JP5523127B2 - Identification medium and identification method thereof - Google Patents

Description

  The present invention relates to an identification medium used for determining the authenticity of a product, for example, and an identification method thereof.

  As an identification medium used for authenticity determination, there is known one that performs identification by allowing different images to be observed in observation through the left and right circularly polarizing filters (see, for example, Patent Document 1). This technology has a basic structure in which a light transmitting layer, a printing layer constituting a first pattern, and a cholesteric liquid crystal layer are laminated, and a hologram pattern (second pattern) is formed on the cholesteric liquid crystal layer by embossing. Yes.

JP 2009-172798 A

  In the identification medium having the above basic structure, it is assumed that the cholesteric liquid crystal layer has a characteristic of selectively reflecting the right-handed circularly polarized light. At this time, a case is considered in which a circular polarizing filter (left circular polarizing filter) that selectively transmits left-turn circularly polarized light is positioned away from the identification medium, and the identification medium is observed through the circular polarizing filter. In this case, right-handed circularly polarized light is reflected from the cholesteric liquid crystal layer, but it is not observed because it is blocked by the left-handed circularly polarizing filter. That is, the second pattern formed in the cholesteric liquid crystal layer cannot be observed.

  On the other hand, the reflected light from the printing layer is a component other than the right-handed circularly polarized light having a specific wavelength reflected by the cholesteric liquid crystal layer. Therefore, the reflected light of the first pattern is transmitted through the counterclockwise circularly polarizing filter and observed. That is, in this case, only the first symbol from the print layer is selectively visible.

  On the other hand, when the identification medium is observed through a circularly polarizing filter (right circularly polarizing filter) that selectively transmits right-handed circularly polarized light, right-handed circularly polarized light reflected from the cholesteric liquid crystal layer is reflected on the right circularly polarizing filter. The second design is visible. At the same time, the first pattern appears thin.

  Here, the reason why the first symbol is observed is as follows. In this case, components other than right-handed circularly polarized light having a specific wavelength are transmitted through the cholesteric liquid crystal layer. This transmitted light is reflected by the printing layer, passes through the cholesteric liquid crystal layer, and enters the right-turn circularly polarizing filter. Since this incident light includes a right-handed circularly polarized light component other than the specific wavelength reflected by the cholesteric liquid crystal layer, this component passes through the right-handed circularly polarized light filter, and the printed layer looks thin.

  Thus, in the above technique, the first design looks common in observation using the left and right circularly polarizing filters. On the other hand, in terms of the optical identification function, it is preferable that the image is clearly switched by switching between the left and right circularly polarizing filters.

  In such a background, an object of the present invention is to provide an identification medium in which clear switching of images can be observed.

According to one aspect of the present invention, from the observation side, and the cholesteric liquid crystal layer in which a hologram processing is performed, and a lens array layer having a plurality of lenses which are regularly arranged in a predetermined pattern, first a first optical pattern is arranged in association with the second optical pattern to a sequence of the plurality of lenses having a second color different from the optical pattern and the first color layer is disposed in the color, the When observed from an angle of 1, the focus of the lens array layer is aligned with the first optical pattern, and when observed from a second angle different from the first angle, the focus of the lens array layer is An identification medium that matches the second optical pattern .

  According to the first aspect of the invention, the function of the lens array layer allows the first optical pattern to be selectively seen at the specific first angle, and the second optical pattern at the specific second angle. Appears selectively, thereby switching the background color and appearance of the cholesteric liquid crystal layer. For this reason, clear switching of images in observation through the left and right circularly polarizing filters can be obtained.

