JP5369479B2 - Display, adhesive label and transfer foil - Google Patents

Description

  The present invention relates to an optical technique applicable to a display body.

  It is desirable that authentication items such as cash cards, credit cards and passports, and securities such as gift certificates and stock certificates are difficult to counterfeit. Therefore, conventionally, a label that is difficult to counterfeit or imitation and is easy to distinguish from counterfeit or counterfeit is attached to such articles.

  In recent years, the distribution of counterfeit products has been regarded as a problem for items other than certified items and securities. Therefore, the opportunity to apply the above-described anti-counterfeiting technology with respect to certified articles and securities is increasing.

  As an example of this forgery prevention technique, a polarization latent image device in which a retardation layer is formed on a reflection layer has been proposed. When this device is observed through a polarizing film, it displays an image whose brightness changes continuously according to the angle formed by the polarizing axis of the polarizing film and the slow axis of the retardation layer.

As an application of this technique, for example, an optical component that can display a plurality of images in the same plane by forming a latent image in a line shape is disclosed (see Patent Documents 1 and 2). . However, when a plurality of overlapping latent images are recorded in the same plane, it is extremely difficult to visualize each of these latent images with an excellent contrast ratio.
Japanese Patent Laid-Open No. 8-15681 Japanese translation of PCT publication No. 2002-530687

  Accordingly, an object of the present invention is to provide a display body that can visualize a plurality of latent images recorded so as to overlap each other with an excellent contrast ratio.

According to the first aspect of the present invention, there is provided a retardation layer including first to fourth regions that are adjacent to each other in an in-plane direction and have different slow axis directions in the in-plane direction. In the in-plane direction of the layer, an angle formed by the first slow axis with respect to a third straight line parallel to the main surface of the retardation layer is defined as a first angle θ ₁ and an angle formed by the second slow axis Is the second angle θ ₂ , the angle formed by the third slow axis is the third angle θ _3, and the angle formed by the fourth slow axis is the fourth angle θ ₄ , the first angle θ ₁ , the second angle θ ₂ , the third angle θ _3, and the fourth angle θ ₄ are expressed by a relational expression θ ₂ = θ ₁ + 22.5 °,
θ ₃ = θ ₁ - 4 5 °, and θ ₄ = θ ₁ +67.5 °
In the retardation layer, a first image corresponding to the first area and the fourth area and a second image corresponding to the third area and the fourth area are recorded as latent images. The first image is a case where the retardation layer is observed through a polarizer, and an angle θ _p formed by a polarization axis of the polarizer with respect to the third line is
θ _p = 11.25 ° or θ _p = 56.25 °
The second image is a case where the retardation layer is observed through a polarizer, and an angle θ _p formed by the polarization axis of the polarizer with respect to the third line is
θ _p = 33.75 ° or θ _p = 78.75 °
Visualized when satisfying said to visualize the first and second images, display bodies, characterized in that it is used to determine the authentic and the counterfeit is provided.

  According to the present invention, a display body capable of visualizing a plurality of latent images recorded so as to overlap each other with an excellent contrast ratio is realized.

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

  FIG. 1 is a plan view schematically showing a display body according to one aspect of the present invention. 2 and 3 are plan views schematically showing a latent image recorded on the display body shown in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV of the display shown in FIG. The IV-IV line is parallel to the X direction shown in FIG.

  The display body 10 includes a base material 100 and a retardation layer 200 formed thereon. On the display body 10, at least two images, that is, a first image P1 and a second image P2 are recorded as latent images.

  As the substrate 100, a film or sheet that does not have birefringence is typically used. In this case, for example, a TAC (triacetyl cellulose) film, an acrylic film, a glass plate, or an unstretched PET (polyethylene terephthalate) film, a PP (polypropylene) film, or a PE (polyethylene) film is used as the substrate 100. Can do.

  The substrate 100 may have a uniform birefringence in the in-plane direction. In this case, for example, a uniaxially or biaxially stretched PET film, PP film, PE film, polycarbonate film, cellophane film, X-cut quartz plate or Y-cut quartz plate can be used as the substrate 100.

  The substrate 100 may be a polarizer. In this case, for example, as the base material 100, an absorption polarizer obtained by impregnating PVA (polyvinyl alcohol) with iodine or a dichroic dye and stretching and orientation, absorption obtained by orienting the dichroic dye on the orientation film Polarizers, reflective circular polarizers with cholesteric liquid crystal aligned on a substrate, reflective polarizers made by laminating birefringent multilayer films, prism polarizers formed into lenticular lenses with Brewster angles, A birefringent diffractive polarizer in which a refractive material is formed in a diffraction grating shape, or a diffractive polarizer in which a groove of a diffractive structure is formed deeply can be used. Other than these, any element that can separate or extract a polarized light component in a specific direction with respect to reflected light or transmitted light can be used.

  The base material 100 may be omitted. That is, the display body 10 may be composed of only the retardation layer 200.

