JP4669545B2 - Authenticity discriminator, authenticity discrimination method, and authenticity discriminator manufacturing method - Google Patents

Description

The present invention relates to an authenticity identifying object, an authenticity identifying method, and an authenticity for easily determining authenticity of an object such as a card, gift certificate, cash voucher, ticket, banknote, passport, identification card, securities, public competition voting ticket, etc. Method for producing sex identifier

Conventionally, as a method for preventing counterfeiting of credit cards, certificates, and vouchers, there is known a method of attaching authenticity identification media difficult to counterfeit to an anti-counterfeit object and judging the authenticity visually or mechanically. It has been. Such authentic identification media include those using holograms, liquid crystal films, stretched films, and the like.
Examples of applying the hologram include visual discrimination using characters and pictures as hologram images, machine recognition using numerical codes and specific patterns as hologram images, and combinations of both. Hologram images have become widespread because they cannot be duplicated by a normal color copying apparatus or the like, are effective in preventing forgery, have high designability, and are difficult to manufacture.
As a liquid crystal film, a method using a cholesteric liquid crystal whose reflection color changes depending on a viewing angle (Japanese Patent Laid-Open No. 63-51193), a method using a nematic liquid crystal having optical anisotropy, etc. (Kaihei 8-43804) is proposed.
As an application of a stretched film, a method of determining whether a hidden mark is visible by forming a hidden mark on the stretched film and visually recognizing it with a discriminator (Japanese Patent Laid-Open No. 9-68926). ) Etc. have been proposed.

However, the application of the above-described conventional hologram has made it possible to manufacture counterfeit products with the recent spread of hologram manufacturing technology, and the effect of preventing forgery has been reduced.
In addition, the liquid crystal film applied is difficult to counterfeit the liquid crystal film, but it is also difficult for the practitioner to mass-produce it.
Furthermore, the one using the stretched film requires a discriminator, and cannot authenticate if there is no discriminator. Moreover, since it judges visually, there exists a possibility of misidentification.

An object of the present invention is to provide an authenticity discriminator, an authenticity discriminating method, and an authenticity discriminating method capable of easily performing authenticity discrimination visually.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.

According to the first aspect of the present invention, the base material (11), the reflective layer (12) formed on the base material (11) and reflecting light, and the light transmitted through the reflective layer (12) are transmitted by birefringence. , A birefringent layer (13) that gives a phase difference and makes light of a predetermined polarization direction, and is formed in the birefringent layer (13), transmits light of a different polarization direction depending on the region (14a), and transmits the region (14a And a polarizing layer (14) that forms identification information according to the shape of ().

The invention of claim 2 is the authenticity discrimination of claim 1, between the reflective layer (12) birefringent layer (13), and further comprising a hologram layer or a diffraction grating layer It is an authenticity identifier.

According to a third aspect of the present invention, there is provided the authenticity identifying object according to the first or second aspect , wherein the authenticity identifying object is formed in a card shape.

According to a fourth aspect of the present invention, there is provided the authenticity identifying object according to the first or second aspect , further comprising an adhesive layer (15) capable of adhering to an adherend, and formed into a label shape. It is an identifier.

The invention of claim 5 is an authenticity identification method using the authenticity identifier according to any one of claims 1 to 4 , wherein the color is changed by changing the viewing angle. The authenticity identifying method is characterized by identifying authenticity by:

The invention according to claim 6 is the method for producing the authenticity identifier according to claim 2, wherein the polarizing layer is formed by applying a dichroic dye to the alignment film, and a part of the alignment film is formed. By rubbing the region in a certain direction and changing the orientation direction of the region from other regions, the polarization direction of light that can be transmitted through the region is changed, and identification information is formed. It is a manufacturing method of the authenticity identification body characterized.

The invention according to claim 7 is the method for producing an authenticity identifier according to claim 2, wherein the polarizing layer is formed by applying a dichroic dye to an alignment film, and the alignment film is entirely formed. After the rubbing process is performed in a certain direction, the rubbing process is performed on a part of the region in a different direction to change the orientation direction from that of the other regions. This is a method for producing an authenticity identifier, characterized in that identification information is formed.

The invention according to claim 8 is the method for producing an authenticator according to claim 2, wherein the polarizing layer uses a photoactive material as an alignment film, and the alignment film is irradiated with linearly polarized light. And a method of manufacturing an authenticity identifier, wherein the orientation information of the orientation film is controlled to form identification information.

