Identification medium, article, and method of using identification medium

Abstract

The present invention provides an identification medium, which has a light reflection layer and a patterned phase difference layer, wherein the light reflection layer is a layer that reflects incident light into circularly polarized light or linearly polarized light, and the patterned phase difference layer is a layer that includes a region with a phase difference, and the region with a phase difference is provided on the identification medium in a manner that occupies a portion of the display surface of the identification medium. The present invention also provides an article having the identification medium and a method for using the identification medium, in which, when observing the reflected light, the linear polarization component of the reflected light is selectively observed, or the linear polarization light is made incident as the incident light.

Description

Technical Field

[0001] The present invention relates to an identification medium, an article and a method for using the identification medium. Background Art

[0002] In order to easily determine whether an item is genuine, an identification medium is usually set on the item. The identification medium is required to have anti-counterfeiting performance and identification function. The anti-counterfeiting performance of the identification medium referred to here means that the identification medium cannot be easily copied by conventional printing and other technologies. The identification function of the identification medium means that it can distinguish the genuine identification medium from the counterfeit identification medium forged by conventional technology with high reliability in some way.

[0003] In the case of most identification media, the authenticity of the identification medium is determined by observing through a special determination tool including an optical member such as a circular polarizer or a linear polarizer (for example, Patent Documents 1 to 3). On the other hand, there are also identification media that do not require a special determination tool and can be determined by observation with the naked eye, such as so-called holograms, which are determined based on whether a pattern on the identification medium can be observed in three dimensions (for example, Patent Document 4).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-221650;

[0007] Patent Document 2: Japanese Patent Application Publication No. 2010-113249 (corresponding publication: U.S. Patent Application Publication No. 2010 / 119738);

[0008] Patent document 3: International Publication No. 2005 / 059597;

[0009] Patent document 4: Japanese Patent No. 5915838. Summary of the invention

[0010] Problem that the invention aims to solve

[0011] For identification media that require special judgment tools to judge authenticity, the personnel who can make judgments are limited. That is, only special identifiers such as tax officials who have special judgment tools can make judgments. On the other hand, ordinary object users who buy, sell, hold, and use objects cannot make judgments because they do not have the special judgment tools. In addition, when judging the authenticity of the identification media of Patent Documents 1 and 2, a special operation such as bringing the judgment tool close to the identification medium is required.

[0012] In the case of an identification medium that makes judgment based on a so-called hologram without requiring a special judgment tool, there are fewer restrictions on the personnel who make judgments, but on the other hand, since it is already possible to produce counterfeit products that can achieve a relatively similar effect through conventional hologram technology, the anti-counterfeiting performance is sometimes insufficient. In the case of observing the hologram through a special judgment tool, a structure with higher anti-counterfeiting performance can be obtained, but the situation is the same as above, and the personnel who make judgments are limited.

[0013] Therefore, an object of the present invention is to provide an identification medium having high anti-counterfeiting performance and capable of utilizing an identification function without using a special determination tool, an article having the identification medium, and an authenticity determination method.

[0014] Solutions for solving problems

[0015] The inventors conducted research to solve the above problems and envisioned that a recognition medium whose recognition function can be utilized by using a common device in a common manner of use, such as polarized sunglasses and devices that emit polarized light such as liquid crystal display devices, etc. The inventors conducted further research based on this concept and found that when a specific recognition medium is constructed, the recognition function can be utilized and good anti-counterfeiting performance can be obtained by using the above-mentioned common devices, thereby completing the present invention.

[0016] That is, the present invention includes the following aspects.

[0017] [1] An identification medium comprising a light reflecting layer and a patterned phase difference layer,

[0018] The light reflecting layer is a layer that reflects incident light into circularly polarized light or linearly polarized light.

[0019] The patterned phase difference layer is a layer including a region having a phase difference, and the region having a phase difference is provided on the identification medium so as to occupy a part of the display surface of the identification medium.

[0020] [2] The identification medium according to [1], wherein the patterned phase difference layer is provided at a position closer to the viewing side than the light reflecting layer.

[0021] [3] The identification medium according to [1] or [2], wherein the light reflecting layer is a reflective circular polarizer or a reflective linear polarizer.

[0022] [4] The identification medium according to [3], wherein the light reflecting layer is the reflective circular polarizer.

[0023] [5] The identification medium according to any one of [1] to [4], wherein the patterned phase difference layer includes a region that functions as a λ / 4 wave plate or a λ / 2 wave plate as the region having a phase difference.

[0024] [6] The identification medium according to any one of [1] to [5], wherein the identification medium has one or more independent patterned phase difference layers as the patterned phase difference layer,

[0025] The independent patterned phase difference layer is composed of a region having a size smaller than the display surface of the identification medium and having a certain phase difference.

[0026] [7] The identification medium according to any one of [1] to [6], wherein the identification medium has a plurality of regions whose slow axis directions are irregularly different as the regions having phase differences.

[0027] [8] The identification medium according to any one of [1] to [7], wherein the light reflecting layer is a slice of a material having cholesteric regularity.

[0028] [9] The identification medium according to any one of [1] to [8], wherein the light reflecting layer includes two or more regions where the polarization states of the reflected light are different.

[0029]

[10] An identification medium according to any one of [1] to [9], wherein, in one or more regions of the light reflecting layer, the reflectivity of the non-polarized light incident on the region in the light reflecting layer is 35% to 50% at all wavelengths in the wavelength range of 420 nm to 650 nm.

[0030]

[11] The identification medium according to any one of [1] to

[10] , further comprising a light absorbing layer at a position on the opposite side of the light reflecting layer to the viewing side.

[0031]

[12] The identification medium according to any one of [1] to

[11] , further comprising a diffusion layer at a position closer to the viewing side than the patterned phase difference layer.

[0032]

[13] The identification medium according to any one of [1] to

[12] , further comprising a transparent resin portion, wherein all or part of the components other than the transparent resin portion are embedded in the transparent resin portion.

[0033]

[14] The identification medium according to any one of [1] to

[13] , further comprising a mounting member for mounting on an article.

[0034]

[15] An article having the identification medium according to any one of [1] to

[14] .

[0035]

[16] The article according to

[15] , wherein the article further comprises a polarizer observation device.

[0036]

[17] A method of use, which is the method of use of the identification medium described in any one of [1] to

[14] ,

[0037] The method of use comprises: allowing incident light to be incident on the display surface of the identification medium, being reflected in the light reflection layer to form reflected light, observing the reflected light,

[0038] When non-polarized light is incident as the incident light and the reflected light is observed, a linear polarization component or a circular polarization component of the reflected light is selectively observed.

[0039]

[18] The method of use according to

[17] , wherein the selective observation is performed by visually observing the reflected light through a linear polarizer separated from the identification medium.

[0040]

[19] The method of use according to

[18] , wherein the linear polarizer is polarized sunglasses.

[0041]

[20] A method of use, which is the method of use of the identification medium described in any one of [1] to

[14] ,

[0042] The method of use comprises: allowing incident light to be incident on the display surface of the identification medium, being reflected in the light reflection layer to form reflected light, observing the reflected light,

[0043] Linearly polarized light, circularly polarized light, or elliptically polarized light is made incident as the incident light.

[0044] Effects of the Invention

[0045] According to the present invention, it is possible to provide an identification medium having high anti-counterfeiting performance and capable of utilizing an identification function without using a special determination tool, an article having the identification medium, and an authenticity determination method. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a perspective exploded view schematically showing an example of the identification medium of the present invention and a method of using the same.

[0047] Figure 2 The figure is an exploded side view schematically showing an example of the identification medium of the present invention and a method of using the same.

[0048] Figure 3 To show the observed value from the Z-axis direction Figure 1A top view of the state of the coordinate axis is shown.

[0049] Figure 4 To schematically illustrate the changes Figure 1 and Figure 2 An exploded side view of an example of a method of using the identification medium of the present invention in the case of a relative angle relationship between the identification medium and the observation linear polarizer in the example.

[0050] Figure 5 To schematically illustrate Figure 1 , Figure 2 and Figure 4 A side exploded view of another example of a method of using the identification medium 100 is shown.

[0051] Figure 6 To schematically illustrate the changes Figure 5 A side exploded view of an example of a method of using the identification medium of the present invention in the case of a relative angular relationship between the vibration direction of the identification medium and the incident linear polarized light in an example.

[0052] Figure 7 The figure is a side exploded view schematically showing another example of the identification medium and the method for using the same according to the present invention.

[0053] Figure 8 To schematically illustrate the changes Figure 7 An exploded side view of an example of a method of using the identification medium of the present invention in the case of a relative angle relationship between the identification medium and the observation linear polarizer in the example.

[0054] Fig. 9 To schematically illustrate Figure 7 and Figure 8 A side exploded view of another example of a method of using the identification medium 200 is shown.

[0055] Fig.10 To schematically illustrate the changes Fig. 9 A side exploded view of an example of a method of using the identification medium of the present invention in the case of a relative angular relationship between the vibration direction of the identification medium and the incident linear polarized light in an example.

[0056] Fig.11 It is a top view schematically showing a specific example of the identification medium of the present invention.

[0057] Fig.12 for Fig.11 A longitudinal cross-sectional view of the identification medium shown. DETAILED DESCRIPTION

[0058] Hereinafter, the present invention will be described in detail by showing examples and embodiments. However, the present invention is not limited to the examples and embodiments shown below, and can be implemented with arbitrary changes without departing from the scope of the claims of the present invention and the scope of their equivalents.

[0059] In the following description, unless otherwise specified, "(meth)acryloyl" is a term including "acryloyl", "methacryloyl" and a combination thereof.

[0060] In the following description, unless otherwise specified, the in-plane retardation Re of a certain layer is a value represented by Re=(nx-ny)×d. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) giving the maximum refractive index. Ny represents the refractive index in the direction perpendicular to the direction of nx in the above-mentioned in-plane direction of the layer. d represents the thickness of the layer. Unless otherwise specified, the measurement wavelength of the delay is 590nm. In addition, the Re measured at a certain wavelength (unit nm) is represented by a symbol with a number such as Re(450). For example, Re(450) represents the Re for light with a wavelength of 450nm. The in-plane retardation Re can be measured using a phase difference meter ("AxoScan" manufactured by AxoMetrix).

[0061] In the following description, unless otherwise specified, the direction of the slow axis of a certain layer means the direction of the slow axis in the in-plane direction.

[0062] In the following description, unless otherwise specified, the directions of the components "parallel" and "perpendicular" may include errors within the range of, for example, ±4°, preferably ±3°, and more preferably ±1°, within the range not impairing the effects of the present invention.

[0063] In the following description, for the sake of convenience, "right-handed circularly polarized light" and "left-handed circularly polarized light" are defined based on the following rotation direction: the rotation direction of circularly polarized light when the light emission target is observed from the light emission source. That is, when the light emission target is observed from the light emission source, along the traveling direction of the light, polarized light whose polarization direction rotates clockwise is defined as right-handed circularly polarized light, and polarized light whose polarization direction rotates counterclockwise is defined as left-handed circularly polarized light.

[0064] In the following drawings and the related descriptions, the following symbols are used to facilitate easy understanding. Figures 1 to 10 The directions shown and the directions described in the description are used as a reference. In addition, the vibration direction of polarized light refers to the vibration direction of the electric field.

[0065] (N): non-polarized light, or isotropic layer for light transmission

[0066] (X): Linearly polarized light with a vibration direction in the X-axis direction, or a polarizer with a transmission axis in the X-axis direction

[0067] (Y): Linearly polarized light with a vibration direction in the Y-axis direction, or a polarizer with a transmission axis in the Y-axis direction

[0068] (L): left-handed circularly polarized light, or a left-handed reflective circular polarizer (i.e., a reflective circular polarizer that selectively reflects the left-handed circularly polarized component of incident light)

[0069] (R): right-handed circularly polarized light, or a right-handed reflective circular polarizer (i.e., a reflective circular polarizer that selectively reflects the right-handed circularly polarized component of incident light)

[0070] (n): No light exists

[0071] (XY): XY direction, or a phase difference layer with a slow axis in the XY direction

[0072] (Xy): Xy direction, or a phase difference layer having a slow axis in the Xy direction

[0073] In the following description, unless otherwise specified, the identification medium is described in a state where the display surface faces upward and is placed horizontally. Therefore, the side from which the identification medium is viewed is sometimes referred to as the "upper" side, and the opposite side is sometimes referred to as the "lower" side. For example, the surface on one side and the surface on the other side of a layer that is closer to the display surface of the identification medium is sometimes referred to as the "upper" surface. In addition, the direction perpendicular to the "upper" and "lower" directions is sometimes referred to as the "horizontal" direction.

[0074] [Identification medium: Embodiment 1]

[0075] The identification medium of the present invention comprises a light reflecting layer and a patterned phase difference layer.

[0076] Figure 1 and Figure 2 The following is a perspective exploded view and a side exploded view schematically showing an example of the identification medium of the present invention and its use method. Figure 1-2 and Figures 4 to 10 In the figure, the structural elements of the identification medium are shown in a separated state, but in the actual identification medium, they can be in direct contact or in contact with each other through other layers. Figure 1 and Figure 2In the example, the identification medium 100 has a light reflection layer 101 (R) and a patterned phase difference layer 102. In this example, the entire area of ​​the upper surface 101 (R)U of the light reflection layer 101 (R) is an area corresponding to the display surface, and the patterned phase difference layer 102 occupying the entire area is provided. Only a part of the patterned phase difference layer 102 is a layer 102 (Xy) that functions as a λ / 4 wave plate, and the other part is an isotropic layer 102 (N).

[0077] The patterned phase difference layer is usually arranged at a position closer to the viewing side than the light reflecting layer. Therefore, the display surface of the identification medium is usually the surface on the patterned phase difference layer side of the identification medium. Figure 1 and Figure 2 In the example of the identification medium 100, the upper surface 102U of the patterned phase difference layer 102 of the identification medium 100 functions as a display surface. That is, part of the light incident on the surface 102U of the identification medium 100 is reflected inside the identification medium 100 and emitted from the surface 102U, and the observer observes the emitted light, thereby demonstrating the function as the identification medium.

[0078] For ease of explanation, Figures 1 to 10 In , directions in space are represented by common three-dimensional coordinate axes. In the coordinate axes represented by arrows X, Y, and Z, the direction parallel to arrow X, the direction parallel to arrow Y, and the direction parallel to arrow Z are referred to as the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. Figure 1-2 and Figures 4 to 10 In the embodiment, the identification medium 100 or 200 is positioned so that its display surface is in a direction parallel to the XY plane.

[0079] Figure 3 To show the observed value from the Z-axis direction Figure 1 The direction in the XY plane that forms an angle of 45° with the arrows X and Y (i.e., Figure 3 The direction parallel to the arrow XY in the figure is referred to as the XY direction. In addition, the direction at an angle of 45° to the arrow X and 135° to the arrow Y (i.e., Figure 3 The direction parallel to the arrow Xy in the figure is called the Xy direction.

[0080] [Overview of Optical Properties of Light Reflecting Layer]

[0081] The light reflecting layer is a layer that reflects incident light into circularly polarized light or linearly polarized light. Specifically, the light reflecting layer is a layer that reflects a certain polarization component of non-polarized light containing various polarization components into circularly polarized light or linearly polarized light when non-polarized light containing various polarization components is incident. The light reflecting layer is usually a reflective polarizer. That is, the light reflecting layer transmits a part or all of the polarization components of a certain wavelength in the incident light, and reflects a part or all of the other polarization components. As the light reflecting layer, a reflective circular polarizer or a reflective linear polarizer can be used.

[0082] A reflective circular polarizer is an optical element that transmits one of the right-handed circular polarization component and the left-handed circular polarization component of incident light of a certain wavelength and reflects the other. A reflective linear polarizer is an optical element that transmits one of the linear polarization component and the linear polarization component perpendicular to the component of incident light of a certain wavelength and reflects the other.

[0083] exist Figure 1 and Figure 2 In the example, a right-handed reflective circular polarizer (i.e., a reflective circular polarizer that selectively reflects the right-handed circular polarization component in the incident light) is used as the light reflecting layer 101 (R). A more specific description of the example of the light reflecting layer and its constituent materials will be described later.

[0084] [Overview of Optical Properties of Patterned Phase Difference Layer]

[0085] The patterned phase difference layer refers to a layer including a region with a phase difference, which is provided on the identification medium in a manner that occupies a portion of the display surface of the identification medium. In the following description, the portion of the region with a phase difference in the patterned phase difference layer is sometimes referred to as simply a "phase difference layer".

[0086] The area other than the area occupied by a certain phase difference layer in the display surface may be an area occupied by other phase difference layers having different phase differences, an area occupied by an isotropic layer having no phase difference, or an area where none of these exist.

