JP5423031B2 - Optical element - Google Patents

Optical element Download PDF

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JP5423031B2
JP5423031B2 JP2009032948A JP2009032948A JP5423031B2 JP 5423031 B2 JP5423031 B2 JP 5423031B2 JP 2009032948 A JP2009032948 A JP 2009032948A JP 2009032948 A JP2009032948 A JP 2009032948A JP 5423031 B2 JP5423031 B2 JP 5423031B2
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optical element
liquid crystal
light
polarizer
cholesteric liquid
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JP2010190988A (en
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智 牛腸
英樹 落合
章 久保
美保子 永吉
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凸版印刷株式会社
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Description

  The present invention relates to an optical technique that can be used for image display.

  Patent Document 1 describes an information recording medium in which a pattern constituting a character string is divided into two sub patterns, and these sub patterns are arranged apart from each other. Each of these sub-patterns cannot be identified as the previous character string or the characters contained in this character string. The previous character string is reproduced by cutting the information recording medium into a plurality of portions and arranging them so that the sub-patterns overlap. That is, these sub-patterns form a latent image that is visualized by overlapping.

  This information recording medium does not require a tool for visualizing the latent image. Therefore, this information recording medium has an advantage that anybody who knows the procedure can visualize the latent image. Further, it is possible to display different characters from the characters included in the previous character string in each sub-pattern. That is, a plurality of information can be recorded in the same area.

JP 2002-67558 A

  In the previous technique, the sub-pattern can be observed with the naked eye even before the latent image is visualized. Therefore, in order to display different character strings for the pattern to be reproduced and the sub-pattern, it is necessary to devise the shape of the pattern to be reproduced and the sub-pattern. Also, with this technology, it is difficult to achieve complex visual effects.

  An object of the present invention is to make it possible to realize a complicated visual effect and to reduce restrictions on the shape of a pattern to be recorded as a latent image.

According to the first aspect of the present invention, the first and second polarizers and the first and second polarizers include first and second regions having different slow axis directions or different refractive index anisotropies. A retardation layer, a second retardation layer including third and fourth regions having different slow axis directions or different refractive index anisotropies, and a cholesteric liquid crystal layer, The arrangement is such that the first state where the first and second polarizers do not face each other, the first and second polarizers face each other, and the cholesteric liquid crystal layer is interposed between the first and second polarizers. The first retardation layer is interposed between the first polarizer and the cholesteric liquid crystal layer, and the second retardation layer is interposed between the second polarizer and the cholesteric liquid crystal layer. an optical element capable of changing between the two states, the light By bending the element, the arrangement can be changed from the first state to the second state, and when the arrangement is changed from the first state to the second state in the optical element, It said first and second polarizer, said first and second retardation layer and the that have indicia is provided for aligning a portion of the cholesteric liquid crystal layer to a portion of another light optical element is provided Is done.

  According to the present invention, it is possible to realize a complicated visual effect and reduce restrictions on the shape of a pattern to be recorded as a latent image.

1 is a plan view schematically showing an optical element according to one embodiment of the present invention. Sectional drawing along the II-II line of the optical element shown in FIG. FIG. 3 is a plan view schematically showing one component of the optical element shown in FIGS. 1 and 2. FIG. 3 is a plan view schematically showing other components of the optical element shown in FIGS. 1 and 2. FIG. 3 is a diagram schematically showing an example of an image displayed by the optical element shown in FIGS. 1 and 2. The figure which shows schematically the other example of the image which the optical element shown in FIG.1 and FIG.2 displays. FIG. 6 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 5. FIG. 6 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 5. FIG. 6 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 5. FIG. 6 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 5. FIG. 7 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 6. FIG. 7 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 6. FIG. 7 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 6. FIG. 7 is a diagram showing the principle that an optical element displays an image under the conditions shown in FIG. 6. The top view which shows schematically the optical element which concerns on one modification. The top view which shows roughly the optical element which concerns on another modification. Furthermore, the top view which shows schematically the optical element which concerns on another modification. FIG. 18 is a diagram schematically showing an example of a method for visualizing a latent image recorded on the optical element shown in FIG. 17.

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

  FIG. 1 is a plan view schematically showing an optical element according to an aspect of the present invention. FIG. 2 is a sectional view taken along line II-II of the optical element shown in FIG. FIG. 3 is a plan view schematically showing one component of the optical element shown in FIGS. 1 and 2. FIG. 4 is a plan view schematically showing other components of the optical element shown in FIGS. 1 and 2.

  In FIG. 1, the front surface of the optical element 10 is depicted. 1 to 4, the X direction and the Y direction are parallel to the main surface of the optical element 10 and are orthogonal to each other. The Z direction is a direction perpendicular to the X direction and the Y direction.

  The optical element 10 shown in FIGS. 1 and 2 is an element that can be used for preventing forgery, for example. As shown in FIG. 2, the optical element 10 includes a support 11, coating layers 12a and 12b, polarizers 13a and 13b, retardation layers 14H and 14Q, and a cholesteric liquid crystal layer 15.

  The support 11 is a transparent light transmission layer, typically a colorless and transparent light transmission layer. The light transmission layer may be partially light-scattering or may be light-scattering as a whole.

  As this light transmission layer, for example, an unstretched film or sheet that can be produced by an extrusion method or a cast method, a stretched film or sheet, or a laminate comprising each of an unstretched film, an unstretched sheet, a stretched film, or a stretched sheet Can be used. The stretched film or sheet may be uniaxially stretched or biaxially stretched.

  Examples of the material for these films or sheets include cellophane, polycarbonate, polyethylene, polypropylene, polyolefin, ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyvinyl chloride, polyethylene naphthalate, polyethylene terephthalate, nylon, acrylic resin, or Triacetyl cellulose can be used.

  The support 11 may further include a light shielding layer in addition to the light transmission layer. For example, the support 11 may include a light shielding layer provided with one or more openings, and a light transmission layer at least partially disposed at the position of the previous opening. As a material for the light shielding layer, for example, paper, metal, or a resin containing a pigment can be used.

  The support 11 may not include the light transmission layer. That is, the support 11 may be a light shielding layer provided with one or more openings, for example.

  At least a part of the support 11 has flexibility. The support 11 can be bent so that one part thereof faces the other part. For example, the support 11 can be bent. The bent support 11 can typically be restored, but it may not be possible to restore it.

  The support 11 can be omitted. For example, when a part of a single polarizing film and another part are used as the polarizers 13a and 13b, the polarizing film can serve as the support 11.

  The covering layer 12 a covers one main surface of the support 11. The covering layer 12 b covers the other main surface of the support 11. One of the coating layers 12a and 12b may be omitted, or both may be omitted.

  An opening is provided in the coating layer 12a. An opening is provided in the covering layer 12b at a position corresponding to the opening of the covering layer 12a.

  Each of the covering layers 12a and 12b includes, for example, a concealing layer provided with an opening and a printed pattern formed thereon. One of the masking layer and the printing pattern may be omitted, or both may be omitted.

  The concealing layer suppresses light from entering the support 11 at a position other than the opening. In addition, the concealing layer prevents the printed pattern from being seen through the support 11.

