JP3536413B2 - Invisible information recording sticker - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a multilayer vapor-deposited laminate whose color sequentially changes depending on the viewing angle, or a transparent hologram image, and is applied to various articles such as goods requiring anti-counterfeiting. The present invention relates to a seal having a function as a certificate and having an anti-counterfeiting effect, and more particularly to a seal for recording invisible information capable of recording invisible information in a non-contact state by a laser or the like.

[0002]

2. Description of the Related Art Recently, multilayer vapor-deposited laminates in which the color sequentially changes depending on the viewing angle have been used in various fields. This multilayer vapor-deposited laminate is obtained by repeatedly vapor-depositing ceramic materials having different refractive indexes with a controlled film thickness, and brings a unique visual effect.

These are also used as a transfer foil or as a seal by slightly changing the structure. There are various configurations for this seal, and as an example,
The multilayer vapor-deposited laminate is provided on one surface of the base material, and the adhesive layer is provided on the other surface of the base material. In addition, it may be difficult to understand the color change when the transparent film is used as it is, and a dark-colored base such as black is often added as a base.

On the other hand, in recent years, transparent hologram transfer foils have been
It has been used in various fields. This transparent hologram transfer foil is formed by sequentially laminating a peeling layer, a hologram forming layer, a transparent thin film layer, and an adhesive layer on a base material as a support, and the transfer body and the transfer foil are almost transparent. The holographic image floats in the air and brings a unique visual effect. In addition to being used as a transfer foil, these are also used as a seal by slightly changing the structure. The seal may have various configurations, and as an example, a hologram forming layer, a transparent thin film layer, and a protective layer are provided on one surface of the base material, and an adhesive layer is provided on the other surface of the base material. Has been.

However, these transparent hologram transfer foils or hologram seals have an anti-counterfeiting effect by themselves because a very advanced technique is required to form their unique hologram image. is doing. Therefore, it usually has no security function other than the hologram transfer foil itself.

On the other hand, in the case of a normal reflection type hologram which is not a transparent hologram, attention is paid to the fact that the hologram image itself records optical interference fringes, and a method of utilizing the interference fringes itself as recorded information has been proposed. ing. The principle of reading this recorded information is that since the diffraction angle of light is related by the wavelength and the spatial frequency of the diffraction grating, a diffraction grating of a certain target spatial frequency is provided in a part of the hologram image, and the diffracted light By detecting
It becomes possible to read the information.

However, since this information recording must be performed at the same time as the production of the hologram image, only the same information can be recorded in the hologram of the same image. Alternatively, the images may be visually similar and the diffraction grating for recording may be changed, but it is still impossible to have different information.

Further, the visibility of the transparent hologram image is inferior to that of the case where the ordinary reflective thin film is provided, and although it is a unique image, it is easy or difficult to see depending on the viewing angle of the hologram. Therefore, the application is limited.

By the way, various techniques have already been proposed as techniques for changing recorded information for each medium, and mainly thermal recording using a thermal head and optical recording using light are widely used. .

For example, as an example of thermal recording, a method of melting a metal thin film layer by heat of a thermal head, a method of coloring a thermal recording layer made of a thermosensitive coloring material typified by a leuco compound by the heat of a thermal head, and the like. It is known and has recently been used as a method of recording balance information and the like in prepaid cards and the like.
These are usually used as means for recording visible information such as characters and images, and a thermal head is generally used as a heat source for recording.

The problem with such a recording medium is that the layer thickness on the thermosensitive recording layer cannot be increased. In practice, for example, the protective layer on the recording surface should be set to a thickness of several μm, and this limitation limits the layer structure on the heat-sensitive recording layer. That is, for example, JP-A-62-1
As described in Japanese Patent No. 278084, when a concealing layer is provided on a thermosensitive recording layer to record / read the recorded information in an invisible state, or when a concealing layer is further provided below the protective layer, the recorded information is recorded. Even if it is tried to make it invisible, the thickness of the hiding layer is limited, so that it is not possible to provide sufficient hiding power.

Also, since the protective layer cannot be made thick, scratches due to contact between the thermal head and the surface of the protective layer are conspicuous,
There is also a problem that the concealment of the recorded information itself is impaired.
This becomes a problem especially when the recorded information is highly confidential.

From the above, a multilayer vapor deposition laminate,
Alternatively, the transparent hologram image has a problem that it is difficult to change the record information for each individual by itself, and further, the visual effect such as color change is low, or the visibility of the hologram image is low, while the variable information is recorded. It can be seen that it is difficult to record invisible information on the thermosensitive recording medium as a technique.

If variable information for each individual can be recorded on the multilayer vapor-deposited laminate or the transparent hologram, it can be used for various purposes. As an example, security and information recording are required at the same time, and a sticker or tag attached to an expensive product can be considered as an important application in which it is important not to spoil the aesthetics of the product.

Up to now, there has been a multilayer vapor-deposited laminate or a seal using a transparent hologram, but it is not possible to record variable information at the same time, and the security is merely due to the visual effect of color change, or simply the hologram image. It only retains the security of information and the difficulty of manufacturing it. In addition, it is possible to make not only visual judgment but also authenticity judgment by a verifier as long as the multilayer vapor-deposited laminated body or a recording medium in which aesthetics of hologram image and recording of variable information are compatible with each other. Therefore, advantages such as higher security can be obtained.

[0016]

As described above, in the conventional multilayer vapor-deposited laminate or the seal further provided with the hologram image, the multilayer vapor-deposited laminate or the aesthetics of the hologram image and the recording of the variable information are provided. There was a problem that it was difficult to achieve both.

The present invention has been made to solve the above problems and is provided with a transparent hologram image,
It is attached to articles such as various products that require anti-counterfeiting, has a forgery-preventing effect with a function as a certificate, does not impair the aesthetics of the transparent hologram image, and is integrated with the transparent hologram image. It is a first object to provide an invisible information recording sticker capable of recording invisible information in a form.

Further, the present invention has been made to solve the above-mentioned problems, and is provided with a multilayer vapor-deposited laminate whose color changes depending on the viewing angle, or a hologram image, and requires forgery prevention. A multi-layer vapor-deposited laminate, which is attached to articles such as various products, has a forgery prevention effect having a function as a certificate, and does not impair the aesthetics of a multi-layer vapor-deposited laminate or a transparent hologram image, Another object is to provide an invisible information recording sticker capable of recording invisible information in a form integrated with a transparent hologram image.

