JP2011218648A - Display body and labeled article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display body for exhibiting a high forgery preventing effect.SOLUTION: The display body comprises: a light-transmissive base material; a concavo-convex structure-formed layer arranged on one surface side of the base material; a light reflection layer for covering at least a part of the concavo-convex structure-formed layer; and a printed layer arranged on the surface, on which the concavo-convex structure-formed layer of the base material is not formed or the surface which is contacted with the light reflection layer. At least a part of the concavo-convex structure-formed layer has such a structure that a plurality of convex parts each having the upper surface almost parallel to the surface of the base material, or a plurality of concave parts each having the bottom surface almost parallel to the surface of the base material, and a flat part almost parallel to the surface of the base material are arranged.

Description

  The present invention relates to a display technology that provides 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. The display body which has a different visual effect is affixed. 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 having a visual effect different from that of a normal printed material, 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 condition, or can display a stereoscopic image. Further, the spectral color shining in rainbow colors expressed 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.
For example, Non-Patent Document 1 describes the principle that incident light (white light) changes to a rainbow-colored spectral color by the diffraction grating.

In a display body using a diffraction grating, a relief type diffraction grating formed with a plurality of grooves is generally used. A relief type diffraction grating is usually obtained by replicating an original plate produced using photolithography as a mother die. For example, Patent Document 1 and Patent Document 2 display a picture by appropriately changing the grating angle and the grating interval (grating pitch) of the diffraction grating by utilizing the spectral color that the diffraction grating shines in rainbow colors. Is described. In the display formed by a plurality of diffraction grating structures with different grating angles and intervals, the wavelength of the diffracted light that reaches the eyes of the observer gradually changes as the position of the observer and the position of the light source change. Thus, an image that changes to a rainbow color can be expressed.
In addition, in these documents, as a method for producing an original plate of a relief type 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. Describes a method of exposing the photosensitive resist to a pattern by irradiating the photosensitive resist with an electron beam while moving. Non-Patent Document 2 describes a method of forming a diffraction grating using two-beam interference. In the manufacture of the relief type diffraction grating, the original stamp obtained in this way is usually used, and a metal stamper is produced therefrom by a method such as electroforming.

  Next, using this metal stamper as a matrix, a relief type diffraction grating is duplicated. That is, first, for example, a thermoplastic resin or a photocurable resin is applied to a film or sheet-like thin transparent substrate made of polyethylene terephthalate (PET) or polycarbonate (PC). Next, a metal stamper is brought into close contact with the coating film, and heat or light is applied to the resin layer in this state. After the resin is cured, the metal stamper is peeled from the cured resin to obtain a replica of the relief type diffraction grating.

Generally, this relief type diffraction grating is transparent. Therefore, usually, a reflective layer is formed on a resin layer provided with a relief structure by depositing a metal such as aluminum or a dielectric in a single layer or multiple layers by vapor deposition.
Then, the display body obtained in this way is affixed on the base material which consists of paper or a plastic film through an adhesive layer or an adhesion layer, for example. As described above, a display body with anti-counterfeit measures is obtained.

  An original plate used for manufacturing a display including a relief type diffraction grating is difficult to manufacture. Further, the transfer of the relief structure from the metal stamper to the resin layer must be performed with high accuracy. That is, high technology is required for manufacturing a display body including a 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. For this reason, it has become difficult to achieve a sufficient anti-counterfeit effect using a display body that is characterized only by exhibiting rainbow light by diffracted light.

JP-A-2-72320 US Pat. No. 5,058,992

Edited by Junpei Takiuchi, "Holographic Display", Sangyo Tosho Co., Ltd. Junpei Takiuchi, "Holography", Maruzen Co., Ltd.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a display body and a labeled article that exhibit a high anti-counterfeit effect.

In order to achieve the above object, the first invention covers a light-transmitting base material, a concavo-convex structure forming layer provided on one surface side of the base material, and at least a part of the concavo-convex structure forming layer On the substrate surface opposite to the surface on which the light reflecting layer and the concavo-convex structure forming layer are provided, between the concavo-convex structure forming layer and the light reflecting layer, and the concavo-convex structure forming layer of the light reflecting layer; A printed layer formed on any one of the surfaces opposite to the surface in contact therewith, wherein the concavo-convex structure forming layer has a plurality of top surfaces substantially parallel to the substrate surface A plurality of concave portions having convex portions or bottom surfaces substantially parallel to the base material surface, and at least one first region configured by arranging a flat portion substantially parallel to the base material surface; The plurality of convex portions or concave portions have a long side and a short side length of 0.3 μm or more and 10 μm or less, respectively. The height of the part or the recess is not less than 0.1 μm and not more than 0.5 μm, and the protrusion or the recess is arranged in an orderly or non-ordered manner in the first region, and the convex in the first region The display body is characterized in that the area occupied by the portion or the recess is 20% or more and 80% or less.
The second invention displays a display color having a predetermined hue by light composed of a combination of a plurality of visible light wavelengths under normal illumination conditions, and the display under conditions other than normal illumination conditions. Has the function of not displaying the color,
The display body according to claim 1, wherein:
According to a third aspect of the present invention, at least a part of the printed layer has a color perceived as substantially the same color as a display color by a combination of the plurality of visible light wavelengths when observed under the normal illumination conditions. 3. The display body according to claim 1, wherein the display body is formed of ink or toner to be displayed.
According to a fourth aspect of the present invention, at least a part of the printed layer is formed of a functional ink having a different color depending on a light source or an observation angle. It is a display body of description.
The fifth invention is characterized in that a latent image pattern in which a display image changes according to an observation angle is formed by the printing layer or the concavo-convex structure forming layer. It is a display body of a crab.
According to a sixth aspect of the present invention, at least one of a diffraction grating, an antireflection structure, a light scattering structure, and a flat portion is formed in a second region that differs in structure and optical properties from the first region. The display body according to claim 1, wherein the display body is a display body.
The seventh invention is a labeled article comprising the display according to any one of claims 1 to 6 and an article supporting the display.

