JP2009098454A - Optical device, optical kit and printed matter with label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device which takes in new element for forgery prevention determination by providing two layer structure formed by laminating a right polarized light reflecting layer and a left polarized light reflecting layer and thereby which have further forgery prevention effect, more decorating effect and more esthetic effect and to provide an optical kid and a printed matter with a label using the optical device. <P>SOLUTION: A colored layer 12 is formed on a base material 11. On the colored layer 12, the right polarized light reflecting layer 13 for reflecting dextrorotary polarized light among incident light and the left polarized light reflecting layer 14 for reflecting levorotatory polarized light among incident light are formed. At the right polarized light reflecting layer 13 and the left polarized light reflecting layer 14, a part 102 where both layers mutually overlap is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical element having an anti-counterfeit effect, a decorative effect, and an aesthetic effect, an optical kit, and a printed matter with a label.

Conventionally, a latent image has been used as one method of preventing forgery.
There are various methods for forming a latent image. For example, it can be formed using line moire or intaglio printing.
A latent image using line moire is obtained by superimposing an image to be a latent image and a large number of lines arranged at high density. This image makes it difficult to identify a large number of lines when observed with the naked eye, and the identification is facilitated by hiding these lines. A latent image using intaglio printing is obtained by providing a concave pattern and / or a convex pattern in the ink layer. An image formed by a concave pattern and / or a convex pattern is difficult to identify when viewed from the front, and is visualized by observing from an oblique direction.
The latent image technology using line moire or intaglio printing is relatively easy to determine authenticity. However, images formed by these methods are not necessarily indistinguishable when observed with the naked eye. Therefore, these latent images are easy to realize their own existence.

The latent image can also be formed with special inks such as fluorescent ink and infrared absorbing ink.
The fluorescent ink is an ink that emits light when irradiated with ultraviolet rays, and a latent image formed using the fluorescent ink is visualized when irradiated with ultraviolet rays. The infrared absorbing ink is an ink having a high infrared absorption rate, and a latent image formed using the infrared absorbing ink is visualized by observing with an infrared camera, for example.
Latent images formed using special inks are difficult to realize. However, the visualization requires an apparatus such as an ultraviolet lamp or an infrared camera.

On the other hand, cholesteric liquid crystal is used as another method for preventing forgery.
The cholesteric liquid crystal itself exhibits a characteristic color, and the observed color changes depending on the viewing angle. Therefore, the cholesteric liquid crystal has an effect of preventing simple forgery due to color copying or the like. In addition, it has the feature of reflecting either the clockwise or counterclockwise circularly polarized light, and it can also be provided with a verification function using a circularly polarizing filter, so a single material can be combined to prevent counterfeiting. Can be realized.
For example, Patent Document 1 proposes a latent image technique using a cholesteric liquid crystal. Thus, combining a plurality of anti-counterfeit technologies is very effective because the anti-counterfeit effect is improved.
However, progress in counterfeiting technology is significant. Therefore, further progress is desired in anti-counterfeiting technology.
JP 2003-170649 A

  However, in the latent image technology using the conventional cholesteric liquid crystal disclosed in Patent Document 1, a right polarization reflection layer that reflects right-handed polarized light in incident light and a left-handed left polarized light that reflects left-handed polarized light in incident light. Each of the polarizing reflective layers was printed in a separate area on the substrate. For this reason, the determination of anti-counterfeiting has been limited to two types: determination of the right polarization reflection layer and determination of the left polarization reflection layer.

  The present invention has been made in view of such circumstances, and its purpose is to provide a new structure for determining forgery prevention by providing a two-layer structure in which a right polarization reflection layer and a left polarization reflection layer are overlapped. Incorporating the elements, and thus providing an optical element, an optical kit and a labeled printed matter having further anti-counterfeiting effects, decorative effects and aesthetic effects.

