KR102653739B1 - Forgery prevention means applicable to barometric color authentication and external stimulus authentication and forgery authentication method using the same - Google Patents

Abstract

The present invention provides a means for preventing counterfeiting and falsification, which enables piezochromic authentication through a piezochromic fluorescent layer and enables authentication through buckling when an external stimulus is applied to layers having different Young's moduli, and a counterfeiting and forgery authentication method using the same. It's about.

Description

Forgery prevention means applicable to barometric color authentication and external stimulus authentication and forgery authentication method using the same}

The present invention relates to a means for preventing counterfeiting and falsification to which piezochromic authentication and external stimulation authentication can be applied, and to a counterfeiting and forgery authentication method using the same. More specifically, the present invention relates to a counterfeiting and forgery authentication method using the same. More specifically, the present invention relates to a counterfeiting and counterfeiting authentication method that enables piezochromic authentication through a piezochromic fluorescent layer and has different Young's moduli. It relates to a means of preventing forgery and forgery that can be authenticated by buckling when an external stimulus is applied to the layer, and a method of authenticating forgery using the same.

In modern times, various new products are being developed according to technological advancements, and transactions of the developed products are actively taking place online. However, unfortunately, cloning technology has also advanced greatly, making it difficult to distinguish between genuine and replica products. In the case of high-priced products, various anti-counterfeiting technologies are applied, but in the case of somewhat low-priced products that are inevitably distributed in large quantities, it is difficult to apply them, and in the case of items such as food, medical products, and cosmetics, they are directly related to human health and even life. It appears that social attention is needed.

Among anti-counterfeiting technologies, the anti-counterfeiting system using a photonic crystal-based pattern, which is widely used, has the disadvantage of being always visible in the presence of light, which is not suitable for hiding information, so its utility as an anti-counterfeiting system is limited.

Accordingly, much development is being conducted on a new type of anti-counterfeiting device that has a fast response to external stimuli (tensile, compression, bending, torsion, etc.) using a reflective method that allows structural color to appear.

In the case of an anti-counterfeiting device that is responsive to the external stimulus, a layer of a flexible material with a predetermined rigidity is built into the device, and the device is loaded using an external stimulus authentication method such as tension, compression, twisting, or bending. You can display an image based on the structural color that appears by adding .

Recently, with the popularization of smartphones capable of polarized light authentication, authentication methods that irradiate polarized light to liquid crystals to reveal inherent hidden marks are increasingly being used and advanced.

One of the polarized liquid crystals capable of forgery authentication is cholesteric liquid crystal, which forms a spiral structure in which molecules in each layer are twisted at a certain angle. This has been applied to LCD panels mainly used in mobile phones, and has recently been widely used for counterfeit labels. It is being used.

In addition, interest in technologies that enable fluorescence control in solid phases is also increasing, and among them, piezochromic fluorescence technology exists.

This is due to changes in the secondary bonding forces between molecules such as pi-pi interaction, hydrogen bonding, and van der Waals force in the chemical structure of the material due to pressure or physical force, resulting in changes in fluorescence color or intensity, and heat treatment. This is a phenomenon in which the original fluorescence returns to the red fluorescence. More simply, there is a strong hydrogen bond in the crystal that emits red fluorescence, and when external pressure is applied, these hydrogen bonds are broken and the molecular packing structure changes, causing green fluorescence. You will see a phenomenon of change. Depending on the original structural characteristics of the molecule, it may move to a short or long wavelength after pressure is applied.

However, in the case of anti-counterfeiting means including the above-mentioned fluorescent layer, there is a disadvantage in that the method of producing prints is complicated and the cost is excessive, and as counterfeiting technology gradually evolves, a single application of a specific method of anti-counterfeiting means is not necessary. Since we may not be prepared for forgery and alteration technology, various counterfeit prevention measures have become necessary.

The object of the present invention is to provide a means for preventing counterfeiting and falsification that includes a piezochromic fluorescent layer, enables piezochromic authentication, and enables authentication through buckling when an external stimulus is applied to layers with different Young's moduli, and counterfeiting using the same. We would like to provide an authentication method.

