JP2002019344A - Information recording medium, printed matter, and playback device - Google Patents

Abstract

(57) [Summary] Information recording medium excellent in anti-counterfeiting property, printed matter capable of imparting excellent anti-counterfeiting property to information recording medium, and usable for authenticity determination of such information recording medium To provide a playback device. An information recording medium according to the present invention includes an information recording base material, and print patterns provided on the information recording base material. , 22 are characterized by containing a first color material that changes color by applying an electromagnetic field and a second color material that does not change color by applying the electromagnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium, a printed matter, and a reproducing apparatus, and more particularly to an information recording medium provided with forgery / falsification prevention measures, and a method for imparting forgery / falsification prevention to an information recording medium. The present invention relates to a printed material that can be used in a computer, and a reproducing apparatus that can be used for authenticity determination of an information recording medium that has been subjected to counterfeit / forgery prevention measures.

[0002]

2. Description of the Related Art In recent years, input / output devices such as scanners, printers, and copiers, personal computers, and image processing software have become more sophisticated, and high-precision forgery is possible even with commercially available devices. In order to deal with such situations, IDs used for securities and personal authentication
The card employs various anti-counterfeiting techniques.

As one of such forgery prevention techniques, a technique of recording security information as a latent image (invisible information) is used. As a forgery prevention technology using a latent image, a magnetic forgery prevention technology is typical. For example, in securities, etc., a printing section using magnetic ink containing magnetic powder is provided at a predetermined position, and authenticity is determined by detecting the presence or absence of magnetism or a magnetic pattern. According to an ID card or the like, personal information or the like is performed by magnetically recording information on a magnetic stripe and reproducing the information.

[0004] However, in the magnetic forgery prevention technology,
In order to reproduce information recorded as a latent image, a dedicated and expensive reproducing apparatus is required. In addition, a person who has some expertise can easily read recorded information. Therefore, the magnetic forgery prevention technology has a weaker forgery resistance and requires a technology with higher security.

As forgery prevention technology, in addition to such forgery prevention technology using a latent image, a technology using a hologram or a diffraction pattern is also known. For example, hologram patterns are formed on many ID cards, and hologram slits are formed on banknotes, gift certificates, and the like in certain countries.

According to the hologram technology, a fine diffraction image with high visibility can be obtained due to recent technological advances. However, there is a disadvantage that the production requires a high technology and the production cost is high. further,
Holograms are generally considered to be difficult to counterfeit and effective as anti-counterfeiting means, but such light diffraction structures are obtained by duplication techniques,
The same type of ID card uses the same light diffraction structure. Therefore, for example, it is easy to adopt a method of cutting out a hologram part from a real credit card and sticking it to a counterfeit credit card.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an information recording medium having excellent anti-counterfeiting properties, and a printed material capable of imparting an information recording medium with excellent anti-counterfeiting properties. It is another object of the present invention to provide a reproducing apparatus which can be used for authenticity determination of such an information recording medium.

[0008]

In order to solve the above-mentioned problems, the present invention comprises an information recording substrate and a printing pattern provided on the information recording substrate, wherein the printing pattern is an electromagnetic field. The present invention provides an information recording medium characterized by containing a first color material that causes a color change by acting on the first color material and a second color material that does not cause a color change by acting on the electromagnetic field.

Further, the present invention comprises an information recording base material and a print pattern provided on the information recording base material,
The printed pattern contains a first color material that changes a dielectric constant by applying an electromagnetic field and a second color material that does not change a dielectric constant by applying the electromagnetic field. A recording medium is provided.

[0010] The present invention also includes an information recording substrate, an electrode pattern provided on the information recording substrate, and a print pattern provided on the information recording substrate.
The printing pattern contains a coloring material that causes a change in dielectric constant by applying an electromagnetic field, and that at least a part of the electrode pattern is interposed between a part of the printing pattern and the information recording base material. An information recording medium is provided.

Further, the present invention comprises a printing base material and a printing pattern formed on the printing base material, wherein the printing pattern causes a color change by applying an electromagnetic field. And a second color material that does not change color by applying the electromagnetic field.

Further, the present invention comprises a printing substrate and a printing pattern formed on the printing substrate, wherein the printing pattern has a first color which causes a change in dielectric constant by applying an electromagnetic field. A printed material characterized by containing a material and a second color material that does not cause a change in dielectric constant by applying the electromagnetic field.

Further, the present invention comprises an information recording substrate and a printing pattern provided on the information recording substrate, wherein the printing pattern has a first color which changes color by applying an electromagnetic field. An apparatus for reproducing an information recording medium containing a material and a second color material that does not change color by applying the electromagnetic field, comprising: an electromagnetic field forming mechanism that applies an electromagnetic field to the print pattern; and There is provided a reproducing apparatus having a window for observation.

Further, the present invention comprises an information recording base material and a printing pattern provided on the information recording base material,
The printing pattern is an information recording medium reproducing apparatus containing a first color material that causes a change in dielectric constant by applying an electromagnetic field and a second color material that does not cause a change in dielectric constant by applying the electromagnetic field. A reproducing apparatus comprising: an electromagnetic field generating mechanism for applying an electromagnetic field to the print pattern; and a reading mechanism for applying an electromagnetic field to the print pattern and reading a dielectric constant distribution of the print pattern as an electric signal. I will provide a.

The term "information recording medium" used herein means a medium on which character information or image information is recorded and countermeasures for which counterfeit prevention is required, such as ID cards, credit cards, certificates, and securities. I do. Also, the term "printed material" means a printed material that can be used to impart anti-counterfeiting properties to the medium, such as an adhesive seal, an adhesive sticker, and an adhesive sheet. Also, the term "color"
Is used in connection with hue, saturation, and lightness, and the term "creating a color change" means causing a change in at least one of hue, saturation, and lightness.

As described above, in the present invention, a printed pattern containing the first color material and the second color material is formed. The first colorant that forms the printing pattern changes its color and dielectric constant by applying an electric or magnetic field, while the second colorant changes its color or dielectric constant even when an electric or magnetic field is applied. Does not occur. Therefore, according to the present invention, the authenticity can be determined by an extremely simple method of applying an electric or magnetic field.

Further, in the present invention, since a printing method is used for imparting anti-counterfeiting properties, it is easy to record different information for each medium and to form a complicated pattern. Further, when the printing method is used, it is impossible to rewrite recorded information, unlike the case where a magnetic stripe or the like is provided. That is, according to the present invention, forgery prevention is extremely difficult while providing forgery prevention properties is easy.

In the present invention, as the first coloring material, a liquid crystal microcapsule comprising a liquid crystal material sensitive to an electromagnetic field in a thin film such as a polymer film can be used. In this case, the liquid crystal material preferably contains a dichroic dye. In the case where the first colorant causes a color change by applying an electromagnetic field, the first colorant includes a mixture of a liquid and a colorant that causes electrophoresis in a thin film. Capsules can be used.

In the present invention, commonly used pigments and dyes can be used as the second color material. The second coloring material may be colored like a coloring pigment or non-colored like an extender. In addition, as the second color material, a microcapsule including a pigment, a dye, or the like in a thin film can be used.

In the present invention, the first color material and the second color material constituting the print pattern may be mixed uniformly or non-uniformly. Further, the first color material and the second color material may be respectively formed as the first pattern and the second pattern without being mixed. In this case, the first pattern and the second pattern may constitute a single symbol or character, or the first pattern and the second pattern may constitute different symbols or characters. You may. Further, the first pattern and the second pattern may be formed to be adjacent to each other, may be formed to partially or completely overlap, or may be separated from each other. When information recorded as a latent image is reproduced using a color change of the first color material by applying an electromagnetic field, at least a part of the first pattern is not covered with the second pattern. Is preferred.

In the present invention, a protective layer or the like can be provided on the print pattern. The protective layer is preferably transparent, but may not be transparent when the substrate is transparent or when color change is not used for reproducing information recorded as a latent image.

In the present invention, the surface of the substrate may be conductive. For example, a conductive thin film can be provided on a base material, and a printed pattern can be formed thereon. in this case,
In applying an electric or magnetic field to a printed pattern,
A conductive thin film can be used as an electrode.

