JP5157057B2 - Color information intrinsic sheet, verification tool, and color information verification method - Google Patents

Description

The present invention, by observing through a predetermined validation tool, a lust paper endogenous sheet color change information that is internalized is able to validate, verification device for verifying the color change information as well as their on verification method of lust paper used.

  Conventionally, for authentication media such as cards and passports, securities such as gift certificates and stock certificates, etc., devices or information that are difficult to counterfeit are attached or printed on some of them, and the presence or contents of them are visually observed. Alternatively, the authenticity is determined by checking using a verifier.

  In recent years, the distribution of counterfeit products has become a problem, and in order to prevent such distribution, the application of technology equivalent to the anti-counterfeiting technology used in securities and the like is increasing for genuine products.

  Anti-counterfeiting technology can be recognized as a technology related to anti-counterfeiting by general users, and so-called overt technology that allows each user to judge authenticity, and only specific users can recognize it as technology related to anti-counterfeiting. The so-called covert technique is such that only a specific user can make a true / false judgment.

  Typical examples of the overt technique include a diffractive structure forming body such as a hologram, and a multilayer interference film such as Optically Variable Ink (abbreviated as OVI). Further, representative examples of the covert technique include fluorescent printing and line latent images. Both of these occupy important positions and are usually often adopted as anti-counterfeiting technology by combining them.

Further, with the recent increase in demand for liquid crystal displays, various advanced polarization technologies have been developed, and these polarization technologies are beginning to be applied in various forms as anti-counterfeit devices as covert technologies. For example, when a latent image medium using birefringence of a nematic liquid crystal or a plastic film having birefringence is physically stimulated and partially birefringent, and observed through a polarizing element. For example, a technique (for example, refer to Patent Document 1) that enables intended information to be read.
JP-A-8-43804 JP-A-9-68926 JP-A-9-68927 JP 2000-221898 A

  However, in these conventional methods, the orientation direction of the liquid crystal is partially changed in order to pattern the latent image (for example, see Patent Documents 2 and 3), or the film thickness of the stretched film is partially changed by embossing. (For example, refer to Patent Document 4), and it is necessary to destroy the birefringence by physical stimulation, and it is difficult to mass-produce a stable medium.

The present invention has been made in view of the above situation, and the inherent color change information cannot be confirmed in a normal state, but the inherent information can be verified only by observing through a predetermined verification tool. aims were, in particular which can be suitably used as a device for anti-counterfeit measures, the provision of verification tools and lust paper verification methods using them for verifying the lust paper endogenous sheet and its lust paper in It is.

Been made to solve the above problems, the invention according to claim 1, together have a birefringent transparent layer, the metal reflective layer is provided in at least some areas of its back side, a plurality And a birefringent transparent layer, and a metal reflective layer is provided in a partial region of an interlayer portion of the plurality of birefringent transparent layers. .

The invention according to claim 2 is that, in the color information-containing sheet according to claim 1, a metal reflective layer is provided in a partial region on the surface side of the plurality of birefringent transparent layers. Features.

Furthermore, the invention described in claim 3 is characterized in that, in the color information- containing sheet according to claim 1, the birefringent transparent layer is made of a stretched resin film.

Furthermore, the invention described in claim 4 is the color information-containing sheet according to any one of claims 1 to 3 , wherein the birefringent transparent layer is formed of a uniaxially stretched resin film.

Furthermore, the invention described in claim 5 is the color information-containing sheet according to any one of claims 1 to 4 , wherein the birefringent transparent layer is made of a cellophane film.

Furthermore, the invention described in claim 6 is characterized in that in the color information-containing sheet according to any one of claims 1 to 4 , the birefringent transparent layer is made of a polycarbonate film.

Furthermore, the invention described in claim 7 is the sheet-shaped lamination members for verifying the color change information of the color information inherent sheet according to any one of claim 1 to 6 into a linear polarizer At least the birefringent transparent layer is laminated, and the angle between the optical axis of the linearly polarizing plate and the optical axis of the birefringent transparent layer is set so as not to be 0 ° or 90 °. It is a featured verification tool.

Furthermore, in the invention described in claim 8 , the color information-containing sheet according to any one of claims 1 to 6 is superposed on the linearly polarizing plate or the verification tool according to claim 7 , and the color information-containing sheet is overlapped. In this color change information verification method, the hue of the color change information contained therein is changed to a visible state so that the information content is verified visually.

