JP5347233B2 - Diffraction image display and labeled article - Google Patents

Description

  The present invention relates to a diffraction image display and an article with a label.

  Many of the diffraction image display bodies include a plurality of diffraction gratings having different display colors. The display color of the diffraction grating is a structural color that changes according to the illumination direction and / or the observation direction. That is, the diffraction grating causes a color shift. Such features cannot be reproduced with normal printing techniques. Therefore, the diffraction image display is mainly used for the purpose of preventing forgery of articles.

For this purpose, it is desirable that the image displayed by the diffraction image display body can be easily confirmed. In addition, the diffraction image display body needs to be difficult to read a display image by an optical image reader. If this reading is difficult, the display body obtained by copying the diffraction image display body displays an image significantly different from the diffraction image display body. As described in Patent Document 1, when displaying an image in which the diffraction image display body is significantly different from the display body obtained by copying, the display body obtained by copying the diffraction image display body is a copy. This can be easily understood. If it is difficult to read the display image, it is also difficult to forge the diffraction image display body using the read image.
JP-A-9-62411

  An object of the present invention is to make it possible to display a diffraction image that is easy to confirm the shape and difficult to read by an optical image reader.

According to a first aspect of the present invention, comprises a first and a second diffraction grating adjacent to each other, said first and second diffraction grating, the range of the array direction of case sagittal is 0.2 ° to 2 ° different from each other in the inner, and the difference spatial frequency of 7 lines / mm or less, can check the boundary between the front Symbol image wherein the image first diffraction grating displays second diffraction grating is displayed visually There is provided a diffractive image display, which is characterized by the following.

  According to the second aspect of the present invention, there is provided a labeled article comprising the diffraction image display according to the first aspect and an article supporting the diffraction image display.

  According to the present invention, it is possible to display a diffraction image that is easy to confirm the shape and difficult to read by an optical image reader.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same referential mark is attached | subjected to the component which exhibits the same or similar function, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a plan view schematically showing a diffraction image display according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II of the diffraction image display body shown in FIG.

  As shown in FIG. 2, the diffractive image display body 10 includes a base material 11, a diffraction grating forming layer 12, and a reflective layer 13.

  The base material 11 is a resin layer such as a resin film or a resin sheet, for example. As a material of this resin layer, for example, polyethylene terephthalate, polyethylene, polypropylene, heat resistant vinyl chloride, or polycarbonate can be used. The substrate 11 may have a single layer structure or a multilayer structure. The base material 11 can be omitted, for example, when the diffraction image display body 10 is used as a part of a transfer foil described later.

  The diffraction grating forming layer 12 is formed on the substrate 11. A concave structure and / or a convex structure is provided on the surface of the diffraction grating forming layer 12. The concave structure and / or the convex structure forms relief type diffraction gratings 12a and 12b. The images displayed by the diffraction gratings 12a and 12b will be described later.

  As a material of the diffraction grating formation layer 12, for example, a thermoplastic resin, a thermosetting resin, or a photocurable resin can be used. As the thermoplastic resin, for example, an acrylic resin, an epoxy resin, a cellulose resin, or a vinyl resin can be used. As a thermosetting resin, a urethane resin, a melamine resin, or a phenol resin can be used, for example. As the photocurable resin, for example, an epoxy acrylic resin, an epoxy methacrylic resin, a urethane acrylate resin, or a urethane methacrylate resin can be used. These resins may be used alone or in combination. The diffraction grating forming layer 12 may have a single layer structure or a multilayer structure.

  The diffraction grating forming layer 12 can be formed, for example, by transfer using a plate as described below.

  First, a master plate having a concave structure and / or a convex structure on the surface is manufactured. The master plate is manufactured by, for example, a method using optical photographing or a method using electron beam drawing.

  Next, a press plate is manufactured using the master plate manufactured by the method described above. The press plate is manufactured, for example, by forming a nickel layer on the surface of the master plate on which the concave structure and / or the convex structure are provided using an electroplating method.

Thereafter, the diffraction grating forming layer 12 is formed using this press plate.
When a thermoplastic resin is used as the material for the diffraction grating forming layer 12, first, a thermoplastic resin layer is formed on the substrate 11. Next, a press plate is pressed against the thermoplastic resin layer, and the thermoplastic resin layer is heated. Thereby, the concave structure and / or convex structure provided in the press plate are transferred to the thermoplastic resin layer. Thereafter, the press plate is removed from the thermoplastic resin layer. As described above, the diffraction grating forming layer 12 is obtained.

