JP2023074288A - Duplication prevention medium - Google Patents

Abstract

To enable discrimination between an original and a duplication by observation with the naked eye under excitation light irradiation.SOLUTION: In a duplication prevention medium, a light-transmitting base material includes a first face and a second face which is a face on an opposite side of the first face. The light-transmitting base material has an ultraviolet absorbing property. The first face includes a plurality of first colored parts and first non-colored parts arranged in an alternating manner. The second face includes a plurality of second colored parts and second non-colored parts arranged in the alternating manner. The first colored part reflects a first reflected light, and the second colored part reflects a second colored light. The first colored part includes a first colored layer containing first color pigment and a first fluorescent pigment that develops color by an excitation light. The second colored part includes a second colored layer containing a second color pigment of a color different from the first colored part, and a second fluorescent pigment.SELECTED DRAWING: Figure 2

Description

The present invention relates to copy protection media.

2. Description of the Related Art As the performance of color copiers has improved in recent years, it has become easier to forge securities such as stock certificates and bonds, as well as various certificates. For this reason, a copy-preventing medium that can be distinguished from copies is sometimes used for these articles.

The anti-copying medium is a recording medium to which anti-counterfeiting technology is applied to prevent or restrain counterfeiting by color copiers and the like. As a copy-preventing medium, for example, a copy obtained by using a color copier displays a pattern such as specific characters or pictures that cannot be seen in the original.

As one anti-counterfeiting technology for anti-copying media, for example, three types of fluorescent inks containing fluorescent pigments emitting R (red), G (green), and B (blue) are used to form a base material for anti-copying media. By printing RGB image data corresponding to the above image, a phosphor image is formed on the base material, and although it is not visible under white light, it is colored as RGB light under excitation light irradiation, and the image is formed by additive color mixing. An image forming method has been proposed in which a corresponding fluorescent image can be visually recognized (see Patent Document 1).

Further, an image is provided on the base material of the anti-copying medium, and the image comprises a first phosphor emitting a first color with a first afterglow time under excitation light irradiation and a second afterglow longer than the first afterglow time. A copy protection medium containing a second phosphor that emits light of a second color over time has also been proposed (see Patent Document 2).

Printed matter on such anti-copying media exhibits a two-stage color change that exhibits a mixed color of the first and second colors and a second color. It is difficult to ensure the security of the light emitted from the image with only a two-stage color change.

JP-A-10-35089 Japanese Patent Application Laid-Open No. 2005-67043

The present invention has been made in consideration of such points, and the color of the image visible under white light, the color of the image on one side visible under irradiation of excitation light, and the image on the other side, which is the back side of the image. To provide a copy-preventing medium with high security that allows an observer to visually recognize changes in the color of the paper and three different colors, thereby enabling the distinction between the original and the copy by observation with the naked eye. and

In the anti-copying medium for solving the above problems, a light-transmitting substrate has a first surface and a second surface opposite to the first surface, and the light-transmitting substrate absorbs ultraviolet rays. having sex,
The first surface comprises a plurality of first colored portions and a plurality of first non-colored portions arranged alternately,
The second surface comprises a plurality of second colored portions and a plurality of second non-colored portions arranged alternately,
In the copy prevention medium, the width of the first non-colored portion and the second non-colored portion is in the range of 5 μm or more and 100 μm or less.

The first colored portion reflects the first colored light, the second colored portion reflects the second colored light, and the first colored portion includes the first colored pigment and the first fluorescent pigment that is colored by the excitation light. wherein the second colored portion includes a second colored pigment having a color different from that of the first colored pigment and a second fluorescent pigment having a color different from that of the second fluorescent pigment It is an anti-copying medium with a color layer.

The second colored portion is arranged to face the first non-colored portion with the light-transmissive substrate interposed therebetween, and the second non-colored portion is arranged to face the first colored portion with the light-transmissive substrate interposed therebetween. A copy protection medium characterized by:

When the image area of the authenticity discriminating part in the above copy prevention medium is observed under white light, the original and the copy by the color copier are the first colored part and the second colored part through the transparent base material. An observer visually recognizes the mixed colors, and the original and its copy are indistinguishable by observation with the naked eye.

Therefore, when the image area of the authenticity discriminating portion in the above copy protection medium is observed with the reflected light of the first colored portion of the first surface under excitation light irradiation, the color of the fluorescent colored light of the first colored portion The observer visually recognizes only In the original, since the light-transmitting base material having ultraviolet absorption is interposed, it is not affected by the reflected light of the second colored portion of the second surface, and the second color is not a mixed color. The observer visually recognizes only the color of the fluorescent colored light of one colored portion.

Similarly, when the image area of the authenticity discriminating portion in the above copy protection medium is observed with the reflected light of the second colored portion of the second surface under excitation light irradiation, the fluorescent colored light of the second colored portion is observed. An observer visually recognizes only the color, and is not affected by color mixture due to reflected light from the first colored portion of the first surface.

Since the first fluorescent pigment in the first colored portion and the second fluorescent pigment in the second colored portion are different in color, the color observed from the first surface of the original under irradiation of excitation light in the anti-copying medium and the The colors observed from the second surface are also different.

On the other hand, in a copy made by a color copier, a light-transmitting substrate that does not absorb ultraviolet rays is interposed therebetween, and when observed from the first surface and the second surface under excitation light irradiation, each Affected by color mixture due to reflected light from the reverse side. When the original and the copy are compared, the difference in color observed from the first surface can be visually recognized, and the original and the copy can be distinguished by observation with the naked eye. Similarly, when observing from the second side, the original and the copy can be visually distinguished from each other by visual observation due to the visible color difference.

