Identification medium

An identification medium can be affixed to cloth or leather products by sewing. A cholesteric liquid crystal layer on which an embossed surface for forming a hologram is formed, is sandwiched between a first supporting member and a second supporting member. A mounting region that can be affixed to clothing, etc., by sewing, is formed.

TECHNICAL FIELD

The present invention relates to an identification medium that can be used, for example, as a means for authenticating that an item is genuine (confirming authenticity) of garments, leather products, and various sewn products.

BACKGROUND ART

Patent Document 1 discloses a technique that transfers holograms onto clothing or synthetic leather. Patent Document 2 discloses an identification medium having an optical characteristic obtained by carrying out a hologram processing on a cholesteric liquid crystal.

Patent Document 1 is Japanese Unexamined Patent Application Publication No. Hei09-34342. Patent Document 2 is Japanese Patent No. 4268336.

Patent Document 1 discloses a technique in which an identification medium that can be used to directly confirm authenticity is formed on sewn products or leather products by transferring holograms to cloth or synthetic leather. However, recently, since holograms can be easily forged, anti-tampering effects cannot be expected, even if conventional holograms are used. In Patent Document 2, in view of the above-described circumstances, an identification medium that cannot be easily forged by forming a hologram on a cholesteric liquid crystal is provided. As a method for affixing this identification medium to objects, transferring, sticking or adhering can usually be used. These affixing methods are preferably used for affixing the identification medium on a smooth surface such as a surface of a passport, a card, a molded product made of resin or metal, a package, etc. However, when the identification medium is affixed on a rough surface such as a surface of a cloth or a leather product, there is a problem in that this identification medium may be illegally reused since peeling off is relatively easy.

In view of such circumstances, an object of the present invention is to provide an identification medium that can be affixed to cloth or leather products by sewing.

DISCLOSURE OF THE INVENTION

A first aspect of the present invention has an identification medium including a cholesteric liquid crystal layer on which a hologram is formed, a first supporting member and a second supporting member between which the cholesteric liquid crystal layer is sandwiched, and at least one thereof is made of transparent material which does not disturb circularly polarized light reflected from the cholesteric liquid crystal layer, and a mounting region that is sewn onto an object.

According to the first aspect of the present invention, a polarized state of circularly polarized light selectively reflected from the cholesteric liquid crystal layer is not disturbed on at least one of two sides, and therefore, optical characteristics of the cholesteric liquid crystal layer can be observed from at least one of the two sides. In addition, the identification medium is affixed by sewing on clothing, leather products, etc., using the mounting region.

As an object to which the identification medium is affixed, clothing or leather products that can be sewn using thread can be used; however, the object is not so limited, as long as it is made of material to which the identification medium can be affixed by sewing. Specifically, as an object, clothing, gloves, hats, socks, mufflers, shoes, bedding, blankets, towels, carpets, handkerchiefs, dish towels, bags, furniture, mats, various sports goods, etc., can be used. The identification medium of the present invention can be sewn to a part made of cloth or leather in these products using thread. Here, the leather may be genuine leather or synthetic leather.

A second aspect of the present invention has an identification medium according to the first aspect, in which at least one of the first supporting member and the second supporting member is a polyurethane film. Discomfort does not occur, even if the polyurethane film is affixed to clothing, leather products, etc., because it is soft and has good texture. In addition, optical characteristics of the cholesteric liquid crystal layer are not degraded since the polarized state of the transmitted light is not disturbed. Furthermore, it has water resistance, and as a result, durability in washing can be obtained, because of the water resistance.

A third aspect of the present invention has an identification medium according to the second aspect, in which the other of the first supporting member or the second supporting member is a cloth, and the mounting region is formed on a part of the cloth.