  When a thermosetting resin is used as the material of the diffraction grating forming layer 12, first, the substrate 11 and the press plate are overlapped with an uncured thermosetting resin layer interposed therebetween. Next, in this state, the thermosetting resin layer is heated and cured. Thereafter, the press plate is removed from the thermosetting resin layer. As described above, the diffraction grating forming layer 12 is obtained.

  When using a photocurable resin as the material of the diffraction grating forming layer 12, first, the substrate 11 and the press plate are overlapped with an uncured photocurable resin layer interposed therebetween. Next, in this state, the photocurable resin layer is irradiated with energy rays such as ultraviolet rays or electron beams to be cured. Thereafter, the press plate is removed from the photocurable resin layer. As described above, the diffraction grating forming layer 12 is obtained.

  The reflective layer 13 is formed on the diffraction grating forming layer 12. The reflective layer 13 is a layer having light reflectivity, and makes it easier to visually recognize the structural color expressed by the diffraction grating forming layer 12.

  As the reflective layer 13, for example, a metal reflective layer can be used. As a material of the metal reflective layer, for example, a metal such as aluminum, tin, chromium, nickel, copper and gold, or an alloy thereof can be used.

  In addition to light reflectivity, the reflective layer 13 may further have light transmissivity. As such a reflective layer 13, for example, a high refractive index layer having a larger refractive index than the portion of the diffraction grating forming layer 12 that is in contact with the reflective layer 13 can be used. As a material for the high refractive index layer, for example, zinc sulfide or titanium dioxide can be used.

  The reflective layer 13 may have a single layer structure or a multilayer structure. The reflective layer 13 can be formed by, for example, a vapor deposition method such as a vacuum evaporation method or a sputtering method.

  The reflective layer 13 may be omitted. Alternatively, the reflective layer 13 may be patterned. The patterned reflective layer 13 can be formed using, for example, etching or laser light irradiation.

  In the diffraction image display body 10, the diffraction gratings 12a and 12b formed on the diffraction grating forming layer 12 have different spatial frequencies of the grating lines and / or arrangement directions of the grating lines. When the diffraction image display 10 is observed with the naked eye, the image Ia displayed by the diffraction grating 12a and the image Ib displayed by the diffraction grating 12b appear as separate images. That is, the boundary between the image Ia and the image Ib can be confirmed visually. In the diffraction gratings 12a and 12b, the difference in the spatial frequency of the grating lines is 7 lines / mm or less, and the difference in the arrangement direction of the grating lines is within 2 °.

  The term “grating line” means a groove constituting the diffraction grating. Therefore, the spatial frequency of the lattice line is the reciprocal of the lattice constant (mm). Also, the arrangement direction of the lattice lines is a direction perpendicular to the lattice lines.

  When the difference in spatial frequency and the difference in arrangement direction are within the above ranges, the optical image reader reads the image Ia displayed by the diffraction grating 12a and the image Ib displayed by the diffraction grating 12b as separate images. Cannot be read as one image. That is, the boundary between the image Ia and the image Ib cannot be identified by an optical image reader.

  In this way, the diffraction gratings 12a and 12b display images Ia and Ib that appear as separate images when viewed with the naked eye and are read as one image by an optical image reader. Therefore, the diffraction image display body 10 is easy to determine authenticity by visual observation, for example, and difficult to counterfeit.

  The difference in the spatial frequency of the lattice lines is, for example, 1 / mm or more. Alternatively, the difference in the arrangement direction of the grid lines is, for example, 0.2 ° or more. This makes it easier to discriminate between the image Ia and the image Ib with the naked eye.

  In the diffraction image display 10 shown in FIGS. 1 and 2, the diffraction grating 12a and the diffraction grating 12b have different spatial frequencies and arrangement directions of the grating lines, but only one of the spatial frequency and the arrangement direction is different. Also good. For example, the diffraction grating 12a and the diffraction grating 12b may have the same spatial frequency of the grating lines and different arrangement directions of the grating lines. Alternatively, the diffraction grating 12a and the diffraction grating 12b may have different spatial frequencies of the grating lines so that the arrangement directions of the grating lines are equal.