As described above, the original copy of the anti-copying medium and its copy consist of the image color visible under white light, the image color visible under excitation light irradiation on one side, and the image color on the other side visible under excitation light irradiation. The color of the image is compared with each other and can be distinguished by observation with the naked eye.

The width of the first and second non-colored portions is preferably in the range of 5 μm to 100 μm. If it is less than 5 μm, it is difficult to manufacture. If it is more than 100 μm, the viewer will not recognize the colors of the image visible under white light as a mixed color image, so that the effect of the present invention cannot be obtained sufficiently.

According to still another aspect of the copy preventing medium for solving the above problem, the width of the first non-colored portion and the width of the second non-colored portion may be equal or different. The first non-colored portions may be arranged regularly or may be arranged irregularly. Similarly, the second non-colored portions may be arranged regularly or irregularly.

According to still another aspect of the copy preventing medium for solving the above problems, the second colored portion and the second non-colored portion are formed via the first non-colored portion and the first colored portion, respectively, and the light-transmitting base material. A copy-protective medium is provided according to any of the above opposed sides.

When this configuration is adopted, at least a portion of the second colored portion is visible at the position of the first non-colored portion in the observed image that can be visually recognized when viewed from the first surface of the anti-copying medium. Further, in the observed image viewed from the second surface of the anti-copying medium, at least part of the first colored portion is visible at the position of the second non-colored portion. Therefore, when viewed from the first side or the second side of the anti-copying medium, the above effects can be obtained more reliably.

According to still another aspect of the copy preventing medium for solving the above problems, the width of the first non-colored portion is equal to the width of the second colored portion facing the first non-colored portion via the light-transmissive substrate. smaller compared to
The width of the second non-colored portion is smaller than the width of the first colored portion facing the second non-colored portion via the light-transmitting base material, and the copy prevention medium according to the aspect is provided. be.

When this configuration is adopted, the above effects can be obtained more reliably when viewed from the first side or the second side of the anti-copying medium.

According to still another aspect of the copy preventing medium that solves the above problems, the first colored portion and the first non-colored portion have a linear shape and are alternately arranged in the width direction. The second non-colored portion has a linear shape and is arranged alternately in the width direction.

In this anti-copying medium, the first colored portion, the first non-colored portion, the second colored portion, and the second non-colored portion may have a linear shape. Alternatively, the first colored portion, the first non-colored portion, the second colored portion, and the second non-colored portion may include curved portions. Alternatively, the first colored portions may form a nested array pattern, and the second colored portions may form a nested array pattern corresponding to the first colored portions.

In these cases, the widths of the first and second colored portions may be constant along the length of the line, or may vary. Adjacent first colored portions may have the same width or may have different widths.

The width of the first non-colored portion may be constant along the length direction of the line, or may vary. Moreover, the widths of the plurality of first non-colored portions may be equal or different. Similarly, the width of the second non-colored portion may be constant along the length of the line, or may vary. Also, the widths of the plurality of second non-colored portions may be equal or different.

Alternatively, according to still another aspect of the copy preventing medium for solving the above problems, the first colored portion and the first non-colored portion are arranged in a checkered pattern, and the second colored portion and the second non-colored portion are arranged. A copy-protective medium according to any of the above aspects arranged in a checkerboard pattern is provided.

The light-transmissive base material has visible light transmittance. The light-transmitting substrate is preferably colorless and transparent or colorless and translucent. For example, a light-transmissive substrate transmits incident light without coloration when illuminated with white light.

1 is a plan view schematically showing a copy protection medium according to one embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view showing an enlarged part of the copy protection medium shown in FIG. 1; FIG. 2 is an enlarged plan view showing a portion of the first surface of the copy protection medium shown in FIG. 1; The top view which expands and shows a part of 1st surface shown in FIG. FIG. 2 is an enlarged plan view showing a portion of the second surface of the copy protection medium shown in FIG. 1; The top view which expands and shows a part of back surface shown in FIG. FIG. 2 schematically shows an example of observation when the first surface of the copy protection medium shown in FIG. 1 is illuminated with white light; FIG. 8 shows an image displayed by the anti-copying medium shown in FIG. 1 under the conditions of FIG. 7; FIG. 2 schematically shows an example of observation when the second surface of the copy protection medium shown in FIG. 1 is illuminated with white light; 10 shows an image displayed by the anti-copying medium shown in FIG. 1 under the conditions of FIG. 9; FIG. FIG. 2 is a plan view showing an enlarged part of the copy; FIG. 2 schematically shows an observation example when the first surface of the copy protection medium shown in FIG. 1 is illuminated with excitation light; 13 shows an image displayed by the anti-copying medium shown in FIG. 1 under the conditions of FIG. 12; FIG. FIG. 2 schematically shows an observation example when the second surface of the copy protection medium shown in FIG. 1 is illuminated with excitation light; FIG. 15 shows an image displayed by the anti-copying medium shown in FIG. 1 under the conditions of FIG. 14; FIG. 11 is a plan view schematically showing an example of a structure that can be adopted for the first colored layer of the copy protection medium according to the first modified example; FIG. 11 is a plan view schematically showing an example of a structure that can be adopted for the second colored layer of the copy prevention medium according to the first modified example; FIG. 11 is a plan view schematically showing an example of a structure that can be adopted for the first colored layer of the copy prevention medium according to the second modified example; FIG. 11 is a plan view schematically showing an example of a structure that can be adopted for the second colored layer of the copy prevention medium according to the second modified example;

Embodiments will be described below with reference to the drawings. Embodiments described below are more specific to any of the above aspects. Elements having the same or similar functions are denoted by the same reference numerals, and overlapping descriptions are omitted.