  The retardation layer 200 includes at least four regions A1 to A4 that are adjacent to each other in the in-plane direction. The first area A1 is an area corresponding to a portion of the second image P2 that does not overlap the first image P1. The second area A2 is an area corresponding to a portion where neither the first image P1 nor the second image P2 is recorded. The third area A3 is an area corresponding to a portion of the first image P1 that does not overlap with the second image P2. The fourth area A4 is an area corresponding to a portion where the first image P1 and the second image P2 overlap.

  In the regions A1 to A4, the directions of the slow axes in the in-plane direction are different from each other. In this aspect, the slow axis and the first straight line of the third region A3 are divided with respect to the first straight line L1 that bisects the angle formed by the slow axis of the first region A1 and the slow axis of the second region A2. The angle formed by L1 is equal to the angle formed by the first straight line L1 and the slow axis of the fourth region A4 or an axis perpendicular thereto. In addition, the second axis L2 and the second straight line L2 of the second region A2 are compared with the second straight line L2 that bisects the angle formed by the slow axis of the first region A1 and the slow axis of the fourth region A4. And the angle formed between the slow axis of the third region A3 or the axis perpendicular thereto and the second straight line L2 are equal to each other.

  Here, “equal” for two angles includes not only the case where they are exactly equal, but also the case where both have a relationship that brings about an optical effect that can be identified with human vision. And For example, the two angles need only coincide within an error range of about -5 ° to about 5 °.

  The retardation of the retardation layer 200 is about one-half wavelength with respect to a predetermined design wavelength when the substrate 100 having no retardation is used and the display body 10 is used for transmissive display. It is preferable that The design wavelength is, for example, a wavelength that can be recognized or detected with the highest sensitivity by an observer or a reader. For example, when the display 10 is observed with the naked eye, a wavelength corresponding to green light having the highest visibility among visible light may be set as the design wavelength. Alternatively, in order to make it difficult to recognize the existence of the latent image, a wavelength with lower visibility may be set as the design wavelength.

  When the retardation of the retardation layer 200 is about one-half wavelength, when linearly polarized light is incident on the retardation layer 200, the polarization axis of the linearly polarized light is inverted with respect to the slow axis of the retardation layer 200. . That is, if the angle between the polarization axis of the incident light and the slow axis of the retardation layer 200 is θ, the angle between the polarization axis of the incident light and the polarization axis of the transmitted light is 2θ.

At this time, considering the case where the display body 10 is observed under parallel Nicols, the transmittance T is given by the following equation.

  As described above, in this embodiment, the regions A1 to A4 included in the retardation layer 200 are different from each other in the direction of the slow axis in the in-plane direction. Therefore, when linearly polarized light is incident on the retardation layer 200 and observed through the polarization filter, the transmittances of the regions A1 to A4 can be different from each other according to the above formula. That is, a visible image can be displayed on the display body 10 based on the difference in transmittance between the regions A1 to A4. In addition, when the display body 10 is observed without using a polarizing filter, a visible image is not displayed on the display body 10.

  The image displayed on the display body 10 changes as described below, for example, by rotating the direction of the polarization axis of the polarizing filter in the in-plane direction.

The angle that the slow axis of the first region D1 makes with the X axis is the first angle θ _1, and the angle that the slow axis of the second region D2 makes with the X axis is the second angle θ _2, and the slow angle of the third region D3 The angle that the phase axis makes with the X axis is the third angle θ _3, and the angle that the slow axis of the fourth region D4 makes with the X axis is the fourth angle θ ₄ .

Here, as an example, the angles θ _{1 to} θ ₄ are expressed by the relational expression θ ₂ = θ ₁ + 22.5 ° + 90 ° × L,
θ ₃ = θ ₁ + 45 ° + 90 ° × M and θ ₄ = θ ₁ + 67.5 ° + 90 ° × N
Is satisfied. Note that L, M, and N are arbitrary integers. In this case, as will be described later, an image formed by visualizing each of the latent images shown in FIGS. 2 and 3 can be displayed in the maximum density range.

In the following, in the above formula, when θ ₁ = 0 °, L = 0, M = −1 and N = 0, that is, θ ₁ = 0 °, θ ₂ = 22.5 °, θ ₃ = −45. An example will be described in which the angle is θ and θ ₄ = 67.5 °.

  5 to 8 are plan views showing images displayed when the display body 10 is sandwiched between a pair of polarizing filters and observed.

Hereinafter, the angle formed by the polarization axis of the pair of polarizing filters arranged in parallel Nicols and the X axis shown in FIGS. 5 to 8, that is, the angle formed by the polarization axis of the linearly polarized light to be incident and output and the X axis. Is θ _P. The transmittances in the regions A1 to A4 are T _{1 to} T ₄ , respectively.

5 to 8 schematically show changes in the image observed on the display 10 when θ _P is changed from 0 ° to 90 °.

First, consider the case of θ _P = 11.25 °. At this time, the polarization axis of the polarization filter is bisected by the angle between the slow axis of the first region A1 (θ ₁ = 0 °) and the slow axis of the second region A2 (θ ₂ = 22.5 °). Parallel to the line. The angle formed between the polarization axis of the polarization filter and the slow axis (θ ₃ = −45 °) of the third region A3 is equal to the polarization axis of the polarization filter and the slow axis of the fourth region A4 (θ ₄ = 67. Equal to 5 °).