  The masking layer is obtained using, for example, white or silver ink. The concealing layer can be formed by a printing method such as offset printing, screen printing, gravure printing, or flexographic printing.

  The print pattern is formed on the masking layer. The printed pattern is typically obtained using an ink of a different color than the hiding layer. The printing pattern can be formed by a printing method such as offset printing, screen printing, gravure printing, flexographic printing, letterpress printing, and intaglio printing.

  The polarizers 13a and 13b are disposed on one main surface of the support 11 and in the opening of the coating layer 12a. The polarizer 13b may be installed on the other main surface of the support 11 and in the opening of the coating layer 12b.

  Each of the polarizers 13a and 13b is an absorptive linear polarizer. As the absorption linear polarizer, for example, a film or sheet made of polyvinyl alcohol can be impregnated with iodine or a dichroic dye and subjected to a stretching treatment. Alternatively, an absorption type linear polarizer may be used in which a dichroic dye is aligned using an alignment film.

  A reflective linear polarizer may be used as one or both of the polarizers 13a and 13b. As the reflective linear polarizer, for example, a laminate of a cholesteric liquid crystal layer and a λ / 4 retardation layer can be used. Alternatively, as the reflective linear polarizer, a laminated body including a plurality of layers each having birefringence and arranged so that their slow axes are parallel may be used. Alternatively, a prism polarizer including a plurality of prisms arranged like a lenticular in a lenticular film may be used as the reflective linear polarizer. Alternatively, a birefringent diffractive polarizer in which a material having birefringence is arranged like a groove of a diffraction grating may be used as the reflective linear polarizer. Alternatively, a diffractive polarizer made of a diffraction grating having deep grooves may be used as the reflective linear polarizer.

  The polarizers 13a and 13b may not be linear polarizers. For example, one or both of the polarizers 13a and 13b may be elliptical polarizers. The elliptical polarizer can be obtained by combining, for example, a linear polarizer and a retardation layer.

  The transmission axis of the polarizer 13a forms an angle of 45 ° counterclockwise with respect to the Y direction when the optical element 10 is observed from the front. On the other hand, the transmission axis of the polarizer 13b forms an angle of 67.5 ° clockwise with respect to the Y direction when the optical element 10 is observed from the front. The angle formed by the transmission axis of the polarizer 13a with respect to the Y direction is arbitrary. The angle formed by the transmission axis of the polarizer 13b with respect to the transmission axis of the polarizer 13a is also arbitrary.

  The retardation layer 14H is installed on the polarizer 13a. As shown in FIG. 4, the retardation layer 14H includes a first region 14H1 and a second region 14H2.

  The region 14H2 constitutes a character string “SECURITY”. On the other hand, the region 14H1 constitutes the background of these character strings. The area 14H2 may constitute another character string. Alternatively, the region 14H2 may constitute a pattern other than the character string.

  Each of the regions 14H1 and 14H2 functions as a half-wave plate for light having the first wavelength λ1 in the visible light wavelength region. That is, each of the regions 14H1 and 14H2 has a fast axis and a slow axis that are each perpendicular to the Z direction and orthogonal to each other. Each of the regions 14H1 and 14H2 has a first wavelength λ1, and the electric field vector has a first linearly polarized light whose oscillation direction is parallel to the fast axis, the first wavelength λ1, and the electric field vector. When the second linearly polarized light whose vibration direction is parallel to the slow axis is incident in the same phase, the first linearly polarized light and the second linearly polarized light have a half phase difference of the first wavelength λ1 between them. To give a shot. The phase difference that each of the regions 14H1 and 14H2 gives between the first linearly polarized light and the second linearly polarized light may not be a half of the first wavelength λ1.

  Hereinafter, a plane including the propagation direction of linearly polarized light and the vibration direction of the electric field vector is referred to as a “polarization plane”. Further, hereinafter, in order to simplify the description, each of the regions 14H1 and 14H2 functions as a half-wave plate for light of all wavelengths in the visible light wavelength region.

  The slow axis of the first region 14H1 forms an angle of 22.5 ° clockwise with respect to the X direction when the optical element 10 is observed from the front. On the other hand, the slow axis of the second region 14H2 forms an angle of 22.5 ° counterclockwise with respect to the X direction when the optical element 10 is observed from the front.

  The angle formed by the slow axis of each of the regions 14H1 and 14H2 with respect to the X direction may not be 22.5 °. In addition, if the slow axis of the region 14H1 and the slow axis of the region 14H2 are not parallel to each other, the angle formed with respect to each other may not be 45 °.

  The regions 14H1 and 14H2 may have different refractive index anisotropy. That is, the phase difference that the region 14H1 gives between the first linearly polarized light and the second linearly polarized light may be different from the phase difference that the region 14H2 gives between the first linearly polarized light and the second linearly polarized light. In this case, the regions 14H1 and 14H2 may have different slow axis directions or the same.

  The retardation layer 14H includes, for example, an alignment film and a liquid crystal layer made of a liquid crystal material in which a mesogen is fixed. Such a retardation layer 14H can be obtained by forming an alignment film and a liquid crystal layer in this order.

The alignment film can be obtained, for example, by the following method.
First, a resin-containing solution is applied on the base. For example, polyvinyl alcohol or polyimide is used as the resin. For application of the solution, for example, a bar coating method, a gravure coating method, or a micro gravure coating method is used.

  After the coating film is dried, the position corresponding to the region 14H2 is masked, and the coating film is rubbed in this state. As the rubbing cloth, for example, cotton or velvet is used.

After removing the previous mask from the coating film, the position corresponding to the region 14H1 is masked, and in this state, the same rubbing treatment is applied to the coating film. However, in this rubbing process, the rubbing direction is different from the previous rubbing process. Here, rubbing is performed so that these rubbing directions form an angle of 45 °.
Thereafter, the mask is removed from the coating film. An alignment film is obtained as described above.

The alignment film can also be obtained by utilizing a photo-alignment technique as will be described below.
First, a photosensitive resin layer is formed on a base. This photosensitive resin layer is a layer that expresses the ability to align liquid crystal molecules in a direction parallel to the plane of polarization by irradiating linearly polarized light.

  Next, the first linearly polarized light is irradiated on the entire surface of the photosensitive resin layer. As the first linearly polarized light, for example, ultraviolet light having a wavelength of 365 nm is used.

Thereafter, the photosensitive resin layer is subjected to pattern exposure using, for example, a photomask, with the second linearly polarized light in which the direction of the intersecting line between the polarization plane and the main surface of the photosensitive resin layer is different from the first linearly polarized light. As the second linearly polarized light, for example, ultraviolet light having a wavelength of 365 nm is used. Further, in this pattern exposure, the line of intersection between the plane of polarization of the first linearly polarized light and the main surface of the photosensitive resin layer is the line of intersection of the plane of polarization of the second linearly polarized light and the main surface of the photosensitive resin layer. The angle is 45 °.
An alignment film is obtained as described above.

