JP2010204348A - Display body and article with label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display body capable of achieving higher forgery prevention effect than heretofore, and to provide an article with display body on which the display body is stuck as a label. <P>SOLUTION: The display body is composed of a relief structure formation layer having irregularities on one of the principal surfaces. The one principal surface is divided into a plurality of kinds of areas, some areas of which (a first interface part) are areas not generating diffracted light in the normal direction, and some other areas of which (a second interface part) are areas scattering visible light. In the first interface part, a plurality of projections or recesses are arranged so that distances between their centers are shorter than the shortest wavelength of visible light. In the second interface part, a plurality of projections or recesses linearly arrayed in almost uniform direction are arranged. Thus, when viewed from the normal direction of the principal surface, brightness is different between the first interface part of low reflection and low scattering and the second interface part of high scattering, and a visible image can be viewed. When viewed from an oblique direction, another image can be viewed. <P>COPYRIGHT: (C)2010,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. As can be seen from the above, it is difficult to manufacture the original plate used for manufacturing the display body including the relief type diffraction grating. Therefore, it is difficult to manufacture the display body including the relief type diffraction grating. .

  However, as a result of the use of display bodies including relief-type diffraction gratings in many articles that require anti-counterfeiting measures, this technology has become widely recognized, and along with this, the occurrence of counterfeit products tends to increase. is there. Therefore, it has become difficult to achieve a sufficient anti-counterfeit effect using a display body including a relief type diffraction grating.

  In addition, a display body that displays an image by controlling light scattering by a fine uneven structure is known (for example, Patent Document 3). A pattern displayed based on light scattering (hereinafter referred to as “light scattering pattern”) is usually formed by processing a concavo-convex structure on a base material of a display body. As the processing method, (1) etching method, (2) surface roughening with chemicals, etc. (3) sand blasting method in which fine sand-like particles are sprayed on the processing surface, (4) sharp structure at the tip There is a hairline process that brushes the processed surface with an apparatus having (5), or (5) a method of continuously forming irregularities over the entire surface by an electron beam (hereinafter referred to as EB) drawing apparatus. On the surface of the light scattering pattern processed by such a method, light is scattered, so that white or gray can be displayed.

  If an EB drawing apparatus is used, a minute concavo-convex structure can be precisely processed. Therefore, the arrangement density, shape, number, etc. of the concavo-convex structure formed on the substrate can be arbitrarily controlled and patterned on the substrate surface, and the degree of scattering, that is, the amount of scattered light can be controlled. is there.

For example, Patent Document 3 discloses an invention relating to an optical sheet in which a large number of minute concavo-convex structures are arranged on the surface, and by adjusting the arrangement density, shape, number, etc. of the concavo-convex structures,
(1) Character and picture display by light scattering pattern (2) Exquisite and diverse expression (3) Further improvement in design freedom is realized.

  Further, Patent Document 4 proposes an anisotropic scattering structure that can control the directionality of scattered light by defining the shape of the concavo-convex structure.

  These light scattering structures are used alone or in combination with a display body on which a relief-type diffraction grating pattern is formed. Since it can be realized by a plurality of methods as described above, it cannot be said that it exhibits a sufficient anti-counterfeit effect.

  In addition, it is impossible to express so-called “black” in a display body that uses a diffraction grating that splits rainbow-colored light and a display body that uses scattered light that exhibits white light.

JP-A-2-72320 US Pat. No. 5,058,992 JP 2002-333854 A JP 2008-107472 A

Junpei Takiuchi, "Holography", Maruzen Co., Ltd.

  An object of the present invention is to make it possible to achieve a higher anti-counterfeit effect.

That is, the invention according to claim 1 is a display body composed of a relief structure forming layer having unevenness on one main surface,
The one main surface is divided into a plurality of types of regions,
Among these plural types of regions, some regions (first interface portions) are regions that do not generate diffracted light in the normal direction of the one main surface, whereas at least some other regions (second regions). (Interface part) is a region that scatters visible light,
In the first interface portion, a plurality of convex portions or concave portions are arranged at a center-to-center distance less than the shortest wavelength of visible light,
In the second interface portion, a plurality of linear convex portions or concave portions having substantially uniform directions are arranged,
The display body is characterized in that a visible image is constituted by the arrangement of the first interface portion and the second interface portion.