For example, when the first supporting member and the second supporting member are resin films and a part thereof is affixed to the object such as clothing by sewing using thread, strength of the part is relatively decreased in the same manner as in the case in which perforation is formed in the resin film. Therefore, when the identification medium is attempted to be separated by force from the object, there is a problem in that both supporting members are torn off from a part that forms the above perforation (that is, a part sewn using thread). According to the third aspect of the present invention, since the other supporting member is made of cloth, the strength is prevented from decreasing at the part, even if the part is sewn onto the object using thread.

According to the third aspect of the present invention, an identification medium that is superior in flexibility, strength, durability and texture (pleasant feel to the touch) can be obtained, since a base member is made of cloth. In particular, when the identification medium of the present invention is used as a woven label, the identification medium having the same texture as those of conventional general woven labels, can be obtained.

The cloth may be formed by weaving synthetic fibers such as nylon, polyester, etc. Of course, the cloth may be formed of other fibers. Additionally, the cloth may also be subjected to coloring, printing, embroidery, etc., at a part thereof.

A fourth aspect of the present invention has an identification medium according to the third aspect, further including a resin coating layer on the cloth. According to the fourth aspect of the present invention, a structure that is easily printed on cloth can be obtained. That is, printing on the cloth is often limited due to running of ink, etc.; however, it can be easily carried out by providing the resin coating layer so as to form an undercoating.

In general, common clothing can be subjected to washing (usual washing) using water and detergent and dry cleaning. However, there is a problem in that the adhesive may be deteriorated by coming into contact with cleaning solution, etc. In particular, this problem is substantial because in dry cleaning, organic solvent is used as the cleaning solution. According to the eighth aspect of the present invention, the resin coating layer functions as an infiltrating resistance layer that prevents infiltration of the cleaning solution, and therefore, this problem can be prevented from occurring.

A fifth aspect of the present invention has an identification medium according to the third aspect or the fourth aspect further including a third supporting member made of resin over the cloth. According to the fifth aspect of the present invention, a structure in which liquids are easily infiltrated into cloth can be obtained.

A sixth aspect of the present invention has an identification medium according to any one of the first aspect to the fifth aspect, further including an ink layer in which printing designation is overlappingly carried out on the cholesteric liquid crystal layer, in which the ink layer is visible over the cholesteric liquid crystal layer.

According to the sixth aspect of the present invention, an overlapped state of the hologram formed in the cholesteric liquid crystal layer and the printing designation of the ink layer can be observed. Here, the printing designation of the ink layer may exist on a part that does not overlap the cholesteric liquid crystal layer. According to the sixth aspect of the present invention, superior authentication function can be obtained by overlappingly observing the hologram designation having an optical characteristic of the cholesteric liquid crystal layer that selectively reflects the circularly polarized light at a specific center wavelength and in a specific turning direction and printing designation of the ink layer.

A seventh aspect of the present invention has an identification medium according to the sixth aspect of the present invention, further including a film for printing in which the ink layer is formed. According to the seventh aspect of the present invention, the printing can be easily carried out and can have high durability by using the film for printing, even when the compatibility between the supporting member and the ink is not good.

A eighth aspect of the present invention has an identification medium according to the seventh aspect of the present invention, in which the mounting region is sewn onto the object, in a state in which the film for printing is arranged between the cholesteric liquid crystal layer and the object to be sewn. According to the eighth aspect of the present invention, the film for printing which is inferior in texture (pleasant feel to the touch) will not contact the skin.

A ninth aspect of the present invention has an identification medium according to any one of the first aspect to the eighth aspect of the present invention, in which the first supporting member and the second supporting member have flexibility and can be bent anywhere. According to the ninth aspect of the present invention, a specific visual effect can be obtained when the identification medium is observed in a bent state.