  The liquid crystal layer is obtained by, for example, fixing mesogens of a liquid crystal material such as a nematic liquid crystal material and a smectic liquid crystal material while maintaining their alignment state. This liquid crystal material is, for example, a thermotropic liquid crystal material. The liquid crystal layer is obtained, for example, by applying a liquid crystal material on the alignment film by a coating method such as a gravure printing method and solidifying the coating film. For example, a coating film made of a liquid crystal material exhibiting a nematic phase or a smectic phase is formed on the alignment film, and polymerization and / or crosslinking of the liquid crystal material is caused while maintaining the alignment state of the mesogen. Alternatively, it is made of a liquid crystal material and heated to a temperature equal to or higher than the glass transition temperature to form a coating film on which the liquid crystal material exhibits a nematic phase or a smectic phase, and the coating film is rapidly cooled below the glass transition temperature. .

  The retardation layer 14Q faces the retardation layer 14H with the cholesteric liquid crystal layer 15 interposed therebetween. As shown in FIG. 3, the retardation layer 14Q includes a third region 14Q1 and a fourth region 14Q2.

  The area 14Q2 constitutes the character string “SAFE”. On the other hand, the area 14Q1 constitutes the background of these character strings. The area 14Q2 may constitute another character string. Alternatively, the region 14Q2 may constitute a pattern other than the character string.

  Each of the regions 14Q1 and 14Q2 functions as a quarter-wave plate for light having the second wavelength λ2 in the visible light wavelength region. That is, each of the regions 14Q1 and 14Q2 has a fast axis and a slow axis that are each perpendicular to the Z direction and orthogonal to each other. Each of the regions 14Q1 and 14Q2 has the second wavelength λ2, and the electric field vector has the third linearly polarized light whose oscillation direction is parallel to the fast axis, the second wavelength λ2, and the electric field vector. When the fourth linearly polarized light whose oscillation direction is parallel to the slow axis is incident in the same phase, the third linearly polarized light and the fourth linearly polarized light are separated by a quarter of the second wavelength λ2. Inject with a phase difference. Hereinafter, in order to simplify the description, each of the regions 14Q1 and 14Q2 functions as a quarter-wave plate for light of all wavelengths in the visible light wavelength region.

  The phase difference that each of the regions 14Q1 and 14Q2 gives between the third linearly polarized light and the fourth linearly polarized light may not be a quarter of the second wavelength λ2. That is, the second wavelength λ2 may be the same as or different from the first wavelength λ1. The phase difference that each of the regions 14Q1 and 14Q2 gives between the third linearly polarized light and the fourth linearly polarized light is the phase difference that each of the regions 14H1 and 14H2 gives between the first linearly polarized light and the second linearly polarized light. May be the same or different.

  The slow axis of the third region 14Q1 is parallel to the X direction. On the other hand, the slow axis of the fourth region 14Q2 is parallel to the Y direction.

  The slow axis of each of the regions 14Q1 and 14Q2 may not be parallel to the X direction or the Y direction. Further, the slow axis of the region 14Q1 and the slow axis of the region 14Q2 do not have to be perpendicular to each other as long as they are not parallel to each other.

  The regions 14Q1 and 14Q2 may have different refractive index anisotropy. That is, the phase difference that the region 14Q1 gives between the third linearly polarized light and the fourth linearly polarized light may be different from the phase difference that the region 14Q2 gives between the third linearly polarized light and the fourth linearly polarized light. In this case, the regions 14Q1 and 14Q2 may have different slow axis directions or the same.

  The retardation layer 14Q can be obtained, for example, by the same method as described for the retardation layer 14H. Note that the retardation of each of the regions included in the retardation layers 14H and 14Q is changed by changing at least one of the thickness of the region, the type of the liquid crystal material, and the degree of alignment order. Therefore, a desired retardation can be achieved by optimizing them. Typically, the retardation layer 14Q is thinner than the retardation layer 14H.

  The cholesteric liquid crystal layer 15 is interposed between the retardation layers 14H and 14Q. The cholesteric liquid crystal layer 15 may be patterned or may not be patterned.

  When the cholesteric liquid crystal layer 15 is illuminated with white light as natural light from the normal direction, the reflectance of the right circularly polarized light having the third wavelength λ3 is the left circle having the third wavelength λ3. Greater than the reflectivity for polarized light and the reflectivity for right and left circularly polarized light having wavelengths other than the third wavelength λ3. That is, the cholesteric liquid crystal layer 15 causes selective reflection with respect to right circularly polarized light having the third wavelength λ3. The cholesteric liquid crystal layer 15 may cause selective reflection of left circularly polarized light having the third wavelength λ3 instead of selective reflection of right circularly polarized light having the third wavelength λ3.

  The third wavelength λ3 is, for example, substantially equal to the second wavelength λ2, and typically equal to the second wavelength λ2. In the following description, for the sake of simplicity, it is assumed that the third wavelength λ3 is equal to the second wavelength λ2.

  The cholesteric liquid crystal layer 15 is obtained, for example, by forming a coating film made of a cholesteric liquid crystal material on a base and immobilizing them while maintaining the alignment state of mesogens. For example, a coating film made of a cholesteric liquid crystal material is formed on a base, and polymerization and / or cross-linking of the liquid crystal material is caused while maintaining the mesogen alignment state. Alternatively, it is made of a liquid crystal material and heated to a temperature equal to or higher than the glass transition temperature, and a coating film in which the liquid crystal material exhibits a cholesteric phase is formed on the base, and the coating film is rapidly cooled below the glass transition temperature. Alternatively, a coating film containing a cholesteric liquid crystal material and a solvent is formed on the base, and the solvent is removed from the coating film while maintaining the orientation state of the mesogen.

  Examples of the cholesteric liquid crystal material include a liquid crystal compound that does not have a reflex axis, a liquid crystal composition that includes a liquid crystal compound that does not have a replay axis, or a liquid crystal compound that has a reflex axis and a liquid crystal compound. A liquid crystal composition containing a compound having no image axis, that is, a chiral agent can be used.

  As the liquid crystal compound, a side chain polymer liquid crystal compound or a main chain polymer liquid crystal compound can be used.

  As the side chain type polymer liquid crystal compound, for example, a polyacrylate, polymethacrylate, polymalonate, or polysiloxane that exhibits liquid crystallinity can be used.

  As the main chain type polymer liquid crystal compound, for example, an acylated product of hydroxyalkyl cellulose, a polypeptide, an aromatic polyester, a polycarbonate, an aromatic polyester imide, or an aromatic polyamide that exhibits liquid crystallinity can be used. .

  Hydroxyalkyl cellulose is, for example, hydroxypropyl cellulose or hydroxybutylated hydroxypropyl cellulose. The acyl group is, for example, one in which the functional group bonded to the carbon atom of the carbonyl group is an aliphatic, alicyclic or aromatic hydrocarbon group having 1 to 30 carbon atoms.

  Examples of the acylated product of hydroxyalkyl cellulose include, for example, ester of hydroxyalkyl cellulose with saturated carboxylic acid, ester of hydroxyalkyl cellulose with alicyclic carboxylic acid, ester of hydroxyalkyl cellulose with aromatic carboxylic acid, or hydroxy Esters of alkyl cellulose with unsaturated carboxylic acids can be used.

