JP2018072388A - Printed matter and method for determining authenticity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed matter with an information code having a counterfeit prevention function of determining the authenticity of the printed matter by an easy method, the information code being required to be inexpensive.SOLUTION: A printed matter 10 having a counterfeit prevention function sequentially includes a base material 3 as a printable supporting body, a print layer 2 having a pattern of an information code, and a counterfeit prevention layer 1 in this order. The counterfeit prevention layer reflects either or both of an anticlockwise-rotational circular polarization and a clockwise-rotational circular polarization with a specific wavelength. The counterfeit prevention layer may contain a pigment in a flake form made of a solidified cholesteric liquid crystal and a binder.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printed matter in which information codes such as one-dimensional and two-dimensional codes are provided with a forgery prevention function, and a method for determining the authenticity of the printed matter.

  Information codes such as one-dimensional and two-dimensional codes are attached to securities such as commodities, various certificates and cash vouchers, and contribute to the significant efficiency of their management operations by carrying their attribute information. Yes. It is also widely used for tracks and traces.

  Thus, although it is an information code frequently used in various directions, since it does not have a forgery prevention function, for example, fraudulent acts of forging securities are steadily increasing and tend to increase. Therefore, various anti-counterfeit technologies have been proposed.

  For example, Patent Document 1 provides a one-dimensional barcode that is difficult to counterfeit, so that the absorption characteristics of near-infrared light are different from each other, and both are read by a barcode reader that uses near-infrared light as a light source. A one-dimensional barcode capable of preventing forgery is disclosed, which is composed of two possible types of bars, and one of the bars is used for authenticity determination.

  In this technique, a bar code reader using near infrared light as a light source is required, and a person cannot make a true / false judgment visually.

  Patent Document 2 discloses authenticity using a polymer cholesteric liquid crystal in order to provide a security medium that is extremely difficult to counterfeit, has high distinguishability, and is inexpensive and can be applied to commonly distributed products. An identification structure for identifying is disclosed. This technique is a technique that makes it possible to identify reflected light from the identification structure by visually recognizing it through a polarizing filter.

  This technique is an excellent technique with high discrimination, but does not consider the information code copy prevention function such as one-dimensional and two-dimensional codes.

  Patent Document 3 discloses a cholesteric film having a selective reflection wavelength band at least in the visible light region in order to provide a sheet with a forgery prevention function that is highly difficult to counterfeit when recording authentication information using characteristics of cholesteric liquid crystal. Forgery prevention characterized by having a liquid crystal layer and a cholesteric liquid crystal layer having substantially the same thickness and having an authentication region having a selective reflection wavelength band different from that of other regions in at least one place A functional seat is disclosed. The authentication area has authentication information.

  This technology is an excellent technology that can give authentication information to the cholesteric liquid crystal layer, but as a process for producing the sheet with anti-counterfeit function, at least nematic liquid crystal, chiral agent and ultraviolet reaction A step of applying a polymerizable liquid crystal exhibiting cholesteric properties comprising an initiator, a step of irradiating UV light patterned based on authentication information to be recorded from one side of the coating surface, and the other side of the coating surface after this irradiation step The manufacturing process including the step of irradiating ultraviolet rays from the side is required. In addition, an authentication system for authenticating the sheet with a forgery prevention function is required. For this reason, it is considered difficult to manufacture a sheet with a forgery prevention function by this technique at a low price.

Patent Document 4 discloses that it is inexpensive to form a latent image such as a hidden character or pattern, which is difficult to forge with a commercially available color copying machine, etc., and whether the latent image is a genuine product or a counterfeit product using a simple device. In order to provide an anti-counterfeit ink that enables discrimination, an anti-counterfeit ink containing a flaky polarizing pigment (polymer cholesteric liquid crystal) having left and right polarizability, an anti-counterfeit printed matter, and a method for determining authenticity It is disclosed.

  The anti-counterfeit printed matter using the anti-counterfeit ink causes a color shift depending on the viewing angle, which is the same effect as an OVD (Optical Verifiable Device) image, and is difficult to counterfeit by a commercially available color copier, etc. This is an excellent technique that enables the formation of a latent image to be made inexpensively and allows the determination of whether the latent image is a genuine product or a counterfeit product with a simple device.

  For example, when printing information codes such as one-dimensional codes and two-dimensional codes using this anti-counterfeit ink, the anti-counterfeit ink containing flake-like polarizing pigments made of polymer cholesteric liquid crystal has sufficient color depending on the viewing angle. In order to cause the shift, a thickness of about 10 μm is required. However, when printing an information code, an ink layer of several μm or less is required to obtain a good pattern shape. For this reason, when an information code capable of observing a sufficient color shift is printed using this anti-counterfeit ink, it is considered that the information code is limited to an information code having a rough pattern.