[0087] As an example of a region with a phase difference, a region that functions as a λ / 4 wave plate and a region that functions as a λ / 2 wave plate can be cited. The region that functions as a λ / 4 wave plate refers to a region in which the in-plane delay Re is λ / 4 or a value close thereto in at least one wavelength λ within the wavelength band in which the light reflecting layer functions. For example, a region in which Re is ((λ / 4)×0.6)nm to ((λ / 4)×1.4)nm, and preferably a region in which Re is ((λ / 4)×0.8)nm to ((λ / 4)×1.2)nm can be used as a region with a phase difference. Similarly, a region that functions as a λ / 2 wave plate refers to a region in which the in-plane delay Re is λ / 2 or a value close thereto, for example, a region in which Re is ((λ / 2)×0.6)nm to ((λ / 2)×1.4)nm, and preferably a region in which Re is ((λ / 2)×0.8)nm to ((λ / 2)×1.2)nm.

[0088] exist Figure 1 and Figure 2 In the example of , the patterned phase difference layer 102 is a combination of a layer 102 (Xy) functioning as a λ / 4 wave plate and an isotropic layer 102 (N) arranged side by side in the horizontal direction. Therefore, the area occupied by the layer 102 (Xy) occupies a part of the display surface of the identification medium 100. The layer 102 (Xy) has a slow axis in the Xy direction, that is, in the direction indicated by the arrow A102 (Xy). A more specific description of the example of the patterned phase difference layer and its constituent materials will be described later.

[0089] [Method of using the identification medium according to Embodiment 1: Part 1]

[0090] In the method of using the identification medium of the present invention, incident light is made incident on the display surface of the identification medium, reflected by the light reflecting layer to become reflected light, and the reflected light is observed.

[0091] Examples of light incident on the identification medium include non-polarized light, linearly polarized light, circularly polarized light, and elliptically polarized light. When the incident light is non-polarized light, the identification medium can be used by selectively observing the linear polarization component or circular polarization component of the reflected light when observing the reflected light.

[0092] As the incident non-polarized light, normal ambient light such as sunlight and indoor lighting light can be used.

[0093] Selectively observing the linear polarization component of the reflected light can be performed by visually observing the reflected light across the observation linear polarizer. Selectively observing the circular polarization component of the reflected light can be performed by visually observing the reflected light across the observation circular polarizer. In order to avoid obstruction of the incidence of ambient light, the observation linear polarizer and the observation circular polarizer can usually be used in a state separated from the identification medium. The lower limit of the separation distance can be appropriately adjusted according to the size of the identification medium and the observation linear polarizer, and can usually be more than 100mm. On the other hand, the upper limit of the separation distance can be appropriately adjusted within the range where the reflected light of the identification medium can be observed, and can usually be less than 30m.

[0094] As such, the linear polarizer for observation used at a position separated from the identification medium may be a special product for the method of use of the present invention, or may be a conventional linear polarizer for other purposes. For example, since most commercially available polarized sunglasses can function as linear polarizers, such commercially available polarized sunglasses may also be used as linear polarizers for observation. As examples of circular polarizers for observation, there may be cited a circular polarizer consisting of a combination of a linear polarizer and a phase difference film, and a circular polarizer comprising a layer of a cholesteric material (e.g., those described in International Publication No. 2020 / 121791).

[0095] exist Figure 1 and Figure 2 In the example, the following is shown: the light incident on the identification medium 100 is non-polarized light, and the reflected light from the identification medium 100 is observed through the observation linear polarizer 191 (X). In this example, the observation linear polarizer 191 (X) is a polarizer that is positioned at a relative angle with the identification medium 100 so that the observation linear polarizer 191 (X) has a transmission axis in the X-axis direction, that is, in the direction indicated by the arrow A191 (X). Therefore, in this example, the slow axis of the layer 102 (Xy) is deflected 45° counterclockwise relative to the transmission axis of the observation linear polarizer 191 (X). That is, when the observation linear polarizer 191 (X) and the identification medium 100 are observed from the viewing side, when the transmission axis direction of the observation linear polarizer 191 (X) is used as a reference, the slow axis of the layer 102 (Xy) is deflected 45° counterclockwise relative to the reference. In the following description of Figures 1 to 10 In the description of , "clockwise" and "counterclockwise" have the same meaning.

[0096] Figure 2 and Figures 4 to 10 The values ​​in brackets in are the theoretical values ​​of the brightness of each layer of light when the brightness of the incident light is 100. Here, the theoretical value refers to the value obtained when the polarized light separation by the polarizer is completely performed (in Figure 2In the example, the right-handed circularly polarized component of the light incident on the light reflecting layer 101 (R) is completely reflected, the left-handed circularly polarized component is completely transmitted, and the linear polarization component in the X-axis direction of the light incident on the observation linear polarizer 191 (X) is completely transmitted, and all other linear polarization components are absorbed or reflected and blocked), and the patterned phase difference layer does not absorb any light.

[0097] exist Figure 1 and Figure 2 In the illustrated example of use of the identification medium 100 , incident light A111 (N) and A121 (N) as non-polarized light are incident on the layer 102 (Xy) functioning as a λ / 4 wave plate and the isotropic layer 102 (N) in the patterned phase difference layer 102 , respectively.

[0098] The incident light A111(N) passes through the layer 102(Xy) and is emitted downward as non-polarized light A112(N), reaching the upper surface 101(R)U of the light reflecting layer 101(R). Since the light reflecting layer 101(R) is a right-handed reflective circular polarizer, the right-handed circular polarization component in the light A112(N) is reflected on the surface or inside of the light reflecting layer 101(R) to form reflected light A113(R), whose theoretical brightness is half of that of the incident light. On the other hand, the left-handed circular polarization component in the light A112(N) passes through the light reflecting layer 101(R) to form transmitted light A119(L).

[0099] Light A113 (R) transmits layer 102 (Xy) again to form light A114 (Y), which is emitted from the display surface of the identification medium 100. Since light A113 (R) is right-handed circularly polarized light and layer 102 (Xy) is a λ / 4 wave plate having a slow axis in the XY direction, light A114 (Y) becomes linearly polarized light having a polarization direction in the Y-axis direction, and its theoretical brightness is the same as that of light A113 (R).

[0100] When the emitted light A114 (Y) is incident on the observation linear polarizer 191 (X), the vibration direction of the polarized light of the light A114 (Y) is perpendicular to the transmission axis of the observation linear polarizer 191 (X), so the light A114 (Y) is completely blocked, and the theoretical value of the brightness of the emitted light A115 (n) from the observation linear polarizer 191 (X) is 0.

[0101] On the other hand, the incident light A121(N) passes through the layer 102(N) and is emitted downward as non-polarized light A122(N) to reach the upper surface 101(R)U of the light reflecting layer 101(R). The right-handed circularly polarized component in the light A122(N) is reflected to form reflected light A123(R), whose theoretical brightness is half that of the incident light. On the other hand, the left-handed circularly polarized component in the light A122(N) passes through the light reflecting layer 101(R) to form transmitted light A129(L).

[0102] The light A123(R) transmits through the layer 102(N) again to form the light A124(R), which is emitted from the display surface of the identification medium 100. The theoretical value of the brightness of the light A124(R) is the same as that of the light A123(R).

[0103] When the emitted light A124(R) enters the observation linear polarizer 191(X), only the linear polarization component having the vibration direction in the X-axis direction in the light A124(R) is emitted from the observation linear polarizer 191(X) as the emitted light A125(X). The theoretical value of the brightness of the emitted light A125(X) is half of that of the light A124(R).

[0104] As a result, when observing the identification medium 100 in a state where non-polarized light is incident through the linear polarizer 191 (X), the area occupied by the layer 102 (Xy) is observed to be a relatively dark area with no reflected light, and on the other hand, the area occupied by the layer 102 (N) is observed to be a relatively bright area with reflected light having a brightness of 1 / 4 of the incident light.

[0105] Figure 4 To schematically illustrate the changes Figure 1 and Figure 2 An exploded side view of an example of a method of using the identification medium of the present invention in the case of a relative angle relationship between the identification medium and the observation linear polarizer in the example. Figure 4 , the angle of the identification medium 100 relative to the coordinate axis is fixed and the angle of the observation linear polarizer relative to the X-axis and the Y-axis is changed. However, in actual use, the relative angle relationship between the identification medium and the observation linear polarizer can be changed by moving the identification medium, moving the observation linear polarizer, replacing the observation linear polarizer, or combining two or more of these.

[0106] exist Figure 4In the example of , as a result of changing the angle relationship, the observation linear polarizer 191 (Y) is used as the observation polarizer. The observation linear polarizer 191 (Y) is a polarizer that is positioned at a relative angle with the identification medium 100 so that the observation linear polarizer 191 (Y) has a transmission axis in the Y-axis direction. Therefore, in this example, the slow axis of the layer 102 (Xy) is deflected 45° clockwise relative to the transmission axis of the observation linear polarizer 191 (Y).

[0107] exist Figure 4 In the example of use of the identification medium 100 shown in FIG. 1 , incident light A111(N) and A121(N) as non-polarized light are incident on the layer 102(Xy) and the isotropic layer 102(N) functioning as a λ / 4 wave plate in the patterned phase difference layer 102, respectively, and a portion of each of them is emitted from the display surface of the identification medium 100 as light A114(Y) and light A124(R), respectively. The path of light so far is similar to that of FIG. Figure 1 and Figure 2 Same as the example.

[0108] When the emitted light A114 (Y) enters the observation linear polarizer 191 (Y), since the polarization vibration direction of the light A114 (Y) is parallel to the transmission axis of the observation linear polarizer 191 (Y), the light A114 (Y) is completely transmitted to form the emitted light A115 (Y), which is emitted from the observation linear polarizer 191 (Y). The theoretical value of the brightness of the emitted light A115 (Y) is the same as that of the light A114 (Y).

[0109] On the other hand, when the emitted light A124(R) enters the observation linear polarizer 191(Y), only the linear polarization component having the vibration direction in the Y-axis direction of the light A124(R) is emitted from the observation linear polarizer 191(Y) as the emitted light A125(Y). The theoretical value of the brightness of the emitted light A125(Y) is half of that of the light A124(R).

[0110] As a result, when observing the identification medium 100 in a state where non-polarized light is incident through the observation linear polarizer 191 (Y), the area occupied by the layer 102 (Xy) is observed to be a relatively bright area of ​​reflected light having a brightness of 1 / 2 of the incident light. On the other hand, the area occupied by the layer 102 (N) is observed to be a relatively bright area of ​​reflected light having a brightness of 1 / 4 of the incident light. The brightness of the layer 102 (N) is relatively bright. Figure 1 and Figure 2 There is no change from what is shown, but in this example, layer 102 (N) is observed as a relatively dark area compared to the area occupied by layer 102 (Xy).

[0111] Therefore, by changing the relative angle between the identification medium and the observation linear polarizer from Figure 1 and Figure 2 In the example, the relationship is changed to Figure 4 In the example of , the relative brightness between the multiple regions when observing through the linear polarizer is changed. More specifically, when Figure 1 and Figure 2 When the orientation of the linear polarizer for observation is changed by rotating the linear polarizer about an axis parallel to the Z-axis direction, the relative brightness of the area occupied by the layer 102 (Xy) becomes brighter as the rotation angle increases. Figure 4 When the linear polarizer 191 (Y) is in the observation state, the relative brightness is maximum.

[0112] When such a brightness change is achieved in the entire visible region or a wide wavelength range close thereto, the brightness change can be observed as a change from black in a dark state to silver in a bright state. When the brightness change is achieved only in a wavelength range of a part of the visible region, the brightness change can be observed as a change in color corresponding to the wavelength range in which the change occurs.

[0113] On the other hand, when observing the identification medium 100 in a state where non-polarized light is incident without using a linear polarizer, the observer observes the outgoing light A114 (Y) and A124 (R). The outgoing light A114 (Y) and A124 (R) have different polarization states but the same brightness. Since human vision cannot recognize the difference in polarization states, the observer cannot recognize the difference between them. In addition, even if the relative angle relationship between the identification medium 100 and the observer changes, the observer cannot recognize the changes caused by the change in polarization state.

[0114] In the method of use of this example, the identification medium of the present invention can bring about a special effect, that is, the change in relative brightness can only be observed when the linear polarizer is separated. Such a special effect cannot be obtained by using a replica that is easily obtained by using conventional printing and other technologies. Therefore, the identification medium of the present invention exerts a high anti-counterfeiting performance in such use.

[0115] By changing the relative brightness, characters, graphics, etc. can be displayed on the display surface. Such an image that cannot be observed by normal observation and can only be observed by specific observation of the identification medium is called a "latent image" of the identification medium.

[0116] In addition, such a special effect can be obtained by using non-polarized light as incident light and selectively observing the linear polarization component of the reflected light. Such observation can be achieved by using ambient light as incident light, visually observing the reflected light through the observation linear polarizer when the identification medium is separated from the observation linear polarizer as a judgment tool. Furthermore, as the observation linear polarizer, a common polarizer such as commercially available polarized sunglasses can be used. Therefore, such observation can be performed without special operations such as bringing the judgment tool close to the identification medium, and relatively easy-to-obtain items can be used as judgment tools. For example, identification can be achieved through such easy actions as visually observing the identification medium placed at a position separated from the observer while wearing polarized sunglasses. Therefore, the identification medium of the present invention exerts a high recognition function in such use.

[0117] exist Figure 1-2 and Figure 4 In the example shown, observation is performed in a state where the identification medium and the observation linear polarizer are separated, but the positional relationship between the identification medium and the observation linear polarizer during observation is not limited to this. For example, even when observation is performed in a state where the observation linear polarizer is placed on the identification medium and the observation linear polarizer is close to each other, such a latent image can be observed.

[0118] In the above example, an example of using linear polarizers (linear polarizer 191 (X) for observation and linear polarizer 191 (Y) for observation) as polarizers for observation is shown, but the present invention is not limited to this, and polarizers other than linear polarizers can also be used as polarizers for observation.

[0119] As an example, a right-handed circular polarizer, a left-handed circular polarizer, or a combination thereof can be used as a polarizer for observation instead of a linear polarizer. When the light A114 (Y) and A124 (R) are observed through a right-handed circular polarizer that selectively transmits right-handed circularly polarized light, their brightness (relative theoretical value when the brightness of the incident light is set to 100) is 25 and 50, respectively, and the isotropic layer 102 (N) is observed to be a relatively bright area.

[0120] On the other hand, when light A114 (Y) and A124 (R) are observed through a left-handed circular polarizer that selectively transmits left-handed circularly polarized light, their brightness is 25 and 0, respectively, and layer 102 (Xy) functioning as a λ / 4 wave plate is observed as a relatively bright area.

[0121] Therefore, by comparing two or more of observation without a circular polarizer, observation via a right-handed circular polarizer, and observation via a left-handed circular polarizer, it is possible to demonstrate the identification function based on the resulting change in relative brightness.

[0122] [Method of using the identification medium of Embodiment 1: Part 2]

[0123] The above example is an example of a method of using non-polarized light as the light incident on the identification medium 100. On the other hand, an example of a method of using linearly polarized light as the light incident on the identification medium 100 will be described below.

[0124] When the incident light is polarized light (linearly polarized light, circularly polarized light, or elliptically polarized light), when observing the reflected light, the reflected light can be directly observed visually without using a linear polarizer for observation.

[0125] When the incident polarized light is linearly polarized light, linearly polarized light obtained by transmitting non-polarized light through a linear polarizer can be used as the linear polarized light. The device for providing linear polarized light can be a special product for the method of use of the present invention, or a combination of a common light source and a common linear polarizer for other purposes can be used. In addition, a device in a state of combining a common light source and a linear polarizer for other purposes can also be used.

[0126] When the incident polarized light is circularly polarized light, the circularly polarized light obtained by transmitting the non-polarized light through the circular polarizer can be used as the circularly polarized light. The device for providing the circularly polarized light can be a special product for the method of use of the present invention, or a common light source and a common circular polarizer for other purposes can be used in combination. In addition, a device in a state of a common light source and a circular polarizer for other purposes can also be used.

[0127] When the incident polarized light is elliptically polarized light, as the elliptically polarized light, elliptically polarized light obtained by transmitting non-polarized light through an appropriate optical element can be used. The device for providing elliptically polarized light can be a special product for the method of use of the present invention, or a common light source for other purposes and a common linear polarizer or circular polarizer can be used in combination. In addition, a device in a state of a combination of a common light source for other purposes and a linear polarizer or circular polarizer can also be used.

[0128] For example, most electronic devices with a display screen, such as a personal computer or a smart phone with a liquid crystal display screen, emit linearly polarized light as outgoing light from the display screen, and therefore such electronic devices can be used as devices for providing linearly polarized light. More specifically, by bringing such electronic devices close to identification media, the identification media can be placed in an environment where the incidence of non-polarized ambient light is small and the incidence of outgoing light from the electronic device is relatively large, thereby achieving the supply of linearly polarized light.

[0129] As another example, electronic devices that have a display screen as part of a conventional personal computer or smart phone with a liquid crystal display screen emit circularly polarized light as outgoing light from the display screen, and thus such electronic devices can be used as devices for providing circularly polarized light. More specifically, by making such electronic devices approach identification media, the identification media can be placed in an environment where the incidence of non-polarized ambient light is small and the incidence of outgoing light from the electronic device is relatively large, thereby achieving the supply of circularly polarized light.

