JP2009198549A - Display body and article with label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display body capable of achieving high effect of forgery prevention. <P>SOLUTION: This display body is constituted in such a way that a main face on one side of a relief structure forming layer includes at least a low reflection boundary face part where a plurality of recessed and projecting parts are arranged with an inter-center distance of less than the shortest wavelength of visible light and the low reflection boundary face part forms a minute concealed image. The minute concealed image is a microcharacter composed of character or symbol or numeral or a combination of them, and the length of one side of the minute concealed image is 1 μm or more and 300 μm or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display technique that provides, for example, an anti-counterfeit effect.

  Generally, securities such as gift certificates and checks, cards such as credit cards, cash cards and ID cards, and certificates such as passports and licenses must be printed with ordinary printed materials to prevent counterfeiting. Is attached with a display that exhibits different optical effects. In recent years, the distribution of counterfeit goods has become a social problem for articles other than these. Therefore, the opportunity to apply the same forgery prevention technology to such articles is increasing.

  As a display body that exhibits an optical action different from that of a normal printed matter, a display body including a diffraction grating in which a plurality of grooves are arranged is known. For example, the display body can display an image that changes according to the observation conditions, can display a stereoscopic image, and can also obtain a display image such as a full-color photograph. Further, the spectral color shining in rainbow colors displayed by the diffraction grating cannot be expressed by a normal printing technique. Therefore, a display body including a diffraction grating is widely used for articles that require anti-counterfeiting measures.

  In this display, a relief type diffraction grating is generally used. The relief type diffraction grating is usually obtained by duplicating from an original plate manufactured using photolithography. For example, in Patent Documents 1 and 2, in order to form a diffraction grating, a flat substrate coated with a photosensitive resist on one main surface is placed on an XY stage, and the stage is controlled under computer control. It is described that the photosensitive resist is subjected to pattern exposure by irradiating the photosensitive resist with an electron beam while being moved. Non-Patent Document 1 describes that a diffraction grating is formed using two-beam interference.

  However, since the relief type diffraction grating used for this display body can be formed relatively easily if there is an apparatus such as an exposure apparatus, the forgery prevention effect of this display body is decreasing.

  Therefore, in the display body used for anti-counterfeiting purposes, in order to further improve the anti-counterfeiting effect, a minute character or the like that is generally called a micro character and is difficult or impossible to visually recognize is part of the display body. To be formed. Micro characters can be imparted without impairing the design of the entire display body, and since the structure is minute, higher processing techniques are required.

  The size of the micro characters is from about 300 μm to 1000 μm, which is barely recognizable with the naked eye, so that the user of the printed matter on which the display body is affixed can judge the authenticity. It is assumed that authenticity determination is performed by magnified observation with a microscope or the like and has a size of 300 μm or less that cannot be recognized with the naked eye.

  As the structure of the micro character, there are a structure in which the height of the structure is different between the inside and the outside of the character, and a structure in which a relief type diffraction grating is formed inside the character (see Patent Document 3).

  The ones that differ only in the height of the structure inside and outside the character are relatively easy to process, and almost no optical action occurs, so the concealment effect when viewed with the naked eye is high. Even when magnified, the boundary between the inside and the outside of the character is not clear, so that it may be difficult to read the character information, or it may be difficult to determine authenticity.

  On the other hand, micro characters composed of diffraction gratings have a higher anti-counterfeiting effect because higher processing accuracy is required, but diffracted light shines when observed with the naked eye, resulting in a special structure at that location. It is easy to recognize that it is formed, and a sufficient concealing effect cannot be obtained. Further, the diffracted light from the micro characters may damage the design of the entire display body.

In addition, as a result of the use of display bodies including micro characters in many articles requiring anti-counterfeiting measures, this technology is widely recognized, and accordingly, the generation of counterfeit products tends to increase. Therefore, it has become difficult to achieve a sufficient anti-counterfeit effect with such a display.
JP-A-2-72320 US Pat. No. 5,058,992 JP 2007-309960 A Junpei Takiuchi, "Holography", Maruzen Co., Ltd.

  The objective of this invention is providing the display body which exhibits the higher forgery prevention effect.

  According to the first aspect of the present invention, the main surface of the relief structure forming layer includes at least a low-reflectivity interface portion in which a plurality of convex portions or concave portions are arranged at a center-to-center distance less than the shortest wavelength of visible light. The display body is characterized in that the low-reflective interface portion forms a fine concealment image.

  According to the 2nd side surface of this invention, the labeled article provided with the display body of any one of Claims 1 thru | or 8, and the article | item which supported this is provided.

