JP2006155292A - Information recording medium with diffraction grating, and hidden information authentication device for information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording medium with diffraction grating, capable of surely performing truth-false determination even in a case that a substrate having micro diffracting grating elements having diffracting gratings on the surface has poor surface smoothness, and exhibiting a further high-level forgery preventive effect by making it difficult to discriminate an area recording predetermined hidden information, and a hidden information authentication device for the information recording medium. <P>SOLUTION: In this information recording medium, a plurality of micro diffracting grating elements having diffracting gratings on the surface are arranged on a substrate surface. The plurality of diffracting grating elements include a plurality of sets of diffracting grating element groups each composed of at least two or more diffracting grating elements with grating spaces and grating angles set so that diffracting light based on radiation of illuminating light from a light source having a predetermined area is converged to an identical convergence point in the space, and predetermined hidden information is patterned by a combination of the identical spatial convergence points corresponding to each diffracting grating element group. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an information recording medium having a diffraction grating in which a plurality of minute diffraction grating elements having a diffraction grating on the surface are arranged in a two-dimensional plane, and in particular, the smoothness of the substrate surface on which the minute diffraction grating elements are arranged. Even if it is bad, it is possible to authenticate the inherent concealment information and to determine its authenticity, and it is difficult to discriminate the area where the minute diffraction grating elements are arranged, making it even more sophisticated An information recording medium having a diffraction grating, which is capable of realizing an anti-counterfeiting effect, improving visibility as a display, and increasing freedom of design, and is concealed in the information recording medium The present invention relates to a concealment information authentication device for an information recording medium that authenticates concealment information that has been authenticated and can reliably determine its authenticity.

  Conventionally, an information recording medium such as a display having a diffraction grating pattern obtained by arranging a plurality of minute diffraction grating elements (dots) having a diffraction grating on a surface on a flat substrate has been used. Has been.

  Among these, an information recording medium having a diffraction grating pattern by two-beam interference is a photosensitive film in which minute interference fringes (hereinafter referred to as diffraction grating) by two-beam interference are changed in pitch, direction, and light intensity. In this way, it is obtained by successively exposing (see, for example, Patent Document 1).

  More specifically, the diffraction grating pattern is divided into a plurality of minute diffraction grating elements, and the pitch and spatial frequency of each diffraction grating element and the arrangement of the diffraction grating elements are appropriately changed. Further, the direction of the diffraction grating on the surface of the diffraction grating element is changed for each diffraction grating element.

  Further, as an information recording medium having a diffraction grating pattern, for example, an electron beam exposure apparatus is used, and an XY stage on which a planar substrate is placed is moved under the control of a computer, so that a minute diffraction grating element is formed on the surface of the substrate. An information recording medium on which a diffraction grating pattern with a predetermined pattern is formed, which is obtained by recording and arranging a plurality of patterns in a pattern, is also proposed (see, for example, Patent Document 2).

  By the way, as a method for determining the authenticity of an information recording medium having such a diffraction grating by using a verification machine, for example, a laser is applied to a portion of pattern information recorded in an array of minute diffraction grating elements (dots). A method is adopted in which diffracted light is obtained by irradiating light, etc., which is read and recorded by a sensor, and authenticity is determined based thereon.

  In addition, a method has been proposed in which information is recorded as a pattern that cannot be observed with the naked eye or a pattern that cannot be identified, and the authenticity is determined by reading the information using a reader using a laser beam.

  However, when authenticity is determined by such a method, if the diffraction grating pattern of the information recording medium to be determined is formed on the paper by transfer using a transfer foil, the flatness of the paper to be transferred Since the transfer foil is bent along the unevenness of the paper surface, the uneven state and pattern of the diffraction grating on the transfer foil are not faithfully transferred / reproduced on the paper, so that a correct reproduced image can be obtained at the time of judgment. It was difficult to read the information clearly.