[0019]

In order to achieve the above object, first, the invisible information recording sticker of the invention according to claim 1 is at least (this "at least") on the adhesive layer .
The meaning is that it absorbs in the near infrared region of the recording wavelength and
Absorption in does not matter. ) An infrared absorption layer that exhibits absorption in the near infrared region of the recording wavelength, a thermal recording layer, at least
(This "at least" means that light in the visible region is absorbed.
And transmits near-infrared rays of recording wavelength and reading wavelength.
However, it means that other wavelength ranges are irrelevant. ) A concealing layer that absorbs light in the visible region and transmits in the near-infrared region of the recording wavelength and the reading wavelength, and has different refractive indices (
The meaning of the term "
And that the materials of the layers have different refractive indices.
Is the meaning. ) A multilayer vapor deposition layer, which is formed by laminating a plurality of materials and whose color changes depending on the viewing angle, is sequentially laminated, and between the infrared absorption layer and the adhesive layer, between the heat-sensitive recording layer and the hiding layer, or the hiding layer. Between any of the multiple vapor-deposited layers (this
The meaning of "difference" is (1) between the infrared absorption layer and the adhesive layer
Between (2) the heat-sensitive recording layer and the hiding layer, and (3) the hiding layer.
(1) or (2) or between the multilayer vapor deposition layer
It means (3). ) An invisible information recording sticker, characterized in that a base material is provided between layers.

[0020]

The invisible information recording sticker of the invention according to claim 3 has at least (this " at least
Also means "absorption in the near infrared region of the recording wavelength and other
This means that absorption in the wavelength range is irrelevant. ) An infrared absorption layer that exhibits absorption in the near-infrared region of the recording wavelength, a heat-sensitive recording layer, and at least (this "at least" means that light in the visible region is absorbed
And transmits near-infrared rays of recording wavelength and reading wavelength.
However, it means that other wavelength ranges are irrelevant. ) Light in the visible region is absorbed, hiding layer which transmits near-infrared region of the recording wavelength and the reading wavelength, the hologram formation layer for forming a holographic image, a refractive index different (this "different
The meaning of the term "
And that the materials of the layers have different refractive indices.
Is the meaning. ) A multilayer vapor deposition layer, which is formed by laminating a plurality of materials and whose color changes depending on the viewing angle, is sequentially laminated, and between the infrared absorption layer and the adhesive layer, between the heat-sensitive recording layer and the hiding layer, or the hiding layer. One of the (
“Any” means (1) infrared absorption layer and adhesive layer
Between (2) the heat-sensitive recording layer and the hiding layer, (3) hiding
(1) or (2) or between the layer and the multilayer vapor deposition layer
It means (3). ) An invisible information recording sticker, characterized in that a base material is provided between layers.

[0022]

Further, in claim 2 , at least light in the visible region is absorbed, the near-infrared region of the recording wavelength and the reading wavelength is transmitted, and a hologram formation concealing layer formed by forming a hologram image is provided. Characterize.

[0024] Further, in any one of claims 1 to 3 , the heat sensitive recording layer and the infrared absorbing layer are laminated in this order on the adhesive layer.

Further, in the first to third aspects, the infrared absorption layer has a spectrum that absorbs a specific wavelength in the near infrared region.

In the first to third aspects, the heat-sensitive recording layer is characterized in that the color-developing portion has absorption in a wavelength region different from the specific wavelength in the near infrared region absorbed by the infrared absorption layer.

In the first to third aspects, the multi-layer vapor deposition layer is formed by laminating a plurality of ceramic materials having different refractive indexes.

[0028]

Therefore, first, in the invisible information recording sticker of the invention according to claim 1, when attached to an article such as a product, an image is formed by the colored opaque concealing layer provided in the lower layer of the multilayer vapor deposition laminate. Visibility is improved. Further, the lower infrared absorption layer functions as a photothermal conversion layer to convert infrared rays into heat, and this heat causes the lower thermosensitive recording layer to develop color. This recorded information can be read by utilizing the difference in reflectance between the colored portion and the uncolored portion of the thermosensitive coloring layer.

[0029]

As described above, the invisible information recording sticker of the present invention is provided with the multilayer vapor-deposited laminate whose color changes depending on the visual angle and is attached to various articles such as goods requiring anti-counterfeiting and the certificate. It becomes possible to record invisible information in the form of a multilayer vapor-deposited laminated body seal having an anti-counterfeiting effect, which does not impair the aesthetics of the multi-layer vapor-deposited laminated body and is integrated with the multi-layer vapor-deposited laminated body. .

In addition, the invisible information recording sticker of the invention according to claim 2 has the same function and effect as the invisible information recording sticker of the invention according to claim 1, and additionally has a function as a certificate. The hologram sticker having the anti-counterfeiting effect can be integrated with the transparent hologram image without impairing the aesthetics of the transparent hologram image.

[0032]

Further, the invisible information recording sticker of the invention according to claim 3 has the same operation and effect as the invisible information recording sticker of the invention according to claim 2 , and in addition, simplifies the manufacturing process. be able to.

As described above, the invisible information recording sticker of the present invention is provided with the multilayer vapor-deposited layer whose color changes depending on the viewing angle and the transparent hologram, and is attached to various articles such as goods requiring anti-counterfeiting. It has an anti-counterfeiting effect that functions as a certificate, and records invisible information in a form integrated with the multilayer vapor deposition layer and the transparent hologram image without impairing the aesthetics of the multilayer vapor deposition laminate and the transparent hologram image. Is possible.

On the other hand, in the invisible information recording seal of the invention according to any one of claims 1 to 3 , the infrared absorption layer has an absorption (spectrum) at a specific wavelength in the near infrared region, so that the recording wavelength However, forgery and tampering can be difficult.

In the invisible information recording sticker of the invention according to any one of claims 1 to 3 , the heat-sensitive recording layer comprises:
The colored portion has an absorption (spectrum) in a wavelength region different from the specific wavelength in the near infrared region absorbed by the infrared absorption layer, so that not only the light source for recording information but also the recorded information The reading wavelength is limited, and forgery and tampering can be made even more difficult.

[0037]

Embodiments of the present invention will now be described in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a sectional view showing an example of the arrangement of an invisible information recording sticker according to the first embodiment of the present invention.