  According to a second aspect of the present invention, in the first aspect of the invention, the first optical pattern or the second optical pattern is a pattern showing a specific color, and the cholesteric liquid crystal layer and the optical pattern A symbol layer in which a symbol having the same color as that of the first or second optical pattern is formed is disposed between the layers. According to the second aspect of the present invention, it is possible to further obtain an optical function in which the design of the design layer can be observed separately from the background at a certain angle and the design of the design layer can be observed at other angles.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the first optical pattern or the second optical pattern is a pattern showing a specific color, and the first optical pattern Or the said 2nd optical pattern is provided with the defect | deletion part which comprises a pattern. According to the third aspect of the present invention, it is possible to use, for identification, the symbols formed by the missing portions formed in the first color pattern or the second color pattern.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the lens array layer is a lenticular lens, and the optical pattern layer has a stripe pattern. And

  The invention according to claim 5 is the invention according to any one of claims 1 to 3, wherein the lens array layer is a microlens array in which a plurality of convex lenses are arranged vertically and horizontally, and the optical pattern layer is It has a dot pattern corresponding to the arrangement of the plurality of convex lenses.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the optical pattern layer is formed by printing on the lens array layer.

  The invention according to claim 7 is the invention according to claim 2, wherein the pattern layer is formed by printing on the lens array layer or the cholesteric liquid crystal layer.

  The invention according to claim 8 is a first step of observing the identification medium according to any one of claims 1 to 7 from the first angle through the left and right circularly polarizing filters, and claims 1 to 7. And a second step of observing the identification medium according to any one of 7 through the left and right circular polarization filters from a second angle.

  According to the first aspect of the present invention, the state of the appearance behind the cholesteric liquid crystal layer that displays the hologram image is clearly switched depending on the viewing angle. Therefore, when the observation is performed through the left and right circular polarizing filters. Due to a synergistic effect with the switching of the hologram image, an identification medium capable of observing a clear switching of the image is provided.

  According to the second aspect of the present invention, a higher identification function using the design of the design layer can be obtained.

  According to the third aspect of the present invention, a higher identification function using a pattern using a missing portion can be obtained.

  According to invention of Claim 4, the optical function which exhibits an identification function is obtained with respect to the angle change along a certain angle direction.

  According to the fifth aspect of the present invention, an optical function that exhibits an identification function can be obtained with respect to an angular change along two orthogonal angular directions.

  According to the invention described in claims 6 and 7, an identification medium having a simplified structure and a reduced thickness is provided.

  According to the eighth aspect of the present invention, there is provided an identification method using the identification medium of the present invention.

It is sectional drawing of the identification medium of embodiment. It is a principle figure which shows the principle of the optical function of embodiment. It is a front view of the stripe printing layer of an embodiment. It is sectional drawing of the identification medium of embodiment. It is a principle figure which shows the principle of the optical function of embodiment. It is sectional drawing of embodiment. It is a front view of the stripe printing layer of an embodiment. It is a principle figure which shows the principle of the optical function of embodiment. It is a front view of the stripe printing layer of an embodiment. It is a front view of the stripe printing layer of an embodiment. It is a conceptual diagram which shows the other example of a structure using a micro lens array.

1. First embodiment (configuration)
In the following, left-hand circularly polarized light is left-handed circularly polarized light, right-handed circularly-polarized light is right-handed circularly polarized light, an optical filter that selectively transmits left-handed circularly polarized light is left-handed circularly-polarized filter, and right-handed circularly-polarized light is selectively transmitted. The optical filter is called a right circular polarization filter.

  FIG. 1 shows an identification medium 100 of the embodiment. The identification medium 100 has a structure in which a cholesteric liquid crystal layer 101, a lenticular lens 102, a stripe print layer 103, an adhesive layer 104, and a separator 105 are laminated from the observation side.

  The cholesteric liquid crystal layer 101 has a characteristic of selectively reflecting right circularly polarized light having a green center wavelength. The selective reflection wavelength and the turning direction are not limited to this example, and may be left-handed circularly polarized light of another color such as red. The cholesteric liquid crystal layer 101 is subjected to hologram processing. Hologram processing is performed by pressing an emboss mold. In hologram processing, a hologram image is formed by the interference effect of reflected light generated by an embossed pattern. This hologram image is recognized by observing the reflected light from the cholesteric liquid crystal layer 101.

