and the image display layer 220d that is the parallax image for the left eye, and a parallax image for the right eye that perceives the third stereoscopic image. A combination of an image display layer 220e and an image display layer 220f that is a parallax image for the left eye, an image display layer 220g that is a parallax image for the right eye that perceives a fourth stereoscopic image, and an image display layer 220h that is a parallax image for the left eye The combination of each is shown. As a result, four types of stereoscopic images and one type of colored image can be displayed on the image I1b.

  In FIG. 14, an image display layer 220b, an image display layer 220d, and an image display layer 220f for displaying a left-eye parallax image of each stereoscopic image from the left in the horizontal direction (X direction) are arranged. In the figure, these are the left-eye parallax image group L. Also, an image display layer 220h, an image display layer 220a, an image display layer 220c, an image display layer 220e, and an image display layer 220g that display the right-eye parallax image of each stereoscopic image from the left in the horizontal direction (X direction) are arranged in this order. Has been. In the figure, these are the right-eye parallax image group R. The left-eye parallax image group L and the right-eye parallax image group R are adjacent to each other and are repeatedly arranged in the horizontal direction and the vertical direction (Y direction).

  In FIG. 15, the image display layer 220b, the image display layer 220d, and the image display layer 220f that display the parallax image for the left eye of each stereoscopic image are arranged in a matrix in the horizontal direction and the vertical direction. In the figure, these are the left-eye parallax image group L. Further, the image display layer 220h, the image display layer 220a, the image display layer 220c, the image display layer 220e, and the image display layer 220g that display the right-eye parallax image of each stereoscopic image are arranged in a matrix in the horizontal direction and the vertical direction. ing. In the figure, these are the right-eye parallax image group R. The left-eye parallax image group L and the right-eye parallax image group R are adjacent to each other and are repeatedly arranged in the horizontal direction and the vertical direction (Y direction).

  In the configuration of this figure, the distance between the image display layers of the right-eye parallax image and the left-eye parallax image corresponding to displaying a stereoscopic image can be arranged shorter than the configuration of FIG. An image can be displayed and visibility can be secured.

  Note that the arrangement of the image display layers shown in FIGS. 12 to 15 is not necessarily limited, and the left-eye parallax image group L and the right-eye parallax image group R are arranged at positions necessary for displaying an image. It only has to be. The presence or absence of the image display layer in each parallax image group may be adjusted as appropriate according to the purpose and design. The above-described configuration can also be used for the image display bodies shown in FIGS.

  Moreover, you may use secondary transfer foil for manufacture of the personal authentication medium shown to FIG. 12 thru | or FIG. As a method of expressing a three-dimensional image by thermal transfer of a hologram ribbon, for example, a subject is photographed from four directions to prepare four two-dimensional images, and a diffraction grating that emits diffracted light in a direction giving parallax (the grating direction is 4 types of cells made of (different) are prepared, and the cells are used properly in each direction to form the four composite images in two dimensions. Furthermore, a composite image is created on a computer program, the data is output to a thermal transfer device such as a thermal head, and each diffraction grating cell is synthesized using a hologram ribbon composed of four types of diffraction gratings prepared in advance. 3D image can be expressed by thermal transfer method.

  If photographs of a human face possessing a personal authentication medium are taken in advance from a plurality of directions by the above method, individual information can be expressed on the medium as a stereoscopic image on demand by the thermal transfer of the hologram ribbon described above. It becomes possible.

  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.

  The material of the base material to which the image display body 22 is attached may be other than paper. For example, the base material to which the image display body 22 is attached may be a plastic substrate, a metal substrate, a ceramic substrate, or a glass substrate.

  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.

  Instead of displaying stereoscopic images on the image display layers 220a and 220b, different planar images may be displayed on them. In other words, the previous image display 22 may employ a configuration in which the display image is switched according to the observation angle.

Hereinafter, the present invention will be specifically described with reference to examples.

First, an intermediate transfer foil film was prepared. A polyethylene terephthalate film having a thickness of 25 μm was used as a support, and printing was performed with a gravure coater in the order of a release layer and a hologram forming layer. After drying in the oven, the release layer had a thickness of 0.6 μm, and the hologram formation layer had a thickness of 0.7 μm.

