JP4876853B2 - OVD medium and printed information including OVD medium - Google Patents

Description

  The present invention relates to an OVD medium having a concavo-convex pattern for displaying a first image by light interference and / or diffraction.

  Conventionally, an optically variable device (OVD) medium such as a hologram, a diffraction grating, or a multi-layered thin film that causes a color change (color shift) depending on a viewing angle, uses a three-dimensional image using light diffraction and interference. It can express special decoration images that shine in rainbow colors, and is used in general printed materials such as various decoration materials, picture books, and catalogs. Furthermore, these OVDs have characteristic visual effects and require advanced manufacturing techniques, so they are formed on a part or the entire surface of printed information such as credit cards, securities, certificates, etc., and are protected against forgery. Used as a medium.

  An OVD medium such as a hologram or a diffraction grating has a structure such as a fine concavo-convex pattern or a striped pattern having a different refractive index, and an image or color depending on the viewing angle or illumination angle due to light interference or diffraction. A change (color shift) occurs. An OVD made of a multilayer thin film has a structure in which ceramics and metals having different optical characteristics are laminated in layers. This multilayer thin film utilizes the optical characteristics of the constituent materials and the light interference effect obtained by the thin film, and has reflection / transmission characteristics in a specific wavelength range, so that a color shift occurs depending on the observation angle.

  Holograms can be divided into relief holograms and volume holograms depending on the production method. Of these, relief holograms are based on optical projection methods using laser light interference, or fine uneven patterns produced by electron beam drawing. It is formed using a relief type original plate. A metal stamper is produced from this original plate by a method such as electroforming, and a thermoplastic resin, a photocurable resin, or the like is applied to a planar substrate such as PET using the metal stamper as a matrix, and a metal stamper The resin is cured by applying heat and light and the hologram pattern is duplicated.

  The relief-type diffraction grating pattern can change the display image or display a three-dimensional image according to the observation angle by controlling the direction, angle, brightness, and the like of diffracting light. .

As diffraction grating parameters,
(1) Spatial frequency of diffraction grating (pitch of grating line: number of grating lines per unit length)
(2) Direction of diffraction grating (direction of grating line)
(3) Diffraction grating drawing area (arrangement of diffraction grating cells)
There are three,
In accordance with (1), the color at which the diffraction grating pattern appears shining with respect to a fixed point changes,
In accordance with (2), the direction in which the diffraction grating cell appears shining changes,
In accordance with (3), a display image (picture, character, symbol, etc.) is determined.

  By dividing the surface of the substrate into an array and forming a diffraction grating in which the above parameters are changed for each of the divided elements (cells), a display image having a directional gloss can be formed. (For example, patent document 1).

  Such a diffraction grating can be manufactured by a method similar to that of a relief hologram, but a photosensitive resist is applied by computer control using an electron beam exposure apparatus as disclosed in Patent Documents 2 and 3. There is also a method of forming a diffraction grating pattern on the surface of the substrate by moving an XY stage on which the planar substrate thus placed is moved.

FIG. 10 shows an example of an OVD medium having a pattern forming layer 24 in which a relief hologram pattern or a diffraction grating pattern is formed on a base material. When the OVD medium is used, the pattern forming layer 24 is usually transparent. Therefore, as shown in FIG. 11, the light reflecting layer 25 is formed on the pattern forming surface by a method such as vapor deposition of a thin film layer of metal such as aluminum or dielectric. In general, it is pasted on a base material 23 such as paper or a plastic plate via an adhesive layer 26. As shown in FIG. 11, when an OVD medium (pattern forming layer 24) is affixed to an information printed matter 27 such as cards, securities, certificates, etc., a printing layer (not shown) or A protective layer (not shown) is provided to prevent the hologram pattern or diffraction grating pattern forming layer from being soiled or scratched.
Japanese Patent No. 3283582 Japanese Patent Laid-Open No. 2-72315 US Pat. No. 5,058,992

  As described above, OVD media has a characteristic visual effect and requires advanced technology for manufacturing. Therefore, as an effective means for preventing counterfeiting, credit cards, securities, certificates, etc. It is provided on part or the entire surface of printed information. However, forgery of OVD media having a fine concavo-convex structure has become impossible due to the recent generalization of the production of fine concavo-convex patterns and the improvement of analysis technology of the fine concavo-convex structure.