  According to the present invention, by forming a micro concealment image such as micro characters with a low-reflective interface having a light reflection preventing function, the concealment effect of the micro concealment image is high when the display body is observed with the naked eye, When magnifying and observing with a magnifying glass or an optical microscope, the contrast between the inside and outside of the minute concealment image is clearly separated, so that the authenticity determination can be performed reliably. Thereby, the forgery prevention effect of a display body can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that, throughout all the drawings, the same reference numerals are given to components that exhibit the same or similar functions, and redundant descriptions are omitted.

  FIG. 1 is a plan view schematically showing a display body according to one aspect of the present invention. 2 is a cross-sectional view taken along the line II-II of the display shown in FIG. This display body 10 includes a laminate of a relief structure forming layer 11 and a reflective layer 13. In the example shown in FIG. 2, the relief structure forming layer 11 side is the front side and the reflective layer 13 side is the back side. Yes. The interface between the relief structure forming layer 11 and the reflective layer 13 includes a plurality of interface parts (a first interface part IF1, a second interface part IF2, and a third interface part IF3), and the first interface part IF1 includes a plurality of interface parts. Is a low-reflective interface portion in which the concave portions or convex portions are arranged at a center-to-center distance less than the shortest wavelength of visible light, and form a minute concealment image. Hereinafter, portions of the display body 10 corresponding to the first interface portion IF1 to the third interface portion IF3 are referred to as first display portion DA1 to third display portion DA3, respectively.

  The relief structure forming layer 11 used in the present invention has a low reflective interface portion (first interface portion) in which a plurality of convex portions or concave portions are arranged on one main surface at a center-to-center distance less than the shortest wavelength of visible light. As a material of the relief structure forming layer 11, for example, a resin having optical transparency such as polycarbonate and polyester can be used. For example, when a thermoplastic resin or a photocurable resin is used, the relief structure forming layer 11 having a convex portion or a concave portion provided on one main surface can be easily formed by transfer using the original plate.

  In FIG. 2, as an example, the relief structure forming layer 11 configured by a laminate of the light transmissive substrate 111 and the light transmissive resin layer 112 is depicted. The light transmissive substrate 111 is a film or sheet that can be handled by itself. The light transmissive resin layer 112 is a layer formed on the light transmissive substrate 111. The relief structure forming layer 11 shown in FIG. 2 is obtained, for example, by applying a thermoplastic resin or a photocurable resin on the light transmissive substrate 111 and curing the resin while pressing the original plate against the coating film. Can do.

  Next, the low reflective interface portion (first interface portion IF1) in which a plurality of convex portions or concave portions are arranged at a center-to-center distance less than the shortest wavelength of visible light will be described.

  FIG. 3 is a perspective view showing an example of a structure that can be employed in the low-reflectivity interface portion (first interface portion IF1) of the display body 10 shown in FIGS. The first interface part IF1 in FIG. 3 represents a low reflection interface part in which convex parts or concave parts are arranged in a lattice pattern. FIG. 4 is a plan view of the structure shown in FIG. In FIG. 3, a low-reflectivity interface portion (first interface portion IF1) viewed from the relief structure forming layer 11 side is depicted.

  The low-reflectivity interface part (first interface part IF1) shown in FIG. 3 is provided with a plurality of convex parts PR arranged at a center-to-center distance less than the shortest wavelength of visible light. The center-to-center distance here means the distance between the convex parts PR arranged adjacent to each other. In the example shown in FIG. 3, the protrusions PR are arranged in a lattice pattern in the x direction and the y direction substantially orthogonal to each other, but the protrusions PR are arranged in a lattice pattern that intersects in a different direction. In addition, the lattice-like arrangement may be curved or meandering.

  In the low reflective interface part (first interface part IF1) shown in FIG. 3, the convex part PR forms a so-called diffraction grating. The diffraction grating formed by the convex part PR functions in substantially the same manner as a diffraction grating in which grooves (that is, grating lines) are arranged as indicated by broken lines (see FIG. 4).

  Next, the visual effect which the low reflective interface part (1st interface part IF1) shown in FIG.3 and FIG.4 has is demonstrated.

  When illumination light is irradiated onto the diffraction grating using an illumination light source, the diffraction grating emits strong diffracted light in a specific direction with respect to the traveling direction of the illumination light that is incident light.