  The lenticular lens 102 is a lens array in which convex lenses having a semi-cylindrical cross section and extending in one direction are regularly arranged. FIG. 2 is a principle diagram for explaining the principle of the optical function of the lenticular lens 102 in the identification medium 100 of FIG. FIG. 2 shows a configuration in which the lenticular lens 102 is laminated on the stripe print layer 103.

  The stripe print layer 103 is an example of an optical pattern layer. The stripe printed layer 103 extends in the extending direction of the kamaboko-shaped convex lens constituting the lenticular lens 102, and further has a stripe pattern of color A and color B having an interval corresponding to the pitch of the arrangement of the kamaboko-shaped convex lens. It is the structure printed on the film. In this example, the kamaboko type convex lens constituting the lenticular lens 102 has a width of 0.0254 mm. The stripe printing layer is composed of white and black patterns, and the width of each of the white and black patterns is 0.0127 mm, which is half the width of the kamaboko type convex lens, and the total width of the adjacent white and black patterns Is set to be the width of the convex lens of the kamaboko type that forms the lenticular lens 102. The positional relationship between the lenticular lens 102 and the stripe printed layer 103 is set so that the boundary between the white and black patterns coincides with the center of the kamaboko convex lens.

  FIG. 3 shows a front view of the stripe print layer 103. Here, the white pattern is an example of the first optical pattern, and the black pattern is an example of the second optical pattern.

  If it is assumed that the cholesteric liquid crystal layer 101 does not exist, the position of the focal point of each convex lens constituting the lenticular lens 102 changes depending on the viewing angle when the stripe printed layer 103 is viewed from the lenticular lens 102 side. At a viewing angle of 1, a white pattern A is selectively visible, and at a second viewing angle, a black pattern B is selectively visible. At this time, in the observation from the first viewing angle, only the white pattern A is visible, so that the entire surface appears white. Further, in the observation from the second viewing angle, only the black pattern B is visible, so the entire surface appears black.

  Under the stripe print layer 103, an adhesive layer 104 made of an adhesive material is disposed. The identification medium 100 is affixed to an identification object (for example, various products) by the adhesive force exerted by the adhesive layer 104. FIG. 1 shows a state before the identification medium 100 is attached to the identification object. In this state, a separator 105 serving as a release paper is attached to the surface of the adhesive layer 104 that contacts the identification target. When fixing the identification medium 100 to the identification object, the separator 105 is peeled off, the adhesive layer 104 is exposed, and the adhesive layer 104 is brought into contact with the identification object. Each layer is fixed with a light-transmitting resin adhesive.

(Production method)
First, the cholesteric liquid crystal layer 101 is grown on an alignment substrate (not shown). Separately, a lenticular lens 102 and a stripe printing layer 103 are prepared. Then, the cholesteric liquid crystal layer 101 is peeled off from the alignment substrate and transferred to a light-transmitting film (for example, a TAC (triacetyl cellulose) film) made of a material that does not disturb the polarization state (not shown), and then subjected to hologram processing. Thereafter, the cholesteric liquid crystal layer 101 is laminated on the exposed surface of the lenticular lens 102 in a state where the above light-transmitting film (not shown) is the observation surface side. Here, each layer is fixed using a light-transmitting resin adhesive. Finally, the adhesive layer 104 and the separator 105 are formed, and the identification medium 100 is obtained.

(Optical function)
In a state where the identification medium 100 is observed from the cholesteric liquid crystal layer 101 side, when the identification medium 100 is tilted and an angle formed by the line of sight and the perpendicular of the identification medium 100 (hereinafter referred to as an angle at which this angle is viewed) is set to a certain value, lenticular. Depending on the function of the lens 102, only the white pattern A and only the black pattern B of the stripe printed layer 103 can be seen through the cholesteric liquid crystal layer 101. Here, when only the white pattern A is visible, the back (underground) of the cholesteric liquid crystal layer 101 is the entire white background. When only the black pattern B is visible, the back (underground) of the cholesteric liquid crystal layer 101 is the entire black background.