  Therefore, the present invention makes it easy to determine authenticity by displaying different designs, characters, symbols, etc. depending on the viewing angle, makes analysis of the structure of these OVD media more difficult, and further enhances the forgery prevention effect. It is an object of the present invention to provide an OVD medium that can be used and an information printed matter including the OVD medium.

According to the first aspect of the present invention, the surface has a pattern forming layer in which a plurality of cells each having a uniform concavo-convex pattern for displaying a first image by light interference and / or diffraction is formed on the surface, Oite the part of the uneven pattern to display the first image, consisting of the concavo-convex pattern having a height and / or depth different from the height and / or depth of the concavo-convex pattern, first it does not depend on the cell structure 2 is provided, and the concavo-convex pattern of the second image display area has a line segment connecting the apex of the convex part or the bottom point of the bottom part parallel to the pattern non-formation surface of the pattern forming layer. a fixed pattern portion comprising a substantially straight, the constant from pattern portion to the concavo-convex pattern to display the first image leads to, have a height and / or increasing or decreasing the transition portion depth Characterized, the height, the a distance from the apex of the convex portion of the concavo-convex pattern to the pattern non-forming surface of the pattern forming layer, the depth, the bottom point of the concave portion from the apex of the convex portion of the concavo-convex pattern An OVD medium is provided that is a distance up to .

  In the present invention, the first image and the second image may be an integral image or separate images.

In the present invention, a difference in height and / or depth between the uneven pattern of the first image display area and the uneven pattern of the fixed pattern portion in the second image display area is 10 nm or more, and. It can be 3 mm or less.

According to a second aspect of the present invention, there is provided an information printed matter comprising the OVD medium of the present invention.

  According to the present invention, it is possible to display the image of the second image display region even at an angle at which the diffracted light of the concave-convex pattern constituting the first image display region is not visible, thereby further facilitating the authenticity determination. It becomes possible.

  In addition, by changing the height and / or depth of the concavo-convex pattern, it is possible to change the visibility of images such as displayed patterns, characters and symbols. As a result, when the OVD medium is observed at an angle where the light diffracted by the concavo-convex pattern constituting the first image display area is at a strong angle, the second image is difficult to see, or the concavo-convex pattern constituting the first image display area. The second image can be clearly observed when the light diffracted by is observed at a weak angle.

  Further, when the first image display area has a plurality of cells, the combination with the second image display area makes it difficult to analyze the structure and further enhance the forgery prevention effect.

  The first image and the second image can constitute one integrated image or separate images (pictures, characters, symbols, etc.). That is, not only the first image but also the second image (pattern, character, symbol, etc.) can be displayed in combination.

  Further, when the uneven pattern of the second image display area has a transition portion in which the height and / or depth gradually increases or decreases, the outline of the second image (picture, character, symbol, etc.) may be blurred. Even if the concavo-convex pattern is magnified and observed with a microscope or the like, the outline is not clear, so that the analysis of the shape and structure becomes difficult.

  In addition, when the uneven pattern of the second image display area has a constant pattern portion in which a line segment connecting the apex of the convex part or the bottom point of the bottom part is a substantially straight line, it is easy to produce the uneven pattern. It becomes possible.

  Further, the uneven pattern of the second image display area has a constant pattern portion in which a line segment connecting the vertex of the convex portion or the bottom point of the bottom portion is a substantially straight line, and the straight line is a pattern of the pattern forming layer. If it is parallel to the non-formation surface, the outline of the second image can be clearly displayed, and the authenticity determination can be facilitated.

  Further, the uneven pattern of the second image display region is gradually increased or decreased in height and / or depth with a constant pattern portion in which a line segment connecting the vertex of the convex portion or the bottom point of the bottom portion is a substantially straight line. When the transition portion is included, it is possible to further improve the forgery prevention effect and the ease of authenticity determination.

  Furthermore, when the height and / or depth difference between the uneven pattern of the first image display area and the uneven pattern of the second image display area is 10 nm or more and 0.3 mm or less, the first The second image can be viewed at an angle at which the diffracted light from the concavo-convex pattern constituting the image display area is not visible, and the thickness of the OVD medium does not become too thick.

  Since the information printed matter such as securities, cards, certificates and the like of the present invention is provided with the OVD medium of the present invention, it is possible to improve the forgery prevention effect and the ease of authenticity determination.