The emission angle β of m-order diffracted light (m = 0, ± 1, ± 2,...) can be calculated from the following equation when light travels in a plane perpendicular to the grating line of the diffraction grating. .
d = mλ / (sin α−sin β)
In this equation, d represents the grating constant of the diffraction grating, m represents the diffraction order, and λ represents the wavelengths of incident light and diffracted light. Α represents the exit angle of 0th-order diffracted light, that is, transmitted light or specularly reflected light. In other words, the absolute value of α is equal to the incident angle of the illumination light, and in the case of a reflective diffraction grating, the incident direction of the illumination light and the emission direction of the regular reflection light are the method of the interface where the diffraction grating is provided. Symmetric with respect to the line.

  When the diffraction grating is a reflection type, the angle α is 0 ° or more and less than 90 °. In addition, when illumination light is irradiated to the interface provided with the diffraction grating from an oblique direction, and the angle in the normal direction, that is, two angle ranges having a boundary value of 0 °, the angle β is determined as follows. A positive value is obtained when the exit direction and the exit direction of the specularly reflected light are within the same angular range, and a negative value when the exit direction of the diffracted light and the incident direction of the illumination light are within the same angular range. Hereinafter, an angle range including the emission direction of the specularly reflected light is referred to as a “positive angle range”, and an angle range including the incident direction of the illumination light is referred to as a “negative angle range”.

  When the diffraction grating is observed from the normal direction, the diffracted light contributing to the display is only diffracted light having an exit angle β of 0 °.

  Therefore, when the lattice constant d is larger than the wavelength λ, there exists a wavelength λ and an incident angle α that satisfy the above equation. That is, in this case, the observer can observe diffracted light having a wavelength λ that satisfies the above equation.

  On the other hand, when the lattice constant d is smaller than the wavelength λ, there is no incident angle α that satisfies the above equation. Therefore, in this case, the observer cannot observe the diffracted light.

  As is clear from this explanation, the low-reflectivity interface portion (first interface portion IF1) whose lattice constant d (intercenter distance) is less than the shortest wavelength of visible light does not emit diffracted light in the normal direction. Therefore, when observed from the normal direction, the first display unit DA1 does not display the spectral color due to diffraction. That is, the first display portion DA1 is visually recognized as a dark gray or black print layer.

  A so-called normal diffraction grating that has a grating constant d (distance between centers) equal to or greater than the shortest wavelength of visible light and diffracts visible light, and low reflection that has a lattice constant d (distance between centers) that is less than the shortest wavelength of visible light. It differs from the diffraction grating provided in the interface (first interface IF1) in the following points.

  FIG. 5 is a diagram schematically showing how a normal diffraction grating emits first-order diffracted light. FIG. 6 is a diagram schematically showing a state in which the diffraction grating provided at the low reflective interface portion (first interface portion IF1) emits the first-order diffracted light. 5 and 6, IF indicates an interface on which a diffraction grating is formed, NL indicates a normal line of the interface IF, IL indicates illumination light, RL indicates specular reflection light or zero-order diffracted light, and DL indicates 1st order diffracted light is shown.

  As is clear from the above equation, when the grating constant d of the diffraction grating is larger than the shortest wavelength of visible light, when the illumination light IL is irradiated from an oblique direction with respect to the interface IF, the diffraction grating becomes as shown in FIG. As shown, the first-order diffracted light DL is emitted at an emission angle β within a positive angle range. In the present invention, the shortest wavelength of visible light represents a wavelength of 400 nm.

  On the other hand, when the grating constant d of the diffraction grating is less than the shortest wavelength of visible light, that is, less than 400 nm, when the illumination light IL is irradiated from an oblique direction to the interface IF, the diffraction grating becomes as shown in FIG. As shown, the first-order diffracted light DL is emitted at an emission angle β within a negative angle range. For example, considering the case where the angle α is 80 ° and the grating constant d is 300 nm, the diffraction grating emits first-order diffracted light having a wavelength λ of 540 nm at an emission angle β of about −25 °.

  In general, when observing an article, particularly when observing a light-absorbing article having a small light reflection ability and light scattering ability, the article and the light source are relative to the observer's eye so that regular reflection light can be perceived. Align. Therefore, when the configuration described with reference to FIG. 5 is used, the observer perceives diffracted light with a relatively high probability even if the observer does not know the fact itself. On the other hand, when the configuration described with reference to FIG. 6 is used, an observer who does not know the situation cannot perceive diffracted light in many cases. Therefore, it is difficult for the display 10 to realize that the first display unit DA1 can display diffracted light.

  Next, FIG. 7 shows a structure that can be employed in the low-reflectivity interface part (first interface part IF1) of the display body shown in FIGS. 1 and 2, and unlike the structure of FIG. Or it is a perspective view showing the interface part by which a recessed part is arrange | positioned at non-lattice form. Here, the arrangement of the plurality of convex portions or concave portions in a non-lattice manner means a state where the convex portions or the concave portions are irregularly arranged without a periodic arrangement rule. FIG. 8 is a plan view of the structure shown in FIG. In FIG. 7, a low-reflectivity interface portion (first interface portion IF1) viewed from the relief structure forming layer 11 side is depicted.