The cholesteric liquid crystal layer exhibits a color shift, in the case in which a viewing angle is changed (in the case in which the cholesteric liquid crystal layer is observed at an angle). For example, when the cholesteric liquid crystal set to have characteristics which exhibit red selectively reflected from the front is observed while inclining obliquely from a vertical direction, a phenomenon in which the color of reflected light gradually shifts from red to orange toward a small wavelength side is observed. According to the ninth aspect of the present invention, by bending the identification medium, the cholesteric liquid crystal layer is bent, and the above color shift can be observed on two sides. With respect to this color shift, color tone changes depending on degree of bending. The color shift generated when the identification medium is bent is a unique phenomenon that cannot be reproduced by forgery, and superior authentication effects can be provided. For example, the color shift is produced on two sides of a part in which the cholesteric liquid crystal is arranged when the identification medium is bent, and the color of the hologram formed in the cholesteric liquid crystal layer changes due to color tone that changes depending on degree of bending. Furthermore, when viewed through a circularly polarized filter, the hologram may or may not exhibit this color change. This optical function cannot be reproduced by forgery, and it is a unique function that is specific to the identification medium.

According to the present invention, an identification medium is provided that can be affixed to cloth, leather products, etc., by sewing.

EXPLANATION OF REFERENCE NUMERALS

Reference numeral100denotes an identification medium,101denotes a supporting film,102denotes an adhesive layer,103denotes a cholesteric liquid crystal layer,104denotes an embossed surface for forming a hologram,105denotes an adhesive layer,106denotes a supporting film,107denotes an ink layer,108denotes a printing film,109denotes an adhesive layer,110denotes a mounting region,200denotes an identification medium,300denotes an identification medium,400denotes an identification medium,500denotes an identification medium,600denotes an identification medium,700denotes an identification medium,701denotes fabric,702denotes a resin coating layer,703denotes an adhesive layer,704denotes a resin film layer,705denotes a printing layer,800denotes an identification medium,910denotes an identification medium, and911denotes a printing layer.

MODE FOR CARRYING OUT THE INVENTION

1. First Embodiment

Structure

FIG. 1shows an identification medium100. The identification medium100has a structure in a sheet shape (a film shape) covered on both surfaces thereof by supporting films101and106, which are an example of a supporting material. As a material for forming the supporting films101and106, thermoplastic elastomer is preferable from the point of view of a feeling of touch and the ability to sew the material. In this example, the support film101and106are formed by a film made of polyurethane, which is one type of thermoplastic elastomer. The supporting films101and106have a thickness of about 10 μm to 100 μm, and preferably have a thickness of about 10 μm to 50 μm. The supporting films101and106are selected from materials that are transparent (visible light passes through), have flexibility (softness), and are waterproof without disturbing the polarized state of visible light as it penetrates. As such a material, a polyurethane film is most preferable. As a material that can be used as the supporting films101and106, an acrylic film, a polycarbonate film, a polyester film, a polyimide film, etc., can be used, other than the polyurethane film.

The supporting films101and106are adhered by an adhesive layer102formed of a transparent adhesive. A cholesteric liquid crystal layer103is sandwiched and held between the supporting films101and106. The cholesteric liquid crystal layer103is set to have optical characteristics in which, for example, red right circularly polarized light is selectively reflected. Here, color (wavelength) of selective reflection and a turning direction of circularly polarized light that is selectively reflected are optionally set, and for example, green left circularly polarized light can be selectively reflected. A structure in which multiple cholesteric liquid crystal layers which selectively reflect colors having a different wavelength are stacked and a structure in which a circularly polarized filter layer is combined with a cholesteric liquid crystal layer, can be used.

The cholesteric liquid crystal layer103has a thickness of about 1 to 10 μm, and an embossed surface for forming hologram104is formed on one surface thereof. The embossed surface for forming hologram104is formed by pressing an embossing die to the cholesteric liquid crystal layer103. According to the embossed surface for forming hologram104, a hologram image can be observed by optical interference when reflected light of the cholesteric liquid crystal layer103is observed. As a hologram image, drawn patterns, character information, various pattern code designations, etc., can be used.

In the structure shown inFIG. 1, the cholesteric liquid crystal layer103is affixed to a supporting film106through a transparent adhesive layer105, and it is affixed to a supporting film101through a transparent adhesive layer102.