  As described above in detail, according to the present invention, the following effects can be obtained.

  According to the present invention, when the light transmitted through the polarizing layer is viewed under natural light, the authenticity is identified depending on whether the color changes according to the viewing angle. Can do.

  According to the present invention, when the reflected light is viewed under natural light, the authenticity is identified depending on whether or not the color changes according to the viewing angle. High designability.

  According to the present invention, since the reflective layer for displaying the identification information is provided, it is possible to easily authenticate and to improve the design.

  According to the present invention, since the birefringent layer having the identification information is provided, the authentic identification can be easily performed and the design property is high.

  According to the present invention, since the polarizing layer having the identification information is provided, it is possible to easily authenticate and to improve the design.

  According to the present invention, since a hologram layer or a diffraction grating layer is further provided between the reflective layer and the birefringent layer, a higher security effect and design can be obtained.

  According to the present invention, since it is in the form of a card, it is possible to provide a card that is convenient to carry and difficult to counterfeit / modify.

  According to the present invention, since the adhesive layer is provided, it is possible to provide a label that can be attached to an adherend and is difficult to forge or alter.

  According to the present invention, since the authenticity is identified depending on whether the color is changed by changing the viewing angle, the authenticity can be easily identified.

  According to the present invention, since the reflective layer is formed in the shape of the identification information by irradiating the laser beam, it is possible to add information and improve the design. Also, it is suitable for small-scale production, and security can be further improved if each identifier has different information.

  According to the present invention, since the identification information is formed on the birefringent layer by irradiating the laser beam, it is possible to add information and improve the design. Also, it is suitable for small-scale production, and security can be further improved if each identifier has different information.

  According to the present invention, since the identification information is formed on the birefringent layer by irradiating with ultraviolet rays, it is possible to add information and improve the design. Also, it is suitable for small-scale production, and security can be further improved if each identifier has different information.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a first embodiment of an authenticity identifier used in an authenticity identification method according to the present invention. In the figure, (A) is a plan view, and (B) is a cross-sectional view taken along the line BB of (A).
The authenticator 10 includes a base material 11, a reflective layer 12, a birefringent layer 13, and a polarizing layer 14. The authenticity identification body 10 is formed in a card shape.

  The substrate 11 is a substrate that serves as a carrier for the authenticity identifier. The substrate 11 is made of a plastic film (for example, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl alcohol (PVAL), polyvinyl chloride (PVC), polycarbonate, which is generally used as the material. (PC), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene copolymer (AS), polymethyl methacrylate (PMMA), cellulose acetate butyrate (CAB), cellulose propionate (CP), etc. Etc.) can be suitably used. Further, it may be a base material (for example, high-quality paper, art paper, coated paper, synthetic paper, or other paper) that is inferior in smoothness compared to a plastic film.

The reflective layer 12 is a layer that reflects incident light, and is formed on the substrate 11. The reflective layer 12 is formed by forming a metal thin film by depositing or sputtering a metal such as aluminum, tin, or gold. The reflective layer 12 may be formed by coating or printing a coating type ink containing a metal such as aluminum. In general, a coating film formed from coating-type ink is inferior in smoothness (specularity) as compared with a vapor deposition film, but in the present invention, it is not necessary to be a mirror surface, and it is sufficient if the reflected light can be detected visually or with a detector. Because.
The thickness of the reflective layer 12 is not particularly limited, but is desirably about 500 mm or more in order to sufficiently perform the function of reflecting light.

The birefringent layer 13 is a layer that birefringes incident light, and is formed on the reflective layer 12. Birefringence is a phenomenon that occurs because the refractive index of a medium is not uniform depending on the polarization direction, and the phase difference σ of light transmitted through such a medium is
_{σ = 2π (n e -n o} ) d / λ
n _e : ordinary ray refractive index
n _o : extraordinary ray refractive index
d: thickness of the medium
λ: It is known to be given by the wavelength of light. That is, the phase difference σ depends on the wavelength λ of light as well as the thickness d.
The birefringent layer 13 causes a color change together with the polarizing layer 14 as described later.