The first interface portion according to the present invention is a region in which a plurality of convex portions or concave portions are arranged at a center-to-center distance that is less than the shortest wavelength of visible light. As will be described later, when a plurality of convex portions or concave portions are arranged at a minute center distance, no diffracted light of visible light is generated in the normal direction of the main surface. For this reason, reflection is reduced in this region, and light scattering is also reduced. As a result, black is displayed. On the other hand, the second interface portion is a region where a plurality of linear convex portions or concave portions having substantially uniform directions are arranged. Since the visible light incident on this region is scattered by the linear convex portion or concave portion, the second interface portion exhibits higher scattering than the first interface portion, and the scattered light is It is possible to observe from the normal direction of the main surface. And since these 1st interface parts and 2nd interface parts are arranged, when it observes from the normal line direction of the said main surface, the 1st interface part of low reflection and low scattering and the 2nd interface part of high scattering The brightness is different between and the visible image as a whole. Moreover, a visible image can also be comprised by contrast with the area | region where these 1st interface parts and 2nd interface parts do not exist.

  On the other hand, the first interface generates diffracted light in an oblique direction of the main surface. For this reason, when observed from an oblique direction, an image state different from a visible image observed from the normal direction of the main surface can be observed. For this reason, it is possible to achieve a higher anti-counterfeit effect.

  As described above, according to the present invention, a higher forgery prevention effect can be achieved.

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. Plan view of the structure shown in FIG. The figure which shows a mode that a diffraction grating inject | emits 1st-order diffracted light roughly The figure which shows a mode that another diffraction grating inject | emits 1st-order diffracted light schematically 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. Plan view of the structure shown in FIG. The perspective view which shows an example of the convex part and recessed part which can be employ | adopted as the 2nd interface part of the display body shown in FIG.1 and FIG.2. The perspective view which shows an example of the structure employable as the 2nd interface part of the display body shown in FIG.1 and FIG.2. The perspective view which shows an example of the convex part employable as the 2nd interface part of the display body shown in FIG.1 and FIG.2. The perspective view which shows an example of the structure employable as the 2nd interface part of the display body shown in FIG.1 and FIG.2. The top view which shows a mode that the area of the pixel in which the 1st interface part was formed was changed. The top view which shows a mode that the area of the pixel in which the 2nd interface part was formed was changed. Explanatory drawing which shows the example of arrangement | positioning of a 1st interface part and a 2nd interface part Explanatory drawing which shows the example of arrangement | positioning of a 1st interface part and a 2nd interface part Explanatory drawing which shows the example of arrangement | positioning of a 1st interface part and a 2nd interface part The top view which shows roughly an example of the labeled article | item which makes the article support the label for forgery prevention Sectional drawing along the III-III 'line of the labeled article shown in FIG.

  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. FIG. 2 is a cross-sectional view taken along the line II-II ′ of the display shown in FIG. The display body 10 includes a laminated body of a light transmission layer 11 and a reflection layer 13. In this example, the light transmission layer 11 is a relief structure forming layer. In the example shown in FIG. 2, the light transmission layer 11 side is the front side (observer side) and the reflection layer 13 side is the back side.

  The main surface of the light transmissive layer 11, that is, the interface between the light transmissive layer 11 and the reflective layer 13, is divided into a plurality of regions, and some of the regions are the first interface portion IF1 and other portions. This region is the second interface IF2. Each of these first interface portion IF1 and second interface portion IF2 is a region where minute irregularities are formed. As will be described later, the irregularities of the first interface portion IF1 and the irregularities of the second interface portion IF2 are: Its structure and properties are different.

  As a material of the light transmission layer 11, for example, a resin having light permeability such as a thermoplastic resin or a photocurable resin can be used. When a thermoplastic resin or a photocurable resin is used, for example, a convex structure and / or a concave structure is provided on one main surface from a metal stamper on which a convex structure and / or a concave structure of the display body is formed. The light transmission layer 11 can be transfer-molded.

  In FIG. 2, as an example, the light transmissive 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 light transmissive 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 a stamper against the coating film.