The invisible information recording sticker 1 of this embodiment shown in FIG. 1 has an infrared absorbent 4, a heat-sensitive recording layer 5, a hiding layer 6, a multilayer vapor deposition layer 7 and a protective layer 8 in this order on one side of a substrate 3. While being laminated, the adhesive layer 2 is provided on the other surface of the base material 3.

The substrate 3 is preferably a transparent or opaque polyethylene terephthalate film.
In addition to these, materials such as polyvinyl chloride, polyester, polycarbonate, polymethylmethacrylate, and synthetic resins such as polystyrene, natural resins, paper, synthetic paper, glass, etc. may be used alone or as a composite. However, as described later in the reading principle, the optical characteristics are limited depending on the layer structure.

Further, the infrared absorption layer 4 needs to exhibit absorption at least in the wavelength region of the recording wavelength 15, and a layer which transmits in other infrared wavelength regions may be selected depending on the stacking position. . The infrared absorbing layer 4 absorbs the laser light, converts it into heat, and causes the heat-sensitive recording layer 5 laminated by the heat generated to develop color. Generally, a material obtained by mixing a dye or the like having a large absorption coefficient at the laser light wavelength used in a resin is used as a light absorption heat conversion material.

Examples of the light absorption / heat conversion material include polymethine dyes such as cyanine-based, pyrylium-based, thiopyrylium-based, squarylium-based, croconium-based, and azurenium-based dyes, phthalocyanine-based dyes, naphthalocyanine-based dyes, and dithiol metal complex salt-based dyes. , Naphthoquinone dye,
In addition to organic dyes such as anthraquinone dyes, triphenylmethane dyes, aluminum dyes, and diimmonium dyes, metal oxides, metal hydroxides, inorganic pigments such as heat ray absorbing glass powder, and carbon black (however, , A heat-sensitive recording layer) can be used.

The above-mentioned light absorbing heat converting material is mixed with a resin or the like, and the infrared absorbing layer 4 is formed by a known printing means or coating means such as an offset printing method and a gravure printing method.
For example, in the offset printing method, the infrared absorbing ink obtained by kneading, dissolving or dispersing the light absorbing and heat converting material in a transparent medium which does not absorb light in the near infrared region by a three-roll roll or the like is a wet offset printing method or a dry offset printing method. The infrared absorption layer 4 is formed by coating by each means such as. In the gravure printing method, vinyl chloride-vinyl acetate copolymer resin, saturated polyester, polyurethane elastomer, etc. are used as the resin (binder), and additives such as antifoaming agents can be added. Further, as a solvent used for diluting the infrared absorbing ink to an appropriate viscosity, for example, toluene, methyl isobutyl ketone, xylene, cyclohexanol, isobutyl acetate, cyclohexanone, methylcyclohexanone, glycol derivatives such as ethylene glycol monobutyl ether, and the like, Alternatively, a mixed solvent thereof may be used.

The heat-sensitive recording layer 5 is composed of at least an infrared absorbing leuco dye, a developer and a binder. The leuco dye exhibits absorption in the infrared region at the time of color development, and examples thereof include a fluorane compound, a fluorene compound, a phthalide derivative, and the like, and particularly when the thermal recording layer is located on the infrared incident side of the infrared absorbing layer. At least the colored portion or the uncolored portion has absorption (spectrum) in a wavelength region different from the specific wavelength in the near infrared region of the infrared absorption layer. Color developing agents that act on the infrared absorbing leuco dye to develop color include acidic substances such as phenol, cresol, and hydroquinone.
Resin, these are dispersed in a binder of a polymer material such as an ink vehicle, the binder is soluble in water or an organic solvent, specifically, polyvinyl alcohol, methyl cellulose, ethyl cellulose, cellulose acetate, polystyrene, poly Vinyl chloride, linear saturated polyester, homopolymers or copolymers of methacrylic resins such as polymethylmethacrylate and polyethylmethacrylate,
Thermoplastic resins such as polyurethane, polybutyral, and nitrocellulose can be used. If necessary, a dispersant, a defoaming agent, a thickener, etc. can be added as an additive. A coating solution obtained by uniformly dispersing or dissolving the above infrared absorbing leuco dye, developer, binder or the like in water or an organic solvent, a printing method such as a gravure method, an offset method, a screen method, a roll coating method, a gravure coating. Method, a lip coating method, a comma coating method, a die coating method, a micro gravure coating method, a curtain coating method and the like.

The concealing layer 6 is a layer for visually concealing changes below this layer, and absorbs at least in the visible region, while in the infrared region, particularly at the recording wavelength and the reading wavelength for the thermosensitive recording layer 5. , A material that can be regarded as optically transparent or almost transparent.

That is, the concealing layer 6 transmits infrared rays that can be read by an infrared sensor, and
It refers to a material that absorbs visible light to the extent that the recorded image recorded on the heat-sensitive recording layer 5 cannot be identified with the naked eye, and that the infrared transmittance is higher than the visible light transmittance, and the sensitivity of the infrared sensor is Because of its superiority, even if the infrared ray transmittance is lower than the visible ray transmittance, it is sufficient if the recorded image cannot be discriminated by the naked eye and can be discriminated by the infrared sensor.

Typical materials include, for example, a gelatin film, a coating material containing an infrared permeable dye such as Orazole Black BV or Orazole 2RG, a yellow ink, a red ink,
It is possible to use black or gray inks made by mixing printing inks that do not absorb in the infrared region, such as indigo inks. These are known by gravure printing, screen printing, offset printing, etc. The coating method can be used.

Further, the multilayer vapor-deposited layer 7 is required to sequentially change its color depending on the viewing angle, and a plurality of ceramic materials having different refractive indexes are laminated. For example, a high refractive index of about 2 or more is used. A material and a low refractive index material having a refractive index of about 1.5 are laminated in a predetermined film thickness (preferably, the refractive index is “high” “low” “high” “low” “high” in order of 5).
Layers).

Examples of the high refractive index material include Sb ₂ O ₃
(3.0 = refractive index n: same below), Fe ₂ O ₃ (2.
7), TiO ₂ (2.6), CdS (2.6), CeO
₂ (2.3), ZnS (2.3), PbCl ₂ (2.
3), CdO (2.2), Sb ₂ O ₃ (2.0), WO ₃
(2.0), SiO (2.0), Si ₂ O ₃ (2.
5), In ₂ O ₃ (2.0), PbO (2.6), Ta
₂ O ₃ (2.4), ZnO (2.1), ZrO ₂ (2.
0) and the like can be used.