  Examples of the saturated carboxylic acid include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, 2-methylbutyric acid, trimethylacetic acid, caproic acid, heptanoic acid, caprylic acid, nonanoic acid, capric acid, lauric acid Palmitic acid, stearic acid, or isostearic acid can be used. As the alicyclic carboxylic acid, for example, cyclohexane carboxylic acid, cyclohexyl acetic acid, cyclohexane propionic acid, or cyclohexane butyric acid can be used. As the aromatic carboxylic acid, for example, benzoic acid, phenylacetic acid, 3-phenylpropionic acid, 5-phenylvaleric acid, or 4-phenylbutyric acid can be used. As the unsaturated carboxylic acid, for example, acrylic acid, methacrylic acid, crotonic acid, maleic acid, or itaconic acid can be used.

  For example, as an ester of hydroxyalkyl cellulose with carboxylic acid, ester of hydroxypropyl cellulose with acetic acid, ester of hydroxypropyl cellulose with propionic acid, ester of hydroxybutylated hydroxypropyl cellulose with acetic acid, hydroxybutylated hydroxypropyl cellulose Ester of propionic acid, ester of hydroxybutyl cellulose with acetic acid, ester of hydroxybutyl cellulose with propionic acid, ester of hydroxypropyl cellulose with acrylic acid, ester of hydroxypropyl cellulose with methacrylic acid, hydroxybutylated hydroxy Ester of propylcellulose with acrylic acid, ester of hydroxybutylated hydroxypropylcellulose with methacrylic acid Ester of hydroxybutyl cellulose with acrylic acid, ester of hydroxybutyl cellulose with methacrylic acid, ester of hydroxypropyl cellulose with propionic acid and methacrylic acid, ester of hydroxybutylated hydroxypropyl cellulose with propionic acid and methacrylic acid, or Esters of hydroxybutyl cellulose with propionic acid and methacrylic acid can be used.

  The ester of hydroxyalkyl cellulose with carboxylic acid may be a completely esterified product or a partially esterified product.

  In addition, when an ester of hydroxyalkyl cellulose and unsaturated carboxylic acid is mixed with an initiator and a polymerizable compound, which will be described later, polymerization and / or cross-linking occurs by irradiating energy rays such as ultraviolet rays and electron beams. obtain. That is, in this case, mesogens can be immobilized by energy beam irradiation.

  For immobilization of mesogens by irradiation with energy rays, it is not necessary that all carboxylic acids are unsaturated carboxylic acids. For example, in an ester of a hydroxyalkyl cellulose and a saturated carboxylic acid, mesogens can be immobilized by irradiation with energy rays even when 0.1 to 20% of the saturated carboxylic acid is substituted with an unsaturated carboxylic acid. There is.

  The cholesteric liquid crystal material may contain a low molecular liquid crystal compound instead of the high molecular liquid crystal compound. Alternatively, the cholesteric liquid crystal material may further contain a low molecular liquid crystal compound in addition to the high molecular liquid crystal compound.

  As the polymerizable compound, for example, a radical polymerizable compound can be used. As a radically polymerizable compound, for example, a polyfunctional monomer, a polyfunctional oligomer, a monofunctional monomer, or a mixture containing two or more thereof can be used.

  Examples of the polyfunctional monomer include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,6-hexanediol acrylate, 1,6-hexanediol methacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate. Rate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexaacrylate, or dipentaerythritol hexamethacrylate can be used.

  As the polyfunctional oligomer, for example, polyurethane polyacrylate, polyurethane polymethacrylate, polyether polyacrylate, polyether polymethacrylate, epoxy resin polyacrylate, epoxy resin polymethacrylate, acrylic polyol polyacrylate, or acrylic polyol polymethacrylate is used. be able to.

  Examples of the monofunctional monomer include alkyl acrylate or alkyl methacrylate having an alkyl group having 1 to 18 carbon atoms, benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, and alkylene groups having 2 carbon atoms. Alkylene glycol acrylate or alkylene glycol methacrylate in the range of 1 to 4, alkoxyalkyl acrylate in which the alkoxy group has 1 to 10 carbon atoms and the alkyl group has 2 to 4 carbon atoms, or Alkoxyalkyl methacrylate, polyalkylene glycol acrylate or polyalkylene glycol methacrylate in which the alkylene group has 2 to 4 carbon atoms, Can use alkoxy polyalkylene glycol acrylate or alkoxy polyalkylene glycol methacrylate in which the number of carbon atoms of the alkoxy group is in the range of 1 to 10 and the number of carbon atoms of the alkylene group is in the range of 2 to 4 .

  A cationic polymerizable compound may be used as the polymerizable compound. As the cationic polymerizable compound, for example, a cationic polymerizable monomer such as an aromatic epoxy compound, an alicyclic epoxy compound, and a glycidyl ester compound can be used.

  As the initiator, for example, a radical polymerization initiator or a cationic polymerization initiator can be used.

  As the radical polymerization initiator, for example, an acetophenone initiator, a benzoin ether initiator, a benzyl ketal initiator, an α-dicarbonyl initiator, or an α-acyloxime ester initiator can be used. For example, α-hydroxyacetophenone, α-aminoacetophenone, acetophenone diethyl ketal, benzyl dimethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylphenylpropanone, benzophenone, 4,4′-bis (dimethylamino) Benzophenone, isopropylthioxanthone, or a combination of benzophenone and N-methyldiethanolamine can be used.

  As the cationic polymerization initiator, for example, a compound known as a cationic polymerization initiator can be used alone. As the cationic polymerization initiator, a combination of a compound known as a cationic polymerization initiator and a sensitizer and / or a peroxide may be used. For example, allyl iodonium salt-α-hydroxyacetophenone initiator, triallylsulfonium salt initiator, metallocene compound-peroxide initiator, metallocene compound-thioxanthone initiator, or metallocene compound-anthracene initiator is used. can do.

  When the cholesteric liquid crystal layer 15 is formed using a composition containing a liquid crystal material and a polymerizable compound, for example, 40 to 98 parts by mass of a liquid crystal material, 2 to 60 parts by mass of a polymerizable compound, and 0 to 10 are used. Mix with parts by weight of initiator. Typically, 55 to 95 parts by mass of a liquid crystal material, 5 to 45 parts by mass of a polymerizable compound, and 0 to 5 parts by mass of an initiator are mixed. This composition may further contain a solvent and / or an additive as necessary.

  This optical element 10 includes an arrangement of the polarizers 13a and 13b, the retardation layers 14H and 14Q, and the cholesteric liquid crystal layer 15, the first state where the polarizers 13a and 13b do not face each other, and the polarizers 13a and 13b that face each other. The cholesteric liquid crystal layer 15 is interposed between the polarizers 13a and 13b, the retardation layer 14H is interposed between the polarizer 13a and the cholesteric liquid crystal layer 15, and the retardation layer 14Q is disposed between the polarizer 13b and the cholesteric liquid crystal layer 5. It is possible to change between the second state interposed between the two. For example, by bending the optical element 10, the previous arrangement can be changed from the first state to the second state. The optical element 10 displays different images depending on whether the previous arrangement is in the first state or the second state, as will be described below.