  As the reflective layer 13, 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 light transmission 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 light transmission layer 11 is preferably different from the refractive index of the light transmission 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.

  The display body 10 can further include other layers such as an adhesive layer and a resin layer. For example, the adhesive layer is provided so as to cover the reflective layer 13. When the display body 10 includes both the light transmissive layer 11 and the reflective layer 13, the shape of the surface of the reflective layer 13 is usually almost equal to the shape of the interface between the light transmissive layer 11 and the reflective layer 13. When the adhesive layer is provided, it is possible to prevent the surface of the reflective layer 13 from being exposed, so that it is difficult to duplicate the convex structure and / or the concave structure of the previous interface for the purpose of counterfeiting.

  When the light transmission layer 11 side is the back side and the reflection layer 13 side is the front side, the adhesive layer is formed on the light transmission layer 11. In this case, not the interface between the light transmission layer 11 and the reflection layer 13, but the interface between the reflection layer 13 and the outside includes the interface portions IF1 to IF2.

  The resin layer is provided on the front side with respect to the laminated body of the light transmission layer 11 and the reflection layer 13. For example, in the case where the light transmission layer 11 side is the back side and the reflection layer 13 side is the front side, by covering the reflection layer 13 with a resin layer, damage to the reflection layer 13 can be suppressed, The duplication of the convex structure and / or the concave structure for the purpose of counterfeiting can be made difficult.

(Description of the first interface)
In describing the first interface IF1 according to the present invention, first, the relationship between the center-to-center distance and wavelength of the diffraction grating and the presence or absence of the generation of diffracted light will be described.

  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 exit angle β of m-order diffracted light (m = 0, ± 1, ± 2,...) DL can be calculated from the following equation when the light travels in a plane perpendicular to the grating line of the diffraction grating. it can.

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 the 0th-order diffracted light RL, that is, the transmitted light or the regular reflection light RL. 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 specularly reflected 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, an observer who observes from the normal direction cannot observe the diffracted light.

  Further, there is the following difference in the first-order diffracted light DL between the case where the grating constant d of the diffraction grating is larger than the wavelength λ and the case where it is smaller than the wavelength λ.

  That is, FIG. 5 is a principle view schematically showing a state in which a diffraction grating having a grating constant d larger than the wavelength λ emits first-order diffracted light. FIG. 6 is a principle diagram schematically showing a state in which a diffraction grating having a grating constant d larger than the wavelength λ emits first-order diffracted light. 5 and 6, GR represents an interface on which a diffraction grating is formed, NL represents a normal line of the interface GR, IL represents illumination light, RL represents regular reflection light or zero-order diffracted light, and DL represents 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 wavelength λ, when the illumination light IL is irradiated obliquely with respect to the interface IF, the diffraction grating is as shown in FIG. The first-order diffracted light DL is emitted at an emission angle β within a positive angle range.

On the other hand, when the grating constant d of the diffraction grating is smaller than the wavelength λ, when the illumination light IL is irradiated from an oblique direction to the interface GR, the diffraction grating has a negative angular range as shown in FIG. The first-order diffracted light DL is emitted at an inner emission angle β. For example, considering the case where the angle α is 50 ° and the grating constant d is 330 nm, the diffraction grating emits first-order diffracted light having a wavelength λ of 540 nm at an emission angle β of about 60 °.

  To summarize the above explanation, first, when the grating constant d of the diffraction grating is larger than the wavelength λ, the diffraction grating generates diffracted light in the normal direction. On the other hand, when the grating constant d of the diffraction grating is smaller than the wavelength λ, the diffraction grating does not generate diffracted light in the normal direction and emits the first-order diffracted light DL in the negative angle range.

  Next, the structure and optical properties of the first interface part IF1 will be described.

  The first interface portion IF1 is provided with a plurality of dot-shaped convex portions PR arranged at a center-to-center distance less than the shortest wavelength of visible light.

  For this reason, the first interface IF1 does not generate visible diffracted light in the normal direction, and emits the first-order diffracted light DL in a negative angle range. Therefore, when observed from the normal direction, the first interface IF1 does not display a spectral color due to diffraction. That is, the first interface IF1 is visually recognized as a dark gray or black print layer.