As the low refractive index material, for example, Mg
O (1.6), SiO ₂ (1.5), MgF ₂ (1.
4), CeF ₃ (1.6), CaF ₂ (1.3-1.
4), AlF ₃ (1.6), Al ₂ O ₃ (1.6) and the like can be used.

Then, at least one of these high-refractive index materials and at least one of the low-refractive index materials are respectively selected and laminated alternately with a predetermined thickness to prevent visible light of a specific wavelength. Those that exhibit absorption or reflection can be obtained.

Furthermore, the protective layer 8 plays a role of protecting the lower layer.

For example, acrylic resin, urethane resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin,
Based on conventionally known synthetic resins such as melamine resin, epoxy resin, polystyrene resin, or natural resin, as a material for improving the resistance, a curing agent such as isocyanate, waxes such as polyethylene wax and carnauba wax, or Extenders such as calcium carbonate, silica and alumina, and fats and oils such as silicone fats and oils can be added and used within a range not impairing transparency.

On the other hand, as the adhesive layer 2, for example, an acrylic type adhesive agent, a butyl rubber type adhesive agent, a natural rubber type adhesive agent, a silicone type adhesive agent, a polyisobutyl type adhesive agent alone, or an alkyl methacrylate, vinyl ester, acrylonitrile, styrene,
Aggregating components such as vinyl monomers, unsaturated carboxylic acids, hydroxyl group-containing monomers, modifying components typified by acrylonitrile, and additives such as polymerization initiators, plasticizers, curing agents, curing accelerators, antioxidants, etc. It is possible to add and use it as needed.

Next, in the invisible information recording sticker 1 of the present embodiment configured as described above, when it is attached to an article such as a product by the adhesive layer 2, it is provided as the lower layer of the multilayer vapor deposition layer 7. The colored and opaque hiding layer 6 improves the visibility of the image. Further, there is an infrared absorption layer 4 in the lower layer, and this infrared absorption layer 4 functions as a photothermal conversion layer to convert infrared rays into heat, and this heat causes the thermosensitive recording layer 5 above it to develop color, This colored portion absorbs infrared rays and the uncolored portion transmits infrared rays. Further, the recording information can be read by utilizing the difference in reflectance (absorption rate) between the colored portion and the uncolored portion of the thermosensitive recording layer 5.

Next, an example of the information recording method and the information reading method of the variable information recording sticker 1 of this embodiment will be described.

First, for recording information on the variable information recording sticker 1, as shown in FIG. 2, when a light beam (for example, a laser beam) 11 having an absorption wavelength of the infrared absorption layer 4 is irradiated, photothermal conversion of the infrared absorption layer 4 is performed. Due to the action, heat is generated 12, which causes the heat-sensitive recording layer 5 to develop a color to form an information recording portion 13.
Information is read by utilizing the difference in reflectance between the colored portion and the uncolored portion of the thermosensitive recording layer 5, that is, the contrast between the recorded portion 13 and the unrecorded portion.

FIG. 3 is a conceptual diagram showing the reflection spectra of the colored portion and the uncolored portion of the infrared absorbing layer 4 and the thermosensitive recording layer 5. In the figure, 14 is the reflection spectrum of the infrared absorption layer, 15
Is a colored portion (a) and a non-colored portion (b) of the thermal recording layer 5, 1
6 is the recording wavelength on the invisible information recording seal of the present invention, 17
Is the reading wavelength of the record of the invisible information recording sticker of the present invention. Although the recording wavelength 16 in FIG. 3 is around 830 nm and the reading wavelength 17 is 940 nm, the reflection spectrum 14 of the infrared absorption layer 4 does not affect the reading wavelength 17 and the reflection spectrum of the thermosensitive recording layer 5 is not affected. It suffices that the wavelength range is such that the contrast between the (a) colored portion and the (b) non-colored portion of 15 can be obtained, and the selection of the recording wavelength 16 and the reading wavelength 17 is not limited to these, and the above-mentioned specific The wavelength is determined by the combination of the materials forming the infrared absorption layer 4 and the thermal recording layer 5.

As described above, in the invisible information recording sticker 1 of this embodiment, the infrared absorbing layer 4 which absorbs at least in the near infrared region of the recording wavelength is provided on the adhesive layer 2, and the contrast for reading is obtained. The thermosensitive recording layer 5, a concealing layer 6 which absorbs at least light in the visible region and transmits in the near infrared region of the recording wavelength and the reading wavelength, and a plurality of materials having different refractive indexes are laminated, and the color changes depending on the viewing angle. The multilayer vapor deposition layers 7 are sequentially laminated, and the base material 3 is provided between the first infrared absorption layer 4 and the adhesive layer 2.

Therefore, the multi-layered vapor-deposited layer 7 of which the color changes depending on the viewing angle is attached to the articles such as various products requiring anti-counterfeiting, and the anti-counterfeiting effect having the function as a certificate is obtained. The vapor-deposited laminate seal is a multilayer vapor-deposited layer 7
The invisible information can be recorded in a form integrated with the multilayer vapor-deposited layer 7 without impairing the aesthetics.

[Second Embodiment] FIG. 4 is a sectional view showing a structural example of an invisible information recording sticker 20 according to a second embodiment of the present invention. The same elements as those in FIG. 1 are designated by the same reference numerals. The description thereof will be omitted and only different parts will be described here. As shown in FIG. 4, in the invisible information recording sticker 1 of the present embodiment, the base material 3 in FIG.
It is configured to be provided between and. However, here, the base material 3 needs to be a material that can be regarded as transparent or almost transparent at least in the wavelength region of the reading wavelength 17. As described above, also in the invisible information recording sticker 20 of the present embodiment, the same operational effect as in the case of the first embodiment can be obtained, and the information recording method and the information reading method can also be the first embodiment. It is similar to the case of the example.