  First, an image displayed by the optical element 10 when the previous arrangement is in the first state, that is, when the optical element 10 is not deformed as shown in FIGS. 1 and 2 will be described.

  When the front surface of the optical element 10 is illuminated with white light as natural light, right circularly polarized light having a wavelength λ3 and right circularly polarized light having substantially the same wavelength among the light transmitted through the retardation layer 14Q. Are reflected by the cholesteric liquid crystal layer 15, and other light components are transmitted through the cholesteric liquid crystal layer 15. Therefore, to the observer who is observing the optical element 10 from the front, the portion of the optical element 10 corresponding to the retardation layer 14Q looks almost the same color as the light having the wavelength λ3. Hereinafter, the image displayed by the previous portion in this state is referred to as a “first image”.

  When the back surface of the optical element 10 is illuminated with white light as natural light, a part of the light incident on the polarizer 13a is absorbed by the polarizer 13a. Of the light transmitted through the polarizer 13a, right-handed circularly polarized light having a wavelength λ3 and right-handed circularly polarized light having substantially the same wavelength are reflected by the cholesteric liquid crystal layer 15, and other light components are cholesteric liquid crystal. It penetrates through layer 15. That is, the cholesteric liquid crystal layer 15 reflects only a part of the incident light and transmits the remaining light components. Therefore, to the observer who is observing the optical element 10 from the front, the portion corresponding to the retardation layer 14Q of the optical element 10 looks almost the same white color as the illumination light except that it is darker than the illumination light. . Hereinafter, the image displayed by the previous portion in this state is referred to as a “second image”.

  When the front surface of the optical element 10 is illuminated with white light as natural light and the optical element 10 is observed from behind, the portion of the optical element 10 corresponding to the retardation layer 14Q is darker than the illumination light. Appears almost the same white color as the illumination light. Hereinafter, an image displayed by the previous portion in this state is referred to as a “third image”. The color of this third image is equal to the color of the second image.

  Further, when the back surface of the optical element 10 is illuminated with white light as natural light and the optical element 10 is observed from behind, the portion of the optical element 10 corresponding to the retardation layer 14Q has a wavelength λ3. It looks almost the same color as light. Hereinafter, an image displayed by the previous portion in this state is referred to as a “fourth image”. This fourth image is darker than the first image.

  Next, an image displayed by the optical element 10 when the previous arrangement is in the second state will be described with reference to FIGS. 5 and 6.

  FIG. 5 is a diagram schematically illustrating an example of an image displayed by the optical element illustrated in FIGS. 1 and 2. FIG. 6 is a diagram schematically illustrating another example of an image displayed by the optical element illustrated in FIGS. 1 and 2.

  5 and 6 show a state where the optical element 10 is bent so that the front surface thereof is concave. Specifically, the optical element 10 is bent so that the polarizers 13a and 13b face each other with the retardation layers 14H and 14Q and the cholesteric liquid crystal layer 15 therebetween. Further, the transmission axes of the polarizers 13a and 13b are parallel to each other in FIG. 5 and form an angle of 45 ° with respect to each other in FIG.

  First, an image displayed by the optical element 10 when the optical element 10 is bent as shown in FIG. 5 and white light as natural light is emitted from the light source 20 toward the polarizer 13b will be described. Here, the light source 20 is disposed so as to face the polarizer 13a with the polarizer 13b interposed therebetween.

  In this case, for the observer who is observing the portion corresponding to the polarizer 13b of the optical element 10 from the light source 20 side, the background of the color substantially the same as the light having the wavelength λ3 and the black character string “ SAFE "is visible. Hereinafter, an image displayed by the previous portion in this state is referred to as a “fifth image”.

  In this case, for the observer who is observing the optical element 10 from the side opposite to the light source 20, the portion of the optical element 10 corresponding to the polarizer 13b is darker than the illumination light. Appears almost the same white color as the illumination light. Hereinafter, an image displayed by the previous portion in this state is referred to as a “sixth image”. This sixth image is darker than the second and third images.

  Next, an image displayed by the optical element 10 when the optical element 10 is bent and white light as natural light is emitted from the light source 20 toward the polarizer 13a as shown in FIG. 6 will be described. Here, the light source 20 is disposed so as to face the polarizer 13b with the polarizer 13a interposed therebetween.

  In this case, for the observer who is observing the portion corresponding to the polarizer 13b in the optical element 10 from the side opposite to the light source 20 with respect to the optical element 10, the illumination light except for being darker than the illumination light And a black character string “SECURITY” can be seen. Hereinafter, the image displayed by the previous portion in this state is referred to as a “seventh image”.

  In this case, for an observer observing the optical element 10 from the light source 20 side, the portion of the optical element 10 corresponding to the polarizer 13b is substantially the same color as the light having the wavelength λ3. Looks like. Hereinafter, an image displayed by the previous portion in this state is referred to as an “eighth image”. The eighth image has the same brightness as the fourth image.

  The principle that the optical element 10 displays the above-described image when the previous arrangement is in the second state will be described with reference to FIGS.

  FIG. 7 to FIG. 10 are diagrams showing the principle that an optical element displays an image under the conditions shown in FIG. FIG. 11 to FIG. 14 are diagrams showing the principle that an optical element displays an image under the conditions shown in FIG.

  When white light as natural light is emitted from the light source 20 toward the polarizer 13b of the optical element 10 bent as shown in FIG. 5, the polarization plane of the polarizer 13b is transmitted through the polarizer 13b as shown in FIGS. Transmits linearly polarized light parallel to the axis.

  Of the linearly polarized light, the light incident on the region 14Q1 of the retardation layer 14Q is converted into right circularly polarized light as shown in FIGS. On the other hand, the linearly polarized light that has entered the region 14Q2 of the retardation layer 14Q is converted into left circularly polarized light as shown in FIGS.

  The cholesteric liquid crystal layer 15 selectively reflects the right circularly polarized light component having the wavelength λ3 out of the circularly polarized light and transmits the remaining light component. That is, as shown in FIGS. 7 and 8, the portion of the cholesteric liquid crystal layer 15 corresponding to the region 14Q1 selectively reflects part of the incident light and transmits the rest. On the other hand, as shown in FIGS. 9 and 10, a portion of the cholesteric liquid crystal layer 15 corresponding to the region 14Q2 transmits all incident light.

  The right circularly polarized light selectively reflected by the cholesteric liquid crystal layer 15 is incident on the region 14Q1 of the retardation layer 14Q, as shown in FIGS. The region 14Q1 converts right circularly polarized light having the wavelength λ3 into linearly polarized light whose polarization plane is parallel to the transmission axis of the polarizer 13b, and emits the linearly polarized light toward the polarizer 13b.

  Therefore, when the white light as natural light is emitted from the light source 20 toward the polarizer 13b of the optical element 10 bent as shown in FIG. 5 and observed from the light source 20 side, the region 14Q1 of the optical element 10 is irradiated to the region 14Q1. The corresponding part appears to be approximately the same color as the light having wavelength λ3. In this case, as described above, the portion corresponding to the region 14Q2 in the cholesteric liquid crystal layer 15 transmits all of the incident light, so that the portion corresponding to the region 14Q2 in the optical element 10 appears black.