  As shown in FIG. 7, the low-reflectivity interface part (first interface part IF1) is provided with a plurality of convex parts PR arranged in a non-lattice shape, and the distance between the centers of the convex parts PR is visible light. It arrange | positions so that it may become less than the shortest wavelength. The center-to-center distance here means an average value of the distances between the convex parts PR arranged adjacent to each other in the first interface part IF1. The first display portion DA1 including the low-reflectivity interface portion (first interface portion IF1) configured by the irregularly arranged convex portions PR is the low-reflectivity interface portion (first surface) shown in FIG. Unlike the first display part DA1 composed of the interface part IF1), the first-order diffracted light DL is not easily observed. For example, even when the display body 10 is observed from an oblique direction, the first display part DA1 is dark gray or It is visually recognized as a black print layer.

  The structure that can be used for the low-reflectivity interface part (first interface part IF1) shown in FIG. 7 has a center-to-center distance less than the shortest wavelength of visible light (less than 400 nm), so that it looks like a dark gray or black print layer. Can be obtained.

  In the present invention, it is preferable that the distance between the centers of the convex portions or the concave portions formed in the low reflective interface portion (first interface portion IF1) is 200 nm or more and less than 400 nm. The convex portions or concave portions formed in the low reflective interface portion (first interface portion IF1) are arranged at a center-to-center distance less than the shortest wavelength (400 nm) of visible light for black display. If the distance is less than 200 nm, it becomes difficult to process or replicate. By setting an arbitrary value between 200 nm and less than 400 nm as the center-to-center distance, a sufficiently black or dark gray display becomes possible.

  As the shape of the plurality of convex portions or concave portions used in the low reflective interface portion (first interface portion IF1) of the present invention, a tapered shape can be used as shown in FIGS. It is not limited to. Examples of the tapered shape include a semi-spindle shape, a cone shape such as a cone and a pyramid, or a truncated cone shape such as a truncated cone and a truncated pyramid. Moreover, as a side surface shape of the some convex part or recessed part formed in a low reflective interface part (1st interface part IF1), it may be comprised only in the inclined surface and step shape may be sufficient.

  The taper shape has an effect of facilitating removal of the relief structure forming layer 11 from the original plate and improving productivity.

  When such a structure is adopted, if the distance between the centers of the convex parts PR is shorter than the shortest wavelength of visible light, the low reflective interface part (first interface part IF1) region has a thickness of the display body 10. It can be considered that it has a refractive index continuously changing in the vertical direction. For this reason, the reflectance of the regular reflection light at the low-reflectivity interface portion (first interface portion IF1) is small no matter what angle is observed. Further, even when a lattice-like low-reflectivity interface portion (first interface portion IF1) in which a plurality of convex portions or concave portions as shown in FIG. Little diffracted light is emitted.

  Therefore, for example, when the display body 10 is observed from the normal direction, the display unit DA1 looks dark. Typically, the display part DA1 looks dark gray or black. Here, “dark gray” means, for example, all wavelengths having a wavelength in the range of 400 nm to 700 nm when the display 10 is irradiated with light from the normal direction and the intensity of specular reflection light is measured. It means that the reflectance of the light component is about 25% or less. “Black” means, for example, the reflectivity of all light components having a wavelength in the range of 400 nm to 700 nm when the display 10 is irradiated with light from the normal direction and the intensity of specular reflection light is measured. Means 10% or less. Therefore, the display unit DA1 looks like a dark gray or black print layer, for example.

  In the low-reflectivity interface portion (first interface portion IF1) in the present invention, as the distance between the centers of the plurality of convex portions or concave portions becomes smaller, the brightness and saturation are lowered, and a black display is possible. As the distance increases, the luminance increases slightly and the structure is perceived as dark gray.

  In the low-reflectivity interface portion (first interface portion IF1) in the present invention, the larger the height or depth of the plurality of convex portions or concave portions, the more black display becomes possible, and the height and depth become smaller. As a result, the brightness rises and it becomes perceived as dark gray. Typically, it is desirable that the height be 1/2 or more of the center-to-center distance. Specifically, for example, when the center-to-center distance is 380 nm, dark gray can be displayed by setting the height or depth to 190 nm or more, and black display can be performed by setting the height to 380 nm or more. Become. If the structure is much higher than the center-to-center distance, sufficient blackness can be obtained and a highly accurate manufacturing technique is required, so that the forgery prevention effect can be further improved. Here, the height of the convex part or the concave part in the present invention means a height difference from the top part to the bottom part of the convex part or the concave part.

