JP7326727B2 - Display media and methods for creating display media - Google Patents

Description

TECHNICAL FIELD The present invention relates to display media such as booklets such as passports and visas, cards, and the like, which have images with a high anti-counterfeiting effect, and a method for producing the display media.

Conventionally, various security methods have been proposed for display media such as passports, visa stickers, and cards.

For example, in passports, current passport or ICAO regulations state that they must be readable by both visual and optical character recognition systems. (ICAO stands for International Civil Aviation Organization)
According to ICAO regulations, each country has its own discretion regarding materials and security used in passports. Fibers (silk or synthetic fibers, visible or invisible, fluorescent or non-fluorescent), security threads of films printed with holograms or micro characters, paper with watermarks, fade-resistant inks, fluorescent inks, thermal inks, optical We aim to simultaneously improve security and aesthetics by incorporating various inks such as inks that change into different colors (so-called OVI, etc.), fine line printing, rainbow printing, intaglio printing, pixel printing, and other techniques.

Conventionally, facial photographs used as visual confirmation information in passports were pasted together, but in recent years there has been a trend to digitize photographic information and reproduce this in passports. As a method of reproducing images on passports, there are thermal transfer recording methods using transfer ribbons such as resin type melting type with dispersed pigment, wax melting type, and sublimation type using dye sublimation / diffusion, electrophotography, inkjet. Laws, etc. are being considered.

Display media containing personal authentication data of this type include those in which an image pattern formed based on image data is provided on a base material such as polyvinyl chloride or polycarbonate, or on a paper base material. Further, in addition to the above image pattern, there is known one having a hologram or a diffraction grating.

As a method of forming a hologram or a diffraction grating in addition to an image pattern such as a face photograph in a display medium such as a passport or an ID card containing personal authentication data, there is an image pattern such as a face photograph as shown in Patent Document 1, for example. As the image-receiving sheet on which is formed, an image forming method by an intermediate transfer method using an intermediate transfer film having a hologram layer can be exemplified.

However, in the field of display media containing personal authentication data such as passports and ID cards, new technologies are constantly being sought, and sophistication of design and security is required.

JP-A-6-106740

The present invention has been made in view of the above-described conventional technical problems, and provides a display medium having an unprecedentedly excellent design and high anti-counterfeiting properties, and a method for producing the display medium. for the purpose.

The present invention has been made to solve these problems.
That is, the invention according to claim 1 comprises a relief structure forming layer having an uneven structure on its surface, a metal reflective layer formed so as to cover at least a part of the relief structure forming layer, an image receiving layer, and the image receiving layer. A display medium having at least an image forming part provided in a layer and a support in this order, wherein a visualized pattern region in which the metal reflective layer is provided in parallel lines on at least a part of the metal reflective layer is formed, and at least a visible image area and a latent image area are formed in the image forming unit, and the visible image pattern area and the latent image area are at least one of each other. A visual image is observed through the visual pattern area, and two or more flattened images obtained by compressing the visual image in a specific direction are compressed in the compression direction in the latent image area. A display medium characterized by repeating.

The invention according to claim 2 is the display medium according to claim 1, wherein in the visible image pattern region in which the metal reflective layer is provided in parallel lines, the parallel lines are curved lines. be.

The invention according to claim 3 is the display medium according to claim 1 or 2, wherein the visible image includes at least one or more selected from letters, numerals, and symbols.

(4) In the image forming section, the visible image area and the latent image area are adjacent to each other, or the latent image area is included in at least a part of the visible image area. The display medium according to any one of claims 1 to 3, wherein

(5) The visible image area includes a personal authentication image area, and at least part of the personal authentication image area includes the latent image area. Item 5. The display medium according to any one of Items 4 to 5.

The invention according to claim 6 is the display medium according to claim 5, wherein the information provided in the personal authentication image area is facial photograph information.

The invention according to claim 7 is characterized in that, on an intermediate transfer film substrate, a relief structure forming layer having an uneven structure on its surface, a metal reflective layer formed so as to cover at least a part of the relief structure forming layer, A step of preparing an intermediate transfer film in which an image receiving layer is formed at least in this order; and a step of preparing a thermal transfer sheet in which two or more ink layers containing a dye are sequentially formed on a thermal transfer sheet substrate. The surface of the intermediate transfer film having the image-receiving layer and the surface of the thermal transfer sheet having the ink layer are arranged to face each other, and a thermal head is used to transfer at least the dye to the image-receiving layer so that it is visible. a step of forming an image forming portion comprising an image area and a latent image area; arranging the surface of the intermediate transfer film having the image-receiving layer on which the image is formed and a support so as to face each other; a step of applying heat and pressure from the material side to transfer the relief structure forming layer, the metal reflective layer, and the image receiving layer onto the support, wherein the metal reflective layer has a visual pattern area formed in parallel lines, and a visual image is observed on the image-receiving layer overlapping the visual pattern area when observed through the visual pattern area. A latent image area is formed, and in the latent image area, two or more flattened images obtained by compressing the visible image in a specific direction are repeatedly formed in the compression direction. This is a method of creating a display medium.