  Hereinafter, the viewing angle when only the white pattern A is the background of the cholesteric liquid crystal layer 101 is the first viewing angle, and the viewing angle when only the black pattern B is the background of the cholesteric liquid crystal layer 101 is the second viewing angle. And

(When observed at the first angle)
First, in the state in which the identification medium 100 is observed from the first angle, a case where the right circular polarization filter is positioned at a distance in front of the identification medium 100 and the identification medium 100 is observed through the right circular polarization filter will be described. . In this case, the background of the cholesteric liquid crystal layer 101 is a white background.

  At this time, natural light is incident on the cholesteric liquid crystal layer 101 from the observer side, and right circularly polarized light having a green central wavelength is reflected to the observer side. Other light components are transmitted through the cholesteric liquid crystal layer 101, reach the white pattern of the stripe printed layer 103, and are reflected there. The reflected light passes through the cholesteric liquid crystal layer 101 in the upper direction in FIG.

  The green right circularly polarized light selectively reflected from the cholesteric liquid crystal layer 101 passes through the right circular polarization filter between the identification medium 100 and the viewer and is visually recognized by the viewer. On the other hand, since the reflected light from the stripe printed layer 103 includes all polarization directions, it passes through the right circular polarization filter to the viewer side and is visually recognized by the viewer while receiving loss. As a result, the selected anti-oblique light (green right circularly polarized light) from the cholesteric liquid crystal layer 101 and the reflected light from the stripe printing layer 103 are simultaneously recognized. For this reason, the cholesteric liquid crystal layer 101 looks transparent with a white background, and a transparent hologram image with a white background is visible.

  Next, the case where the right circular polarizing filter is replaced with the left circular polarizing filter in the above state will be described. In this case, the selectively reflected light (green right circularly polarized light) from the cholesteric liquid crystal layer 101 is blocked by the left circularly polarizing filter and does not reach the observer. Therefore, the light reflected from the white pattern of the background stripe printed layer 103 is observed on the viewer side. Specifically, only the overall white background color is observed.

(When observed at the second angle)
Next, in the state in which the identification medium 100 is observed from the second angle, a case where the right circular polarization filter is positioned at a distance in front of the identification medium 100 and the identification medium 100 is observed through the right circular polarization filter will be described. To do. In this case, the background of the cholesteric liquid crystal layer 101 is a black background. Therefore, only selectively reflected light (green right circularly polarized light) from the cholesteric liquid crystal layer 101 is directed to the viewer side. This light passes through the right circular polarization filter and is visually recognized by the observer. Therefore, a green hologram image emerges in the black background and is observed.

  Next, the case where the right circular polarizing filter is replaced with the left circular polarizing filter in the above state will be described. In this case, the selectively reflected light (green right circularly polarized light) from the cholesteric liquid crystal layer 101 is blocked by the left circularly polarizing filter and does not reach the observer. Further, since the base is black, the background of the cholesteric liquid crystal layer 101 also appears black. Therefore, the whole looks black.

(Superiority)
As described above, the background color of the cholesteric liquid crystal layer is switched by changing the viewing angle by the function of the lenticular lens. For this reason, when the identification medium is observed from the first viewing angle through the right circular polarizing filter, a transparent hologram image can be seen against the white background, and when the viewing angle is the second viewing angle, The appearance changes as if a green hologram image appeared in a black background.

  Also, if the right circular polarizing filter is replaced with a left circular polarizing filter in this state, the whole appears to be black, and if the first viewing angle is set in this state, the whole appears white.

  In this way, by changing the combination of the viewing angle and the left and right circularly polarizing filters, an identification medium that can clearly see the switching of images is provided.