  In the first interface portion in the present invention, the degree of blackness to be observed changes by changing the shape of the plurality of convex portions or concave portions to be formed, and / or the distance between the centers, and / or the height. When the display body in the present invention includes two or more low-reflective interface portions, the shape of a plurality of convex portions or concave portions in the two or more low-reflective interface portions, and / or the center-to-center distance, or / and high By making them different from each other, it is possible to display images with different degrees of blackness when observed. That is, it is possible to perform display in which gradation is controlled stepwise from dark gray to black using a plurality of low-reflective interface portions.

  Next, the second interface part IF2 and the third interface part IF3 shown in FIG. 2 will be described.

  The second interface part IF2 and the third interface part IF3 are, for example, a diffraction grating formation surface or a light scattering structure formation surface, and may be flat surfaces. A plurality of second interface portions IF2 and third interface portions IF3 are provided on the display body 10, and a diffraction grating forming surface, a light scattering structure forming surface, a flat surface, and the like are provided on each of them, so that images can be used as image components. Form. By providing a diffraction grating formation surface at the second interface portion IF2 or the third interface portion IF3, an optical effect that shines in rainbow colors can be obtained by spectroscopy by the diffraction grating, and when a light scattering structure formation surface is provided The white or cloudy color can be displayed by the light scattering effect. In the case of a flat surface, a special optical effect cannot be obtained, but an image can be formed by a difference from other interface portions having other optical effects.

  FIG. 9 is a plan view schematically showing a display body according to one aspect of the present invention. FIG. 10 is an enlarged plan view of a region L surrounded by a dotted line of the display body shown in FIG. FIG. 11 is a plan view schematically showing a state in which a micro concealment image provided on a part of the display body shown in FIG. 10 is enlarged and observed with an optical microscope. 12 is a cross-sectional view of the display body shown in FIG. 11 taken along the broken line IV-IV.

  The display body 10 shown in FIGS. 9 to 12 includes a laminated body of a relief structure forming layer 11 and a reflective layer 13, and in the example shown in FIG. 12, the relief structure forming layer 11 side is the front side and the reflective layer is formed. The 13th side is the back side. The interface between the relief structure forming layer 11 and the reflective layer 13 includes a plurality of interface parts (fourth interface part IF4, fifth interface part IF5, and sixth interface part IF6), and the fourth interface part IF4 includes a plurality of interface parts. The concave portion or the convex portion is a low reflective interface portion arranged at a center-to-center distance less than the shortest wavelength of visible light, and forms a minute concealment image 01. Hereinafter, portions of the display body 10 corresponding to the fourth interface portion IF4 to the sixth interface portion IF6 are referred to as fourth display portion DA4 to sixth display portion DA6, respectively.

  As shown in FIGS. 9 and 10, by observing the display body 10 in an enlarged manner, the “horizontal line” portion of the display body 10 (display portion DA4 shown in FIG. 9) is formed by the micro characters “security”. (4th interface part IF4 shown in FIG.10 and FIG.11). The micro concealment image 01 is perceived as black or dark gray because it consists of a low-reflectivity interface portion (fourth interface portion IF4) having a light reflection preventing function.

  As the micro concealment image 10 in the present invention, it is preferable to use micro characters because it can be handled as common information regardless of the observer when authenticity determination is performed. The micro character is composed of a character, a symbol, a number, or a combination thereof, and represents a micro character string that makes sense by using a plurality of characters such as “security” in FIG.

  9 to 12, the fifth interface IF5 is a diffraction grating forming surface having a function of emitting diffracted light, and the sixth interface IF6 is a light scattering structure forming layer having a light scattering function. Accordingly, the fifth display unit DA5 has a function of emitting diffracted light, so that it appears to shine in iridescent colors according to the observation direction and the direction of the light source, and the sixth display unit DA6 has white or Looks cloudy.

  In the display body 10 shown in FIGS. 9 to 12, the fourth display portion DA4 (corresponding to the low-reflectivity interface portion), which is the minute concealment image 01 that does not emit light by the antireflection function, is the fifth brightly shining periphery. By being embedded in the display unit DA5 or the sixth display unit DA6 that emits white scattered light, recognition with the naked eye becomes difficult. In order to increase the concealment effect when observed with the naked eye, the size of the micro characters (micro concealment image 01) shown in FIGS. 10 and 11 is preferably smaller. Since it is difficult to manufacture a finer micro character with high accuracy, a higher anti-counterfeiting effect can be expected in terms of manufacturing technology.