In order to achieve the above object, an optical element of the present invention is formed on a base material, a right polarization reflection layer that is formed on the base material and reflects right-handed polarized light of incident light, and the base material. And a left polarization reflection layer that reflects left-rotated polarized light in the incident light, and the right polarization reflection layer and the left polarization reflection layer are provided with overlapping portions overlapping each other.
The optical kit of the present invention includes an optical element, a right circularly polarizing filter that transmits clockwise circularly polarized light, and a left circularly polarizing filter that transmits counterclockwise circularly polarized light. A right polarization reflecting layer that is formed on the substrate and reflects right-rotation polarized light out of incident light; and a left polarization that is formed on the substrate and reflects left-rotation polarized light out of the incident light. The right polarization reflection layer and the left polarization reflection layer are provided with overlapping portions that overlap each other.
Moreover, the printed matter with a label according to the present invention includes an optical element and a printed matter on which the optical element is attached as a label. The optical element is formed on a base material and the base material. A right polarization reflection layer that reflects right-rotation polarized light; and a left polarization reflection layer that is formed on the substrate and reflects left-rotation polarization of incident light. The right polarization reflection layer and the left The polarized light reflecting layer is provided with overlapping portions overlapping each other.

According to the optical element, the optical kit, and the printed matter with a label of the present invention, the right polarization reflection layer and the left polarization reflection layer are formed on the substrate, and the right polarization reflection layer and the left polarization reflection layer overlap each other. A part is provided.
Therefore, for the determination of anti-counterfeiting by the two-layer structure in which the right-polarization reflection layer and the left-polarization reflection layer overlap with the elements for the conventional anti-counterfeiting determination by the right polarization reflection layer and the left polarization reflection layer of a single layer New elements are added. Therefore, it is possible to provide an optical element, an optical kit, and a printed matter with a label having further anti-counterfeiting effects, decorative effects, and aesthetic effects.

Hereinafter, an optical element, an optical kit, and a printed matter with a label of the present invention will be described with reference to the drawings.
An optical element according to an embodiment of the present invention includes a base material, a right polarization reflecting layer that is formed on the base material and reflects right-rotation polarized light out of incident light, and is formed on the base material and incident light. And a left polarization reflection layer that reflects left-handed polarized light, and the right polarization reflection layer and the left polarization reflection layer are provided with overlapping portions.

FIG. 1 is a plan view schematically showing an optical element according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II of the optical element shown in FIG.
The optical element 10 is to be confirmed to be a genuine product, and includes a display unit 101 and a display unit 102 when the optical element 10 is viewed from the front as shown in FIG.
As shown in FIG. 2, the optical element 10 includes a base material 11, a colored layer 12 formed on the base material 11, and a left polarization reflection formed in a T shape on a part of the colored layer 12. And a right polarization reflection layer 13 formed on the colored layer 12 and the left polarization reflection layer 14.

  The front surface of the optical element 10 is the upper surface of the left polarization reflection layer 13 that is the uppermost layer of the substrate 11. The right polarization reflection layer 13 and the left polarization reflection layer 14 are provided with overlapping portions 102 that overlap each other. The display unit 102 is a superposed portion 102 where the right polarization reflection layer 13 and the left polarization reflection layer 14 are overlapped, and the display unit 101 is a portion where only the right polarization reflection layer 13 is formed.

The substrate 11 is a sheet of resin such as polyethylene terephthalate (PET) or paper.
The colored layer 12 is used to sharpen the colors of the right polarization reflection layer 13 and the left polarization reflection layer 14 as viewed from the front side of the optical element 10. For example, screen printing or gravure using black ink is used. It is formed by printing, microgravure printing or the like.

  The right polarization reflection layer 13 is made of a cholesteric liquid crystal material having a solidified right-handed spiral structure. The right polarization reflection layer 13 is formed by non-fluidizing a cholesteric liquid crystal material having fluidity. The left polarization reflection layer 14 is made of a cholesteric liquid crystal material having a solidified left-handed spiral structure. The left polarization reflection layer 14 is formed by non-fluidizing a cholesteric liquid crystal material having fluidity.

  The right polarization reflection layer 13 and the left polarization reflection layer 14 are typically polymer cholesteric liquid crystal layers formed by curing a polymerizable cholesteric liquid crystal material having fluidity with ultraviolet rays or heat.