According to the first aspect of the present invention, according to the first invention, the plurality of convex portions whose upper surface is substantially parallel to the base material surface, or the plurality of concave portions whose bottom surface is substantially parallel to the base material surface, and the base material surface A display body capable of displaying colors composed of light of a plurality of wavelengths according to the incidence of illumination light is obtained by the first region configured by arranging flat portions substantially parallel to the light. Unlike the relief-type diffraction grating pattern, this display body does not change its color to iridescent according to changes in the position of the illumination or the position of the observer, and is different from the conventional anti-counterfeit medium using a diffraction grating. The effect can be realized. As a result, a display body that exhibits a high anti-counterfeit effect can be obtained.
Further, according to the second invention, since the display body has the print layer, the combination of the first region that exhibits a color change according to the observation condition and the region by the print layer that hardly causes the color change can satisfy the observation condition. The display image can be changed accordingly, and a visual effect different from that of a normal printed matter or a diffraction grating pattern can be realized. As a result, a display body that exhibits a high anti-counterfeit effect can be obtained.
According to the third aspect of the invention, a display body that is perceived as substantially the same color under normal lighting conditions and perceived as different colors under conditions other than normal lighting conditions is obtained.
According to the fourth invention, by forming the print layer using the functional ink, it is possible to obtain a display body in which both the print layer and the first region change in color according to the observation conditions.
In addition, according to the fifth invention, by forming a latent image pattern as a display image, not only the color change of the print layer and the first area, but also the visual effect of the appearance and disappearance of the display image according to the observation conditions Can be realized.
According to the sixth invention, the design of the display body is further enhanced by providing the display body with a second region comprising any of a diffraction grating, an antireflection structure, a light scattering structure, and a flat portion. As well as a higher anti-counterfeit effect.
Further, according to the seventh invention, it is possible to give a high anti-counterfeiting effect to a conventional article by pasting or combining the display body of the present invention on a printed matter, a card, or another article.

The top view which showed roughly the display body which concerns on 1 aspect of this invention. The expanded sectional view of the display body which follows the II-II line of FIG. The expanded sectional view which shows another structural example of the display body which follows the II-II line | wire of FIG. The expanded sectional view which shows another structural example of the display body which follows the II-II line | wire of FIG. The figure which showed roughly a mode that the diffraction grating with a narrow pitch inject | emits + 1st-order diffracted light. The figure which showed roughly a mode that the diffraction grating with a wide pitch inject | emits + 1st-order diffracted light. The top view which shows an example of the structure which can be employ | adopted as the 1st area | region of the display body of this invention. The expanded sectional view of the display body which follows the III-III line of FIG. The top view which shows another example of the structure employable as a 1st area | region. Schematic which shows the mode of the diffracted light inject | emitted from a diffraction grating. The figure which shows the mode of the diffracted light inject | emitted from the 1st area | region. Sectional drawing which shows an example of the diffraction grating whose top part and bottom part are not flat. Sectional drawing which shows another example of the diffraction grating whose top part and bottom part are not flat. The top view which shows an example of the 1st area | region and 2nd area | region arrange | positioned at a display body. The top view which shows the example of arrangement | positioning of several 1st area | regions. The top view which shows another example of arrangement | positioning of a some 1st area | region. The top view which shows another example of arrangement | positioning of a some 1st area | region. The top view which shows the display body by the 1st area | region and print area which are perceived by substantially the same color on normal illumination conditions. Explanatory drawing which shows a mode that the display body of FIG. 18 was observed on conditions other than normal illumination conditions. The top view which shows the display body by the 1st area | region perceived with a different color on normal illumination conditions, and the printing area | region by functional ink. Explanatory drawing which shows a mode that the display body of FIG. 20 was observed on conditions other than normal illumination conditions. The top view which shows the structural example of a latent image pattern. Explanatory drawing which shows a mode that the latent image pattern of FIG. 22 was tilted and observed. The perspective view which shows an example of the reflection preventing structure which is a structure employable as the 2nd area | region of a display body. The perspective view which shows an example of the light-scattering structure which is a structure employable as the 2nd area | region of a display body. 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 IV-IV line of the labeled article | item 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. 2 is a cross-sectional view taken along the line II-II of the display shown in FIG. The display body 1 includes a laminate of a print layer 10, a light transmission layer 11, and a light reflection layer 12. In this example, the light transmission layer 11 is an uneven structure forming layer. In the example shown in FIG. 2, the printed layer 10 side is the front side (observer side), and the light reflecting layer 12 side is the back side.
The printing layer 10 may be provided on the surface opposite to the surface on which the light transmitting layer 11 of the light transmitting base material 111 is provided as shown in FIG. 2, or as shown in FIG. The light reflection layer 11 may be provided between the light reflection layer 12 and the light reflection layer 12 as shown in FIG. Moreover, the light reflection layer 12 may not be provided partially.

  1, 2, 3, and 4, the display 1 includes a plurality of protrusions whose top surface is substantially parallel to the substrate surface, or a bottom surface that is the substrate surface. And at least one first region configured by arranging a plurality of recesses substantially parallel to each other and a flat portion substantially parallel to the substrate surface. In these drawings, a print area 13 is an area where a display image such as a character, a pattern, or a symbol is formed by the print layer 10, and a first area 14 is an area where minute irregularities are formed. The region 15 is defined as a region that is different in structure and optical properties from the first region 14. The second region 15 may be a region where an uneven structure different from that of the first region 14 is formed, or may be a region formed of a flat surface where no structure is formed. In addition, at least one or more first regions 14 are present in the display body 1, but a plurality of second regions 15 may be present in the display body 1 or none may be present. . A plurality of regions having different structures may be combined to form a display body.

  The printing layer 10 displays images such as characters, patterns and symbols, and various inks such as offset ink, letterpress ink and gravure ink are used depending on the printing method of the printing layer 10. The ink used for printing can be classified according to the composition such as resin type ink, oil-based ink, water-based ink, etc., and can be classified according to the drying method such as oxidation polymerization type ink, permeation drying type ink, evaporation drying type ink, ultraviolet curable ink, etc. It is appropriately selected according to the type of material and the printing method. In addition, toner with colored particles such as graphite and pigment adhered to plastic particles with chargeability is transferred to a substrate such as polyethylene terephthalate (PET) film or paper using static electricity, and then heated and fixed. A technique for forming a printed layer is also common.

  As shown in the cross-sectional view of FIG. 3, in the case where the printing layer 10 is provided between the light transmissive resin layer 112 and the light reflective layer 12 where the concavo-convex structure is formed, the light transmissive resin layer 112 is formed. It is desirable to form the printing layer 10 using a material having a refractive index close to that of the material. As a result, even in a region where the concavo-convex structure is already formed in the concavo-convex structure forming layer, the structure of the concavo-convex structure forming layer is smoothed by providing the printing layer 10 so as to fill the structure later, and the concavo-convex structure exists. Can be perceived as not. That is, the region where the uneven structure is provided in advance can be arbitrarily set as the print region 13 by providing the print layer 10.

  As shown in the cross-sectional view of FIG. 4, in the case where the printing layer 10 is provided on the light reflecting layer 12 on the side opposite to the surface in contact with the light transmissive resin layer 112 on which the concavo-convex structure is formed, the light reflecting layer 10 Is not provided on the entire surface, but is provided partially so that the printed layer 10 can be observed on the observer side.

  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, the light transmission layer 11 having a convex portion or a concave portion provided on one main surface is transferred from a metal stamper having a convex portion or a concave portion of the display body. Can be molded.