[0130] As another example, sometimes an additional film is attached to the display screen of the above-mentioned electronic device that emits linear polarized light or circular polarized light for various purposes. As examples of such additional films, films attached for various purposes such as protecting the display screen, adjusting the viewing angle of the display screen, and improving the viewing performance when observing the display screen through polarized sunglasses can be cited. Most of these films have a certain degree of phase difference, and therefore, can show the function of converting linear polarized light into circular polarized light or elliptically polarized light, and converting circular polarized light into linear polarized light or elliptically polarized light. Using an electronic device with an additional film in this manner, it is also possible to provide linear polarized light, circular polarized light, or elliptically polarized light in addition thereto.

[0131] Figure 5 and Figure 6 To schematically illustrate Figure 1 , Figure 2 and Figure 4 A side exploded view of another example of a method of using the identification medium 100 is shown.

[0132] exist Figure 5 In the example shown, the light incident on the identification medium 100 is linearly polarized light having a vibration direction in the X-axis direction. That is, the incident light A211(X) and A221(X) which are linearly polarized light having a vibration direction in the X-axis direction are incident on the layer 102(Xy) functioning as a λ / 4 wave plate and the isotropic layer 102(N) in the patterned phase difference layer 102, respectively.

[0133] The incident light A211(X) passes through the layer 102(Xy) and forms the light A212(L) as left-handed circularly polarized light, which is emitted downward and reaches the upper surface 101(R)U of the light reflecting layer 101(R). Since the light reflecting layer 101(R) is a right-handed reflective circular polarizer, the light A212(L) completely passes through the light reflecting layer 101(R) and forms the transmitted light A219(L). Therefore, the theoretical value of the brightness of the reflected light A213(n) in the light reflecting layer 101(R) is 0, and the theoretical value of the brightness of the light A214(n) that passes through the layer 102(Xy) again and is emitted from the display surface of the identification medium 100 is also 0.

[0134] On the other hand, the incident light A221(X) passes through the layer 102(N) and forms the linearly polarized light A222(X) which is emitted downward and reaches the upper surface 101(R)U of the light reflecting layer 101(R). The right circular polarization component in the light A222(X) is reflected to form the reflected light A223(R), whose theoretical brightness is half of the incident light. On the other hand, the left circular polarization component in the light A222(X) passes through the light reflecting layer 101(R) to form the transmitted light A229(L).

[0135] The light A223(R) transmits through the layer 102(N) again, becomes the light A224(R), and is emitted from the display surface of the identification medium 100. The theoretical value of the brightness of the light A224(R) is the same as that of the light A223(R).

[0136] As a result, when observing the identification medium 100 in a state where linearly polarized light having a vibration direction in the X-axis direction is incident, it is observed that the area occupied by layer 102 (Xy) is a relatively dark area with no reflected light, and on the other hand, it is observed that the area occupied by layer 102 (N) is a relatively bright area with reflected light having a brightness of 1 / 2 of the incident light.

[0137] Figure 6 To schematically illustrate the changes Figure 5 A side exploded view of an example of a method of using the identification medium of the present invention in the case of a relative angular relationship between the vibration direction of the identification medium and the incident linear polarized light in an example. Figure 6 The method of fixing the angle of the identification medium 100 relative to the coordinate axis and changing the angle of the vibration direction of the linear polarized light relative to the X-axis and the Y-axis is shown. However, in actual use, the relative angle relationship between the vibration direction of the identification medium and the incident linear polarized light can also be changed by moving the identification medium, moving the light source, replacing the light source, or combining two or more of these.

[0138] exist Figure 6 In the example of , as a result of changing the angle relationship, the light incident on the identification medium 100 is changed to be linearly polarized light having a vibration direction in the Y-axis direction. That is, the incident light A211 (Y) and A221 (Y) which are linearly polarized light having a vibration direction in the Y-axis direction respectively enter the layer 102 (Xy) and the layer 102 (N).

[0139] The incident light A211(Y) passes through the layer 102(Xy) and is formed as the right-handed circularly polarized light A212(R) which is emitted downward and reaches the upper surface 101(R)U of the light reflecting layer 101(R). Since the light reflecting layer 101(R) is a right-handed reflective circular polarizer, the light A212(R) is completely reflected in the light reflecting layer 101(R) to form the reflected light A213(R). The theoretical value of the brightness of the light A213(R) is the same as that of the light A212(R). On the other hand, the theoretical value of the brightness of the transmitted light A219(n) which passes through the light reflecting layer 101(R) is 0.

[0140] The light A213 (R) transmits through the layer 102 (Xy) again, becomes the light A214 (Y), and is emitted from the display surface of the identification medium 100. The theoretical value of the brightness of the light A214 (Y) is the same as that of the light A213 (R).

[0141] On the other hand, the incident light A221(Y) passes through the layer 102(N) and forms the linearly polarized light A222(Y) which is emitted downward and reaches the upper surface 101(R)U of the light reflecting layer 101(R). The right circular polarization component in the light A222(Y) is reflected to form the reflected light A223(R), and the theoretical value of the brightness thereof is half of the incident light. On the other hand, the left circular polarization component in the light A222(Y) passes through the light reflecting layer 101(R) to form the transmitted light A229(L).

[0142] The light A223(R) transmits through the layer 102(N) again, becomes the light A224(R), and is emitted from the display surface of the identification medium 100. The theoretical value of the brightness of the light A224(R) is the same as that of the light A223(R).

[0143] As a result, when observing the identification medium 100 in a state where linearly polarized light having a vibration direction in the Y-axis direction is incident, it is observed that the region occupied by the layer 102 (Xy) is a relatively bright region of reflected light having the same brightness as the incident light. On the other hand, it is observed that the region occupied by the layer 102 (N) is a region of reflected light having a brightness of 1 / 2 of the incident light. The brightness of the layer 102 (N) is relatively bright. Figure 5 There is no change from the situation shown, but in this example, layer 102 (N) is observed as a relatively dark area compared to the area occupied by layer 102 (Xy).

[0144] Therefore, by changing the relative angle relationship between the identification medium and the vibration direction of the linearly polarized light from Figure 5 In the example, the relationship is changed to Figure 6 , thereby changing the relative brightness between the multiple regions when observing using linearly polarized light as incident light. More specifically, when Figure 5When the vibration direction of the linear polarized light is rotated about an axis parallel to the Z-axis direction, the relative brightness of the area occupied by layer 102 (Xy) becomes brighter as the rotation angle increases, and the vibration direction of the linear polarized light reaches Figure 6 When the state is in the Y-axis direction, the relative brightness is maximum.

[0145] When such a brightness change is achieved in the entire visible region or a wide wavelength range close thereto, the brightness change can be observed as a change from black in a dark state to silver in a bright state. When the brightness change is achieved only in a wavelength range of a part of the visible region, the brightness change can be observed as a change in color corresponding to the wavelength range in which the change occurs.

[0146] On the other hand, when observing the identification medium 100 in a state where non-polarized light is incident without using the linear polarizer for observation, the observer observes Figure 1 , Figure 2 and Figure 4 The example shown in FIG. 1 shows the emitted light A114 (Y) and A124 (R). The observer cannot recognize the difference between them. In addition, even if the relative angle relationship between the identification medium 100 and the observer changes, the observer cannot recognize the change caused by the change in polarization state.

[0147] In the method of use of this example, the identification medium of the present invention can bring about a special effect, that is, the change in relative brightness can only be observed when linearly polarized light is used as the light source. Such a special effect cannot be obtained by using a replica that is easily obtained using conventional printing and other technologies. Therefore, the identification medium of the present invention exerts a high anti-counterfeiting performance in such use.

[0148] In addition, such a special effect can be obtained when observing linearly polarized light as incident light. Such observation can be achieved by visually identifying the medium in a state where an electronic device emitting linearly polarized light, such as a smartphone, is brought close to the display medium. Therefore, the identification medium of the present invention exerts a high identification function in such use.

[0149] In the above example, an example is shown in which the incident light is linearly polarized light (incident light A211(X) and incident light A221(X) and incident light A211(Y) and A221(Y)), but the present invention is not limited to this, and polarized light other than linear polarized light can also be used as the incident light.

[0150] As an example, right-handed circularly polarized light, left-handed circularly polarized light, or a combination thereof can be used as incident light instead of linearly polarized light. When right-handed circularly polarized light is used instead of incident light A211(X) and incident light A221(X), the brightness of the outgoing light from layer 102(Xy) and the outgoing light from layer 102(N) (relative theoretical values ​​when the brightness of the incident light is set to 100) are 50 and 100, respectively, and the isotropic layer 102(N) is observed as a relatively bright area.

[0151] On the other hand, when left-handed circularly polarized light is used instead of incident light A211(X) and incident light A221(X), the brightness of the outgoing light from layer 102(Xy) and the outgoing light from layer 102(N) are 50 and 0, respectively, and layer 102(Xy) functioning as a λ / 4 wave plate is observed as a relatively bright area.

[0152] Therefore, by comparing two or more of the observation of incident non-polarized light, the observation of incident right-handed circularly polarized light, and the observation of incident left-handed circularly polarized light, the identification function can be displayed based on the change in relative brightness caused thereby. Since some electronic devices such as smartphones equipped with a certain protective film also have electronic devices that emit circularly polarized light, such observation can be achieved by visually identifying the medium in a state where such an electronic device that emits circularly polarized light is brought close to the display medium.

[0153] [Identification medium: Embodiment 2]

[0154] exist Figure 1-2 and Figures 4 to 6 In the example, an identification medium 100 is illustrated, which has a reflective circular polarizer as a light reflecting layer, and a layer in which a part of the layer functions as a λ / 4 wave plate as a patterned phase difference layer. However, the identification medium of the present invention is not limited to this, and can have a structure other than this. For example, in the identification medium of the present invention, a reflective linear polarizer can be provided as a light reflecting layer, and a layer in which a part of the layer functions as a λ / 2 wave plate as a patterned phase difference layer. Figure 7 to Figure 10 , an example of this is described below.

[0155] Figure 7 FIG. 1 is a side exploded view schematically showing another example of the identification medium and method of use of the present invention. Figure 7In the example, the identification medium 200 has a light reflection layer 201 (Y) and a patterned phase difference layer 202. In this example, the entire area of ​​the upper surface 201 (Y)U of the light reflection layer 201 (Y) is an area corresponding to the display surface, and the patterned phase difference layer 202 occupying the entire area is provided. Only a part of the patterned phase difference layer 202 is a layer 202 (Xy) that functions as a λ / 2 wave plate, and the other part is an isotropic layer 202 (N).

[0156] In the identification medium 200, the upper surface 202U of the patterned phase difference layer 202 functions as a display surface. That is, part of the light incident on the surface 202U of the identification medium 200 is reflected in the identification medium 200 and emitted from the surface 202U, and the observer observes the emitted light, thereby demonstrating the function as an identification medium.

[0157] exist Figure 7 In the example of FIG. 2 , a reflective linear polarizer whose transmission axis is positioned in the Y-axis direction is used as the light reflecting layer 201(Y). That is, the light reflecting layer 201(Y) transmits the linear polarization component having a vibration direction in the Y-axis direction among the light incident on its upper surface 201(Y)U, and reflects the linear polarization component having a vibration direction in the X-axis direction.

[0158] exist Figure 7 In the example of , the patterned phase difference layer 202 is a combination of a layer 202 (Xy) functioning as a λ / 2 wave plate and an isotropic layer 202 (N) arranged side by side in the horizontal direction. Therefore, the area occupied by the layer 202 (Xy) occupies a part of the display surface of the identification medium 200. The layer 202 (Xy) has a slow axis in the Xy direction.

[0159] [Method of using the identification medium according to Embodiment 2: Part 1]

[0160] exist Figure 7 , an example is shown in which the light incident on the identification medium 200 is non-polarized light, and the reflected light from the identification medium 200 is observed through the observation linear polarizer 191 (X). Figure 1-2 The observation linear polarizer shown is the same as that of the identification medium 200, and is a polarizer that is positioned at a relative angle to the identification medium 200 so as to have a transmission axis in the X-axis direction. Therefore, in this example, the slow axis of the layer 202 (Xy) is deflected 45° counterclockwise relative to the transmission axis of the observation linear polarizer 191 (X). In addition, the transmission axis of the light reflecting layer 201 (Y) is perpendicular to the transmission axis of the observation linear polarizer 191 (X).

[0161] exist Figure 7In the illustrated example of use of the identification medium 200 , incident light A311 (N) and A321 (N) as non-polarized light are incident on the layer 202 (Xy) functioning as a λ / 2 wave plate and the isotropic layer 202 (N) in the patterned phase difference layer 202 , respectively.

[0162] The incident light A311(N) passes through the layer 202(Xy) and forms the light A312(N) as non-polarized light, which is emitted downward and reaches the upper surface 201(Y)U of the light reflecting layer 201(Y). The light reflecting layer 201(Y) is a reflective linear polarizer with the transmission axis positioned in the Y-axis direction, so the linear polarization component with the vibration direction in the X-axis direction in the light A312(N) is reflected to form reflected light A313(X), and the theoretical value of its brightness is half of the incident light. On the other hand, the linear polarization component with the vibration direction in the Y-axis direction in the light A312(N) passes through the light reflecting layer 201(Y) to form transmitted light A319(Y).

[0163] Light A313 (X) transmits layer 202 (Xy) again to form light A314 (Y), which is emitted from the display surface of the identification medium 200. Since light A313 (X) is linearly polarized light having a vibration direction in the X-axis direction, and layer 202 (Xy) is a λ / 2 wave plate having a slow axis in the XY directions, light A314 (Y) becomes linearly polarized light having a polarization direction in the Y-axis direction, and the theoretical value of its brightness is the same as that of light A313 (X).

[0164] When the emitted light A314(Y) is incident on the observation linear polarizer 191(X), the vibration direction of the polarized light of the light A314(Y) is perpendicular to the transmission axis of the observation linear polarizer 191(X), so the light A314(Y) is completely blocked, and the theoretical value of the brightness of the emitted light A315(n) from the observation linear polarizer 191(X) is 0.

[0165] On the other hand, the incident light A321(N) passes through the layer 202(N) and is emitted downward as non-polarized light A322(N) to reach the upper surface 201(Y)U of the light reflecting layer 201(Y). The linear polarization component of the light A322(N) having a vibration direction in the X-axis direction is reflected to form reflected light A323(X), and the theoretical value of its brightness is half of the incident light. On the other hand, the linear polarization component of the light A322(N) having a vibration direction in the Y-axis direction passes through the light reflecting layer 201(Y) to form transmitted light A329(Y).

[0166] The light A323 (X) transmits through the layer 202 (N) again, becomes the light A324 (X), and is emitted from the display surface of the identification medium 100. The theoretical value of the brightness of the light A324 (X) is the same as that of the light A323 (X).

[0167] When the emitted light A324(X) enters the observation linear polarizer 191(X), the polarization vibration direction of the light A324(X) is parallel to the transmission axis of the observation linear polarizer 191(X), so the light A324 becomes the emitted light A325(X) and is emitted from the observation linear polarizer 191(X). The theoretical value of the brightness of the emitted light A325(X) is the same as that of the light A324(X).

[0168] As a result, when observing the identification medium 200 in a state where non-polarized light is incident through the linear polarizer 191 (X), it is observed that the area occupied by the layer 202 (Xy) is a relatively dark area with no reflected light, and on the other hand, it is observed that the area occupied by the layer 202 (N) is a relatively bright area with reflected light having a brightness of 1 / 2 of the incident light.

[0169] Figure 8 To schematically illustrate the changes Figure 7 An exploded side view of an example of a method of using the identification medium of the present invention in the case of a relative angle relationship between the identification medium and the observation linear polarizer in the example. Figure 8 , the angle of the identification medium 200 relative to the coordinate axis is fixed, and the angle of the observation linear polarizer relative to the X-axis and the Y-axis is changed. However, in actual use, the relative angle relationship between the identification medium and the observation linear polarizer can be changed by moving the identification medium, moving the observation linear polarizer, replacing the observation linear polarizer, or combining two or more of these.

[0170] exist Figure 8 In the example of , as a result of changing the angle relationship, the observation linear polarizer 191 (Y) is used as the observation polarizer. The observation linear polarizer 191 (Y) is a polarizer that is positioned at a relative angle with the identification medium 200 so as to have a transmission axis in the Y-axis direction. Therefore, in this example, the slow axis of the layer 202 (Xy) is deflected 45° clockwise relative to the transmission axis of the observation linear polarizer 191 (Y).

[0171] exist Figure 8 In the example of use of the identification medium 200 shown in FIG. 1 , incident light A311(N) and A321(N) as non-polarized light are incident on the layer 202(Xy) and the isotropic layer 202(N) functioning as a λ / 2 wave plate in the patterned phase difference layer 202, respectively, and a portion of each of them is emitted from the display surface of the identification medium 200 as light A314(Y) and A324(X), respectively. The path of light so far is similar to that of FIG. Figure 7 Same as the example.

[0172] When the emitted light A314 (Y) enters the observation linear polarizer 191 (Y), since the polarization vibration direction of the light A314 (Y) is parallel to the transmission axis of the observation linear polarizer 191 (Y), the light A314 (Y) is completely transmitted to form the emitted light A315 (Y), which is emitted from the observation linear polarizer 191 (Y). The theoretical value of the brightness of the emitted light A315 (Y) is the same as that of the light A314 (Y).