FIG. 1 is a plan view schematically showing a copy-protection medium according to one embodiment of the solution. FIG. 2 is a cross-sectional view showing an enlarged part of the anti-copying medium shown in FIG. 3 is an enlarged plan view of a portion of the first surface of the copy-protection medium shown in FIG. 1. FIG. 4 is a plan view showing an enlarged part of the first surface shown in FIG. 3. FIG. 5 is an enlarged plan view of a portion of the second surface of the copy-protection medium shown in FIG. 1. FIG. 6 is a plan view showing an enlarged part of the second surface shown in FIG. 5. FIG. In each figure, the X direction and the Y direction are directions parallel to the display surface of the anti-copying medium 1 and perpendicular to each other, and the Z direction is a direction perpendicular to the X direction and the Y direction, that is, It is the thickness direction of the anti-copying medium 1 .

The copy protection medium 1 shown in FIG. 1 is a gift certificate. The anti-copying medium 1 may be securities other than gift certificates. Alternatively, copy protection medium 1 may be a certificate or identification card, such as an identification card.

The anti-copying medium 1 includes a light transmissive substrate 11, first colored layer 12 and second colored layer 13 shown in FIG. 2, and a printed layer 14 shown in FIG.

A polymer film can be used for the light-transmissive substrate 11 . Polymer films include resins with high light transmittance such as polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene (PE), and triacetyl cellulose (TAC). is preferred. An appropriate material is selected for the light-transmitting base material 11 according to the use of the anti-copying medium. Here, as an example, the light transmissive base material 11 is assumed to be a colorless and transparent polymer film.

The light transmissive substrate 11 has a rectangular shape with long sides parallel to the X direction. The light transmissive substrate 11 may have other shapes.

When the light transmissive substrate 11 is a polymer film, the total light transmittance is preferably 87% or more and 93% or less. There is no upper limit for the total light transmittance, but considering the refractive index of the polymer film, it is difficult to obtain a polymer film with a total light transmittance higher than 93% in terms of manufacturing. Here, the "total light transmittance" is a value obtained by the method defined in JISK7375:2008 "Plastics - Determination of total light transmittance and total light reflectance".

When the light transmissive substrate 11 is a polymer film, the haze is preferably 4% or less. There is no lower limit for haze, but it is usually 0.1% or more. Here, "haze" is a value obtained by the method specified in JISK7136:2000 "Plastics - Determination of haze of transparent materials".

Moreover, the light-transmitting base material 11 has ultraviolet absorption. There is no particular limitation on the method of imparting ultraviolet absorbency, and a method of adding an ultraviolet absorber to the resin material of the light-transmitting substrate 11, a method of impregnating the film-formed light-transmitting substrate 11, and a film-forming light transmission method. For example, a method of coating on the flexible base material 11 is used.

Examples of the method of coating the film-formed light-transmitting substrate 11 include a method of coating a dispersion containing an ultraviolet absorber using a dip coater, a die coater, a slit coater, a bar coater, a gravure coater, or the like.

When forming by coating, it is preferable to reduce the thickness of the ultraviolet absorbing layer. The thickness of the ultraviolet absorbing layer is preferably 0.01 μm or more and 1,000 μm or less, more preferably 0.02 μm or more and 500 μm or less. If the thickness is less than 0.01 μm, the ultraviolet absorption amount may be insufficient, and if it exceeds 1,000 μm, the transmittance of visible light may decrease. The content of the ultraviolet absorber in the ultraviolet absorbing layer varies depending on the ultraviolet absorber used and cannot be generally specified, but the content that provides an ultraviolet transmittance that does not impair the effect of the copy-preventing medium is appropriately selected. Select is preferred.

The ultraviolet absorber is not particularly limited and can be appropriately selected depending on the purpose. Examples include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, A cyanoacrylate-based ultraviolet absorber and the like can be mentioned. These may be used individually by 1 type, and may use 2 or more types together.

Examples of commercially available light-transmissive substrates 11 having ultraviolet absorption properties include ultraviolet-absorbing PET films such as Tetoron films manufactured by Teijin.

The light transmissive substrate 11 has a first surface and a second surface opposite to the first surface. The first surface and the second surface are the upper surface and the lower surface of the light transmissive substrate 11 in FIG. 2, respectively.

The first colored layer 22 provided on the first surface of the light transmissive substrate 11 is composed of a plurality of first colored portions 121 and first non-colored portions 122 arranged alternately on the first surface. The first colored portion 121 includes a first colored pigment and a first fluorescent pigment, reflects the first colored light with the first colored pigment when illuminated with white light, and reflects the first colored light when illuminated with excitation light. The first fluorescent pigment reflects the first fluorescent colored light. When illuminated with white light from the first surface, the first non-colored portion 122 transmits the white light without coloring it, and when illuminated with excitation light, the ultraviolet absorption of the light-transmitting substrate 11 causes the second non-colored portion 122 to pass through. Suppresses permeation to the surface. According to one example, the first non-colored portion 122 is the space sandwiched between the first colored portions 121 . According to another example, the first non-colored portions 122 are made of a colorless transparent material that fills the gaps between the first colored portions 121 .

The second colored layer 23 provided on the second surface of the light transmissive substrate 11 includes a plurality of second colored portions 131 and second non-colored portions 132 alternately arranged on the second surface. The second colored portion 131 contains a second colored pigment that is different in color from the first colored pigment and a second fluorescent pigment that is different in color from the first fluorescent pigment. The second colored light is reflected by the two colored pigments, and the second fluorescent colored light associated with the second fluorescent pigment is reflected when illuminated with the excitation light. When illuminated with white light from the second surface, the second non-colored portion 132 transmits the white light without coloring it. Suppresses permeation to the surface. According to one example, the second non-colored portion 132 is the space sandwiched between the second colored portions 131 . According to another example, the second non-colored portions 132 are made of a colorless transparent material that fills the gaps between the second colored portions 131 .