  2, 3, and 4, as an example, the light transmissive layer 11 configured by a laminated body of a light transmissive base material 111 and a light transmissive resin layer 112 is depicted. The light-transmitting substrate 111 is a film or sheet that can be handled by itself, and for example, PET, polycarbonate (PC), or the like can be used. The light transmissive resin layer 112 is a layer formed on the light transmissive substrate 111. The light transmitting layer 11 shown in FIGS. 2, 3 and 4 is formed by applying a thermoplastic resin or a photocurable resin on a light transmitting base material 111 and pressing a stamper on the coating film, for example. Is obtained by curing.

  As the light reflection layer 12, 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 light reflection layer 12. Alternatively, as the light reflecting layer 12, a laminate of dielectric layers having different refractive indexes between adjacent ones, that is, a dielectric multilayer film may be used. Of the dielectric layers included in the dielectric multilayer film, those in contact with the light transmission layer 11 desirably have a refractive index different from that of the light transmission layer 11. The light reflecting layer 12 can be formed by, for example, a vapor deposition method such as a vacuum evaporation method or a sputtering method.

  As a method of not providing the light reflecting layer partially, after providing the light reflecting layer by a vapor deposition method, only a specific part is dissolved by a chemical or the like, or the light reflecting layer and the light transmitting resin are dissolved. There is a method of peeling a light reflecting layer of a specific portion with an adhesive material having an adhesive strength stronger than the adhesive strength with the layer. In addition, a method of preventing a light reflection layer from being formed by providing a barrier on the front surface of the light transmissive resin layer before performing the vapor deposition method is also used.

  The display body 1 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 light reflecting layer 12. When the printing layer 10 is provided on the back side of the light reflecting layer 12, it is provided so as to cover the printing layer 10. When the display body 1 includes both the light transmission layer 11 and the reflection layer 12, the shape of the surface of the light reflection layer 12 is generally almost the same as the shape of the interface between the light transmission layer 11 and the light reflection layer 12. When the adhesive layer is provided, it is possible to prevent the surface of the light reflecting layer 12 from being exposed, so that it is difficult to duplicate the uneven structure at the previous interface for the purpose of counterfeiting. In addition, the resin layer is, for example, a hard coat layer intended to prevent the display surface from being scratched during use, an antifouling layer that suppresses adhesion of dirt, and reflection of light on the substrate surface For example, an antireflection layer or an antistatic layer.

  When the light transmitting layer 11 side is the back side and the light reflecting layer 12 side is the front side, the adhesive layer is formed on the light transmitting layer 11.

  The resin layer is provided on the front side with respect to the laminate of the light transmission layer 11 and the light reflection layer 12. For example, when the light transmission layer 11 side is the back side and the light reflection layer 12 side is the front side, the light reflection layer 12 can be prevented from being damaged by covering the light reflection layer 12 with a resin layer. In addition, it is possible to make it difficult to duplicate the uneven structure on the surface for the purpose of counterfeiting.

(Description of the first area)
In describing the first region according to the present invention, first, the relationship between the pitch of the diffraction grating and the wavelength of the illumination light, and the illumination light incident angle and the emission angle of the diffracted light will be described.

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

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

d = mλ / (sin α−sin β) (Formula 1)

  In Equation 1, d represents the grating constant (grating period, pitch) of the diffraction grating, m represents the diffraction order, and λ represents the wavelength of incident light and diffracted light. Α represents the exit angle of the 0th-order diffracted light, that is, 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 line NL.

  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.

  FIG. 5 shows the relationship between the illumination light incident angle and the emission angle of the + 1st order diffracted light with respect to the diffraction grating having the pitch d. When the illumination light is white light including a plurality of wavelength components, the exit angle of the diffracted light varies depending on the wavelength. As a result, when the diffraction grating is observed under a white illumination light source such as the sun or a fluorescent lamp, white light is dispersed, and light of a single wavelength is emitted at different angles. In FIG. 5, white light IL (here, it is assumed that the wavelength components constituting white light are three wavelengths of R, G, and B) are incident from the point light source LS, and the diffracted light of the wavelength component R by the diffraction grating GR. It shows a state where light is split into DL_r, diffracted light DL_g of wavelength component G, and diffracted light DL_b of wavelength component B. At this time, the exit angle β_r of the diffracted light of the wavelength component R, the exit angle β_g of the diffracted light of the wavelength component R, and the exit angle β_b of the diffracted light of the wavelength component R take different values for each wavelength (in FIG. , Only the exit angle of DL_r is described as β_r). Other orders of diffracted light are also emitted at angles derived from Equation 1, but are not shown in FIG.

  FIG. 6 is a diagram schematically showing a state in which the display body of the present invention emits + 1st order diffracted light. When white light is incident on a diffraction grating having a wider pitch than that in FIG. A state of injection is schematically shown. When the pitch d is large, as is clear from Equation 1, the diffracted light is emitted in a direction closer to the specularly reflected light RL as compared with the diffraction grating having a narrow pitch, and the emission angles of the separated single-wavelength light beams. The difference between is small. As apparent from Equation 1, when the diffraction grating is in a medium having a constant refractive index distribution (for example, in the air), the exit angle of the diffracted light is the incident angle and wavelength of the incident illumination light, and the pitch of the diffraction grating. Uniquely determined by

  Next, the relationship between the pitch of the diffraction grating and the wavelength of the illumination light and the intensity (diffraction efficiency) of the diffracted light in the direction of the emission angle of the diffracted light will be described.

Illumination light that is incident on the diffraction grating of pitch d at an incident angle of α emits diffracted light in the direction of angle β based on Equation 1. At this time, the emission intensity of the light having the wavelength λ, that is, the diffraction efficiency, varies depending on the pitch and height of the diffraction grating and is derived by Equation 2.

  Here, η is the diffraction efficiency (having a value of 0 to 1), r is the height of the diffraction grating, L is the grating line width of the diffraction grating, d is the pitch of the grating line, θ is the incident angle of the illumination light, λ Is the wavelength of incident light and diffracted light. Note that Equation 2 holds for a shallow rectangular diffraction grating having a concavo-convex structure.

  As is apparent from Equation 2, the diffraction efficiency varies depending on the height r of the diffraction grating, the pitch d of the grating lines, the incident angle θ of incident light, and the wavelength λ. In practice, the diffraction efficiency tends to gradually decrease as the diffraction order m becomes higher.

  Next, the structure and optical properties of the first region will be described.

In the first region, a plurality of convex portions whose upper surface is substantially parallel to the base material surface or a plurality of concave portions whose bottom surface is substantially parallel to the base material surface, and a flat portion substantially parallel to the base material surface are arranged. The plurality of convex portions or concave portions have a long side and a short side length of 0.3 μm or more and 10 μm or less, respectively, and the height of the convex portion or the concave portion is 0.1 μm or more. And the convex portions or concave portions are arranged in an orderly or non-ordered manner, and the area occupied by the convex portions or concave portions in the region is 20% or more and 80% or less.
Here, the longest part of a convex part or a recessed part is defined as a long side, and the shortest part is defined as a short side. In other words, the convex portion or the concave portion has a shape enclosed in a rectangle having sides of 0.3 μm or more and 10 μm or less. For example, when the convex portion has a perfect circle shape, the long side and the short side have the same value. In the case of an ellipse or a rectangle, the long axis side is the long side and the short axis side is the short side.