According to the invention of claim 8, in the visible image pattern region in which the metal reflective layer is provided in the form of parallel lines, the parallel lines are curved lines. It is the method of creation.

The invention according to claim 9 is characterized in that the visible image is formed so as to include at least one or more selected from letters, numerals and symbols. It is a method of creating a medium.

(10) In the image forming unit, the visible image area and the latent image area are formed adjacent to each other or the latent image area is included in at least a part of the visible image area. 10. The method for producing a display medium according to any one of claims 7 to 9, characterized in that

(11) The visible image area includes a personal authentication image area, and at least part of the personal authentication image area is formed to include the latent image area. A method for producing a display medium according to any one of claims 7 to 10.

The invention according to claim 12 is the display medium creation method according to claim 11, wherein the information provided in the personal authentication image area is facial photograph information.

Identification cards, driver's licenses, passports, various cards, etc. that have moire images with unprecedented design and high anti-counterfeiting properties by using the display medium and the production method of the display medium of the present invention. display medium can be obtained.

1 is a cross-sectional view showing an example of a display medium of the present invention; FIG. 1 is a conceptual diagram showing an example of a printing apparatus for producing a display medium of the invention; FIG. 1 is a cross-sectional view showing an example of an intermediate transfer film of the present invention; FIG. FIG. 3 is a plan view showing an example of a thermal transfer sheet; 1 is a plan view showing an example of a display medium of the present invention; FIG. FIG. 4 is a conceptual diagram showing an example of a flat image according to the present invention; FIG. 2 is a conceptual diagram for explaining the principle of enlarged moire; FIG. 4 is a plan view showing an example of a visible pattern area of the present invention; FIG. 4 is a conceptual diagram showing an example of a line shape of a visual pattern area and a visual image; It is a schematic diagram of a wavy parallel line. FIG. 10 is a schematic diagram for explaining a conventional moire expression;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. Although the drawings will be referred to in the following description as appropriate, the aspects described in the drawings are examples of the present invention, and the present invention is not limited to the aspects described in these drawings.

FIG. 1 is a cross-sectional view showing an example of the display medium of the present invention. In FIG. 1, the display medium (10) comprises a protective layer (11), a relief structure forming layer (12) provided with visible pattern areas (13), latent image areas (15) and visible image areas (16). Each layer of the image receiving layer (14) provided with the image forming section (17) is provided on the surface of the support (18).

(Preparation method of display medium and material composition of medium)
In describing the display medium (10) of the present invention, first, a method for producing the medium and each material constituting the medium will be described.

FIG. 2 is a conceptual diagram showing an example of a printing apparatus for producing the display medium of the present invention.

The printing apparatus (20) has an intermediate transfer film conveying section (21) and a thermal transfer sheet conveying section (22). The thermal transfer sheet (40) unwound from the sheet unwinding section (22a) is placed opposite to the intermediate transfer film (30) using the thermal head (23), and then the thermal roller (25) is printed. ) from the intermediate transfer film (30) to the support (18) to obtain the display medium (10) which is the final printed matter.

As the intermediate transfer film (30) used here, for example, a configuration as shown in FIG. 3 can be exemplified.

The intermediate transfer film (31) comprises a peelable protective layer (32), a relief structure forming layer (12) having an uneven structure on the surface, and a metal layer provided in a pattern on the surface of the intermediate transfer film substrate (31). A reflective layer (34) and a transmissive reflective layer (35) are provided, and an image receiving layer (36) for receiving dyes from a thermal transfer sheet to form an image is laminated.

Examples of the intermediate transfer film substrate (31) include plastic films made of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polypropylene, polyimide, triacetyl cellulose, polyvinyl chloride, poly(meth)acrylic resin, and the like. possible, but not necessarily limited to these.

The protective layer (32) facilitates peeling from the intermediate transfer film substrate (31) as described above, and transfers the protective layer (32) to the support (18) to form a display medium ( 10) has the function of protecting the surface, such as (meth)acrylic resin, melamine resin, polyester resin, chlorinated rubber resin, epoxy resin, polyvinyl chloride and vinyl chloride-vinyl acetate copolymer Examples include vinyl resins such as resins, cellulose resins such as nitrocellulose and triacetyl cellulose, and norbornene resins, but are not necessarily limited to these.

These resins may be used alone or as a composite such as a mixture or laminate of two or more types. , lubricants such as various waxes such as synthetic waxes, fillers such as silica and talc, and the like may be added.

The relief structure forming layer (33) is a layer on which an uneven structure having an optical effect is formed, and a thermoplastic resin, a thermosetting resin, a radiation-curing resin, or the like can be used.

When thermoplastic resins are used, for example, (meth)acrylic resins, epoxy resins, cellulose resins, vinyl resins, mixtures thereof, or copolymers thereof can be used.