The thickness of the first colored portion 121 and the second colored portion 131 is preferably 0.3 μm or more. If the thickness of the first colored portion 121 and the second colored portion 131 is less than 0.3 μm, the adhesion to the light transmissive substrate 11 may become insufficient.

The first colored portion 121 and the second colored portion 131 can be formed by printing. For example, first, the first colored portion 121 is formed on the first surface of the light transmissive substrate 11 by printing. Next, alignment is appropriately performed, and the second colored portion 131 is formed on the second surface of the light transmissive substrate 11 by printing. The order of printing may be from the second coloring section 131 . The printing method is selected from known printing methods such as screen printing, screen offset printing, gravure printing, gravure offset printing, flexographic printing, and reversal printing. Select accordingly.

The first colored portion 121 and the second colored portion 131 that are visible under white illumination may contain a color pigment and a polymer. As color pigments, organic pigments, inorganic pigments, or combinations thereof known in the art can be used.

Inorganic pigments include metals; oxides typified by titanium dioxide, zinc white, and iron black; hydroxides; sulfides; selenides; ferrocyanides; phosphate; and carbon. Organic pigments include carbon compounds, nitroso-based compounds; nitro-based compounds; azo-based compounds; lake-based pigments, phthalocyanine-based compounds, condensed polycyclic materials, and the like.

Polymers consist of colorless and transparent resins or colored resins. Examples of resins include polycarbonate resins, acrylic resins, fluorine acrylic resins, silicone acrylic resins, epoxy acrylate resins, polystyrene resins, acrylonitrile-styrene resins, cycloolefin polymers, methylstyrene resins, fluorene resins, polyethylene terephthalate (PET ), polypropylene, phenolic resin, melamine resin, polyethylene naphthalate (PEN), and polyimide (PI).

Thermoplastic resins include polyethylene terephthalate (PET), polycarbonate (PC), polystyrene (PS), cyclic olefin copolymer (COC), acrylic resins such as polymethyl methacrylate (PMMA), cycloolefin polymer (COP), methacrylic acid • Styrene copolymer (MS), acrylonitrile-styrene copolymer (AS), polyethylene naphthalate (PEN), and polyimide (PI) can be used. As thermosetting resins, thermosetting resins well known in the art such as phenolic resins, melamine resins, epoxy resins, and alkyds can be used.

Besides these, engineering plastics and super engineering plastics such as polybutylene terephthalate (PBT), polyoxymethyl (POM), polyamide (PA), and polyphenylsulfide (PPS) can also be used as resins. . In addition, it is possible to use resins that are cured by ionizing radiation, such as acrylic resins, urethane resins, epoxy resins, polyester resins, and thiol resins.

The first coloring part 121 and the second coloring part 131 may further include light scattering particles. Spherical particles or irregularly shaped particles are used as the light scattering particles. The material of the light scattering particles may be either organic or inorganic.

Organic materials that can be used for the light scattering particles include, for example, acrylic resins, polystyrene, styrene-acrylic copolymers or crosslinked products thereof, melamine-formalin condensates, urethane resins, polyesters, silicone resins, fluorine particles, epoxy resins, and these. is a copolymer of Inorganic materials that can be used for light scattering particles include, for example, clay compounds such as smectite, kaolinite, and talc; inorganic oxides such as silica, titania, alumina, silica-alumina, zirconia, zinc oxide, barium oxide, and strontium oxide; inorganic carbonates such as calcium carbonate, barium carbonate, magnesium carbonate, and strontium carbonate; inorganic chlorides such as barium chloride and strontium chloride; inorganic sulfates such as barium sulfate and strontium sulfate; inorganic nitrates such as barium nitrate and strontium nitrate; inorganic hydroxides such as barium hydroxide, aluminum hydroxide, and strontium hydroxide; and glass.

The first colored portion 121 and the second colored portion 131, which are visible under ultraviolet irradiation, fluoresce with a fluorescent pigment. As the phosphor used for the fluorescent pigment, either an inorganic phosphor or an organic phosphor can be selected depending on the color to be emitted. Examples of inorganic phosphors that emit red light include Y ₂ O ₃ :Eu, YVO ₄ :Eu, 3.5MgO, 0.5 mgF, ₂ GeO ₂ :Mn, (Y,Gd)Bo ₃ :Eu, Y (P, V) O ₄ :Eu and the like. Examples of inorganic phosphors that emit green light include ZnO: Zn, Zn ₃ SiO ₂ :Mn, Zn ₃ S: Cu, Al, (Zn, Cd)S: Cu, Al, ZnS: Cu, Au, Al , _Zn2SiO4 :Mn, ZnS:Ag _, Cu, (Zn,Cd)S _: Cu, ZnS: _Cu , Gd2O2 _: Tb, La2O2S:Tb _{, Y2SiO5} :Ce, _Tb , _Zn2GeO4 :Mn, _CeMgAl11O13 :Tb, _SrGa2S4 : _Eu2 + _, ZnS:Cu, _CO , _MgO.nB2O3 :Ce, Tb, _LaOBr :Tb, Tm _{, La2O2S} :Tb, ZnS:Cu(Mn), and the like. Examples of _inorganic phosphors that emit blue light include ZnS:Ag, _CaWO4 , _Y2SiO5 : _Ce , ZnS:Ag, Ga, Cl, _Ca2B5O3Cl : _Eu2 +, and BaMgAl1 _{. 4O23} : _Eu2 +, _Sr3 ( _PO2 ) _3Cl :Eu and _the like.