The birefringent layer 13 can be formed of a plastic film produced by a stretching process. Stretching is a method for producing a film by stretching a plastic at an appropriate temperature not higher than the melting point and not lower than the glass transition point, and includes uniaxial stretching and biaxial stretching depending on the stretching direction. In the present invention, since it is sufficient that the refractive index anisotropy exists, a film produced by any one of the uniaxial stretching method and the biaxial stretching method can be used.
Specifically, the birefringent layer 13 is made of cellophane, polyester, polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVAL), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polystyrene (PS), It can be formed using a stretched film made of polyethylene terephthalate (PET), polycarbonate (PC), nylon or the like.

  The birefringent layer 13 is formed by adhering to the reflective layer 12. For this bonding, thermosetting resins (for example, phenol resins, furan resins, urea resins, melamine resins, polyester resins, polyurethane resins, epoxy resins and other resins), thermosetting resins (for example, , Polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride resin, polyvinyl butyral resin, poly (meth) acrylic resin, nitrocellulose, polyamide and other resins), rubber (for example, butadiene-acrylonitrile rubber, neoprene rubber and other rubber), Nikawa Adhesives composed mainly of one or more of natural resin, casein, sodium silicate, dextrin, starch, gum arabic and the like can be used. These adhesives may be any of a solution type, an emulsion type, a powder type, or a film type. Furthermore, these adhesives may be any of a room temperature solidification type, a solvent volatile solidification type, or a melt solidification type.

  The polarizing layer 14 is a layer that transmits only light in a specific polarization direction, and is formed in the birefringent layer 13. The polarizing layer 14 can be formed of a polarizing film or sheet in which a stretched film such as polyvinyl alcohol (PVAL) has absorbed a dye such as a dichroic dye. The polarizing layer 14 is formed by adhering such a polarizing film sheet to the birefringent layer 13. For this adhesion, the same adhesive as the adhesive for adhering the birefringent layer 13 to the reflective layer 12 described above can be used.

FIG. 2 is a schematic diagram for explaining the reason why the authenticity identifier appears to be colored.
(1) Of the light 21 of the white light source 20, only the linearly polarized light 22 that matches the polarization direction of the polarizing layer 14 is transmitted through the polarizing layer 14.
(2) (1), the linearly polarized light 22 that has passed through the polarization layer 14, for each wavelength lambda in the birefringent layer 13, a different phase difference _{σ (= 2π (n e -n} o) d / λ) elliptically polarized light 23.
(3) In (2), the converted elliptically polarized light 23 is reflected by the reflective layer 12 and becomes reflected light 24.

(4) In (3), reflected reflected light 24, for each wavelength lambda in the birefringent layer 13, a different phase difference _{σ (= 2π (n e -n} o) d / λ) are given, elliptically polarized light 25 Is converted to
(5) In (4), only the linearly polarized light component 26 that matches the polarization direction of the polarizing layer 14 among the converted elliptically polarized light 25 is transmitted through the polarizing layer 14.
(6) Since the polarization state of the elliptically polarized light 25 is different for each wavelength, the amount of light transmitted through the polarizing layer 14 in (5) is different for each wavelength. Therefore, even if the incident light 21 is white light, the reflected light 26 from the discriminating body appears to be colored in a color corresponding to the intensity distribution because the wavelength intensity distribution is different.

FIG. 3 is a schematic diagram for explaining the reason why the authenticity identifier changes color depending on the viewing angle.
The light emitted from the light source 20a is transmitted through the polarizing layer 14 and the birefringent layer 13, reflected by the reflective layer 12, and again transmitted through the birefringent layer 13 and the polarizing layer 14.
On the other hand, the light emitted from the light source 20b is similarly transmitted through the polarizing layer 14 and the birefringent layer 13, reflected by the reflective layer 12, and again transmitted through the birefringent layer 13 and the polarizing layer 14.
At this time, the light emitted from the light source 20a and the light emitted from the light source 20b are different in distance transmitted through the birefringent layer 13, so that the wavelength intensity distribution of the light transmitted through the polarizing layer 14 is also different and different colors. Looks like.

(Authenticity identification method)
The discriminator authentically identifies the authenticator 10 using the following method.
(1) The classifier visually checks the authenticity classifier 10 and confirms the color.
(2) In (1), the classifier who confirmed the color tilts the authenticity classifier 10.
At this time, the discriminator can identify the authentic identifier 10 as a genuine product when the color changes, and can identify the counterfeit product when the color does not change.