  In the present invention, the uneven pattern includes a relief hologram pattern and a diffraction grating pattern. The highest point of the convex part of the concavo-convex pattern is called the apex, and the lowest point of the concave part is called the bottom point. The height and depth of the concavo-convex pattern will be described with reference to FIG. 10. The height of the concavo-convex pattern refers to the pattern non-formation surface 24a of the pattern formation layer from the top of the convexity (in other words, the pattern formation layer 24 and the substrate 23). The depth 28 of the concavo-convex pattern means the distance 29 from the top of the convex portion to the bottom point of the concave portion.

  Hereinafter, various embodiments of the OVD medium of the present invention will be described with reference to the drawings. Throughout the drawings, like members and elements are given like reference numerals.

  FIG. 1 is a plan view showing an OVD medium 10 according to the first embodiment of the present invention, and FIG. 2 is an enlarged view showing a cross section taken along line X-X ′ in FIG. 1.

  The OVD medium 10 includes a circular region 13 (second image display region) in a part of the entire uniform diffraction grating pattern 11 (first image display region) formed on the surface of the pattern forming layer 24 (FIG. 2). Another diffraction grating pattern 131 (FIG. 2) is formed so as to constitute The pattern forming layer 24 is attached on the base material 23.

  The diffraction grating pattern 11 is formed, for example, with a spatial frequency of 500 lines / mm and a concave / convex pattern depth of 200 nm, and the diffraction grating pattern 131 in the circular region 13 has a spatial frequency of 500 lines / mm and the concave / convex pattern depth of 200 nm. However, as shown in FIG. 2, the height difference between the diffraction grating pattern 11 and the diffraction grating pattern 131 in the circular region 13 is, for example, 100 nm (diffraction in the circular 13 region). (The lattice pattern 131 is lower in height). The circle 13 is perceived by this height difference. In the OVD medium 10, when the diffracted light by the diffraction grating pattern 11 is viewed at a strong angle, it is difficult to visually recognize the pattern of the circle 13. However, the pattern of the circle 13 can be confirmed at an angle where the diffracted light by the diffraction grating pattern 11 is weak. By changing the displayed picture depending on the difference in the observation angle, it is possible to facilitate the authenticity determination.

  An OVD medium similar to the OVD medium 10 shown in FIG. 1 can also be obtained by changing the depth of the diffraction grating pattern in the circular region (second embodiment). That is, as shown in FIG. 3, which is a cross-sectional view similar to FIG. 2, for example, unevenness is formed on a part of the diffraction grating pattern 11 that is uniformly formed on the entire surface with a spatial frequency of 500 lines / mm and an unevenness pattern depth of 200 nm. Although the pattern height is the same, a circular pattern corresponding to the circle 13 shown in FIG. 1 can be similarly displayed by providing the diffraction grating pattern 132 having a depth of about 100 nm.

  1 to 3, a diffraction grating having uniform parameters over the entire surface is used as the diffraction grating pattern 11, but the uneven pattern (that is, the diffraction grating pattern and the hologram pattern) in the present invention has various parameters inside. By changing, not only a uniform display image on the entire surface but also an image such as a pattern, a character, a symbol, etc. can be displayed.

  FIG. 4 is a plan view showing an example of the OVD medium 20 according to the third embodiment of the present invention, FIG. 5 is an enlarged view of a section of the portion, and FIG. It is a top view which expands and shows a part of.

  The OVD medium 20 forms a circular region 13 ′ that does not depend on the cell structure in a part of the diffraction grating pattern 12 that is divided into a plurality of uniform cells 21 formed on the entire surface of the pattern forming layer 24. Another diffraction grating pattern 131 ′ is formed. The diffraction grating pattern 12 constituting the cell 21 is formed with, for example, a spatial frequency of 500 lines / mm and a concave / convex pattern depth of 200 nm, and the diffraction grating pattern 131 ′ forming the circular region 13 ′ has a spatial frequency of 500 lines / mm, concave / convex. The depth of the pattern is also formed at 200 nm.