On the other hand, examples of organic phosphors include diaminostilbene disulfonic acid derivatives, imidazole derivatives, coumarin derivatives, triazole, carbazole, pyridine, naphthalic acid, derivatives such as imidazolone, dyes such as fluorescein and eosin, and benzene rings such as anthracene. compounds and the like.

The ink used to form the first colored portion 121 and the second colored portion 131 may further contain a solvent in addition to the above components. Solvents are, for example, dodecane or tetradecane. Other compounds or compositions may be used as solvents. For example, in quick-drying inks, solvents such as methyl ethyl ketone (MEK), ethanol, and acetone, which have a low boiling point and are volatilized at room temperature, can be used as solvents. Water-based inks can use water (purified water) as a solvent. Oil-based inks can use oils that are difficult to volatilize at room temperature, such as aliphatic hydrocarbons, glycol ethers, and higher alcohols, as solvents.

The printed layer 14 is provided on the first surface of the light transmissive substrate 11 . The print layer 14 displays, for example, characters, patterns, graphics, photographs, or a combination thereof.

The printed layer 14 can be further provided on the second surface of the light transmissive substrate 11 . Alternatively, the printed layer 14 can be provided on the second surface of the light transmissive substrate 11 instead of on the first surface. Alternatively, the print layer 14 can be omitted.

The print layer 14 has a window W, which is an opening, as shown in FIG. A portion corresponding to the window W of the anti-copying medium 1 is an authenticity discriminating section used for discriminating the authenticity of the anti-copying medium 1 .

The first surface of the light transmissive substrate 11 has, at the position of the window W, a first printed area R1A and a first non-printed area R1B shown in FIGS. On the other hand, the second surface has, at the position of the window W, a second print area R2A and a second non-print area R2B shown in FIGS.

Here, the first print area R1A is formed of a first colored portion and a first non-colored portion, and has a pattern corresponding to the character string "COPY". The first non-printing area R1B is an area other than the first printing area R1A. Also, here, the second print area R2A is a pattern corresponding to the mirror image of the character string "COPY", and the second non-print area R2B is an inverted pattern thereof.

The first colored layer 12 is provided at the position of the window W on the first surface of the light transmissive base material 11 . The first colored layer 12 is not provided on the first non-printing region R1B shown in FIGS. 2 and 3, but is provided on the first printing region R1A.

The first colored layer 12 includes first colored portions 121 and first non-colored portions 122 alternately arranged on the first surface, as shown in FIGS. The first colored portions 121 and the first uncolored portions 122 each have a linear shape and are alternately arranged in the width direction. Here, the first colored portions 121 and the first uncolored portions 122 each have a shape extending in the X direction and are alternately arranged in the Y direction.

The first colored portion 121 reflects the first colored light when illuminated with white light. The first colored portion 121 is formed from ink containing a first colored pigment, a first fluorescent pigment, and a polymer.

A width W1a of the first colored portion 121 is constant along the length direction of the first colored portion 121 . Adjacent first colored portions 121 have the same width W1a. The width W1a is in the range of 5 μm or more and 100 μm or less.

When illuminated with white light, the first non-colored portion 122 transmits the white light without coloring it. Here, the first non-colored portion 122 is the space between adjacent first colored portions 121 .

A width W1b of the first uncolored portion 122 is constant along the length direction of the first uncolored portion 122 . Adjacent first non-colored portions 122 have the same width W1b.

The width W1b is in the range of 5 μm or more and 100 μm or less. Here, the width W1b is smaller compared to the width W1a. The sum of the width W1a and the width W1b is the pitch P1 of the arrangement of the first colored portions 121 or the first non-colored portions 122 .

The second colored layer 13 is provided at the position of the window W on the second surface of the light transmissive base material 11 . The second colored layer 13 is not provided on the second non-printing region R2B shown in FIGS. 2 and 5, but is provided on the second printing region R2A.

The second colored layer 13 includes, as shown in FIGS. 2 and 6, second colored portions 131 and second non-colored portions 132 alternately arranged on the second surface. The second colored portions 131 and the second uncolored portions 132 are alternately arranged on the second surface corresponding to the first colored portions and the first uncolored portions. The second colored portions 131 and the second uncolored portions 132 each have a linear shape and are alternately arranged in the width direction. Here, the second colored portions 131 and the second uncolored portions 132 each have a shape extending in the X direction and are alternately arranged in the Y direction.

The second colored portion 131 reflects the second colored light when illuminated with white light. The second colored portion 131 is formed of ink containing a second colored pigment different in color from the first colored light, a second fluorescent pigment, and a polymer.

The width W2a of the second colored portion 131 is constant along the length direction of the second colored portion 131 . In addition, adjacent second colored portions 131 have the same width W2a.

The width W2a is in the range of 5 μm or more and 100 μm or less. Here, width W2a is equal to width W1a.

When illuminated with white light, the second non-colored portion 132 transmits the white light without coloring it. Here, the second non-colored portion 132 is the space between the adjacent second colored portions 131 .

A width W2b of the second uncolored portion 132 is constant along the length direction of the second uncolored portion 132 . Adjacent second non-colored portions 132 have the same width W2b.

The width W2b is in the range of 5 μm or more and 100 μm or less. Here, width W2b is smaller compared to width W2a. Also, here, the width W2b is equal to the width W1b. The sum of the width W2a and the width W2b is the pitch P2 of the arrangement of the second colored portions 131 or the second non-colored portions 132 .

As shown in FIG. 2, the second colored portion 131 faces the first non-colored portion 122 with the light transmissive substrate 11 interposed therebetween. Also, the first colored portion 121 faces the second non-colored portion 132 with the light transmissive substrate 11 interposed therebetween. In orthogonal projection onto a plane parallel to the first surface, the centerline of each second colored portion 131 coincides with the centerline of the first uncolored portion 122 facing the second colored portion 131. . Also, in this orthogonal projection, the center line of each first colored portion 121 coincides with the center line of the second non-colored portion 132 facing the first colored portion 121 .