  The cholesteric liquid crystal has a layer structure and has a spiral structure in which the alignment direction of liquid crystal molecules is regularly twisted in the film thickness direction. Specifically, the director (average orientation direction) n of the liquid crystal molecules is in a certain direction in a certain plane, but the direction of n is somewhat twisted in an adjacent plane parallel to this plane. The inter-surface distance for n to rotate 360 ° is the spiral pitch P of the cholesteric liquid crystal.

  In the cholesteric liquid crystal, the refractive index of light periodically changes along its spiral axis. It is known that when the helical pitch P at that time and the wavelength of incident light are substantially equal, two optical properties of selective reflection and circular polarization selectivity are exhibited. That is, it has the property of reflecting circularly polarized light whose wavelength is equal to the helical pitch and in the same direction as the helical twist. Therefore, it is possible to obtain a desired reflected color by controlling the pitch of the spiral structure, and since a component in a specific wavelength region is reflected, reflected light with high color purity can be obtained.

  The orientation of each molecule can be controlled by a known method such as an orientation layer or an electric field or a magnetic field. In addition, as a typical method of immobilization, a three-dimensional cross-linkable liquid crystal substance having a chiral phase and a polyfunctional polymerizable compound are combined and irradiated with ultraviolet rays, so that three-dimensional cross-linking can be achieved and the helical structure can be immobilized. A polymer cholesteric liquid crystal is obtained.

The polymer cholesteric liquid crystal layer can be formed, for example, by the following method.
First, a cholesteric liquid crystal material having photopolymerizability is applied on the colored layer 12. At this time, when a liquid crystal material is applied in a pattern using a printing method such as screen printing, gravure printing, offset printing, or flexographic printing, a cholesteric liquid crystal layer can be formed only in a necessary portion. The liquid crystal material is then irradiated with ultraviolet light to cause their polymerization. Thereby, the right polarization reflection layer 13 and the left polarization reflection layer 14 which are polymer cholesteric liquid crystal layers in which the helical structure is fixed can be obtained.

The cholesteric liquid crystal material may be the cholesteric liquid crystal material itself, or a cholesteric liquid crystal material that is solidified and then pulverized and pigmented may be used. By making it into a pigment, kneading with various binders, dispersants, auxiliaries and the like is possible, and the characteristics as inks used in various printing such as gravure printing and screen printing can be improved.
It is desirable that the hues of the cholesteric liquid crystal materials used for the right polarization reflection layer 13 and the left polarization reflection layer 14 are the same.

  Next, an image that is seen when the optical element 10 is irradiated with white light and observed with the naked eye will be described. White light is light composed of non-polarized light with all wavelengths in the visible region.

FIG. 3 is a plan view showing an example of an image displayed by the optical element shown in FIGS. 1 and 2.
When the optical element 10 is irradiated with white light and observed with the naked eye, the display units 101 and 102 cannot or cannot be distinguished from each other as shown in FIG. This will be described in more detail.

  As for the white light as the illumination light incident on the display unit 101, only the right circularly polarized light is reflected by the right polarization reflection layer 13 shown in FIG. At this time, the left circularly polarized light passes through the right polarized light reflection layer 13 and is absorbed by the colored layer 12. That is, the display unit 101 observes the right circularly polarized light reflected from the right polarized light reflecting layer 13.

Only the right circularly polarized light is reflected by the right polarization reflection layer 13 shown in FIG. At this time, the left circularly polarized light passes through the right polarized light reflecting layer 13 and enters the left polarized light reflecting layer 14. The left circularly polarized light incident on the left polarization reflection layer 14 is reflected by the left polarization reflection layer 14. That is, the display unit 102 observes the right circularly polarized light reflected from the right polarized light reflecting layer 13 and the left circularly polarized light reflected from the left polarized light reflecting layer 14.
Since the human eye cannot recognize the difference in the rotation direction of the circularly polarized light, the display unit 101 and the display unit 102 appear to be the same color, for example, red, and cannot be distinguished from each other.

  In order to make the discrimination between the display unit 101 and the display unit 102 more difficult, for example, the right polarization reflection layer 13 forming the display unit 102 may be provided by halftone printing. Halftone printing refers to the provision of ink in the form of dots in printing methods such as screen printing and offset printing. If the right polarization reflection layer 13 is provided by halftone printing, the boundary line with the left polarization reflection layer 14 becomes difficult to understand, and the discrimination can be made more difficult.