When a thermosetting resin is used as the relief structure forming layer (33), for example, a urethane-based resin formed by a cross-linking reaction between a polyol-based resin such as an acrylic-based polyol resin or a polyester-based polyol resin and a polyisocyanate compound. , melamine-based resins, epoxy-based resins, phenol-based resins, mixtures thereof, or copolymers thereof can be used.

Moreover, when using a radiation curable resin, the radiation curable resin typically contains a polymerizable compound and an initiator.

As the polymerizable compound, for example, a compound capable of radical photopolymerization is used. Specifically, a monomer, oligomer or polymer having an ethylenically unsaturated bond or ethylenically unsaturated group can be used. Alternatively, compounds capable of photoradical polymerization include 1,6-hexanediol, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol acrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. , oligomers such as epoxy acrylates, urethane acrylates and polyester acrylates, or polymers such as urethane-modified acrylic resins and epoxy-modified acrylic resins.

When a compound capable of photoradical polymerization is used as the polymerizable compound, a photoradical polymerization initiator can be used as the initiator.

Examples of the photoradical polymerization initiator include benzoin compounds such as benzoin, benzoin methyl ether and benzoin ethyl ether, anthraquinone compounds such as anthraquinone and methylanthraquinone, acetophenone, diethoxyacetophenone, benzophenone, hydroxyacetophenone, 1-hydroxy Cyclohexyl phenyl ketone, α-aminoacetophenone and phenyl ketone compounds such as 2-methyl-1-(4-methylthiophenyl)-2-morifolinopropan-1-one, benzyl dimethyl ketal, thioxanthone, acylphosphine oxide, or , Michler's Ketone, etc. can be used.

Alternatively, a compound capable of cationic photopolymerization may be used as the polymerizable compound. As the compound capable of cationic photopolymerization, for example, a monomer, oligomer or polymer having an epoxy group, a xetane skeleton-containing compound, or vinyl ethers are used.

When a compound capable of cationic photopolymerization is used as the polymerizable compound, a cationic photopolymerization initiator is used as the initiator. As the cationic photopolymerization initiator, for example, an aromatic diazonium salt, an aromatic iodonium salt, an aromatic sulfonium salt, an aromatic phosphonium salt or a mixed-ligand metal salt is used.

Alternatively, a mixture of a compound capable of radical photopolymerization and a compound capable of cationic photopolymerization may be used as the polymerizable compound.

In this case, as the initiator, for example, a mixture of a radical photopolymerization initiator and a cationic photopolymerization initiator is used. Alternatively, in this case, a polymerization initiator that can function as an initiator for both radical photopolymerization and cationic photopolymerization may be used.

Examples of such initiators include aromatic iodonium salts or aromatic sulfonium salts.

In addition, as an example in which a polymerization initiator is not used, a method of inducing a polymerization reaction of a polymerizable compound by electron beam irradiation may be used.

The radiation curable resin includes sensitizing dyes, dyes, pigments, polymerization inhibitors, leveling agents, antifoaming agents, anti-sagging agents, adhesion improvers, coating surface modifiers, plasticizers, nitrogen-containing compounds, epoxy resins, and the like. Additives, mold release agents, or combinations thereof may also be included.

In addition, various resins such as those described above can be used alone or as a mixture. can be used.

When forming an uneven structure on the relief structure forming layer (24) thus obtained, the uneven structure is formed by heating and pressing a press plate made of a metal such as nickel having an uneven pattern. If necessary, it can be formed by irradiating radiation such as ultraviolet rays or electron beams and peeling off the press plate.

The uneven structure includes a flat surface, a matte surface, a diffraction grating structure such as a hologram, a lens structure such as a microlens array or a Fresnel lens, or a plurality of surfaces having different distances from the surface of the relief structure forming layer (33). Concavo-convex structure, one-dimensional grating in which gratings of half the wavelength or more of light are arranged in one direction, and concave-convex structures such as two-dimensional gratings arranged in the direction where two directions intersect each other at wavelengths of light or less can be used, but are not necessarily limited to these.

The plurality of surfaces having different distances from the surface of the relief structure forming layer (33) refer to a specific surface parallel to the plane of the image receiving layer (36) as a reference surface, and have different depths or heights from this surface, And it consists of a plurality of parallel planes, and has the same depth or height with respect to at least one group of reference planes.

By constructing a plurality of planes in this way, it becomes possible to express a specific color depending on the depth or height.

Further, in the case of the one-dimensional grating described above, the diffracted light can be diffracted in one direction according to the direction in which the gratings are arranged, and in the case of the two-dimensional grating described above, light is easily absorbed. .

By arbitrarily arranging such a structure on the surface of the relief structure forming layer (33), it is possible to impart higher designability and security.

As the metal reflective layer (34), for example, a thin film made of a metal such as Al, Sn, Cu, Au, Ag, Cr, Fe, etc., or a scale-like thin film of these metals, or a metal made into fine particles and made into an ink. A high-brightness ink or the like can be exemplified.