JP-A-2-30489 Japanese Patent No. 36552476 JP 2006-142699 A Japanese Patent No. 4172199

  In view of the above circumstances, the present invention can be applied to a printed matter provided with an information code that is required to be inexpensive, and a printed matter having a forgery prevention function capable of determining its authenticity by a simple method. The issue is to provide.

As means for solving the above-mentioned problems, the invention according to claim 1 of the present invention includes a base material that is a printable support, a printing layer having an information code pattern, and a forgery prevention layer in this order. A printed matter having a forgery prevention function,
The anti-counterfeit layer is a printed matter characterized in that either a left-handed circularly polarized light, a right-handed circularly polarized light, or both of the circularly polarized light has a property of reflecting only a specific wavelength.

  The invention according to claim 2 is characterized in that the anti-counterfeit layer contains a flaky pigment made of solidified cholesteric liquid crystal and a binder, and the anti-counterfeit function according to claim 1 A printed matter characterized by comprising:

The invention described in claim 3 is a method for determining the authenticity of the printed matter having the anti-counterfeit function described in claim 1 or 2,
The anti-counterfeiting layer has a property of reflecting only one specific wavelength of either the left-handed circularly polarized light or the right-handed circularly polarized light, or both of the circularly-polarized light, and is disposed on the surface of the anti-counterfeit layer. Detecting by using a right-rotating circularly polarizing plate and a left-rotating circularly polarizing plate, or by detecting the reflected light from the printed material from directly above and obliquely from above, This is a sex determination method.

  According to the printed matter provided with the anti-counterfeit function of the present invention, it can be manufactured by adding a process of forming one anti-counterfeit layer to the manufacturing process of the printed matter provided with the conventional information code. It is possible to provide a printed matter having an anti-counterfeit function without significantly increasing the manufacturing cost of the printed matter.

  Further, according to the authenticity determination method of the present invention, a simple detector equipped with a circularly polarizing plate is used, or reflected light from a printed material having the anti-counterfeit function of the present invention is visually recognized from different angles. Thus, authenticity can be determined.

The schematic sectional drawing which shows an example of the information code provided with the forgery prevention function of this invention. The method of confirming the property of reflecting only a specific wavelength of either or both of the left-handed circularly polarized light and the right-handed circularly polarized light provided in the information code having the anti-counterfeit function of the present invention. Schematic explanatory drawing which shows an example. The method of confirming the property of reflecting only a specific wavelength of either or both of the left-handed circularly polarized light and the right-handed circularly polarized light provided in the information code having the anti-counterfeit function of the present invention. Schematic explanatory drawing which shows an example.

<Printed matter with anti-counterfeiting function>
The printed matter provided with the anti-counterfeit function of the present invention will be described with reference to FIG.
The printed matter 10 having the anti-counterfeit function of the present invention includes a substrate 3 that is a printable support, a print layer 2 having an information code pattern, and an anti-counterfeit layer 1 in this order.
The anti-counterfeit layer 1 is characterized in that it has a property of reflecting either a circularly polarized light of left rotation or a circular rotation of right rotation or both circular polarizations only at a specific wavelength.

  The anti-counterfeiting layer 1 is a solidified cholesteric as a means for expressing either the left-handed circularly polarized light, the right-handed circularly-polarized light, or both of the circularly-polarized light to reflect only a specific wavelength. A flake pigment made of liquid crystal and a binder may be included.

(Base material)
As the base material 3 that can be used for the printed material 10 having the anti-counterfeit function of the present invention, it is not necessary to limit the material. Any support can be used as long as it can form information codes represented by one-dimensional and two-dimensional codes using various inks. Various paper sheets, various resin sheets, and composite materials of paper and resin Or laminated materials can be used.

(Print layer)
The printing layer 2 is various ink layers composed of patterns representing information codes. The various ink layers may be formed by, for example, offset printing using normal offset printing ink, or may be a direct printing method. As the plate type, a suitable one such as a lithographic plate, an intaglio plate, and a relief plate may be adopted. Further, screen printing, ink jet printing, dry and wet electrophotography, and electrostatic printing may be used. There is no particular limitation as long as it is a pattern forming technique capable of forming a pattern representing an information code.

(Forgery prevention layer)
The anti-counterfeit layer 1 is a layer that has a property of reflecting only a specific wavelength of either one of the circularly polarized light rotated to the left and the circularly polarized light rotated to the right or both. The property of reflecting either a left-handed circularly polarized light, a right-handed circularly polarized light, or both circularly polarized lights only at a specific wavelength is that a substance with a chiral internal structure absorbs circularly polarized light. This refers to a phenomenon in which a difference in absorbance occurs between polarized light and right circularly polarized light.