According to one embodiment of the present invention, a first layer; a second layer located on top of the first layer and including a piezochromic fluorescent material; a third layer located below the first layer, formed of a flexible material, and including a high wrinkle area and a low wrinkle area; a fourth layer patterned in the high wrinkle area, made of a material with a Young's modulus greater than that of the third layer, and adhered to the third layer; and a fifth layer bonded to cover the low radius area and the fourth layer and formed of a material having a Young's modulus greater than that of the third layer and less than that of the fourth layer. may include.

In an exemplary embodiment, the second layer including the piezochromic fluorescent material and the fourth layer patterned in the high wrinkle area of the third layer may be disposed at different positions in the horizontal direction of the layer.

In an exemplary embodiment, a sixth layer located between the first layer and the second layer and printed with a specific shape, and a cholesteric layer located between the second layer and the sixth layer and printed with a hidden shape. It may further include a seventh layer containing liquid crystal.

In an exemplary embodiment, the second layer includes a piezochromatic fluorescent material having a pi-conjugated system, wherein the piezochromatic fluorescent material has a non-planar structure, and the basic skeleton has a benzene ring, which is a pi system, on both sides. More than one group is bonded, has at least one electron-donating group and at least one electron-receiving group, and the basic skeleton includes fluorine, carbazole, and dithienosilole. is selected from, and the group giving the electron is selected from the group including an alkylamino group, an arylamino group, an alkyl alkoxide group, and a mixture thereof, and the electron is given The receiving group may be selected from the group including a cyano group, a nitro group, a fluoroalkyl group, and mixtures thereof.

In an exemplary embodiment, the pressure-chromic fluorescent material may contain 0.01 to 5% based on the weight of the second layer.

In an exemplary embodiment, the pressure-chromic fluorescent material has (a) average particle diameter: 10-150 nm; and (b) fluorescence wavelength: 450-650 nm.

In an exemplary embodiment, the seventh layer includes a first display layer and a second display layer, and at least one of the first display layer and the second display layer is made of ink containing cholesteric liquid crystal. Can be printed.

In an exemplary embodiment, the third to fifth layers are a single load selected from bending load, compression load, tensile load, shear load, or torsion load, or two or more combined loads, and wrinkles are formed due to the wrinkles. By creating multiple grating structures, different structural colors and images based on the structural colors can be formed.

In an exemplary embodiment, if the third layer is formed to have a refractive index of 96% to 104% of the fourth layer and the fifth layer, and the wrinkle-shaped grating structure is not formed due to a load, the fourth layer The layer and the fifth layer may display a color similar to or the same as that of the third layer and may be hidden in the third layer 113.

In an exemplary embodiment, in the forgery authentication method using a forgery prevention means, when UV irradiation and vertical pressure are applied to the second layer, the fluorescence wavelength of the piezochromic fluorescent material changes to confirm whether forgery or alteration has occurred. steps; and a step of confirming forgery by the structural color appearing by applying a load from the third to fifth layers having different Young's moduli using an external stimulus authentication method.

The present invention enables piezochromic authentication by including a piezochromic fluorescent layer, and enables authentication using a buckling method when an external stimulus is applied to layers with different Young's moduli, thereby increasing the anti-counterfeiting effect. .

Figure 1 shows a cross-sectional view of a means for preventing counterfeiting and falsification according to an embodiment of the present invention.
Figure 2 shows a cross-sectional view of a forgery prevention means according to another embodiment of the present invention.
Figure 3 shows a cross-sectional view of firstly checking whether forgery or tampering by applying a UV lamp and pressure, and secondarily checking whether forgery or tampering by applying an external stimulus such as a bending load.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows a cross-sectional view of a means for preventing counterfeiting and falsification according to an embodiment of the present invention.