  In addition, a micro character (small concealment image 01) having a size that is difficult or impossible to visually recognize with the naked eye is subjected to authenticity determination using an instrument or apparatus capable of magnifying observation such as a loupe or an optical microscope.

  12 is a cross-sectional view taken along line IV-IV in FIG. A reflective layer 13 made of metal is provided on the surface of the relief structure forming layer 11. Thus, when magnified, the fifth interface portion IF5 and the sixth interface portion IF6 perceive a metallic luster color such as gold or silver, while the fourth interface portion IF4 that is the micro concealment image 01 is black or dark. Looks gray. That is, since each color looks different, the micro concealment image 01 looks clear when enlarged and observed, and authenticity determination can be performed reliably.

  FIG. 13 shows the seventh interface IF7 in which the micro concealment image 01 is formed with a simple uneven structure, the eighth interface IF8 in which a diffraction grating is formed, and the ninth interface IF9 having a light scattering structure. It is a top view which shows notionally a mode that a part of display body of the conventional structure which becomes this was expanded and observed with the optical microscope. FIG. 14 is a cross-sectional view taken along line VV in FIG. 13, and the reflective layer 13 is provided on the surface of the relief structure forming layer 11. When the diffraction grating and the light scattering structure are observed at a high magnification with an optical microscope or the like, the scattering effect of the diffracted light and light cannot be perceived, and the structures are observed as they are as shown in FIG. Since the micro concealment image 01, diffraction grating, and light scattering structure formed with a simple concavo-convex structure do not have a light reflection preventing function, a metallic luster color such as gold or silver is perceived in any case. . For this reason, since the minute concealment image 01 and its peripheral part are perceived in the same color, the minute concealment image cannot be clearly observed.

  In other words, by forming the micro concealment image 01 with a low-reflective interface having a light reflection preventing function, the authenticity determination can be performed more surely, which is effective in improving the forgery prevention effect of the display body. It becomes.

  Note that, as the above-described example, the minute concealment image is configured by the first interface portion IF1 or the fourth interface portion IF4, and the peripheral portion thereof is configured by the interface portions IF2 to IF3 or the interface portions IF5 to IF6. However, as shown in FIG. 15, the micro concealment image 01 is constituted by the tenth interface IF10 made of a diffraction grating, and the periphery thereof is constituted by the eleventh interface IF11 which is a low-reflective interface. A contrast between light and dark is clearly attached, and authenticity determination can be performed reliably.

  Moreover, it is preferable to use bitmap data represented by a set of a plurality of dots (pixels) in the minute concealment image in the present invention. Bitmap data can be easily handled and processed by a computer, and high-resolution characters, symbols, and patterns can be expressed by appropriately changing the size and number of dots. Bitmap data here is one of the data formats for representing an image on a computer. The image is treated as being composed of many dots (dots) arranged in a grid, and A color or density expressed as a numerical value using a color system such as RGB (red, green, blue).

In addition, the electron beam exposure apparatus and laser exposure apparatus used for producing the original plate of the relief structure forming layer according to the present invention divides the drawing substrate into fine matrices, and converts the coordinate values of each point to digital data. As a drawing data, there are many things that will be drawn, and if bitmap data is used as drawing data, the compatibility with the exposure device is good and data will be lost at the time of drawing Is less likely to occur.
In addition, by making the dot size of the bitmap data sufficiently fine, it is possible to form a minute hidden image with very high resolution.

In order to realize a display body having a higher anti-counterfeit effect, it is preferable that the length of one side of the micro concealment image (micro characters) is 1 μm or more and 300 μm or less. When observing using an apparatus for magnifying observation such as an optical microscope, it is difficult to read image or character information if the length of one side of the micro concealment image (micro character) is 1 μm or less. At the same time, the area to be observed is limited, a sufficient amount of illumination light cannot be secured, and the low reflective interface portion may not be sufficiently black. Further, since it is generally difficult to recognize a structure of approximately 300 μm or less with the resolution of the human eye, the presence and information of minute concealment images (micro characters) can be easily grasped by setting the resolution to 300 μm or less. Since a means for magnifying observation such as a magnifying glass or an optical microscope is required for authenticity determination, a sufficient concealing effect can be expected.
Here, the length of one side of the minute concealment image is, for example, the length of the micro character string when the minute concealment image is composed of one line of the micro character string, and the length of the character width in the direction orthogonal to the character string. It means that.