[Third Embodiment] FIG. 5 is a sectional view showing a structural example of an invisible information recording sticker 21 according to a third embodiment of the present invention. The same elements as those in FIG. 1 are designated by the same reference numerals. The description thereof will be omitted and only different parts will be described here. As shown in FIG. 5, the invisible information recording sticker 21 of this embodiment has a structure in which the base material 3 in FIG. 1 is provided between the concealing layer 6 and the multilayer vapor deposition layer 7. However, here, the base material 3 needs to be a material that can be regarded as transparent or almost transparent at the recording wavelength 16 and the reading wavelength 17. As described above, also in the invisible information recording sticker 21 of the present embodiment, the same operation and effect as in the case of the first embodiment can be obtained, and the information recording method and the information reading method can also be the first embodiment. It is similar to the case of the example.

[Fourth Embodiment (Hereinafter, this example is included in the present application.
However, it is referred to as the fourth embodiment . ) FIG. 6 is a cross-sectional view showing a configuration example of the invisible information recording sticker 22 according to the fourth embodiment of the present invention. Will be omitted and the description will be omitted, and only different parts will be described here. As shown in FIG. 6, the invisible information recording sticker 22 of this embodiment is configured such that the protective layer 8 in FIG. 1 is omitted and the base material 3 is provided on the multilayer vapor deposition layer 7. However, here, the base material 3 needs to be a material that can be regarded as transparent or almost transparent at the recording wavelength 16 and the reading wavelength 17. As described above, the invisible information recording sticker 2 of this embodiment
Also in 2, the same operation and effect as in the case of the first embodiment can be obtained, and the method of recording information and the method of reading information are the same as in the case of the first embodiment.

Next, a specific example of the invisible information recording sticker according to the first and fourth embodiments will be described.

(Specific Example 1) A transparent polyethylene terephthalate (PET) having a thickness of 25 μm is used as a base material 3, and an infrared absorbing material having the following composition is formed on the surface of the base material 3 by a gravure method so as to have a thickness of 2 μm. An infrared absorbing layer 4 was provided by coating and drying, and a leuco thermosensitive coloring material having the following composition was applied by a gravure method to a thickness of 5 μm and dried to provide a thermosensitive recording layer 5.

Next, a concealing layer forming material having the following composition was applied on the thermosensitive recording layer 5 by a gravure method to a thickness of 2 μm and dried to provide a concealing layer 6, and a multilayer vapor deposition layer having the following composition was formed. Forming material is 500n thick by vacuum evaporation method
m (5 layers) of multilayer vapor-deposited layer 7 is provided, and a protective layer-forming material having the following composition is applied to the multilayer vapor-deposited layer 7 by a gravure method to a thickness of 2 μm and dried to provide protective layer 9. It was

Next, the adhesive layer 2 is formed on the back surface of the base material 3.
(Acrylic resin, BPS3233D, manufactured by Toyo Ink Mfg. Co., Ltd.) was provided with a thickness of 15 μm by a gravure method and transferred to a release paper to obtain an invisible information recording sticker 1.

[Composition of Infrared Absorbing Material] Infrared absorbing dye NK2911 (manufactured by Japan Photosensitive Dye Research Institute) 2 parts (absorption peak is around 830 nm) Acrylic resin BR-56 Mitsubishi Rayon Co. 18 parts Solvent Toluene 78 parts [ Composition of Leuco Thermosensitive Coloring Material] Dye Fluoran compound PSD802 (manufactured by Nippon Soda Co., Ltd.) 4 parts Developer developer sulfone developer Papyrole CD180 (manufactured by Showa Denko KK) 8 parts Binder thermoplastic acrylic resin 8 parts Solvent toluene 80 parts [Composition of material for forming hiding layer] Gravure mixed color Sumi ink 68 parts Isocyanate curing agent Duranate 24A100 (manufactured by Asahi Chemical Industry Co., Ltd.) 2 parts Solvent Toluene 30 parts [Composition of material for forming multilayer vapor deposition layer] High refractive index layer TiO ₂ 100 nm Low refraction rate layer SiO ₂ 100 nm high refractive index layer / low refractive index layer / high refractive index / Low-refractive index layer / high-refractive index layer 5-layer structure [composition of protective layer forming material] thermoplastic acrylic resin BR-56 (manufactured by Mitsubishi Rayon Co., Ltd.) 16 parts polyethylene wax additive 100 (manufactured by Toyo Ink Mfg. Co., Ltd.) 10 Part Solvent Toluene 80 parts

(Specific Example 2) Transparent polyethylene terephthalate (PET) having a thickness of 25 μm is used as a base material 3, and a material for forming a multilayer vapor deposition layer having the composition of the specific example 1 is formed on the surface of the base material 3 by a vacuum vapor deposition method. A multilayer vapor-deposited layer 7 having a thickness of 500 nm (5 layers) was provided, and a concealing layer 6 having a thickness of 5 μm was provided by a gravure method using the concealing layer forming material having the composition of the specific example 1.

Next, a leuco-based thermosensitive coloring material having the composition of the specific example 1 was applied by a gravure method to a thickness of 5 μm and dried to provide a thermosensitive recording layer 5, and a red color having the composition of the specific example 1 was provided. An outer absorption material is applied by a gravure method to a thickness of 2 μm and dried to provide an infrared absorption layer 4, and an adhesive layer 2 (acrylic resin, BPS3233D, manufactured by Toyo Ink Mfg. Co., Ltd.) is further provided on the back surface of the base material 3. Providing a thickness of 15 μm by the gravure method,
It was transferred to a release paper to obtain an invisible information recording sticker 22.

A semiconductor laser having an oscillation wavelength of 830 nm and a beam diameter of 200 was added to the prototypes of specific examples 1 and 2 described above.
μm, irradiation intensity 200 mW, scan speed 10 cm
Irradiation was performed under the condition of / minute, and the barcode was recorded.

As a result, visually, the color changed depending on the viewing angle of the multilayer vapor deposition layer 20, effectively hiding the existence of the bar code. Further, the contrast at 940 nm between the recorded portion and the non-recorded portion was as shown in FIG. 17, and it was found that reading could be sufficiently performed.

[Fifth Embodiment] FIG. 7 is a sectional view showing a structural example of an invisible information recording sticker 23 according to a fifth embodiment of the present invention. The same elements as those in FIG. 1 are designated by the same reference numerals. The description thereof will be omitted and only different parts will be described here.

That is, the invisible information recording sticker 23 of this embodiment shown in FIG. 7 has a structure in which the hologram forming layer 9 is provided between the concealing layer 6 and the multilayer vapor deposition layer 7.