Examples of methods for forming a metal thin film include physical vapor deposition methods such as vacuum deposition, sputtering, and ion plating, plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. A chemical vapor deposition method such as a method can be exemplified.

Prior to the formation of the metal reflective layer (34), the surface of the relief structure forming layer (33) may be subjected to surface treatment such as corona treatment, plasma treatment, or ion bombardment treatment.

When using high-brightness ink, it can be formed using conventionally known printing methods such as gravure printing, offset printing, and inkjet printing.

As a method for forming the metal reflective layer (34) made of a metal thin film in a pattern, after forming the metal thin film, a mask is formed in an arbitrary pattern by a conventionally known offset printing method, gravure printing method, screen printing method, or the like. After printing the layer, etching is performed to leave the metal thin film in the portion provided with the mask layer and remove the other portion, thereby forming a patterned metal reflective layer (34). can be formed.

The method of providing the metal reflective layer (34) made of a metal thin film in a pattern is not necessarily limited to these methods. Therefore, a method of removing the metal thin film together with water-soluble ink, a combination of a special relief structure provided in the relief structure forming layer (13) and a dielectric layer provided on the surface of the metal thin film layer, etc. A conventionally known method such as a method that enables etching can be used.

The transmissive reflective layer (35) can be optionally formed as required. As the transmissive reflective layer (35), a dielectric having a refractive index different from that of the relief structure forming layer (33), such as Sb ₂ S ₃ , Fe ₂ O ₃ , TiO ₂ , CdS, CeO ₂ , ZnS, PbCl. ₂ , CdO, _SbO3 , _WO3 , SiO, _Si2O3 , _In2O3 , PbO, _{Ta2O3 ,} ZnO _{, Cd2O3 , Al2O3 , MgF2, etc.} It is also possible to use a transparent thin film or a combination of a plurality of layers of permeable thin films made of these inorganic materials.

Examples of the image-receiving layer (36) include polyester resins such as linear saturated polyesters, vinyl chloride resins such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymer resins, polyacrylic acid, and poly(2-methoxyethyl acrylate). , polymethyl acrylate, poly-2-naphthyl acrylate, polyisobornyl acrylate, polymethacrylomethyl, polyacrylonitrile, polymethyl chloroacrylate, polymethyl methacrylate, polyethyl methacrylate, poly-tert-butyl methacrylate, Acrylic resins such as polyisobutyl methacrylate, polyphenyl methacrylate, copolymer resins of methyl methacrylate and alkyl methacrylate (wherein the alkyl group has 2 to 6 carbon atoms), polystyrene resins, polydivinylbenzene, polyvinylbenzene, Examples include styrene-butadiene copolymer resins, vinyl resins such as styrene and alkyl methacrylate (wherein the alkyl group has 2 to 6 carbon atoms), urethane resins, and epoxy resins, but are limited to these. not a thing Moreover, such resins can be used singly or as a mixture of two or more.

Further, the image receiving layer (36) may contain various additives such as ultraviolet absorbers and fillers without any problem.

Between any of the layers of the intermediate transfer film (30), an ink that absorbs light of a specific wavelength ranging from the ultraviolet region to the infrared region, or an ink that similarly absorbs light of a specific wavelength ranging from the ultraviolet region to the infrared region. Therefore, there is no problem even if a special printing layer or the like printed with ink or the like that emits light in a wavelength region different from the wavelength region absorbed is provided.

FIG. 4 is a plan view showing an example of a thermal transfer sheet (40) for forming an image on the intermediate transfer film (30) as described above.

The thermal transfer sheet (40) comprises a thermal transfer sheet substrate (41) made of a film such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyimide, etc., and a yellow ink layer (Y), a magenta ink layer (M), a cyan ink layer (Y), and a cyan ink layer (41) on the surface of the thermal transfer sheet base material (41). Each color ink layer (42) such as a layer (C) and a black ink layer (Bk) is provided in a frame-sequential manner.

Here, the thermal transfer sheet base material (41) may be subjected to various surface treatments such as antistatic treatment, release treatment, and easy-adhesion treatment on either side, or may be provided with an ink layer (42). There is no problem even if a heat-resistant lubricating layer or the like is provided on the surface opposite to the surface on which it is coated.

In FIG. 4, four color ink layers (42) are shown, but if necessary, three color ink layers excluding the black ink layer, a special color ink layer, a fluorescent ink layer, etc. may be used. , may be further provided.

If the support (18) is not provided with a primer layer or the like for improving adhesion, the thermal transfer sheet (40) may be provided with a primer ink layer.

Either a so-called sublimation ink layer or a melt transfer ink layer can be used for each color ink layer, but the melt transfer ink layer is preferably used in consideration of the durability of the image formed using the ink layer. be able to.

In general, the melt-transfer type ink layer is composed of an ink composition containing at least a coloring material and a binder resin. As the coloring material, any of conventionally known dyes or pigments can be used, but pigments can be preferably used.