When a conductive thin film is provided on a substrate, another conductive thin film may be provided on the printed pattern. That is, a structure in which the printed pattern is sandwiched between a pair of conductive thin films that are insulated from each other may be employed. For example, a conductive thin film and a printing pattern are sequentially provided on a base material, and separately, a base material having a conductive thin film formed on one main surface is prepared, and a printing pattern is formed between the pair of conductive thin films. It can be stuck so as to be sandwiched. In this case, at least one of the substrates is preferably transparent, and the conductive thin film on the transparent substrate is also preferably transparent. It is preferable to provide terminals for connecting the conductive thin film to an external power supply.

In the present invention, when utilizing the color change of the first color material by applying an electromagnetic field to the reproduction of information recorded as a latent image on an information recording medium, for example, an electromagnetic field for applying an electromagnetic field to a print pattern A reproducing apparatus having a forming mechanism and a window for observing a print pattern can be used. The electromagnetic field forming mechanism can be composed of, for example, a pair of flat electrodes for applying a voltage to a print pattern on an information recording medium and a power supply. At least one of the flat electrodes is, for example, a transparent electrode formed on one main surface of a transparent substrate constituting a window. In this case, the color change of the first coloring material can be observed by applying a voltage while sandwiching the medium between the pair of flat electrodes.

Further, as described above, when a structure in which a printed pattern is sandwiched between a pair of conductive thin films or the like is employed and terminals are provided for connection between the conductive thin films and an external power supply, the reproducing apparatus may be provided with such a structure. What is necessary is just to be able to apply a predetermined voltage between terminals.

In the present invention, when utilizing the change in the dielectric constant of the first coloring material by applying an electromagnetic field to the reproduction of information recorded as a latent image on an information recording medium, for example, the electromagnetic field is applied to a print pattern. A reproducing apparatus having an electromagnetic field generating mechanism and a reading mechanism for reading a dielectric constant distribution of the print pattern as an electric signal by applying an electromagnetic field to the print pattern can be used.

The electromagnetic field generating mechanism may be, for example, a mechanism for applying an electromagnetic field simultaneously to the entire print pattern, or a mechanism for sequentially applying the electromagnetic field from one end to the other end of the print pattern. Similarly, the reading mechanism may apply an electromagnetic field to the entire print pattern simultaneously, or may apply an electromagnetic field sequentially from one end to the other end of the print pattern. When the state of the first color material changes from the normal state by repeating the reproduction of information, a stronger electromagnetic field may be applied to the print pattern. Further, when the electromagnetic field generating mechanism applies a voltage to the print pattern, a voltage used for reading information can be superimposed thereon.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. In each of the drawings, similar members are denoted by the same reference numerals, and redundant description will be omitted. First, the principle common to the first to third embodiments of the present invention will be described with reference to FIG.

FIG. 1 is a schematic diagram for explaining a forgery prevention technique according to the first to third embodiments of the present invention.
(A) is a cross-sectional view of the information recording medium in a voltage non-applied state, and (b) is a cross-sectional view of the information recording medium in a voltage applied state. As shown in FIG. 1, an information recording medium 10 according to the first to third embodiments of the present invention mainly includes an information recording base material 11 and a print pattern 12 formed on one main surface thereof. Is configured. The printing pattern 12 includes, as one kind of the coloring material, a liquid crystal microcapsule 13 including a mixture of an electric field-sensitive liquid crystal material and a dichroic dye in a transparent thin film. The print pattern 12
Contains, as another color material, a color material that does not change color even when an electric field is applied.

For example, as shown in FIGS. 1A and 1B, a structure in which a printed pattern 12 is sandwiched between a pair of electrodes 14 and 15 is adopted, and these electrodes 14 and 15 can be connected to a power supply 16. I do. In this case, when no voltage is applied,
As shown in FIG. 1A, the orientation direction of the liquid crystal molecules in the liquid crystal microcapsules 13 is substantially parallel to the substrate surface, and therefore, the orientation direction of dichroic dye molecules (not shown) is also substantially parallel to the substrate surface. It is.

A dichroic dye absorbs light parallel to the absorption axis (usually substantially perpendicular to the molecular axis) and hardly absorbs light perpendicular to the absorption axis. Therefore, when the medium 10 is observed as indicated by the arrow 18, the amount of light absorption by the dichroic dye becomes maximum when no voltage is applied.

On the other hand, when a voltage is applied, the orientation direction of the liquid crystal molecules in the liquid crystal microcapsules 13 is perpendicular to the substrate surface as shown in FIG. 1B, and therefore, the dichroic dye molecules (not shown) The orientation direction is also perpendicular to the substrate surface. Therefore, when the medium 10 is observed as indicated by an arrow 18, the amount of light absorbed by the dichroic dye is minimal when a voltage is applied.

That is, the color of the print pattern 12 is different between when no voltage is applied and when a voltage is applied. Therefore, by utilizing this, a latent image which cannot be identified in a normal state and which can be viewed by applying a voltage is formed. can do.

In the information recording medium 10, the base material 11
For example, various cards such as an ID card and an IC card, and various securities such as bills and receivables can be used. As a material of the base material 11, vinyl chloride, PET, paper, or the like can be used. In addition, as the material of the base material 11, metals and alloys such as iron, SUS, aluminum, and copper, and composite materials in which a metal or an alloy is coated with a resin such as polyurethane can be used. The substrate 11 may be flexible, such as paper or a plastic sheet, or rigid, such as a metal plate or a plastic card.

In the liquid crystal microcapsules 13 constituting the print pattern 12, as the liquid crystal material, for example, liquid crystal compounds represented by the following general formulas (1) to (10) can be used.

[0036]

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In the above general formulas (1) to (10), the substituents R and X each represent an alkyl group, an alkoxy group, an alkylphenyl group, an alkoxyalkylphenyl group, an alkoxyphenyl group, an alkylcyclohexyl group, an alkoxyalkyl group. Cyclohexyl group, alkylcyclohexylphenyl group, cyanophenyl group, cyano group, halogen atom, fluoromethyl group, fluoromethoxy group, alkylphenylalkyl group, alkoxyalkylphenylalkyl group, alkoxyalkylcyclohexylalkyl group, alkylcyclohexylalkyl group,
It represents an alkoxyalkoxycyclohexylalkyl group, an alkoxyphenylalkyl group, or an alkylcyclohexylphenylalkyl group, and the substituent Y represents a hydrogen atom or a halogen atom.

The above substituents R and X may have an alkyl chain or an alkoxy chain having optical activity, or may have a phenyl group or a phenoxy group substituted with a halogen atom such as a fluorine atom or a chlorine atom. . Further, the substituents R and X may have a phenyl group in which a hydrogen atom is substituted with one or two halogen atoms such as a fluorine atom and a chlorine atom.

As the liquid crystal material, the above general formulas (1) to (1)
A liquid crystal composition in which the liquid crystal compound shown in (10) is mixed can also be used. In addition, all of the liquid crystal compounds represented by the general formulas (1) to (10) have a positive dielectric anisotropy.
A liquid crystal compound having a negative dielectric anisotropy can also be used. For example, as the liquid crystal material, a liquid crystal composition in which a liquid crystal compound having a negative dielectric anisotropy and a liquid crystal compound having a positive dielectric anisotropy are mixed so that the dielectric anisotropy becomes positive can be used. When an appropriate element configuration and driving method are used, a liquid crystal compound or a liquid crystal composition having a negative dielectric anisotropy can be used as a liquid crystal material. Further, as a liquid crystal material, a liquid crystal compound or a liquid crystal composition in which a chiral material is added can be used.

The dichroic dyes to be added to the liquid crystal material include yellow dyes represented by the following chemical formulas (11) to (19), magenta dyes represented by the following chemical formulas (20) to (27), and the following chemical formula (28) To (31).

[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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The mixing ratio of the dichroic dye to the liquid crystal compound or liquid crystal composition is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight.
If the mixing ratio of the dichroic dye is less than the lower limit, sufficient contrast cannot be obtained. If the mixing ratio is more than the upper limit, the coloring may remain even when voltage is applied, and the contrast may be reduced.