Furthermore, since an information recording medium having a diffraction grating obtained by such transfer records information in a specific area, an area where information is easily recorded can be found with an observation device such as a magnifying glass. If the angle at which the laser beam is irradiated can be determined, it becomes possible to create a counterfeit product based on the information.
JP 60-156004 A US Pat. No. 5,058,992

  The present invention has been made in view of the above-described problems, and even when the surface smoothness of a substrate having a minute diffraction grating element having a diffraction grating on the surface is poor, it is possible to reliably perform authenticity determination. At the same time, it is difficult to discriminate the area where the predetermined concealment information is recorded, and a more advanced anti-counterfeit effect is realized, improving the visibility as a display and increasing the degree of freedom of design. Another object of the present invention is to provide an information recording medium having a diffraction grating and a concealed information authentication device for the information recording medium.

  In order to solve the above problems, the invention according to claim 1 is characterized in that a plurality of minute diffraction grating elements having a diffraction grating on the surface are arranged on the surface of the substrate, and the plurality of diffraction grating elements are And at least two or more diffraction gratings whose grating intervals and grating angles are set so that diffracted light based on illumination light from a light source having a predetermined area is condensed at the same condensing point in space. A plurality of sets of diffraction grating element groups that are combinations of elements are included, and predetermined concealment information is patterned by the sum of reproduction information at the same focusing point on the space corresponding to each diffraction grating element group. An information recording medium having a diffraction grating.

  According to a second aspect of the present invention, in the information recording medium having the diffraction grating according to the first aspect, the structure of the diffraction grating of the minute diffraction grating element includes a blazed diffraction grating shape.

  Furthermore, in the invention according to claim 3, in the information recording medium having the diffraction grating according to claim 1 or 2, the structure of the diffraction grating of the minute diffraction grating element includes an uneven shape of the light scattering element. It is characterized by.

  Furthermore, in the invention described in claim 4, a plurality of minute diffraction grating elements having diffraction gratings on the surface are arranged on the substrate surface, and the plurality of diffraction grating elements have a predetermined area. A combination of at least two diffraction grating elements whose grating interval and grating angle are set so that the diffracted light when irradiated with illumination light from the light source is collected at the same condensing point in space. And a plurality of sets of diffraction grating element groups to be patterned as predetermined concealment information by the sum of reproduction information at the same condensing point on the space corresponding to each diffraction grating element group. An apparatus for authenticating the authenticity of a characteristic diffraction grating and an information recording medium having concealment information, a light source having a predetermined area, and condensing diffracted light based on illumination light from the light source to the diffraction grating element Point combination Accordingly, an information recording medium comprising at least concealment information reading means for reading the concealment information to be patterned and determination means for determining authenticity based on information from the concealment information reading means This is a concealment information authentication device.

Still further, the invention according to claim 5 is the information recording medium concealment information authentication device according to claim 4, wherein the illumination light from the light source having the predetermined area is irradiated to the diffraction grating element and diffracted. A projection screen for forming a diffraction image is disposed in the vicinity of a condensing point to be condensed later, and the concealment information reading unit reads the diffraction image formed on the projection screen and converts it into an electrical signal. It is characterized by that.

  Furthermore, in the invention according to claim 6, in the concealed information authentication device for information recording medium according to claim 4, illumination light from the light source having the predetermined area is irradiated to the diffraction grating element and diffracted. It is characterized in that the focal position of the imaging lens of the concealment information reading means is set to coincide with the vicinity of the condensing point that arrives later.

  Furthermore, the invention according to claim 7 is the information recording medium concealment information authentication device according to any one of claims 4 to 6, wherein the light source having the predetermined area is a cold cathode tube or a light emitting diode, The light source is a flat light source that is a combination of a reflector and a light guide plate, and is characterized in that a light shielding means for shielding a specific shape portion is provided on the front surface thereof.

  Furthermore, the invention described in claim 8 is the information recording medium concealment information authenticating apparatus according to claim 7, wherein the light shielding means for shielding the specific shape portion is a liquid crystal panel.

  Furthermore, the invention according to claim 9 is the information recording medium concealment information authentication device according to any one of claims 4 to 8, wherein a plurality of light sources having a predetermined area and each light source are switched to be predetermined. The switching means for selectively irradiating the diffraction grating element group with the illumination light, and the switching means is operated to sequentially irradiate the diffraction grating element group with the illumination light, and the light is condensed after being diffracted there. And a reading means for reading data of predetermined concealment information from the combination of the respective condensing points projected on the projection screen.