Examples of pigments used in the melt transfer ink layer include azo pigments such as phthalimide yellow, benzimidazolone orange, sulfonamide yellow and benzimidazolone yellow, phthalocyanine pigments, diketopyrrolopyrroles, quinophthalones, isoindolinones, Examples include diaminodianthraquinone and carbon black, but are not limited to these.

Any thermoplastic resin can be used as the binder resin. Resins, urethane-based resins, rosin-based derivatives and the like can be mentioned, and these resins can be used alone or as a mixture or a composite such as a copolymer of two or more of them.

In addition, dyes, dispersants, leveling agents, viscosity modifiers, waxes such as vegetable waxes, mineral waxes and synthetic waxes, and fillers such as silica are added to each color ink layer as necessary. There is no problem.

In the case of providing a primer ink layer, a thermoplastic resin can be suitably used, for example, butyral resin, polyamide resin, polyester resin, epoxy resin, acrylic resin, vinyl resin such as vinyl chloride or vinyl acetate, Urethane resins, acrylic-ethylene copolymers, and the like can be used, and these resins may be used alone or as a mixture of two or more.

Fillers such as silica and talc may be added to the primer ink layer, but the amount added is preferably within a range that does not impair the light transmittance of the display medium (10).

Such a primer ink layer may be applied to the support (18) in advance.

In the thermal transfer sheet (40) and the intermediate transfer film (30) obtained as described above, the functional layers, that is, the respective color ink layers (42) and the image receiving layers (36) are arranged facing each other, and the thermal head (23) is applied. ) to form an image forming portion (17) such as a latent image area (15) and a visible image area (16).

Thereafter, a protective layer (32), a relief structure forming layer (33), a metal reflective layer (34), a transmissive reflective layer (35), and an image forming section are applied to the support (18) by a heat roller (25). The display medium (10) is formed by transferring each layer of the image receiving layer (36) having a .

Here, the support (18) is not particularly limited, but conventionally known materials used for booklets such as passports and cards such as ID cards can be arbitrarily used. vinyl resins such as polyvinyl chloride resins, polycarbonate resins, polyolefin resins such as polypropylene, polyester resins such as polyethylene terephthalate, biodegradable resins such as polylactic acid, acrylonitrile-butadiene-styrene copolymer resins , (meth)acrylic resins and other plastic materials can be exemplified, but are not limited to these.

The plastic material as described above may contain, for example, fillers such as titanium oxide, talc, silica and calcium carbonate, and voids such as air bubbles.

Moreover, these materials used for the support (18) may be used alone, or may be used as a mixture or a laminate of two or more layers without any problem.

Further, any layer of the support (18) may be formed with various printed layers or the like without any problem.

(Display medium)
FIG. 5 shows a plan view of an example of the display medium (10) formed as described above.

The display medium (10) has a visible image area such as a personal identification image area (51) containing facial photograph information (52) and a character information area (54) formed using a thermal transfer sheet (40).

However, the image formed by the thermal transfer sheet (40) is not necessarily limited to these, and a design image or the like may be formed for the purpose of design.

In addition, a latent image area (15) is formed using a thermal transfer sheet (40) in the personal authentication image area (51) containing face photograph information (52). ) is provided with a visual pattern area (13) formed by a metal reflective layer (34).

A visible image (53) is observed by observing the latent image area (15) through the visible image pattern area (13).

Here, the visible image pattern area (13) has the metal reflective layer (34) described above formed in parallel lines, and the latent image area (15) has a visible image (53) An image containing at least one or more selected from letters, numerals, and symbols visually recognized as , is formed so as to repeatedly contain two or more flat images compressed in a specific direction.

FIG. 6 shows an example of a flat image (60) obtained by vertically compressing an image visually recognized as a visible image (53).

Divided regions (61) obtained by dividing this flat image (60) with an arbitrary pitch width (d) are, for example, divided regions (a), divided regions (b), and divided regions (c), respectively. A visual image (53) obtained by enlarging a flat image (60) as a moire image is visually recognized by observing through a visual pattern area (13) formed in a line shape with a width. becomes possible.

FIG. 7 is a conceptual diagram for explaining the principle of enlarged moire.

A flat image (60) provided in the latent image area (15) has divided areas (a, b, c) each having an arbitrary pitch width (d). It shows how the number of pitches is divided into three.

The latent image area (15) is overlaid with a visible image pattern area (13) having line widths substantially equal to each other, and observation is carried out. FIG. 7 exemplifies a case where the number of pitches of the line-like visualized pattern area (13) is two.

By superimposing the latent image area (15) and the visible pattern area (13) as described above, one of the divided areas (a, b, c) in the flat image (60) becomes A region that is obscured by parallel lines and becomes difficult to observe is generated.

Therefore, by providing a plurality of flat images (60) that can be divided by the same pitch width (d), the visible image (53) to be observed is a plurality of flat images that can be observed in the space area of parallel lines. It is formed by a combination of sub-regions (a,b,c) of the image (60).

Therefore, the visible image (53) is recognized as an enlarged moire image obtained by enlarging the flat image (60).