  As the reflective layer 13 used in the present invention, for example, a metal layer made of a metal material such as aluminum, silver, gold, and alloys thereof can be used. Alternatively, a dielectric layer having a refractive index different from that of the relief structure forming layer 11 may be used as the reflective layer 13. Alternatively, as the reflective layer 13, a laminate of dielectric layers having different refractive indexes between adjacent ones, that is, a dielectric multilayer film may be used. The refractive index of the dielectric layer included in the dielectric multilayer film that is in contact with the relief structure forming layer 11 is preferably different from the refractive index of the relief structure forming layer 11. The reflective layer 13 can be formed by, for example, a vapor deposition method such as a vacuum evaporation method or a sputtering method.

  One of the relief structure forming layer 11 and the reflective layer 13 can be omitted. Here, the display body composed of only the reflective layer means a display using a metal layer, a dielectric layer, and a dielectric multilayer film as a relief structure forming layer. However, in the case where the display body 10 includes both the relief structure forming layer 11 and the reflective layer 13, compared to the case where only one of them is included, the previous interface is less likely to be damaged. An image with better visibility can be displayed.

  In addition, the reflective layer 13 may be covered on a part or all of the plurality of interface portions. For example, by using the distribution of the reflective layer 13, the outline of the region where the reflective layer exists is used. It can also be expressed. Further, the reflective layer 13 may be coated on the entire surface of the relief structure forming layer 11.

The display body in the present invention may further include other layers such as an adhesive layer and a resin layer.
The adhesive layer in the present invention is provided so as to cover the reflective layer, for example. When the display body includes both the relief structure forming layer and the reflection layer, the shape of the surface of the reflection layer is usually almost equal to the shape of the interface between the relief structure formation layer and the reflection layer. By providing the adhesive layer, it is possible to prevent the reflection layer surface from being exposed, so that it is difficult to duplicate the convex portion or concave portion of the previous interface for the purpose of counterfeiting.

  When the relief structure forming layer side is the back side and the reflective layer side is the front side, the adhesive layer is formed on the relief structure forming layer.

The resin layer in this invention can be provided in the front side with respect to the laminated body of a relief structure formation layer and a reflection layer.
When the relief structure forming layer side is the front side and the reflective layer side is the back side, damage to the relief structure forming layer is suppressed by covering the relief structure forming layer that is not provided with multiple interfaces with a resin layer. can do. In addition, when the relief structure forming layer side is the back side and the reflective layer side is the front side, by covering the reflective layer with a resin layer, damage to the reflective layer can be suppressed, and in addition, convex portions on the surface or Replication for the purpose of counterfeiting the recesses can be made difficult.

  Moreover, the display body in this invention can be affixed and used for printed matter and articles | goods through an adhesive material etc. as an anti-counterfeit label, for example. Since the display body has a minute concealment image having a light reflection preventing function due to a fine concavo-convex structure, it is difficult to forge or imitate, and when this label is supported on an article, the forged article with a label is genuine. Or imitation is also difficult.

  FIG. 16 is a plan view schematically showing an example of a labeled article in which an anti-counterfeit label is supported on the article. FIG. 17 is a cross-sectional view along the line XX-XX of the labeled article shown in FIG.

  16 and 17 illustrate a printed matter 100 as an example of a labeled article. This printed material 100 is an IC (integrated circuit) card and includes a base material 20. The base material 20 is made of plastic, for example. A concave portion is provided on one main surface of the substrate 20, and the IC chip 30 is fitted into the concave portion. Electrodes are provided on the surface of the IC chip 30, and information can be written to the IC and / or information recorded on the IC via these electrodes. A printed layer 40 is formed on the substrate 20. The display body 10 mentioned above is being fixed to the surface in which the printing layer 40 of the base material 20 was formed through the adhesion layer, for example. For example, the display body 10 is prepared as an adhesive sticker or a transfer foil, and is fixed to the base material 20 by being attached to the printing layer 40.

  The printed material 100 includes a display body 10 having a fine uneven structure. Therefore, it is difficult to counterfeit or imitate the same printed product 100. Moreover, since the printed material 100 further includes the IC chip 30 and the printed layer 40 in addition to the display body 10, it is possible to adopt a forgery prevention measure using them.

  16 and 17 illustrate an IC card as a printed material including the display body 10, but the printed material including the display body 10 is not limited to this. For example, the printed matter including the display body 10 may be another card such as a magnetic card, a wireless card, and an ID (identification) card. Alternatively, the printed matter including the display body 10 may be securities such as gift certificates and stock certificates. Alternatively, the printed matter including the display body 10 may be a tag to be attached to an article to be confirmed as a genuine product. Alternatively, the printed matter including the display body 10 may be a package body that contains an article to be confirmed to be genuine or a part thereof.