According to one embodiment of the present invention, a first layer 111, a second layer 112 located on top of the first layer 111 and containing a piezochromic fluorescent material, and the first layer 111 A third layer 113 is located at the bottom of the layer and is made of a flexible material and includes a high wrinkle area and a low wrinkle area, and a pattern is formed in the high wrinkle area and has a Young's modulus greater than that of the third layer 113. The branches are made of a material, and a fourth layer 114 is adhered to the third layer 113 and is bonded to cover the low wrinkle area and the fourth layer 114, and is larger than the third layer 113. It may include a fifth layer 115 made of a material with a Young's modulus smaller than that of the fourth layer 114.

The first layer 111 is located in the center of the anti-counterfeiting means according to an embodiment of the present invention, is located on the top, and enables piezochromic authentication through the second layer 112 including a piezochromic fluorescent layer. , It has a structure that allows buckling authentication by applying a load to the third layer 113 to the fifth layer 115 located on the opposite side.

More specifically, the first layer 111 is a general base layer and can be made of various films used to manufacture labels, such as synthetic resin, paper, or metal.

Next, a second layer 112 containing a piezochromic fluorescent material may be disposed on top of the first layer 111, where the piezochromic fluorescent material is present in an amount of 0.01% or more by weight of the second layer 112. It may contain less than 5% by weight.

If the amount of the piezochromic fluorescent material is less than 0.01% based on the weight of the second layer 112, the piezochromic fluorescence effect may be minimal, and if it exceeds 5%, transparency may decrease, so it is preferable to make it somewhere in between.

In addition, (a) average particle diameter of the piezochromic fluorescent material: 10-150 nm; and (b) fluorescence wavelength: 450-650 nm.

The second layer 112 includes a piezochromatic fluorescent material having a pi-conjugated system, wherein the piezochromatic fluorescent material has a non-planar structure, and at least one benzene ring, which is a pi system, is bonded to the basic skeleton on both sides. There is at least one group that donates electrons and one group that receives electrons.

The piezochromic fluorescent material disclosed in the present invention is one of the fluorescent materials having a pi-conjugated system including an electron-donating group and an electron-receiving group, and it generally requires an intramolecular pi-conjugated system to allow movement of electrons. This is because it is easy to use and the resulting fluorescence properties can appear.

In other words, the more delocalized the pi-conjugated electrons in the molecular structure of a fluorescent material are, the easier the electron movement is. Such a structure has repeating single and double bonds, and the electron distribution is uniform, resulting in a planar structure.

Fluorescent materials with such a planar structure have high fluorescence efficiency in a solution state, but when they are in a solid or thin film state, excimers are formed through intermolecular interactions and ππstacking, resulting in quenching and quantum Efficiency, that is, fluorescence intensity, becomes weaker.

Therefore, the piezochromic fluorescent material is designed to have a non-planar structure, so the fluorescence intensity in the initial state is weak, but as it becomes a solid state, it is stacked in a twisted structure to induce aggregation, thereby interfering with excimer formation, thereby increasing fluorescence efficiency. It is called Aggregation Induced Emission.

In addition, the piezochromic fluorescent material may include an intramolecular electron donating group (EDG, electron donating group) and an electron accepting group (EAG, electron accepting group) to facilitate pi-conjugated electron transfer by pressure. , It can be structured to have a pi-conjugated system with a low HOMO-LUMO energy band gap to facilitate electron transfer.

The piezochromic fluorescent material has a non-planar structure, and its basic skeleton may be made of one or more selected from the group including fluorene, carbazole, and dithienosilole.

In addition, the electron-donating group is selected from the group including an alkylamino group, an arylamino group, an alkyl alkoxide group, and a mixture thereof, and the electron-receiving group It may be selected from the group including a cyano group, a nitro group, a fluoroalkyl group, and mixtures thereof.

Next, it may include a sixth layer 116 that is located between the second layer 112 and the first layer 111 and is printed with a shape distinct from the seventh layer 117, which will be described later.

The sixth layer 116 may be composed of a pair of design printing layers made of different colors, and each design printing layer may be composed of different colors such as white and black, and may be made of different colors depending on the purpose of authentication. Colors can be arranged.