[0173] On the other hand, when the emitted light A324(X) is incident on the observation linear polarizer 191(Y), since the vibration direction of the polarized light of the light A324(X) is perpendicular to the transmission axis of the observation linear polarizer 191(Y), the light A324(X) is completely blocked and the theoretical value of the brightness of the emitted light A325(n) from the observation linear polarizer 191(Y) is 0.

[0174] As a result, when observing the identification medium 200 in a state where non-polarized light is incident through the observation linear polarizer 191 (Y), the area occupied by the layer 202 (Xy) is observed to be a relatively bright area of ​​reflected light having a brightness of 1 / 2 of the incident light. On the other hand, the area occupied by the layer 102 (N) is observed to be a relatively dark area without reflected light.

[0175] Therefore, by changing the relative angle between the identification medium and the observation linear polarizer from Figure 7 In the example, the relationship is changed to Figure 8 , thereby changing the relative brightness between the multiple regions when observing through the linear polarizer. More specifically, when Figure 7 When the state of the observation linear polarizer 191 (X) is changed, the direction of the observation linear polarizer is rotated around an axis parallel to the Z-axis direction. As the rotation angle increases, the relative brightness of the area occupied by the layer 202 (Xy) becomes brighter. When the direction of the observation linear polarizer reaches Figure 8 When the linear polarizer 191 (Y) is in the observation state, the relative brightness is maximum.

[0176] When such a brightness change is achieved in the entire visible region or a wide wavelength range close thereto, the brightness change can be observed as a change from black in a dark state to silver in a bright state. When the brightness change is achieved only in a wavelength range of a part of the visible region, the brightness change can be observed as a change in color corresponding to the wavelength range in which the change occurs.

[0177] On the other hand, when observing the state of non-polarized light incident on the identification medium 200 without using a linear polarizer, the observer observes the outgoing light A314 (Y) and A324 (X). The outgoing light A314 (Y) and A324 (X) have different polarization states, but the same brightness. Since human vision cannot recognize the difference in the polarization state, the observer cannot recognize the difference between them. In addition, even if the relative angle relationship between the identification medium 200 and the observer changes, the observer cannot recognize the changes caused by the change in the polarization state.

[0178] In the method of use of this example, the identification medium of the present invention can bring about a special effect, that is, the change in relative brightness can be observed only when the linear polarizer is used for observation. In addition, such a special effect can be obtained when non-polarized light is used as incident light and the linear polarization component of the reflected light is selectively observed, and the observation can be easily performed as described above. Therefore, the identification medium of the present invention exerts high anti-counterfeiting performance and high identification function in such use.

[0179] [Method of using the identification medium according to Embodiment 2: Part 2]

[0180] The above example is an example of a method of using non-polarized light as the light incident on the identification medium 200. On the other hand, an example of a method of using linearly polarized light as the light incident on the identification medium 200 will be described below.

[0181] When the incident light is linearly polarized light, the reflected light can be directly observed visually without using a linear polarizer for observation. Figure 5 and Figure 6 The method is the same as that in the described embodiment 1.

[0182] Fig. 9 and Fig.10 To schematically illustrate Figure 7 and Figure 8 A side exploded view of another example of a method of using the identification medium 200 is shown.

[0183] exist Fig. 9 In the example shown, the light incident on the identification medium 200 is linearly polarized light having a vibration direction in the X-axis direction. That is, the incident light A411(X) and A421(X) which are linearly polarized light having a vibration direction in the X-axis direction are incident on the layer 202(Xy) functioning as a λ / 2 wave plate and the isotropic layer 202(N) in the patterned phase difference layer 202, respectively.

[0184] The incident light A411(X) passes through the layer 202(Xy) and forms the light A412(Y) which is linearly polarized light having a vibration direction in the Y-axis direction, and then is emitted downward and reaches the upper surface 201(Y)U of the light reflecting layer 201(Y). Since the light reflecting layer 201(Y) is a reflective linear polarizer with a transmission axis positioned in the Y-axis direction, the light A412(Y) is completely transmitted through the light reflecting layer 201(Y) to form the transmitted light A419(Y). Therefore, the theoretical value of the brightness of the reflected light A413(n) in the light reflecting layer 201(Y) is 0, and the theoretical value of the brightness of the light A414(n) which passes through the layer 202(Xy) again and is emitted from the display surface of the identification medium 200 is also 0.

[0185] On the other hand, the incident light A421(X) passes through the layer 202(N) and forms the linearly polarized light A422(X) which is emitted downward and reaches the upper surface 201(Y)U of the light reflecting layer 201(Y). Since the light reflecting layer 201(Y) is a reflective linear polarizer with the transmission axis positioned in the Y-axis direction, the light A422(X) is completely reflected by the light reflecting layer 201(Y) to form reflected light A423(X). The theoretical value of the brightness of the light A423(X) is the same as that of the light A422(X). On the other hand, the theoretical value of the brightness of the transmitted light A429(n) which passes through the light reflecting layer 201(Y) is 0.

[0186] The light A423 (X) transmits through the layer 202 (N) again, becomes the light A424 (X), and is emitted from the display surface of the identification medium 200. The theoretical value of the brightness of the light A424 (X) is the same as that of the light A423 (X).

[0187] As a result, when observing the identification medium 200 in a state where linear polarized light having a vibration direction in the Y-axis direction is incident, it is observed that the area occupied by the layer 202 (Xy) is a relatively dark area with no reflected light. On the other hand, it is observed that the area occupied by the layer 202 (N) is a relatively bright area with reflected light having the same brightness as the incident light.

[0188] Fig.10 To schematically illustrate the changes Fig. 9 A side exploded view of an example of a method of using the identification medium of the present invention in the case of a relative angular relationship between the vibration direction of the identification medium and the incident linear polarized light in an example. Fig.10 The method of fixing the angle of the identification medium 200 relative to the coordinate axis and changing the angle of the vibration direction of the linear polarized light relative to the X-axis and the Y-axis is shown. However, in actual use, the change of these relative angle relationships can also be performed by moving the identification medium, moving the light source, replacing the light source, or combining two or more of these.

[0189] exist Fig.10In the example of , as a result of changing the angle relationship, the light incident on the identification medium 200 is changed to be linearly polarized light having a vibration direction in the Y-axis direction. That is, the incident light A411 (Y) and A421 (Y) which are linearly polarized light having a vibration direction in the Y-axis direction are incident on the layer 202 (Xy) and the layer 202 (N), respectively.

[0190] The incident light A411(Y) passes through the layer 202(Xy) and forms the light A412(X) which is linearly polarized light having a vibration direction in the X-axis direction, and then is emitted downward and reaches the upper surface 201(Y)U of the light reflecting layer 201(Y). Since the light reflecting layer 201(Y) is a reflective linear polarizer with the transmission axis positioned in the Y-axis direction, the light A412(X) is completely reflected in the light reflecting layer 201(Y) to form the reflected light A413(X). The theoretical value of the brightness of the light A413(X) is the same as that of the light A412(X). On the other hand, the theoretical value of the brightness of the transmitted light A419(n) passing through the light reflecting layer 201(Y) is 0.

[0191] The light A413 (X) transmits through the layer 202 (Xy) again, becomes the light A414 (Y), and is emitted from the display surface of the identification medium 200. The theoretical value of the brightness of the light A414 (Y) is the same as that of the light A413 (X).

[0192] On the other hand, the incident light A421(Y) passes through the layer 202(N) and forms the linearly polarized light A422(Y) which is emitted downward and reaches the upper surface 201(Y)U of the light reflecting layer 201(Y). Since the light reflecting layer 201(Y) is a reflective linear polarizer whose transmission axis is positioned in the Y-axis direction, the light A422(Y) is completely transmitted through the light reflecting layer 201(Y) to form the transmitted light A429(Y). Therefore, the theoretical value of the brightness of the reflected light A423(n) in the light reflecting layer 201(Y) is 0, and the theoretical value of the brightness of the light A424(n) which passes through the layer 202(Xy) again and is emitted from the display surface of the identification medium 200 is also 0.

[0193] As a result, when observing the identification medium 200 in a state where linear polarized light having a vibration direction in the Y-axis direction is incident, it is observed that the region occupied by the layer 202 (Xy) is a relatively bright region of reflected light having the same brightness as the incident light. On the other hand, it is observed that the region occupied by the layer 202 (N) is a relatively dark region without reflected light.

[0194] Therefore, by changing the relative angle relationship between the identification medium and the vibration direction of the linearly polarized light from Fig. 9 In the example, the relationship is changed to Fig.10 , thereby changing the relative brightness between the multiple regions when observing using linearly polarized light as incident light. More specifically, when Fig. 9When the vibration direction of the linear polarized light is rotated about an axis parallel to the Z-axis direction, the relative brightness of the area occupied by layer 202 (Xy) becomes brighter as the rotation angle increases, and the vibration direction of the linear polarized light reaches Fig.10 When the state is in the Y-axis direction, the relative brightness is maximum.

[0195] When such a brightness change is achieved in the entire visible region or a wide wavelength range close thereto, the brightness change can be observed as a change from black in a dark state to silver in a bright state. When the brightness change is achieved only in a wavelength range of a part of the visible region, the brightness change can be observed as a change in color corresponding to the wavelength range in which the change occurs.

[0196] On the other hand, when observing the identification medium 200 in a state where non-polarized light is incident without using the observation linear polarizer, the observer observes Figure 7 and Figure 8 The example shown in FIG. 1 shows the emitted light A314 (Y) and A324 (X). The observer cannot recognize the difference between them. In addition, even if the relative angle relationship between the identification medium 200 and the observer changes, the observer cannot recognize the change caused by the change in polarization state.

[0197] In the method of use of this example, the identification medium of the present invention can bring about a special effect, that is, only when linear polarized light is used as the light source, the change in relative brightness can be observed. Such a special effect cannot be obtained by using a replica that is easily obtained using conventional printing and other technologies. In addition, such a special effect can also be obtained when observing with linear polarized light as the incident light, and the observation can be easily performed as described above. Therefore, the identification medium of the present invention exerts a high anti-counterfeiting performance and a high identification function in such use.

[0198] [Specific examples of light reflecting layer]

[0199] The light reflecting layer is a layer that reflects incident light into circularly polarized light or linearly polarized light. Examples of the light reflecting layer include the reflective circular polarizer exemplified by the light reflecting layer 101 (R) and the reflective linear polarizer exemplified by the light reflecting layer 201 (Y). In addition, the light reflecting layer may exhibit such a function by only one layer or by a combination of multiple layers.

[0200] As an example of a reflective circular polarizer, a layer of a material with cholesteric regularity can be cited. Cholesteric regularity refers to the following structure: on a certain plane inside the material, the molecular axis is arranged in a certain direction, on the next plane overlapping it, the direction of the molecular axis is deflected at a small angle, and on the next plane, it is further deflected at a small angle. As the planes arranged in this way are successively passed through, the angles of the molecular axes in the plane are successively deflected (twisted). That is, in the case where the molecules inside a layer of a certain material have cholesteric regularity, the molecules are arranged in a certain direction on a first plane inside the layer. In the next second plane inside the layer that overlaps with the first plane, the direction of the molecular axis is deflected at a small angle compared to the direction of the molecular axis in the first plane. In the next third plane that further overlaps with the second plane, the direction of the molecular axis is further deflected at a small angle compared to the direction of the molecular axis in the second plane. In the planes arranged in an overlapping manner like this, the angles of the molecular axes in the plane are successively deflected (twisted). A structure in which the direction of the molecular axis is gradually twisted like this is usually a helical structure, which is an optical chiral structure.

[0201] As a more specific example of a material having cholesteric regularity, a cholesteric resin layer can be cited. A cholesteric resin layer refers to a layer obtained by curing a curable liquid crystal compound exhibiting a cholesteric liquid crystal phase. The cholesteric resin layer can be obtained, for example, by polymerizing a polymerizable liquid crystal compound in a state exhibiting a cholesteric liquid crystal phase. More specifically, a liquid crystal composition containing a polymerizable liquid crystal compound can be coated on a suitable substrate, etc., to form a layer, and the cholesteric liquid crystal phase is oriented and cured, thereby obtaining a cholesteric resin layer.

[0202] As a polymerizable liquid crystal compound, a photopolymerizable liquid crystal compound is preferred. As a photopolymerizable liquid crystal compound, a photopolymerizable liquid crystal compound that can be polymerized by irradiating active energy rays can be used. As active energy rays, energy rays that can cause the polymerization reaction of the photopolymerizable liquid crystal compound can be used from a wide range of energy rays such as visible light, ultraviolet rays, and infrared rays, and ionizing radiation such as ultraviolet rays is particularly preferred. Among them, as a photopolymerizable liquid crystal compound preferably used in a cholesteric liquid crystal composition, a rod-shaped liquid crystal compound having two or more reactive groups in one molecule is preferred, and a compound represented by formula (1) is particularly preferred.

[0203] R 3 -C 3 -D 3 -C 5 -MC 6 -D 4 -C 4 -R 4 Formula (1)

[0204] In formula (1), R 3 and R 4 are reactive groups, each independently selected from (meth)acryloyl, (thio)epoxy, oxetanyl, thietanyl, aziridine, pyrrolyl, vinyl, allyl, fumarate, cinnamoyl, The reactive groups include oxazoline, mercapto, iso(thio)cyanate, amino, hydroxyl, carboxyl, and alkoxysilyl. When the liquid crystal composition is cured, a liquid crystal composition cured layer having high mechanical strength can be obtained.

[0205] In formula (1), D 3 and D 4 Each independently represents a group selected from the group consisting of a single bond, a linear or branched alkyl group having 1 to 20 carbon atoms, and a linear or branched alkylene oxide group having 1 to 20 carbon atoms.

[0206] In formula (1), C 3 ~C 6 Each independently represents a group selected from a single bond, -O-, -S-, -SS-, -CO-, -CS-, -OCO-, -CH2-, -OCH2-, -CH=NN=CH-, -NHCO-, -O-(C=O)-O-, -CH2-(C=O)-O-, and -CH2O-(C=O)-.

[0207] In formula (1), M represents a mesogenic group. Specifically, M represents an unsubstituted or substituted azomethine, azoxy, phenyl, biphenyl, terphenyl, naphthalene, anthracene, benzoate, cyclohexanecarboxylic acid phenyl ester, cyanophenylcyclohexane, cyano substituted phenyl pyrimidine, alkoxy substituted phenyl pyrimidine, phenyl diphenyl ester, A group in which two to four skeletons which are the same or different from each other in alkanes, tolans, and alkenylcyclohexylbenzonitriles are bonded to bonding groups such as -O-, -S-, -SS-, -CO-, -CS-, -OCO-, -CH2-, -OCH2-, -CH=NN=CH-, -NHCO-, -O-(C=O)-O-, -CH2-(C=O)-O-, and -CH2O-(C=O)-.

[0208] Examples of the substituent that the mesogenic group M may have include a halogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, a cyano group, a nitro group, an -OR 5 、-OC(=O)-R 5 、-C(=O)-OR 5 、-OC(=O)-OR5 、-NR 5 -C(=O)-R 5 、-C(=O)-NR 5 R 7 , or -OC(=O)-NR 5 R 7 Here, R 5 and R 7 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. 5 and R 7 In the case of an alkyl group, -O-, -S-, -OC(=O)-, -C(=O)-O-, -OC(=O)-O-, -NR 6 -C(=O)-, -C(=O)-NR 6 -、-NR 6 -, or -C(=O)- (excluding the case where two or more -O- are inserted adjacently and two or more -S- are inserted adjacently). 6 It represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0209] As the substituent in the above-mentioned “alkyl group having 1 to 10 carbon atoms which may have a substituent”, there can be mentioned, for example, a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkoxy group having 2 to 8 carbon atoms, an alkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylcarbonyloxy group having 2 to 7 carbon atoms, an alkoxycarbonyloxy group having 2 to 7 carbon atoms, and the like.

[0210] In addition, the rod-like liquid crystal compound preferably has an asymmetric structure. Here, the asymmetric structure means that in formula (1), the mesogenic group M is the center and R 3 -C 3 -D 3 -C 5 -M- vs. -MC 6 -D 4 -C 4 -R 4 Different structures: By using a rod-like liquid crystal compound having an asymmetric structure as the rod-like liquid crystal compound, the alignment uniformity can be further improved.

[0211] Preferred specific examples of the rod-like liquid crystal compound include the following compounds (B1) to (B10). However, the rod-like liquid crystal compound is not limited to the following compounds.

[0212] [Chemical formula 1]

[0213]

[0214] [Chemical formula 2]

[0215]

[0216] When the liquid crystal composition contains the above-mentioned rod-like liquid crystal compound, the liquid crystal composition preferably contains a compound represented by formula (2) as an alignment aid in combination with the rod-like liquid crystal compound.

[0217] R 1 -A 1 -BA 2 -R 2 (2)

[0218] In formula (2), R 1 and R 2 Each is independently a group selected from a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkylene oxide group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a (meth)acryloyl group into which any bonding group may be inserted, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group.