  Furthermore, the invention according to claim 10 is the information recording medium concealment information authenticating device according to claim 9, wherein the light emitting surfaces of the plurality of light sources having the predetermined area have different shapes. Features.

  The information recording medium having the diffraction grating of the present invention can reliably determine the authenticity even when the smoothness of the substrate surface on which the fine diffraction grating element is arranged is poor, and the fine diffraction grating element is arranged. It is difficult to discriminate the region, and a more advanced anti-counterfeiting effect can be realized, improving the visibility as a display and increasing the degree of freedom of design.

  In addition, the concealed information authentication device for an information recording medium of the present invention reduces the influence of unevenness on the diffraction grating element arrangement surface of the information recording medium to be determined authenticity by illuminating with a light source having a predetermined area. Therefore, it is possible to reliably recognize and determine the concealment information that exists.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a schematic configuration of an information recording medium having a diffraction grating of the present invention and a schematic configuration of a concealed information authentication apparatus for an information recording medium for determining the authenticity of the information recording medium having the diffraction grating. It is.

In the information recording medium 11 having a diffraction grating, a plurality of minute diffraction grating elements having a diffraction grating on the surface are arranged on the surface of the substrate 10, and the plurality of diffraction grating elements have a predetermined area. A combination of at least two or more diffraction grating elements whose grating spacing and grating angle are set so that the diffracted light when irradiated with the illumination light from the light source 12 is collected at the same condensing point in space. A plurality of sets of diffraction grating element groups to be included, and predetermined concealment information is patterned by the reproduction information sum at the same light collection point on the space corresponding to each diffraction grating element group.

  More specifically, in the information recording medium 11 having this diffraction grating, a plurality (1a, 1b, 1c, 1d) of minute diffraction grating elements having a diffraction grating on the surface are arranged on the surface of the substrate 10. The diffraction grating elements 1a and 1b constitute one diffraction grating element group, and the diffraction grating elements 1c and 1d constitute another diffraction grating element group.

  Among the plurality of sets of diffraction grating element groups, the diffraction grating elements 1a and 1b of one diffraction grating element group are such that the diffracted light when irradiated with illumination light from the light source 12 having a predetermined area is in space. The diffraction grating elements 1c and 1d of the other diffraction grating element group are diffracted light when irradiated with illumination light from the light source 12 having a predetermined area so that the light is condensed on the same condensing point 14a. And the grating interval and the grating angle are respectively set so that the light is condensed at the same light condensing point 14b in the space. The information recording medium 11 having diffraction gratings includes a plurality of sets of diffraction grating element groups that are combinations of at least two of these diffraction grating elements, and the same collection in the space corresponding to each diffraction grating element group. Predetermined concealment information is patterned by the reproduction information sum at the light spot.

  On the other hand, the information recording medium concealment information authenticating apparatus is an apparatus for authenticating the authenticity of the information recording medium 11 having the diffraction grating having the above-described configuration. Concealment information reading means 15 for reading concealment information that is patterned only by irradiating illumination light to the diffraction grating elements 1a, 1b, 1c, and 1d on the information recording medium 11 having the diffraction grating of the invention, and this concealment It comprises at least judging means 16 for judging authenticity based on information from the information reading means 15.

  In FIG. 1, illumination light from a light source 12 having a predetermined planar area is diffracted at diffraction angles set by the diffraction grating elements 1a, 1b, 1c, and 1d, and is condensed at a condensing point in space. Then, a diffraction image is projected on the projection screen 13. At this time, the light diffracted by the diffraction grating element 1a and the diffraction grating element 1b is condensed on the condensing point 14a, and the light diffracted by the diffraction grating element 1c and the diffraction grating element 1d is condensed on the condensing point 14b. Thus, the grating interval and grating angle of the diffraction grating element are set.