In one embodiment, one design print layer of the sixth layer 116 is made of a print layer with a specific pattern printed with general ink, and the other design print layer is made of liquid crystal ink containing a complementary dye. It may be printed or made of a liquid crystal film containing a complementary dye, where the color of the complementary dye may be a color that has a complementary contrast relationship with the color of the dye contained in the general ink.

Here, the complementary color contrast relationship is a relationship between colors that are symmetrical to each other in Munsell's color wheel or practical color system color wheel, and when viewed side by side, such as orange and sea blue, yellow and indigo, each color changes due to the influence of the other. It can refer to a combination of colors that make the color appear more intense and vivid.

In addition, due to a pair of design printing layers made of different colors, the pattern can be seen with the naked eye even when non-polarized light is irradiated, and it can be printed with general ink or liquid crystal ink containing complementary dye.

In addition, the pattern constituting the design print layer forming the sixth layer 116 may be configured in various forms, and it is preferably provided as a pattern that can be digitally authenticated by a display device, such as a QR code or BAR code.

In addition, it may further include a seventh layer 117 that is located between the second layer 112 and the sixth layer 116 and includes cholesteric liquid crystal with a hidden pattern printed on it.

Here, the seventh layer 117 may have a thickness of about 15 μm or less and may include a first display layer 117a and a second display layer 117b.

At least one of the first display layer 117a and the second display layer 117b may be printed with ink containing cholesteric liquid crystal to have hidden marks, and the remaining display layers may be printed using general ink. It can be.

The cholesteric liquid crystal included in any one or more of the first display layer 117a and the second display layer 117b of the seventh layer 117 is one of the polarized liquid crystals capable of forgery and tampering authentication, and the molecules in each layer are It is twisted at a certain angle to form a spiral structure.

When polarized light is irradiated to the surface of the cholesteric liquid crystal, various colors and patterns are externally displayed depending on the arrangement of the molecules, and this latent image development technology can be applied to the seventh layer 117 for anti-counterfeiting means.

In this way, at least one of the first display layer 117a and the second display layer 117b of the seventh layer 117 can be printed with cholesteric liquid crystal ink, and polarized light is irradiated to the surface to create hidden marks. You can check whether it has been forged or altered by identifying it.

Meanwhile, the cholesteric liquid crystal powder may be a cholesteric liquid crystal microcapsule, and the cholesteric liquid crystal microcapsule may have an average diameter of about 10 μm that can be printed.

The first display layer 117a or the second display layer 117b provided with ink containing cholesteric liquid crystals has a weight of cholesteric liquid crystal powder contained based on the total weight of ink containing cholesteric liquid crystals. It may account for 1-30%, and at least a portion of the remaining weight may be accounted for by at least one of the above general inks.

In addition, among the display layers, the display layer containing cholesteric liquid crystal may be a mixture of cholesteric liquid crystal powder and a thermosetting binder, and the weight of the cholesteric liquid crystal powder when mixed with the binder is the sixth layer ( 116) and can be less than 30%, which is the maximum possible for adhesion.

At this time, considering adhesiveness and stability, it is preferable that the heat-curing binder is an acrylate-based binder.

In addition, as the weight of the cholesteric liquid crystal powder increases, visibility during authentication may increase.

In addition, among the total weight of the ink containing the cholesteric liquid crystal, at least a portion of the remaining weight excluding the weight of the cholesteric liquid crystal may be occupied by nematic liquid crystal or liquid crystal polymer rather than general ink.

Through this, part of the total weight of the ink is composed of cholesteric liquid crystals and the remaining part is composed of nematic liquid crystals or liquid crystal polymers, and an electric current is passed through them to adjust the orientation angle of the nematic liquid crystals or liquid crystal polymers, thereby polarizing the light during authentication. When illuminated, the front and back colors can be illuminated differently.

In one embodiment, when all of the first display layer 117a and the second display layer 117b are printed with ink containing cholesteric liquid crystal, the orientation of the cholesteric liquid crystal used in each display layer is different. It is possible to identify hidden marks to check for forgery or alteration.

Next, the third layer 113 to the fifth layer 115 may be disposed on the opposite side of the second layer 112 containing a piezochromic fluorescent material based on the first layer 111.