Examples of the transparent film containing the liquid crystal material include: polyethylene; chlorinated polyethylene; ethylene / vinyl acetate copolymer, ethylene / acrylic acid / maleic anhydride copolymer and other ethylene copolymers; ;
Polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate;
Polypropylene; Polyisobutylene; Polyvinyl chloride; Natural rubber; Polyvinylidene chloride; Polyvinyl acetate; Polyvinyl alcohol; Polyvinyl acetal; Polyvinyl butyral; Resins; fluorinated ethylene / propylene resins; vinylidene fluoride resins; vinyl fluoride resins; tetrafluoroethylene / perfluoroalkoxyethylene copolymers, tetrafluoroethylene / perfluoroalkylvinyl ether copolymers, Tetrafluoroethylene copolymers such as fluorinated ethylene hexafluoropropylene copolymers and tetrafluoroethylene ethylene copolymers; fluororesins such as fluorinated polybenzoxazole; acrylic resins; methacrylic resins; Fumaric acid resins; Maleic acid resins; Polyacryl Nitriles; Acrylonitrile copolymers such as acrylonitrile / butadiene / styrene copolymers; Polystyrenes; Styrene / acrylonitrile copolymers / etc .; Acetal resins; Polyamides such as nylon 66; Polycarbonates; Phenolic resins; urea resins; epoxy resins; unsaturated polyester resins; alkyd resins; melamine resins; polyurethanes; diaryl phthalate resins; polyphenylene oxides; polyphenylene sulfides; polysulfones; Phenyl sulfones; silicone resins;
Almost all polymer materials such as polyimides; bismaleimide triazine resins; polyimide amides; polyether imides; polyvinyl carbazoles; norbornene-based amorphous polyolefins; and celluloses can be used.

The liquid crystal microcapsules 13 configured as described above can be prepared by a film emulsification method, a phase separation method, a liquid drying method, an interfacial polymerization method, an in situ polymerization method, a liquid curing coating method, or a spray drying method. Can be manufactured using a conventionally used method.

The ink for forming the print pattern 12 on the base material 11 may further contain a binder resin in addition to the liquid crystal microcapsules 13. Examples of such binder resins include polyethylenes; chlorinated polyethylenes; ethylene copolymers such as ethylene-vinyl acetate copolymers, ethylene-acrylic acid-maleic anhydride copolymers; polybutadienes; polyethylene terephthalate, polybutylene. Polyesters such as terephthalate and polyethylene naphthalate; polypropylenes; polyisobutylenes; polyvinyl chlorides; polyvinylidene chlorides; polyvinyl acetates;
Polyvinyl acetal; polyvinyl butyral; ethylene tetrafluoride resin; ethylene trifluorochloride resin;
Fluorinated ethylene / propylene resins; vinylidene fluoride resins; vinyl fluoride resins; ethylene tetrafluoride / perfluoroalkoxyethylene copolymer, ethylene tetrafluoride / perfluoroalkylvinyl ether copolymer, ethylene tetrafluoride・ Polytetrafluoroethylene copolymer such as propylene hexafluoride copolymer, ethylene tetrafluoride / ethylene copolymer; fluororesins such as fluorine-containing polybenzoxazole; acrylic resins; methacryl such as polymethyl methacrylate Resins; polyacrylonitriles; acrylonitrile copolymers such as acrylonitrile-butadiene-styrene copolymer; polystyrenes; halogenated polystyrenes; styrene-methacrylic acid copolymer, styrene
Styrene copolymers such as acrylonitrile copolymers; ionic polymers such as sodium polystyrene sulfonate and sodium polyacrylate; acetal resins; polyamides such as nylon 66; gelatin; gum arabic; polycarbonates; polyester carbonates; Resins; phenolic resins; urea resins;
Epoxy resins; unsaturated polyester resins; alkyd resins; melamine resins; polyurethanes; diaryl phthalate resins; polyphenylene oxides; polyphenylene sulfides; polysulfones; polyphenylsulfones;
Use of thermoplastic resins such as bismaleimide triazine resins; polyimide amides; polyether sulfones; polymethylpentenes; polyether ether ketones; polyetherimides; polyvinyl carbazoles; and norbornene-based amorphous polyolefins. Can be.

When these binders are water-soluble, for example, ink can be prepared by using water as a dispersion medium and dispersing the binder and the liquid crystal microcapsules 13 therein. On the other hand, when the binder is water-insoluble, for example, an ink can be prepared by using water as a dispersion medium and dispersing the binder and the liquid crystal microcapsules 13 into an emulsion. The binder content in the ink is the liquid crystal microcapsule 1
It is preferably 50% or less of 3. The smaller the binder content, the more the volume ratio of the liquid crystal material in the print pattern 12 increases, so that the color change appears more remarkably.

The printing pattern 12 can be formed by a known printing method using the above-described ink. The ink used to form the print pattern 12 is an ink containing a colorant that does not change color even when an electric field is applied,
That is, it can contain a usual ink that has been used conventionally.

Next, the first to third embodiments will be sequentially described. FIG. 2A is a plan view schematically showing an information recording medium according to the first embodiment of the present invention.
(B) is a side view thereof. Information recording medium 1 shown in FIG.
Numeral 0 is a personal authentication card such as an employee card. The personal authentication card 10 has an information recording base material 11 made of plastic or the like, and on one main surface thereof, an image 21 such as a face photograph of the person, an employee number,
Characters 22 such as name, issue date, and expiration date are printed. The print pattern composed of the image 21 and the characters 22 is formed using an ink containing a color material that does not cause a color change even when an electric field is applied, that is, an ordinary ink conventionally used. .

On the surface of the substrate 11 on which the image 21 and the characters 22 are printed, a printing pattern such as a logo mark constituting a security image is further formed. The printing pattern 12 is formed using an ink containing a coloring material that changes color by the action of an electric field. At least one kind of the coloring material includes an electric field-sensitive liquid crystal material and a dichroic material. A liquid crystal microcapsule 13 containing a mixture with a dye in a transparent thin film is included. Base material 11
A transparent resin film or the like is adhered to a surface on which the image 21, the character 22, and the print pattern 12 are formed as a protective film 23 for protecting them.

The print pattern 12 can be formed, for example, by using an ink containing the liquid crystal microcapsules 13 manufactured by the following method. First, ZLI manufactured by Merck, which is a nematic liquid crystal having a positive dielectric anisotropy.
80 parts by weight of -1840, 1 part by weight of G-176 manufactured by Japan Photographic Dye Laboratories, which is a magenta dichroic dye, 7 parts by weight of a hydrophilic methyl methacrylate monomer, and hydrophobic isobutyl methacrylate. 7 parts by weight, 1 part by weight of a crosslinking agent ethylene glycol dimethacrylate, and 0.2 part by weight of benzoyl peroxide are mixed and dissolved. Using a homogenizer, 3 parts by weight of polyvinyl alcohol and 3 parts by weight
An emulsion is obtained by dispersing in a mixture with 00 parts by weight of pure water.

The emulsion was heated at a temperature of 85 ° C., 500
The above monomer component is polymerized by stirring at a stirring speed of rpm for 1 hour. After 1 hour, the mixture was filtered through a filter having a pore size of 1 μm, and washed three times with pure water to obtain an average particle size of 6 μm.
A μm liquid crystal microcapsule 13 is obtained.

The ink is prepared by dispersing the thus prepared liquid crystal microcapsules 13 in a 5% dispersion of vinyl acetate fine particles having an average particle size of 0.5 μm so that the concentration becomes 10%. . The print pattern 12 is
It can be formed using the ink obtained as described above.

The authenticity determination of the personal authentication card 10 shown in FIG. 2 can be performed using, for example, the apparatus shown in FIG. FIG. 3A is a perspective view schematically showing a reproducing apparatus used for authenticity determination of the personal authentication card 10 according to the first embodiment of the present invention, and FIG. It is sectional drawing in a surface. The playback device 30 shown in FIG. 3 has a housing 32 having an insertion slot 31 for inserting the personal authentication card 10.
And a transparent substrate 33 provided in the housing 32 and constituting a window.
And a transparent electrode 15 provided on a surface of the transparent substrate 33 facing the personal authentication card 10, a support plate 35 mounted in the housing 32, and an electrode 14 provided on the support plate 35.
It is mainly composed of The electrodes 14 and 15 can be connected to a power supply 16.