In this case, the angle formed by the polarization axis of the polarizing filter and the slow axis of the first region A1 is | θ _P −θ ₁ | = 11.25 °. The angle formed by the polarization axis of the polarizing filter and the slow axis of the second region A2 is | θ _P −θ ₂ | = 11.25 °. Therefore, the transmittance in the first region A1 and the second region A2 is T ₁ = T ₂ = 100 × cos ² [(π / 180 °) × 2 × 11.25 °] = 85.4%.

On the other hand, the angle formed by the polarization axis of the polarizing filter and the slow axis of the third region A3 is | θ _P −θ ₃ | = 56.25 °. The angle formed by the polarization axis of the polarizing filter and the slow axis of the fourth region A4 is | θ _P −θ ₄ | = 56.25 °. Therefore, the transmittance in the third region A3 and the fourth region A4 is T ₃ = T ₄ = 100 × cos ² [(π / 180 °) × 2 × 56.25 °] = 14.6%.

  Therefore, in the transmissive display, the regions A1 and A2 are observed as negative images, and the regions A3 and A4 are observed as positive images. That is, the display body 10 displays the first image P1 as a positive image.

In this case, a density range of ΔT = T ₁ −T ₃ = 70.8% can be achieved. That is, the first image P1 can be selectively displayed with an excellent contrast ratio.

Next, consider the case of θ _P = 33.75 °. At this time, the polarization axis of the polarizing filter is bisected by the angle between the slow axis of the first region A1 (θ ₁ = 0 °) and the slow axis of the fourth region A4 (θ ₄ = 67.5 °). Parallel to the line. The angle formed between the polarization axis of the polarizing filter and the slow axis (θ ₂ = 22.5 °) of the second region A2 is an axis orthogonal to the polarizing axis of the polarizing filter and the slow axis of the third region A3 ( θ ₃ + 90 ° = 45 °).

In this case, the angle formed by the polarization axis of the polarizing filter and the slow axis of the first region A1 is | θ _P −θ ₁ | = 33.75 °. The angle formed between the polarization axis of the polarizing filter and the slow axis of the fourth region A4 is | θ _P −θ ₄ | = 33.75 °. Therefore, the transmittance in the first region A1 and the fourth region A4 is T ₁ = T ₄ = 100 × cos ² [(π / 180 °) × 2 × 33.75 °] = 14.6%.

On the other hand, the angle formed by the polarization axis of the polarizing filter and the slow axis of the second region A2 is | θ _P −θ ₂ | = 11.25 °. The angle formed by the polarization axis of the polarizing filter and the slow axis of the third region A3 is | θ _P −θ ₃ | = 78.75 °. Accordingly, the transmittance in the second region A2 and the third region A3 is T ₂ = 100 × cos ² [(π / 180 °) × 2 × 11.25 °] = 100 × cos ² [(π / 180 °). × 2 × 78.75 °] = T ₃ = 85.4%.

  Therefore, in the transmissive display, the regions A1 and A4 are observed as positive images, and the regions A2 and A3 are observed as negative images. That is, the display body 10 displays the second image P2 as a positive image.

In this case, a density range of ΔT = T ₂ −T ₁ = 70.8% can be achieved. That is, the second image P2 can be selectively displayed with an excellent contrast ratio.

Next, consider the case of θ _P = 56.25 °.

In this case, the angle formed by the polarization axis of the polarizing filter and the slow axis of the first region A1 is | θ _P −θ ₁ | = 56.25 °. The angle formed by the polarization axis of the polarizing filter and the slow axis of the second region A2 is | θ _P −θ ₂ | = 33.75 °. Therefore, the transmittance in the first region A1 and the second region A2 is T ₁ = 100 × cos ² [(π / 180 °) × 2 × 56.25 °] = 100 × cos ² [(π / 180 °). × 2 × 33.75 °] = T ₂ = 14.6%.

On the other hand, the angle formed by the polarization axis of the polarizing filter and the slow axis of the third region A3 is | θ _P −θ ₃ | = 78.75 °. The angle formed by the polarization axis of the polarizing filter and the slow axis of the fourth region A4 is | θ _P −θ ₄ | = 11.25 °. Therefore, the transmittance in the third region A3 and the fourth region A4 is T ₃ = 100 × cos ² [(π / 180 °) × 2 × 78.75 °] = 100 × cos ² [(π / 180 °). × 2 × 11.25 °] = T ₄ = 85.4%.

  Therefore, in the transmissive display, the regions A1 and A2 are observed as positive images, and the regions A3 and A4 are observed as negative images. That is, the display body 10 displays the first image P1 as a negative image.

In this case, a density range of ΔT = T ₃ −T ₁ = 70.8% can be achieved. That is, the first image P1 can be selectively displayed with an excellent contrast ratio.

Finally, consider the case of θ _P = 78.75 °.

In this case, the angle formed by the polarization axis of the polarizing filter and the slow axis of the first region A1 is | θ _P −θ ₁ | = 78.75 °. The angle formed by the polarization axis of the polarizing filter and the slow axis of the fourth region A4 is | θ _P −θ ₄ | = 11.25 °. Therefore, the transmittance in the first region A1 and the fourth region A4 is T ₁ = 100 × cos ² [(π / 180 °) × 2 × 78.75 °] = 100 × cos ² [(π / 180 °). × 2 × 11.25 °] = T ₄ = 85.4%.