  The diffraction image display body 10 may further include a diffraction grating that is different from the diffraction gratings 12a and 12b in at least one of the spatial frequency and the arrangement direction of the grating lines. In this case, the diffraction grating and the diffraction gratings 12a and 12b may or may not satisfy the above-described conditions regarding the spatial frequency and arrangement direction of the grating lines.

  It is advantageous that the image to be displayed on the diffraction image display 10 is composed of a plurality of pixels arranged two-dimensionally. This will be described below.

  FIG. 3 is a plan view schematically showing an example of a diffraction image display body having a pixel structure in which a plurality of pixels are arranged in a matrix.

  The diffraction image display body 10 has a pixel structure in which 12 pixels are arranged in a matrix. The pixel PXa has the same structure, and the pixel PXb has the same structure. The pixel PXa has the same structure as the portion corresponding to the diffraction grating 12a of the diffraction image display body 10 shown in FIGS. The pixel PXb has the same structure as the portion corresponding to the diffraction grating 12b of the diffraction image display body 10 shown in FIGS.

  As described above, in the diffraction image display body 10 shown in FIG. 3, two types of pixels PXa and PXb are arranged to form an image. If the visual effect of each of these pixels PXa and PXb is known, it is easy to predict the image obtained by rearranging them. Therefore, the structure to be adopted for each pixel can be easily determined from the digital image data. Therefore, when the pixel structure is adopted for the diffraction image display body 10, the design of the diffraction image display body 10 becomes easy.

  Note that the diffraction image display 10 shown in FIG. 3 employs a pixel structure in which two types of pixels are arranged in a matrix, but a pixel structure in which three or more types of pixels are arranged in a matrix. May be adopted. If the number of types of pixels is increased, a more complicated image can be displayed.

  The diffractive image display 10 shown in FIG. 3 employs an image structure in which 12 pixels are arranged in a matrix, but the number of pixels included in the pixel structure may be two or more. However, when the number of pixels is increased, a higher-definition image can be displayed.

  The diffraction image display body 10 described with reference to FIGS. 1 to 3 can be used in various forms. Here, the use of the diffraction image display body 10 will be described by taking the diffraction image display body 10 shown in FIGS. 1 and 2 as an example.

  FIG. 4 is a cross-sectional view schematically showing an example of an adhesive label including the diffraction image display body shown in FIGS. 1 and 2. The adhesive label 20 includes a diffraction image display body 10 and an adhesive layer 21 provided on the back surface thereof. The adhesive label 20 is attached to, for example, an article to be confirmed as an authentic product, or attached to another article such as a tag to be attached to such an article. In this way, for example, by observing the image displayed by the diffraction image display 10, it can be confirmed that the article is genuine.

  The adhesive label 20 may be brittle. Such an adhesive label 20 is obtained, for example, by forming notches and / or perforations in the diffraction image display body 10. When the pressure-sensitive adhesive label 20 is brittle, for example, when the pressure-sensitive adhesive label 20 attached to an article to be confirmed to be genuine is peeled off, the diffraction image display body 10 is easily destroyed. Therefore, it becomes difficult to replace the adhesive label 20.

  The adhesive label 20 may be supported on release paper. That is, the adhesive layer 21 may be covered with release paper. This facilitates handling of the adhesive label 20.

  FIG. 5 is a cross-sectional view schematically showing an example of a transfer foil including the diffraction image display body shown in FIGS. 1 and 2. The transfer foil 30 includes a base material 31, a peel protection layer 32, the diffraction image display body 10, and an adhesive layer 33. The diffraction image display 10 does not include the base material 11 shown in FIG. 2 but includes a diffraction grating forming layer 12 and a reflective layer 13.

  The base material 31 serves as a base for forming the peeling protection layer 32, the diffraction image display body 10, and the adhesive layer 33. As the material of the base material 31, for example, the materials exemplified for the base material 11 shown in FIG. 2 can be used.

  The peeling protective layer 32 is interposed between the base material 31 and the diffraction grating forming layer 12. The peeling protective layer 32 plays a role of preventing the diffraction grating forming layer 12 from being damaged when the substrate 31 is peeled from the diffraction image display body 10. Examples of the material of the peeling protection layer 32 include thermoplastic resins such as chlorinated rubber resins, vinyl chloride, vinyl acetate copolymers, acrylic resins, cellulose resins, styrene resins, and chlorinated polypropylene resins, or the like. A paint containing a mixture obtained by adding a release aid such as silicone oil can be used.