  Further, in order to make the discrimination between the display unit 101 and the display unit 102 more difficult, for example, a print pattern such as a tint block pattern can be further superimposed on the left polarization reflection layer 14 forming the display unit 101. By overlapping the print patterns, the boundary line between the right polarization reflection layer 13 and the left polarization reflection layer 14 becomes difficult to understand, making discrimination more difficult and further improving the design.

FIG. 4 is a conceptual diagram illustrating an example of an observation method of the optical element illustrated in FIGS. 1 and 2.
As shown in FIG. 4, when the observation direction is tilted in a plane perpendicular to the X direction from the state shown in FIG. 3, the display colors of the display units 101 and 102 change. For example, if the display units 101 and 102 are viewed in red when observed from the normal direction 20, the viewing directions of the display units 101 and 102 are tilted from the viewpoints 21 to 25 in a plane perpendicular to the X direction. The color changes in order of orange, yellow, green, blue-green, and blue. The reason for the color change that occurs in the display units 101 and 102 will be described below.

  When white light as illumination light is incident obliquely, the helical pitch is apparently reduced, and the center wavelength of the reflected light is shifted to the short wavelength side (blue shift). The shift amount depends on the incident angle. Therefore, when the optical element 10 is tilted in a plane perpendicular to the X direction, for example, the reflected color of the cholesteric liquid crystal that appears red when viewed from the normal direction 20 becomes orange, yellow, or green as the tilt angle increases. , Blue-green and blue.

  Next, an image that is seen when the optical element 10 is observed through a polarizing filter will be described. Here, the left circular polarizing film 50 is used as the polarizing filter. The left circularly polarizing film 50 is a polarizing filter designed to transmit counterclockwise circularly polarized light.

FIG. 5 is a plan view schematically showing an example of an image that can be observed when the optical element 10 shown in FIGS. 1 and 2 and the left circularly polarizing film 50 are overlapped.
In FIG. 5, the optical element 10 and the left circularly polarizing film 50 shown in FIGS. 1 and 2 are overlapped. When this is observed from the front, the display unit 101 and the display unit 102 can be easily distinguished from each other as shown in FIG. This will be described in more detail.

  As for the white light as the illumination light incident on the display unit 101, only the right circularly polarized light is reflected by the right polarization reflection layer 13 shown in FIG. At this time, the left circularly polarized light passes through the right polarized light reflection layer 13 and is absorbed by the colored layer 12. That is, the display unit 101 observes the right circularly polarized light reflected from the right polarized light reflection layer 13. When this is observed through the left circularly polarizing film 50, the right circularly polarized light cannot be transmitted through the left circularly polarizing film 50, so that the display unit 101 looks black.

  Only the right circularly polarized light is reflected by the right polarization reflection layer 13 shown in FIG. At this time, the left circularly polarized light passes through the right polarized light reflecting layer 13 and enters the left polarized light reflecting layer 14. The left circularly polarized light incident on the left polarization reflection layer 14 is reflected by the left polarization reflection layer 14. That is, the display unit 102 observes the right circularly polarized light reflected from the right polarized light reflecting layer 13 and the left circularly polarized light reflected from the left polarized light reflecting layer 14. When this is observed through the left circularly polarizing film 50, the left circularly polarized light reflected from the left polarizing reflective layer 14 is transmitted, and the display unit 102 looks red, for example.

Thus, the display unit 101 appears black and the display unit 102 appears colored. Therefore, when the polarizing film 50 is overlaid on the optical element 10 and irradiated with white light and observed from the front, the display units 101 and 102 can be easily distinguished as shown in FIG.
Further, in the display unit 102, the same color change as described with reference to FIG. 4 can be observed through the left circularly polarizing film 50.

  Next, another example of an image seen when the optical element 10 is observed through a polarizing filter will be described. Here, the right circular polarizing film 60 is used as the polarizing filter. The right circularly polarizing film 60 is a polarizing filter designed to transmit clockwise circularly polarized light.