This film was hot-pressed with a roll embossing device using a fixed pattern hologram plate to form a fixed pattern hologram on the hologram forming layer.

ZnS was deposited on the fixed pattern hologram forming layer to provide a transparent thin film layer. The film thickness of ZnS vapor deposition was 80 nm. Moreover, the adhesive layer was printed on this film. The film thickness was 0.6 μm.

An intermediate foil was obtained as described above.

  Next, a hologram transfer ribbon was prepared. A polyethylene terephthalate film having a thickness of 12 μm was used as a substrate, and printing was performed with a gravure coater in the order of a release layer and a hologram forming layer. After drying in the oven, the release layer had a thickness of 0.6 μm, and the hologram formation layer had a thickness of 0.7 μm.

This film was hot-pressed with a roll embossing device using a plate in which four types of solid pattern holograms were arranged in the film flow direction to form four types of hologram solid patterns on the hologram forming layer.

ZnS vapor deposition was performed on the hologram forming layer to provide a transparent thin film layer. The film thickness of ZnS vapor deposition was 80 nm. Moreover, the adhesive layer was printed on this film. The film thickness of the adhesive layer was 0.6 μm.

  The film was slit into a transfer ribbon size width, and the films were joined together to form a hologram transfer ribbon.

Further, known yellow, magenta, cyan, and black ink ribbons were prepared.

Using a thermal head, the hologram transfer ribbon was transferred to the target position on the adhesive layer of the intermediate foil to express the 3D face image, and then the ink ribbon was transferred over the 3D face image to express the colored face image. .
It should be noted that a photograph of a face of a person who is the subject in advance is taken from four directions, a composite image is expressed in two dimensions, and a hologram composed of diffraction gratings that emit diffracted light in the direction of parallax is provided as described above. Prepare the type. Then, in the composite image, the position where each diffraction grating cell is transferred is set by a program on a computer, and the stereo image is expressed by outputting it to a thermal head machine.
In addition, the colored face image is expressed with a low color contrast by a conventional method.

Next, an image receiving layer is printed on the entire surface onto which the hologram transfer ribbon or ink ribbon has been transferred, and a face photograph and character information are printed on the image receiving layer with the same ink ribbon. The personal authentication medium of the present invention was obtained by transferring the intermediate foil onto the paper surface as the support.

In the personal authentication medium of the present embodiment configured as described above, the individual information portion is very easy to see visually due to the overlap of the three-dimensional face image and the colored face image, and can be recognized as a pseudo full-color three-dimensional image. It was. It was also found that authenticity can be easily determined by comparing the face photo with the individual information part. For this reason, a personal authentication medium with high security has been completed that can be easily visually checked for authenticity in the event that counterfeit or tampered goods are available.

  Basically, the same as Example 1, but an aluminum vapor deposition layer was provided instead of the transparent vapor deposition of the hologram transfer ribbon. The film thickness was 80 nm.

  In the transfer with the thermal head, the ink ribbon is transferred to the target position on the adhesive layer of the intermediate foil to express the colored face image, and then the hologram transfer ribbon is superimposed on the colored face image and transferred to form the three-dimensional face image. Expressed.

As in Example 1, an image receiving layer is printed on the entire surface onto which the hologram transfer ribbon or ink ribbon has been transferred, and a face photograph and character information are printed on the image receiving layer using the same ink ribbon. The personal authentication medium of the present invention was obtained by transferring the intermediate foil onto the paper surface, which is a support for transfer.

In the personal authentication medium of the present embodiment configured as described above, the individual information portion overlaps the stereoscopic face image and the colored face image, and becomes easier to see than the first embodiment due to the aluminum vapor deposition layer, and is a pseudo full-color stereoscopic image. Could be recognized as. It was also found that authenticity can be easily determined by comparing the face photo with the individual information part. For this reason, a personal authentication medium with high security has been completed that can be easily visually checked for authenticity in the event that counterfeit or tampered goods are available.