The authenticity determination of the personal authentication card 10 using the reproducing device 30 is performed by the following method, for example. First, the personal authentication card 10 is inserted into the insertion port 31 of the playback device 30.
And loaded inside by a mechanism not shown. The personal authentication card 10 is inserted with the printed pattern 12 facing the transparent substrate 33 so that the printed pattern 12 can be observed from the transparent substrate 33 made of transparent glass or resin. Next, an AC voltage is applied between the electrodes 14 and 15 from the power supply 16. As a result, the orientation direction of the dichroic dye molecules in the liquid crystal microcapsules 13 forming the print pattern 12 changes, and the security image 12, which was clearly visible when no voltage is applied, has a reduced contrast. It becomes difficult. By observing the presence or absence of such a change, the authenticity of the personal authentication card 10 can be easily determined.

The background of the print pattern 12 that undergoes a color change upon application of a voltage is formed on the substrate 11 by using a colorant which does not undergo a color change upon application of a voltage or a microcapsule of such a colorant. You can also. For example, when an inverted pattern having the same color as the color of the print pattern 12 when no voltage is applied is formed as such a background, the print pattern 12 and the background have the same color when no voltage is applied. It will be difficult to understand. That is, the print pattern 12 can be used as a latent image.

Next, a second embodiment of the present invention will be described. FIG. 4A is a plan view schematically showing an information recording medium according to a second embodiment of the present invention, and FIG.
FIG. 4C is a side view along the line BB, and FIG.
It is sectional drawing which followed the -C line. The information recording medium 10 shown in FIG. 4 is a personal authentication card such as an employee card, and includes a base material 11, an intermediate member 25 embedded in a concave portion formed on one surface of the base material 11, and a base material. It mainly comprises a protective film 23 provided on the surface of the material 11 in which the intermediate member 25 is embedded. Reference numeral 24 indicates a true / false determination unit. Each member constituting the personal authentication card 10 shown in FIG. 4 will be described with reference to FIGS.

FIG. 5A is a plan view of the base material 11 used for the personal authentication card 10 shown in FIG. 4, and FIG.
Is a cross-sectional view along the line DD. FIG.
FIG. 6A is a plan view of an intermediate member 25 used in the personal authentication card 10 shown in FIG. 4, and FIG. 6B is a plan view of a protective film 23 used in the personal authentication card 10 shown in FIG. is there.

The base material 11 shown in FIGS. 5 (a) and 5 (b) is made of plastic or the like, and on one main surface thereof, an image 21 such as a photograph of the person, an employee number, a name, and a date of issue are provided. , And an expiration date 22 are printed. The print pattern composed of the image 21 and the characters 22 is formed using an ink containing a color material that does not cause a color change even when an electric field is applied, that is, an ordinary ink conventionally used. . Further, a concave portion 26 is provided on the surface of the base material 11 on which the image 21 and the character 22 are printed, and the electrode 14 is formed on the bottom surface of the concave portion 26.

The intermediate member 25 shown in FIG.
It has a flat plate shape that fits into one recess 26. An opening 27 is provided in the intermediate member 25. On one main surface of the intermediate member 25, a print pattern 12 such as a logo mark constituting a security image is formed. The security image 12 is formed by using an ink containing a coloring material that undergoes a color change by applying an electric field, and at least one of the coloring materials includes an electric field-sensitive liquid crystal material and a dichroic material. A liquid crystal microcapsule 13 containing a mixture with a dye in a transparent thin film is included. Further, a transparent electrode 15 is formed on the other main surface of the intermediate member 25.

The protective film 23 shown in FIG. 6B is a transparent resin film or the like. An opening 28 is provided in the protective film 23. The opening 28 partially exposes the electrodes 14 and 15 in the personal authentication card 10 shown in FIG.

As is clear from the above description, the authenticity determination section 24 of the personal authentication card 10 shown in FIG. 4 has the security image 12 sandwiched between the electrodes 14 and 15 and the electrodes 14 and 15 It has a structure partially exposed inside. Therefore, the personal authentication card 1 shown in FIG.
The determination of the authenticity of 0 is performed by connecting a pair of terminals connected to the AC power supply to
This can be performed by a very simple method of connecting to the electrodes 14 and 15 exposed in the opening 28, respectively. That is, the authenticity can be determined by a playback device having a simple structure.

Next, a third embodiment of the present invention will be described. FIG. 7A is a plan view schematically showing a state of the information recording medium according to the third embodiment of the present invention when no voltage is applied, and FIG. 7B is a side view thereof. FIG. 8 is a plan view schematically showing a state of the information recording medium shown in FIGS. 7A and 7B when a voltage is applied.

The information recording medium 10 shown in FIG. 7 and FIG.
For example, it is a personal authentication card such as an employee card. The personal authentication card 10 has a base material 11 for recording information made of plastic or the like, and on one main surface thereof,
An image 21 such as a photograph of the person himself / herself and characters 22 such as an employee number, a name, an issue date, and an expiration date are printed. The print pattern composed of the image 21 and the characters 22 is formed using an ink containing a color material that does not cause a color change even when an electric field is applied, that is, an ordinary ink conventionally used. .

On the surface of the base 11 on which the image 21 and the characters 22 are printed, a logo mark 29 constituting a security image is further printed. The logo mark 29 is a print pattern 1 used as a security window.
2 is covered. Note that the logo mark 29 is formed using an ink containing a color material that does not change color even when an electric field is applied. The printing pattern 12 is formed by a printing method using an ink containing a coloring material that changes color by the action of an electric field. At least one of the coloring materials is an electric field-sensitive liquid crystal. The liquid crystal microcapsules 13 include a mixture of a material and a dichroic dye in a transparent thin film. A transparent resin film or the like is adhered to a surface of the base material 11 on which the image 21, the character 22, the logo mark 29, and the print pattern 12 are formed as a protective film 23 for protecting them.

The print pattern 12 can be formed, for example, using an ink containing the liquid crystal microcapsules 13 manufactured by the following method. First, LIX manufactured by Chisso Corporation, which is a nematic liquid crystal having a positive dielectric anisotropy.
80 parts by weight of ON-5065xx, 1 part by weight of a black dichroic dye S-435 manufactured by Mitsui Chemicals, 7 parts by weight of a hydrophilic methyl methacrylate monomer, and 7 parts by weight of a hydrophobic isobutyl methacrylate. And 1 part by weight of ethylene glycol dimethacrylate as a crosslinking agent and 0.2 part by weight of benzoyl peroxide are mixed and dissolved.
The mixture thus prepared is dispersed by a homogenizer in a mixture of 3 parts by weight of polyvinyl alcohol and 300 parts by weight of pure water to obtain an emulsion.

This emulsion was heated at a temperature of 85 ° C., 500
The above monomer component is polymerized by stirring at a stirring speed of rpm for 1 hour. After 1 hour, the mixture was filtered through a filter having a pore size of 1 μm, and washed three times with pure water to obtain an average particle size of 6 μm.
A μm liquid crystal microcapsule 13 is obtained.

An ink is prepared by dispersing the thus prepared liquid crystal microcapsules 13 in a 5% dispersion of vinyl acetate fine particles having an average particle size of 0.5 μm so that the concentration becomes 10%. . The print pattern 12 is
It can be formed using the ink obtained as described above.

As shown in FIG. 7A, in the personal authentication card 10, the print pattern 12 constituting the security window is usually in a colored state.
The logo mark 29 covered with the print pattern 12 is invisible or difficult to identify. On the other hand, the playback device 30 shown in FIG.
When a voltage is applied to the print pattern 12 by using the print pattern 12, the amount of light absorbed by the print pattern 12 forming the security window is reduced. As shown in FIG.
The logo mark 29 covered with 2 comes out. As described above, it is also possible to perform the authenticity determination using the print pattern 12 as an optical shutter.

In the first to third embodiments described above,
The color change of the print pattern was used to determine the authenticity of the information recording medium. In contrast, in the fourth and fifth embodiments described below, a change in the dielectric constant of a print pattern is used for determining whether the information recording medium is true or false.