FIG. 6 is a plan view schematically showing an example of an image that can be observed when the optical element 10 shown in FIGS. 1 and 2 and the linearly polarizing film 60 are overlapped.
In FIG. 6, the optical element 10 and the right circularly polarizing film 60 shown in FIGS. When this is observed from the front, as shown in FIG. 6, it is impossible or difficult to distinguish the display unit 101 and the display unit 102 from each other. This will be described in more detail.

  As for the white light as the illumination light incident on the display unit 101, only the right circularly polarized light is reflected by the right polarization reflection layer 13 shown in FIG. At this time, the left circularly polarized light passes through the right polarized light reflection layer 13 and is absorbed by the colored layer 12. That is, the display unit 101 observes the right circularly polarized light reflected from the right polarized light reflection layer 13. When this is observed through the right circularly polarizing film 60, the right circularly polarized light is transmitted through the right circularly polarizing film 60, so that the display unit 101 looks red, for example.

  Only the right circularly polarized light is reflected by the right polarization reflection layer 13 shown in FIG. At this time, the left circularly polarized light passes through the right polarized light reflecting layer 13 and enters the left polarized light reflecting layer 14. The left circularly polarized light incident on the left polarization reflection layer 14 is reflected by the left polarization reflection layer 14. That is, the display unit 102 observes the right circularly polarized light reflected from the right polarized light reflecting layer 13 and the left circularly polarized light reflected from the left polarized light reflecting layer 14. When this is observed through the right circularly polarizing film 60, the right circularly polarized light reflected from the right polarized light reflecting layer 13 is transmitted, and the display unit 102 looks red, for example.

Thus, the display units 101 and 102 appear colored. Therefore, when the right circularly polarizing film 60 is placed on the optical element 10 and irradiated with white light and observed from the front, it is impossible or difficult to distinguish between the display units 101 and 102 as shown in FIG.
Further, in the display units 101 and 102, the same color change as described with reference to FIG.

When the observations of the display units 101 and 102 are summarized, the following features effective for authenticity determination are recognized.
(1) The display units 101 and 102 display substantially the same color when observed from the normal direction without the left circular polarizing film 50 and the right circular polarizing film 60.
(2) The display units 101 and 102 were observed from the normal direction without the left circular polarizing film 50 and the right circular polarizing film 60, and observed from the oblique direction without the left circular polarizing film 50 and the right circular polarizing film 60. The same color change is shown.
(3) The display units 101 and 102 display different colors when observed from the normal direction through the left circularly polarizing film 50.
(4) The display units 101 and 102 display different colors when observed from an oblique direction through the left circular polarizing film 50.
(5) The display unit 102 displays different colors when observed from the normal direction through the left circular polarizing film 50 and when observed from the oblique direction through the left circular polarizing film.
(6) When the display units 101 and 102 are observed from the normal direction through the right circularly polarizing film 60, the display units 101 and 102 display substantially equal colors.
(7) The display units 101 and 102 display substantially the same color when viewed from an oblique direction through the right circular polarizing film 60.
(8) The display unit 102 displays substantially the same color when observed from the normal direction through the right circular polarizing film 60 and when observed from the oblique direction through the right circular polarizing film.

  When a labeled printed matter comprising the optical element 10 and a printed matter on which the optical element 10 is attached as a label is an authentic product, an article whose authenticity is unknown indicates one or more of the above features. If not, it can be determined that the article is non-genuine. That is, it is possible to discriminate between an authentic product and an unauthentic product for an article whose authenticity is unknown.

The printed material is, for example, securities, banknotes, identification cards, and credit cards, and proof that they are authentic products is necessary. Here, by attaching the optical element of the present invention as a label, forgery of printed matter, artwork, and various articles can be prevented or suppressed. Here, the label refers to a processed product for attaching the optical element of the present invention, such as a sticker seal or a transfer foil attached by hot pressure.
Further, the optical kit including the optical element 10 and the right circular polarizing film 50 and the left circular polarizing film 60 can be used as a toy, a learning material, or a decoration, in addition to being usable for the previous authenticity determination. can do.