2. Second embodiment (configuration)
FIG. 4 shows an identification medium 200 according to the embodiment. The identification medium 200 is different from the identification medium 100 in FIG. 1 in that a design layer 201 is disposed between the cholesteric liquid crystal layer 101 and the lenticular lens 102. In other configurations, the identification medium 100 and the identification medium 200 are the same.

  The design layer 201 has a configuration in which a black design (color of the second optical pattern in the first embodiment) is printed on a light-transmitting resin film. The black symbols can be selected as long as they can be recognized, and patterns, figures, characters, and the like can be selected.

(Optical function)
FIG. 5 is a principle diagram showing the principle of the optical function of the identification medium 200 of FIG. In FIG. 5, the same parts as those in FIG. 2 are the same as those in FIG. The meanings of the first angle and the second angle are also the same as in the case of FIG. That is, the first angle is a case where the white pattern A is selectively seen by the function of the lenticular lens 102, and the second angle is a case where the black pattern B is selectively seen.

(When observed at the first angle)
First, in the state in which the identification medium 200 is observed from the first angle, a case where the right circular polarization filter is positioned at a distance in front of the identification medium 200 and the identification medium 200 is observed through the right circular polarization filter will be described. . In this case, the background of the cholesteric liquid crystal layer 101 is a white background. Therefore, the black symbol of the symbol layer 201 appears to appear in the white background.

  On the other hand, the cholesteric liquid crystal layer 101 reflects right-circularly polarized light having a center wavelength of green that is selectively reflected. Further, the light transmitted to the cholesteric liquid crystal layer 101 from the observation surface side to the stripe print layer 103 side is reflected by the white pattern of the stripe print layer 103, which again transmits the cholesteric liquid crystal layer 101 to the observation surface side.

  The green right circularly polarized light selectively reflected from the cholesteric liquid crystal layer 101 and the reflected light from the stripe printed layer 103 pass through the right circularly polarized filter and reach the observer. Accordingly, the cholesteric liquid crystal layer 101 shows a transparent hologram image with a white background, and at the same time, a green hologram image is observed overlapping the black symbol portion of the symbol layer 201.

  Next, the case where the right circular polarizing filter is replaced with the left circular polarizing filter in the above state will be described. In this case, the selectively reflected light (green right circularly polarized light) from the cholesteric liquid crystal layer 101 is blocked by the left circularly polarizing filter and does not reach the observer. Therefore, only the light reflected from the white pattern of the background stripe print layer 103 and the black pattern of the pattern layer 201 are observed. That is, only the black symbol of the symbol layer 201 is observed in the white background.

(When observed at the second angle)
Next, in the state where the identification medium 200 is observed from the second angle, a case where the right circular polarization filter is positioned at a distance in front of the identification medium 200 and the identification medium 200 is observed through the right circular polarization filter will be described. To do. In this case, the background of the cholesteric liquid crystal layer 101 is a black background. Therefore, the black symbol of the symbol layer 201 is buried in the background and cannot be visually recognized. On the other hand, the selectively reflected light (green right circularly polarized light) from the cholesteric liquid crystal layer 101 passes through the right circularly polarized light filter and reaches the observer side. Therefore, a green hologram image is selectively observed in a black background.

  Next, the case where the right circular polarizing filter is replaced with the left circular polarizing filter in the above state will be described. In this case, the selectively reflected light (green right circularly polarized light) from the cholesteric liquid crystal layer 101 is blocked by the left circularly polarizing filter and does not reach the observer. Further, since the background is uniformly black as a whole, the design of the design layer 201 cannot be visually recognized, and the background of the cholesteric liquid crystal layer 101 also appears black. Therefore, the entire identification medium 200 looks black.

(Superiority)
In the identification medium 200, compared to the identification medium 100, the identification medium 201 can be further used for identification, and an identification medium that can observe a clearer image change is provided. It is also possible to reverse the lightness and darkness of the symbol of the symbol layer 201 so that the symbol is composed of a white pattern.