  Therefore, for example, when the display body 10 is observed from the normal direction, the first interface portion IF1 looks dark. Typically, the first interface IF1 appears 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 first interface IF1 looks like a dark gray or black print layer, for example.

  In the first interface portion, the brightness and saturation decrease as the distance between the centers of the plurality of protrusions or recesses decreases, enabling a blacker display, and slightly increasing as the distance between the centers increases. The brightness increases and the structure is perceived as dark gray.

  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 interface portion IF1 can display diffracted light.

  In addition, it is desirable that the convex portion or the concave portion provided in the first interface portion IF1 has a shape in which the cross-sectional area gradually increases or decreases in the normal direction.

  When such a structure is employed, the distance between the centers of the projections PR is shorter than the shortest wavelength of visible light, so the first interface IF1 is optically arranged in the thickness direction of the display body 10. This is equivalent to having a continuously changing refractive index. Therefore, the reflectance of the first interface part IF1 is small. For this reason, the color when observed from the normal direction is closer to black. In addition, since the luminance of the first-order diffracted light emitted in the negative angle range also decreases, the color looks like a dark gray or black print layer even when observed from this angle.

  When the convex portion or the concave portion has a shape in which the cross-sectional area gradually increases or decreases in the normal direction, the larger the height or depth of the convex portion or the concave portion, the lower the reflectance, and the more black display is. It becomes possible, and as the height and depth become smaller, the brightness increases and it is perceived as dark gray. Typically, it is desirable that the height and depth be 1/2 or more of the center-to-center distance. Specifically, for example, when the center-to-center distance is 400 nm, dark gray display is possible by setting the height or depth to 200 nm or more, and black display by setting the height or depth to 400 nm or more. Is possible. If the structure is much higher or deeper 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. However, it is at most 1 μm or less. Here, the height of the convex part or the depth of 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.

  FIG. 3 is a perspective view showing an example of a structure that can be employed in the first interface portion IF1 of the display body shown in FIGS. FIG. 4 is a plan view of the structure shown in FIG. In FIG. 3, the interface part IF1 viewed from the transparent layer 11 side is depicted.

  The first interface portion IF1 is provided with a plurality of convex portions PR arranged at a center-to-center distance less than the shortest wavelength of visible light. In the example shown in FIG. 3, the convex portions PR are arranged in a lattice pattern in the x and y directions substantially orthogonal to each other, but the convex portions PR have a lattice arrangement that intersects in a different direction. May be. In either case, the convex part PR has a dot shape.

  Further, in the first interface portion IF1, each convex portion PR has a shape (tapered shape) having a tapered side surface, and thus has a structure in which the cross-sectional area gradually increases or decreases. A part of the convex part PR may not have a tapered shape.

  The tapered shape is, for example, 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. The side surface of the convex part PR may be composed only of an inclined surface or may be stepped. The tapered shape is useful for reducing the light reflectance of the first interface portion IF1. In addition, the taper shape facilitates the removal of the light transmission layer 11 from the original plate and contributes to the improvement of productivity.

  In the first interface IF1, the plurality of convex portions PR function in substantially the same manner as a diffraction grating in which grooves (that is, lattice lines) are arranged in a lattice shape corresponding to the arrangement.

  Next, FIG. 7 shows a structure that can be employed in the first interface IF1 of the display body shown in FIGS. 1 and 2, and is different from the structure of FIG. It is a perspective view showing 1 interface part. Here, the non-lattice arrangement means a state of irregular arrangement without a periodic arrangement rule. FIG. 8 is a plan view of the structure shown in FIG. In FIG. 7, the first interface portion IF1 viewed from the relief structure forming layer 11 side is depicted.

  As shown in FIG. 7, the first interface portion IF1 is provided with a plurality of convex portions PR arranged in a non-lattice manner so that the distance between the centers of the convex portions PR is less than the shortest wavelength of visible light. Placed in. 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. Unlike the first interface IF1 shown in FIG. 3, the first interface IF1 composed of the irregularly arranged convex portions PR is difficult to observe the first-order diffracted light DL. For example, the display body When 10 is observed from the normal direction, it is visually recognized as a dark gray or black print layer.