  Further, diffraction grating elements (not shown) other than the diffraction grating element 1a, the diffraction grating element 1b, the diffraction grating element 1c, and the diffraction grating element 1d of the information recording medium 11 having this diffraction grating have a condensing point 1a and a condensing point. The light is not focused on the point 1b. For this reason, illuminating light from the light source 12 illuminates the information recording medium 11 having a diffraction grating, so that the diffracted light from each of the diffraction grating elements is collected on the light condensing points 14a and 14b on the projection screen 13, respectively. Light is projected, and predetermined concealment information is patterned by a combination thereof.

  In the information recording medium having the diffraction grating of the present invention, as described above, a plurality of identical points such as the condensing point 14a and the condensing point 14b are arranged, and a predetermined value is determined by a combination of these same points. The concealment information is patterned (appears), and the concealment information reading means can recognize its presence. In the example shown in FIG. 1, concealment information is projected on the projection screen 13, and authenticity can be determined by confirming this projection pattern.

  When performing such authentication, if the diffraction grating elements on the information recording medium are formed on the paper by transfer using the transfer foil, the irregularities of the diffraction grating elements on the transfer foil are If it becomes a surface shape along the uneven shape, the diffracted light from the diffraction grating element that composes it is not emitted at the initially calculated angle, and when a light beam with a small area such as laser light is incident, Diffracted light becomes broad, and fluctuations in the emission angle become large, and even if the irradiation position is changed slightly, the emission angle fluctuates greatly. Will make the determination of authenticity inaccurate.

  However, when the illuminating information recognition apparatus having the configuration shown in FIG. 1 is used to illuminate with a light source (surface light source) having a predetermined area, the concavo-convex shape on the surface of the substrate is compared with the case of illuminating with a point light source. Since the fluctuation of the emission angle is reduced and the diffracted light is reliably condensed at a desired condensing point, reading by the concealment information reading means such as an image sensor is performed accurately.

  In addition, when the diffraction grating elements for condensing the diffracted light at the same point are arranged on the substrate 10, information for performing authenticity determination is obtained by irregularly arranging the diffraction grating elements that are responsible for patterning the concealment information. Discrimination of the recorded area can be made difficult.

  In addition, the diffraction grating structure of a minute diffraction grating element includes a saw blade-shaped blazed diffraction grating shape, thereby diffracting light that is diffracted to other than the same point in space (-1st order diffracted light or 2nd order diffracted light) Therefore, the concealment information can be reliably read, and more accurate authentication can be performed.

  Furthermore, by making the diffraction grating structure of a minute diffraction grating element include the uneven shape of the light scattering element, it is possible to combine diffracted light and scattered light, and to make the arrangement of the diffraction grating elements more complicated. And it is more difficult to decipher the specific pattern from the array of diffraction grating elements.

  On the other hand, FIG. 2 is an explanatory view schematically showing a schematic configuration of another concealment information authentication apparatus of the present invention and a concealment information authentication method performed using this apparatus.

  The concealment information authentication device includes a plurality of light sources 22 and 23 having a predetermined area, and switching means 19a and 19b for switching the light sources 22 and 23 to irradiate a predetermined diffraction grating element group with illumination light, Each of the switching means 19a and 19b is operated to sequentially irradiate illumination light to each diffraction grating element group, and projecting screens 24 for projecting the respective condensing points to be condensed after being diffracted, and the projection screen 24 And at least concealment information reading means (lens 25, image sensor 26, etc.) for reading data of predetermined concealment information from the combination of the respective condensing points 28a and 28b projected onto.

  The light source 22 and the light source 23 are planar light sources having areas of different shapes. The illumination light irradiated from the light source 22 is diffracted by the diffraction grating element 2a and the diffraction grating element 2b, and is condensed on the condensing point 28a. Moreover, the illumination light irradiated from the light source 23 is diffracted by the diffraction grating element 2c and the diffraction grating element 2d, and is condensed on the condensing point 28b.

  A projection screen 24 is disposed in the vicinity of the condensing point 28a and the condensing point 28b in the space, and a diffraction image is projected thereon, and concealment information is patterned by a combination thereof. The structure of the concealment information patterned in this way is more complicated than that shown in FIG. 1, and can be made more difficult to decipher.