  FIG. 5 is a cross-sectional view including the boundary between the diffraction grating pattern 12 and the circular region 13. As shown in FIG. 5, the diffraction grating pattern 131 ′ constituting the circular region 13 ′ includes a constant pattern portion 131′a in which the height and depth of the concavo-convex pattern are constant (not changed), and a ground diffraction grating pattern. 12 includes a transition portion 131′b whose height gradually decreases from 12 to the constant pattern portion 131′a (in other words, the transition portion 131′b moves from the constant pattern portion 131′a to the diffraction grating pattern 12). The height is gradually increasing.) By having such a transition portion 131 ′ b, the boundary between the pattern of the diffraction grating pattern 12 having a cell structure and the circle 13 ′ is blurred, and a circle pattern with an unclear outline is displayed. That is, when the enlarged observation is performed as shown in FIG. 6, the outline of the pattern of the circle 13 that does not depend on the cell structure becomes unclear and unclear. Thereby, analysis of the structure with a microscope or the like is also difficult when visually observed because the height and / or depth of the concavo-convex pattern gradually changes as shown in FIG.

  FIG. 7 is a plan view of an OVD medium 30 according to the fourth embodiment of the present invention, and FIG. 8 is an enlarged view of the section of the portion.

  As shown in FIG. 4, the OVD medium 30 includes a triangular region that does not depend on the cell structure, in a part of the diffraction grating pattern 12 that is formed on the surface of the pattern formation layer 24 and is divided into a plurality of cells 21 that are uniform over the entire surface. Another diffraction grating pattern 141 is formed so as to form 14.

  The diffraction grating pattern 12 constituting the cell 21 is formed with, for example, a spatial frequency of 500 lines / mm and a concave / convex pattern depth of 200 nm, and the diffraction grating pattern 141 forming the triangular area 14 has a concave / convex pattern with a spatial frequency of 500 lines / mm. It is formed with a depth of 300 nm, and the height of the convex portion is 500 nm lower than the height of the diffraction grating pattern 12. Here, the line segment 15 connecting the vertices a to f of the convex part of the diffraction grating pattern 12, the line segment 16 connecting the bottom points a ′ to f ′ of the concave part, and the vertex of the convex part of the diffraction pattern 141 forming the triangular region 14. A line segment 17 that connects g to k and a line segment 18 that connects the bottom points g ′ to k ′ of the recesses can be regarded as substantially straight lines, but have different heights and depths. As a result, the diffraction grating pattern 12 constituting the cell and the diffraction pattern 141 forming the triangular region 14 emit different amounts of diffracted light. In addition, since the height and depth change abruptly at the boundary between the diffraction grating pattern 12 constituting the cell and the diffraction pattern 141 forming the triangular region 14, the contour is perceived clearly.

  When observing the OVD medium 30, the diffracted light of the diffraction grating pattern 12 constituting the cell is seen at a strong angle, but the diffracted light is emitted on the entire surface, but unlike the first embodiment, it does not depend on the cell structure. Since the amount of diffracted light is different by forming the triangle 14 pattern deeply, it is possible to make the triangle 14 pattern stand out even at a strong angle of the diffracted light. When the viewing angle is changed and the angle at which the diffracted light by the diffraction grating pattern 12 constituting the cell is weak, scattering of the surface of the OVD medium is caused by the difference in the height of the concavo-convex pattern protrusion and the depth of the concavo-convex pattern of the diffraction grating. Since the degree is different, the pattern of the triangle 14 can be clearly confirmed. By changing the pattern depending on the viewing angle, it is possible to easily determine the authenticity. Further, there is one area where the line segment connecting the apexes of the convex portions and / or the line segment connecting the bottom points of the concave portions is substantially linear, and one transition region where the height and / or depth of the concave-convex pattern gradually increases or decreases. By coexisting with the OVD medium, it is possible to display both an image with a clear outline and an image with an unclear outline, and the design is improved and the forgery prevention effect is further clarified.

  FIG. 9 is a plan view of an OVD medium 40 according to the fifth embodiment of the present invention. In this OVD medium 40, the diffraction grating pattern 12 constituting the cell 21 corresponding to the background and the hologram pattern 31 displaying the petals are composed of another uneven pattern 32 displaying stems and leaves independent of the cell structure.

  For example, the hologram pattern 31 is formed with an uneven height of 200 nm, and the diffraction grating pattern 12 constituting the cell is formed with a spatial frequency of 500 lines / mm and an uneven pattern depth of 200 nm. The diffraction grating pattern of the portion displaying the stem and leaves 32 is formed with a spatial frequency of 500 lines / mm and an uneven pattern depth of 100 nm. Due to the difference in height, the pattern (first image) of the stem and leaves 32 that can be confirmed by the difference in height between the diffraction grating pattern 12 corresponding to the background portion (first image), the flower displayed by the hologram pattern 31, and the height of the uneven pattern. 2 image) can be confirmed. The above effects can be exhibited even by changes in the depth of the concavo-convex pattern. Thus, it can also be set as the structure containing both a hologram pattern and a diffraction grating pattern.