The third layer 113 may be formed by curing epoxy (EPU) on the upper surface of a substrate (RB) made of polyethylene terephthalate (PET), but is not limited to this and is made of polypropylene or flexible material. It can be made of excellent natural materials, etc., and is preferably made of a soft material that contains a plasticizer and has further improved flexibility.

In addition, it is preferable to further include a process of plasma treating the hardened third layer 113 to strengthen the interfacial bond with the fourth layer 114 formed on the top, and the third layer 113 formed in this way is Young's modulus is preferably in the range of 10 to 20 Mpa.

In addition, the third layer 113 preferably has a thickness of 200 to 300 ㎛, which means that its shape must be easily deformed by external force. If the third layer 113 has a thickness exceeding the above range, the manufacturing cost increases, The thickness becomes thick, making it unsuitable for use as a film, and furthermore, it has the disadvantage of not being able to bend well when exposed to external stimulation, such as bending. If the thickness is less than the above range, durability is weakened and it may be destroyed by external stimulation. The stability of the substrate itself is low, so when wrinkles are formed by bending, wrinkles of random size may be formed rather than wrinkles of uniform size, which has the disadvantage of reducing the visibility of the pattern when it is expressed on the film surface. Because there is.

Next, the fourth layer 114 can be patterned by printing on the upper surface of the third layer 113, more precisely, on the high wrinkle area of the upper surface based on the direction opposite to the third layer 113. The fourth layer 114 is formed of a hard material, and when the shape of the third layer 113 is deformed, micro-sized wrinkles are formed on the surface due to differences in physical properties, and grating is formed by the arrangement of the wrinkles. forms a structure.

At this time, it is preferable that the fourth layer 114 use a material having a Young's modulus value greater than that of the third layer 113, for example, a Young's modulus in the range of 60 Gpa to 80 Gpa. However, here, the numerical range for the Young's modulus values of the third layer 113 and the fourth layer 114 merely suggests a preferable numerical range, so it is not limited thereto and may have various Young's modulus values including the corresponding numerical range. It may be possible. For example, depending on the preferred Young's modulus value of the third layer 113 in the range of 10 to 20 Mpa and the preferred Young's modulus value of the fourth layer 114 in the range of 60 to 80 Gpa, [1/8000 ≤ third layer (113) Young's modulus / 4th layer (114) Young's modulus ≤ 1/3000] can be satisfied.

Next, the fifth layer 115 is formed of a material with a lower Young's modulus than the fourth layer 114, so that when the shape of the third layer 113 is deformed by an external force, a nano layer is formed on the surface due to the difference in physical properties. Wrinkles of any size are formed, forming a grating structure by the arrangement of the wrinkles.

In an exemplary embodiment, the third layer 113 is formed to have a refractive index of 96% to 104% of the fourth layer 114 and the fifth layer 115, and the wrinkle-shaped grating is formed by a load. If the structure is not formed, the fourth layer 114 and the fifth layer 115 display a color similar to or the same as that of the third layer 113 and are hidden in the third layer 113. You can lose.

Here, the third layer 113 must have a refractive index of 96% to 104% of the fourth layer 114 and the fifth layer 115, so that the optical hologram image responds to the input. can be implemented.

More specifically, the fourth layer 114 and the fifth layer 115 do not form a grating structure according to the wrinkle arrangement when no external stimulus is applied, so the structural color does not appear (Covert) 0. It exists as a dimensional grid.

This is because most of the incident light is transmitted due to transmissive transparency due to the same or similar refractive index (R/Cellulose - R/EPU = 0.03) of the third layer 113, fourth layer 114, and fifth layer 115. am.

Accordingly, the fourth layer 114 and the fifth layer 115 can be completely hidden within the third layer 113 without the structural color due to the grating structure formed by the wrinkle arrangement.