[0219] The above-mentioned alkyl and epoxyalkyl groups are unsubstituted or may be substituted with one or more halogen atoms. Furthermore, the above-mentioned halogen atoms, hydroxyl groups, carboxyl groups, (meth)acryloyl groups, epoxy groups, mercapto groups, isocyanate groups, amino groups, and cyano groups may be bonded to alkyl groups having 1 to 2 carbon atoms and epoxyalkyl groups.

[0220] As R 1 and R 2 Preferred examples of the group include a halogen atom, a hydroxyl group, a carboxyl group, a (meth)acryloyl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group.

[0221] In addition, R 1 and R 2 At least one of them is preferably a reactive group. 1 and R 2 At least one of the above-mentioned reactive groups has a reactive group, and the compound represented by the above-mentioned formula (2) is fixed in the liquid crystal composition cured layer during curing, and a more solid layer can be formed. Here, the reactive group can include, for example, a carboxyl group, a (meth)acryloyl group, an epoxy group, a mercapto group, an isocyanate group, and an amino group.

[0222] In formula (2), A 1 and A 2Each independently represents a group selected from 1,4-phenylene, 1,4-cyclohexylene, cyclohexene-1,4-ene, 4,4'-biphenylene, 4,4'-bicyclohexylene, and 2,6-naphthylene. The above-mentioned 1,4-phenylene, 1,4-cyclohexylene, cyclohexene-1,4-ene, 4,4'-biphenylene, 4,4'-bicyclohexylene, and 2,6-naphthylene are unsubstituted or may be substituted with one or more halogen atoms, hydroxyl groups, carboxyl groups, cyano groups, amino groups, alkyl groups having 1 to 10 carbon atoms, halogenated alkyl groups, etc. In A 1 and A 2 When two or more substituents are present in each of the above compounds, these substituents may be the same as or different from each other.

[0223] As A 1 and A 2 Particularly preferred groups include groups selected from 1,4-phenylene, 4,4'-biphenylene, and 2,6-naphthylene. These aromatic ring skeletons are relatively rigid compared to alicyclic skeletons, have high affinity with the mesogen of the rod-like liquid crystal compound, and further improve the alignment uniformity.

[0224] In formula (2), B is selected from a single bond, -O-, -S-, -SS-, -CO-, -CS-, -OCO-, -CH2-, -OCH2-, -CH=NN=CH-, -NHCO-, -O-(C=O)-O-, -CH2-(C=O)-O-, and -CH2O-(C=O)-.

[0225] Particularly preferred groups for B include a single bond, -O-(C=O)-, and -CH=NN=CH-.

[0226] Particularly preferred specific examples of the compound represented by formula (2) include the following compounds (A1) to (A10). These may be used alone or in combination of two or more in any ratio.

[0227] [Chemical formula 3]

[0228]

[0229] In the above compound (A3), "*" represents a chiral center.

[0230] The weight ratio represented by (total weight of compounds represented by formula (2)) / (total weight of rod-like liquid crystal compounds) is preferably 0.001 or more, more preferably 0.01 or more, further preferably 0.05 or more, preferably 1 or less, and more preferably 0.65 or less. By making the above-mentioned weight ratio above the above-mentioned lower limit, the orientation uniformity can be improved in the layer of the liquid crystal composition. In addition, by making the above-mentioned weight ratio below the upper limit, the orientation uniformity can be improved. In addition, the stability of the liquid crystal phase of the liquid crystal composition can be improved. Furthermore, since the refractive index anisotropy Δn of the liquid crystal composition can be improved, a liquid crystal composition cured layer having desired optical properties such as selective reflection performance of circularly polarized light can be stably obtained. Here, the total weight of the compounds represented by formula (2) represents the weight of the compound when only one compound represented by formula (2) is used, and represents the total weight when two or more are used. Similarly, the total weight of the rod-like liquid crystal compounds represents the weight of the compound when only one rod-like liquid crystal compound is used, and represents the total weight when two or more are used.

[0231] Furthermore, when the compound represented by formula (2) is used in combination with a rod-like liquid crystal compound, the molecular weight of the compound represented by formula (2) is preferably less than 600, and the molecular weight of the rod-like liquid crystal compound is preferably not less than 600. Thus, the compound represented by formula (2) can enter the gap between the rod-like liquid crystal compounds having a larger molecular weight than the compound represented by formula (2), thereby improving the alignment uniformity.

[0232] The liquid crystal composition for forming a cholesteric resin layer can also include any component constituting the cholesteric resin layer, and a solvent for facilitating the processing of the liquid crystal composition. As examples of any component, a chiral agent, a polymerization initiator, and a surfactant can be cited. As specific examples of any component and solvent, any component and solvent described in Japanese Patent Publication No. 2019-188740 can be cited.

[0233] Examples of the reflective linear polarizer include a film obtained by laminating a plurality of thin films (for example, trade name "DBEF", manufactured by 3M Co.) and a wire grid polarizer.

[0234] In the case where the light reflecting layer is any one of a reflective circular polarizer and a reflective linear polarizer, the maximum reflectivity of the non-polarized light incident on the light reflecting layer is 50%. The light reflecting layer visually presents various colors according to the reflection band and the reflectivity. In the case where the reflectivity of the non-polarized light incident on the light reflecting layer is 35-50% of all wavelengths in the wavelength range of 420nm to 650nm, the light reflecting layer is observed to be a silver layer. In the case where the band forming the reflection of 35-50% is narrower than the above wavelength range, the light reflecting layer can present various colors according to the band. For example, in the case of the reflection band near 450nm, in the case of near 550nm, and in the case of near 650nm, the colors such as blue, green, and red can be presented respectively.

[0235] In the identification medium of the present invention, the light reflecting layer may be composed of only one layer or multiple layers. In addition, the identification medium may be composed of only one layer or multiple layers having different polarization states of reflected light. For example, in the identification medium, slices of multiple reflective polarizers showing multiple colors such as red, green, blue, and silver may be arranged in a large number in the horizontal direction as the light reflecting layer. In this way, when multiple slices are used as the light reflecting layer, the light reflecting layer is preferably a reflective circular polarizer. In accordance with Figure 1 to Figure 6 In the case of using a reflective circular polarizer according to the principle shown, since the reflective circular polarizer does not need to be oriented in a certain direction, the direction of brightening can be specified only by the slow axis of the phase difference layer. Therefore, even if the reflective circular polarizer is made into tiny slices and is not arranged in a uniform direction in the identification medium, an identification medium that exerts the effect of the present invention can be easily constructed.

[0236] From the viewpoint of clearly viewing the latent image, the light reflecting layer is preferably a silver light reflecting layer, or a combination of a silver light reflecting layer and a light reflecting layer of another color.

[0237] [Specific example of patterned phase difference layer]

[0238] The patterned phase difference layer is a layer including a region having a phase difference. The region having a phase difference occupies a part of the display surface area in the identification medium.

[0239] As examples of a phase difference layer (the portion of a patterned phase difference layer having a phase difference), there can be cited a region functioning as a λ / 4 wave plate as exemplified in the above-mentioned layer 102 (Xy), and a region functioning as a λ / 2 wave plate as exemplified in the above-mentioned layer 202 (Xy).

[0240] As the material constituting the phase difference layer, various solid materials with optical anisotropy can be cited. As one example thereof, a stretched film obtained by stretching a transparent material can be cited. More specifically, a film in which an optically isotropic film is stretched and given an in-plane delay Re that can function as a λ / 4 wave plate or a λ / 2 wave plate can be cited. From the viewpoint of being relatively cheap to obtain, easy to give a desired value of Re and being formed into a desired arbitrary shape, a stretched film is preferred.

[0241] As another example of a material constituting a phase difference layer, a solidified material of a liquid crystal compound can be cited. Specifically, a layer obtained by curing a curable liquid crystal compound oriented in the following liquid crystal state, wherein the liquid crystal state is a liquid crystal state that exhibits a phase difference that can function as a λ / 4 wave plate or a λ / 2 wave plate. As an example of such a layer and a method for manufacturing the same, a layer and a method for manufacturing the same described in International Publication No. 2019 / 116995 can be cited. Since the solidified material of the liquid crystal compound can easily form a film in which a part thereof has a different phase difference from another part, it is particularly preferred when a film needs to be formed as a patterned phase difference layer.

[0242] As a preferred example, the identification medium can have one or more independent patterned phase difference layers as patterned phase difference layers. Here, the independent patterned phase difference layer refers to a component consisting of an area having a size smaller than the display surface of the identification medium and having a certain phase difference. By configuring the independent patterned phase difference layer in the display surface of the identification medium, the area where the independent patterned phase difference layer exists can function as an area with a phase difference, and the other areas can function as isotropic areas.

[0243] In the display surface of one identification medium, the region with phase difference in the patterned phase difference layer may be only one or more. In the case of having more than one region with phase difference, the slow axis directions thereof may be the same direction or different directions.

[0244] In the case where the identification medium has multiple regions with different slow axis directions as regions with phase difference, the resulting design effect can be obtained. Specifically, when the relative angle relationship between the identification medium and the observation linear polarizer or the relative angle relationship between the identification medium and the vibration direction of the incident linear polarized light is changed, a design effect in which multiple regions become brighter one by one can be obtained. In addition, the identification medium can be constructed in a manner in which any one of the multiple regions is the brightest in multiple orientations, so there are no restrictions on the orientation of the identification medium and the orientation of the observation linear polarizer, and an identification medium in which a latent image can be observed from any angle can be constructed. Such an effect cannot be obtained by using articles that are easily obtained using conventional printing and other technologies, and can be viewed as a characteristic property of a true identification medium. Therefore, in this case, the anti-counterfeiting performance and identification function of the identification medium can be particularly improved. The slow axis directions of multiple regions can be in regularly different states or irregularly different states.

[0245] As an example of a method for constituting multiple regions with different slow axis directions as regions with phase difference, the following method can be cited: prepare multiple independent patterned phase difference layers, and arrange them in a display surface of an identification medium in a state where the slow axis directions are different from each other. By such a method, it is possible to easily constitute multiple regions with different slow axis directions. In addition, by such a method, it is possible to easily make the slow axis directions of multiple regions irregularly different. More specifically, multiple independent patterned phase difference layers are prepared, and they are randomly placed or sprinkled on the light reflecting layer, thereby achieving such irregularly different slow axis configurations. By constituting such irregularly different slow axis configurations, when the relative angle relationship between the identification medium and the observation linear polarizer or the relative angle relationship between the identification medium and the vibration direction of the incident linear polarized light is changed, a design effect in which multiple regions are brightened one by one in a random order can be obtained. Thus, the anti-counterfeiting performance and identification function of the identification medium, as well as the design value, can be further improved.

[0246] When a plurality of regions having different slow axis directions are formed as regions having a phase difference, it is preferred that the combination of the light reflecting layer and the patterned phase difference layer is a combination of a reflective circular polarizer and a phase difference layer including a region functioning as a λ / 4 wave plate. In this case, since there is no need to adjust the relative orientation of the slow axis direction of the patterned phase difference layer and the light reflecting layer, the slow axis directions of the plurality of regions can be easily set to any direction.

[0247] [Any structural element]

[0248] The identification medium of the present invention may include any structural element in addition to the light reflecting layer and the patterned phase difference layer. Examples of the arbitrary structural element include a light absorbing layer, a diffusion layer, a high phase difference layer, an embedding transparent resin, a decorative member, and a mounting member.

[0249] The light absorbing layer is a layer that absorbs incident light. The light absorbing layer can be a black layer. The material of the light absorbing layer can be any material, and can be, for example, a film dyed black. The light absorbing layer can be arranged on the back side of the light reflecting layer, that is, at a position of the light reflecting layer that is opposite to the viewing side. In the case where the light reflecting layer is any one of a reflective circular polarizer and a reflective linear polarizer, most of the incident light that is not reflected is transmitted. When the light absorbing layer is arranged on the back side of the light reflecting layer, the transmitted light is absorbed, and as a result, the effect of the reflected light can be observed more clearly. On the other hand, in the case where the light absorbing layer is not arranged on the back side of the light reflecting layer, the back side of the light reflecting layer will be viewed, and the effect of the reflected light will become unclear, but a design effect that can make the identification medium become a transparent object can be obtained.

[0250] The diffusion layer is a layer that transmits the incident light in a diffused state. The diffusion layer can be arranged at a position closer to the viewing side than the patterned phase difference layer. By arranging the diffusion layer, the viewing angle at which the latent image can be viewed can be expanded. As the diffusion layer, various layered structures known to function as a diffusion layer can be used. Specifically, a layer of a cured product of a resin containing light diffusing particles can be used. Such a layer can be formed on the surface of a transparent film and arranged on the identification medium of the present invention in a composite film state with the transparent film.

[0251] The high phase difference layer is an area with a higher phase difference than the area with phase difference in the patterned phase difference layer. Such a high phase difference layer usually has a very different phase difference according to the wavelength of the incident light. Therefore, in normal observation, it can be viewed as a transparent layer, but when observing the latent image, interference colors are generated and it can be viewed as a colored layer. Therefore, by arranging a high phase difference layer in the display surface of the identification medium, a design effect that can only show the color when observing the latent image can be obtained. As an example of a material constituting the high phase difference layer, a conventional transparent film after stretching can be cited. For example, a transparent tape for bonding, or a transparent tape for bonding after stretching, etc. can be used. The position where the high phase difference layer is set in the identification medium is not particularly limited, and can be set at any position that can present the above-mentioned color.

[0252] The decorative component does not contribute to the function of displaying the identification medium, but it is a component that can contribute to the design effect of the identification medium. As an example of a decorative component, a slice with a metallic luster called a lamé can be cited. Such a slice is arranged in parallel with a slice of a light reflecting layer, or is overlapped on the upper surface of the light reflecting layer. As other examples of decorative components, transparent components such as shell glass covering the display surface of the identification medium, and components such as a housing such as a tray for decorating or protecting the surrounding of the identification medium can be cited.

[0253] The various components constituting the identification medium can be partially or completely embedded in an embedding transparent resin to form an integrated component. In addition, by embedding, for example, the visibility of the edge of the phase difference layer by naked eye observation can be reduced, and as a result, the effect of the identification medium in which the latent image can be observed only in special observation can be further improved.

[0254] Examples of transparent resins for embedding include acrylic, epoxy, polyester, and silicone resins. As the embedding resin, various resins commercially available as curable resin liquids can be used. Specifically, a resin liquid that can form a solid transparent resin by irradiating energy rays such as ultraviolet rays can be used. Among them, when, for example, an acrylic transparent resin is used, a strong and inflexible identification medium can be obtained, while on the other hand, when a silicone transparent resin is used, the obtained identification medium is soft and flexible, and the identification medium can be used as a flexible badge called a silicone badge.

[0255] As other examples of embedding resins, film-like resin materials can be cited. Specifically, a light reflecting layer, a patterned phase difference layer, and any structural elements as required are sandwiched with a pair of film-like resin materials, or a combination of a film-like resin material and other sheet-like materials, and they are bonded together to seal the internal structural elements, thereby forming an identification medium. More specifically, between a backing paper composed of paper, a resin material or a combination thereof and a resin film such as an acrylic film with a small phase difference, structural elements such as a light reflecting layer and a patterned phase difference layer are arranged and sealed, thereby forming a film-like identification medium. Furthermore, by using a backing paper with an adhesive layer on the back as the backing paper, it is possible to easily form an identification medium that can be used as a sticker.

[0256] By embedding the identification medium with a transparent resin, the identification medium can be made into a plate-like product, but it can also be made into any shape other than a plate-like shape by further performing processing such as drilling holes or chamfering.

[0257] The mounting member refers to a member that performs a function when the identification medium is mounted on an article. Part or all of the mounting member may also serve as a decorative member. Examples of mounting members include members such as rings, buckles, hooks, threads, chains, belts, etc. extending from the periphery of the identification medium, and shells such as trays that also serve as decorative members. The mounting member may be directly attached to the light reflecting layer and / or patterned phase difference layer that are necessary structural elements of the identification medium, or may be combined via any member other than these. The combination of these members and the mounting member may be any one of adhesion using an adhesive, adhesion using welding processing, mechanical bonding such as screwing or ligation, etc.

[0258] [Specific example of identification medium]

[0259] refer to Fig.11 and Fig.12 , a more specific example of the identification medium of the present invention is described.

[0260] Fig.11 This is a top view schematically showing a specific example of the identification medium of the present invention. Fig.12 for Fig.11 A longitudinal cross-sectional view of the identification medium shown.

[0261] exist Fig.11 and Fig.12 In the embodiment, the identification medium 50 includes a mounting member 509 and various structural elements provided inside the mounting member 509 for functioning as an identification member. Fig.11 and Fig.12 , the identification medium 50 is shown in a state of being placed horizontally with its display surface facing upward. The mounting member 590 includes a tray 591 and a ring 592 provided at the edge of the tray 591. The ring 592 functions as a member for connecting the identification medium to the article or connecting the identification medium to a belt-shaped member connecting the identification medium and the article when the identification medium is mounted on the article.