On the other hand, the angle formed by the polarization axis of the polarizing filter and the slow axis of the second region A2 is | θ _P −θ ₂ | = 56.25 °. The angle formed by the polarization axis of the polarizing filter and the slow axis of the third region A3 is | θ _P −θ ₃ | = 56.25 °. Therefore, the transmittance in the second region A2 and the third region A3 is T ₂ = T ₃ = 100 × cos ² [(π / 180 °) × 2 × 56.25 °] = 14.6%.

  Therefore, in the transmissive display, the regions A1 and A4 are observed as positive images, and the regions A2 and A3 are observed as negative images. That is, the display body 10 displays the second image P2 as a negative image.

In this case, a density range of ΔT = T ₁ −T ₂ = 70.8% can be achieved. That is, the second image P2 can be selectively displayed with an excellent contrast ratio.

Thus, the display body 10 changes the angle θ _P of the polarization axis of the polarizing filter used for observation, thereby changing the positive image of the first image P1, the positive image of the second image P2, and the negative image of the first image P1. And the negative image of the 2nd image P2 can be displayed. Further, as described above, the display body 10 can display these images with a high contrast ratio. Therefore, an observer who knows that the above-described anti-counterfeiting technology is used for the display body 10 can easily determine whether the article including the display body 10 is genuine or counterfeit.

  Various modifications can be made to the display body 10.

  FIG. 9 is a cross-sectional view schematically showing a display body according to a modification.

  The display body 10 shown in FIG. 9 is provided with a reflective layer 300 facing the phase difference phase 200, specifically, the reflective layer 300 is provided between the substrate 100 and the phase difference layer 200. Except this, it has the same configuration as the display body 10 shown in FIG. In the display body 10 shown in FIG. 9, the plurality of latent images described above can be visualized by reflection display.

As a material of the reflective layer 300, for example, a metal, an alloy, or a high refractive index ceramic can be used. As the metal, for example, Al, Sn, Ag, Cr, Ni, or Au can be used. As the alloy, for example, Inconel (registered trademark), bronze, or aluminum bronze can be used. As the ceramic, for example, a high refractive index material such as TiO ₂ , ZnS, and Fe ₂ O ₃ can be used.

  The reflective layer 300 can be formed by methods such as vapor deposition, sputtering, and ion plating, for example. The thickness of the reflective layer 300 is, for example, about 10 nm to about 100 nm.

  When the display body 10 is used for reflection display, it is desirable that the retardation be about a quarter wavelength with respect to the design wavelength described above. In this case, since the light incident on the display body 10 passes through the retardation layer 200 twice before and after reflection, a retardation of about a half wavelength can be achieved in total. Further, a colored layer may be further provided on the main surface of the reflective layer 300 opposite to the main surface facing the retardation layer 200. Thereby, the visibility of the latent image displayed on the display body 10 can be improved.

  FIG. 10 is a cross-sectional view schematically showing a display body according to another modification. In the display body shown in FIG. 10, a diffractive structure is formed in the reflective layer 300. As a result, a more complicated optical effect can be obtained and it becomes more difficult to forge the display body 10. As this diffractive structure, for example, a hologram or a diffraction grating can be used. An image may be formed using this diffractive structure.

  As the hologram, for example, a relief hologram can be used.

  In the case of using a diffraction grating, for example, an image called a grating image or a dot matrix (pixelgram, etc.) can be displayed by arranging a plurality of types of simple diffraction gratings in a minute area to form a pixel. it can.

  These can be obtained, for example, by heating and pressing a press plate on which a hologram or diffraction grating pattern is replicated on the substrate 100, and then forming the reflective layer 300 by, for example, a vapor deposition method.

  FIG. 11 is a cross-sectional view schematically showing a display body according to another modification. The display body 10 shown in FIG. 11 has the same configuration as the display body shown in FIG. 7 except that a diffractive structure forming layer 400 is further provided between the base material 100 and the reflective layer 300. . By forming the diffractive structure in the diffractive structure forming layer 400, even if it is difficult to directly form the diffractive structure on the substrate 100, the same effect as described with reference to FIG. 10 is achieved. can do.

  Note that the reflective layer 300 may be provided in a pattern. In this case, a more complicated optical effect can be achieved, and forgery of the display body 10 becomes more difficult. As a method of providing the reflective layer 300 in a pattern, for example, pasta processing, water-washed sealight processing, or laser processing can be used.

  Further, when the display body 10 is used for reflection display, a reflective material may be used for the substrate 100 instead of providing the reflective layer 300. In this case, for example, a metal foil or a ceramic plate can be used as the substrate 100.

  The display body 10 described with reference to FIGS. 1 to 11 may be used as a part of an adhesive label, a transfer foil, or the like.

  FIG. 12 is a cross-sectional view schematically showing an adhesive label according to one embodiment of the present invention.