At this time, the number of pitches of the observed visible image (53), that is, the image size can be defined by the following formula (1).

In FIG. 7, the visible image (53) is shown in an upside down state with respect to the flat image (60). This phenomenon occurs when the area (13), that is, the pitch number of the parallel lines is small, and the flat image (60) is not necessarily inverted upside down depending on the setting of the pitch number of the parallel lines.

Here, the height (D1) of the flat image (60) provided in the latent image area (15) is preferably difficult to visually recognize, and is less than 1 mm, more preferably about 500 μm or less. desirable.

In the present invention, the latent image area (15) is formed by a thermal transfer method using the thermal head (23). In order to obtain a visible image (53) that can be recognized as a be able to.

On the other hand, the line width and space width of the parallel lines provided in the visualized pattern area (13) can be set arbitrarily, but the line width and space width are preferably about 20 μm or more and 300 μm or less. Considering that the latent image area (15) is formed by the thermal head (23), it is desirable that the line width and space width are approximately 40 μm or more and 250 μm or less.

Also, the line width and the space width may both have the same value, or may be designed with different values.

The height (D2) of the visual image (53) is expressed by the number of pitches of the flat image (60) and the number of pitches of the visual pattern area (13), as shown in equation (1). The pitch number of (53) is determined, and the height (D2) of the visible image (53) is determined by the set pitch width (d). It can be said that the height (D2) of the visual image (53) is determined according to D1) and the values of the line width and space width of the parallel lines provided in the visual image pattern area (13).

Also, the width of a single image (for example, one character) of the flat image (60) is not particularly limited, but it is desirable that it is visible when viewed as a visible image (53). It can be about the above.

The parallel lines provided in the visual pattern area (13) as described above may be straight lines, but may be curved lines as shown in FIG. 8, for example.

In FIG. 9, the parallel lines provided in the visible image pattern area (13) are observed in the case of the straight line (I) and the curve (II) with respect to the same latent image area (15). It conceptually shows how the visible image (53) changes.

As can be seen from FIG. 9, the parallel lines provided in the visible image pattern area (13) can be formed without particularly changing the flat image (60) forming method of the latent image area (15) formed by the thermal head (23). By changing it, it is possible to change the form of the observed visible image (53).

That is, when the flat image (60) provided in the latent image area (15) is formed as a constant repeating pattern, if the parallel lines provided in the visible image pattern area (13) are straight lines (I) , the visible image (53) is also observed as a linear array image.

On the other hand, when the lines provided in the visualized pattern area (13) are curved lines (II), the visualized image (53) is also observed as a curvilinear image along the curves of the lines. It is possible to do so, and various ideas can be devised in terms of the design of the displayed image, and in terms of security, the difficulty of counterfeiting is improved, which is preferable.

Although such curved lines (II) are not particularly limited in shape, for example, a wavy line (70) as shown in FIG. 10 can be exemplified.

When provided as wavy lines (70), the height of the amplitude (Am) is not particularly limited, but for example, the flat image (60 ) is preferably equal to or less than the height (D1) of ).

By making the amplitude (Am) of the wavy lines (70) equal to or less than the height (D1) of the flat image (60), it is possible to visually recognize the visible image (53) without discomfort. It becomes possible.

Further, when such curvilinear parallel lines are microscopically observed, there is no problem even if at least a part thereof is formed in a stepped shape.

FIG. 11 schematically shows image formation by conventional parallel line moire. In the conventional image forming method using parallel lines moire, printed images (
80) and a verification tool (81) consisting of straight lines, and by superimposing these and observing them, a visible image is observed.

However, in this method, a slight positional misalignment between the printed image (80) and the verification tool (81) causes, for example, a positive visible image (Ip), a negative visible image (In), an indistinguishable visible image, and so on. An image image (NG) can be viewed.

Therefore, when a printed image (80) is to be formed using a thermal head, a stable visible image cannot be obtained unless printing is performed while performing precise alignment with the verification tool (81). difficult to obtain.

On the other hand, in the display medium and the display medium production method of the present invention, when the flat image (60) formed in the latent image area (15) is formed using the thermal head (23), the visible image is formed. By changing the visual pattern area (13) without requiring precise alignment with the image pattern area (13), an arbitrary visual image (53) can be expressed, resulting in high designability. It is possible to provide a display medium that is difficult to forge.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the examples below do not limit the scope of the present invention.

Further, in the following examples, the contents described as "parts" are based on mass unless otherwise specified.

(Creation of thermal transfer sheet)
First, an ink layer coating liquid having the following composition was prepared.

<Coating solution for cyan ink layer>
Pigment: Phthalocyanine blue 7 parts Resin: Epoxy resin 20 parts Dye: C.I. I. Solvent Blue 63 2 parts Colorless fine particles: Silica 4 parts Solvent: Methyl ethyl ketone 67 parts

The ink layer coating liquid having the above composition was coated on a 4.5 μm-thick polyethylene terephthalate film having a heat-resistant lubricating layer on the back surface and dried to a dry film thickness of 0.7 μm to form a thermal transfer sheet. Obtained.