The liquid crystal molecules have a property that the dielectric constant varies depending on the alignment direction which is the direction of the average molecular axis, so-called dielectric anisotropy. In the fourth embodiment, a printing pattern is formed using a color material having the dielectric anisotropy and a normal color material having no dielectric anisotropy. First, the principle used in the fourth embodiment will be described. FIG.
(A)-(c) is a figure which shows roughly the alignment state at the time of the electromagnetic field non-action of the liquid crystal molecule in the liquid crystal microcapsule used by 4th Embodiment of this invention, respectively.
The liquid crystal microcapsules 13 shown in FIGS. 9A to 9C constitute a printing pattern formed on the base material, and in the drawing, the horizontal direction is a direction parallel to the main surface of the base material. It is drawn as

FIGS. 10A to 10D are schematic diagrams for explaining the principle used in the fourth embodiment of the present invention. 10A to 10D, the left side shows the alignment state of the liquid crystal molecules when no electromagnetic field is formed, and the right side shows the alignment state of the liquid crystal molecules when the electromagnetic field is formed. Also, reference number 4
Numeral 0 indicates an information recording medium, reference numerals 44 and 45 indicate electrodes for generating a dielectric constant distribution in a printed pattern containing the liquid crystal microcapsules 13 and a normal colorant, and reference numerals 46 and 47 indicate the dielectric constant. The electrode for reading a rate distribution is shown. In FIGS. 10A and 10C, the electrodes 44 and 45 for generating the dielectric constant distribution also serve as the electrodes 46 and 47 for reading.

The liquid crystal microcapsules 13 shown in FIGS. 9 (a) to 9 (c) apply
2 is included. The dielectric constant of the liquid crystal microcapsules 13 changes depending on the alignment state of the liquid crystal molecules 41, and the alignment state of the liquid crystal molecules 41 when no electromagnetic field is applied depends on the liquid crystal alignment regulating direction of the coating 42.

For example, when the film 42 has a liquid crystal alignment regulating force along the film surface, the liquid crystal molecules 41 usually have the shape shown in FIG.
As shown in (a), it is almost uniformly oriented parallel to the main surface of the substrate 11. That is, a bipolar orientation state parallel to the main surface of the substrate 11 is obtained.

When an electromagnetic field is applied from the outside, the difference ΔΔ between the dielectric constant in the major axis direction and the dielectric constant in the end axis direction of the liquid crystal molecules is obtained.
Liquid crystal molecules with a positive ε are oriented so that the long axis direction is parallel to the direction of the electromagnetic field, while liquid crystal molecules with a negative εε are aligned so that the short axis direction is parallel to the direction of the electromagnetic field. I do.

Therefore, when the liquid crystal molecules 41 take the alignment state shown in FIG. 9A when no electromagnetic field is formed, a liquid crystal material having a positive Δε is used, and the electromagnetic field is applied vertically to the main surface of the base material 11 to make the dielectric If a structure for generating the rate distribution is adopted, FIG.
The alignment state of the liquid crystal molecules can be changed as shown in FIG. When the liquid crystal molecules 41 assume the alignment state shown in FIG. 9A when no electromagnetic field is formed, a liquid crystal material having a negative Δε is used, and an electromagnetic field is applied in parallel to the main surface of the base material 11 to reduce the dielectric constant distribution. FIG. 10
As shown in (b), the alignment state of the liquid crystal molecules can be changed. It is easy to set the direction of the electromagnetic field to a direction perpendicular to the main surface of the base material 11 as shown in FIG. 10A, but when the magnetic field is applied in a non-contact manner, FIG.
May be parallel to the main surface of the substrate 11 as shown in FIG.

When the film 42 has a liquid crystal alignment regulating force perpendicular to the film surface, the liquid crystal molecules 41 are almost uniformly perpendicular to the main surface of the substrate 11 as shown in FIG. (Axial alignment state) or FIG.
As shown in (c), they are arranged radially (they are in a radial alignment state). When the liquid crystal molecules 41 take such an alignment state when an electromagnetic field is not formed, a structure in which a liquid crystal material having a negative Δε is used and a magnetic field is applied perpendicularly to the main surface of the base material 11 to generate a dielectric constant distribution may be adopted. For example, as shown in FIG. 10C, the alignment state of the liquid crystal molecules can be changed. When the liquid crystal molecules 41 take an axial or radial alignment state when no electromagnetic field is formed, a dielectric material is generated by applying an electromagnetic field in parallel to the main surface of the substrate 11 using a liquid crystal material having a positive Δε. Fig. 1
The orientation state of the liquid crystal molecules can be changed as shown in FIG.

Accordingly, any one of the configurations shown in FIGS. 10A to 10D is appropriately adopted according to the alignment state of the liquid crystal molecules 41 when the electromagnetic field is not formed, and the base material of the liquid crystal microcapsules 13 when the electromagnetic field is not formed. If the dielectric constant in the direction perpendicular to the main surface of the colorant 11 and the dielectric constant of a normal color material (having no dielectric anisotropy) are made to substantially match, the dielectric constant is obtained only when a predetermined electromagnetic field is applied. A rate distribution can be generated.

Such a dielectric constant distribution can be read according to the principle shown in FIG. FIGS. 11 (a) to 11 (c)
It is a figure which shows roughly the principle which reads the permittivity distribution used by the authenticity determination method concerning the 4th Embodiment of this invention, respectively. In each of FIGS. 11A to 11C, reference numeral 48 indicates a waveform obtained by reading a dielectric constant distribution. In addition, FIG.
In each of (c), the reading electrodes 46 and 4
Reference numeral 7 also serves as electrodes 44 and 45 for generating a dielectric constant distribution.

As shown in FIG. 11A, the electrodes 46, 4
When the electrode 15 is brought into contact with a printing pattern containing the liquid crystal microcapsules 13 and the normal color material 43 while scanning while applying a predetermined voltage between 7, the permittivity of the normal color material 43 does not change. On the other hand, the dielectric constant of the liquid crystal microcapsule 13 between the electrodes 46 and 47 changes from the normal state. Therefore, the liquid crystal microcapsules 13 and the ordinary color material 43
Can be observed as a sinusoidal waveform 48 shown in FIG.

Further, as shown in FIG.
At least one of 6, 47 may be in the form of a matrix. The dielectric constant distribution according to the liquid crystal microcapsules 13 and the ordinary color material 43 can be observed as a rectangular waveform 48 shown in FIG.

Further, as shown in FIG. 11 (c), the dielectric constant distribution may be read as an electrostatic charge distribution by scanning the printed pattern and the electrode 47 apart from each other.
In this case, a high signal level can be realized by introducing an electrostatic charge to the print pattern surface by corona discharge or the like before reading.

As described above, in each of FIGS. 11 (a) to 11 (c), the reading electrodes 46 and 47 also serve as the electrodes 44 and 45 for generating the dielectric constant distribution. this is,
For example, the waveform of the electric field for generating a dielectric constant distribution is a high-voltage and direct-current or low-frequency waveform, and the waveform of the electric field for reading is a low-voltage and high-frequency waveform.
This can be realized by simultaneously applying a voltage for generating distribution and a voltage for reading in between, that is, superimposing the waveform of the electric field for reading on the waveform of the electric field for generating distribution. FIG. 12 shows an example.

FIG. 12A is a graph showing an example of a voltage waveform for generating a dielectric constant distribution, and FIG. 12B is a graph showing a voltage waveform for generating a dielectric constant distribution shown in FIG. 7 is a graph showing an example of a waveform obtained by superimposing a waveform of an electric field for reading on a graph. In the figure, the horizontal axis indicates time, and the vertical axis indicates voltage. If a voltage having a waveform as shown in FIG. 12B is applied between the electrodes 46 and 47, the electrodes 44 and 45 become unnecessary.

As described above, in the present embodiment, a print pattern is formed using the first color material having the dielectric anisotropy and the second color material having no dielectric anisotropy. Then, the dielectric constant of the first coloring material and the dielectric constant of the second coloring material in a normal state are made substantially equal. Therefore, a dielectric constant distribution does not occur in a state where no electromagnetic field is applied, and a dielectric constant distribution is generated by applying a predetermined electromagnetic field, and this dielectric constant distribution disappears by removing the electromagnetic field. Therefore, more excellent forgery prevention can be realized as compared with the case where a print pattern is simply formed using a plurality of coloring materials having different dielectric constants from each other.