  The adhesive label 20 includes a display body 10 and an adhesive layer 500 provided on the display body 10. FIG. 12 shows a case where an adhesive layer 500 is provided on the back surface of the base material 100 of the display body 10 shown in FIG. 9 as an example. For example, the adhesive label 20 is attached to an article whose authenticity is to be confirmed, or is attached to another article such as a base material of a tag to be attached to the article. Thereby, the forgery prevention effect can be provided to the said article | item.

  In addition, the sticking prevention function can also be provided to the pressure-sensitive adhesive label 20 by cutting the base material 100 or further providing a brittle layer between the display body 10 and the pressure-sensitive adhesive layer 500. Thereby, the further superior forgery prevention effect can be achieved.

  FIG. 13 is a cross-sectional view schematically illustrating a transfer foil according to an aspect of the present invention.

  The transfer foil 30 includes a display body 10 and a support layer 600 that supports the display body 10 in a peelable manner. In FIG. 13, as an example, a case where the peeling protective layer 700 is provided between the display body 10 made of the retardation layer 200 and the support layer 600 and the adhesive layer 800 is provided on the main surface of the retardation layer 200. Is drawn.

  The peeling protection layer 700 plays a role of facilitating peeling of the support layer 600 when the transfer foil 30 is transferred to the transfer target. As a material of the peeling protection layer 700, for example, acrylic resin, styrene, or nitrified cotton (nitrocellulose) can be used. The peeling protective layer 700 can be formed by a known method such as a gravure coating method and a micro gravure coating method.

  The adhesive layer 800 includes, for example, a heat-sensitive adhesive that develops tackiness when heat is applied. As the heat-sensitive adhesive, for example, thermoplastic resins such as acrylic resin, vinyl chloride-vinyl acetate copolymer, epoxy resin, and ethylene-vinyl alcohol copolymer can be used. The adhesive layer 800 is obtained, for example, by applying the above-described resin onto the display body 10 including the retardation layer 200 using a coater such as a gravure coater, a micro gravure coater, or a roll coater.

  The transfer foil 30 is transferred to a transfer target by, for example, a roll transfer machine or a hot stamp. At this time, peeling occurs in the peeling protection layer 700 and the display body 10 is attached to the transfer target body via the adhesive layer 800.

  An alignment film may be interposed between the peeling protective layer 700 and the retardation layer 200. Alternatively, an alignment film may be used instead of the peeling protective layer 700. In this case, the above transfer can be performed by utilizing peeling at the interface between the support layer 600 and the alignment film or the interface between the alignment film and the retardation layer 200, cohesive failure of the alignment film, and the like.

  The display body 10 may be supported on the article by other methods.

  For example, when the article includes paper, the display body 10 may be embedded in the paper. In this case, for example, the display body 10 is sandwiched between the fiber layers at the time of paper making, and then printing on the paper surface is performed as necessary. In order to facilitate visualization of the latent image, an opening may be provided in a portion of the paper covering the front surface of the display body 10. Moreover, there is no restriction | limiting in particular in the shape of the display body 10 embedded in paper. For example, the thread-like display body 10 may be embedded in paper. In this way, it is possible to obtain interleaving paper in which the display body 10 is embedded.

  The display body 10, the adhesive label 20, the transfer foil 30, and the interleaving paper described above can be used as a part of a security medium or a product package, for example. As a result, it is possible to impart excellent anti-counterfeiting ability to an article whose authenticity is to be confirmed.

  The display body 10 is manufactured as follows, for example.

  First, the base material 100 is prepared. Then, an orientation layer is formed on the substrate 100.

  As a material for the orientation layer, for example, polyimide or PVA can be used. The orientation layer is formed by a known method such as a gravure coating method, a micro gravure coating method, a spin coating method, or a melt extrusion method.

  Next, in this orientation layer, four regions which are adjacent to each other in the in-plane direction and have different orientation directions are formed. This step can be performed, for example, as follows.

<Photo alignment method>
In this method, a photosensitive layer containing a photosensitive substance is used as the orientation layer. That is, by irradiating the photosensitive layer with polarized light, the photosensitive layer or its functional group is rearranged and an anisotropic chemical reaction is induced to impart anisotropy to the photosensitive layer. As the mechanism, for example, photodimerization reaction of azobenzene derivatives, photodimerization reaction or photocrosslinking reaction of cinnamic acid ester, coumarin, chalcone, benzophenone and their derivatives, and photodecomposition reaction of polyimide can be used. .

  FIG. 14 is a schematic view showing an example of a photomask that can be used when light is applied to the photosensitive layer. In the method using these photomasks, polarized light having different polarization directions, typically linearly polarized light or elliptically polarized light are sequentially switched while sequentially switching the four types of photomasks M1 to M4 with respect to the photosensitive layer. Irradiate. As a result, four regions adjacent to each other in the in-plane direction and having different orientation directions can be formed in the photosensitive layer.

  Instead of these photomasks, a phase difference filter can also be used. For example, by irradiating polarized light, typically linearly polarized light or elliptically polarized light, through a phase difference filter having three or four regions adjacent to each other in the in-plane direction and having different slow axis directions, Three or four regions adjacent to each other in the in-plane direction and having different orientation directions can be formed by one exposure.