  When this transfer foil 30 is used, for example, it is affixed to an article to be confirmed as an authentic product, or affixed to another article such as a tag to be attached to such an article, and then a diffraction image. The base material 31 is peeled from the display body 10. Thereby, the diffraction image display body 10 is supported by the previous article. In this way, for example, by observing the image displayed by the diffraction image display 10, it can be confirmed that the article is genuine.

  The adhesive layer 33 may be covered with release paper. This facilitates handling of the transfer foil 30.

  FIG. 6 is a cross-sectional view schematically showing an example of a recording medium including the diffraction image display shown in FIGS. The recording medium 40 includes paper 41 and a diffraction image display body 10 embedded therein. An opening is provided in a portion of the paper 41 that covers the front surface of the diffraction image display 10. Thereby, the visibility of the image which the diffraction image display body 10 displays is improved. Note that the opening of the paper 41 does not have to be provided as long as this image is visible.

  The recording medium 40 can be used as a sheet for an authentication medium such as a cash card, a credit card and a passport, or a securities medium such as a gift certificate and a stock certificate, for example. Alternatively, the recording medium 40 can be used as a part of an adhesive label described later. Alternatively, the recording medium 40 can be used as a tag to be attached to an article to be confirmed to be genuine or a part thereof. Alternatively, the recording medium 40 can be used as a package or a part thereof that contains an article to be confirmed to be genuine.

  The recording medium 40 is obtained, for example, by sandwiching the diffraction image display body 10 between fiber layers during papermaking. The recording medium 40 obtained by such a method is difficult to forge.

  FIG. 7 is a cross-sectional view schematically showing an example of an adhesive label including the recording medium of FIG. The adhesive label 50 includes a recording medium 40 and an adhesive layer 51 provided on the back surface thereof. The adhesive label 50 is attached to, for example, an article to be confirmed as an authentic product, or attached to another article such as a tag base material to be attached to such an article.

  FIG. 8 is a plan view schematically showing an example of a labeled article including the diffraction image display shown in FIGS. 1 and 2. The labeled article 100 includes an article 101 and a diffraction image display body 10.

  The article 101 is an article to be confirmed to be a genuine product. The article 101 is, for example, an authentication medium such as a cash card, a credit card, and a passport, or a securities medium such as a gift certificate and a stock certificate. The article 101 may be an article other than the authentication medium and the securities medium. For example, the article 101 may be a craft or a work of art. Alternatively, the article 101 may be a packaged product including a package and contents contained therein.

  The diffraction image display body 10 is supported by the article 101. For example, the diffraction image display body 10 is attached to the article 101. In this case, for example, by attaching the adhesive label 20 shown in FIG. 4 or the adhesive label 50 shown in FIG. 7 to the article 101 or using the transfer foil 30 shown in FIG. Can be made.

The diffraction image display 10 may be supported on the article 101 by other methods.
For example, when the article 101 includes paper, the diffraction image display body 10 may be embedded in the paper. In this case, the labeled article 100 is obtained, for example, by sandwiching the diffractive image display body 10 between fiber layers during papermaking and then performing printing or the like on a paper surface as necessary. In order to facilitate visualization of the latent image, an opening may be provided in a portion of the paper covering the front surface of the diffraction image display body 10. Moreover, there is no restriction | limiting in particular in the shape of the diffraction image display body 10 embedded in paper. For example, the thread-like diffraction image display 10 may be embedded in paper.

  The diffraction image display body 10 may be supported by the article 101 by attaching a tag including the diffraction image display body 10 to the article 101. If it is difficult for a general user to replace the tag on the article 101, the diffraction image display 10 is sufficiently useful for confirming the authenticity of the article 101.

Examples of the present invention will be described below.
(Example 1)
In this example, a plurality of diffraction image display bodies 10 shown in FIGS. 1 and 2 are manufactured, the relationship between the structure of the diffraction gratings 12a and 12b and the image read by the optical image reader, and the structure of the diffraction gratings 12a and 12b. And the relationship between the image visibility and the image visibility.