According to the present embodiment, since the authenticity identification body 10 changes in color depending on the viewing angle, the authenticity identification can be easily performed.
That is, it can be seen that a counterfeit product such as a color copy is a counterfeit product because the color does not change.
Further, since the authenticity identification body 10 changes in color depending on the viewing angle, it is rich in design.
Furthermore, since the birefringent layer 13 can be formed of a plastic film, it can be mass-produced at low cost.

(Second Embodiment)
FIG. 4 is a diagram showing a second embodiment of the authenticity identifier used in the authenticity identification method according to the present invention. In the figure, (A) is a plan view, and (B) is an BB enlarged cross-sectional view of (A). FIG. 5 is a schematic diagram showing how to use the second embodiment of the authenticity identifier according to the present invention.
In each embodiment described below, parts having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted as appropriate.
The authenticity identification body 10 includes a base material 11, a reflective layer 12, a birefringent layer 13, and an adhesive layer 15. The authenticity identification body 10 is formed in a label shape.
The authenticity identification body 10 of the present embodiment does not include the polarizing layer 14 but differs from the first embodiment in that it includes the adhesive layer 15.
The authenticator 10 is affixed to the gift certificate 30.

(First authenticity identification method)
The discriminator authentically identifies the authenticator 10 using the following method.
(1) The discriminator irradiates the authenticator 10 with laser light 22 that is linearly polarized light having a single wavelength.
At this time, the wavelength of light is
_{λ = 4 (n e -n o} ) d
It is. The birefringent layer 13 functions as a so-called λ / 4 plate that emits light having a phase difference σ = π / 2 when such light is incident.
That is, the birefringent layer 13 functions as a λ / 4 plate, converts the incident linearly polarized light 22 into the circularly polarized light 23 and emits it, enters the reflected circularly polarized light 24, and converts it into the linearly polarized light 25. Eject.
At this time, the polarization direction of the linearly polarized light 25 is rotated by 90 degrees with respect to the polarization direction of the linearly polarized light 22.

In (2), the classifier who irradiates the authenticator 10 with the laser beam 22 detects the polarization direction of the reflected light 25 reflected by the authenticator 10 with a detector.
At this time, the discriminator can identify the genuine product when the polarization direction of the reflected light 25 is 90 degrees different from the polarization direction of the irradiated laser beam 22.

(Second authenticity identification method)
The discriminator authentically identifies the authenticator 10 using the following method.
(1) The classifier visually checks the authenticity classifier 10 and confirms the color. At this time, the birefringent layer 13 looks colorless and transparent.
(2) In (1), the discriminator who has confirmed the authenticity identifier 10 applies a discriminator using the polarizing film 14 to the authenticity identifier 10 and confirms the color of the birefringent layer 13. The polarizing film 14 has the same structure as the polarizing layer described above, and is formed of a polarizing film or sheet in which a stretched film such as polyvinyl alcohol (PVAL) absorbs a dye such as a dichroic dye. .
At this time, the birefringent layer 13 appears to be colored.
(3) In (2), the discriminator who applied the discriminator and confirmed the color looks at the authenticity discriminator 10 while tilting the discriminator.
At this time, the discriminator can identify the genuine product when the color of the birefringent layer 13 changes, and can identify the product as a counterfeit when the color does not change.

According to this embodiment, a genuine product can be easily identified by irradiating a predetermined single wavelength light and detecting the reflected light. Even if counterfeiting is attempted, the thickness of the birefringent layer 13 cannot be matched with the genuine product. Therefore, it can be reliably identified that the direction of polarization of the reflected light is different from the genuine product and is a counterfeit product.
Further, since the birefringent layer 13 changes its color when the viewing angle is changed by applying a discriminator by the polarizing film 14, authenticity can be easily identified.
Furthermore, since the birefringent layer 13 usually appears colorless and transparent, a third party does not realize that it is an authenticity identifier.