  Alternatively, as described below, two phase difference filters having a simpler structure may be used in combination. Also by this method, a structure similar to the above can be obtained by one exposure.

  FIG. 15 is a schematic diagram illustrating an example of a phase difference filter that can be used when light is applied to the photosensitive layer.

  The first phase difference filter F1 has a first part B1 having birefringence, and a second part having birefringence that does not have birefringence or is different from the first part B1. Part B2. The first part B1 and the second part B2 are adjacent to each other in the in-plane direction. The first part B1 has, for example, a slow axis in a certain direction. The second part B2 is, for example, optically isotropic, or has a slow axis direction different from that of the first part B1.

  The second phase difference filter F2 has a third part B3 having birefringence, and a fourth part having birefringence that does not have birefringence or is different from the third part B3. Part B4. The third part B3 and the fourth part B4 are adjacent to each other in the in-plane direction. The third portion B3 has, for example, a slow axis in a certain direction. The fourth portion B4 is, for example, optically isotropic, or the direction of the slow axis is different from that of the third portion B3.

  Each of the phase difference filters F1 and F2 includes, for example, a light transmissive substrate and a phase difference layer formed thereon. In this case, the retardation layer may be a continuous film or may be patterned.

  When a retardation layer is formed as a continuous film on a light-transmitting substrate, two types of regions having different birefringence are provided in the retardation layer so that they are adjacent to each other in the in-plane direction. For example, in the retardation layer, a first region having a slow axis oriented in one direction in the plane is provided in a shape corresponding to the first portion B1 or the third portion B3, and the slow axis is 1 in the plane. A second region that is directed in the direction and whose direction is different from the direction of the slow axis of the first region is provided in a shape corresponding to the second portion B2 or the fourth portion B4. Alternatively, in the retardation layer, a first region having a slow axis directed in one direction in the plane is provided in a shape corresponding to the first portion B1 or the third portion B3, and the optically isotropic first layer is provided. Two regions are provided in a shape corresponding to the second part B2 or the fourth part B4.

  The retardation layer as the continuous film is made of, for example, a polymer liquid crystal material. In this case, the retardation layer is obtained, for example, by forming an alignment film including a plurality of regions having different alignment control directions on a substrate, applying a polymerizable liquid crystal material thereon, and curing the coating film. . Alternatively, the retardation layer is formed by forming an alignment film having substantially the same alignment regulating direction on the substrate, applying a photopolymerizable liquid crystal material thereon, and aligning the liquid crystal material. It is obtained by exposing and curing a part, then changing the phase of the liquid crystal material from the liquid crystal phase to the isotropic phase in the remaining part of the coating by heating, and further curing it by light irradiation or heating. It is done.

  When the retardation layer is formed as a patterned layer on the light-transmitting substrate, the retardation layer is provided in a shape corresponding to the first portion B1 or the third portion B3, for example. Then, the birefringence of the retardation layer is made substantially uniform throughout. In this case, in the phase difference filter F1, the portion where the phase difference layer is not provided corresponds to the second portion B2. Similarly, in the phase difference filter F2, the portion where the phase difference layer is not provided corresponds to the fourth portion B4. When an optically isotropic substrate is used, the second portion B2 and the fourth portion B4 are optically isotropic.

  The patterned retardation layer is made of, for example, a polymer liquid crystal material. In this case, the retardation layer can be formed using, for example, a photolithography method. The patterned retardation layer may be formed using other methods such as a printing method.

  The second part B2 and the fourth part B4 may have birefringence, but are typically optically isotropic. In this case, in addition to the easy design and manufacture of the phase difference filters F1 and F2, the electric field vector relating to the polarized light transmitted through both the second part B2 and the fourth part B4 during the exposure described below. There is no need to consider the rotation.

  The phase difference filters F1 and F2 are used by being overlapped so that a part of the first part B1 and a part of the third part B3 face each other. At this time, typically, the direction of the slow axis of the first part B1 and the direction of the slow axis of the third part B3 are made different from each other.

  When polarized light, typically linearly polarized light or elliptically polarized light is irradiated through the phase difference filters F1 and F2, four regions having different slow axis directions are formed at one time by one exposure. Can do. Here, as an example, a case where exposure is performed using linearly polarized light will be described.

  For example, it is assumed that the first part B1 has a slow axis that forms an angle of −22.5 ° with respect to the X axis, and the second part B2 is optically isotropic. The third portion B3 has a slow axis that forms an angle of 11.25 ° with respect to the X axis, and the fourth portion B4 is optically isotropic. The incident polarized light is linearly polarized light, and its polarization axis is parallel to the X axis.

  In this case, the light that has passed through the first part B1 and the third part B3 orients the photosensitive material in a direction corresponding to −11.25 °. The light that has passed through the first part B1 and the fourth part B4 orients the photosensitive material in a direction corresponding to −22.5 °. The light that has passed through the second part B2 and the third part B3 orients the photosensitive material in a direction corresponding to 11.25 °. The light that has passed through the second part B2 and the fourth part B4 orients the photosensitive material in a direction corresponding to 0 °. In this manner, four regions having different orientation directions can be formed in the photosensitive layer.