The concealment information patterned by the combination of the condensing points 28a and 28b is recorded on the image sensor 26 as the concealment information 27 by using an image projected on the projection screen 24 via the lens 25 constituting the concealment information reading means. To do. Then, a predetermined calculation can be performed from the recorded data, and the determination means 29 can determine authenticity.

  Also in this concealment information authentication device, the light source 22 and the light source 23 are light sources having areas, so that the fluctuation of the emission angle of the diffracted light from the diffraction grating element of the information recording medium to be determined authenticity is reduced, The concealment information that can reliably determine the authenticity is projected on the projection screen 24 in a pattern.

  In addition, as described in the example shown in FIG. 1, when the diffraction grating elements that focus on the same point are arranged on the substrate 20, the diffraction grating elements that are responsible for patterning the concealment information are irregularly arranged. As a result, in the information recording medium 21, it is difficult to determine an area in which information for authenticity determination is recorded.

  Further, as a method of reading concealment information, the switching means 19a is operated without irradiating the light source 22 and the light source 23 at the same time. First, the illumination light is irradiated only from the light source 22 and is diffracted by the diffraction grating elements 2a and 2b. The light is condensed at the condensing point 28 a, the diffraction image is projected onto the projection screen 24, and is read as one piece of concealment information by the image sensor 26. Next, the switching means 19b is operated to irradiate illumination light only from the light source 23, and the light diffracted by the diffraction grating elements 2c and 2d is condensed on the condensing point 28b, and the diffraction image is projected onto the projection screen 24. The image sensor 26 reads the other data of the concealment information. Then, by using these two pieces of read data and performing arithmetic processing between the respective data, etc., the authenticating determination is performed by the determining means 29, so that a more advanced authenticity determination can be performed.

  On the other hand, FIG. 3 is an explanatory view schematically showing a schematic configuration of still another concealment information authenticating apparatus of the present invention and a concealing information authenticating method performed using this apparatus.

  In the concealed information authentication apparatus shown in FIG. 3, the light source that illuminates the information recording medium 31 having the diffraction grating is the light emitted from the light emitting diode 32 as a uniform surface light source by the light guide reflection plate 33, and then the liquid crystal panel 34. The diffraction grating element is illuminated with the transmitted light. In short, this light source is provided with means for shielding a specific shape portion.

  The illumination light emitted from the light source to each of the diffraction grating element 3a, the diffraction grating element 3b, the diffraction grating element 3c, and the diffraction grating element 3d is diffracted by each diffraction grating element and collected at a condensing point 36 in space. Shine.

  A lens 35 is arranged in the vicinity of the condensing point 36 so that the focal position thereof coincides, and the concealment information 38 can be directly imaged on the image sensor 37 of the concealment information reading means. The image pickup device 37 takes in the image data and performs a predetermined calculation from the image data, whereby the determination means 39 can determine the authenticity.

  Here, the light guide reflection plate 33 acts as a light source having an area, and tries to determine authenticity by illuminating the diffraction grating element with illumination light transmitted through the liquid crystal panel 34 (light from a flat light source). Variations in the exit angle of the diffracted light from the diffraction grating elements of the information recording medium are reduced, and concealment information that can be reliably determined for authenticity is projected in a pattern on the projection screen 24.

In addition, by displaying a pattern on the liquid crystal panel 34, it is possible to freely set the size, shape, and position of the light source. By switching these light sources, a plurality of concealment information is formed into a pattern, and the information is imaged. It is possible to perform true / false judgment by taking in from the element and performing predetermined arithmetic processing. That is, a complicated light source shape can be set, and more sophisticated concealment information authentication can be performed.

FIG. 2 is an explanatory diagram showing a schematic configuration of an information recording medium having a diffraction grating pattern of the present invention and a schematic configuration of a concealed information authentication apparatus for an information recording medium for determining the authenticity of the information recording medium having the diffraction grating pattern. is there. It is explanatory drawing which shows the other structure of the concealment information authentication apparatus of the information recording medium for determining the authenticity of the information recording medium which has a diffraction grating pattern of this invention. It is explanatory drawing which shows the further another structure of the concealment information authentication apparatus of the information recording medium for determining the authenticity of the information recording medium which has a diffraction grating pattern of this invention.