Production Method

First, a cholesteric liquid crystal layer103is formed on a substrate (not shown). After the cholesteric liquid crystal layer103is formed on the substrate (not shown), a hologram die (an embossing die) is pressed to an exposed surface thereof, and thereby an embossed surface for forming hologram104is formed. Next, the cholesteric liquid crystal layer103is peeled off from the substrate (not shown), and it is adhered to one surface of a supporting film106by a transparent adhesive layer105. As a result, an intermediate member at a supporting film106side is produced. Here, when the substrate that supports the liquid crystal layer103is made of material that does not disturb a state of polarized light that will penetrate, the cholesteric liquid crystal layer103may be adhered to the supporting film106with the substrates.

On the other hand, a supporting film101having a transparent adhesive layer102is prepared, and an adhering surface thereof is adhered to the intermediate member at the supporting film106side as described above, and therefore, an identification medium100having a cross sectional structure shown inFIG. 1is produced. Here, inFIG. 1, since there is the cholesteric liquid crystal layer103, a state in which the supporting film106is deformed is shown in an exaggerated manner. However, this state is shown by drawings, and the supporting film101side may be deformed, and both of the supporting films101and106may be deformed.

Applied Embodiment

The identification medium100is affixed to an object using a mounting region (a sewing region) shown by reference numeral110. The mounting region110is a part in which the supporting films101and106are adhered by the adhesive layer102. For example, when an object is clothing or leather products, the part of the mounting region110is sewn to a part of the clothing or the leather products or to a tag attached on the clothing or the leather products by a thread. In particular, when a polyurethane film is used for the supporting films101and106, usual sewing can be carried out, and mounting to the object can be carried out by sewing using a usual sewing technique. Here, as a method for affixing the identification medium100to the object, methods such as a hot melting method, etc., can be used. Furthermore, inFIG. 1, one side of the identification medium100is sewn; however, in a manner different from this embodiment, it is possible to sew two sides or all sides thereof.

Optical Function

The identification medium100has the same authentication function on both surfaces thereof. For example, it is viewed from above in the figures. Here, the cholesteric liquid crystal layer103is set to selectively reflect red right circularly polarized light. In this case, when the identification medium100is directly viewed in an environment in which natural light is irradiated, light reflected from the cholesteric liquid crystal layer103is observed, and therefore, a red hologram image is seen.

Then, when the identification medium100is observed through a right circularly polarized filter through which the right circularly polarized light selectively penetrates, the red hologram image is more clearly observed, since the right circularly polarized light which is selectively reflected from the cholesteric liquid crystal layer is selectively observed.

In addition, when the identification medium100is observed through a left circularly polarized filter through which left circularly polarized light selectively penetrates, the right circularly polarized light which is selectively reflected from the cholesteric liquid crystal layer103is cut off by the left circularly polarized filter. Therefore, the light reflected from the cholesteric liquid crystal layer103cannot be observed, and when it is viewed by an observer, the identification medium100is transparent, the hologram is not visible, and the identification medium100can be seen through an opposite side thereof.

The above optical function is the same as that in the case in which the identification medium100is viewed from below in the figure. Similar optical function can be obtained by irradiating the right circularly polarized light instead of observing through the right circularly polarized filter, or by irradiating the left circularly polarized light instead of observing through the left circularly polarized filter.

Advantages

Using a mounting region110without the cholesteric liquid crystal layer103, the identification medium100can be sewn onto clothing or leather products using thread. In particular, when a polyurethane film is used for the support films101and106, it can be easily sewn and has high strength in a sewn state. By sewing the identification medium100onto an object, it is difficult to remove the identification medium100from the object, and illegal reuse of the identification medium100can be prevented.

In addition, since the polyurethane film has flexibility and is waterproof, a structure in which the polyurethane film is used for the supporting films101and106, is preferable to apply to clothing which is likely to contact skin and which is washable. Furthermore, since cholesteric liquid crystal material is inferior in abrasion resistance, a structure in which the material is sandwiched and sealed by polyurethane films is preferable from the point of view of durability.