The hologram forming layer 9 is capable of forming minute unevenness which constitutes a relief type hologram composed of a picture, characters, etc. as a hologram image, has a good embossing property, is less likely to cause uneven press, and is a bright reproduced image. Is required to be obtained. For example,
Vinyl chloride-vinyl acetate copolymer resin, polycarbonate resin, polystyrene resin, thermoplastic resin such as polyvinyl chloride resin, unsaturated polyester resin, melamine resin,
Thermosetting resins such as epoxy resins, urethane resins, urethane (meth) acrylates, polyester (meth) acrylates, melamine (meth) acrylates, triazine (meth) acrylates, or mixtures thereof, and radical-polymerizable unsaturated groups. It is possible to use the thermoformable material which has. In addition to the above, it is possible to use a material having stability that can form a hologram image.

As described above, the invisible information recording sticker 2 of this embodiment
In the third aspect, in addition to the same effects as the first embodiment, the aesthetic effect of the hologram image is not impaired.
In addition, it becomes possible to record the invisible information in a form integrated with the hologram image, and the information recording method and the information reading method are the same as in the case of the first embodiment.

[Sixth Embodiment] FIG. 8 is a sectional view showing an example of the arrangement of an invisible information recording sticker 24 according to the sixth embodiment of the present invention. The same elements as those of FIG. 1 are designated by the same reference numerals. The description thereof will be omitted and only different parts will be described here.

As shown in FIG. 8, in the invisible information recording sticker 24 of this embodiment, the base material 3 in FIG.
And the concealing layer 6 are provided. However, here, the base material 3 needs to be a material that can be regarded as transparent or almost transparent at least in the wavelength region of the reading wavelength 17. As described above, also in the invisible information recording sticker 24 of the present embodiment, the same operational effect as in the case of the fifth embodiment can be obtained, and the information recording method and the information reading method can also be executed in the fifth embodiment. It is similar to the case of the example.

[Seventh Embodiment] FIG. 9 is a sectional view showing a structural example of an invisible information recording sticker 25 according to the seventh embodiment of the present invention. The same elements as those in FIG. 1 are designated by the same reference numerals. The description thereof will be omitted, and only different parts will be described here. As shown in FIG. 9, the invisible information recording sticker 25 of this embodiment has a structure in which the base material 3 in FIG. 7 is provided between the concealing layer 6 and the hologram forming layer 9. However, here, the base material 3 needs to be a material that can be regarded as transparent or almost transparent at the recording wavelength 16 and the reading wavelength 17. As described above, also in the invisible information recording sticker 25 of the present embodiment, the same operational effect as in the case of the fifth embodiment can be obtained, and the information recording method and the information reading method can also be executed in the fifth embodiment. It is similar to the case of the example.

[Eighth Embodiment (Hereinafter, this example is included in the present application.
However, it is referred to as the eighth embodiment . ) FIG. 10 is a cross-sectional view showing a configuration example of the invisible information recording sticker 26 according to the eighth embodiment of the present invention. Will be omitted and the description will be omitted, and only different parts will be described here. As shown in FIG. 10, in the invisible information recording sticker 26 of this embodiment, the protective layer 8 in FIG. 7 is omitted, and the hologram forming layer 6 and the multilayer vapor deposition layer 7 are reversed in stacking position.
The base material 3 is provided on the above. However, here, the base material 3 needs to be a material that can be regarded as transparent or almost transparent at the recording wavelength 16 and the reading wavelength 17.

In this case, it is a manufacturing problem that the order of laminating the hologram forming layer 6 and the multilayer vapor deposition layer 7 is different from that in the case of FIG. 1, and when laminating on the base material 3 of FIG. Is for embossing the hologram immediately before or after providing the multilayer vapor deposition layer 7.

[Ninth Embodiment] FIG. 11 shows a ninth embodiment of the present invention.
2 is a cross-sectional view showing a configuration example of the invisible information recording sticker 27 according to the embodiment of the present invention, in which the same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof is omitted, and only different portions will be described here. That is, as shown in FIG. 11, the invisible information recording sticker 1 of the present embodiment has a hologram forming concealment layer (concealment layer) in place of the concealment layer 6 between the thermal recording layer 5 and the multilayer vapor deposition layer 7 in FIG. A hologram forming concealing layer (10) which is also used as the layer 6 and the hologram forming layer is provided. However, here, the hologram forming concealing layer 10 is a layer having the characteristics of both the concealing layer 6 and the hologram forming layer 9, that is, at least light in the visible region is absorbed and the recording wavelength and the reading wavelength in the near infrared region. Through the
It is necessary to form a holographic image and can be formed by mixing the above materials with each other. As described above, also with the invisible information recording sticker 27 of the present embodiment, the same operation and effect as in the case of the fifth embodiment can be obtained, and in addition to this, the effect that the manufacturing process can be simplified is also obtained. To be The information recording method and the information reading method are the same as in the case of the fifth embodiment.

Although not shown, in the invisible information recording seals of FIGS. 8 to 10, other than the configuration of FIG.
In place of the hiding layer 6, a hologram forming hiding layer (hologram forming hiding layer which also serves as the hiding layer 6 and the hologram forming layer) 10 may be provided between the heat-sensitive recording layer 5 and the multilayer vapor deposition layer 7. Even in these invisible information recording stickers, the same operational effects as in the case of the fifth embodiment can be obtained, and in addition to this, the manufacturing process can be simplified. Also, how to record information,
Also, the information reading method is the same as in the case of the fifth embodiment.

Next, the fifth embodiment, the eighth embodiment,
A specific example of the invisible information recording sticker according to the ninth embodiment will be described.

(Specific Example 3) A transparent polyethylene terephthalate (PET) having a thickness of 25 μm was used as a base material 3, and an infrared absorbing material having the following composition was formed on the surface of the base material 3 by a gravure method to a thickness of 2 μm. An infrared absorbing layer 4 was provided by coating and drying, and a leuco thermosensitive coloring material having the following composition was applied by a gravure method to a thickness of 5 μm and dried to provide a thermosensitive recording layer 5.