  As described with reference to FIG. 3, the region 14Q2 forms the character string “SAFE”, and the region 14Q1 forms the background of the character string “SAFE”. Therefore, in this case, the observer 30 sees a background having a color almost equal to the light having the wavelength λ3 and the black character string “SAFE”.

  Further, the circularly polarized light transmitted through the cholesteric liquid crystal layer 15 is incident on the retardation layer 14H as shown in FIGS. Each of the regions 14H1 and H2 of the retardation layer 14H converts this circularly polarized light into circularly polarized light whose electric field vector has a rotation direction opposite to that of the circularly polarized light, and emits the circularly polarized light toward the polarizer 13a.

  As described above, the portion of the cholesteric liquid crystal layer 15 corresponding to the region 14Q1 selectively reflects the right circularly polarized light having the wavelength λ3, and the portion corresponding to the region 14Q2 transmits all the incident light. Therefore, the spectrum of the circularly polarized light transmitted through the portion corresponding to the region 14Q1 in the cholesteric liquid crystal layer 15 is different from the spectrum of the circularly polarized light transmitted through the portion corresponding to the region 14Q2 in the cholesteric liquid crystal layer 15.

  However, the wavelength range of light selectively reflected by the cholesteric liquid crystal layer 15 is much narrower than the wavelength range of incident light. In addition, the cholesteric liquid crystal layer 15 selectively reflects only a part of light whose wavelength is substantially equal to the wavelength λ3. Therefore, the circularly polarized spectrum transmitted through the portion corresponding to the region 14Q1 in the cholesteric liquid crystal layer 15 and the circularly polarized spectrum transmitted through the portion corresponding to the region 14Q2 in the cholesteric liquid crystal layer 15 are colored with the naked eye. There is no difference that can be identified as a difference.

  Of the circularly polarized light incident thereon, the polarizer 13a absorbs a linearly polarized component whose polarization plane is perpendicular to the transmission axis of the polarizer 13a, and transmits a linearly polarized component whose polarization plane is parallel to the transmission axis of the polarizer 13a. Let As is clear from the above description, the spectrum of the light incident on the polarizer 13a is almost equal to the spectrum of the light from the light source 20 transmitted through the polarizer 13b at any position on the polarizer 13a.

  Therefore, when white light as natural light is emitted from the light source 20 toward the polarizer 13b of the optical element 10 bent as shown in FIG. 5 and observed from the side opposite to the light source 20 with respect to the optical element 10. The portion of the optical element 10 corresponding to the polarizer 13b looks almost the same white as the illumination light except that it is darker than the illumination light.

  When white light as natural light is emitted from the light source 20 toward the polarizer 13a of the optical element 10 bent as shown in FIG. 6, the polarization plane of the polarizer 13a is transmitted through the polarizer 13a as shown in FIGS. Transmits linearly polarized light parallel to the axis.

  Among the linearly polarized light, the light incident on the region 14H1 of the retardation layer 14H has a polarization plane clockwise with respect to the transmission axis of the polarizer 13a when viewed from the light source 20, as shown in FIGS. To linearly polarized light having an angle of 45 °. Of the linearly polarized light, the light incident on the region 14H2 of the retardation layer 14H has a plane of polarization with respect to the transmission axis of the polarizer 13a when viewed from the light source 20 side, as shown in FIGS. It is converted to linearly polarized light having an angle of 45 ° counterclockwise.

  The cholesteric liquid crystal layer 15 selectively reflects the right circularly polarized light component having the wavelength λ3 among these linearly polarized light and transmits the remaining light component. As is clear from the above description, when the light incident on the cholesteric liquid crystal layer 15 is white light as linearly polarized light, the color of the light transmitted through the cholesteric liquid crystal layer 15 and the incident light due to selective reflection. Is not so different from the color of the eye that it can be discerned with the naked eye. That is, selective reflection by the cholesteric liquid crystal layer 15 can be ignored.

The linearly polarized light transmitted through the cholesteric liquid crystal layer 15 is incident on the retardation layer 14Q.
The polarization plane of linearly polarized light transmitted through the portion corresponding to the region 14H1 in the cholesteric liquid crystal layer 15 is parallel to the slow axis of the region 14Q1 as shown in FIG. 11, and as shown in FIG. It is perpendicular to the slow axis. Therefore, the linearly polarized light is transmitted through the retardation layer 14Q without being changed in the polarization state.

  The plane of polarization of linearly polarized light transmitted through the portion corresponding to the region 14H2 in the cholesteric liquid crystal layer 15 is perpendicular to the slow axis of the region 14Q1 as shown in FIG. 12, and as shown in FIG. Parallel to the slow axis. Accordingly, this linearly polarized light is also transmitted through the retardation layer 14Q without being changed in the polarization state.

The linearly polarized light transmitted through the retardation layer 14Q is incident on the polarizer 13b.
As shown in FIGS. 11 and 13, the plane of polarization of the linearly polarized light incident on the polarizer 13b at a position corresponding to the region 14H1 is parallel to the transmission axis of the polarizer 13b. Therefore, this linearly polarized light is transmitted through the polarizer 13b. Therefore, to the observer 30, the part corresponding to the region 14H1 in the optical element 10 appears almost the same white color as the illumination light except that it is darker than the illumination light.

  On the other hand, as shown in FIGS. 12 and 14, the plane of polarization of the linearly polarized light incident on the polarizer 13b at a position corresponding to the region 14H2 is perpendicular to the transmission axis of the polarizer 13b. Therefore, this linearly polarized light is absorbed by the polarizer 13b. Therefore, to the observer 30, the portion corresponding to the region 14H2 in the optical element 10 appears black.

  As described with reference to FIG. 4, the region 14H2 constitutes the character string “SECURITY”, and the region 14H1 constitutes the background of the character string “SECURITY”. Therefore, in this case, the observer 30 sees a white background that is substantially the same as the illumination light except that it is darker than the illumination light, and a black character string “SECURITY”.

  Further, the right circularly polarized light reflected by the cholesteric liquid crystal layer 15 is incident on the retardation layer 14H. Each of the regions 14H1 and H2 of the retardation layer 14H converts the right circularly polarized light into left circularly polarized light, and emits it toward the polarizer 13a. The polarizer 13a absorbs the linearly polarized light component of the right-handed circularly polarized light incident thereon, the polarization plane of which is perpendicular to the transmission axis of the polarizer 13a, and the polarization plane of which is parallel to the transmission axis of the polarizer 13a. Make it transparent.

  Accordingly, when the white light as natural light is emitted from the light source 20 toward the polarizer 13a of the optical element 10 bent as shown in FIG. 6 and observed from the light source 20 side, the polarizer 13b of the optical element 10 is observed. The portion corresponding to 見 え る appears to be almost the same color as the light having wavelength λ3.