  Moreover, in the printed material 100 shown in FIG.16 and FIG.17, although the display body 10 is affixed on the base material 20, the display body 10 can be supported on a base material by another method. For example, when paper is used as the base material, the display body 10 may be rolled into the paper and the paper may be opened at a position corresponding to the display body 10. Alternatively, when a light-transmitting material is used as the base material, the display body 10 may be embedded therein, or the display body 10 may be fixed to the back surface of the base material, that is, the surface opposite to the display surface. .

  Moreover, the labeled article may not be a printed material. That is, the display body 10 may be supported on an article that does not include a printed layer. For example, the display body 10 may be supported by a luxury product such as a work of art.

The display body 10 may be used for purposes other than forgery prevention. For example, the display body 10 can be used as a toy, a learning material, or a decoration.

The top view which shows schematically the display body which concerns on 1 aspect of this invention. Sectional drawing along the II-II line of the display body shown in FIG. The perspective view which shows an example of the structure employable as the 1st interface part of the display body shown in FIG.1 and FIG.2. FIG. 4 is a plan view of the structure shown in FIG. 3. The figure which shows a mode that a diffraction grating inject | emits 1st-order diffracted light schematically. The figure which shows a mode that another diffraction grating inject | emits 1st-order diffracted light. The perspective view which shows an example of the structure employable as the 1st interface part of the display body shown in FIG.1 and FIG.2. The top view of the structure shown in FIG. The top view which shows schematically the display body which concerns on 1 aspect of this invention. The elements on larger scale of the structure shown in FIG. The conceptual diagram which shows the mode at the time of magnifying and observing the display body which concerns on 1 aspect of this invention. Sectional drawing along the IV-IV line of the display body shown in FIG. The conceptual diagram which shows the mode at the time of magnifying the conventional display body. Sectional drawing along the VV line of the display body shown in FIG. The conceptual diagram which shows the mode at the time of magnifying and observing another Example of the display body of this invention. The top view which shows roughly an example of the labeled article formed by making an anti-counterfeit label supported on the article. Sectional drawing along the XX-XX line of the labeled article shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 01 ... Micro concealment image, 10 ... Display body, 11 ... Light transmission layer, 13 ... Reflection layer, 20 ... Base material, 30 ... IC chip, 40 ... Printing layer, 100 ... Printed matter, 111 ... Light transmission base material, 112 ... light-transmitting resin layer, DA1 ... first display part, DA2 ... second display part, DA3 ... third display part, DA4 ... fourth display part, DA5 ... fifth display part, DA6 ... sixth display part, DA7 ... 7th display part, DA8 ... 8th display part, DA9 ... 9th display part, DA10 ... 10th display part, DA11 ... 11th display part, DL ... 1st order diffracted light, IF1 ... 1st interface part (low reflectivity Interface part), IF2 ... second interface part, IF3 ... third interface part, IF4 ... fourth interface part (low-reflective interface part), IF5 ... fifth interface part, IF6 ... sixth interface part, IF7 ... seventh Interface part, IF8 ... 8th interface part, IF9 ... 9th interface part, IF10 ... 10th interface part, IF11 ... 11 interface unit, IL ... illumination light, LS ... light source, NL ... normal, OR ... protrusion, PR ... protrusion, QR ... protrusion, RL ... regularly reflected light

Claims (9)

  One main surface of the relief structure forming layer includes at least a low reflective interface portion in which a plurality of convex portions or concave portions are disposed at a center-to-center distance less than the shortest wavelength of visible light, and the low reflective interface portion is minute A display body characterized by forming a concealed image.   The display body according to claim 1, wherein the minute concealment image is a micro character composed of a character, a symbol, a number, or a combination thereof.   The display body according to claim 1 or 2, wherein a length of one side of the micro concealment image is 1 µm or more and 300 µm or less.   The display body according to claim 1, wherein the minute concealment image includes a bitmap pattern.   The display body according to any one of claims 1 to 4, wherein a distance between centers of a plurality of convex portions or concave portions in the low reflective interface portion is 200 nm or more and less than 400 nm.   The display body according to any one of claims 1 to 5, wherein the height or depth of the plurality of convex portions or concave portions in the low reflective interface portion is ½ or more of the center-to-center distance.   The display body according to claim 1, wherein at least a part or all of the low-reflective interface is covered with a reflective layer.   8. The apparatus according to claim 1, further comprising: a reflective layer that covers at least a part or all of the low-reflectivity interface part; and a resin layer that covers the entire interface part. The display body.   A labeled article comprising the display according to any one of claims 1 to 8 and an article supporting the display.