  FIG. 7 is a plan view showing an example of a structure that can be employed in the first region of the display body of the present invention, and is a partially enlarged plan view of the first region 14 provided on the display body 1 of FIG. It is. FIG. 8 is a sectional view taken along line III-III in FIG. The circular convex portions 16 are regularly arranged in a predetermined direction (A, B, and C indicated by a one-dot chain line) in the first region 14.

  Note that the above-described orderly arrangement means that the convex portions or the convex portions are arranged at equal intervals or regularity, for example, a square lattice, a rectangular lattice, or a triangular lattice. By controlling the arrangement of these concave portions or convex portions, there is an advantage that diffracted light with less stray light can be obtained.

  FIG. 9 is a plan view showing an example of another structure that can be employed in the first region of the display body of the present invention. The first region 14 provided on the display body 1 in FIG. 1 is partially enlarged. It is a top view. The rectangular projections 16 are formed in an unordered arrangement (random arrangement) in the first region 14. When the convex portions or the concave portions are arranged non-orderly, as shown in FIG. 9, the convex portions or the concave portions may be formed so as to overlap each other.

  As another example of the shape of the convex portion or the concave portion, an elliptical shape, an octagonal shape, a star shape, a polygonal shape such as a cross, etc. can be arbitrarily adopted. Moreover, the convex part or recessed part from which a shape differs may be mixed in the 1st area | region.

  FIG. 10 is a schematic view showing a state of diffracted light emitted from the diffraction grating. In the diffraction grating GR composed of a plurality of grating lines regularly formed in the direction parallel to the y-axis as shown in FIG. 10, when the illumination light IL is incident, the y-axis (longitudinal direction of the grating lines) Diffracted beams DL_r, DL_g, and DL_b are emitted in the orthogonal direction (x-axis direction).

  On the other hand, FIG. 11 is a schematic view showing the state of diffracted light emitted from a display body adopting the present invention. When illumination light enters the structure as shown in FIG. Diffracted light is emitted by the concavo-convex structure with periodicity formed by the plurality of convex portions 16 and the surrounding flat portions 17. As shown in FIG. 7, in the structure in which the convex portions 16 are regularly arranged in the first region 14 so as to be spaced apart from each other, the diffracted light is not limited to the x-axis direction but is diffracted with respect to many azimuth angles on the XY plane. It is injected. The diffracted light emitted here is diffracted light DL_r having a long wavelength on the side closer to the incident light, as in the case where the light is incident on the diffraction grating as shown in FIG. DL_g and further DL_b are emitted in the direction of moving away. Although FIG. 11 illustrates a state in which light is incident on one point in the first region, in reality, light is incident on the first region in a planar shape, not incident on one point.

The plurality of convex portions 16 are regularly arranged in the first region 14 so as not to contact each other. In FIG. 7, the diameter of the convex part 16 shall be about 1 micrometer. Here, considering the direction indicated by the one-dot chain line A and one-dot chain line B in FIG. 7, it can be considered that a diffraction structure having a pitch of about 1.4 μm is formed by the plurality of convex portions 16. Here, assuming that the white illumination light source is provided vertically above the display body, and the white illumination light is incident on the surface of the display body from the vertical (incident angle α = 0 °) direction, for example, white Of the illumination light, light having a wavelength of 630 nm is emitted as + 1st order diffracted light at an angle β≈26.7 ° according to Equation 1. Further, light having a wavelength of 540 nm has an angle of 22.7 °, and light having a wavelength of 460 nm has an angle of 19.2 °. Also in other directions (for example, the alternate long and short dash line C), diffracted light is emitted based on Equation 1 due to the periodicity of the plurality of convex portions 16. In general, since an illumination light source such as the sun or a fluorescent lamp has a certain area, light is incident on the diffractive structure from an oblique direction. For example, if light from a white illumination light source enters the diffraction structure from an angle of α = 1.0 °, the + 1st order diffracted light has an angle β≈25.7 ° of light with a wavelength of 630 nm and an angle β of light with a wavelength of 540 nm. Light having a wavelength of approximately 21.6 ° and a wavelength of 460 nm is emitted in the direction of an angle β≈18.2 °.
In other words, since the illumination light source that is actually the incident light usually has a certain area, the light observed by the observer at a fixed point is a combination of light of a certain range of wavelengths, and as a result, light of multiple wavelengths. The color due to will be observed.

  Even in a structure in which a plurality of convex portions 16 are arranged in an unordered manner as shown in FIG. 9, diffracted light is emitted. In the case as shown in FIG. 9, the value of d shown in Equation 1 varies, so the exit angle of the diffracted light varies depending on the location. For this reason, the wavelength component of the diffracted light reaching the fixed point is in a wider range than the structure shown in FIG. 7, and the color due to light having more wavelengths is observed.

  In this way, the conditions under which the light from the illumination light source is incident on the surface of the display body, the incident light is diffracted by the concavo-convex structure forming layer of the display body, and the observer can perceive the light visually are referred to as `` normal illumination conditions It is defined as “below”. For example, in a general room, the light from the illumination light is incident on the surface of the display body substantially perpendicularly to the display body under illumination light such as a fluorescent lamp, and the condition for the observer to observe the display body visually, The condition under which the light from the illumination light is incident on the surface of the display body under illumination light such as sunlight outside the room substantially vertically and the observer observes the display body is `` normal illumination conditions Is equivalent to. Here, “normal illumination light” refers to illumination light such as an indoor fluorescent lamp or outdoor sunlight.

  “Conditions other than normal illumination conditions” indicate conditions under which the observer cannot perceive diffracted light. For example, the condition that the light from the illumination light is incident on the surface of the display body substantially horizontally, that is, at a steep angle, and the diffracted light is not emitted from the uneven structure forming layer of the display body, or the uneven structure forming layer of the display body Even if the diffracted light is emitted from, the condition that the observer views the display body from an angle at which the diffracted light does not reach corresponds to “a condition other than normal illumination conditions”.

  In order to obtain a structure in which a color composed of light of a plurality of wavelengths can be observed, it is better to use a slightly larger structure of about 5 to 10 μm in the case of an ordered arrangement. In the case of a large structure, since the difference in the exit angle of the diffracted light with respect to each wavelength is small as apparent from Equation 1, even if the position of the illumination light source or the observer changes, the display color does not change to a so-called rainbow color. Colors with multiple wavelengths can be observed stably.