The center-to-center distance between the convex part and the concave part is preferably 100 nm or more.
If it is shorter than 100 nm, the production of the original plate and the replication from the stamper become technically more advanced.

(Description of the second interface)
Next, the second interface portion IF2 will be described.

  The second interface portion IF2 is a relief structure having a concave-convex shape in the same manner as the interface portion IF1, but the distance between the centers of the convex portions and the concave portions is typically much larger than the visible wavelength, and at least the maximum visible wavelength ( 700 nm) or more. Diffracted light due to light diffraction is unlikely to be generated by such convex portions and concave portions having a large center-to-center distance, and mainly only light scattering characteristics are exhibited as optical characteristics.

  And the convex part and recessed part of 2nd interface part IF2 are exhibiting the linear structure where each direction (azimuth angle) is substantially equal. Each structure provided in the second interface portion IF2 is typically a rectangular convex portion or concave portion having a long side and a short side as shown in FIG. 9, and the second interface portion IF2 has a structure as shown in FIG. In addition, a plurality of such structures are formed. For this reason, it distinguishes from the center-to-center distance of the convex part and the concave part in the interface part IF1, and the distance between the rectangular convex parts or concave parts arranged adjacent to each other is called the arrangement interval, and the average is the average arrangement interval Call.

  When the second interface portion IF2 is irradiated with light from the normal direction, the second interface portion IF2 has a wide exit angle in a plane perpendicular to the long side direction of the plurality of linear convex portions and concave portions. Scattered light is emitted in the range. On the other hand, scattered light is emitted in a narrow emission angle range in a plane parallel to the long side direction of the linear convex portion and the concave portion and perpendicular to the main surface of the interface portion IF2. Hereinafter, the size of the angle range in which the light scattering region emits scattered light having a certain light intensity or higher is expressed by the term “light scattering ability”. For example, when the term “light scattering ability” is used, the above explanation is “the light resolution in the long side direction of the linear protrusion and / or recess is low, and the light scattering ability is high in the direction perpendicular thereto. In other words. In addition, a structure capable of obtaining a sufficiently different light scattering ability depending on an observation direction is referred to as an “anisotropic light scattering structure”.

  When the second interface IF2 is visually observed under the observation condition that the light scattering ability is high under illumination of general white illumination light, the second interface IF2 is perceived as white or grayish white having a slightly lower brightness than white, and light scattering. Scattered light does not reach under the observation conditions where the performance is low, and the color corresponding to the material is perceived as it is in the second interface IF2. For example, when the structure provided at the second interface IF2 is covered with a silver reflective layer such as silver or aluminum, the silver metallic luster is perceived as it is. In other words, a color whose brightness is lower than the color reflected from the reflective layer cannot be expressed.

  Here, “white” refers to a state in which the display 10 is irradiated with light from the normal direction and the brightness of the scattered light reaching the observer is 90% or more, and “gray white” is 75% brightness. It means a state as described above.

  Here, the length of the long side of the linear convex part or the concave part is preferably 10 μm or more and 100 μm or less, for example. Moreover, the length of the short side of the linear convex part or the concave part is preferably 1 μm or more and less than 10 μm. In order to change the light scattering ability according to the illumination conditions and the observation position, it is desirable that the difference between the length of the long side and the length of the short side is larger, and the difference between the length of the long side and the short side is 10 times or more. Still good.

In addition, the convex portion or concave portion of the second interface portion and the convex portion or concave portion provided in the first interface portion can be easily formed by pressing a stamper or the like in the same process. It is desirable that the height of the convex part and the depth of the concave part are approximately the same. As described above, since the height of the first interface convex portion and the depth of the concave portion are 1 μm at most, the height of the convex portion and the depth of the concave portion of the second interface portion may be 1 μm or less.

  In addition, the structure provided in the interface IF2 exhibits light scattering characteristics even when the cross-sectional shape is not rectangular as shown in FIG. 11 or when a plurality of shapes are combined as shown in FIG. can do.