In this embodiment, the print pattern formed by the first color material having the dielectric anisotropy and the second color material having no dielectric anisotropy has, for example, the structure shown in FIG. Can be provided.

FIG. 13A is a diagram schematically showing an example of a print pattern on an information recording medium according to the fourth embodiment of the present invention, and FIG. 13B is a diagram showing the fourth embodiment of the present invention. FIG. 5 is a drawing schematically showing another example of the print pattern of the information recording medium according to (1). As shown in FIG. 13A, the print pattern 12 includes a liquid crystal microcapsule 13 which is a first color material having a dielectric anisotropy and a second color material 43 having no dielectric anisotropy. Have a juxtaposed structure, or FIG.
As shown in (b), when the liquid crystal microcapsules 13 are embedded in a part of the surface of the layer formed by the second color material 43, the reproduction quality of the dielectric constant distribution is improved.

By using the principle described above, the information recording medium shown in FIG. 14 can be realized. Figure 1
FIG. 4A is a plan view schematically showing an example of an information recording medium according to a fourth embodiment of the present invention, and FIG. 14B is a cross-sectional view along the line EE. The information recording medium 40 shown in FIG. 14 is a personal authentication card such as an employee card, for example. The personal authentication card 40 has an information recording base material 11 made of plastic or the like, and on one main surface thereof, an image 21 such as a face photograph of the person, an employee number, a name, Characters 22 such as due date and expiration date
Is printed. The print pattern composed of the image 21 and the characters 22 is formed using an ink containing a color material that does not cause a color change even when an electric field is applied, that is, an ordinary ink conventionally used. .

The substrate 11 is provided with a rectangular opening, into which a light-reflective electrode 46 is fitted. On the electrode 46, a printing pattern 52 constituting a security image is formed as a barcode pattern. This print pattern 52 is formed using an ink containing the liquid crystal microcapsules 13. A transparent resin film or the like is adhered to a surface of the base material 11 on which the image 21, the character 22, and the print pattern 52 are formed, as a protective film 23 for protecting them.

The print pattern 52 can be formed, for example, by using an ink containing the liquid crystal microcapsules 13 produced by the following method. First, ZLI manufactured by Merck, which is a nematic liquid crystal having a positive dielectric anisotropy.
81 parts by weight of -1840, 7 parts by weight of a hydrophilic methyl methacrylate monomer, 7 parts by weight of a hydrophobic isobutyl methacrylate, 1 part by weight of ethylene glycol dimethacrylate as a cross-linking agent, and 0 parts by weight of benzoyl peroxide. And 2 parts by weight. The mixture thus prepared is dispersed by a homogenizer in a mixture of 3 parts by weight of polyvinyl alcohol and 300 parts by weight of pure water to obtain an emulsion.

The emulsion was prepared at a temperature of 85 ° C., 500
The above monomer component is polymerized by stirring at a stirring speed of rpm for 1 hour. After 1 hour, the mixture was filtered through a filter having a pore size of 1 μm, and washed three times with pure water to obtain an average particle size of 6 μm.
A μm liquid crystal microcapsule 13 is obtained.

An ink is prepared by dispersing the thus prepared liquid crystal microcapsules 13 in a 5% dispersion of vinyl acetate fine particles having an average particle size of 0.5 μm so that the concentration becomes 10%. . The print pattern 12 is
It can be formed using the ink obtained as described above.

The authenticity determination of the personal authentication card 40 shown in FIG. 14 can be performed by using, for example, the apparatus shown in FIG. FIG. 15A is a perspective view schematically showing an example of a reproducing apparatus used for authenticity determination of the personal authentication card shown in FIG. 14, and FIG. 15B is a perspective view of the apparatus shown in FIG. FIG. 15 is a diagram schematically showing a cross-sectional structure along the FF plane, and FIG.
(C) is a figure which shows roughly the cross-section in the GG plane of the apparatus shown to Fig.15 (a). The playback device 60 shown in FIG.
Is an insertion slot 61 for inserting the personal authentication card 40.
Is provided. In addition, the housing 62 is provided with a display unit 68 that displays information recorded as the print pattern 52 on the personal authentication card 40 as numbers or the like. Inside the housing 62, the AC power supply 16, electrodes 46 and 47 connected to the AC power supply 16, respectively, and a data processing unit 63 connected to the AC power supply 16 and the display unit 68
Is housed.

The authenticity determination of the personal authentication card 40 using the reproducing apparatus 60 is performed by, for example, the following method. First, the personal authentication card 40 is inserted into the insertion port 61 of the playback device 60.
And the printed pattern 52 of the personal authentication card 40 is sandwiched between the electrodes 46 and 47. Next, from the power supply 16 to the electrode 4
The electrode 47 is moved at a speed of 10 cm / sec while applying an AC voltage having a waveform shown in FIG.
As a result, the orientation direction of the liquid crystal molecules 41 in the liquid crystal microcapsules 13 constituting the print pattern 52 between the electrodes 46 and 47 changes, and accordingly, the capacitance between the electrodes 46 and 47 changes.

The data processing unit 63 compares the potential waveform between the electrodes 46 and 47 with the potential waveform of the AC power supply 16 at the same time, and detects a digital signal based on a displacement current from the difference.
This digital signal is converted into sequence information by a predetermined decoding process. The obtained sequence information is displayed on the display unit 68. For example, by comparing the numerical sequence displayed on the display unit 68 with the information printed as the character 22 on the personal authentication card 40, the authenticity of the personal authentication card 40 can be determined.

Further, by using the above-described principle,
The information recording medium shown in FIG. 16 can be realized. FIG. 16A is a plan view schematically showing another example of the information recording medium according to the fourth embodiment of the present invention.
(B) is a cross-sectional view along the line HH. The information recording medium 40 shown in FIG. 16 is a personal authentication card such as an employee card, for example. The personal authentication card 40 has an information recording base material 11 made of plastic or the like, and has an image 2 such as a photograph of the person's face on one main surface thereof.
1 and characters 22 such as an employee number, a name, an issuance date, and an expiration date are printed. The print pattern composed of the image 21 and the character 22 is formed using an ink containing a color material that does not cause a color change even when an electromagnetic field is applied, that is, an ordinary ink conventionally used. .

The substrate 11 is provided with a rectangular opening, into which a light-reflective electrode 46 is fitted. A logo 71 is printed on the electrode 46 using ordinary black ink.
1, a print pattern 52 constituting a security image
Are formed in a pattern that matches the logo mark 71. This printing pattern 52 is formed by the liquid crystal microcapsule 1
This is formed using an ink containing No. 3. A transparent resin film or the like is further adhered to a surface of the base material 11 on which the image 21, the character 22, and the print pattern 52 are formed, as a protective film 23 for protecting them.

The print pattern 52 can be formed, for example, using an ink containing the liquid crystal microcapsules 13 produced by the following method. First, Chixso's LIXON-, a nematic liquid crystal having a positive dielectric anisotropy, is used.
8065 parts by weight of 5065xx, 1 part by weight of a black dichroic dye S-435 manufactured by Mitsui Chemicals, 7 parts by weight of a hydrophilic methyl methacrylate monomer, 7 parts by weight of a hydrophobic isobutyl methacrylate, and crosslinking. 1 part by weight of ethylene glycol dimethacrylate as an agent and 0.2 part by weight of benzoyl peroxide are mixed and dissolved. The mixture thus prepared is dispersed by a homogenizer in a mixture of 3 parts by weight of polyvinyl alcohol and 300 parts by weight of pure water to obtain an emulsion.

The emulsion was heated at a temperature of 85 ° C., 500
The above monomer component is polymerized by stirring at a stirring speed of rpm for 1 hour. After 1 hour, the mixture was filtered through a filter having a pore size of 1 μm, and washed three times with pure water to obtain an average particle size of 6 μm.
A μm liquid crystal microcapsule 13 is obtained.

An ink is prepared by dispersing the thus prepared liquid crystal microcapsules 13 in a 5% dispersion of vinyl acetate fine particles having an average particle size of 0.5 μm so that the concentration becomes 10%. . The print pattern 52 is
It can be formed using the ink obtained as described above.