The original of the anti-copying medium 1 in this solution and the copy 2 made by the color copier are distinguishable by observation with the naked eye. This will be explained below.

FIG. 7 is a diagram schematically showing an example of observing a reflected image displayed by the anti-copying medium 1 shown in FIG. FIG. 8 shows an image displayed by the anti-copy medium 1 shown in FIG. 1 under the conditions shown in FIG.

In FIG. 7, the illumination light IL from the light source LS illuminates the first surface of the copy preventing medium 1 from an oblique direction, and the light source LS and A copy protection medium 1 is placed. Note that the illumination light IL is white light.

Under this condition, the contribution of the second colored layer 13 to the display is small compared to the contribution of the first colored layer 12 to the display. That is, the contribution of the first colored light to the display is greater than the contribution of the second colored light to the display. Therefore, the color of the region corresponding to the character string "COPY" in the image I2 viewed by the observer OB under this condition is viewed as a mixed color closer to the color of the first colored light than the color of the second colored light. be done.

On the other hand, the contribution of the first colored layer 12 to the display is smaller than the contribution of the second colored layer 13 to the display when viewed from the second surface of the anti-copying medium 1 shown in FIG. That is, the contribution of the second colored light to the display is greater than the contribution of the first colored light to the display. Therefore, under this condition, the color of the region corresponding to the inverted character string "COPY" in the image I3 viewed by the observer OB shown in FIG. Perceived as closely mixed colors.

Under the condition that the first colored portion 121 and the second uncolored portion 132, and the first uncolored portion 122 and the second colored portion 131 are printed in a 1:1 relationship, the image area is formed from the first surface. , the contribution of the first colored layer 12 to the display is about the same as the contribution of the second colored layer 13 to the display. As for the contribution, the contribution of the first colored light 12 to the display is about the same. Therefore, the color of the area corresponding to the character string "COPY" in the image I3 viewed by the observer OB is viewed as a mixed color of the same color even when viewed from both sides.

The color of the area corresponding to the character string "COPY" in the image I3 viewed by the observer OB is composed of the first colored portion 121 and the second uncolored portion 132, and the first uncolored portion 122 and the second colored portion 131. The color may be the same or different depending on the proportion of the image area to be viewed, and may be the same or different between the observation from the first side and the second side of the image area.

On the other hand, when observing the copy 2 by the color copying machine under the conditions of FIGS. It is difficult for the naked eye to distinguish the original copy-protective medium 1 and the copy 2 from each other because of the color produced by the visual observation.

FIG. 12 is a diagram schematically showing how a reflected image displayed by the anti-copying medium 1 shown in FIG. 1 is observed under excitation light irradiation. FIG. 13 shows an image displayed by the anti-copying medium 1 shown in FIG. 1 under the conditions of FIG.

In FIG. 12, the illumination light IL' from the excitation light source LS' illuminates the first surface of the anti-copying medium 1 from an oblique direction, and the reflected light RL' emitted from the anti-copying medium 1 is observed by the observer OB. , a light source LS' and a copy protection medium 1 are arranged.

Under this condition, the contribution of the second colored layer 13 to the display is via the light-transmissive substrate 11 to which the ultraviolet absorber is added, so the first colored layer 12 does not contribute to the display. Therefore, the color 15 of the area corresponding to the character string "COPY" in the image I2 viewed by the observer OB under this condition is only the colored light from the first fluorescent pigment.

On the other hand, when a copy 2 containing the same fluorescent pigment as that of the present invention was copied by a color copier and observed under the same conditions as in FIG. Therefore, the influence of the second colored layer 13 contributes to the display of the first colored layer 12 . Therefore, the color of the area corresponding to the character string "COPY" in the image I2 viewed by the observer OB under this condition is colored light obtained by mixing the colors of the first fluorescent pigment and the second fluorescent pigment.

Therefore, the anti-copy medium 1 and the copy 2 can be distinguished from each other by visually observing such a color difference.

The same is true for observation with the excitation light source from the second surface of the anti-copying medium 1 shown in FIG. , it does not contribute to the display of the second colored layer 13 . Therefore, as shown in FIG. 15, the color 16 of the area corresponding to the inversion of the character string "COPY" in the image I3 viewed by the observer OB under this condition is only the colored light from the second fluorescent pigment.

On the other hand, when a copy 2 containing the same fluorescent pigment as that of the present invention was copied by a color copier and observed under the same conditions as in FIG. Therefore, the influence of the first colored layer 12 contributes to the display of the second colored layer 13 . Therefore, the color of the area corresponding to the inversion of the character string "COPY" in the image I3 viewed by the observer OB under this condition is colored light resulting from the mixture of the second fluorescent pigment and the first fluorescent pigment.

Therefore, by visually observing such a color difference, the anti-copy medium 1 and the copy 2 can be distinguished from each other when viewed from either side.

Various variations of the anti-copy medium 1 are possible. For example, in the copy protection medium 1 described above, each of the first colored portion 121, the first uncolored portion 122, the second colored portion 131, and the second uncolored portion 132 has a linear shape, but they are curved. A portion having a shape may be included. For example, each of the first colored portion 121, the first uncolored portion 122, the second colored portion 131, and the second uncolored portion 132 may have a waveform such as a sinusoidal shape. Alternatively, the first colored portion 121, the first uncolored portion 122, the second colored portion 131, and the second uncolored portion 132 may have the following shapes.