  On the other hand, when arranging non-orderly, a convex part or a recessed part can be made into a slightly smaller structure of about 0.3-5 micrometers. When a small structure is formed with a small arrangement interval, the emission angle of the diffracted light becomes large as apparent from Equation 1. For this reason, in the structure arranged in an orderly manner, it is easy to change the color to iridescent, but by arranging it in an unordered manner, light of a plurality of wavelengths can easily reach a fixed point where the observer is present. In addition, when the small structures are arranged in an unordered manner, the emission angle of the diffracted light becomes large, so that there is an advantage that display colors by a plurality of lights can be observed in a wide range.

Here, as shown in Expression 2, the amount of light of the diffracted light emitted from the diffractive structure, that is, the diffraction efficiency changes according to the wavelength. In particular, assuming that the grating line width L of the diffraction grating and the pitch d of the grating line are constant, the diffraction efficiency η corresponds to the height r of the diffraction grating (corresponding to the height of the convex part or the depth of the concave part) and the illumination light. Is uniquely determined by the wavelength λ.
For this reason, when the display body (first region) is observed from a fixed point, the wavelength component of visible light does not reach the eyes evenly, and the height of the convex portion provided in the first region (or the depth of the concave portion). The diffraction efficiency of light having a specific wavelength is reduced according to the above, and as a result, the light reaching the observer becomes light in which the specific wavelength component of the incident white illumination light is weakened. Therefore, when the observer observes the first region, he / she perceives light having a plurality of wavelengths having different light amounts. For each of the plurality of first regions provided on the display body, a different color is displayed when the respective regions are observed by forming convex portions (or concave portions) at different heights (or depths). It becomes possible.

  For example, when observing a first region provided with a convex portion of a certain height, the diffraction efficiency of blue (wavelength 460 nm) light becomes weak, and the wavelength component of diffracted light reaching the eyes of the observer is red. (Wavelength 630 nm) and green (wavelength 540 nm), the observed color is yellow, and the red wavelength when observing another first region provided with a convex portion of another height If the diffraction efficiency of the component light is weakened and the wavelength components of the diffracted light reaching the eyes of the observer are green and blue, the observed color is cyan (light blue).

  These colors cannot be observed when the observer is at a position where the diffracted light does not reach. Thereby, unlike a normal printed matter, two states can be realized: a state where the display color can be perceived and a state where the display color cannot be perceived depending on the position of the illumination light source or the observer. This is different from ordinary printed matter in which almost the same color can be perceived in many ranges.

  In the conventional display device using a diffraction grating for the purpose of preventing forgery, the processing accuracy of the diffraction grating is not sufficient, and it does not have an ideal rectangular cross-sectional shape as shown in FIGS. In general, the cross-sectional shape is sinusoidal as shown in the cross-sectional view of FIG. 12, or the top portion or the flat portion of the convex structure is bumpy as shown in the cross-sectional view of FIG. Therefore, it becomes difficult for the diffraction efficiency to change according to the height (depth) of the structure for each wavelength as shown in Equation 2. In other words, since the difference in the diffraction efficiency of each wavelength is reduced, the light reaching the fixed point where the observer is located reaches all the wavelengths of light emitted from the white illumination light source, and the observer reaches The perceivable color is close to white and it becomes difficult to display a highly saturated color. For example, when white illumination light is incident on a minute concavo-convex structure such as a so-called frosted glass, which is not uniform in height and shape, the light is scattered and perceived as white.

  On the other hand, in the structure adopted in the first region of the present invention, the height of the convex portion (or the depth of the concave portion) is substantially the same in one first region and is substantially parallel to the substrate surface. Therefore, since it has an effect of preventing the diffraction efficiency of light of a specific wavelength from being lowered and reducing the diffraction efficiency of light of another specific wavelength, it is possible to display a highly saturated color.

  Further, the structure employed in the first region of the present invention emits diffracted light with respect to many azimuth angles on the XY plane as shown in FIG. Even if it changes, a color composed of a plurality of wavelengths can be observed. For this reason, it is possible to avoid or reduce the phenomenon that the display color changes to iridescent as in the conventional diffraction grating.

  In addition, although the convex part or the recessed part is arranged in multiple numbers, the structure arranged regularly regularly may be sufficient, and may be arranged irregularly irregularly.

(Structures and effects that can be used in the first area)
The first region is provided in at least a part of the uneven structure forming layer of the display body. FIG. 14 is a diagram illustrating an arrangement example of the first area and the second area on the surface of the display body. 14 shows a first region 14 (a region shown in the upper left of FIG. 14) composed of a plurality of convex portions arranged in an orderly manner and a first region 14 (a lower right portion composed of a plurality of convex portions arranged in an orderly manner). ), The second region 15 (region shown in the lower left) where the diffraction grating 18 is formed, and the second region 15 (region shown in the upper right) where the antireflection structure 19 is formed. It is an example in which the uneven structure forming layer of the display body is configured.

  As shown in FIG. 14, the display body may have a plurality of first regions, and separate structures may be formed, or the same convex portion (or concave portion) is changed only in height (depth). It may be provided in a state. Also in the second region, a plurality of separate structures may be formed, or the same structure may be provided. By making the height of the convex part (the depth of the concave part) constant within one first region, the observer has diffracted light with a plurality of wavelengths such that the region is perceived with a predetermined color. Can be injected to a fixed point. By forming a structure having a height (depth) different from that in another first region, the region can display a color of a different hue. Note that the first area and the second area arranged on the surface of the display body are conceptual, and the actual display body does not have a boundary by a visible boundary line as shown in FIG.

  By dividing the surface of the display body into a plurality of first regions and displaying colors of different hues, images such as characters and designs can be expressed. As the shape and arrangement method of the first area, a method of arranging rectangles such as squares and rectangles and parallelograms such as parallelograms in a matrix form, or hexagons and triangles are spread over the display body surface. It is possible to adopt a method of arranging them closely. FIG. 15 shows an example in which a plurality of first regions each having a rectangular shape are arranged in a matrix. FIG. 16 is an example in which hexagonal first regions are arranged in a close-packed manner. By regularly arranging the first regions having such a shape, an image having a pixel structure can be expressed. A plurality of first regions may be provided with different arrangement rules inside one display body. Further, the first area may be an area having an indefinite shape as shown in FIG.

  The length of one side of the first region is preferably 300 μm or less. By arranging the first regions with a side length of 300 μm or less in order, the shape of each first region can be prevented from being recognized when the display body is observed with the naked eye, and the resolution can be reduced. A high-definition image can be expressed. Here, the one side of the first region indicates the side of the maximum length of the first region.

  The lengths of the long side and the short side of the convex portion or the concave portion that can be employed in the first region are 0.3 μm or more and 10 μm or less, respectively. Visible light can be sufficiently diffracted if the structure has a size in this range. When it is smaller than 0.3 μm, processing becomes difficult and it becomes difficult to emit visible light, so that it easily functions as an antireflection structure. On the other hand, if it is larger than 10 μm, it becomes difficult to diffract, and at the same time, diffracted light is emitted near the direction in which the illumination light is incident.