The authenticity determination of the personal authentication card 40 shown in FIG. 16 can be performed using, for example, the apparatus shown in FIG. FIG. 17A shows the personal authentication card 4 shown in FIG.
FIG. 17B is a perspective view schematically showing an example of a reproducing apparatus used for authenticity determination of 0, and FIG. 17B is a view schematically showing a cross-sectional structure of the apparatus shown in FIG. The playback device 80 shown in FIG. 17 has a housing 82 to which an opening / closing section 83 is attached, and the opening / closing section 83 is provided with a matrix-shaped array electrode 47. A display unit 88 for displaying information recorded as the print pattern 52 on the personal authentication card 40 as numerals or the like is externally attached to the housing 82. In addition, in the housing 82, an inspection table 84 provided with an electrode 46 on the upper side and having a lifting function, a detection unit 85 connected to the electrodes 46 and 47, a data processing unit 86 connected to the detection unit 85,
And an electrostatic gun 87 are housed therein. Note that the plurality of individual electrodes constituting the array electrode 47 are individually connected to the detection unit 85 via lead wires (not shown).

The authenticity judgment of the personal authentication card 40 using the reproducing apparatus 80 is performed by the following method, for example. First, the personal authentication card 40 is placed on the inspection table 84.
Next, the opening / closing unit 83 is closed, and the inspection table 84 is moved downward. Thereafter, with the array electrode 47 grounded, an electrostatic charge is introduced to the surface of the personal authentication card 40 by the electrostatic gun 87.

Next, after the array electrode 47 is opened, the inspection table 84 is raised to bring the personal authentication card 40 into contact with the array electrode 47. After that, the array electrode 47
For each of the individual electrodes constituting the above, the current value flowing by connecting to the counter electrode is integrated. In this way, a charge distribution corresponding to the position of each individual electrode is obtained.

Next, for example, the position where the charge amount is equal to or greater than the predetermined threshold value is black, and the position where the charge amount is less than the threshold value is white, and the charge amount distribution obtained by the above-described method is displayed on the display unit 88.
To be displayed. The authenticity of the personal authentication card 40 can be determined based on whether or not the image displayed on the display unit 88 matches the logo mark 71 printed with normal black ink.

Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, a printing pattern containing liquid crystal microcapsules is provided as a color material that causes a change in dielectric constant by applying an electromagnetic field to an information recording base material as in the fourth embodiment. In addition, an electrode pattern is provided on the information recording substrate such that at least a part of the electrode pattern is interposed between a part of the print pattern and the information recording substrate. That is, in the present embodiment, the print pattern containing the liquid crystal microcapsules is formed over a region of the information recording base material where the electrode pattern is formed and a region where the electrode pattern is not formed.

When such a structure is adopted, a change in the dielectric constant can be caused only in the portion of the print pattern located on the electrode pattern. Therefore, the information recorded as the print pattern can be read by forming the dielectric constant distribution between the portion of the print pattern located on the electrode pattern and the other portions.

In the fifth embodiment, the electrode pattern formed on the information recording base material preferably has a continuous shape. In this case, voltage application can be performed at one place. In the fifth embodiment, the liquid crystal microcapsules may be colored with a dichroic dye or the like,
Alternatively, it may not be colored. In the former case, a visible image can be formed using the liquid crystal microcapsules.

In the fourth and fifth embodiments described above, the liquid crystal microcapsules 13 are preferably transparent under normal conditions. In the fourth embodiment,
The liquid crystal microcapsules 13 and the color material 43 having no dielectric anisotropy may exhibit the same color in a normal state. In this case, it is possible to prevent the pattern formed by the liquid crystal microcapsules 13 from being visually identified in a normal state.

In the fourth and fifth embodiments, a liquid crystal microcapsule 13 similar to that used in the first to third embodiments is used as a coloring material that causes a change in dielectric constant by the action of an electromagnetic field. be able to. However, in the present embodiment, a dichroic dye does not need to be used because a dielectric constant change is used instead of a color change.

In the fourth and fifth embodiments, the larger the dielectric anisotropy value (Δε), which is the difference between the dielectric constant in the molecular long axis direction and the dielectric constant in the end axis direction, the larger the recording / reproducing signal. Can be strengthened. Δε is desirably 10 or more.

In the fourth and fifth embodiments, the liquid crystal molecules 41 may not change in the alignment state if the potential level such as triboelectric charge generated during normal use or a commercially available magnet is approached. preferable. That is, it is preferable that the energy required to change the alignment state of the liquid crystal molecules 41 is sufficiently high.

The energy required to change the alignment state of the liquid crystal molecules 41 can be adjusted by appropriately selecting a material. In addition, the liquid crystal microcapsules 13
Can be made non-spherical to change both the alignment state and the operation level of the liquid crystal molecules 41 in the normal state. For example, when the shape of the liquid crystal microcapsules 13 is elongated, the alignment state of the liquid crystal molecules 41 in a normal state becomes stable when the major axis of the liquid crystal molecules is parallel to the longitudinal direction of the liquid crystal microcapsules 13, and the operation level in a direction perpendicular to the longitudinal direction is reduced. improves. In addition, when the shape of the liquid crystal microcapsules 13 is formed into a disk shape, the alignment regulation of the upper and lower bottom surfaces works strongly,
The operation level in the direction perpendicular to this tends to decrease.

To control the operation level of the liquid crystal molecules 41 without affecting other characteristics, it is most effective to change the particle size of the liquid crystal microcapsules 13. The particle size of the liquid crystal microcapsules 13 can usually be changed within a range of less than 1 μm to more than 10 μm, and an operating voltage of several volts to several hundred volts is realized by changing the particle size within such a range. be able to.

In the fourth and fifth embodiments, a method of generating and reading a dielectric constant distribution includes a method of reading all information by applying an electromagnetic field to the entire print pattern including the liquid crystal microcapsules 13. There is a system in which an electromagnetic field is partially applied to read out only the information of that portion. The former method has an advantage that it is simpler than the latter method. On the other hand, the latter method has a lower risk of information being read out by a person who has knowledge of capacitance measurement than the former method. In order to realize a higher security level, for example, the printing pattern containing the liquid crystal microcapsules 13 is made a regular pattern such as a dot pattern, and an electromagnetic field is partially applied to read only the information of that portion. It is also possible to adopt a method of comparing read information with information stored in advance.

In the fourth and fifth embodiments,
When the dielectric constant distribution is repeatedly generated, the alignment state of the liquid crystal molecules 41 may not completely return to the normal state. In such a case, the alignment state of the liquid crystal molecules 41 can be almost completely returned to the normal state by applying a strong electromagnetic field to the main surface of the base material 11 in parallel or perpendicularly.

In the above-described first to fifth embodiments, the description has been given of the case where a color material which causes a color change or a dielectric constant change by applying an electromagnetic field is directly printed on the information recording base material. A printed material such as an adhesive seal, an adhesive sticker, and a sheet with an adhesive is formed by printing a colorant on a film or foil, and the printed material can be attached to an information recording substrate. Such a printed matter can be manufactured by the same method as described in the first to fifth embodiments.

[0120]

As described above, according to the present invention, in order to provide anti-counterfeiting properties, a first color material which changes color or dielectric constant by applying an electric or magnetic field, an electric or magnetic field, A print pattern containing a second color material that does not change the color or the dielectric constant even when is applied.
When such a printing pattern is used, it is possible to make a true / false judgment by an extremely simple method of applying an electric or magnetic field, record different information for each medium, and form a complicated pattern. However, it is impossible to rewrite the recorded information. Therefore, according to the present invention, forgery prevention can be made extremely difficult while imparting anti-counterfeiting properties is easy. That is, according to the present invention, an information recording medium excellent in anti-counterfeiting properties, a printed matter capable of imparting excellent anti-counterfeiting properties to an information recording medium, and a reproducing apparatus that can be used to determine the authenticity of such information recording medium Is provided.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of an information recording medium according to first to third embodiments of the present invention in a state where no voltage is applied, and FIG.
FIG. 3 is a cross-sectional view of the information recording medium according to the first to third embodiments of the present invention in a voltage applied state.