  Further, it is desirable that these convex portions and concave portions are formed at an average interval of 10 μm or more and 100 μm or less. If it is smaller than 10 μm, a plurality of convex portions or concave portions function like a diffraction grating, and emit not only scattered light but also diffracted light. As a result, sufficient light scattering ability cannot be obtained, and the rainbow color shines, resulting in a visual effect similar to a conventional diffraction grating pattern. On the other hand, when the average interval exceeds 100 μm, in order to obtain a sufficient light scattering ability, for example, it is necessary to produce a high convex part or a deep concave part exceeding 100 μm, which makes it difficult to produce with an EB lithography apparatus. .

  Further, as a structure provided in the second interface part IF2, it is more preferable that structures having different long sides, short sides, and different heights and depths are arranged at various arrangement intervals. If the long and short sides of the structure to be provided, the height and depth of the structure, and the arrangement interval are not uniform or regular, it becomes rough when the second interface IF2 is macroscopically observed. The effect of scattering light becomes higher.

  Here, when the anisotropic light scattering structure of the second interface portion IF2 is used by being attached to a medium that needs to be prevented from forgery, the color and light scattering ability that can be seen under observation conditions with high light scattering ability are obtained. Since there is a difference in color seen under low viewing conditions, it achieves a visual effect that is difficult to achieve with inks used in ordinary printed materials, and exhibits anti-counterfeit functions.

  However, with such a scattering structure alone, the change in the visual effect (observed color) accompanying the change in the observation conditions is not so large, and it is difficult to exert a sufficient anti-counterfeit effect.

  In addition, it is good to produce so that the linear convex part and recessed part provided in a 2nd interface part may occupy the area of about 40%-60% in the area | region of a 2nd interface part. When the concavo-convex structure is 50% in the plane, the light scattering ability with respect to the fixed point is the highest. The light scattering ability tends to decrease as the occupation ratio increases or decreases. Therefore, in order to change the light scattering ability greatly according to the illumination conditions and the observation position, and to express the difference between light and dark clearly, the straight convex part or concave part has an area occupied by 50% in the plane of the second interface part. It is desirable to be formed, and if the occupation area is about 40% to 60%, a sufficient effect is expected.

(Visual effect realized by the first interface and the second interface formed in a minute area)
Here, a visual effect realized by the first interface portion IF1 and the second interface portion IF2 shown in the display body according to one embodiment of the present invention in FIG. 1 will be described.

  The first interface portion IF1 and the second interface portion IF2 are each formed in a minute region, and it is difficult to distinguish each region when macroscopically observed with the naked eye. When the display body 10 is irradiated with light from the normal direction of the main surface and the display body 10 is observed from the point A, the first interface portion IF1 exhibits an anti-reflection effect, so that the first interface portion IF1 can observe the display body 10. Very little if any light reaches the direction. On the other hand, since the second interface IF2 is provided with a large number of rectangular concavo-convex structures that are long in the X direction, the observer can transmit white or gray-white light to the observer at the point A due to high light scattering ability. Can perceive. Since the surface of the display body 10 is divided into the first interface portion IF1 and the second interface portion IF2, the amount of scattered light reaching the observer from the second interface portion is only on the display body. Although it is slightly lower than the case where it is provided, the observer can still perceive white or grayish white close to white.

  Further, when the display body 10 is irradiated from the normal direction of the main surface to the display body 10 and the display body 10 is observed from the point B where the 90 ° azimuth is changed from the point A, the first interface IF1 is at the point A. Since the antireflection effect is exhibited in the same manner as when observed, there is very little or no light emitted in the direction of the observer, and it appears black or dark gray. Then, since the second interface portion IF2 is in an observation condition in which the light scattering ability is lowered, the scattered light hardly reaches. Therefore, the color perceived by the observer at the point B is dark gray in which black and the color of the reflective layer are mixed. This effect can be seen both when the observer observes the display body 10 from different positions of the points A and B and when the position of the illumination light changes by 90 °.

  Thus, the display body 10 exhibits a white (or grayish white) and black (or dark gray) color change according to the observation conditions by the plurality of first interface parts IF1 and second interface parts IF2. There has never been a structure that changes color between white (or grayish white) and black (or dark gray) by changing the illumination light or the position of the observer by 90 °, and exhibits a high anti-counterfeiting effect.

(Arrangement of each interface)
By the way, it is desirable that the first interface portion and the second interface portion are arranged as follows on one main surface of the display body.