According to the present invention, by simply observing by superimposing predetermined verification tool, as in a normal state can be verified clearly and simply and inherent information in lust paper endogenous sheet was not confirmed with the change of the hue Become. Further, revealing the image was hiding changes in the hue, or Chigae the layer thickness and the constituent material of the birefringent transparent layer of lust paper endogenous sheet, more number of laminated layers and a metal reflective layer of birefringent transparent layer By changing the combination and the formation pattern, etc., it can be changed into various types. Therefore, it can also be suitably used as a true / false determination sheet, a true / false determining tool and a true / false determining method that can be used effectively for authenticity determination.

Hereinafter, the color information inherent sheet is referred to as a color change information inherent sheet.
Embodiments of the present invention will be described below. FIG. 1 is an explanatory diagram showing a schematic cross-sectional configuration of a color change information-incorporating sheet according to the present invention and the principle of verifying color change information in the color change information-incorporating sheet. FIG. 2 is an explanatory diagram showing a schematic cross-sectional configuration of another color change information-incorporating sheet according to the present invention and the verification principle of the color change information inherent in the color change information-inclusive sheet. FIG. 3 is an explanatory diagram showing the verification principle when the color change information of the color change information inherent sheet as shown in FIG. 2 is verified using a predetermined verification tool.

  The color change information-containing sheet shown in FIG. 1 has a birefringent transparent layer (101), and a metal reflective layer (102) is provided on the entire back side thereof. In addition, the color change information-containing sheet shown in FIG. 2 is a birefringent transparent laminated body in which two layers of a birefringent transparent layer (201) and a birefringent transparent layer (204) are laminated. A metal reflective layer (202) is provided on the entire back surface of the birefringent transparent laminate, and metal reflection is provided between the birefringent transparent layer (201) and the birefringent transparent layer (204). The layer (203) is provided with a metal reflective layer (205) in a part of the outermost layer. Further, the color change information-containing sheet shown in FIG. 3 is formed by laminating two layers of a birefringent transparent layer (301) and a birefringent transparent layer (304) in the same manner as the color change information-containing sheet shown in FIG. A birefringent transparent laminate is formed, and a metal reflective layer (302) is provided on the entire back surface of the birefringent transparent laminate, and the birefringent transparent layer (301) and birefringence are provided. A reflective metal layer (303) is provided between the transparent transparent layer (304) and a reflective metal layer (305) in a part of the outermost layer.

  The birefringent transparent layer (101, 201, 204, 301, 304) described above is a thin film layer made of a transparent material exhibiting birefringence, and is made of, for example, a plastic film produced by stretching. Can do. The plastic film produced by the stretching process exhibits birefringence because the molecules constituting the film are aligned in the stretching direction.

  Birefringence is a phenomenon that causes a phase difference between an extraordinary ray e (refractive index: ne) and an ordinary ray o (refractive index: no) when light is incident on a substance having a different refractive index depending on the optical axis direction. .

  This difference in refractive index between extraordinary rays and ordinary rays is called birefringence Δn. The birefringence Δn varies depending on the wavelength λ of light passing through the birefringent material. This is called birefringence wavelength dispersion and is expressed by the following equation.

Δn (λ) = ne−no
The phase difference value δ is proportional to the optical path length d passing through the birefringent material and is expressed by the following equation.

δ (λ) = Δn (λ) d

When the birefringent optical axis is parallel, the phase difference value δ is integrated even if the layers are divided into a plurality of layers, and in the case of a right angle direction, the phase difference value δ works in a direction that cancels out.

Here, with respect to the birefringent optical axis of the sheet in which the metal reflection layer is formed on the back side of the birefringent transparent layer having a retardation value δ, the angle of the optical axis of the polarizing plate is shifted by α and the light is superimposed. The reflectance is

R (λ, δ, α) = 1−sin2 (2απ / 180) · sin2 (2πδ (λ) / λ)

It is represented by

  That is, this shows that when α = 45 °, the amount of light reflected and returned is the lowest, and a hue change appears without the presence of a verification tool. It also shows that the reflectance changes depending on the wavelength, which means that the hue changes depending on δ and λ.