3. Third Embodiment In the identification medium 100 of FIG. 1 or the identification medium 200 of FIG. 4, a microlens array can be used instead of a lenticular lens. The microlens array is a lens array in which convex lenses are arranged vertically and horizontally.

  FIG. 6 shows an identification medium 300 using a microlens array. The identification medium 300 has a structure in which the microlens array 301 is employed instead of the lenticular lens 102 in the identification medium 100 of FIG.

  In the identification medium 300, the dot print layer 302 is disposed in a portion corresponding to the stripe print layer 103 in FIG. FIG. 7 shows a front view of the dot print layer 302. In this example, a black circle dot pattern is employed as the first optical pattern. In this case, the portion other than the black dot is the second optical pattern.

  FIG. 8 is a principle diagram showing the principle of the optical function of the microlens array in the identification medium 300 of FIG. As shown in FIG. 8, in this example, the first angle is when the identification medium 300 is viewed from the vertical direction (front direction). In this case, the microlens is focused on the black dot A, When viewed from the second angle (oblique angle), the focus of the microlens is set to match the region B (white region) that is a region other than the dot A.

  In this case, when the identification medium 300 is observed from the first angle, the entire background of the cholesteric liquid crystal layer 101 is a black background. When the identification medium 300 is observed from the second angle, the entire background of the cholesteric liquid crystal layer 101 is a white background.

  Therefore, when the identification medium 300 is observed from the first angle through the right circular polarizing filter, the reflected light from the cholesteric liquid crystal layer 101 emerges against a black background, and the green right circle reflected from the cholesteric liquid crystal layer 101 is reflected. Polarized light appears selectively. That is, a green hologram image is observed in a black background.

  Further, when the identification medium 300 is observed from the first angle through the left circular polarization filter, the reflected light from the cholesteric liquid crystal layer 101 is blocked by the left circular polarization filter, and the whole looks black.

  On the other hand, when the identification medium 300 is observed from the second angle through the right circular polarizing filter, white reflected light from the background of the cholesteric liquid crystal layer 101 is preferential, and a transparent hologram image (cholesteric liquid crystal with white as a background) is obtained. A hologram image of the layer) is observed.

  When the identification medium 300 is observed from the second angle through the left circular polarization filter, the reflected light from the cholesteric liquid crystal layer 101 is blocked by the left circular polarization filter and the hologram image cannot be seen. On the other hand, in this case, since the light reflected by the background is transmitted through the left circular polarization filter, the whole appears to be uniform and whitish.

  In the third embodiment, a structure in which a design layer 201 as shown in FIG. 4 is interposed between the cholesteric liquid crystal layer 101 and the microlens array 301 is also possible. In this case, by configuring the design of the design layer in black, the black design of the design layer can be used as an identification target.

4). Fourth Embodiment In the identification medium 100 of FIG. 1, the stripe print layer 103 can be as shown in FIG. FIG. 9 shows a stripe print layer 103A that can be used instead of the stripe print layer 103 of FIG. In the stripe printed layer 103A, a black pattern portion is a partially defective portion, and a pattern extracted in white on an annular pattern is formed by the defective portion.

  When the identification medium 100 (see FIG. 1) provided with the stripe printed layer 103A is observed from a second angle (see FIG. 2), the circular whitened portion appears white, so that the background of the cholesteric liquid crystal layer 101 is entirely covered. Instead of black, the background pattern is in a state of being extracted in a white ring shape with a black background.

  Therefore, when the identification medium 100 is viewed from the second angle through the right circular polarizing filter, reflected light (hologram image) from the cholesteric liquid crystal 101 and a white ring-shaped pattern can be seen. Further, when the identification medium 100 is viewed from the second angle through the left circular polarizing filter, the reflected light (hologram image) from the cholesteric liquid crystal 101 is not visible, and a white ring-shaped pattern is visible on the black background. .