  That is, the one main surface is divided into a plurality of pixels arranged two-dimensionally, a plurality of pixels among the plurality of pixels are made to correspond to the first interface portion, and the other plurality of pixels are set to the second pixel. Corresponding to the interface. As described above, since the visual effect of the first interface portion is different from the visual effect of the second interface portion, a visible image can be expressed as a whole based on the difference between these visual effects.

  In addition, the area | region in which neither the 1st interface part and the 2nd interface part on a display body are formed can be made into a flat surface, a diffraction grating formation layer, a hologram formation layer, a printing formation surface etc., for example. They can also be omitted.

  As shown in FIGS. 13 and 14, when the first interface portion IF1 and the second interface portion IF2 are provided as pixels on the display body and the size of each pixel is changed, the antireflection effect by the first interface portion IF1 is achieved. And the degree of light scattering effect by the second interface IF2 can be arbitrarily controlled. The first interface IF1 can increase the antireflection effect of the portion by increasing the area of the pixel, and can display darker black. By reducing the area of the pixel, the antireflection effect at that portion is reduced. The second interface portion IF2 can display lighter white color by increasing the light scattering ability of the portion by increasing the area of the pixel. By reducing the area of the pixel, the light scattering ability of that portion is lowered.

  In addition, by using a pixel structure, it is possible to easily display images such as pictures, characters, symbols, and the like.

  With the fine pixel structure, separate images are formed at the first interface portion IF1 and the second interface portion IF2, and the display body is observed from the point A and the point B by arranging each pixel in order with periodicity. In this case, it is possible to observe different images.

As shown in FIG. 15, when the first interface portion IF1 and the second interface portion IF2 are alternately arranged adjacent to each other in a checkered pattern and light is irradiated from the normal direction of the main surface of the display body, the point A is on the display body. Scattered light reaches the observer through the second interface IF2 provided on the display surface, and the surface of the display body appears to shine white. On the other hand, when the display body is observed from the point B, the scattered light from the second interface IF2 hardly reaches and the image (here, the alphabet “S”) formed by the first interface IF1 is black. Is displayed. The arrangement rule of the pixel group of the first interface part IF1 and the pixel group of the second interface part IF2 is not limited to the checkered pattern arranged alternately and adjacently, but by a stripe arrangement as shown in FIG. The arrangement may be such that appearance rules are different between the first interface part IF1 and the second interface part IF2. In FIG. 15, the pixels of the first interface IF1 are indicated by black rectangles, the pixels of the second interface IF2 are indicated by gray rectangles, and individual protrusions or recesses formed inside are omitted. It is assumed that a plurality of rectangular structures that are long in the X direction are formed inside the second interface IF2. Further, by further reducing the size of these pixels, an image with higher resolution can be displayed.

  The pixel shape of the first interface portion is desirably a shape that is included in a rectangular shape having a side of 1 μm or more and 300 μm or less. The center-to-center distance of the structure composed of convex portions and concave portions formed in the first interface portion is smaller than the shortest wavelength of visible light, and is about 0.1 to 0.5 μm. In order to exhibit a sufficient antireflection effect by continuously arranging a plurality of convex portions or concave portions at such a center distance, at least about ten convex portions or concave portions are arranged in one direction. Is desirable. Therefore, the area of the first interface portion should be large enough to contain a rectangle having a side of 1 μm or more. Further, when the first interface portion has an area exceeding a rectangle having a side of 300 μm, the pixel shape is perceived, resulting in poor quality image display. In order to display a high-definition image, the image is preferably composed of pixels that are smaller than the resolution of a general human eye and fit in a rectangle with a side of 300 μm or less.

  The pixel shape of the second interface portion is desirably a shape that is enclosed in a rectangular shape with sides of 30 μm or more and 300 μm or less. In order to obtain sufficient light scattering ability by the plurality of linear convex portions and concave portions formed at the second interface portion, the length of the long sides of the linear convex portions and concave portions is, for example, 10 μm or more, and 100 μm or less. Further, the length of the short side is preferably 1 μm or more and less than 10 μm, for example. Further, the average arrangement interval of these structures is preferably in the range of 10 μm or more and 100 μm or less. Therefore, the pixel shape is desirably a shape that is enclosed in a rectangle having a side of 30 μm or more.