Specifically, a plurality of diffraction image display bodies 10 having different spatial frequencies of the grating lines constituting the diffraction grating 12b and / or angles formed by the grating lines of the diffraction grating 12b with respect to the grating lines of the diffraction grating 12a are manufactured. did. In each diffraction image display 10, the spatial frequency of the grating lines constituting the diffraction grating 12a was set to 1000 lines / mm. Then, an image displayed by each diffraction image display 10 was read by an optical image reader, and it was examined whether the image reader would read the images Ia and Ib as separate images or as one image. Moreover, each diffraction image display body 10 was observed with the naked eye while illuminating with white light, and it was examined whether the images Ia and Ib were seen as separate images or as one image. The results are summarized in the following table.

  In the table, “◯” marks indicate that the images Ia and Ib were seen as separate images when the image reader read the images Ia and Ib as one image and observed with the naked eye. The “x” mark indicates that when the image reader reads the images Ia and Ib as separate images and observes them with the naked eye, the images Ia and Ib appear as separate images. The “Δ” mark indicates that the images Ia and Ib are seen as one image when the image reader reads the images Ia and Ib as one image and observes them with the naked eye.

As shown in the above table, when the difference between the spatial frequency of the grating line constituting the diffraction grating 12b and the spatial frequency of the grating line constituting the diffraction grating 12a is increased, the image Ia is observed when observed with the naked eye. However, the image reader can read the images Ia and Ib as separate images. Further, when the angle formed by the grating lines constituting the diffraction grating 12b with respect to the grating lines constituting the diffraction grating 12a is increased, the images Ia and Ib can be easily distinguished when observed with the naked eye. The image reader can read the images Ia and Ib as separate images.
The invention described in the original claims is appended below.
[1] The first and second diffraction gratings are adjacent to each other, and the first and second diffraction gratings have different spatial frequencies of the grating lines and / or arrangement directions of the grating lines, and the difference between the spatial frequencies. Is 7 lines / mm or less, the difference in the arrangement direction is within 2 °, and the boundary between the image displayed by the first diffraction grating and the image displayed by the second diffraction grating can be visually confirmed. A diffraction image display, characterized in that:
[2] It has a pixel structure in which a plurality of pixels are arranged in a matrix, and the plurality of pixels includes a first pixel including the first diffraction grating, a second diffraction grating, and the first. Item 2. The diffraction image display body according to Item 1, comprising a second pixel adjacent to the pixel.
[3] A labeled article comprising the diffraction image display according to Item 1 or 2 and an article supporting the diffraction image display.

The top view which shows roughly the diffraction image display body which concerns on 1 aspect of this invention. Sectional drawing along the II-II line of the diffraction image display body shown in FIG. The top view which shows roughly an example of the diffraction image display body which has the pixel structure which arranges a some pixel in matrix form. Sectional drawing which shows schematically an example of the adhesive label containing the diffraction image display body shown in FIG.1 and FIG.2. Sectional drawing which shows roughly an example of the transfer foil containing the diffraction image display body shown in FIG.1 and FIG.2. FIG. 3 is a cross-sectional view schematically illustrating an example of a recording medium including the diffraction image display body illustrated in FIGS. 1 and 2. Sectional drawing which shows schematically an example of the adhesive label containing the recording medium of FIG. The top view which shows roughly an example of the labeled article containing the diffraction image display body shown in FIG.1 and FIG.2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Diffraction image display body, 11 ... Base material, 12 ... Diffraction grating formation layer, 12a ... Diffraction grating, 12b ... Diffraction grating, 13 ... Reflection layer, 20 ... Adhesive label, 21 ... Adhesive layer, 30 ... Transfer foil, 31 DESCRIPTION OF SYMBOLS ... Base material, 32 ... Release protective layer, 33 ... Adhesive layer, 40 ... Recording medium, 41 ... Paper, 50 ... Adhesive label, 51 ... Adhesive layer, 100 ... Article with label, 101 ... Article.

Claims (3)

Comprises a first and a second diffraction grating adjacent to each other, said first and second diffraction grating are different from each other within the array direction 0.2 ° to 2 ° of case sagittal, the spatial frequency the difference is not more than seven / mm, before Symbol diffraction image display, which is a possible check visually the boundaries between the image which the image of the first diffraction grating displays second diffraction grating is displayed body.   A plurality of pixels arranged in a matrix, the plurality of pixels including a first pixel including the first diffraction grating, a second diffraction grating, and adjacent to the first pixel; The diffraction image display body according to claim 1, further comprising a matched second pixel.   A labeled article comprising the diffraction image display body according to claim 1 and an article supporting the diffraction image display article.

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