(Example 1)
(1) Preparation of Intermediate Transfer Film First, an intermediate transfer film having a protective layer, a relief structure forming layer, a patterned metal reflective layer, and an image receiving layer was prepared on the surface of the intermediate transfer film substrate. .

A polyethylene terephthalate film having a thickness of 25 μm was used as the intermediate transfer film substrate.

As the protective layer, a protective layer coating solution having the following composition was formed on the entire surface of the intermediate transfer film substrate by gravure coating. The thickness of the protective layer after drying is 1.5 μm.

<Coating solution for protective layer>
Acrylic resin 30 parts Toluene 40 parts Methyl ethyl ketone 40 parts Methyl isobutyl ketone 20 parts

The relief structure-forming layer was formed by applying a relief structure-forming layer coating liquid having the following composition to the entire surface of the protective layer by gravure coating. The thickness of the relief structure forming layer after drying was 2.0 μm.

After the relief structure forming layer is formed by printing, a nickel stamper having surface irregularities such as hologram interference fringes and diffraction gratings is used to apply heat and pressure to the surface of the relief structure forming layer. Although the concave-convex structure can be formed, the formation of the concave-convex structure was omitted in this experiment.

<Coating solution for relief structure forming layer>
Mixture of vinyl chloride-vinyl acetate copolymer and urethane resin 25 parts Methyl ethyl ketone 70 parts Toluene 30 parts

The metal reflective layer is formed by vacuum-depositing aluminum (Al) on the entire surface of the relief structure to a film thickness of about 400 Å. , a line pattern mask layer having a line width of 230 μm and a space width of 100 μm was formed by printing, and immersed in an alkaline etching solution to remove the aluminum in the area where the mask layer was not formed to form a visualized pattern area. .

<Coating solution for mask layer>
Vinyl chloride-vinyl acetate copolymer 25 parts Methyl ethyl ketone 70 parts Toluene 30 parts

The image-receiving layer was formed by applying an image-receiving layer coating liquid having the following composition to the entire surface of the relief structure-forming layer having a visible image pattern region composed of a metal reflective layer formed in a pattern by gravure coating. The thickness of the image receiving layer after drying is 2.0 μm.

<Coating liquid for image receiving layer>
Polyester resin 40 parts Vinyl chloride-vinyl acetate copolymer 5 parts Methyl ethyl ketone 40 parts Toluene 40 parts

(2) Formation of the latent image pattern area The previously prepared thermal transfer sheet is printed with a thermal head with a resolution of 600 dpi on the area overlapping the visible image pattern area on the surface of the image receiving layer of the intermediate transfer film obtained as described above. , a flat latent image area with a height (D1) of 360 μm, a latent image area with a flat image with a height (D1) of 400 μm, and a flat image with a height (D1) of 440 μm. A latent image area consisting of an image was formed, respectively.

(3) Preparation of display medium Next, using paper as a support, a primer layer made of urethane resin emulsion is applied to the surface of the paper, and then an intermediate transfer film having a flat image formed thereon is superimposed and heated and pressed with a hot roller. ,
A display medium sample 1 was obtained by peeling off the intermediate transfer film substrate of the intermediate transfer film.

(Example 2)
A display medium sample 2 was obtained in the same manner as in Example 1, except that the mask layer formed on the surface of the metal reflective layer had a parallel line pattern with a line width of 250 μm and a space width of 80 μm.

(Example 3)
A display medium sample 3 was obtained in the same manner as in Example 1, except that the mask layer formed on the surface of the metal reflective layer had a parallel line pattern with a line width of 260 μm and a space width of 100 μm.

(Evaluation of display medium)
For each of the display medium samples 1 to 3 obtained in Examples 1 to 3, the latent image area was observed through the visible image pattern area, and the height (D2) of the observed visible image was measured. was measured. Each evaluation result is shown in Table 1.

From the comparison between Example 1 and Example 2, when the pitch of the parallel line pattern is the same, the height (D2) of the visualized image is also the same, but the narrower the space width, the clearer the image can be obtained. It turned out to be easy.

Further, by comparing Example 1 and Example 3, it is possible to change the height (D2) of the visualized image by controlling the pitch of the parallel line pattern, that is, the line width and the space width. understood.

From the above results, by using the display medium and the method for producing the display medium of the present invention, it is possible to provide a display medium having excellent design and high anti-counterfeiting property, which has never been seen before.