  For example, as shown in FIG. 1, each of the red component (104), green component (105), and blue component (106) of the light emitted from the light source (107) has a verification tool (linear polarizing plate) (103). It passes through the birefringent transparent layer (101), is reflected by the metal reflecting layer (102), and returns to the birefringent transparent layer (101) again. At this time, since the polarization state varies depending on the wavelength, it is divided into a green component (105) that can pass through the verification tool (linear polarizing plate) (103), a red component (104) that cannot pass through, and a blue component (106). As a result, only the light of the green component (105) reaches the observer (108). In short, when the observer (108) observes the color change information-containing sheet through the verification tool, the observer (108) can recognize it with a green hue.

  As described above, as the birefringent transparent layer, a plastic film produced by stretching can be used. This stretching process is a predetermined temperature in the range from the glass transition point to the melting point of the plastic. A processing method for producing a plastic film by stretching at a temperature, such as uniaxial stretching and biaxial stretching. In general, plastic is stretched to have birefringence, and at the same time, it becomes a uniform and tough film and is easy to handle. Plastics that form uniaxially or biaxially stretched plastic films include cellophane, polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET). ) Nylon and the like.

  Since biaxially stretched plastic films differ in the degree of stretching in the width direction, it is difficult to ensure uniform birefringence over the entire width, and it is difficult to use all of these as constituent materials for the birefringent transparent layer. If uniform birefringence is required in the width direction of the film, it is desirable to form the birefringent transparent layer with a uniaxially stretched plastic film.

  Further, the birefringence of the uniaxially stretched plastic film is Δn = 0.001 to 0.05, more preferably Δn = 0.0, taking into consideration the processing suitability and physical strength when forming the metal reflective layer described later. It may be in the range of 003 to 0.02. When the birefringence index Δn is larger than this value, the film thickness required to obtain a necessary retardation value becomes thin, which impairs processing suitability and causes slight distortion caused during processing. Since the possibility that the value deviates from the design value increases, it is not preferable. On the other hand, if the thickness is small, the film thickness required to obtain the retardation value is increased, which makes it difficult to process. Although it depends on the degree of stretching, this condition is satisfied when cellophane has a birefringence Δn of about 0.008, and polycarbonate has a birefringence Δn of about 0.003.

  A metal reflective layer (102) is provided on the back side of the birefringent transparent layer (101) having such a configuration, and a color change information-containing sheet having a laminated configuration is produced, and a verification tool (linear polarizing plate) is applied thereto. If the observation is repeated, the observer can recognize with a predetermined hue. The recognized hue can be changed variously according to the layer thickness of the birefringent transparent layer, and verification of the target sheet, for example, determination of authenticity can be performed with the change in hue.

  Incidentally, a polarizing plate (verification tool) is applied to the birefringent optical axis of the color change information-containing sheet formed by forming a metal reflection layer on the entire back side of the cellophane film (birefringent transparent layer) having birefringence. Table 1 shows the relationship between the thickness of the cellophane film, the optical path length, and the hue when the optical axis angles are shifted by 45 °.

Further, by providing a patterned metal reflective layer in a predetermined region on the surface side of the color change information inclusive sheet having such a configuration, a patterned metal reflective layer formed on the surface side and a metal formed on the back side The latent image can be contained by a combination of the reflective layer and the birefringent transparent layer disposed therebetween.

  That is, the metal reflective layer formed on the front side and the metal reflective layer formed on the back side are difficult to distinguish because the birefringent transparent layer is transparent simply by visual observation. However, when both are observed through a linear polarizing plate as a verification tool, the area of the metal reflective layer formed on the front side always appears white, but the hue of the area of the metal reflective layer formed on the back side changes. Therefore, since a contrast is created between the two, it is possible to visualize a latent image that has been difficult to visually recognize when visually observed. Further, it is also possible to apply the determination to the authenticity by using the result of confirming whether or not the latent image can be visualized in this way.

  Further, when the birefringent transparent layer is formed of a film having a λ / 4 retardation (in the case of cellophane, the thickness is about 21 μm), and a circularly polarizing plate is used as a verification tool, there is no anisotropy. Since the verification is based on circularly polarized light, the metal reflective layer on the front side is black and the metal reflective layer on the back side is white and can be recognized by the observer without matching the optical axis.

  In addition, the birefringent transparent layer is laminated in multiple layers, and a metallic reflective layer is provided on each of the back side, the interlayer, and the front side of the birefringent transparent layer, thereby changing the hue at a plurality of locations and a predetermined hue pattern. Appearance is possible.