  As described above, in this optical element 10, the first latent image is formed by providing the regions 14Q1 and 14Q2 in the retardation layer 14Q, and the second latent image is formed by providing the regions 14H1 and 14H2 in the retardation layer 14H. doing. As described with reference to FIGS. 5 and 7 to 10, the first latent image is obtained by bending the optical element 10 as shown in FIG. 5 and observing reflected light under a predetermined illumination condition. Visualize as a fifth image. On the other hand, in the second latent image, as described with reference to FIGS. 6 and 1 to 14, the optical element 10 is bent as shown in FIG. 6, and the transmitted light is observed under a predetermined illumination condition. This is visualized as a seventh image. These fifth and seventh images are displayed in the same area. That is, the optical element 10 achieves a complicated visual effect.

  Further, the pattern constituting the first latent image and the pattern constituting the second latent image can be determined independently of each other. That is, the optical element 10 has few restrictions on the shape of the pattern to be recorded as a latent image.

The optical element 10 can be variously modified.
FIG. 15 is a plan view schematically showing an optical element according to a modification. The optical element 10 is the same as the optical element 10 described with reference to FIGS. 1 to 14 except that the optical element 10 further includes marks 17a and 17b.

  The marks 17a and 17b are print patterns. The marks 17a and 17b may have a convex structure or a concave structure formed by, for example, embossing. Alternatively, the marks 17a and 17b may be one or more through holes or notches.

  The mark 17a can be used for alignment when the optical element 10 is bent as shown in FIG. On the other hand, the mark 17b can be used for alignment when the optical element 10 is bent as shown in FIG.

  Providing the marks 17a and 17b makes it easy to observe each of the fifth image and the seventh image under optimum conditions.

  FIG. 16 is a plan view schematically showing an optical element according to another modification. This optical element 10 is the same as the optical element 10 described with reference to FIGS. 1 to 14 except that the retardation layer 14Q is provided not on the cholesteric liquid crystal layer 15 but on the polarizer 13b. is there. In this case, the same effect as described above can be obtained.

  Instead of disposing the cholesteric liquid crystal layer 15 and the retardation layer 14Q on the polarizer 13a, the retardation layer 14Q and the cholesteric liquid crystal layer 15 may be disposed on the polarizer 13b in this order. Alternatively, instead of arranging the retardation layer 14H, the cholesteric liquid crystal layer 15 and the retardation layer 14Q on the polarizer 13a, the retardation layer 14Q, the cholesteric liquid crystal layer 15 and the retardation layer 14H are arranged in this order on the polarizer 13b. May be. Even when the arrangement is changed in this way, the same effect as described above can be obtained.

  The polarizers 13a and 13b, the retardation layers 14H and 14Q, and the cholesteric liquid crystal layer 15 may be distributed at three or more positions instead of being distributed at two positions. For example, instead of disposing the cholesteric liquid crystal layer 15 and the retardation layer 14Q on the polarizer 13a, an opening is further provided in the coating layers 12a and 12b at a position between the polarizers 13a and 13b, The cholesteric liquid crystal layer 15 may be installed at the position of the added opening, and the retardation layer 14Q may be installed so as to face the polarizer 13b with the support 11 interposed therebetween. When such a structure is adopted, the optical element 10 is folded in a Z shape so that the polarizers 13a and 13b face each other, the cholesteric liquid crystal layer 15 is interposed between the polarizers 13a and 13b, and the retardation layer 14H Can be interposed between the polarizer 13a and the cholesteric liquid crystal layer 15, and the retardation layer 14Q can be interposed between the polarizer 13b and the cholesteric liquid crystal layer 15.

  FIG. 17 is a plan view schematically showing an optical element according to still another modification.

  The optical element 10 is the same as the optical element 10 described with reference to FIG. 15 except that a perforation 19 is provided. The optical element 10 can be separated along the perforation 19 into the first portion 10a and the second portion 10b.

  Instead of providing the perforation 19, a mark for cutting the optical element 10 may be provided. For example, as this mark, a convex structure or a concave structure formed by a printing pattern, embossing, or the like, one or more through holes or notches may be formed.

  FIG. 18 is a diagram schematically showing an example of a method for visualizing a latent image recorded on the optical element shown in FIG.

  In FIG. 18, the optical element 10 shown in FIG. 17 is cut along the perforation 19 into the first portion 10a and the second portion 10b, the front surfaces of the first portion 10a and the second portion 10b face each other, and the second portion 10b is drawn so that its outline is located on the mark 17a. Thus, when the optical element 10 is separated into the first portion 10a and the second portion 10b, it is easy to face the polarizers 13a and 13b with the retardation layers 14H and 14Q and the cholesteric liquid crystal layer 15 in between. It is.

  When the optical element 10 is separated into the first portion 10a and the second portion 10b, the optical element 10 may not be deformable.

  The first portion 10a and the second portion 10b may be separated from each other in advance. For example, the first part 10a and the second part 10b may be an optical kit including them as first and second optical elements.

  The above-described technique can be applied to uses other than forgery prevention. In other words, the above technique can be applied to image display that is not intended to prevent forgery. For example, the optical element 10 and the optical kit can be used as, for example, a toy, a learning material, or a decoration.

The optical element 10 and the optical kit can take various forms.
For example, the optical element 10 may have any form as long as all components are integrated, such as securities, certificates, and bills.