[0262] In the tray 591, starting from the bottom, a substrate 511 and a light absorbing layer 521 are laid in sequence. In this example, on the upper part of the light absorbing layer 521, a silver light reflecting layer 501 (S) and a sliced ​​light reflecting layer 501 (P) are arranged in parallel in a partially overlapping state as a light reflecting layer. In this example, these are all reflective circular polarizers. The light reflecting layer 501 (P) can be a silver layer or a layer showing colors such as red, green, and blue.

[0263] Four phase difference layers 502 are further provided on the upper part of the light reflection layers 501 (S) and 501 (P). In this example, the phase difference layer 502 is a star-shaped λ / 4 wave plate occupying a part of the display surface of the identification medium 50, and is provided as a member positioned and bonded to the transparent substrate 512. The slow axes of the four phase difference layers 502 are positioned in different directions from each other.

[0264] A diffusion film 531 having a diffusion layer is disposed on the upper portion of the phase difference layer 502. In this example, the diffusion film 531 is provided so as to cover the entire display surface of the identification medium 50.

[0265] In this example, the light reflecting layer 501 (S), the light reflecting layer 501 (P), the transparent base material 512 , the phase difference layer 502 , and the diffusion film 531 are embedded in a transparent resin, thereby forming transparent resin portions 541 , 542 , and 543 .

[0266] The identification medium 50 is Figure 1 to Figure 6 The identification medium 100 shown in the figure functions on the same principle. Specifically, in addition to the normal observation of the display surface by naked eyes under the environment of non-polarized light incident, it is also possible to observe the display surface through a linear polarizer for observation by incident non-polarized light, observe the display surface through incident linear polarized light, or observe the display surface through incident linear polarized light, or both. When non-polarized light is incident and observed through a linear polarizer for observation, and when linear polarized light is incident and observed, the azimuth angle of the identification medium can be rotated 360° with the vertical direction as the axis, and observation can be performed from the vertical direction.

[0267] When observed with the naked eye, the colors produced by the reflection of the light reflection layers 501 (S) and 501 (P) can be seen on the display surface. The phase difference film 502 is seen as a transparent member, and since it is embedded in a transparent resin, its outline is almost invisible. The difference in brightness between the area occupied by the phase difference film 502 and other areas cannot be seen, and it does not change according to the rotation.

[0268] On the other hand, when non-polarized light is incident and observed through a linear polarizer for observation, and when linear polarized light is incident and observed, the star-shaped shape of the phase difference layer 502 can be observed. The difference in brightness between the area occupied by the phase difference layer 502 and other areas changes according to the rotation. The azimuth angle at which the phase difference layer 502 becomes brightest is irregularly different in each of the multiple phase difference layers 502, so a design effect can be obtained in which multiple star-shaped shapes become brighter one by one through rotation.

[0269] [Specific example of identification medium: Modification example]

[0270] exist Figure 11-12 In the illustrated identification medium 50 , a star-shaped phase difference layer is used as the phase difference layer. However, the shape of the phase difference layer is not limited thereto, and may be any shape such as various graphics or characters.

[0271] exist Figure 11-12 In the identification medium 50 shown, a non-translucent member such as the bottom of the tray 591 and the light absorbing layer 521 is provided on the back side of the light reflecting layer, but it is also possible to configure a transparent identification medium through which the back side of the light reflecting layer can be viewed without providing these. Furthermore, in such a case, another patterned phase difference layer can also be provided at a position closer to the back side than the light reflecting layer. In this case, it is possible to configure an identification medium in which different latent images can be observed when observed from the front side and when observed from the back side.

[0272] [thing]

[0273] The article of the present invention has the above-mentioned identification medium of the present invention.

[0274] Examples of articles include clothing, shoes, hats, jewelry, jewellery, daily necessities and other articles. The article of the present invention can be an article with an identification function by having an identification medium. By having such an identification function, it is possible to identify that the identification medium and the article are not counterfeits but genuine products. In addition, the identification medium can give a design effect to the article. The identification medium can be set on the article as a decoration, component or accessory of an article such as a label, a small ornament, a badge, a sticker, etc.

[0275] In addition to the identification medium of the present invention, the article of the present invention may also have a polarizer observation device. As the polarizer observation device, there can be cited a device having an observation polarizer such as the above-mentioned observation linear polarizer or observation circular polarizer, and arranged on the article in a manner that the identification medium can be observed through such observation polarizer. The polarizer observation device can be made into a shape such as a label and assembled on the article body via a belt or the like. Thus, by having a polarizer observation device in addition to the identification medium, a common article user can easily identify the identification medium.

[0276] Example

[0277] The present invention will be described in detail below with reference to the following examples, but the present invention is not limited to the following examples, and can be arbitrarily modified without departing from the scope of the claims and their equivalents.

[0278] In the following description, "%" and "parts" indicating amounts are based on weight unless otherwise specified. In addition, the operations described below are performed in an atmosphere of normal temperature and pressure unless otherwise specified.

[0279] [Production Example 1: Cholesteric Material (R) (G) (B)]

[0280] A liquid crystal compound (trade name "Paliocolor LC242", manufactured by BASF), a chiral agent (trade name "Paliocolor LC756", manufactured by BASF), a photopolymerization initiator (trade name "Irgacure OXE02", manufactured by BASF), a leveling agent (trade name "Surflon S420", manufactured by AGC Seimi Chemical Co., Ltd.), and a solvent (methyl ethyl ketone) were mixed in the proportions shown in Table 1 below to obtain liquid crystal compositions (R), (G), and (B).

[0281] [Table 1]

[0282] Table 1

[0283] Product Name (B) (G) (R) Paliocolor LC242 17.90 18.10 18.31 Paliocolor LC756 1.48 1.28 1.07 lrgacure OXE02 0.60 0.60 0.60 Surflon S420 0.02 0.02 0.02 MEK 80.00 80.00 80.00

[0284] All proportions are by weight

[0285] The surface of the raw material substrate (PET film, manufactured by Toyobo Co., Ltd., trade name "A4100") is subjected to a friction treatment. Liquid crystal compositions (R), (G) and (B) are respectively applied to the surface using a rod coater to form a layer of the liquid crystal composition. The thickness of the layer of the liquid crystal composition is adjusted so that the thickness of the final cholesteric material layer is 3.5 μm. The layer of the liquid crystal composition is dried and oriented by heating it at 100°C in an oven for 2 minutes. Next, the dried layer of the liquid crystal composition is irradiated with ultraviolet rays in a nitrogen environment (oxygen concentration below 400 ppm). During the irradiation, a high-pressure mercury lamp is used with an illumination of 280 mW / cm at 365 nm (i line). 2 、Exposure 2000mJ / cm 2 The irradiation conditions were adjusted in a manner as follows. As a result, polymerization with a residual monomer ratio of about 2 wt % was achieved, and the layer of the liquid crystal composition was cured to form a cholesteric material layer. Thus, a raw material sheet including a raw material substrate and a cholesteric material layer was obtained.

[0286] [Production Example 2: Cholesteric Material (S)]

[0287] 14.63 parts by weight of a liquid crystal compound (the compound represented by the above formula (B3)), 3.66 parts by weight of an alignment aid (the compound represented by the above formula (A2)), 1.09 parts by weight of a chiral agent (trade name "Paliocolor LC756", manufactured by BASF), 0.02 parts by weight of a leveling agent (trade name "Surflon S420", manufactured by AGC Seimi Chemical Co., Ltd.), 0.60 parts by weight of a photopolymerization initiator (trade name "Irgacure OXE02", manufactured by BASF), and 80.00 parts by weight of a solvent (methyl ethyl ketone) are mixed to obtain a liquid crystal composition (S).

[0288] The surface of the raw material substrate (PET film, manufactured by Toyobo Co., Ltd., trade name "A4100") was subjected to a rubbing treatment. The liquid crystal composition (S) was applied to the surface using a bar coater to form a layer of the liquid crystal composition. The thickness of the layer of the liquid crystal composition was adjusted so that the thickness of the cholesteric material layer finally obtained was about 5 μm. The layer of the liquid crystal composition was dried and oriented by heating it at 140° C. in an oven for 2 minutes.

[0289] Next, broadband treatment is performed. The broadband treatment is performed by irradiating the dried liquid crystal composition layer with weak ultraviolet light in an atmospheric environment and then heating it. During the ultraviolet irradiation, a high-pressure mercury lamp is used with an illumination of 25 mW / cm at 365 nm (i line). 2The irradiation was performed for 0.3 seconds and then heated at 90°C for 1 minute.

[0290] Next, the dried liquid crystal composition layer was irradiated with ultraviolet light for curing in a nitrogen atmosphere (oxygen concentration 400 ppm or less). During the irradiation, a high pressure mercury lamp was used with an illuminance of 280 mW / cm at 365 nm (i line). 2 、Exposure 2000mJ / cm 2 The irradiation conditions are adjusted in a manner of . As a result, the layer of the liquid crystal composition is cured to form a cholesteric material layer (S). Thus, a raw material sheet including a raw material substrate and a cholesteric material layer (S) is obtained.

[0291] [Manufacturing Example 3: Small membrane of cholesteric material]

[0292] The raw material sheets containing the cholesteric material layer obtained in Manufacturing Examples 1 and 2 were bent and air was blown to peel off the cholesteric material layer to obtain peeled sheets. The peeled sheets were crushed with a blender to form slices with a long diameter of about 2 mm as small membrane sheets. Thus, small membrane sheets (R), (G), (B) and (S) of cholesteric material were obtained.

[0293] [Manufacturing Example 4: Cholesteric Material Layer]

[0294] The cholesteric material layer side surface of the raw material sheet containing the cholesteric material layer obtained in Production Examples 1 and 2 was bonded to a substrate ("Zeonor ZF-14", manufactured by Zeon Co., Ltd., thickness 23 μm) different from the raw material substrate via an ultraviolet curing adhesive (ARONIX UCX-800 manufactured by Toagosei Co., Ltd.), and the raw material substrate was peeled off to transfer the cholesteric material layer. Thus, cholesteric material layer sheets (R), (G), (B) and (S) were obtained, which contained a substrate and a cholesteric material layer provided on the surface thereof via an adhesive layer.

[0295] [Production Example 5: Thin sheet of cholesteric material]

[0296] The cholesteric material layer obtained in Production Example 4 was cut into random-shaped slices with a cutter to prepare thin sheets. Thus, thin sheets (R), (G), (B) and (S) of the cholesteric material were obtained.

[0297] [Production Example 6: Pigment of Cholesteric Material (S)]

[0298] The raw material sheet containing the cholesteric material layer obtained in Preparation Example 2 was bent and air was blown to peel off the cholesteric material layer to obtain a peeling sheet. The peeling sheet was crushed with a shredder and passed through a 51 μm sieve, and the particles passing through the sieve were recovered to obtain a cholesteric material pigment (S). The particle size distribution of the pigment was measured by a laser diffraction / scattering method using a particle size distribution measuring device (product name "LA-960", manufactured by Horiba, Ltd.), and the average particle size of the pigment particles was calculated, and the result was 30 μm.

[0299] [Manufacturing Example 7: Phase difference layer: λ / 4 stretched resin film]

[0300] A stretched resin film having a phase difference (trade name "Zeonor ZD-12", manufactured by Zeon Co., Ltd., thickness 55 μm, Re (450) 141 nm, Re (550) 140 nm, Re (650) 140 nm) was prepared. The resin film was punched out with a craft punch to obtain a star-shaped λ / 4 stretched resin film used as a phase difference layer.

[0301] [Manufacturing Example 8: Phase difference layer: λ / 4 liquid crystal cured film]

[0302] Using the method described in Comparative Example 5 of International Publication No. 2019 / 116995, a multilayer film A having a supporting substrate and a layer A is obtained, wherein the layer A is arranged on the supporting substrate and is composed of a cured product of a liquid crystal composition.

[0303] The obtained multilayer film A was punched out with a punch to produce a film sheet having a star shape. The Re of the layer A portion of the obtained multilayer film sheet was Re (450) 120 nm, Re (550) 145 nm, and Re (650) 151 nm.

[0304] [Manufacturing Example 9: Patterned Phase Difference Layer: λ / 4-Isotropic Composite Layer]

[0305] 14.78 parts by weight of a liquid crystal compound (trade name "Paliocolor LC242", manufactured by BASF), 3.70 parts by weight of a multifunctional acrylate (trade name "A-TMPT", manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 2.13 parts by weight of a leveling agent (trade name "Surflon S420", manufactured by AGC Seimi Chemical Co., Ltd.), 0.39 parts by weight of a polymerization initiator Irgacure 184 (manufactured by BASF), 0.19 parts by weight of a polymerization initiator Irgacure 907 (manufactured by BASF), and 77.89 parts by weight of a solvent (methyl ethyl ketone) were mixed to obtain a liquid crystal composition.

[0306] The surface of the substrate film (trade name "Zeonor ZF16", film thickness 55 μm, optically isotropic film) was subjected to corona treatment and friction treatment. The liquid crystal composition was applied to the surface with a rod coater to form a layer of the liquid crystal composition. The thickness of the layer of the liquid crystal composition was adjusted so that the thickness of the final patterned phase difference layer was about 1.3 μm. The layer of the liquid crystal composition was dried and oriented by heating it at 100° C. in an oven for 2 minutes to obtain a multilayer 2 having a substrate film and a layer of a dried liquid crystal composition disposed thereon.

[0307] Two masks, negative and positive, are prepared. They both have a pattern with a plurality of stars arranged in the same outline. The negative mask blocks light from the inside of the stars and transmits light from the outside of the stars, while the positive mask transmits light from the inside of the stars and blocks light from the outside of the stars.

[0308] Next, the layer of the liquid crystal composition was irradiated with weak ultraviolet light (10 mJ / cm 2 The irradiation was performed through a positive mask. Then, the multilayer 2 was placed on a hot plate at 110° C. and heated for 1 minute to make the unexposed portion into an isotropic phase.

[0309] Next, in a nitrogen atmosphere, the entire surface of the liquid crystal composition layer was irradiated with ultraviolet light (500 mJ / cm 2 ), and the entire surface of the layer of the liquid crystal composition is cured. Thus, a multilayered product 3 having a substrate film and a λ / 4-isotropic composite layer disposed thereon is obtained.

[0310] Re was measured for the inner and outer regions of the star-shaped pattern of the obtained multilayer 3. The results showed that the inner region had Re (450) of 160 nm, Re (550) of 146 nm, and Re (650) of 140 nm, while the outer region had 0 nm at any wavelength. Therefore, it was confirmed that the inner region functioned as a λ / 4 wave plate and the outer region functioned as an isotropic layer.

[0311] [Manufacturing Example 10: Patterned Phase Difference Layer: λ / 4-λ / 2 Composite Layer]

[0312] A multilayer product 4 having a base film and a λ / 4-isotropic composite layer provided thereon was obtained by the same operation as in Production Example 9 except that a negative mask was used as the mask instead of the positive mask.

[0313] The surface of the multilayer 4 on the λ / 4-isotropic composite layer side was bonded to the same resin film used in Production Example 7 via an adhesive ("CS9621T" manufactured by Nitto Denko Corporation). During bonding, the slow axis of the λ / 4-isotropic composite layer and the slow axis of the resin film were aligned so that they were in the same direction. Thus, a multilayer 5 having a base film, a λ / 4-isotropic composite layer disposed thereon, and a resin film disposed thereon was obtained.

[0314] Re was measured for the inner and outer regions of the star-shaped pattern of the obtained multilayer 5. As a result, the inner region had Re (450) of 141 nm, Re (550) of 140 nm, and Re (650) of 140 nm, and the outer region had Re (450) of 201 nm, Re (550) of 286 nm, and Re (650) of 280 nm. Therefore, it was confirmed that the inner region functioned as a λ / 4 wave plate, and the outer region functioned as a λ / 2 wave plate.

[0315] [Manufacturing Example 11: Phase difference layer: λ / 2 stretched resin film]

[0316] Two sheets of the same resin film as the resin film used in Manufacturing Example 7 were bonded together via an adhesive ("CS9621T" manufactured by Nitto Denko Corporation). When bonding, the orientations of the two sheets of resin film were unified so that the slow axes thereof were in the same direction. The multilayered resin film was punched out with a pattern punch to obtain a star-shaped λ / 2 stretched resin film used as a phase difference layer.

[0317] [Production Example 12: Isotropic resin film]

[0318] An optically isotropic resin film (PET film, manufactured by Toyobo Co., Ltd., trade name "A4100") was punched out with a punch to obtain an isotropic resin film having a star shape used in the comparative example.

[0319] [Example 1]

[0320] (1-1. Light reflecting layer)

[0321] The light absorbing layer (black PET film; the same applies hereinafter) was placed horizontally, and the cholesteric material layer sheet (G) obtained in Production Example 4 was bonded to the upper surface thereof via an adhesive as a light reflecting layer.

[0322] (1-2. Phase difference layer)

[0323] Furthermore, multiple sheets of the star-shaped λ / 4 stretched resin film obtained in Production Example 7 were attached as a phase difference layer via an adhesive so as to cover a part of the surface area of ​​the light reflection layer. The multiple sheets of λ / 4 stretched resin film were arranged in a state where their slow axis directions were not uniform and were irregularly oriented in various directions. Thus, an identification medium having a light absorption layer, a light reflection layer, and a phase difference layer was obtained.