FIG. 16 is a plan view schematically showing an example of a structure that can be adopted for the first colored layer of the anti-copying medium 1 according to the first modified example. FIG. 17 is a plan view schematically showing an example of a structure that can be adopted for the second colored layer of the copy preventing medium 1 according to the first modified example.

In FIG. 16, the first colored portions 121 form a nested arrangement pattern. Specifically, the first colored portion 121 forms a concentric pattern.

In FIG. 17 , the second colored portions 131 form a nested arrangement pattern corresponding to the first colored portions 121 . Specifically, the second colored portion 131 forms a concentric pattern such that the second colored portion 131 and the second uncolored portion 132 face the first uncolored portion 122 and the first colored portion 121, respectively. ing.

A copy-preventing medium similar to the above-described copy-preventing medium 1 except for adopting such a configuration also exhibits the above-described effects.

In the copy preventing medium 1 described above, the first colored portions 121 and the first uncolored portions 122 each have a linear shape and are alternately arranged in the width direction. each have a linear shape and are alternately arranged in the width direction. The first colored portion 121, the first uncolored portion 122, the second colored portion 131, and the second uncolored portion 132 may not have a linear shape.

FIG. 18 is a plan view schematically showing an example of a structure that can be adopted for the first colored layer of the copy preventing medium 1 according to the second modified example. FIG. 19 is a plan view schematically showing an example of a structure that can be adopted for the second colored layer of the copy preventing medium 1 according to the second modified example.

In FIG. 18, the first colored portions 121 and the first non-colored portions 122 are arranged in a checkered pattern. In FIG. 20, the second colored portions 131 and the second non-colored portions 132 are arranged in a checkered pattern. The second colored portion 131 and the second uncolored portion 132 face the first uncolored portion 122 and the first colored portion 121, respectively.

A copy-preventing medium similar to the above-described copy-preventing medium 1 except for adopting such a configuration also exhibits the above-described effects.

Specific examples of the present invention are described below.

<Manufacturing of anti-copy media>
(Example 1)
The anti-copy medium 1 described with reference to FIG. 1 was manufactured by the following method. Note that the printed layer 14 is omitted.

First, a Tetoron film manufactured by Teijin was prepared as the light-transmitting substrate 11 . Next, on the first surface of the light-transmissive base material 11, a first coloring is performed by gravure offset printing using ink obtained by kneading a commercially available cyan process ink with a fluorescent pigment that emits B (blue) light. A layer 12 was formed. Each of the width W1a of the first colored portion 121 and the width W1b of the first non-colored portion 122 was set to 20 μm.

After that, the second surface of the light-transmitting substrate 11 is subjected to a second coloring by gravure offset printing using ink obtained by kneading a commercially available magenta process ink with a fluorescent pigment that emits R (red) light. A layer 13 was formed. Each of the width W2a of the second colored portion 131 and the width W2b of the second non-colored portion 132 was set to 20 μm. In the second colored layer 13, the center line of the second colored portion 131 and the center line of the second uncolored portion 132 are aligned with the center of the first uncolored portion 122 in orthogonal projection onto a plane parallel to the second surface. It was formed so as to match the line and the center line of the first colored portion 121 .

(Example 2)
Copy-protective medium 1 was manufactured in the same manner as in Example 1, except for the following items. That is, in this example, the width W1a of the first colored portion 121 was set to 10 μm, and the width W1b of the first non-colored portion 122 was set to 10 μm. The width W2a of the second colored portion 131 was set to 10 μm, and the width W2b of the second non-colored portion 132 was set to 10 μm.

(Example 3)
Copy-protective medium 1 was manufactured in the same manner as in Example 1, except for the following items. That is, in this example, the width W1a of the first colored portion 121 was set to 90 μm, and the width W1b of the first non-colored portion 122 was set to 90 μm. The width W2a of the second colored portion 131 was set to 90 μm, and the width W2b of the second non-colored portion 132 was set to 90 μm.

(Comparative example 1)
Copy-protective medium 1 was prepared in a manner similar to Example 1, with the following exceptions. That is, in this example, the width W1a of the first colored portion 121 was set to 150 μm, and the width W1b of the first non-colored portion 122 was set to 150 μm. The width W2a of the second colored portion 131 was set to 150 μm, and the width W2b of the second non-colored portion 132 was set to 150 μm.

(Comparative example 2)
Copy-protective medium 1 was manufactured in the same manner as in Example 1, except for the following items. That is, in this example, Lumirror manufactured by Toray, which does not have ultraviolet absorption, was used as the light-transmitting substrate 11 .

The dimensions adopted in the anti-copy media 1 according to Examples 1 to 3 and Comparative Examples 1 and 2 are shown in the table below.

<Manufacturing Copies>
Copies 2 were produced by printing the anti-copying media 1 of Examples 1 to 3 and Comparative Examples 1 and 2 on Lumirror films manufactured by Toray Industries, Inc. using an ink-jet color printer.

<Evaluation 1>
Discrimination of colors with the naked eye from the first and second surfaces of the anti-copy media 1 according to Examples 1 to 3 and Comparative Examples 1 and 2 and their copies 2 when illuminated with white light The results are shown in the above table as Rating 1.

<Evaluation 2>
Results of color discrimination with the naked eye from the first and second surfaces of the anti-copy media 1 and their copies 2 according to Examples 1 to 3 and Comparative Examples 1 and 2 when illuminated with excitation light is shown in the above table as a rating of 2.

Evaluation 1 and 2: when the images of the authenticity discriminating portion of the anti-copying medium 1 and the copy 2 are observed with the naked eye, they can be distinguished from each other by the difference in color observed from each other. was rated as "◯", and the rating when they could not be distinguished from each other was rated as "x".