In addition, the optical kit may be configured by only a plurality of optical elements that are integrated with each other and separated from each other. Alternatively, the optical kit may further include connectors such as strings and chains that connect the optical elements to each other. For example, a through-hole is provided in each of the polarizer 13b, the polarizer 13a, the retardation layer 14H, the cholesteric liquid crystal layer 15, the retardation layer 14Q, and the polarizer 13b, and the ring on one end side of the chain passes through the previous laminate. The ring on the other end side may be passed through the through hole of the polarizer 13b.
Hereinafter, another aspect of the present invention will be described.
[1] A first retardation layer including first and second polarizers, a first retardation layer including first and second regions having different slow axis directions or different refractive index anisotropies, A second retardation layer including third and fourth regions having different phase axis directions or different refractive index anisotropies, and a cholesteric liquid crystal layer, and the arrangement thereof is The first state where the first and second polarizers do not face each other, the first and second polarizers face each other, the cholesteric liquid crystal layer is interposed between the first and second polarizers, and the first position Between the second state in which a phase difference layer is interposed between the first polarizer and the cholesteric liquid crystal layer, and the second phase difference layer is interposed between the second polarizer and the cholesteric liquid crystal layer. Changeable optical element.
[2] The arrangement can be changed from the first state to the second state by bending the optical element, and the optical element can be changed from the first state to the second state. When changing, a mark is provided for aligning part of the first and second polarizers, the first and second retardation layers, and the cholesteric liquid crystal layer with respect to the other part. Item 2. The optical element according to Item 1.
[3] The optical element according to item 1, wherein the arrangement can be changed from the first state to the second state by cutting the optical element into a plurality of parts and superimposing the plurality of parts. .
[4] The optical element according to item 3, wherein the optical element is provided with marks and / or perforations for cutting the optical element into the plurality of portions.
[5] In the optical element, when the plurality of portions are overlapped, a part of the first and second polarizers, the first and second retardation layers, and the cholesteric liquid crystal layer are replaced with another part. Item 5. The optical element according to Item 3 or 4, wherein a mark for alignment is provided.
[6] Each of the first and second polarizers is a linear polarizer, and the first and second regions are a half wavelength with respect to light having a first wavelength in the visible light wavelength region. Each of the third and fourth regions functions as a quarter-wave plate with respect to light having a second wavelength in the visible light wavelength region. Item 6. The optical element according to any one of Items 1 to 5, wherein the functions of the slow axis are different from each other.
[7] When the optical element in which the arrangement is in the second state is irradiated with light having the first wavelength from the first polarizer side, the first and second regions are respectively In the optical element in which the first and second linearly polarized light whose polarization planes are orthogonal to each other are emitted toward the second retardation layer and the arrangement is in the second state, each of the third and fourth regions is slow. Item 7. The optical element according to Item 6, wherein the phase axis is parallel or perpendicular to the plane of polarization of the first linearly polarized light.
[8] As the second state, it is possible to form two or more states in which the directions of the transmission axes of the second polarizer are different from each other with respect to the slow axes of the third and fourth regions. Item 8. The optical element according to Item 7.
[9] Including a plurality of optical elements separated from each other, the first and second polarizers face each other by overlapping the plurality of optical elements, and a cholesteric liquid crystal layer is interposed between the first and second polarizers. The first retardation layer including the first and second regions which are interposed and have different slow axis directions or different refractive index anisotropies are the first polarizer and the cholesteric liquid crystal layer. Between the second polarizer and the cholesteric layer. The second retardation layer includes third and fourth regions that are interposed between each other and have different slow axis directions or different refractive index anisotropies. An optical kit capable of forming a structure interposed between the liquid crystal layer.
[10] The first and second polarizers, the first and second retardation layers when the structure is formed by superimposing the plurality of optical elements on at least a part of the plurality of optical elements. Item 10. The optical element according to Item 9, wherein a mark for aligning a part of the cholesteric liquid crystal layer with another part is provided.
[11] Each of the first and second polarizers is a linear polarizer, and the first and second regions are a half wavelength with respect to light having a first wavelength in the visible light wavelength region. Each of the third and fourth regions functions as a quarter-wave plate with respect to light having a second wavelength in the visible light wavelength region. Item 11. The optical kit according to Item 9 or 10, wherein the functions of the slow axis are different from each other.
[12] When the structure has been irradiated with light having the first wavelength from the first polarizer side, the first and second linearly polarized lights in which the polarization planes of the first and second regions are orthogonal to each other. In the item 11, the slow axis of each of the third and fourth regions is parallel or perpendicular to the polarization plane of the first linearly polarized light in the structure. The optical kit as described.
[13] The first and second structures can be formed as the structure, wherein the angles of the transmission axes of the second polarizer and the slow axes of the third and fourth regions are different from each other. 12. The optical kit according to 12.

  DESCRIPTION OF SYMBOLS 10 ... Optical element, 10a ... part, 10b ... part, 11 ... Support body, 12a ... Covering layer, 12b ... Covering layer, 13a ... Polarizer, 13b ... Polarizer, 14H ... Retardation layer, 14Q ... Retardation layer, 15 ... cholesteric liquid crystal layer, 17a ... landmark, 17b ... landmark, 19 ... perforation, 20 ... light source, 30 ... observer.

Claims (4)

  1. The first and second polarizers, the first retardation layer including the first and second regions having different slow axis directions or different refractive index anisotropies, and the slow axis A second retardation layer including third and fourth regions having different orientations or refractive index anisotropies from each other, and a cholesteric liquid crystal layer, the arrangement of which is the first and The first state where the second polarizer is not facing, the first and second polarizers are facing each other, the cholesteric liquid crystal layer is interposed between the first and second polarizers, and the first retardation layer is The second phase difference layer is interposed between the first polarizer and the cholesteric liquid crystal layer, and the second retardation layer is changeable between a second state interposed between the second polarizer and the cholesteric liquid crystal layer. an optical element, by bending the optical element, The arrangement can be changed from the first state to the second state, and when the arrangement is changed from the first state to the second state, the optical element has the first and second states. polarizer, said first and second retardation layer and the that have indicia is provided for aligning a portion of the cholesteric liquid crystal layer to a portion of another light optical element.
  2. Each of the first and second polarizers is a linear polarizer, and the first and second regions are respectively half-wave plates for light having a first wavelength in the visible light wavelength region. And the directions of the slow axes are different from each other, and the third and fourth regions each function as a quarter-wave plate for light having the second wavelength in the visible light wavelength region. The optical element according to claim 1, wherein directions of slow axes are different from each other.
  3. When the optical element in which the arrangement is in the second state is irradiated with light having the first wavelength from the first polarizer side, each of the first and second regions has a polarization plane. In the optical element in which the first and second linearly polarized light orthogonal to each other are emitted toward the second retardation layer and the arrangement is in the second state, each of the third and fourth regions has a slow axis. The optical element according to claim 2 , wherein the optical element is parallel or perpendicular to a polarization plane of the first linearly polarized light.
  4. Wherein the second state, the second polarizer transmission axis direction is the third and fourth regions each slow angles different from each other two or more states capable of forming claims forms with respect to the axis of the third An optical element according to 1.
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JP5564926B2 (en) * 2009-12-15 2014-08-06 凸版印刷株式会社 Forgery prevention paper and verification method using the same
JP5842495B2 (en) * 2011-09-16 2016-01-13 凸版印刷株式会社 Information recording medium

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CN1163765C (en) * 1997-05-09 2004-08-25 罗利克有限公司 Optical element
JP3826693B2 (en) * 2000-08-25 2006-09-27 凸版印刷株式会社 Information recording medium
JP2003145912A (en) * 2001-11-15 2003-05-21 Toppan Printing Co Ltd Antiforgery printed matter
JP2004351831A (en) * 2003-05-30 2004-12-16 Toppan Printing Co Ltd Antifalsifying method of card, transfer medium for card with antifalsifying measure used for the same and method for judging genuiness of card
DE102004018702B4 (en) * 2004-04-17 2006-05-24 Leonhard Kurz Gmbh & Co. Kg Film with polymer layer
JP4866129B2 (en) * 2006-04-03 2012-02-01 Jx日鉱日石エネルギー株式会社 Identification medium, identification method, and identification apparatus
JP5380773B2 (en) * 2006-11-30 2014-01-08 凸版印刷株式会社 Laminated body, adhesive label, transfer foil, recording medium, labeled article, kit, and discrimination method
JP5141078B2 (en) * 2007-04-04 2013-02-13 凸版印刷株式会社 Security device, printed matter with label and identification method
JP2010107748A (en) * 2008-10-30 2010-05-13 Dainippon Printing Co Ltd Authenticity identification material

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US5045410A (en) 1985-12-13 1991-09-03 Karl Neumayer, Erzeugung Und Vertrieb Von Kabeln, Drahten Isolierten Leitungen Ur Elektromaterial Gesellschaft Mit Beschrankter Haftung Low phosphorus containing band-shaped and/or filamentary material

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