(Third embodiment)
FIG. 6 is a diagram showing a third embodiment of the authenticity identifier according to the present invention. In the figure, (A) is a plan view, and (B) is a cross-sectional view taken along the line BB of (A).
The reflective layer 12 of the authenticity identification body 10 is formed in a shape such as a character or a pattern in order to have design properties or information properties.
As a method for providing the reflective layer 12 with designability or information property, there is a method of irradiating a uniformly formed reflective layer with laser light to destroy the reflective layer and patterning.
In this case, first, the reflective layer 12 made of an aluminum vapor deposition film is uniformly formed on the base material 11 with a thickness of about 500 to 1000 mm, and then irradiated with YAG laser light of about 50 W, so that one of the reflective layers 12 is formed. The part is destroyed and formed.
Thus, the reflective layer 12 can be patterned into a character and a pattern by scanning the laser beam in a character and a pattern.
Patterning with a laser beam can be performed after the reflective layer is formed, before the birefringent layer is laminated, after the birefringent layer is laminated, or even after the polarizing layer is laminated thereon.

Many of the films such as polyester and polypropylene mentioned as examples of the birefringent layer do not absorb light in the visible light region and have little absorption in the near infrared region. Therefore, YAG laser light (wavelength 1064 nm) can pass through these birefringent layers. That is, only a reflective layer can be patterned by irradiating a laser beam after laminating a birefringent layer on the reflective layer.
Further, since the polarizing layer absorbs only a specific linearly polarized light component, all laser light such as linearly polarized light or circularly polarized light in the same direction can be transmitted without being absorbed. Therefore, by using a linearly polarized laser beam in the same direction as the orientation direction of the polarizing layer or a multimode laser beam containing a random polarization component, the reflective layer is patterned after the polarizing layer is stacked. You can also.
As described above, by performing patterning after laminating each layer, for example, individual information such as ID information and barcode can be given as the final stage after individually manufactured as a product form such as a card or label. .

As another method for providing the reflective layer 12 with design or information, (1) a mask patterned during the vapor deposition step is provided on the substrate 11 and the vapor deposition layer is formed into a mask pattern. (2) Method of forming a deposition layer in a pattern by forming a reflective layer 12 uniformly on the substrate 11 and then etching into a pattern using a photoresist or the like (3) There is a method of forming a pattern-like reflective layer by printing characters, pictures, etc. on the substrate 11 with ink having a reflective function.

According to the present embodiment, since it is possible to confirm the patterned characters, patterns, and the like at the time of authenticity identification, it is possible to easily identify authenticity.
In addition, since patterning is performed with laser light, different information can be given to each identification body, so that security can be further improved.

(Fourth embodiment)
FIG. 7 is a cross-sectional view showing a fourth embodiment of the authenticity identifier according to the present invention.
The birefringent layer 13 of the authenticity identification body 10 is patterned with characters, patterns, and the like in order to have design properties or information properties.
As a method of patterning the design property or information property of the birefringent layer 13, there is a method of irradiating a laser beam or an ultraviolet ray.
When the birefringent layer 13 is irradiated with laser light, the irradiated portion 13a is heated and rapidly cooled to change the crystal state. As a result, there is a difference in refractive index between the irradiated portion and the unirradiated portion, and patterning can be performed as a difference in color due to the above-described effect.
Further, when the birefringent layer 13 is irradiated with ultraviolet rays, the alignment state of the portion 13a changes, and the patterning can be performed in the same manner.

  Also according to the present embodiment, since it is possible to confirm a patterned character, pattern, or the like at the time of authenticity identification, it is possible to easily identify authenticity.

(Fifth embodiment)
FIG. 8 is a cross-sectional view showing a fifth embodiment of the authenticity identifier according to the present invention.
The polarizing layer 14 of the authenticity identification body 10 is patterned with characters, designs, etc. in order to have design properties or information properties.
As a method of patterning design properties or information properties on the polarizing layer 14, there is a method of forming a polarizing layer by applying a dichroic dye on an alignment film.
The orientation of the dichroic dye is determined by the alignment direction of the alignment film, and the direction of the linearly polarized light that is transmitted is determined by the direction of the dye. Therefore, the polarizing layer 14 can be patterned by changing the alignment direction of the alignment film into letters and patterns.
As a patterning method in the orientation direction, there are a method of performing a rubbing process partially, a method of performing a rubbing process in a partially different direction after performing a uniform rubbing process on the entire surface, and the like. There is also a method of controlling the alignment film by using a photoactive material for the alignment film and irradiating the alignment film with linearly polarized light.

  Also according to the present embodiment, since it is possible to confirm a patterned character, pattern, or the like at the time of authenticity identification, it is possible to easily identify authenticity.