Next, a concealing material having the following composition was coated on the thermosensitive recording layer 5 by a gravure method to a thickness of 2 μm and dried to form a concealing layer 6, and a hologram forming material having the following composition was gravure-coated. Method, a hologram image consisting of characters or pictures is embossed to form a hologram forming layer 7, and a transparent thin film layer 8 is formed of a multi-layer deposition layer forming material having the following composition in a vacuum. A multilayer vapor deposition layer 7 having a thickness of 500 nm (5 layers) is provided by vapor deposition, and a protective layer forming material having the following composition is applied to the multilayer vapor deposition layer 7 by gravure method to a thickness of 2 μm and dried. The protective layer 10 was provided.

Next, the adhesive layer 2 is formed on the back surface of the base material 3.
(Acrylic resin, BPS3233D, manufactured by Toyo Ink Mfg. Co., Ltd.) was provided by a gravure method to a thickness of 15 μm and transferred to a release paper to obtain an invisible information recording seal.

[Composition of Infrared Absorbing Material] Infrared absorbing dye NK2911 (manufactured by Japan Photosensitive Dye Research Institute) 2 parts (absorption peak is around 830 nm) Acrylic resin BR-56 Mitsubishi Rayon 18 parts Solvent Toluene 78 parts [ Composition of Leuco Thermosensitive Coloring Material] Dye Fluoran compound PSD802 (manufactured by Nippon Soda Co., Ltd.) 4 parts Developer developer sulfone developer Papyrole CD180 (manufactured by Showa Denko KK) 8 parts Binder thermoplastic acrylic resin 8 parts Solvent toluene 80 parts [Composition of hiding material] Gravure-based mixed color Sumi ink 68 parts Isocyanate curing agent Duranate 24A100 (manufactured by Asahi Kasei Corporation) 2 parts Solvent Toluene 30 parts [Hologram forming material composition] Urethane resin 20 parts Isocyanate curing agent Duranate 24A100 (Asahi Kasei 2) Solvent 78 parts ene [multilayered vapor deposition layer forming composition of the material] high refractive index layer TiO ₂ 100 nm low-refractive index layer SiO ₂ 100 nm high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer / high refractive index layer 5 composition of [protective layer forming material composition] thermoplastic acrylic resin BR-56 (manufactured by Mitsubishi Rayon Co., Ltd.) 16 parts polyethylene wax additive 100 (manufactured by Toyo Ink Mfg. Co., Ltd.) 10 parts solvent toluene 80 parts

(Specific Example 4) A transparent polyethylene terephthalate (PET) having a thickness of 25 μm is used as a base material 3, and a hologram forming material having the composition of the above specific example 3 is gravure-coated on the surface of the base material 3 to have a thickness of 1 μm. After coating and drying, a hologram image consisting of characters or patterns is embossed to form a hologram forming layer 9, and a multilayer vapor deposition layer forming material having the composition of the above-mentioned specific example 3 is applied by vacuum vapor deposition to a thickness of 500 nm. A (5 layers) multilayer vapor-deposited layer 7 was provided, and a hiding layer 6 having a thickness of 5 μm was provided by a gravure method using the hiding layer forming material having the composition of the above-mentioned specific example 3.

Next, a leuco thermosensitive coloring material having the composition of the above-mentioned specific example 3 was applied by a gravure method to a thickness of 5 μm and dried to provide a thermal recording layer 5, and a red color having the composition of the above-mentioned specific example 3 was provided. An outer absorption material is applied by a gravure method to a thickness of 2 μm and dried to provide an infrared absorption layer 4, and an adhesive layer 2 (acrylic resin, BPS3233D, manufactured by Toyo Ink Mfg. Co., Ltd.) is further provided on the back surface of the base material 3. Providing a thickness of 15 μm by the gravure method,
It was transferred to a release paper to obtain an invisible information recording sticker 26.

(Specific Example 5) Instead of the masking layer 6 and the hologram forming layer 7 of Example 3, a hologram forming masking material having the following composition was formed by a gravure method to a thickness of 6 μm.
After coating and drying the hologram forming masking layer 10 of m,
A holographic image consisting of characters or pictures was embossed. In addition, about the other processes, the invisible information recording sticker 27 was obtained in the same manner as in the case of the third specific example.

[0092] [Composition of hologram forming concealing material]     Urethane resin 20 parts     Isocyanate curing agent                     Duranate 24A100 (Made by Asahi Kasei Corporation) 2 parts     Infrared absorbing dye NK2911 (manufactured by Japan Photosensitive Dye Research Institute) 3 parts                     (Absorption peak is around 830 nm)     Gravure mixed color Sumi ink 25 parts     Solvent Toluene 50 parts

The prototypes of specific examples 3, 4, and 5 described above were irradiated with a semiconductor laser having an oscillation wavelength of 830 nm under the conditions of a beam diameter of 200 μm, an irradiation intensity of 200 mW, and a scan speed of 10 cm / min. Recorded the code.

As a result, although the color changed visually depending on the viewing angle of the multilayer vapor deposition layer 6, the transparent hologram image did not change at all, and the contrast at 940 nm between the recorded portion and the non-recorded portion was as shown in FIG. It turns out that the hidden barcode can be read sufficiently. As a result, the transparent hologram image did not change at all visually, but the contrast between the recorded portion and the non-recorded portion at 940 nm was as shown in the figure, and it was found that the barcode could be sufficiently read.

The present invention is not limited to the above embodiments, but can be implemented in the same manner as described below.

(A) In each of the embodiments shown in FIGS. 8, 9 and 10, as shown in the relationship between FIG. 7 and FIG. 11, one layer of the hologram forming concealing layer 10 which also serves as the concealing layer 6 and the hologram forming layer 9 is used. It goes without saying that it does not matter even if it becomes.

(B) The infrared absorption spectra of the infrared absorption layer 4 and the heat-sensitive recording layer 5 of each of the above-mentioned examples have a spectrum for absorbing a specific wavelength in the near infrared region, and these absorption wavelengths are They are different from each other.

(C) In each of the above embodiments, the protective layer 8 is not an essential element of the present invention and may be provided if necessary.

(D) The present invention can be used as an information recording medium such as a transfer foil or a card by changing the constitution of the base material in addition to the seal shape.