  For example, as shown in FIG. 2, a birefringent transparent layer (201) made of a cellophane film having a thickness of 21 μm and a metal reflective layer (203) between layers on the metal reflective layer (202) on the back side, In a color change information-containing sheet in which a birefringent transparent layer (204) made of a cellophane film having a thickness of 35 μm and a metal reflective layer (205) on the surface side are laminated in this order, a straight line which is a verification tool Of the light (207, 208, 209) emitted from the light source (210) when the polarizing plate (206) is stacked, the light (207) reflected by the metal reflective layer (202) on the back side is A red color is exhibited in the same manner as when passing through a cellophane film having a thickness of 56 μm. In addition, the light (208) reflected by the metal reflective layer (203) between the layers passes through the portion of the cellophane film having a thickness of 35 μm, so that it is blue, and the light reflected by the reflective layer on the surface side (205) ( 209) does not pass through the birefringent transparent layer, and thus exhibits white, and the appearance of a predetermined hue pattern derived from various hue changes and the shape of the metal reflection layer provided in some areas. It is possible to go out.

  In addition, in order to adjust the hue presented when verifying the color change information, it is possible to use a verification tool in which a birefringent transparent layer is laminated on a linear polarizing plate. FIG. 3 shows the configuration of such a verification tool and the verification principle when verification is performed using this verification tool.

  The verification tool shown here is formed, for example, by laminating a birefringent transparent layer (306) made of a cellophane film having a thickness of 39 μm on a linear polarizing plate (307), and this is placed on the color change information-containing sheet. Of the light (308, 309, 310) emitted from the light source (311), the light (308) reflected by the metal reflective layer (302) on the back side has a cellophane thickness of 70 μm. The color is blue as if it had passed through the film. In addition, the light (309) reflected by the metal reflective layer (303) between the layers is red in the same manner as when passing through a cellophane film having a thickness of 56 μm, and is reflected by the reflective layer on the surface side (305) ( 310) exhibits a green color because it passes through a cellophane film having a thickness of 39 μm.

  Examples of the metal that can be used for each of the metal reflective layers described above include aluminum, tin, chromium, nickel, copper, gold, inconel, stainless steel, and duralumin.

  The metal reflective layer made of these metals is directly formed on a plastic film that becomes a birefringent transparent layer by vapor deposition or sputtering, or by transfer using a transfer foil having a metal reflective layer, and further metallic. What is necessary is just to form by the printing by ink, or the lamination of the film which has metal foil or a metal layer. In addition, when forming a patterned metal reflective layer such as the metal reflective layers 203, 205, 303, and 305, a patterning process is performed after the metal reflective layer is formed on the entire surface of the substrate. Alternatively, the patterned metal reflection may be transferred or laminated.

  Examples of a method for patterning these metal reflective layers include water-washed celite processing, etching processing, and laser processing.

  Washed sealight processing is done by printing a negative pattern on the base material in advance with water-washing ink, and then forming a metal reflection layer over the entire surface, and then washing the water-washing ink with water and simultaneously using the metal reflection layer. This is a method of forming a positive metal reflection pattern (metal reflection layer) by removing a part of the film.

  In the etching process, a metal reflective layer is first formed, a positive pattern made of a masking agent is formed thereon by printing, and then the unmasked portion is removed by using a corrosive liquid, thereby forming a patterned metal reflective layer. A method of forming a layer.

Laser processing is a method of forming a patterned metal reflection layer by forming a metal reflection layer on a substrate and then removing the metal reflection layer by applying a specific portion of intense laser light.
As a laser to be used, a high output Nd: YAG, CO2 gas laser is generally used.

  Examples of the present invention will be described below.

  Cellophane films having birefringence with thicknesses of 35 μm, 39 μm, and 56 μm were prepared, respectively, and a metal reflective layer made of aluminum with a thickness of 50 nm was formed on the entire back side of each cellophane film using a vacuum deposition method. Thus, a color change information-containing sheet according to Example 1 of the present invention was obtained.

  Then, when the linear polarizing plate as a verification tool was observed on the color change information-incorporating sheet, the color change information contained in each of the color change information-incorporated sheets was verified.