  Moreover, it is preferable that the occupied area of the convex part or the concave part in the first region is 20% or more and 80% or less. From Equation 2, the diffraction efficiency η is highest when the width of the convex or concave portion (corresponding to the lattice line width L of Equation 2) is half of the pitch d. Therefore, the brightest display image can be obtained when the area occupied by the convex portion or the concave portion is about 50%, and it is most desirable. If it is about 20% or more and 80% or less, the diffraction efficiency decreases as the distance from 50% increases. Although the image becomes dark, it is possible to visually recognize a display image composed of light of a plurality of wavelengths. Note that the diffraction efficiency when the occupied area is 20% and 80% is about 30% of the brightness of 50% from Equation 2.

  If the area occupied by the protrusions or recesses is less than 20% or greater than 80%, sufficient brightness cannot be obtained, and it becomes difficult to obtain a sufficient eye-catching effect.

  Moreover, it is preferable that the height of a convex part or the depth of a recessed part is the range of 0.1 micrometer or more and 0.5 micrometer or less. In Formula 2, assuming that the pitch d and the grating line width L are constant, when the light having a wavelength in the visible light range is incident at an incident angle θ (a range greater than 0 ° and less than 90 °), the diffraction efficiency is highest. The height of the convex portion or the depth value of the concave portion is in the range of 0.1 μm to 0.5 μm. Note that, from Equation 2, the conditions for the highest diffraction efficiency are repeated even when the diffraction efficiency is larger than that, but for manufacturing, it is easier to manufacture when the height of the convex portion or the depth of the concave portion is as shallow as possible. Therefore, the conditions of 0.1 μm or more and 0.5 μm or less that can obtain high diffraction efficiency at a shallower value are desirable.

  In addition, when the height of the convex part or the depth of the concave part is less than 0.1 μm, the same quality is stable due to external factors during manufacturing (variation in machine and environmental conditions, slight changes in material composition, etc.) It is difficult to fabricate the product, and when it is deeper than 0.5 μm, it becomes difficult to precisely transfer and mold a fine and deep structure.

(Visual effect by the first area and the print area)
The display body has a printing layer. The print layer is made of ink or toner, and develops the hue, lightness, and saturation that are unique to the ink and toner, and the hue changes greatly depending on the incident angle of the illumination light and the observation angle of the observer. Absent. On the other hand, the first region can display a unique color under normal illumination conditions, and can exhibit a color change when the conditions change. Since these two layers having different functions are formed in the display body, it is possible to provide a specific visual effect that cannot be realized only by a normal printing layer. Therefore, the display body and the article supporting the display body can realize a high anti-counterfeit effect.

  The ink or toner forming the printing layer is appropriately selected in material, density, printing method, etc., and has substantially the same hue, brightness, and color as those perceived when the first region is observed under normal illumination conditions. It is preferable that the color has a degree. As a result, both are perceived as substantially the same color under normal lighting conditions, making it difficult to distinguish between the differences in configuration. In addition, by observing the display body under conditions that do not allow diffracted light to be observed by tilting the display body or deviating from normal lighting conditions, color display by the print area where hue, brightness, and saturation do not change much, and hue The color display by the first region where the brightness and the saturation change is separated, so that the difference between the two configurations can be discriminated.

  For example, in the example shown in FIG. 18, the entire surface of the display body 1 is perceived as a rectangle of the same color under normal illumination conditions, but when the display body 1 is observed by tilting the display body 1 as shown in FIG. In addition, the display can be divided into a character portion formed by the first region 14 and a background portion formed by the print region 13, and an effect that information that cannot be recognized under normal lighting conditions can be obtained.

  As the printing ink, a functional ink whose color changes according to the wavelength of the light source to be used or the angle to be observed can be used. Examples of the ink whose color changes depending on the wavelength of the light source used include fluorescent ink and phosphorescent ink. In addition, examples of the functional ink whose color changes according to the observation angle include optical change ink (Optical Variable Ink), color shift ink, pearl ink, and retroreflective ink.

  The fluorescent ink is an ink containing a fluorescent pigment, has a function of displaying a unique color when irradiated with ultraviolet rays, and the phosphorescent ink has a function of emitting light when the illumination becomes dark. Optical change ink and color shift ink have a function of causing a color change from red to green or from blue to purple, for example, depending on the viewing angle, and pearl ink has a specific angle. On the other hand, it has the function of producing a pale pearl tone color. The retroreflective ink has a function of strongly reflecting light from the illumination light source at an angle close to the incident angle of the illumination light. By using such a functional ink, it is possible to realize a color change corresponding to a change in observation conditions in both the first region and the print region. By providing multiple structures that cause color changes in the display body, even those who are not familiar with the act of making an authenticity judgment by tilting the display body can easily recognize the color change, and more reliably authenticate Judgment can be made. In particular, it is possible to observe both color changes at the same time by making the angle at which the color change occurs due to the functional ink substantially coincide with the angle at which the display color changes by the first region. It can be done reliably.

  When the display body has a printing area with functional ink, the counterfeit prevention effect is higher than that of a printing area with general ink or toner that does not exhibit a color change, and authenticity determination can be performed more reliably. In this case, as shown in FIG. 20, under normal lighting conditions, both the character portion by the first region 14 and the character portion by the printing region 13 are perceived in different colors, and under normal lighting conditions. In an environment other than the above, as shown in FIG. 21, both the character portion formed by the first region 14 and the character portion formed by the print region 13 change to different colors.

  Further, a latent image pattern is known as an image display technique that exhibits an anti-counterfeit effect. The latent image pattern is such that the display image is not recognized under normal illumination conditions, and the hidden display image can be recognized when the display body is tilted at a predetermined angle.

  As a configuration of the latent image pattern, as shown in FIG. 22, the concealed image 21 and the peripheral portion 22 of the concealed image are generally configured by thin lines orthogonal to each other. The distance between the thin lines is about 3 to 10 per 1 mm, and an image having such a configuration is difficult to distinguish between vertical and horizontal lines that are orthogonal under normal illumination conditions, and it is difficult to recognize the image (FIG. 22). (The image can be recognized because the interval between the thin lines is wider than the actual one).

  When such a latent image pattern is observed at a predetermined angle as shown in FIG. 23, the interval between the vertical line of the concealed image and the horizontal line of the peripheral part of the concealed image appears to change. The hidden image can be observed.

  The first area can display a unique color under normal illumination conditions, and can exhibit a color change when the conditions change, so by providing a latent image pattern in the print area, the first area Therefore, it is possible to achieve both the color change due to the color change and the display image change due to the print area, and a higher forgery prevention effect can be obtained.

  Further, for example, a latent image pattern can be realized by forming a concealed image as a print region by printing and forming a peripheral portion of the concealed image as a first region with a concavo-convex structure. In that case, the concealed image is difficult to be recognized under normal lighting conditions, and when the conditions change, the concealment is more clearly concealed by the effects of both the color change in the first region and the change in the distance between the vertical and horizontal lines. The image becomes easy to recognize.