Specifically, examples of the material exhibiting the property of reflecting only a specific wavelength of either or both of the left-handed circularly polarized light and the right-handed circularly polarized light include cholesteric polymer liquid crystal pigments. it can. A cholesteric polymer liquid crystal pigment is a pigment obtained by orienting a three-dimensional cross-linkable liquid crystal substance having a chiral phase, three-dimensionally cross-linking, and pulverizing to a desired particle size. The light reflected by this pigment is circularly polarized.
Among the above liquid crystalline substances, cholesteric liquid crystals have a twisted structure, and the refractive index of light periodically varies along the twist axis, so that light having a wavelength equal to the pitch is selectively reflected.
Therefore, it is possible to produce a desired cholesteric color by controlling the pitch. In addition, a liquid crystal having a twisted structure is formed by arranging each molecule in a layer, and the optical characteristics are formed only when the molecules are uniformly arranged in the layer. In this case, the molecules change their preferred directions from layer to layer, resulting in a twisted structure. The orientation of each molecule can be controlled by a known method such as an orientation layer or an electric field or a magnetic field. A typical method for immobilization is a combination of a three-dimensional cross-linkable liquid crystal substance having a chiral phase and a polyfunctional polymerizable compound, which can be three-dimensionally cross-linked by ultraviolet irradiation to immobilize a twisted structure. A polymer liquid crystal is produced.

As the starting material for the cholesteric polymer liquid crystal, all cholesteric liquid crystal materials having a twisted structure having a pitch equal to the wavelength of ultraviolet to infrared light are preferable. That is,
A liquid crystal material having a chiral phase can be produced by adding a chiral material to a nematic, smectic or discotic structure. The type and molecular weight of the chiral substance determine the pitch of the twisted structure, and hence the wavelength of the reflected light. The twist direction of the structure may be leftward or rightward. Furthermore, the starting material has a polymerizable group, a polycondensable group or a group effective for polyaddition, and among these groups, at least a part exhibits bifunctionality, trifunctionality and polyfunctionality, for example, It preferably has a methacryloxy group, an acryloxy group or the like, and a three-dimensional crosslinkable liquid crystal polyorganosiloxane is preferable.

  The method for producing the cholesteric polymer liquid crystal pigment is, for example, while heating a mixed solution of a three-dimensional crosslinkable liquid crystal polyorganosiloxane and a photopolymerization initiator on a metal support, a plastic support or a glass support. Application is performed while applying a shearing force using a doctor to align liquid crystal molecules. Next, the liquid crystal layer is irradiated with ultraviolet rays to be three-dimensionally crosslinked. The three-dimensionally crosslinked liquid crystal layer is peeled off from the support and pulverized with a universal mill or the like to obtain a flake pigment. The pigment has a particle size of 5 μm to 5 mm and a thickness of 1 to 100 μm, preferably 5 to 50 μm. The support may optionally have an alignment layer made of, for example, polyimide or polyvinyl alcohol. Further, the liquid crystal molecule alignment method can be sheared between two sheets, and preferably includes a method using polyethylene terephthalate.

  The anti-counterfeit ink can be used as an ink for printing methods such as gravure printing and screen printing depending on the types of the binder (binder), dispersant and auxiliary agent. The anti-counterfeit ink preferably contains, for example, 10 to 50% by weight of the cholesteric polymer liquid crystal pigment.

<Authenticity judgment method>
Next, a method for determining the authenticity of a printed matter having a forgery prevention function according to the present invention will be described with reference to FIGS.

  The method of determining the authenticity of the printed material 10 having the anti-counterfeit function according to the present invention specifies either the left-handed circularly polarized light or the right-handed circularly-polarized light, or both of the circularly-polarized light provided in the anti-counterfeit layer. The property of reflecting only the wavelength of the anti-counterfeit layer is detected using a right-rotating circularly polarizing plate and a left-rotating circularly polarizing plate disposed on the surface of the anti-counterfeit layer, or the reflected light from the printed material is detected by the true color of the printed material. Detection is performed by visual inspection from above and obliquely from above.

  FIG. 2 shows a case where the printed material 10 having the anti-counterfeit function is viewed from a position A (vertical direction) observed from directly above the surface of the printed material 10 having the anti-counterfeit function according to the present invention, and an obliquely upper direction. In the case of the position B to be observed, in the printed matter 10 having the anti-counterfeit function of the present invention, the color of the printed matter 10 provided with the anti-counterfeit function when viewed from A, and visible from B In this case, the color of the printed matter 10 having a forgery prevention function is different. When the anti-counterfeit layer is not formed, the present invention does not exhibit a property of reflecting only one specific wavelength of either the left-handed circularly polarized light, the right-handed circularly polarized light, or both of the circularly polarized light. It is possible to determine the authenticity of the printed matter 10 having the anti-counterfeit function.