<Rubbing orientation method>
In this method, a desired anisotropy is imparted to the orientation layer by rubbing the orientation layer with a cloth. Specifically, a mask having a window corresponding to a region to be aligned is placed on the alignment layer, and a rubbing process is performed in a desired direction from above. By performing this process while sequentially switching a plurality of masks, a plurality of regions having different alignment directions can be formed in the alignment layer.

<Embossed alignment method>
In this method, fine grooves are formed in the alignment layer by embossing, and a liquid crystal substance or the like is aligned according to the direction of the grooves. In this method, for example, a striped pattern is drawn on a positive resist by an electron beam of XY scan, and the uneven shape is created by developing the striped pattern. Thereafter, a resin film or the like is embossed using the uneven shape. In this way, a plurality of regions having different orientation directions are formed in the orientation layer.

  Subsequently, a liquid crystal substance is applied on the alignment layer that has been subjected to alignment treatment by the above-described photo-alignment method, rubbing alignment method, emboss alignment method, or the like. Thereafter, the orientation of the liquid crystal substance is improved by subjecting it to a heat treatment as necessary.

  As the liquid crystal substance, for example, a liquid crystal polymer having orientation or a liquid crystal monomer having a reactive functional group such as an acrylic group can be used. This liquid crystal substance can be applied by a known method such as a gravure coating method and a micro gravure coating method. In addition, when a liquid crystal monomer is used as the liquid crystal substance, after applying the liquid crystal substance on the alignment layer, a curing process is performed by electron beam irradiation, ultraviolet irradiation, heating, a combination thereof, and the like to fix the alignment. .

  In the method using the orientation layer, the orientation layer itself may have birefringence. In this case, each film thickness is adjusted so that the sum of the retardation of the alignment layer and the retardation of the liquid crystal substance becomes the design value. In the case where a desired retardation can be obtained with only the alignment layer, the liquid crystal substance need not be applied.

  In this manner, the retardation layer 200 including the regions A1 to A4 that are adjacent to each other in the in-plane direction and have different slow axis directions is formed on the substrate 100.

  The retardation layer 200 can also be obtained by cutting out a birefringent film and bonding it in a desired shape. Specifically, films having different slow axis directions are attached so as to correspond to each of the regions A1 to A4. Thereby, the phase difference layer 200 including the regions A1 to A4 adjacent to each other in the in-plane direction and having different slow axis directions can be obtained.

  The display body 10 is obtained as described above.

  FIG. 16 is a cross-sectional view schematically showing an example of an adhesive label according to the present invention. In this example, this adhesive label 20 was manufactured as follows.

  First, a base material 100 made of a PET film having a thickness of 38 μm was prepared. And on the base material 100, the diffraction structure formation layer 400 which consists of urethane resin was coated by the thickness of 1 micrometer. This coating was performed by a gravure coating method.

  Next, the diffraction structure image was embossed on the upper surface of the diffraction structure forming layer 400. Thereafter, a reflective layer 300 made of aluminum was formed on the diffractive structure forming layer 400. The reflective layer 300 was formed using a vacuum deposition method so that the thickness was 500 mm.

Thereafter, on the reflective layer 300, a photo-alignment agent IA-01 (manufactured by Dainippon Ink & Chemicals, Inc.) was coated with a thickness of 0.1 μm to form a photosensitive layer. In addition, this coating was performed by the micro gravure coating method. Thereafter, exposure was performed at a dose of 1 J / cm ² using linearly polarized light having a wavelength of 365 nm by the method described above with reference to FIG.

  Next, UV curable liquid crystal UCL-008 (manufactured by Dainippon Ink & Chemicals, Inc.) was applied to the film thus obtained in a thickness of 0.8 μm. In addition, this application | coating was performed using the micro gravure coating method. Thereafter, this was exposed to hot air for 1 minute to align the liquid crystal. Subsequently, curing treatment was performed at an illuminance of 0.5 mJ in a nitrogen gas atmosphere, and the retardation layer 200 was obtained. Finally, after the adhesive layer 500 was applied to the back surface of the substrate 100, the separator 900 was laminated to obtain the adhesive label 20 shown in FIG.