(Explanation of the second area)
Next, the second area will be described.
The second region 15 is a region that differs in structure and optical properties from the first region 14. The second region 15 may have a concavo-convex structure different from that of the first region 14, or may be a flat surface on which no structure is formed. A plurality of second regions 15 may exist in the display body 1.

  An example of a structure that can be used for the second region 15 is a diffraction grating. The diffraction grating is typically formed by repeatedly forming a linear concavo-convex structure (grating line) as shown in the perspective view of FIG. 10, with a pitch of about 0.5 to 1 μm and a structure height of 0. A typical specification is about 1 to 0.5 μm. The diffraction grating emits a rainbow-colored spectral color due to diffraction, and displays an image that changes in color and pattern according to the observation conditions such as the position of the light source and the observation angle of the observer, or displays a three-dimensional image Can do.

  Another structure that can be adopted for the second region 15 is an antireflection structure having a fine concavo-convex structure. The antireflection structure is typically a conical structure 19 as shown in the perspective view of FIG. 24 or a structure in which pyramidal structures are regularly arranged, and the structure has a wavelength less than the wavelength of visible light (for example, It is arranged with a pitch of 400 nm or less, and the higher the structure height is 300 μm or more, the higher the antireflection function is. The antireflection structure formed according to the specifications as described above has a function of preventing or reducing reflection of incident visible light, and looks black or dark gray when observed.

  Further, as a structure that can be employed in the second region 15, a light scattering structure can be cited. As shown in the perspective view of FIG. 25, the light scattering structure is typically one in which a plurality of irregular shapes 20 having different sizes, shapes, and structure heights are irregularly arranged. The light incident on the light scattering structure is irregularly reflected in all directions and appears white or cloudy when observed. Typically, many light scattering structures have a width of 3 μm or more and a height of 1 μm or more, and have a larger structure than a diffraction grating or an antireflection structure. Moreover, the size, arrangement interval, and shape are not uniform. Therefore, it is difficult for light to be diffracted or absorbed, and an effect of scattering light can be obtained.

  Further, the second region 15 may be a flat surface on which no concavo-convex structure is formed. When the second region 15 is a flat surface, the second region 15 looks like a mirror surface by the light reflecting layer 13.

  By combining the second region 15 and the first region 14, the design of the display body can be improved, and the effect of preventing forgery can be further improved. In the second region, a structure other than the above-described structure that exhibits optical characteristics different from those of the first region may be formed.

(How to use the display)
The display body 1 described above can be used, for example, by sticking it to a printed matter or an article outside it through an adhesive or the like as an anti-counterfeit label. The display body 1 can display colors of a plurality of wavelengths by a fine uneven structure, and forgery is difficult because the color changes by changing the height of the structure. When this label is supported on an article, it is also difficult to forge or imitate the genuine article with label.

  FIG. 26 is a plan view schematically showing an example of a labeled article in which an anti-counterfeit label is supported on the article. 27 is a cross-sectional view of the labeled article shown in FIG. 26 taken along line IV-IV.

  26 and 27, a printed matter 100 is illustrated as an example of a labeled article. This printed material 100 is an IC (integrated circuit) card and includes a base material 50. The base material 50 is made of plastic, for example. A concave portion is provided on one main surface of the substrate 50, and the IC chip 30 is fitted in 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 50. 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 the display body 1. Therefore, it is difficult to counterfeit or imitate the same printed product 100. In addition, since the printed material 100 further includes the IC chip 30 and the printed layer 40 in addition to the display body 1, it is possible to adopt measures for preventing forgery using them.

  26 and 27 illustrate an IC card as a printed material including the display body 1, the printed material including the display body 1 is not limited to this. For example, the printed matter including the display body 1 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 1 may be securities such as gift certificates and stock certificates. Alternatively, the printed matter including the display body 1 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 1 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.26 and FIG.27, although the display body 1 is affixed on the base material 50, the display body 1 can be supported on a base material by another method. For example, when paper is used as the base material, the display body 1 may be rolled into the paper and the paper may be opened at a position corresponding to the display body 1. Alternatively, when a light-transmitting material is used as the base material, the display body 1 may be embedded therein, or the display body 1 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 1 may be supported on an article that does not include a printed layer. For example, the display body 1 may be supported by a luxury product such as a work of art.

  The display body 1 may be used for purposes other than forgery prevention. For example, the display body 1 can be used as a toy, a learning material, or a decoration.

(Preparation method of display plate)
Next, a method for producing the original plate of the display body of the present invention will be described.

  The original plate of the display body of the present invention can be produced by using a photolithography process in the same manner as a conventional relief diffraction grating production process. By exposing and developing a photosensitive resist applied substantially uniformly on a planar substrate (a glass substrate is generally used) by a charged particle beam such as an electron beam or a laser, a desired uneven shape is obtained. If the photosensitive resist is a positive resist, the portion irradiated with the charged particle beam dissolves after development, and if the photosensitive resist is a negative resist, the portion irradiated with the charged particle beam is developed after development. The remaining unirradiated part dissolves. The substrate is placed on an XY stage whose position can be adjusted with high accuracy, and the position where the charged particle beam is irradiated is determined while moving the stage under computer control.

  The substrate thus obtained has a concavo-convex structure made of a photosensitive resist and is not suitable as a stamper for mass production. Therefore, a metal stamper is produced from the substrate by using a method such as electroforming. . Electroforming is a type of surface treatment technology that forms a metal film by reducing the power of electrons by immersing an electroformed object in a predetermined aqueous solution and energizing it. By using such a method, The fine concavo-convex structure provided on the surface of the original plate can be transferred and molded as a metal plate with high accuracy. The surface of the object of electroforming needs to be able to be energized. Generally, the photosensitive resist does not conduct electricity. Therefore, before electroforming, metal is deposited on the surface of the structure by vapor deposition such as sputtering or vacuum evaporation. A thin film is provided in advance.

  Next, the concavo-convex structure is duplicated using this metal stamper as a matrix. That is, first, a thermoplastic resin or a photocurable resin is applied on a transparent substrate made of, for example, polycarbonate or polyester. Next, a metal stamper is brought into close contact with the coating film, and heat or light is applied to the resin layer in this state. After the resin is cured, the concavo-convex structure can be replicated by peeling the metal stamper from the cured resin.

Generally, the base material and the resin material for formation are transparent. Therefore, normally, a reflective layer is formed on a resin layer (uneven structure forming layer) provided with an uneven structure by depositing a metal such as aluminum or a dielectric in a single layer or multiple layers by vapor deposition or the like.
Then, the display body obtained in this way is affixed on the base material which consists of paper or a plastic film through an adhesive layer or an adhesion layer, for example. As described above, a display body with anti-counterfeit measures is obtained.