Explanation of symbols

1a, 1b, 1c, 1d ... diffraction grating elements 2a, 2b, 2c, 2d ... diffraction grating elements 3a, 3b, 3c, 3d ... diffraction grating elements 10, 20, 30 ... substrate 11, 21, 31... Information recording medium 12, 22, 23, having diffraction grating, light sources 14 a, 14 b, 28 a, 28 b, 36, focusing points 13, 24, projection screens 16, 29, 39 ... Determination means

Claims (10)

  A plurality of minute diffraction grating elements having a diffraction grating on the surface are arranged on the surface of the substrate. These diffraction grating elements receive diffraction light based on illumination light from a light source having a predetermined area. Including a plurality of sets of diffraction grating elements that are combinations of at least two or more diffraction grating elements whose grating intervals and grating angles are set so as to collect light at the same light collection point in space; An information recording medium having a diffraction grating, wherein predetermined concealment information is patterned by a sum of reproduction information at the same condensing point on a space corresponding to each diffraction grating element group.   2. The information recording medium having a diffraction grating according to claim 1, wherein the structure of the diffraction grating of the minute diffraction grating element includes a blazed diffraction grating shape.   The information recording medium having a diffraction grating according to claim 1 or 2, wherein the structure of the diffraction grating of the minute diffraction grating element includes an uneven shape of the light scattering element.   A plurality of minute diffraction grating elements having a diffraction grating on the surface are arranged on the substrate surface, and the plurality of diffraction grating elements are diffracted when illumination light from a light source having a predetermined area is irradiated. It includes a plurality of sets of diffraction grating elements that are combinations of at least two or more diffraction grating elements whose grating intervals and grating angles are set so that light is collected at the same light collection point in space. In addition, the authenticity of the information recording medium having a diffraction grating is characterized in that it is patterned as predetermined concealment information by the sum of reproduction information at the same condensing point on the space corresponding to each diffraction grating element group. For reading concealment information patterned by a combination of a light source having a predetermined area and a condensing point of diffracted light based on illumination light from the light source to a diffraction grating element And concealing information reading means, the concealment information authentication device of the information recording medium, characterized by including at least a and judging means for judging authenticity based on the information from this concealment information reading means.   A projection screen for forming a diffraction image is arranged in the vicinity of a condensing point where the illumination light from the light source having the predetermined area is irradiated onto the diffraction grating element and condensed after being diffracted. 5. The concealment information authentication device for an information recording medium according to claim 4, wherein the concealment information reading means reads the diffraction image formed on the projection screen and converts it into an electric signal.   Illumination light from the light source having the predetermined area is applied to the diffraction grating element, and is set so that the focal position of the imaging lens of the concealment information reading means coincides with the vicinity of the condensing point that arrives after being diffracted. The concealment information authentication device for an information recording medium according to claim 4.   The light source having the predetermined area is a flat light source formed by combining a cold cathode tube or a light emitting diode, a reflecting plate, and a light guide plate, and a light shielding means for shielding a specific shape portion is provided on the front surface thereof. The concealed information authentication device for an information recording medium according to any one of claims 4 to 6.   8. The hidden information authentication apparatus for an information recording medium according to claim 7, wherein the light shielding means for shielding the specific shape portion is a liquid crystal panel. A plurality of light sources having a predetermined area, switching means for selectively irradiating illumination light to a predetermined diffraction grating element group by switching each light source, and operating the switching means to sequentially form the diffraction grating element group Data of predetermined concealment information is obtained from a combination of a projection screen for projecting each of the condensing points to be collected after being irradiated with illumination light and diffracted there, and the respective condensing points projected on the projection screen. 9. The concealment information authentication device for an information recording medium according to claim 4, further comprising concealment information reading means for reading.   10. The concealed information authentication device for an information recording medium according to claim 9, wherein the light emitting surfaces of the plurality of light sources having the predetermined area have different shapes.

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