(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
For example, the reflective layer 12, the birefringent layer 13, and the polarizing layer 14 may be formed only in necessary regions with respect to the base material 11.
In this case, if the decorative picture is given to the other part of the base material 11 and the base material 11 is a card base material, it can be the same as the gift certificate of the second embodiment.

In the second embodiment, the laser beam is irradiated. However, the same effect can be obtained by irradiating light transmitted through a polarizing layer such as a polarizing film. In this way, a light irradiation device can be easily made.
Furthermore, in the second embodiment, the polarization direction of the reflected light is detected by the detector. However, the polarization layer that transmits only the light having the predetermined polarization direction is used, and the reflection depends on whether or not the polarization layer is transmitted. The polarization direction of light may be detected. In this way, a light detection device can be easily made.

  Furthermore, in order to further enhance the design of the present technology, it can be combined with a hologram. That is, by providing a layer in which a hologram or a diffraction grating is formed between the reflective layer 12 and the birefringent layer 13, in addition to the color variable effect described above, a pattern image by a hologram image or a diffraction grating is combined, Higher security effects and design properties can be obtained. The hologram or diffraction grating may be either a relief type or a volume type.

  Further, as shown in FIG. 9, the authenticity may be identified by measuring the polarization state of elliptically polarized light 23 converted by birefringence in the birefringent layer 13. In this case, since it is not necessary to provide the reflective layer 12 on the authenticity identifier 10, the authenticity identifier 10 can be manufactured at low cost.

It is a figure which shows 1st Embodiment of the authenticity identification body used for the authenticity identification method by this invention. It is a schematic diagram explaining the reason for the authenticity identifier to appear colored. It is a schematic diagram explaining the reason for a color change with the angle which an authenticity identification body sees. It is a figure which shows 2nd Embodiment of the authenticity identification body used for the authenticity identification method by this invention. It is a schematic diagram which shows the usage method of 2nd Embodiment of the authenticity identification body by this invention. It is a figure which shows 3rd Embodiment of the authenticity identification body by this invention. It is sectional drawing which shows 4th Embodiment of the authenticity identification body by this invention. It is sectional drawing which shows 5th Embodiment of the authenticity identification body by this invention. It is a schematic diagram which shows the authenticity identification method by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Authentic identifier 11 Base material 12 Reflective layer 13 Birefringent layer 14 Polarizing layer 20, 20a, 20b Light source 30 Card

Claims (8)

A substrate;
A reflective layer that is formed on the substrate and reflects light;
A birefringent layer that is formed in the reflective layer and birefringently gives a phase difference by birefringence to make light of a predetermined polarization direction;
A genuine discriminator comprising: a polarizing layer formed on the birefringent layer, which transmits light having a different polarization direction depending on the region, and forms identification information according to the shape of the region. The authenticity identifier of claim 1 ,
An authenticity identifier, further comprising a hologram layer or a diffraction grating layer between the reflective layer and the birefringent layer. In the authenticity identifier according to claim 1 or 2 ,
An authenticity identifier formed in a card shape. In the authenticity identifier according to claim 1 or 2 ,
An authenticity identifier, further comprising an adhesive layer capable of adhering to an adherend, wherein the authenticity identifier is formed in a label shape. An authenticity identification method using the authenticity identifier according to any one of claims 1 to 4 ,
An authenticity identification method characterized by identifying authenticity according to whether the color changes by changing the viewing angle. A method for producing an authenticity identifier according to claim 2,
The polarizing layer is formed by applying a dichroic dye to the alignment film,
By rubbing in a certain direction to a part of the alignment film and changing the alignment direction of the region from other regions, the polarization direction of light that can be transmitted through the region is changed, Form identification information
A method of manufacturing an authenticity identifier. A method for producing an authenticity identifier according to claim 2,
The polarizing layer is formed by applying a dichroic dye to the alignment film,
The rubbing process is performed in a certain direction with respect to the entire alignment film, and then the rubbing process is performed in a different direction in a part of the region to change the orientation direction from the other region, thereby changing the region. Change the polarization direction of light that can be transmitted to form identification information
A method of manufacturing an authenticity identifier. A method for producing an authenticity identifier according to claim 2,
The polarizing layer uses a photoactive material as an alignment film,
The alignment film is irradiated with linearly polarized light to control the alignment direction of the alignment film and form identification information.
A method of manufacturing an authenticity identifier.

Images