  As a method for producing the original plate, not only a photolithography process but also a process using a cutting tool such as a diamond tool having a fine tip, a process of corroding the surface of a metal or the like by etching, or the like can be employed. When such a method is used, it is possible to directly process the surface of the metal plate. In this case, the metal stamper can be obtained directly without creating a metal stamper by a method such as electroforming.

  In a method of processing a concavo-convex shape by irradiating a photosensitive resist coated on a substrate with a charged particle beam, a phenomenon called a proximity effect occurs. The proximity effect is a phenomenon in which the size and depth of the shape slightly change from the target size and depth depending on the size of the uneven shape to be processed and the ratio of the area irradiated with the beam per unit area. That is. For example, even if a 0.5 mm square area is processed under the condition that a concave structure having a 1 mm square area and a depth of 0.1 mm can be processed with a certain amount of energy, a depth of 0.1 mm cannot be obtained. It becomes a slightly shallower concave structure. This is due to the phenomenon that the charged particle beam is scattered in the resist. This phenomenon is roughly divided into a phenomenon called forward scattering and a phenomenon called back scattering. The forward scattering occurs when the charged particle beam enters the resist, and the charged particle beam spreads, and the charged particle beam affects the area larger than the irradiated area. On the other hand, backscattering affects the photosensitive resist by a charged particle beam that passes through the photosensitive resist and is reflected by the front surface or the back surface of the substrate on the lower surface of the photosensitive resist. The influence of these scattered beams varies depending on the energy amount of the beam, the shape and depth of the pattern to be processed. The influence of the proximity effect also varies depending on the material composition of the photosensitive resist used and the applied film thickness.

  Therefore, when forming the convex portion or the concave portion provided in the first region on the original plate, the influence of the proximity effect changes depending on the area of the region, the size of the convex portion or the concave portion, the arrangement density, and the like. There is a possibility that a structure having a height (depth) may not be obtained. In the first area, the display color under normal illumination conditions is determined by the height (or depth) of the convex part (or concave part) provided in the first area, considering the influence of the proximity effect. It is necessary to process the structure with high accuracy.

  On the other hand, even if a third party uses a processing machine that uses a highly accurate charged particle beam, it is extremely difficult to forge an original plate having the same shape, and the same display color is obtained. It is difficult and the anti-counterfeiting effect is very high.

  As a processing machine using a charged particle beam, an electron beam drawing apparatus or a laser direct drawing apparatus is desirable. Since these apparatuses have a high processing speed and high position accuracy of the XY stage, it is possible to create a desired uneven pattern with high accuracy. Some have a function to make corrections based on experimental results so as to reduce the influence of the proximity effect. In order to obtain a desired display color, the structure employed in the first region needs to strictly control the height (depth), and these apparatuses can satisfy the requirement. Recent electron beam lithography equipment and laser direct lithography equipment have been improved in performance, and the stability of the charged particle beam to be radiated is high and the energy irradiation amount and energy density are almost the same with the same settings. There may be fluctuations due to slight changes in the usage environment (temperature, humidity, etc.) and the influence of device conditions (such as long-time operation). However, the amount of change is small, and when the same pattern is processed, the shape and depth of the processed pattern hardly change.

  On the other hand, it is possible to produce the original plate of the display body of this patent even by a method using processing or etching with a cutting device, but in that case, high processing accuracy is required, and selection of an appropriate material is important. . In addition to the fabrication of the structure of the first region, it is difficult to fabricate a diffraction grating that can be formed in the second region, an antireflection structure with a fine concavo-convex structure, a light scattering structure, etc. It is.

DESCRIPTION OF SYMBOLS 1 ... Display body, 10 ... Print layer, 11 ... Light transmission layer, 12 ... Light reflection layer, 13 ... Print area | region, 14 ... 1st area | region, 15 ... 2nd area | region, 16 ... Convex part, 17 ... Flat part , 18 ... diffraction grating, 19 ... antireflection structure, 20 ... light scattering structure, 21 ... concealed image, 22 ... peripheral part of concealed image, 30 ... IC chip, 40 ... printed layer, 50 ... substrate, 100 ... Printed material, 111 ... light-transmitting substrate, 112 ... light-transmitting resin layer, d ... diffraction grating pitch, DL ... + 1st order diffracted light, DL_r ... + 1st order diffracted light (red), DL_g ... + 1st order diffracted light (green), DL_b ... + 1st order diffracted light (blue), GR ... diffraction grating, IL ... illumination light, LS ... light source, NL ... normal, RL ... 0th order diffracted light (regularly reflected light), α ... incident angle, β ... exit angle, β_r ... Emission angle of diffracted light of wavelength component R, β_g ... Ejection angle of diffracted light of wavelength component G, β_b ... Wavelength component Emission angle of B diffracted light

Claims (7)

A light transmissive substrate;
A concavo-convex structure forming layer provided on one surface side of the substrate;
A light reflecting layer covering at least a part of the concavo-convex structure forming layer and a substrate surface opposite to a surface provided with the concavo-convex structure forming layer; and between the concavo-convex structure forming layer and the light reflecting layer, And a printed layer formed on one of the surfaces of the light reflecting layer opposite to the surface in contact with the concavo-convex structure forming layer,
A display body comprising
The concavo-convex structure forming layer includes a plurality of convex portions whose upper surface is substantially parallel to the base material surface, or a plurality of concave portions whose bottom surface is substantially parallel to the base material surface, and a flat portion substantially parallel to the base material surface. Comprising at least one first region configured by being arranged,
The plurality of convex portions or concave portions have a long side and a short side length of 0.3 μm or more and 10 μm or less,
The height of the convex part or the concave part is 0.1 μm or more and 0.5 μm or less,
The convex portion or the concave portion is arranged in an orderly or non-ordered manner in the first region,
The occupation area of the convex part or the concave part in the first region is 20% or more and 80% or less,
A display body characterized by being. In addition to displaying a display color having a predetermined hue by light composed of a combination of a plurality of visible light wavelengths under normal illumination conditions, the display color is not displayed under conditions other than normal illumination conditions.
The display body according to claim 1.   At least a part of the printed layer is formed of ink or toner that displays a color that is perceived as substantially the same color as the display color by the combination of the plurality of visible light wavelengths when observed under the normal illumination conditions. The display body according to claim 1, wherein the display body is a display body.   The display body according to claim 1, wherein at least a part of the print layer is formed of a functional ink having a different color depending on a light source or an observation angle.   The display body according to claim 1, wherein a latent image pattern in which a display image changes according to an observation angle is formed by the printing layer or the concavo-convex structure forming layer.   At least one of a diffraction grating, an antireflection structure, a light scattering structure, and a flat portion is formed in a second region that is different in structure and optical properties from the first region. Item 6. The display body according to any one of Items 1 to 5.   A labeled article comprising the display body according to claim 1 and an article supporting the display body.