When the adhesive label 20 was attached to an article and observed, no image was observed under natural light. However, when observed through a polarizing filter, a visualized latent image could be observed. Furthermore, two different images could be observed with a high contrast ratio by rotating the polarizing filter in the in-plane direction.
Hereinafter, the invention described in the claims at the beginning of the application will be added.
[1]
A retardation layer including first to fourth regions adjacent to each other in the in-plane direction and having different slow axis directions in the in-plane direction,
The angle formed by the slow axis of the third region and the first straight line with respect to the first straight line that bisects the angle formed by the slow axis of the first region and the slow axis of the second region. And an angle formed between the slow axis of the fourth region or an axis perpendicular thereto and the first straight line is equal to each other,
An angle formed by the slow axis of the second region and the second straight line with respect to a second straight line that bisects the angle formed by the slow axis of the first region and the slow axis of the fourth region. And the angle formed between the slow axis of the third region or an axis perpendicular thereto and the second straight line is the same.
[2]
In the in-plane direction of the retardation layer, an angle formed by the first slow axis with respect to a third straight line parallel to the main surface of the retardation layer is a first angle θ _1, and the second slow axis The second angle θ ₂ is the angle formed by the third slow axis, the third angle θ ₃ is the angle formed by the third slow axis , and the fourth angle θ ₄ is the angle formed by the fourth slow axis. The first angle θ ₁ , the second angle θ ₂ , the third angle θ ₃ , the fourth angle θ _4, and the integers L, M, and N are relational expressions.
θ ₂ = θ ₁ + 22.5 ° + 90 ° × L,
θ ₃ = θ ₁ + 45 ° + 90 ° × M, and
θ ₄ = θ ₁ + 67.5 ° + 90 ° × N
The display body according to [1], wherein:
[3]
The display body according to [1] or [2], further comprising a reflective layer facing the phase difference phase.
[4]
[1] A pressure-sensitive adhesive label comprising the display body according to any one of [3] and an adhesive layer provided on the display body.
[5]
[1] A transfer foil comprising the display according to any one of [3] and a support layer that releasably supports the display.
[6]
The first portion having birefringence and the birefringence which is different from the first portion or does not have birefringence and is adjacent to the first portion in the in-plane direction A first phase difference filter including a second portion, a third portion having birefringence, and a birefringence different from that of the third portion, or not having the birefringence. , Including a fourth part adjacent to the third part in the in-plane direction, and the first part is overlapped with the first phase difference filter so that a part of the first part faces a part of the third part. By irradiating the photosensitive layer with polarized light through the second retardation filter, a plurality of regions adjacent to each other in the in-plane direction and having different molecular or functional group orientations are formed in the photosensitive layer. A method for producing a display body, comprising:

The top view which shows schematically the display body which concerns on 1 aspect of this invention. The top view which shows roughly the latent image currently recorded on the display body shown in FIG. The top view which shows roughly the latent image currently recorded on the display body shown in FIG. Sectional drawing along the IV-IV line of the display body shown in FIG. The top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. The top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. The top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. The top view which shows the image displayed when a display body is pinched | interposed between a pair of polarizing filters and this is observed. Sectional drawing which shows schematically the display body which concerns on one modification. Sectional drawing which shows schematically the display body which concerns on another modification. Sectional drawing which shows schematically the display body which concerns on another modification. Sectional drawing which shows schematically the adhesive label which concerns on 1 aspect of this invention. Sectional drawing which shows schematically the transfer foil which concerns on 1 aspect of this invention Schematic which shows an example of the photomask which can be used in the case of light irradiation to the photosensitive layer. Schematic which shows an example of the phase difference filter which can be used in the case of light irradiation to the photosensitive layer. Sectional drawing which shows schematically an example of the adhesive label which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Display body, 20 ... Adhesive label, 30 ... Transfer foil, 100 ... Base material, 200 ... Retardation layer, 300 ... Reflection layer, 400 ... Diffraction structure formation layer, 500 ... Adhesion layer, 600 ... Support body layer, 700 ... peel protective layer, 800 ... adhesive layer, 900 ... separator, A1 ... first area, A2 ... second area, A3 ... third area, A4 ... fourth area, P1 ... first image, P2 ... second image, B1 ... 1st part, B2 ... 2nd part, B3 ... 3rd part, B4 ... 4th part, F1, F2 ... Phase difference filter, M1, M2, M3, M4 ... Photomask.

Claims (4)

A retardation layer including first to fourth regions adjacent to each other in the in-plane direction and having different slow axis directions in the in-plane direction,
In the in-plane direction of the retardation layer, an angle formed by the first slow axis with respect to a third straight line parallel to the main surface of the retardation layer is a first angle θ _1, and the second slow axis The second angle θ ₂ is the angle formed by the third slow axis, the third angle θ ₃ is the angle formed by the third slow axis, and the fourth angle θ ₄ is the angle formed by the fourth slow axis. The first angle θ ₁ , the second angle θ ₂ , the third angle θ _3, and the fourth angle θ ₄ are expressed by a relational expression θ ₂ = θ ₁ + 22.5 °,
θ ₃ = θ ₁ - 4 5 °, and θ ₄ = θ ₁ +67.5 °
It meets the,
In the retardation layer, a first image corresponding to the first area and the fourth area, and a second image corresponding to the third area and the fourth area are recorded as latent images,
The first image is a case where the retardation layer is observed through a polarizer, and an angle θ _p formed by a polarization axis of the polarizer with respect to the third line is
θ _p = 11.25 ° or θ _p = 56.25 °
Visualize when meeting,
The second image is a case where the retardation layer is observed through a polarizer, and an angle θ _p formed by a polarization axis of the polarizer with respect to the third line is
θ _p = 33.75 ° or θ _p = 78.75 °
Visualize when meeting ,
The display body, wherein the visualized first and second images are used for discrimination between genuine products and counterfeit products.   The display body according to claim 1, further comprising a reflective layer facing the phase difference phase.   An adhesive label comprising the display body according to claim 1 and an adhesive layer provided on the display body.   A transfer foil comprising the display body according to claim 1 and a support layer that releasably supports the display body.

Images