[0324] (1-3. Observation)

[0325] The identification medium is kept horizontally placed, and the azimuth angle is rotated 360 degrees, and the observer observes from the vertical direction. The observation is performed both with the naked eye and through the linear polarizer of polarized sunglasses. The observation is performed in a bright room with fluorescent lamps as the light source.

[0326] When observed with the naked eye, green color generated by the reflection of the cholesteric material layer (G) can be seen in the display surface. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts in the display surface cannot be seen, and it does not change due to rotation.

[0327] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer can be seen. The difference in brightness between the star-shaped portion and the rest of the display surface changes according to the rotation. The azimuth at which the phase difference layer becomes brightest is different for each of the multiple phase difference layers, so a design effect can be obtained in which multiple stars are brightened one by one in a random order by rotation.

[0328] [Example 2]

[0329] An identification medium was obtained and observed by the same operation as in Example 1 except that the cholesteric material layer sheet (S) was used as the light reflecting layer instead of the cholesteric material layer sheet (G).

[0330] When observed with the naked eye, silver color produced by the reflection of the cholesteric material layer (S) can be seen in the display surface. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts in the display surface cannot be seen, and it does not change with rotation.

[0331] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer can be seen. The difference in brightness between the star-shaped portion and the other portions of the display surface changes according to the rotation. The azimuth at which the phase difference layer becomes brightest is different in each of the multiple phase difference layers, so a design effect can be obtained in which multiple stars are brightened one by one in a random order by rotation. Since it is a reflection of silver light, the shape of the phase difference layer and the change in its brightness can be seen more clearly than in Example 1.

[0332] [Example 3]

[0333] (3-1. Light reflecting layer)

[0334] An adhesive is applied to the upper surface of a horizontally placed light absorbing layer, and the small film pieces (R), (G), (B) and (S) obtained in Manufacturing Example 3 are mixed, arranged and bonded thereon to form a light reflecting layer as a layer in which the small film pieces (R), (G), (B) and (S) are mixed.

[0335] (3-2. Phase difference layer)

[0336] Furthermore, multiple sheets of the star-shaped λ / 4 stretched resin film obtained in Production Example 7 were attached as a phase difference layer via an adhesive so as to cover a part of the surface area of ​​the light reflection layer. The multiple sheets of λ / 4 stretched resin film were arranged in a state where their slow axis directions were not uniform and were irregularly oriented in various directions. Thus, an identification medium having a light absorption layer, a light reflection layer, and a phase difference layer was obtained.

[0337] (3-3. Observation)

[0338] The identification medium obtained in (3-2) was observed by the same operation as in (1-3) of Example 1.

[0339] When observed with the naked eye, a mixed state of red, green, blue and silver areas is seen on the display surface due to the reflection of the small films (R), (G), (B) and (S). The phase difference layer is viewed as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts of the display surface cannot be seen, and it does not change with rotation.

[0340] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. The difference in brightness between the star-shaped portion and the other portions of the display surface changes according to the rotation. The azimuth at which the phase difference layer becomes brightest is different in each of the multiple phase difference layers, so a design effect can be obtained in which multiple stars are brightened one by one in a random order by rotation. Since it is a reflection of red, green, blue and silver light, the shape of the phase difference layer and the change in its brightness can be seen more clearly than in Example 1.

[0341] In each star-shaped area, tiny areas of red, green, blue and silver based on small diaphragms (R), (G), (B) and (S) are mixed, and although these colors are different, the way the brightness changes in a star shape is the same. Therefore, even if small diaphragms of various colors are mixed, the same recognition function of the present application can be easily obtained, so that both the recognition function and a high degree of design freedom can be taken into account.

[0342] [Example 4]

[0343] (4-1. Light reflecting layer)

[0344] An adhesive is applied to the upper surface of a horizontally placed light absorbing layer, and the thin sheets (R), (G), (B) and (S) obtained in Manufacturing Example 5 are mixed, arranged and bonded thereon to form a light reflecting layer as a layer in which the thin sheets (R), (G), (B) and (S) are mixed.

[0345] (4-2. Phase difference layer)

[0346] Furthermore, multiple sheets of the star-shaped λ / 4 stretched resin film obtained in Production Example 7 were attached as a phase difference layer via an adhesive so as to cover a part of the surface area of ​​the light reflection layer. The multiple sheets of λ / 4 stretched resin film were arranged in a state where their slow axis directions were not uniform and were irregularly oriented in various directions. Thus, an identification medium having a light absorption layer, a light reflection layer, and a phase difference layer was obtained.

[0347] (4-3. Observation)

[0348] The identification medium obtained in (4-2) was observed by the same operation as in (1-3) of Example 1.

[0349] When observed with the naked eye, a mixed state of red, green, blue and silver regions generated by reflections of the sheets (R), (G), (B) and (S) is seen on the display surface. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped portion and other portions on the display surface cannot be seen, and it does not change with rotation.

[0350] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. The difference in brightness between the star-shaped portion and the other portions of the display surface changes according to the rotation. The azimuth at which the phase difference layer becomes brightest is different in each of the multiple phase difference layers, so a design effect can be obtained in which multiple stars are brightened one by one in a random order by rotation. Since it is a reflection of red, green, blue and silver light, the shape of the phase difference layer and the change in its brightness can be seen more clearly than in Example 1.

[0351] In each star-shaped region, red, green, blue, and silver regions based on the flakes (R), (G), (B), and (S) are mixed, and although these colors are different, the way the brightness changes within a star shape is the same. Therefore, even if flakes of various colors are mixed, the same recognition function of the present application can be easily obtained, so that both the recognition function and a high degree of design freedom can be taken into account.

[0352] [Example 5]

[0353] (5-1. Light reflecting layer)

[0354] A coating material was prepared using the pigment (S) obtained in Production Example 6. A pattern was drawn with the coating material on the upper surface of the horizontally placed light absorbing layer, and the pattern was dried to form a light reflecting layer as a layer of the pigment (S).

[0355] (5-2. Phase difference layer)

[0356] Furthermore, multiple sheets of the star-shaped λ / 4 stretched resin film obtained in Production Example 7 were attached as a phase difference layer via an adhesive so as to cover a part of the surface area of ​​the light reflection layer. The multiple sheets of λ / 4 stretched resin film were arranged in a state where their slow axis directions were not uniform and were irregularly oriented in various directions. Thus, an identification medium having a light absorption layer, a light reflection layer, and a phase difference layer was obtained.

[0357] (5-3. Observation)

[0358] The identification medium obtained in (5-2) was observed by the same operation as in Example 1 (1-3).

[0359] When observed with the naked eye, silver color due to the reflection of the pigment (S) and black color due to the light absorbing layer in the portion without the pattern formed by the pigment (S) are seen on the display surface. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped portion and other portions on the display surface cannot be seen, and it does not change due to rotation.

[0360] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer is seen in the portion where the light reflection layer and the phase difference layer overlap. The difference in brightness between the star-shaped portion and the rest of the display surface changes with rotation. The azimuth at which the phase difference layer becomes brightest is different for each of the multiple phase difference layers, so a design effect can be obtained in which multiple stars are brightened one by one in a random order by rotation.

[0361] Furthermore, since a pattern can be freely drawn using the pigment (S), a high degree of freedom in design can be obtained.

[0362] [Example 6]

[0363] The cholesteric material layer sheet (G) obtained in Manufacturing Example 4 is placed horizontally on a table as a light reflecting layer. Furthermore, multiple sheets of the star-shaped λ / 4 stretched resin film obtained in Manufacturing Example 7 are attached via an adhesive so as to cover a part of the surface area of ​​the light reflecting layer as a phase difference layer. The multiple sheets of λ / 4 stretched resin film are arranged in a state where their slow axis directions are not uniform and are irregularly oriented in various directions. Thus, an identification medium having a light reflecting layer and a phase difference layer is obtained.

[0364] The obtained identification medium is observed by the same operation as (1-3) of Example 1. When observed with the naked eye, green color produced by the reflection of the cholesteric material layer (G) is seen on the display surface. However, since the cholesteric material layer (G) is translucent, the green color of the cholesteric material layer (G) is seen in a state mixed with the color of the surface of the table. The phase difference layer is viewed as a transparent component, and the star shape is almost invisible. The difference in brightness between the star-shaped portion and other portions on the display surface cannot be seen, and it does not change according to the rotation.

[0365] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. The difference in brightness between the star-shaped portion and other portions of the display surface changes according to the rotation. The azimuth at which the phase difference layer becomes brightest is different in each of the multiple phase difference layers, so a design effect can be obtained in which multiple stars are brightened one by one in a random order by rotation. Since there is no light absorbing layer, the background is visible, so the shape of the phase difference layer and the change in its brightness are somewhat unclear compared to Example 1, but a design effect that can make the identification medium transparent can be obtained.

[0366] [Example 7]

[0367] In (4-2), the identification medium was obtained and observed by the same operation as in Example 4 except that the layer A contained in the film obtained in the multi-layer film was provided instead of the λ / 4 stretched resin film obtained in the multi-layer film 7. Specifically, the operation of providing the layer A was performed by bonding the surface of the layer A side of the film of the multi-layer film to the light reflecting layer via an adhesive and further peeling off the supporting substrate. The multi-layer layer A was provided in a state where the slow axis directions were not uniform and were irregularly oriented in various directions.

[0368] When observed with the naked eye, a mixed state of red, green, blue and silver regions generated by reflections of the sheets (R), (G), (B) and (S) is seen on the display surface. The difference between the inner and outer sides of the star shape of the multilayer 1 is almost invisible. The difference in brightness between the star-shaped part and the other parts on the display surface is not visible, and it does not change with rotation.

[0369] On the other hand, when viewed through polarized sunglasses, the inner side of the star shape functions as a phase difference layer, and the star shape of the phase difference can be seen. The difference in brightness between the star-shaped portion and the other portions of the display surface changes according to the rotation, and the same effect as in Example 4 can be obtained. In addition, the black color in which the phase difference layer becomes the darkest state is darker than that in Example 4, and is a vivid black with few mixed colors.

[0370] [Example 8]

[0371] In (4-2), an identification medium was obtained and observed by the same operation as in Example 4 except that the multilayer 3 obtained in Production Example 9 was provided instead of the plurality of λ / 4 stretched resin films obtained in Production Example 7.

[0372] When observed with the naked eye, a mixed state of red, green, blue and silver regions generated by reflections of the sheets (R), (G), (B) and (S) is seen on the display surface. The difference between the inner and outer sides of the star shape of the multilayer 3 is almost invisible. The difference in brightness between the star-shaped part and the other parts on the display surface is not visible, and it does not change with rotation.

[0373] On the other hand, when viewed through polarized sunglasses, the inside of the star functions as a phase difference layer, and the star shape of the phase difference layer can be seen. The difference in brightness between the star-shaped portion and the rest of the display surface changes according to the rotation, and the same effect as in Example 4 is obtained. In addition, the black color in which the phase difference layer becomes the darkest state is darker than that in Example 4, and is a bright black with few mixed colors. However, since the slow axis of the phase difference layer is in the same direction in all the stars, it is not possible to obtain a design effect in which multiple stars become brighter one by one, and the brightness of all the stars changes in the same way according to the rotation.

[0374] [Example 9]

[0375] In (4-2), an identification medium was obtained and observed by the same operation as in Example 4 except that the multilayered product 5 obtained in Production Example 10 was provided instead of the plurality of λ / 4 stretched resin films obtained in Production Example 7.

[0376] When observed with the naked eye, a mixed state of red, green, blue and silver regions generated by reflections of the sheets (R), (G), (B) and (S) is seen on the display surface. The difference between the inner and outer sides of the star shape of the multilayer 5 is almost invisible. The difference in brightness between the star-shaped part and the other parts on the display surface is not visible, and it does not change with rotation.

[0377] On the other hand, when observed through polarized sunglasses, the inside of the star functions as a phase difference layer, and the star shape of the phase difference layer can be seen. The difference in brightness between the star-shaped portion and other portions of the display surface changes according to the rotation, and the same effect as in Example 4 is obtained. In addition, the black color in the darkest state of the phase difference layer is darker than that in Example 4, and is a bright black with few mixed colors. However, since the slow axis of the phase difference layer is in the same direction in all stars, it is not possible to obtain a design effect in which multiple stars become brighter one by one, and the brightness of all stars changes in the same way according to the rotation. On the outside of the star, the changes due to the rotation are almost invisible, but slight color changes can be observed compared to Example 4.

[0378] [Example 10]

[0379] The light absorbing layer was placed horizontally, and a linear polarizer was bonded to the upper surface thereof via an adhesive as a light reflecting layer. As the linear polarizer, a film having a plurality of thin films laminated thereon (trade name "DBEF", manufactured by 3M Company) was used.

[0380] Furthermore, multiple sheets of the star-shaped λ / 2 stretched resin film obtained in Manufacturing Example 11 were bonded as phase difference layers via an adhesive in a manner that covered a portion of the surface area of ​​the light reflection layer. The slow axis directions of the multiple sheets of λ / 2 stretched resin films were unified in a direction that formed an angle of 45° with the transmission axis of the light reflection layer. Thus, an identification medium having a light absorption layer, a light reflection layer, and a phase difference layer was obtained. The obtained identification medium was observed by the same operation as (1-3) of Example 1.

[0381] When observed with the naked eye, silver color is seen on the display surface due to reflection from the linear polarizer. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts on the display surface cannot be seen, and it does not change with rotation.

[0382] On the other hand, when observing through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. The difference in brightness between the star-shaped part and the other parts of the display surface changes according to the rotation. Since it is a reflection of silver light, the shape of the phase difference layer and the change in its brightness can be clearly seen as in Example 2. However, since the slow axis of the phase difference layer is in the same direction in all the stars, it is impossible to obtain a design effect in which multiple stars become brighter one by one, and the brightness of all the stars changes in the same way according to the rotation.

[0383] [Example 11]

[0384] Instead of the film of laminated thin films, a wire grid polarizer (trade name "WGPF-30C", manufactured by Sigma Koki Co., Ltd.) was used as the linear polarizer for the light reflecting layer. Except for this change, the same operation as in Example 10 was performed to obtain an identification medium, and the identification medium was observed.

[0385] When observed with the naked eye, silver color is seen on the display surface due to reflection from the linear polarizer. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts on the display surface cannot be seen, and it does not change with rotation.

[0386] On the other hand, when observing through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. The difference in brightness between the star-shaped part and the other parts of the display surface changes according to the rotation. Since it is a reflection of silver light, the shape of the phase difference layer and the change in its brightness can be clearly seen as in Example 2. However, since the slow axis of the phase difference layer is in the same direction in all the stars, it is impossible to obtain a design effect in which multiple stars become brighter one by one, and the brightness of all the stars changes in the same way according to the rotation.

[0387] [Example 12]

[0388] An adhesive is applied to the upper surface of the horizontally placed light absorbing layer, and the flakes (R), (G), (B) and (S) obtained in Production Example 5 are mixed, arranged and bonded thereon to form a light reflecting layer as a layer in which the flakes (R), (G), (B) and (S) are mixed. Furthermore, a plurality of star-shaped λ / 4 stretched resin films obtained in Production Example 7 are bonded as phase difference layers via an adhesive so as to cover a part of the surface of the light reflecting layer to obtain a laminate. The plurality of λ / 4 stretched resin films are arranged in a state where the slow axis directions are not uniform and are randomly oriented in various directions.

[0389] Then, an acrylic resin liquid (commercially available ultraviolet curable acrylic resin liquid, the same below) was injected from the top of the laminate, and ultraviolet light was irradiated for 2 minutes using an ultraviolet light emitting LED to cure the acrylic resin liquid. Thus, an identification medium having a light absorption layer, a light reflection layer, and a phase difference layer in a state of being embedded in an acrylic resin was obtained. The obtained identification medium was observed by the same operation as (1-3) of Example 1.

[0390] When observed with the naked eye, a mixed state of red, green, blue and silver regions produced by reflections of the sheets (R), (G), (B) and (S) is seen on the display surface. Since the phase difference layer is embedded in acrylic resin, the edge portion is not obvious, and the degree of star shape visible is lower than that in Example 4. The difference in brightness between the star-shaped portion and other portions on the display surface cannot be seen, and it does not change with rotation.

[0391] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. The difference in brightness between the star-shaped portion and the other portions of the display surface changes with rotation, and the same effect as in Example 4 is obtained.

[0392] [Example 13]

[0393] An adhesive is applied to the upper surface of the horizontally placed light absorbing layer, and the flakes (R), (G), (B) and (S) obtained in Production Example 5 and small pieces of glossy metal are mixed, arranged and bonded thereon to form a light reflecting layer as a mixed layer. Furthermore, a plurality of star-shaped λ / 4 stretched resin films obtained in Production Example 7 are bonded as a phase difference layer via an adhesive so as to cover a part of the surface area of ​​the light reflecting layer. The plurality of λ / 4 stretched resin films are arranged in a state where the slow axis directions are not uniform and are randomly oriented in various directions.