When the anti-copying mediums 1 and copies 2 according to Examples 1 to 3 and Comparative Example 2 were observed under white light, an image was obtained as a mixed color derived from the arrangement of the first colored portion 121 and the second colored portion 131. could be visually recognized, but the difference in color could not be distinguished with the naked eye.

On the other hand, when the anti-copy medium 1 according to Comparative Example 1 and the copy were observed under white light, the width W1a of the first colored portion 121 and the width W2a of the second colored portion 131 were wide enough to be visually recognized, and the stripes were visually observed. The printed image was observed as if it were formed in a shape, and was visually recognized as a printed image consisting of two kinds of single colors rather than mixed colors.

Observation of the anti-copying media 1 according to Examples 1 to 3 under excitation light irradiation resulted from the first colored portion 121 when observed from the first surface and from the second colored portion 131 when observed from the second surface. In the copy 2, the image can be viewed as a mixed color derived from the arrangement of the first colored portions 121 and the second colored portions 131 both when viewed from the first side and when viewed from the second side. was visually recognized and the difference in color could be distinguished with the naked eye.

When observing the anti-copying medium 1 according to Comparative Example 1 under excitation light irradiation, an image was obtained as a single color derived from the first colored portion 121 when observed from the first surface, and from the second colored portion 131 when observed from the second surface. could not be visually recognized, and it was visually recognized as a mixed color in observation on any surface, and the copy prevention medium 1 and the copy 2 could not be distinguished. In the anti-copying medium 1 according to Comparative Example 1, although the light-transmissive substrate 11 having ultraviolet absorption is interposed, the absorption is not 100%, and the width of the first colored portion 121 Since the width W1a and the width W2a of the second colored portion 131 are large enough to be visually recognized, mixed colors are visually recognized due to the influence of the reflected light from the opposite surface to the viewing surface.

In the observation of the anti-copying medium 1 and the copy 2 according to Comparative Example 2 under excitation light irradiation, color mixture derived from the arrangement of the first colored portion 121 and the second colored portion 131 was observed on the first surface and the second surface. In the observation, each image was visually recognized, and the difference in color between the anti-copying medium 1 and the copy 2 could not be distinguished with the naked eye.

As described above, in the observation of the anti-copying media 1 according to Examples 1 to 3 under excitation light irradiation, even in the observation from the first surface and the second surface, The image was viewed as a single color. On the other hand, in the copy 2, even when observed from the first side and the second side, the image is visually recognized as a mixture of colors derived from the arrangement of the first colored portions and the second colored portions. color difference could be distinguished.

DESCRIPTION OF SYMBOLS 1... Copy prevention medium, 2... Copies, 11... Light transmissive substrate, 12... First colored layer under white light, 13... Second colored layer under white light, 14... Print layer, 15... Excitation light Lower first colored layer 16 Second colored layer under excitation light 21 Light transmissive substrate 22 First colored layer 23 Second colored layer 121 First colored portion 122 Second 1 non-colored portion 131 second colored portion 132 second non-colored portion 221 dot-shaped portion 231 dot-shaped portion IL illumination light LS light source OB observer P1 pitch P2...pitch, R1A...first printing area, R1B...first non-printing area, R2A...second printing area, R2B...second non-printing area, REF...diffuse reflector, RL...reflected light, TL...transmitted light, W... window, W1a... width of the first colored portion, W1b... width of the first uncolored portion, W2a... width of the second colored portion, W2b... width of the second uncolored portion

Claims (9)

a light-transmissive substrate having a first surface and a second surface opposite to the first surface, wherein the light-transmissive substrate has ultraviolet absorption;
The first surface comprises a plurality of first colored portions and a plurality of first non-colored portions arranged alternately,
The second surface comprises a plurality of second colored portions and a plurality of second non-colored portions arranged alternately,
A copy preventing medium, wherein the width of the first non-colored portion and the second non-colored portion is in the range of 5 μm to 100 μm. The first colored portion reflects the first colored light, the second colored portion reflects the second colored light, and the first colored portion includes the first colored pigment and the first fluorescent pigment that is colored by the excitation light. wherein the second colored portion includes a second colored pigment having a color different from that of the first colored pigment and a second fluorescent pigment having a color different from that of the first fluorescent pigment 2. The anti-copy medium of claim 1, comprising a color layer. The second colored portion is arranged to face the first non-colored portion with the light-transmissive substrate interposed therebetween, and the second non-colored portion is arranged to face the first colored portion with the light-transmissive substrate interposed therebetween. 3. An anti-copying medium according to claim 1 or 2, characterized in that it is . The width of the first non-colored portion is smaller than the width of the second colored portion facing the first non-colored portion via the light-transmitting base material,
4. The anti-copying medium according to claim 3, wherein the width of said second non-colored portion is smaller than the width of said first colored portion facing said second non-colored portion with a light-transmitting base interposed therebetween. The first colored portion and the first uncolored portion have a linear shape and are arranged alternately in the width direction, and the second colored portion and the second uncolored portion have a linear shape and the width 4. The anti-copy medium of claim 3, arranged in alternating directions. 4. The copy preventing medium according to claim 3, wherein said first colored portion, said first non-colored portion, said second colored portion and said second non-colored portion have a linear shape. 4. A copy preventing medium according to claim 3, wherein said first colored portion, said first non-colored portion, said second colored portion and said second non-colored portion include portions having curvilinear shapes. 4. The copy preventing medium according to claim 3, wherein the first colored portions form a nested array pattern, and the second colored portions form a nested array pattern corresponding to the first colored portions. . 4. A copy preventing medium according to claim 3, wherein said first colored portion and said first non-colored portion are arranged in a checkered pattern, and said second colored portion and said second non-colored portion are arranged in a checkered pattern.

Images