  Note that when the identification medium 100 is viewed from the first angle, the background of the cholesteric liquid crystal layer 101 is entirely white, so an annular pattern is not visible. It will be the same.

  Further, when the stripe print layer 103B of FIG. 10 is used instead of the stripe print layer 103 of FIG. 1, a black circular pattern can be seen in the white background at the first viewing angle, and at the second viewing angle, The circular design is not visible and the whole appears black.

  Here, an example in which a ring-shaped pattern is used has been described. However, a pattern configured using a stripe print layer may be a character or a pattern.

(Other)
Hereinafter, other configurations and possible configurations in the above examples will be described. The combination of the first color and the second color is not limited to the combination of white and black, and may be a combination that can clearly recognize the color difference. Examples of this combination include a combination of dark and light colors, a combination of metallic luster and dark colors, and a combination of red and blue. The widths of the two color patterns constituting the stripe print layer 103 are not the same and may be different values. For example, when the width of the white pattern is increased, the angle range in which the white pattern is selectively visible is widened, and when the width of the black pattern is increased, the angle range in which the black pattern is selectively visible is widened.

  In the dot pattern of FIG. 7, white and black are reversed, and a configuration in which white dots are arranged in a black background is also possible. In addition, a dot pattern can be formed using two colors that can be clearly distinguished instead of white and black. For example, a configuration in which a red dot pattern is formed in a blue background is possible.

  In the configuration shown in FIG. 1, the stripe print layer 103 can also be configured by a print layer printed on the back side of the lenticular lens 102. In the configuration shown in FIG. 4, the pattern layer 201 can be formed by printing on the back side of the cholesteric liquid crystal layer 101 or the surface of the lenticular lens 102. According to these configurations, the structure is simplified and the whole is thinned.

  The values of the first viewing angle and the second viewing angle are the width of the pattern constituting the stripe pattern of the stripe printing layer with respect to the lenticular lens (in the example of FIG. 2, the width of the pattern A and the pattern B) and the position. It is adjusted by adjusting. Accordingly, the pattern A can be selectively observed when the viewing angle is 0 ° (observation from the front), and the pattern B can be selectively viewed as the viewing angle is increased (observation from an oblique direction). Is possible.

  In the above illustration, the example of the pattern which shows specific colors, such as white and black, was demonstrated as an optical pattern of an optical pattern layer. Examples of other optical patterns include a configuration in which the first optical pattern is a light transmission pattern and the second optical pattern is a reflection pattern or a light absorption pattern. For example, in the stripe printed layer 103 shown in FIG. 3, an example in which a white pattern A is used as a light transmission pattern can be given. In this case, an optical pattern layer having a transmission pattern and a black pattern (light absorption pattern) as an optical pattern is obtained.

  In this case, the stripe print layer is produced by printing a black pattern B on a light transmissive resin film. Hereinafter, an example of the identification medium using the stripe print layer having the transmission region will be described. In this case, a transparent material is selected as the adhesive layer 104 in the configuration shown in FIG.

  When the identification medium is affixed to the identification object, when observed from the first viewing angle in FIG. 2, the transparent pattern of the stripe printed layer is selectively visible, and the surface of the identification object underneath is visible. Is visually recognized as the background of the cholesteric liquid crystal layer 101. Further, by setting the viewing angle to the second angle, the black pattern of the stripe printed layer appears selectively, and the background of the cholesteric liquid crystal layer 101 appears black.

  The structure in which the light transmission pattern layer is provided on the optical pattern layer can be used for the structure using the microlens array shown in FIGS. In this case, instead of the dot printing layer 302, an optical pattern layer in which a light transmission pattern is provided in the dot pattern and the other area is used as a light reflection pattern or a light absorption pattern is used. Further, instead of the dot printing layer 302, an optical pattern layer in which a light reflection pattern or a light absorption pattern is provided in the dot pattern and the other region is a light transmission pattern can be used.