Looking at the wrinkle formation principle that forms the grating structure in the present invention, when an external force is applied to the flexible third layer 113 and a bending load is applied in the direction of the fifth layer 115 and the fourth layer 114, the thin and rigid layer 113 is formed. The fifth layer (115) due to mismatch in mechanical properties of the fifth layer (115) and the fourth layer (114) and the third layer (113), which is thicker and softer than the fifth layer (115) and the fourth layer (114). And in the fourth layer 114, a wrinkle arrangement pattern with a periodic width is formed due to buckling type instability.

Here, because there is a relative difference in Young's modulus and thickness of the third layer 113 to fifth layer 115, the wrinkle arrangement pattern is formed differently, and due to this difference, the wrinkle structure formed in the high wrinkle region and the low wrinkle structure are formed. The wrinkle structure formed in the area is different, and as a result, the saturation of the structural color and the image that appears are different.

The third layer 113 to the fifth layer 115 is a single load selected from bending load, compression load, tensile load, shear load, or torsion load, or a wrinkle is formed by two or more combined loads, and the wrinkles cause several layers. By creating a grating structure, different structural colors and images based on the structural colors can be formed, and the type or direction of the load applied to the forgery prevention means is set differently, thereby creating a security effect by forming different images based on the structural colors. can be increased.

As described above, in order to form a grating structure, external stimuli such as bending load, compressive load, tensile load, shear load, or torsion load are applied to create wrinkles and form an image by structural color.

Here, the load applied to the third layer 113 to the fifth layer 115 is bending load, compressive load, tensile load, shearing load, or torsion. Different images can be formed by using different types of load selected from among twisting loads.

In addition, the second layer 112 containing the piezochromic fluorescent material and the fourth layer 114 formed with a pattern in the high wrinkle area of the third layer 113 are disposed at different positions in the horizontal direction of the layer layer. It can be.

More specifically, the second layer 112 containing a piezochromic fluorescent material and the fourth layer 114 formed with a pattern in the high wrinkle area are arranged at different positions in the horizontal direction of the layer layer, that is, not facing each other. It can be formed in a location that is not present.

Accordingly, if a vertical load is applied to the anti-counterfeiting means while irradiated with UV light, forgery can be confirmed by the fluorescent color that appears in a specific shape due to the piezochromic fluorescent material of the second layer 112, and bending load and compression Forgery can be confirmed by the buckling method, in which wrinkles are formed when external stimuli such as load, tensile load, shear load, or torsion load are applied, and the wrinkles create various grating structures. The piezochromic authentication position and the buckling authentication position are Each authentication method is possible within one authentication method by being made up of locations that do not face each other.

As described above, the first layer 111 to the second layer 112 are stacked, and vertical pressure is applied to the second layer 112 containing a piezochromic fluorescent material while irradiated with UV light to determine whether or not it has been forged or altered. can be confirmed, and forgery and alteration can be confirmed by the structural color that appears when an external stimulus such as bending is applied from the third layer 113 to the fifth layer 115 having different Young's moduli.

In addition, polarized light is irradiated to the seventh layer 117, which is disposed between the second layer 112 and the sixth layer 116 and printed with cholesteric liquid crystal ink, to identify hidden marks, resulting in forgery and alteration using polarization authentication. You can check whether or not.

In addition, in the forgery authentication method using a forgery prevention means, forgery and alteration can be confirmed by simultaneously performing photochromic authentication and buckling authentication. For example, when UV irradiation and vertical pressure (including a method of applying a rubbing force to the surface) are applied to the second layer 112, the fluorescence wavelength of the piezochromic fluorescent material changes to check for forgery. can proceed, and the structural color appears when external stimuli such as bending load, compression load, tensile load, shear load, or torsion load are applied from the third layer 113 to fifth layer 115 having different Young's moduli. Through the step of checking for forgery and alteration, it is possible to check each forgery and alteration within a single forgery prevention means, thereby increasing the effectiveness of preventing forgery and alteration.

Even if the effect is not described in the present specification, each of the above-described components may additionally have other effects in the present invention, and new effects that cannot be seen in the prior art are derived according to the organic combination relationship between each of the above-described components. can do.

In addition, the embodiments shown in the drawings may be modified and implemented in other forms, and if implemented including the configuration claimed in the claims of the present invention or implemented within the scope of equivalents, they should be considered to fall within the scope of the rights of the present invention. something to do.