FIG. 3 shows a method of confirming the property of reflecting only a specific wavelength of either or both of the left-handed circularly polarized light and the right-handed circularly polarized light. The example using the circularly-polarizing plate 5 is shown.
The right-handed circularly polarizing plate 4 and the left-handed circularly polarizing plate 5 according to the present invention include a PVA-iodine type, a dichroic dye type, a metal or metal compound-containing type, a polyene, and the like. A polymer polycrystal type, such as a mold, is conceivable, in particular a polarizing film using a PVA-iodine type, dichroic dye type film and a 1 / 4λ wavelength phase difference film superimposed, and the phase difference is 1 / The direction of right or left rotation is determined by advancing or delaying by 4λ.

  Therefore, natural light becomes right-handed polarized light by passing through the right-handed circularly polarizing plate 4, but has entered since the cholesteric polymer liquid crystal having a right-handed twisted structure is contained in the polarizing layer. Of the right-handed polarized light, only the right-handed polarized light having a wavelength equal to the twist pitch is reflected on the surface of the polarizing layer, and the observer can visually recognize the reflected light. On the other hand, the counterclockwise polarized light that has passed through the counterclockwise circularly polarizing plate 5 includes cholesteric polymer liquid crystal having a left-handed twisted structure in the polarizing layer. Only the counterclockwise polarized light having a wavelength equal to the twist pitch is reflected by the surface of the polarizing layer, and the observer can visually recognize the reflected light. Using this fact, if this phenomenon occurs, it can be determined as a genuine product, and if it does not occur, it can be determined as a counterfeit product.

  In addition, since the same effect is acquired also by the structure which printed the printing cholesteric liquid crystal pigment on the printing layer, it can be used for determination of authenticity.

  Next, examples of the present invention will be described.

<Example 1>
As a base material, A4 size label paper (manufactured by Oji Tuck Co., Ltd.) with an adhesive layer and a separator was prepared. A two-dimensional code made of toner (black) was printed on the label paper using a laser printer.

  After printing the two-dimensional code on the label paper, the two-dimensional code was formed by screen printing security ink for screen printing (OASIS (registered trademark of SICPA), Red / Green (R + L) SILKSCREEN 5ZB, manufactured by SICPA). I printed it all on the label paper on the side. The screen plate used was T200SB.

The printed security ink is dried with a 1.5 kW standard conveyor type UV dryer using an ultra-high pressure mercury lamp under the conditions of an integrated light quantity of 254 mJ / cm ² and a peak power of 462 mW / cm ^{2 to} prevent counterfeiting. A printed matter that is a two-dimensional code with functions was created.

  The result of reading the two-dimensional code on the label paper created in this way with a smartphone installed with a two-dimensional code reading application (QR code (registered trademark), registered trademark of Denso Wave) Reader “Q” It was possible to read well before and after printing the security ink.

Next, it was visually confirmed that the color of the two-dimensional code changes from red to green by changing the observation angle (the two-dimensional code on the label sheet is directly above and obliquely upward).
In addition, it was confirmed that a simple verifier using a circularly polarizing filter was changed to red and green by holding it over a two-dimensional code having a forgery prevention function.

DESCRIPTION OF SYMBOLS 1 ... Anti-counterfeiting layer 2 ... Printing layer 3 ... Base material 4 ... Right-rotating circularly-polarizing plate 5 ... Left-rotating circularly-polarizing plate 10 ... Information with anti-counterfeiting function Code A: Position observed from directly above B: Position observed from diagonally above

Claims (3)

A printed matter having a forgery prevention function comprising a base material that is a printable support, a printing layer having an information code pattern, and a forgery prevention layer in this order,
The anti-counterfeiting layer has a property of reflecting only a specific wavelength of either or both of left-handed circularly polarized light and right-handed circularly polarized light, or both of them.   2. The printed matter having the anti-counterfeit function according to claim 1, wherein the anti-counterfeit layer contains a flake pigment made of solidified cholesteric liquid crystal and a binder. A method for determining the authenticity of the printed matter having the forgery prevention function according to claim 1,
The anti-counterfeiting layer has a property of reflecting only one specific wavelength of either the left-handed circularly polarized light or the right-handed circularly polarized light, or both of the circularly-polarized light, and is disposed on the surface of the anti-counterfeit layer. Detecting by using a right-rotating circularly polarizing plate and a left-rotating circularly polarizing plate, or by detecting the reflected light from the printed material from directly above and obliquely from above, Gender determination method.

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