DESCRIPTION OF SYMBOLS 10... Display medium 11, 32... Protective layer 12, 33... Relief structure forming layer 13... Visible pattern area 14, 36... Image receiving layer 15... Latent image area 16... Visible image area 17... Image forming part 18... Support body 20... Printing apparatus 21... Intermediate transfer film conveying unit 21a... Intermediate transfer film unwinding unit 21b... Intermediate transfer film winding unit 22... Thermal transfer sheet conveying unit 22a... Thermal transfer sheet unwinding unit 22b... Thermal transfer sheet winding unit 23... Thermal Head 24... Platen roller 25... Heat roller 30... Intermediate transfer film 31... Intermediate transfer film substrate 34... Metal reflective layer 35... Transmissive reflective layer 40... Thermal transfer sheet 41... Thermal transfer sheet substrate 42... Ink layer 51... Personal authentication Image area 52 Face photo information 53 Visible image 54 Character information area 60 Flat image 61, a, b, c Divided area 70 Wavy lines 80 Printed image 81 Verification tool Am Amplitude d Pitch Width D1... Height of flat image D2... Height of visible image Y... Yellow ink layer M... Magenta ink layer C... Cyan ink layer Bk... Black ink layer Ip... Positive visible image In... Negative visible image NG … Indistinguishable visual image

Claims (12)

a relief structure-forming layer having an uneven structure on its surface; a metal reflective layer formed so as to cover at least a portion of the relief structure-forming layer; an image receiving layer; A display medium having at least a body in this order,
At least a part of the metal reflective layer is formed with a visible pattern region in which the metal reflective layer is arranged in parallel lines,
The concave-convex structure has a surface on the relief structure forming layer that is parallel to the plane of the image receiving layer as a reference plane, and has a different depth or height from the reference plane and is parallel to the reference plane. , wherein at least one group of said faces has the same depth or height with respect to the reference plane,
At least a visible image area and a latent image area are formed in the image forming unit, and the visible pattern area and the latent image area overlap each other at least partially,
In the visible image pattern area where the metal reflective layer is provided in the form of lines, the lines are provided as wavy lines, and the height of the amplitude is the height of the flat image provided in the latent image area. is equal to or less than
A visual image is observed through the visual pattern area,
A display medium characterized in that, in the latent image area, two or more flattened images obtained by compressing the visible image in a specific direction are repeatedly included in the compression direction. 2. A display medium according to claim 1, wherein in said visible image pattern region in which said metal reflective layer is provided in parallel lines, said parallel lines are curved lines. 3. The display medium according to claim 1, wherein the visible image includes at least one or more selected from letters, numerals and symbols. 3. In said image forming section, said visible image area and said latent image area are adjacent to each other, or said latent image area is included in at least part of said visible image area. The display medium according to any one of 5. A display according to any one of claims 1 to 4, wherein said visible image area includes a personal identification image area, and at least part of said personal identification image area includes said latent image area. medium. 6. The display medium according to claim 5, wherein the information provided in the personal authentication image area is facial photograph information. A relief structure forming layer having an uneven surface structure, a metal reflective layer formed so as to cover at least part of the relief structure forming layer, and an image receiving layer are formed at least in this order on an intermediate transfer film substrate. preparing an intermediate transfer film formed by
A step of preparing a thermal transfer sheet comprising two or more ink layers containing pigments formed in a frame-sequential manner on a thermal transfer sheet substrate;
The surface of the intermediate transfer film having the image-receiving layer and the surface of the thermal transfer sheet having the ink layer are arranged to face each other, and a thermal head is used to transfer at least the dye to the image-receiving layer to form a visible image area. forming an image forming portion comprising a latent image area;
The surface of the intermediate transfer film having the image-receiving layer on which an image is formed and a support are arranged to face each other, and heat and pressure are applied from the intermediate transfer film substrate side to form the relief structure-forming layer and the metal reflective layer. and transferring the image-receiving layer onto the support, comprising:
The metal reflective layer has a visual pattern area formed in parallel lines,
In the visible image pattern area where the metal reflective layer is provided in the form of lines, the lines are provided as wavy lines, and the height of the amplitude is the height of the flat image provided in the latent image area. is equal to or less than
the concave-convex structure comprises a plurality of planes parallel to a reference plane, a specific plane parallel to the plane of the image-receiving layer, and at least one group of planes having the same depth or height with respect to the reference plane;
Forming the latent image area in which a visible image is observed when observed through the visible pattern area on the image-receiving layer overlapping the visible pattern area,
A method of producing a display medium, wherein two or more flattened images obtained by compressing the visible image in a specific direction are repeatedly formed in the latent image area in the compression direction. 8. The method of producing a display medium according to claim 7, wherein in the visible image pattern region in which the metal reflective layer is provided in parallel lines, the parallel lines are curved lines. 9. The method of creating a display medium according to claim 7, wherein the visible image is formed so as to include at least one or more selected from letters, numerals and symbols. 3. The image forming section forms the visible image area and the latent image area so that the visible image area and the latent image area are adjacent to each other, or the latent image area is included in at least a part of the visible image area. A method for producing a display medium according to any one of claims 7 to 9. 11. Any one of claims 7 to 10, wherein the visible image area includes a personal authentication image area, and at least part of the personal authentication image area is formed to include the latent image area. A method for producing a display medium according to any one of the above. 12. The method of creating a display medium according to claim 11, wherein the information provided in the personal authentication image area is facial photograph information.

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