[0394] Then, an acrylic resin liquid was injected from above, and ultraviolet light was irradiated for 2 minutes using an ultraviolet light emitting LED to cure the acrylic resin liquid. Thus, an identification medium having a light absorbing layer, a metal flake, a light reflecting layer, and a phase difference layer embedded in an acrylic resin was obtained. The obtained identification medium was observed by the same operation as (1-3) of Example 1.

[0395] When observed with the naked eye, a mixed state of red, green, blue and silver regions produced by reflection of the flakes (R), (G), (B) and (S) and the metal flakes is seen on the display surface. Since the phase difference layer is embedded in the acrylic resin, the edge portion is not obvious, and the degree of star shape visible is lower than that of Example 4. The difference in brightness between the star-shaped portion and other portions on the display surface cannot be seen, and it does not change according to the rotation.

[0396] On the other hand, when viewed through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. In the area where the phase difference layer overlaps with the sheets (R), (G), (B), and (S), the difference in brightness between the star-shaped portion and the other portions of the display surface changes according to the rotation, and the same effect as in Example 4 is obtained. In the area where the sheets (R), (G), (B), and (S) do not exist but the metal flakes exist, the brightness of the area of ​​the phase difference layer does not change, so a design effect in which the brightness changes only in a partial area can be obtained.

[0397] [Example 14]

[0398] An adhesive is applied to the upper surface of a horizontally placed light absorbing layer, and the thin sheets (R), (G), (B) and (S) obtained in Manufacturing Example 5 are mixed, arranged and bonded thereon to form a light reflecting layer which is a layer in which the thin sheets (R), (G), (B) and (S) are mixed.

[0399] Grasp the two ends of the transparent tape in the longitudinal direction with fingers and stretch it to obtain a tape with uneven phase difference. Attach it to a part of the upper surface of the light reflecting layer. Then, a plurality of star-shaped λ / 4 stretched resin films obtained in Manufacturing Example 7 are attached as phase difference layers via an adhesive in a manner that covers a part of the surface of the light reflecting layer and the transparent tape. The plurality of λ / 4 stretched resin films are arranged in a state where their slow axis directions are not uniform and are irregularly oriented in various directions.

[0400] Then, an acrylic resin liquid was injected from above, and ultraviolet light was irradiated for 2 minutes using an ultraviolet light emitting LED to cure the acrylic resin liquid. Thus, an identification medium having a light absorbing layer, a transparent tape, a light reflecting layer, and a phase difference layer in a state of being embedded in an acrylic resin was obtained. The obtained identification medium was observed by the same operation as (1-3) of Example 1.

[0401] When observed with the naked eye, in the display surface, the red, green, blue and silver areas produced by the reflection of the sheets (R), (G), (B) and (S) are seen mixed. Since the phase difference layer is embedded in the acrylic resin, the edge portion is not obvious, and the degree of star shape visible is lower than that in Example 4. The difference in brightness between the star-shaped part and the other parts in the display surface cannot be seen, and it does not change according to the rotation. The transparent tape is also the same as the phase difference layer, and the edge portion is not obvious and can hardly be seen.

[0402] On the other hand, when observing through polarized sunglasses, the star-shaped shape of the phase difference layer is seen. In the area where the phase difference layer overlaps with the sheets (R), (G), (B) and (S), the difference in brightness between the star-shaped portion and the other portions of the display surface changes according to the rotation, and the same effect as in Example 4 is obtained. In the area where the phase difference layer overlaps with the transparent tape, the brightness of the area of ​​the phase difference layer does not change, and the uneven changes in brightness and color caused by the uneven phase difference of the transparent tape can be seen.

[0403] [Example 15]

[0404] Inject acrylic resin liquid into a silicone mold, irradiate ultraviolet light to cure it, and form an acrylic resin layer. Further inject acrylic resin liquid on it to form an acrylic resin liquid layer. In the acrylic resin liquid layer, the back phase difference layer, the light reflection layer, and the front phase difference layer are buried in sequence. Use multiple pieces of star-shaped λ / 4 stretched resin film obtained in Manufacturing Example 7 as the back phase difference layer and the front phase difference layer. Mix the thin sheets (R), (G), (B) and (S) obtained in Manufacturing Example 5 and use them as the light reflection layer. Multiple pieces of λ / 4 stretched resin films as the back phase difference layer and the front phase difference layer are placed in a state where their slow axis directions are not uniform and irregularly facing various directions. Further inject acrylic resin liquid on it to make the surface flat, irradiate ultraviolet light to cure the acrylic resin liquid. Thus, an identification medium having a back phase difference layer, a substrate film, a light reflection layer, and a front phase difference layer in a state embedded in acrylic resin is formed. The obtained identification medium was observed by the same operation as (1-3) of Example 1. However, observation was performed both from the front side and from the back side.

[0405] When observed with the naked eye, in the display surface, the red, green, blue and silver regions generated by the reflection of the sheets (R), (G), (B) and (S) are seen mixed. Since the phase difference layer is embedded in the acrylic resin, the edge portion is not obvious, and the degree to which the star shape is seen is lower than that in Example 4. The difference in brightness between the star-shaped portion and the other portions in the display surface cannot be seen, and it does not change according to the rotation. The observation result is the same when observing from the front side and from the back side.

[0406] On the other hand, when observing through polarized sunglasses, the star-shaped shape of the phase difference layer on the front side is seen when observing from the front side, and the star-shaped shape of the phase difference layer on the back side is seen when observing from the back side. Since there is no light absorption layer, the background is visible, so the shape of the phase difference layer and the change in brightness are somewhat unclear compared to Example 1, but the design effect of making the identification medium transparent and the design effect of being able to see the brightness change caused by different phase difference layers by observing from the front side and from the back side can be obtained.

[0407] [Example 16]

[0408] The identification medium was obtained and observed by the same operation as in Example 12 except that a silicone resin liquid was used for embedding instead of light-curing an acrylic resin liquid. As the silicone resin, a resin liquid containing a curing agent and curing over time by standing at room temperature was prepared. This was injected from above a laminate including a light reflecting layer and a phase difference layer, and allowed to stand, thereby embedding.

[0409] When the observation was performed, the same observation results as those in Example 12 were obtained. In addition, the cured silicone resin is more flexible than the acrylic resin. Therefore, the obtained identification medium has the characteristics of being highly flexible and being able to be attached to items requiring flexibility such as clothing as badges.

[0410] [Example 17]

[0411] (17-1. Diffusion film)

[0412] An adhesive composition was prepared, which consisted of 40 parts by weight of an ethylene-vinyl acetate copolymer emulsion (40% by weight of non-volatile components, 40% by weight of vinyl acetate content), 35 parts by weight of a petroleum resin emulsion (40% by weight of non-volatile components, resin softening point 85°C), and 10 parts by weight of a paraffin emulsion (40% by weight of non-volatile components, resin softening point 64°C), and had a shear storage modulus of 10 MPa at 23°C. Fine particles (shape: spherical, material: polystyrene, refractive index: 1.59) with a diameter of 4 μm were added to the adhesive composition to obtain a diffusion adhesive composition. The amount of fine particles added was adjusted so that the haze of the obtained diffusion film was 40%.

[0413] The surfaces of two transparent films (non-stretched ZEONOR film, product name "ZF14", manufactured by Japan Zeon Co., Ltd., thickness 40 μm, front phase difference 3 nm or less) were subjected to corona treatment. A diffusion adhesive composition was applied to one film, and another film was stacked on top of it to form a deposit, which was then laminated by applying pressure to the deposit using a laminator. Thus, a diffusion film having two transparent films and a diffusion layer between them was obtained.

[0414] (17-2. Identification medium)

[0415] The diffusion film obtained in (17-1) was further placed on the identification medium obtained in (4-2) of Example 4 so as to cover the entire display surface. Thus, an identification medium having a light absorbing layer, a light reflecting layer, a phase difference layer, and a diffusion film was obtained.

[0416] The obtained identification medium was observed by the same operation as (1-3) of Example 1. As a result, the same effect as that of Example 4 was obtained.

[0417] Furthermore, observation is performed from an oblique direction. That is, while maintaining the identification medium in a horizontal position, the azimuth angle is rotated 360°, and observation is performed by making various changes in the range of the polar angle from 0° to 60° in the vertical direction. As observation, both naked eye observation and observation through a linear polarizer of polarized sunglasses are performed. The observation is performed in a bright room with a fluorescent lamp as the light source. The same observation is also performed on the identification medium obtained in Example 4, and the results are compared.

[0418] When observed with the naked eye, the same results as observed from a vertical direction are obtained.

[0419] On the other hand, when observing through polarized sunglasses, the larger the polar angle, the more blurred the star-shaped shape of the phase difference layer and the change in the difference in brightness between the star-shaped portion and the other portions. However, when comparing the observation results of Example 17 with the observation results of Example 4, in the observation results of Example 17, the star-shaped shape of the phase difference layer and the change in the difference in brightness between the star-shaped portion and the other portions are relatively obvious even at a large polar angle.

[0420] [Comparative Example 1]

[0421] An identification medium was obtained and observed by the same operation as in Examples 1 and 2 except that an aluminum foil was used as the light reflecting layer instead of the cholesteric material layer sheet.

[0422] When observed with the naked eye, silver color is seen on the display surface due to the reflection of the aluminum foil. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts on the display surface cannot be seen, and it does not change with rotation.

[0423] Even when viewed through polarized sunglasses, the phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts of the display surface cannot be seen, and it does not change with rotation. Therefore, at any azimuth angle, the star shape cannot be seen more clearly than with the naked eye.

[0424] [Comparative Example 2]

[0425] An identification medium was obtained and observed by the same operation as in Example 4 except that the isotropic resin film having a star shape obtained in Production Example 12 was used instead of the λ / 4 stretched resin film.

[0426] When observed with the naked eye, a mixed state of red, green, blue and silver regions generated by reflections of the sheets (R), (G), (B) and (S) is seen on the display surface. The isotropic resin film that is seen to be a star is a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped portion and other portions on the display surface is not seen, and it does not change with rotation.

[0427] Even when viewed through polarized sunglasses, the isotropic resin film that can be seen as a star is a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts of the display surface cannot be seen, and it does not change with rotation. Therefore, at any azimuth angle, the star shape cannot be seen more clearly than the naked eye.

[0428] [Comparative Example 3]

[0429] An identification medium was obtained and observed by the same operation as in Examples 1 and 2 except that aluminum foil was used instead of the cholesteric material layer as the light reflecting layer and the isotropic resin film having a star shape obtained in Production Example 12 was used instead of the λ / 4 stretched resin film.

[0430] When observed with the naked eye, silver color is seen on the display surface due to the reflection of the aluminum foil. The phase difference layer is seen as a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts on the display surface cannot be seen, and it does not change with rotation.

[0431] Even when viewed through polarized sunglasses, the isotropic resin film that can be seen as a star is a transparent member, and the star shape is almost invisible. The difference in brightness between the star-shaped part and other parts of the display surface cannot be seen, and it does not change with rotation. Therefore, at any azimuth angle, the star shape cannot be seen more clearly than the naked eye.

[0432] Description of Reference Numerals

[0433] 50: Identification medium; 200: Identification medium;

[0434] 100: identification medium; 201(Y): light reflection layer;

[0435] 101(R): light reflecting layer; 201(Y)U: upper portion of light reflecting layer 201(Y)

[0436] 101(R)U: upper surface of the light reflection layer 101(R);

[0437] Surface; 202: patterned phase difference layer;

[0438] 102: patterned phase difference layer; 202(N): isotropic layer;

[0439] 102(N): Isotropic layer; 202(Xy): Functions as a λ / 2 wave plate

[0440] 102 (Xy): a layer functioning as a λ / 4 wave plate;

[0441] 202U: patterned phase difference layer 202 side

[0442] 102U: the upper surface of the patterned phase difference layer 102 side;

[0443] Upper side surface; 501(P): light reflection layer of the slice;

[0444] 191(X): Linear polarizer for observation; 501(S): Silver light reflecting layer;

[0445] 191(Y): Linear polarizer for observation; 502: Phase difference layer;

[0446] 511: substrate; A125(Y): light;

[0447] 512: transparent substrate; A129(L): light;

[0448] 521: light absorbing layer; A191(X): arrow indicating the direction of the transmission axis

[0449] 531: diffusion membrane; head;

[0450] 541: transparent resin part; A211(X): light;

[0451] 542: transparent resin part; A211(Y): light;

[0452] 543: transparent resin part; A212(L): light;

[0453] 590: Mounting components; A212(R): Light;

[0454] 591: tray; A213(n): light;

[0455] 592: Ring; A213(R): Light;

[0456] A102(Xy): arrow indicating the direction of the slow axis; A214(n): light;

[0457] A111(N): light; A214(Y): light;

[0458] A112(N): light; A219(L): light;

[0459] A113(R): light; A219(n): light;

[0460] A114(Y): light; A221(X): light;

[0461] A115(n): light; A221(Y): light;

[0462] A115(Y): light; A222(X): light;

[0463] A119(L): light; A222(Y): light;

[0464] A121(N): light; A223(R): light;

[0465] A122(N): light; A224(R): light;

[0466] A123(R): light; A229(L): light;

[0467] A124(R): light; A311(N): light;

[0468] A125(X): Light; A312(N): Light;

[0469] A313(X): light; A421(Y): light;

[0470] A314(Y): light; A422(X): light;

[0471] A315(n): light; A422(Y): light;

[0472] A315(Y): light; A423(n): light;

[0473] A319(Y): light; A423(X): light;

[0474] A321(N): light; A424(n): light;

[0475] A322(N): Light; A424(X): Light;

[0476] A323(X): Light; A429(n): Light;

[0477] A324(X): Light; A429(Y): Light.

[0478] A325(n): light;

[0479] A325(X): Light;

[0480] A329(Y): light;

[0481] A411(X): light;

[0482] A411(Y): light;

[0483] A412(X): light;

[0484] A412(Y): light;

[0485] A413(n): light;

[0486] A413(X): light;

[0487] A414(n): light;

[0488] A414(Y): light;

[0489] A419(n): light;

[0490] A419(Y): light;

[0491] A421(X): light;

Claims

1. An identification medium comprising a light reflecting layer and a patterned phase difference layer, The light reflecting layer is a layer that reflects incident light into circularly polarized light. The patterned phase difference layer is a layer including an area with a phase difference, and the area with a phase difference is arranged on the identification medium in a manner that occupies a portion of the display surface of the identification medium. The patterned phase difference layer includes an area that functions as a λ / 4 wave plate as the area with a phase difference, and the patterned phase difference layer also includes an area occupied by an isotropic layer without a phase difference.

2. The identification medium according to claim 1, wherein: The patterned phase difference layer is provided at a position closer to the viewing side than the light reflecting layer.

3. The identification medium according to claim 1 or 2, wherein: The light reflecting layer is a reflective circular polarizer.

4. The identification medium according to claim 1 or 2, wherein: The identification medium has one or more independent patterned phase difference layers as the patterned phase difference layer, The independent pattern-shaped phase difference layer is composed of a region having a size smaller than the display surface of the identification medium and having a certain phase difference.

5. The identification medium according to claim 1 or 2, wherein: The identification medium includes a plurality of regions whose slow axis directions are irregularly different as the regions having phase differences.

6. The identification medium according to claim 1 or 2, wherein: The light reflecting layer includes two or more regions having different polarization states of reflected light.

7. The identification medium according to claim 1 or 2, wherein: In one or more regions of the light reflecting layer, the reflectance of the non-polarized light incident on the region is 35% to 50% at all wavelengths in a wavelength range of 420 nm to 650 nm.

8. The identification medium according to claim 1 or 2, wherein: The identification medium further includes a light absorbing layer at a position on the opposite side of the light reflecting layer to the viewing side.

9. The identification medium according to claim 1 or 2, wherein: The identification medium further includes a diffusion layer at a position closer to the viewing side than the patterned phase difference layer.

10. The identification medium according to claim 1 or 2, wherein: The identification medium further includes a transparent resin portion, and all or part of the components other than the transparent resin portion are embedded in the transparent resin portion.

11. The identification medium according to claim 1 or 2, wherein: The identification medium further includes a mounting member for mounting on an object. 12 . An article comprising the identification medium according to claim 1 .

13. The article of claim 12, wherein: The article also has a polarizer viewing device.

14. A method of use, which is a method of use of the identification medium according to any one of claims 1 to 11, The method of use includes: causing incident light to be incident on the display surface of the identification medium, being reflected by the light reflecting layer to form reflected light, and observing the reflected light; When non-polarized light is incident as the incident light and the reflected light is observed, a linear polarization component of the reflected light is selectively observed.

15. The method of use according to claim 14, wherein: The selective observation is performed by visually observing the reflected light through a linear polarizer separated from the identification medium.

16. The method of use according to claim 15, wherein: The linear polarizer is polarized sunglasses.

17. A method of use, which is a method of use of the identification medium according to any one of claims 1 to 11, The method of use includes: causing incident light to be incident on the display surface of the identification medium, being reflected by the light reflecting layer to form reflected light, and observing the reflected light; Linearly polarized light, circularly polarized light, or elliptically polarized light is caused to be incident as the incident light.

Images