The cholesteric liquid crystal layer103has the same optical characteristics on both surfaces, and therefore, when the identification medium100is used as a tag for clothing or leather products, it can be authenticated from both surfaces of the tag. It is useful to have a structure that can be authenticated from both surfaces thereof, because two sides of the tag attached to clothing are often inverted by bending.

Additionally, in the case in which the polyurethane film is used for the supporting films101and106, flexibility that is sufficient to simply bend by bending with fingers, can be obtained. The cholesteric liquid crystal layer103has a color shift function in which color changes depending on viewing angle. However, when the identification medium100is also bent, a color shift can be observed, since viewing angles of the cholesteric liquid crystal layer103change. Therefore, for example, when the identification medium100is used as a tag for clothing, the color shift of the cholesteric liquid crystal layer103is observed by bending the tag using fingers, and thereby, it can be used for authentication. This color shift is strongly produced when selectively reflected light is observed using a circularly polarized filter, and as a result, in an observation through the circularly polarized filter, the identification medium100can be authenticated by observing color changes of hologram image when bending.

In addition, when the identification medium100is observed while bending, two sides thereof can be compared. In this case, one of the two bent sides is formed to be convex and the other is formed to be concave, and therefore, a color shift partially having gradation is observed, and moreover, shift states are different on the two sides and are uniquely viewed. The shift state in which the color shift partially showing gradation is observed on the two sides is characteristic and unique and cannot be reproduced by forgery, and a superior authentication function can be produced.

2. Second Embodiment

FIG. 2shows an identification medium200of another embodiment of the present invention. In theFIG. 2, parts denoted by the same reference numerals as those inFIG. 1are equal to parts explained inFIG. 1. This is the same in embodiments shown inFIGS. 3 to 10described below.

The identification medium200shown inFIG. 2is different from the identification medium100shown inFIG. 1, and does not have a transparent adhesive layer105. In the case of the identification medium200, a transparent adhesive layer102is formed on a supporting film101, and next, a cholesteric liquid crystal layer103in which an embossed surface for forming hologram104is formed is affixed thereon. Then, in this state, the identification medium200having a cross sectional structure shown inFIG. 2is produced by adhering a supporting film106on an exposed surface of the transparent adhesive layer102. The identification medium200has a simpler structure than that of the identification medium100. An optical function and an advantage of the identification medium200are the same as those of the identification medium100shown inFIG. 1. Here, the embossed surface for forming hologram104may be formed at an upper side of the figure in the cholesteric liquid crystal layer103(the optical function that can be observed in the hologram image is the same, even if the embossed surface for forming hologram104is formed at an upper side or a lower side of the figure).

FIG. 3shows an identification medium300of another embodiment of the present invention. The identification medium300is different from the identification medium100shown inFIG. 1, in that it does not have transparent adhesive layers102and105. In the case of the identification medium300, a cholesteric liquid crystal layer103in which an embossed surface for forming hologram104is formed is sandwiched between supporting films101and106, and the supporting films101and106made of polyurethane film are affixed to each other by self welding due to heating. The cholesteric liquid crystal layer103is physically sandwiched and held between the supporting films101and106. The identification medium200has a simpler structure than those of the identification mediums100and200. Optical functions and advantages of the identification medium300are the same as those of the identification medium100shown inFIG. 1.

FIG. 4shows an identification medium400of another embodiment of the present invention. The identification medium400has a structure in which an ink layer107is added to the structure of the identification medium100shown inFIG. 1. In the identification medium400, the ink layer107is provided on the supporting film101by direct printing. Designated content of the ink layer107is not limited, and it may be characters, drawn patterns, patterns, various code designations, etc. In addition, the color of the ink layer107is also not limited, and it may be monochrome or a combination of multiple colors. A transparent adhesive layer109is provided on the ink layer107, a cholesteric liquid crystal layer103is affixed on this adhesive layer109, and support films101and106are adhered by the adhesive layer109.