FIG. 2A is a plan view schematically showing an information recording medium according to a first embodiment of the present invention, and FIG. 2B is a side view of the information recording medium shown in FIG.

FIG. 3A is a perspective view schematically showing a reproducing apparatus used for determining the authenticity of an information recording medium according to the first embodiment of the present invention, and FIG. 3B is a perspective view of the reproducing apparatus shown in FIG. Sectional drawing in the AA plane.

FIG. 4A is a plan view schematically showing an information recording medium according to a second embodiment of the present invention, and FIG. 4B is a side view of the information recording medium shown in FIG. FIG. 3C is a cross-sectional view of the information recording medium shown in FIG.

5A is a plan view of an information recording base material used for the information recording medium shown in FIG. 4, and FIG. 5B is a cross-sectional view of the information recording base material shown in FIG. FIG.

6A is a plan view of an intermediate member used for the information recording medium shown in FIG. 4, and FIG. 6B is a plan view of a protective film used for the information recording medium shown in FIG.

FIG. 7A is a plan view schematically showing a state of the information recording medium according to a third embodiment of the present invention when no voltage is applied, and FIG. 7B is a side view of the information recording medium shown in FIG. FIG.

FIG. 8 is a plan view schematically showing a state of the information recording medium shown in FIGS. 7A and 7B when a voltage is applied.

FIGS. 9A to 9C are diagrams schematically illustrating alignment states of liquid crystal molecules in a liquid crystal microcapsule used in a fourth embodiment of the present invention when no electromagnetic field is applied.

FIGS. 10A to 10D respectively show a fourth embodiment of the present invention.
FIG. 2 is a schematic diagram for explaining the principle used in the embodiment.

FIGS. 11A to 11C respectively show a fourth example of the present invention.
The figure which shows roughly the principle which reads the permittivity distribution used by the authenticity determination method which concerns on embodiment of FIG.

12A is a graph showing an example of a waveform of a voltage for generating a dielectric constant distribution, and FIG. 12B is a graph showing a waveform of an electric field for reading as a waveform of a voltage for generating a dielectric constant distribution shown in FIG. 7 is a graph showing an example of a waveform obtained by superimposing.

FIG. 13A is a diagram schematically showing an example of a print pattern of an information recording medium according to a fourth embodiment of the present invention;
(B) is a figure which shows roughly another example of the print pattern of the information recording medium which concerns on 4th Embodiment of this invention.

14A is a plan view schematically showing an example of an information recording medium according to a fourth embodiment of the present invention, and FIG.
Sectional drawing along the EE line of the information recording medium shown in FIG.

15A is a perspective view schematically showing an example of a reproducing apparatus used for authenticity determination of the information recording medium shown in FIG. 14;
(B) is a diagram schematically showing a cross-sectional structure along the FF plane of the device shown in (a), and (c) is a schematic diagram showing a cross-sectional structure along the GG surface of the device shown in (a). FIG.

FIG. 16A is a plan view schematically showing another example of the information recording medium according to the fourth embodiment of the present invention, and FIG. 16B is an HH line of the information recording medium shown in FIG. Sectional view along.

17A is a perspective view schematically showing an example of a reproducing apparatus used for determining the authenticity of the information recording medium shown in FIG. 16;
FIG. 2B is a diagram schematically illustrating a cross-sectional structure of the device illustrated in FIG.

[Explanation of symbols]

10, 40: information recording medium; 11: base material; 12,
52: printing pattern; 13: liquid crystal microcapsules 14, 15, 44, 45, 46, 47: electrodes;
... Power supply 18 ... Arrows; 21 ... Images; 22 ... Characters; 2
3: Protective film 30, 60, 80: Reproducing device; 31, 61: Insertion port 32, 62, 82: Housing: 33: Transparent substrate;
Reference numeral 25: Support plate 25: Intermediate member; 24: True / false judgment part; 26: Concave part 28: Opening part; 29, 71: Logo mark;
... Liquid crystal molecules 42 ... Coatings; 43 ... Coloring materials; 68,88 ... Display units 63,86 ... Data processing units; 83 ... Opening / closing units;
4: Inspection table 85: Detecting unit; 87: Electrostatic gun

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06K 17/00 G06K 17/00 A 5B058 B41J 29/00 Z 19/077 G06K 19/00 K 19/10 R 19/00 W (72) Inventor Katsuyuki Naito 1st Toshiba R & D Center, Komukai-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Yutaka Nakai 1st Toshiba-cho, Komukai-Toshiba-cho, Saisaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Research and Development Center Co., Ltd. (72) Inventor Yuko Gizu 1 at Komukai Toshiba-cho, Yuki-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Research & Development Center Co., Ltd. (72) Inventor Seizaburo Shimizu, Kawasaki-shi, Kanagawa Prefecture No. 1 Komukai Toshiba, Toshiba R & D Center (72) Inventor Masao Tanaka No. 1, Komukai Toshiba, Kochi-ku, Kawasaki, Kanagawa Pref. Inside the Development Center (72) Inventor Hironori Iwanaga 1st address, Komukai Toshiba-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Inside the Toshiba Research and Development Center (72) Inventor Airita Hotta 1st address, Komukai Toshiba-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Shintaro Enomoto, Shintaro Enomoto, Kobayashi-ku, Kawasaki-shi, Kanagawa 1st place, Komukai Toshiba-cho F-term (reference) 2C005 HA02 HB01 JB02 JB11 JC02 JC04 KA06 LB19 LB52 2C061 AP03 AP04 AS12 CL10 2H088 EA62 FA09 GA02 GA10 GA13 HA05 JA06 MA20 2H089 HA06 KA06 KA07 KA09 NA22 QA16 RA06 UA09 5B035 AA13 BA03 BB09 CA01 CA06 5B058 KA12 KA13 KA32 KA37

Claims (10)

[Claims] An information recording base material and a printing pattern provided on the information recording base material, wherein the printing pattern causes a color change by applying an electromagnetic field, An information recording medium comprising: a second color material that does not change color when an electromagnetic field is applied. 2. A method according to claim 1, further comprising an information recording substrate and a printing pattern provided on the information recording substrate, wherein the printing pattern causes a change in dielectric constant by applying an electromagnetic field.
An information recording medium characterized by containing a color material of the formula (1) and a second color material that does not cause a change in dielectric constant by applying the electromagnetic field. 3. The information recording medium according to claim 1, wherein the first color material contains a liquid crystal microcapsule including a liquid crystal material sensitive to an electromagnetic field in a thin film. 4. The information recording medium according to claim 3, wherein the liquid crystal material contains a dichroic dye. 5. A printing material comprising: a printing base material; and a printing pattern formed on the printing base material, wherein the printing pattern includes a first colorant that changes color by applying an electromagnetic field and the electromagnetic field. And a second colorant which does not cause a color change by acting. 6. A printing material comprising: a printing base material; and a printing pattern formed on the printing base material, wherein the printing pattern causes a change in dielectric constant by applying an electromagnetic field, and the first color material and the electromagnetic field And a second colorant that does not cause a change in the dielectric constant by acting on the printed matter. 7. The printed matter according to claim 5, wherein the first coloring material contains a liquid crystal microcapsule containing a liquid crystal material sensitive to an electromagnetic field in a thin film. 8. The printed matter according to claim 7, wherein the liquid crystal material contains a dichroic dye. 9. An information recording substrate, comprising: a first color material that changes color when an electromagnetic field is applied to the first color material; and a printing pattern provided on the information recording substrate. The second that does not cause a color change by acting
A reproduction apparatus for an information recording medium containing a color material according to any one of claims 1 to 3, further comprising: an electromagnetic field forming mechanism for applying an electromagnetic field to the print pattern; and a window for observing the print pattern. 10. An information recording base material, comprising: a first printed pattern provided on the first information recording base material, wherein the printed pattern causes a change in dielectric constant by applying an electromagnetic field.
An apparatus for reproducing an information recording medium containing a color material and a second color material that does not cause a change in dielectric constant by applying the electromagnetic field, wherein an electromagnetic field generating mechanism that applies an electromagnetic field to the print pattern; A reading mechanism for reading an electrical distribution of the dielectric constant of the print pattern as an electric signal by applying an electromagnetic field to the print pattern.