  A silver foil pattern was stamped on a part of the surface side of the cellophane film having a thickness of 21 μm by hot stamping. Further, a metal reflective layer made of aluminum having a thickness of 50 nm was formed on the entire back side by vacuum deposition, and a color change information-containing sheet according to Example 2 of the present invention was produced. The obtained color change information-containing sheet was observed in silver by normal visual observation. However, when the circular polarizing plate as a verification tool was overlapped and observed, the silver foil pattern part was black and the other part was white (silver ) A color and a black pattern corresponding to the shape of the silver foil pattern appeared.

  After coating the surface of the following film 1 with an adhesive made of vinyl chloride with a gravure coater with a film thickness of 1 μm, the following film 2 is placed on the metal reflective layer of the film 1 so that the pattern portion is on the top. The sheets were bonded together while being aligned by dry lamination to produce each color change information-containing sheet according to Example 3.

The obtained color change information-containing sheet was observed in silver by normal visual observation. However, when the verification tool having the following configuration was observed in an overlapping manner, the pattern printed with the metallic ink on the film 2 exhibited green, and the film 1 The pattern printed with metallic ink was red, the other parts were blue, a blue pattern appeared, and the underlying color change information could be verified.
<Film 1>
A film in which a pattern is printed with metallic ink on the surface side of a cellophane film having a thickness of 24 μm, and a metal reflective layer made of aluminum having a thickness of 50 nm is provided on the back side by a vacuum deposition method.
<Film 2>
A film produced by printing a pattern with metallic ink on the surface side of a cellophane film having a thickness of 17 μm.
<Verification tool>
A dedicated verification tool made by laminating a cellophane film with a thickness of 39 μm on a linear polarizing plate.

FIG. 3 is an explanatory diagram showing a schematic cross-sectional configuration of a color change information-incorporating sheet according to the present invention and a verification principle of color change information inherent in the color change information-inclusive sheet. It is explanatory drawing which shows the general | schematic cross-sectional structure of the other color change information inherent sheet | seat of this invention, and the verification principle of the color change information inherent in this color change information inherent sheet. FIG. 3 is an explanatory diagram showing a verification principle when the color change information of the color change information inherent sheet shown in FIG. 2 is verified using a predetermined verification tool.

101 Birefringent transparent layer 102 Metal reflective layer 103 on the back side Verification tool (linear polarizing plate)
104 105 106 Light 107 Light source 108 Observer 201 Birefringent transparent layer 202 Metal reflective layer 203 on the back side Metal reflective layer 204 between layers Birefringent transparent layer 205 Metal reflective layer 206 on the surface side Verifier (linear polarizing plate)
207 208 209 Light 210 Light source 211 Observer 301 Birefringent transparent layer 302 Metal reflective layer 303 on the back side Metal reflective layer 304 between layers Birefringent metal layer 305 Metal reflective layer 306 on the surface side Birefringent transparent layer 307 Linearly polarized light Plate 308 309 310 Light 311 Light source 312 Observer

Claims (8)

In addition to having a birefringent transparent layer, a metal reflective layer is provided in at least a part of the back side of the birefringent transparent layer, and has a plurality of birefringent transparent layers and the plurality of birefringent properties. A color information-containing sheet, wherein a metal reflective layer is provided in a partial region of an interlayer portion of the transparent layer . The color information-containing sheet according to claim 1, wherein a metal reflective layer is provided in a partial region on the surface side of the plurality of birefringent transparent layers. The color information- containing sheet according to claim 1, wherein the birefringent transparent layer is made of a stretched resin film. The color information-containing sheet according to any one of claims 1 to 3 , wherein the birefringent transparent layer is made of a uniaxially stretched resin film. Color information intrinsic sheet according to any one of claims 1 to 4, wherein said birefringent transparent layer is characterized in that it consists of cellophane film. Color information intrinsic sheet according to any one of claims 1 to 4, wherein said birefringent transparent layer is characterized in that it consists of polycarbonate film. A sheet-like laminated member for verifying the color information of the color information-containing sheet according to any one of claims 1 to 6 , wherein at least a birefringent transparent layer is laminated on the linearly polarizing plate, A verification tool, wherein the angle formed by the optical axis of the linearly polarizing plate and the optical axis of the birefringent transparent layer is set so as not to be 0 ° or 90 °. The linear information polarizing plate or the verification tool according to claim 7 is superimposed on the color information inherent sheet according to any one of claims 1 to 6, and the hue related to the color information inherent in the color information inherent sheet is changed. A method for verifying color change information, wherein the information content is verified visually by making the information visible.