(How to use the display)
The display body 10 described above can be used, for example, by sticking it to a printed matter or an article other than that through an adhesive or the like as an anti-counterfeit label. Since the display body 10 has an image having an anti-light reflection function due to a fine concavo-convex structure, it is difficult to counterfeit or imitate, and when this label is supported on an article, the label article that is genuine is forged or Imitation is also difficult.

  FIG. 18 is a plan view schematically showing an example of a labeled article in which an anti-counterfeit label is supported on the article. 19 is a cross-sectional view of the labeled article shown in FIG. 18 taken along line III-III ′.

  18 and 19 show 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 information recorded on the IC can be read through 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.

  In FIG. 18 and FIG. 19, an IC card is illustrated 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 matter 100 shown in FIG.18 and FIG.19, 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.

DESCRIPTION OF SYMBOLS 10 ... Display body, 11 ... Light transmissive layer, 111 ... Light transmissive base material, 112 ... Light transmissive resin layer, 13 ... Reflective layer, 20 ... Base material, 30 ... IC chip, 40 ... Print layer, 100 ... Printed matter GR: diffraction grating, IF1: first interface portion, IF2: second interface portion, PR: convex portion, QR: convex portion, SR: concave portion, DL: first-order diffracted light, IL: illumination light, NL: normal, RL ... Specular reflection light

Claims (13)

A display body comprising a relief structure forming layer having irregularities on one main surface,
The one main surface is divided into a plurality of types of regions,
Among these plural types of regions, some regions (first interface portions) are regions that do not generate diffracted light in the normal direction of the one main surface, whereas at least some other regions (second regions). (Interface part) is a region that scatters visible light,
In the first interface portion, a plurality of convex portions or concave portions are arranged at a center-to-center distance less than the shortest wavelength of visible light,
In the second interface portion, a plurality of linear convex portions or concave portions having substantially uniform directions are arranged,
A display body characterized in that a visible image is constituted by the arrangement of the first interface portion and the second interface portion. The one main surface is divided into a large number of pixels arranged two-dimensionally,
2. The display body according to claim 1, wherein a plurality of pixels among the plurality of pixels correspond to the first interface portion, and a plurality of other pixels correspond to the second interface portion.   A plurality of pixels (first pixel group) corresponding to the first interface portion and a plurality of pixels (second pixel group) corresponding to the second interface portion are arranged regularly with periodicity. The display body according to claim 2.   4. The display body according to claim 2, wherein each of the first pixels is formed in a region included in a rectangle having a side of 1 μm or more and 300 μm or less. 5.   The display body according to claim 2, wherein each of the second pixels is formed in a region included in a rectangle having a side of 30 μm or more and 300 μm or less.   The distance between the centers of the plurality of protrusions or recesses provided at the first interface is 100 nm or more and less than the shortest wavelength of visible light, and the height of the protrusions or the depth of the recesses is 1 of the center distance. It is / 2 or more, The display body in any one of Claims 1-5 characterized by the above-mentioned.   The display body according to claim 1, wherein convex portions or concave portions provided in the second interface portion are formed at an average interval of 10 μm or more and 100 μm or less.   The linear convex part or concave part provided in the second interface part is rectangular, the long side length is 10 μm or more and 100 μm or less, and the short side length is 1 μm or more and less than 10 μm. The display body according to claim 1, wherein the display body is a display body.   The linear convex part or recessed part provided in the said 2nd interface part is a rectangle, and a long side has an average length 10 times or more of a short side, In any one of Claims 1-8 characterized by the above-mentioned. Display body of description.   The linear convex part or recessed part is formed in the area | region of the said 2nd interface part with the area ratio of 40% or more and 60% or less, The one in any one of Claims 1-9 characterized by the above-mentioned. Display body.   The display body according to claim 1, wherein at least a part of the convex portion or the concave portion is covered with a reflective layer.   The display body according to claim 1, further comprising a reflective layer covering at least a part of the convex portion or the concave portion and a resin layer covering the convex portion or the concave portion.   An article with a label, comprising: the display body according to any one of claims 1 to 12; and an article that supports the display body as a label.

Images