[0100]

As described above, according to the invention of claim 1 , on the adhesive layer, at least an infrared absorption layer which exhibits absorption in the near infrared region of the recording wavelength, a thermosensitive recording layer, and at least a visible region. A concealing layer that absorbs light and transmits in the near-infrared region of the recording wavelength and the reading wavelength, a multilayer vapor deposition layer in which a plurality of materials having different refractive indices are laminated and the color of which changes depending on the viewing angle are sequentially laminated, and the red Between the outer absorption layer and the adhesive layer,
Between the masking layer and the heat sensitive recording layer or to any of the layers between the masking layer and the multilayer deposition layer, so was provided a substrate comprising a multilayer deposition laminate changes color by visual angle, It is attached to articles such as various products that require anti-counterfeiting, has a forgery-preventing effect having a function as a certificate, and does not impair the aesthetics of the multilayer vapor-deposited laminate, and is a multilayer vapor-deposited laminate. An invisible information recording sticker capable of recording invisible information can be provided in an integrated form.

Further, according to the invention of claim 2 or 3 , on the adhesive layer, an infrared absorption layer which absorbs at least in the near infrared region of the recording wavelength, a heat sensitive recording layer, and at least light in the visible region is absorbed. , A hologram forming layer (or a hologram forming masking layer) for forming a hologram image and a masking layer transmitting a near infrared region of a recording wavelength and a reading wavelength, and the hologram forming layer (or the hologram forming masking layer) has a refractive index A plurality of different materials are laminated, and a multilayer vapor deposition layer whose color changes depending on the viewing angle is sequentially laminated, and a thermal recording layer and a hiding layer (or a hologram forming hiding layer) are provided between the infrared absorption layer and the adhesive layer. to any of the layers between or during the hiding layer and the hologram forming layer, and, since the provided substrate, the multilayer deposition laminates and magnetic which changes color by visual angle It has a holographic image and is attached to articles such as various merchandise that require anti-counterfeiting, and has the effect of anti-counterfeiting that has the function of a certificate. Without compromising
In addition, an invisible information recording sticker capable of recording invisible information can be provided in a form integrated with the multilayer vapor-deposited laminate and the transparent hologram image.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of an invisible information recording sticker according to the present invention.

FIG. 2 is a cross-sectional view for explaining an example of the information recording method of the invisible information recording sticker in the first embodiment.

FIG. 3 is a conceptual diagram showing an example of an infrared reflection spectrum of the invisible information recording sticker of the present invention.

FIG. 4 is a sectional view showing a second embodiment of the invisible information recording sticker according to the present invention.

FIG. 5 is a sectional view showing a third embodiment of the invisible information recording sticker according to the present invention.

FIG. 6 is a sectional view showing a fourth embodiment of the invisible information recording sticker according to the present invention.

FIG. 7 is a sectional view showing a fifth embodiment of the invisible information recording sticker according to the present invention.

FIG. 8 is a sectional view showing a sixth embodiment of the invisible information recording sticker according to the present invention.

FIG. 9 is a sectional view showing a seventh embodiment of the invisible information recording sticker according to the present invention.

FIG. 10 is a sectional view showing an eighth embodiment of the invisible information recording sticker according to the present invention.

FIG. 11 is a sectional view showing a ninth embodiment of the invisible information recording sticker according to the present invention.

[Explanation of symbols]

1, 20, 21, 22, 23 ... Invisible information recording seal 24, 25, 26, 27 2 ... Adhesive layer 3 ... Substrate 4 ... Infrared absorbing layer 5 ... Thermal recording layer 6 ... Concealment Layer 7 ... Multi-layer vapor deposition layer 8 ... Protective layer 9 ... Hologram forming layer 10 ... Hologram forming concealing layer 11 ... Ray of absorption wavelength of infrared absorption layer 12 ... Heat generation 13 ... Recording portion 14 ... Red Reflection spectrum 15 (a) of the outer absorption layer ... Reflection spectrum 15 (b) of the colored portion of the thermosensitive recording layer 5 ... Reflection spectrum 16 of the uncolored portion of the thermosensitive recording layer 5 ... Recording wavelength 17 ... Read wavelength

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-286366 (JP, A) JP-A-6-247084 (JP, A) JP-A-6-286364 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G09F 3/00-3/03 B42D 15/10 501 G02B 5/18 G03H 1/18 G09F 19/12

Claims (7)

(57) [Claims] 1. An infrared absorbing layer which absorbs at least in the near infrared region of a recording wavelength on a pressure-sensitive adhesive layer, a thermosensitive recording layer, absorbs at least light in the visible region, and transmits the near infrared region of a recording wavelength and a reading wavelength. A concealing layer, a multilayer vapor deposition layer in which a plurality of materials having different refractive indices are laminated, and the color of which changes depending on the visual angle, are sequentially laminated, and the thermal recording layer is provided between the infrared absorbing layer and the adhesive layer. A non-visible information recording sticker comprising a base material provided between any one of the above and the hiding layer or between the hiding layer and the multilayer vapor deposition layer. 2. An infrared absorbing layer which absorbs at least in the near infrared region of a recording wavelength on a pressure-sensitive adhesive layer, a thermosensitive recording layer, which absorbs at least light in the visible region and transmits the near infrared region of a recording wavelength and a reading wavelength. A hiding layer for forming a hologram image, a hologram forming layer for forming a hologram image, a multilayer vapor deposition layer in which a plurality of materials having different refractive indexes are laminated and whose color changes depending on the viewing angle, and the infrared absorbing layer and Invisible, characterized in that a substrate is provided between the adhesive layer, the heat-sensitive recording layer and the hiding layer, or between the hiding layer and the hologram forming layer. Information record sticker. 3. At least light in the visible region is absorbed and transmitted in the near infrared region of the recording wavelength and the reading wavelength, and
The invisible information recording sticker according to claim 2, further comprising a hologram formation concealing layer formed by forming a hologram image. Wherein said heat-sensitive recording layer on the adhesive layer, according to claim 1, characterized in that formed by laminating in this order of the infrared-absorbing layer or
Or the invisible information recording sticker described in 2 . Wherein said infrared-absorbing layer, claims 1 to 3, characterized in that it has an absorption in a specific wavelength in the near infrared region
The invisible information recording sticker according to any one of 1. Wherein said heat-sensitive recording layer, claims 1 to 3 color portion is characterized by having an absorption in different wavelength ranges from the specific wavelength in the near infrared region absorbing the infrared absorbing layer
The invisible information recording sticker according to any one of 1. Wherein said multilayer deposited layer, invisible information according to any one of claims 1 to 4, wherein the refractive index is formed by laminating a plurality of different ceramic materials with each other Record sticker.