100: Forgery prevention means
111: first layer
112: 2nd layer
113: 3rd layer
114: 4th layer
115: 5th layer
116: 6th layer
117: 7th layer
117a: first display layer
117b: second display layer

Claims (10)

first layer;
a second layer located on top of the first layer and including a piezochromic fluorescent material;
a third layer located below the first layer, formed of a flexible material, and including a high wrinkle area and a low wrinkle area;
a fourth layer patterned in the high wrinkle area, made of a material with a Young's modulus greater than that of the third layer, and adhered to the third layer; and
A fifth layer is adhered to cover the low radius area and the fourth layer, and is formed of a material having a Young's modulus greater than that of the third layer and less than that of the fourth layer,
A sixth layer located between the first layer and the second layer and printed with a specific shape,
It is located between the second layer and the sixth layer, and further includes a seventh layer containing a cholesteric liquid crystal with a hidden shape printed on it,
The seventh layer includes a first display layer and a second display layer, and at least one of the first display layer and the second display layer is printed with ink containing cholesteric liquid crystal,
The first display layer or the second display layer printed with ink containing the cholesteric liquid crystal is a mixture of cholesteric liquid crystal powder and a heat-curing binder, and the weight of the cholesteric liquid crystal powder is equal to the heat-curing binder. When mixed with, it is made up of 30% or less to enable adhesion to the sixth layer,
Among the total weight of the ink containing the cholesteric liquid crystal, at least a portion of the remaining weight excluding the weight of the cholesteric liquid crystal is made of nematic liquid crystal or liquid crystal polymer. According to paragraph 1,
A means for preventing counterfeiting and tampering, wherein the second layer including the piezochromic fluorescent material and the fourth layer patterned in the high wrinkle area of the third layer are disposed at different positions in the horizontal direction of the layer. delete According to paragraph 1,
The second layer includes a piezochromic fluorescent material having a pi-conjugated system,
The piezochromic fluorescent material has a non-planar structure, and has at least one benzene ring, which is a pi system, bonded to the basic skeleton on both sides, and has at least one electron-donating group and at least one electron-receiving group,
The basic skeleton is selected from the group comprising fluorene, carbazole, and dithienosilole,
The electron-donating group is selected from the group including an alkylamino group, an aryl amino group, an alkyl alkoxide group, and mixtures thereof,
Anti-counterfeiting means, characterized in that the group receiving the electron is selected from the group including a cyano group, a nitro group, a fluoroalkyl group, and a mixture thereof. According to paragraph 1,
An anti-counterfeiting means, characterized in that the piezochromic fluorescent material contains 0.01 to 5% based on the weight of the second layer. According to paragraph 1,
The piezochromic fluorescent material is an anti-counterfeiting means, characterized in that it includes the following features.
(a) Average particle diameter: 10-150 nm; and
(b) Fluorescence wavelength: 450-650 nm. delete According to paragraph 1,
The third to fifth layers are wrinkles formed by a single load or a combination of two or more loads selected from bending load, compression load, tensile load, shear load, or torsion load, and the wrinkles create several grating structures, A means for preventing forgery and tampering, characterized in that it forms different structural colors and an image based on the structural colors. According to clause 8,
If the third layer is formed to have a refractive index of 96% to 104% of the fourth layer and the fifth layer, and the wrinkle-shaped grating structure is not formed by the load, the fourth layer and the fifth layer Forgery prevention means, characterized in that it is hidden in the third layer by displaying a color similar to or the same as the color of the third layer. In the forgery authentication method using the forgery prevention means according to any one of paragraphs 1, 2, 4 to 6, 8, and 9,
When UV irradiation is applied toward the second layer and pressure is applied in a direction perpendicular to the second layer, the fluorescence wavelength of the piezochromic fluorescent material changes to check for forgery or tampering; and
A forgery authentication method that confirms forgery through a structural color that appears by applying a load from the third to fifth layers having different Young's moduli using an external stimulus authentication method.