  FIG. 11 is a conceptual diagram showing another example of a configuration using a microlens array. FIG. 11 conceptually shows the state of the design of one convex lens constituting the microlens array and the dot print layer corresponding to this convex lens.

  FIG. 11 shows a convex lens 401 and dot printing layers 402, 403, and 404 below the convex lens 401. First, FIG. 11A shows an example of a simple dot pattern (an example similar to FIGS. 7 and 8). In this case, two colors are selectively observed corresponding to the viewing angle (1) and the viewing angle (2).

  In the case of FIGS. 11B and 11E, different colors can be observed at three angle positions of viewing angles (1), (2), and (3). That is, the colors are switched in multiple stages depending on the angle of inclination. In the case of FIG. 11C and FIG. 11F, a plurality of different colors are selectively observed depending on the tilting direction.

  When the technique shown in FIG. 11 is used, three or more different colors can be used as the background of the cholesteric liquid crystal layer, and the switching of images depending on the viewing angle becomes more complicated. For this reason, a higher identification function can be obtained. Here, an example has been described in which the color is switched in multiple stages, but it is also possible to incorporate a transmission state and a glossy reflection state therein.

  In the various examples of the present invention described above, the content of the hologram image or design is not particularly limited as long as it can be distinguished, and can be appropriately selected from figures, characters, numbers, various designs, patterns, and the like. it can.

  The article to which the identification medium is affixed is not particularly limited as long as it is necessary to identify a counterfeit product (identification of authenticity). Examples of such articles include credit cards, passports, securities, various product packages, licenses, ID cards, clothing, tags attached to products, small items, electronic devices, various consumables, and the like.

  Further, in the description of the embodiment, the case where the observation optical filter (circular polarization filter) is positioned at a position away from the identification medium and observation for identification is performed has been described. You may observe in the state which made the polarizing filter contact the identification medium.

  The present invention can be used in a technique for identifying authenticity.

  DESCRIPTION OF SYMBOLS 100 ... Identification medium, 102 ... Lenticular lens, 103 ... Stripe printed layer, 104 ... Adhesive layer, 105 ... Separator.

Claims (8)

From the observing side
A cholesteric liquid crystal layer with hologram processing;
A lens array layer comprising a plurality of lenses regularly arranged in a predetermined pattern;
An optical pattern layer and the second optical patterns are arranged so as to correspond to the arrangement of the plurality of lenses having a second color different from the first optical pattern and the first color of the first color are arranged ,
When observed from a first angle, the lens array layer is focused on the first optical pattern,
An identification medium , wherein the lens array layer is focused on the second optical pattern when observed from a second angle different from the first angle .
The first optical pattern or the second optical pattern is a pattern showing a specific color,
2. The identification according to claim 1, wherein a design layer in which a design of the same color as the first or second optical pattern is formed is disposed between the cholesteric liquid crystal layer and the optical pattern layer. Medium. The first optical pattern or the second optical pattern is a pattern showing a specific color,
The identification medium according to claim 1 or 2, wherein a defect portion constituting a symbol is provided in the first optical pattern or the second optical pattern. The lens array layer is a lenticular lens;
The identification medium according to claim 1, wherein the optical pattern layer has a stripe pattern. The lens array layer is a microlens array in which a plurality of convex lenses are arranged vertically and horizontally,
The identification medium according to claim 1, wherein the optical pattern layer has a dot pattern corresponding to the arrangement of the plurality of convex lenses.   The identification medium according to claim 1, wherein the optical pattern layer is formed by printing on the lens array layer.   The identification medium according to claim 2, wherein the pattern layer is formed by printing on the lens array layer or the cholesteric liquid crystal layer. A first step of observing the identification medium according to any one of claims 1 to 7 from the first angle through the left and right circularly polarizing filters;
And a second step of observing the identification medium according to any one of claims 1 to 7 through the left and right circularly polarizing filters from a second angle.

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