  DESCRIPTION OF SYMBOLS 1 ... Signature, 2 ... Cover, 11 ... Paper piece, 21 ... Cover main body, 9 ... Three-dimensional image, 10 ... Image display body, 22 ... Image display body, 22 '... Transfer material layer, 33 ... Diffracted light, 40 ... Observation 100 ... personal authentication medium, 202 ... transfer foil, 220a ... image display layer, 220b ... image display layer, 220c ... image display layer, 220d ... image display layer, 220e ... image display layer, 220f ... image display layer, 220g Image display layer 220h Image display layer 223a Diffraction structure forming layer 223b Diffraction structure forming layer 224a Reflection layer 224b Reflection layer 225 Resin layer 225a Resin layer 225b Resin layer 225 '... resin layer, 226 ... support, 227 ... protective layer, 227' ... peeling protective layer, 227a ... protective layer, 227b ... protective layer, C1-C4 ... camera, Ga ... groove, Gb ... groove, I1a ... image , I1b Image, I2 ... image, I3 ... image, P1~P4 ... viewing zone.

Claims (7)

When observing from the first direction under specific illumination conditions, the first image is displayed as a diffraction image,
When observed from a second direction different from the first direction under the illumination conditions, the first image is not displayed as a diffraction image or compared with a case where the first image is observed from the first direction. A relief-type first diffractive structure which is displayed as a darker diffraction image,
When observed from the second direction under the illumination conditions, a second image different from the first image is displayed as a diffraction image, and when observed from the first direction under the illumination conditions A colored image that displays a relief-type second diffractive structure and a colored image that does not display the second image as a diffracted image or displays a darker diffracted image as compared with the case where the second image is observed from the second direction. Layers,
Comprising
A first image having a shape corresponding to the first image, wherein the first diffractive structure is provided on one main surface of the colored image layer, the first reflective layer having light transmittance is provided. A display layer;
The second image is provided with the second diffractive structure on one main surface of the colored image layer, and has a second reflective layer having light transmittance, and has a shape corresponding to the second image. Display layer and
Comprising
The first image display layer and the second image display layer are adjacent to each other, and the first image display layer column and the second image display layer column are alternately and repeatedly arranged,
The colored image layer at least partially overlaps the first image display layer and the second image display layer;
An image display body that displays a stereoscopic image by the colored image layer and the first and second images as diffraction images . When observing from the first direction under specific illumination conditions, the first image is displayed as a diffraction image,
When observed from a second direction different from the first direction under the illumination conditions, the first image is not displayed as a diffraction image or compared with a case where the first image is observed from the first direction. A relief-type first diffractive structure which is displayed as a darker diffraction image,
When observed from the second direction under the illumination conditions, a second image different from the first image is displayed as a diffraction image, and when observed from the first direction under the illumination conditions A relief type second diffractive structure that does not display the second image as a diffracted image or displays the second image as a diffracted image darker than when observed from the second direction;
A colored image layer for displaying a colored image;
Comprising
A first image display layer comprising a first reflective layer provided with the first diffractive structure on one principal surface of the colored image layer, and having a shape corresponding to the first image;
A second reflective layer provided with the second diffractive structure on one main surface of the colored image layer, and has a shape corresponding to the second image;
Comprising
The first image display layer and the second image display layer are adjacent to each other, and the first image display layer column and the second image display layer column are alternately and repeatedly arranged,
The colored image layer at least partially overlaps the first image display layer and the second image display layer;
An image display body that displays a stereoscopic image by the colored image layer and the first and second images as diffraction images. The first image display layer is composed of a plurality of first dot-like portions whose centers are located on lattice points of a virtual planar lattice,
The second image display layer is composed of a plurality of second dot-like portions whose centers are located on lattice points of a virtual planar lattice,
The image display body according to claim 1, wherein the plurality of first dot-shaped portions and the plurality of second dot-shaped portions are adjacent to each other. The image display body according to claim 3, wherein the stereoscopic image includes personal information. The image display body according to claim 4, wherein the personal information includes a face image. A transfer foil comprising: the image display body according to claim 1; and a support that releasably supports the image display body. The image display body according to any one of claims 1 to 5,
  A base material supporting the image display body;
Personal authentication medium with

Images