The optical element 10 may further include a protective layer and an adhesive layer described below.
FIG. 7 is a sectional view showing a modification of the optical element shown in FIG.
The optical element 10 shown in FIG. 7 has the same structure as the optical element 10 described with reference to FIGS. 1 and 2 except that it further includes a protective layer 15 that covers the right polarized light 13. . When the protective layer 15 is provided, it is possible to make it difficult to cause damage and light deterioration of the right polarization reflection layer 13 and the like, and therefore, it is possible to suppress deterioration of an image displayed by the optical element 10.
As a material for the protective layer 15, for example, a hard coat material having excellent scratch resistance can be used. Moreover, as a material of the protective layer 15, a highly transparent material is typically used. The protective layer 15 may be colorless and transparent, or may be colored and transparent.

FIG. 8 is a cross-sectional view showing another modification of the optical element shown in FIG.
The optical element 10 shown in FIG. 8 has the same structure as the optical element 10 described with reference to FIG. 7 except that the optical element 10 further includes an adhesive layer 16 that covers the back surface of the substrate 11. This optical element 10 is suitable for an application to be used by being attached to an article. The adhesive layer 16 may be covered with release paper.

It is a top view which shows roughly the optical element of embodiment of this invention. It is sectional drawing along the II-II line of the optical element shown by FIG. It is a top view which shows an example of the image which an optical element displays. It is a figure which shows the example of the observation method of an optical element. It is a figure which shows an example of the image which can be observed with a left circularly-polarizing film. It is a figure which shows an example of the image which can be observed with a right circularly-polarizing film. It is sectional drawing which shows the modification of an optical element. It is sectional drawing which shows the other modification of an optical element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical element 11 ... Base material, 12 ... Colored layer, 13 ... Right polarized light reflecting layer, 14 ... Left polarized light reflecting layer, 15 ... Protective layer, 16 ... Adhesive layer, 20, 21, 22, 23, 24, 25 ... Viewing point, 50 ... Left circular polarizing filter, 60 ... Right circular polarizing filter, 101 ... Display unit, 102 ... Display unit.

Claims (8)

A substrate;
A right polarization reflecting layer that is formed on the substrate and reflects right-rotated polarized light out of the incident light;
A left polarization reflecting layer that is formed on the substrate and reflects left-rotated polarized light out of incident light;
The right polarization reflection layer and the left polarization reflection layer are provided with overlapping portions overlapping each other,
An optical element.   2. The optical element according to claim 1, wherein the right polarization reflection layer is made of a cholesteric liquid crystal material in which the rotation direction of the spiral structure is right-handed.   2. The optical element according to claim 1, wherein the left polarization reflection layer is made of a cholesteric liquid crystal material in which a helical structure rotates counterclockwise.   The colored layer is formed between the said base material and the said right polarization reflection layer, and between the said base material and the said left polarization reflection layer, The any one of Claims 1-3 characterized by the above-mentioned. The optical element described.   The optical element according to claim 1, wherein the right polarization reflection layer and the left polarization reflection layer are formed by halftone printing.   The optical element according to claim 1, further comprising a printed pattern layer formed on the right polarization reflection layer and the left polarization reflection layer. An optical element;
A right circularly polarizing filter that transmits clockwise circularly polarized light;
With a left circularly polarizing filter that transmits counterclockwise circularly polarized light,
The optical element is
A substrate;
A right polarization reflecting layer that is formed on the substrate and reflects right-rotated polarized light out of the incident light;
A left polarization reflecting layer that is formed on the substrate and reflects left-rotated polarized light out of incident light;
The right polarization reflection layer and the left polarization reflection layer are provided with overlapping portions overlapping each other,
An optical kit characterized by that. An optical element;
A printed matter on which the optical element is attached as a label,
The optical element is
A substrate;
A right polarization reflecting layer that is formed on the substrate and reflects right-rotated polarized light out of the incident light;
A left polarization reflecting layer that is formed on the substrate and reflects left-rotated polarized light out of incident light;
The right polarization reflection layer and the left polarization reflection layer are provided with overlapping portions overlapping each other,
A printed matter with a label characterized by that.

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