  By pasting each OVD medium with anti-counterfeiting described above on information printed matter such as securities, cards, certificates, etc., it becomes impossible to forge the information printed matter using a copying machine, etc., and the OVD medium itself is extremely counterfeited. Since it is difficult, the information printed matter to which the OVD medium is attached has a high anti-counterfeit effect, and authenticity determination can be performed with certainty.

  When used for stickers, seals, etc., the thickness of the OVD medium is generally about 0.1 mm to 0.3 mm. By providing a large difference in height and / or depth of the concavo-convex pattern within this range, an image due to the difference in height can be clearly displayed. In addition, when used for printed information such as cards and paper, the OVD medium is about 10 μm to 0.2 mm, and the difference in height and / or depth of the concavo-convex pattern is within this range and is 10 nm or more. , An image due to the height difference can be recognized, and a sufficiently thin OVD medium can be provided.

1 is a plan view showing an example of an OVD medium according to a first embodiment of the present invention. FIG. 2 is a schematic sectional view taken along line X-X ′ in FIG. 1. The schematic sectional drawing which shows an example of the OVD medium which concerns on the 2nd Embodiment of this invention. The top view which shows an example of the OVD medium which concerns on the 3rd Embodiment of this invention. FIG. 5 is a schematic cross-sectional view of the boundary between the diffraction grating pattern 12 and the circle 13 in FIG. 4. 4 is an enlarged view of a part of the OVD medium shown in FIG. The top view of the OVD medium which concerns on the 4th Embodiment of this invention. Sectional drawing of the boundary of the diffraction grating pattern 12 of FIG. The plain view of the OVD medium which concerns on the 5th Embodiment of this invention. FIG. 3 is a schematic cross-sectional view showing an example of an OVD medium configuration. FIG. 3 is a schematic cross-sectional view showing an example of a general OVD medium configuration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Diffraction grating pattern of 1st image display area 12 ... Diffraction grating pattern of 1st image display area which comprises cell structure 13 ... 2nd image display area (circle)
131, 131′141... Diffraction grating pattern in second image display region 131′a... Constant pattern portion 131′b. Transition portion 14... Second image display region (triangle)
15 ... A straight line connecting the vertices of the convex portions of the diffraction grating pattern in the first image display area 16 ... A straight line connecting the bottom points of the concave parts of the diffraction grating pattern in the first image display area 17 ... Diffraction in the second image display area A straight line connecting the apexes of the convex portions of the lattice pattern 18... A straight line connecting the bottom points of the concave portions of the diffraction grating pattern in the second image display area 31. A hologram pattern displaying petals 32. Contour due to change in height and / or depth 23 ... base material 24 ... uneven pattern forming layer 25 ... metal deposition layer 26 ... adhesive layer 27 ... printed matter 28 ... height of uneven pattern 29 ... depth of uneven pattern

Claims (3)

A concavo-convex pattern having a pattern forming layer formed with a plurality of cells each having a uniform concavo-convex pattern for displaying a first image by interference and / or diffraction of light on the surface, and displaying the first image Oite the part of, consists uneven pattern having a height and / or depth different from the height and / or depth of the concavo-convex pattern, and the second image display area that does not depend on the cell structure is provided The concavo-convex pattern of the second image display area has a constant pattern portion in which a line segment connecting the apex of the convex part or the bottom point of the bottom part is a substantially straight line parallel to the pattern non-formation surface of the pattern forming layer, constant from pattern portion to the concavo-convex pattern to display the first image through to, characterized by having a height and / or increasing or decreasing the transition portion depth, the height, the The distance from the apex of the convex portion of the convex pattern to the pattern non-forming surface of the pattern forming layer, the depth is the distance from the apex of the convex portion of the concavo-convex pattern to the bottom point of the recess, OVD medium. The difference in height and / or depth between the uneven pattern in the first image display area and the uneven pattern in the fixed pattern portion in the second image display area is 10 nm or more and 0.3 mm or less. The OVD medium according to claim 1, wherein An information printed matter comprising the OVD medium according to claim 1 .

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