FIG. 4shows a state in which the ink layer107is provided on the entire surface; however, the identification medium400may be a state in which ink exists only in parts, and other parts without the ink allow penetration of visible light. Furthermore, in this embodiment, when the cholesteric liquid crystal layer103is observed through the ink layer107, color and thickness of the ink layer107is set, so that the cholesteric liquid crystal layer103is seen through the ink layer107. Therefore, when the identification medium400is observed from a back surface side (a lower side of the figure), the hologram of the cholesteric liquid crystal layer103can be observed through the ink layer107. In other words, when the identification medium400is observed from a back surface side (a lower side of the figure), a state in which the hologram of the cholesteric liquid crystal layer103overlaps the designation of the ink layer107can be observed. This is the same as the case in which it is observed from a front surface side (an upper side in the figure). Here, a printing content of the ink layer107may be set to be a line drawing, a dot image or an image content with a clearance gap, so that the hologram of the cholesteric liquid crystal layer103is seen from the clearance gap of a part on which the ink is carried.

In the case in which the identification medium has a structure shown inFIG. 4, drawn patterns or characters of printing pattern of the ink layer107are added as identification information to a hologram image when viewed as light reflected from the cholesteric liquid crystal layer103. The printing pattern of the ink layer107can be visually recognized regardless of the existence or turning direction of the circularly polarized filter. That is, when the identification medium is observed while switching right and left circularly polarized filters, an optical function for switching an observation state in which the hologram and the printing pattern are seen to overlap and an observation state in which the hologram is not seen and a printing pattern overlapping the (invisible) hologram are selectively seen, can be obtained.

In addition, designation of the printing pattern of the ink layer107does not exhibit color shift. Therefore, in an observation of a part in which the hologram image of the cholesteric liquid crystal layer103is overlapped with the printing pattern of the ink layer107, the color of the hologram image changes by the color shift when the identification medium400is inclined or bent. However, a state in which the color of the designation of the printing layer107does not change is observed.

FIG. 5shows an identification medium500of another embodiment of the present invention. The identification medium500has a structure in which a film for printing108is added to the structure of the identification medium400shown inFIG. 4. The film for printing108is made of transparent material on which printing may easily be performed and which does not disturb polarization of transmitted light. As material made of the film for printing108that satisfies this condition, for example, a TAC film, polycarbonate film and acrylic film can be used. Here, as a film for printing108, opaque material or transparent material which disturbs the polarization of the transmitted light may be used; however, in this case, the authentication function of the cholesteric liquid crystal layer103viewed from the back surface will be lost.

In the structure shown inFIG. 5, the film for printing108is affixed on a supporting film101by a transparent adhesive layer102. An ink layer107is provided on the film for printing108by printing. A transparent adhesive layer109is provided on the ink layer107, the cholesteric liquid crystal layer103is affixed by the adhesive layer109, and a supporting film106is adhered by the adhesive layer109.

In the case in which polyurethane film is used as a supporting film101, it is difficult to support ink material on the polyurethane film, depending on the type of the ink. In such a case, the ink layer107is easily formed by adding a material film on which the ink may be preferably supported, as a film for printing108.

FIG. 6shows an identification medium600of another embodiment of the present invention. The identification medium600has a structure in which the supporting film101and the adhesive layer102are omitted from the structure of the identification medium500shown inFIG. 5. In the case in which the printing film108is made of opaque material or transparent material that disturbs the polarization of the transmitted light and in the case in which the identification medium is attached so that a back surface does not directly contact skin, the supporting film101can also be omitted, as described above. However, in this case also, an authentication function of the cholesteric liquid crystal layer103viewed from the back surface is lost.

When the identification medium600is attached to clothing, the supporting film106made of a polyurethane film is arranged so as to contact skin. That is, in a state in which the identification medium600is affixed to clothing, which is an object, by sewing, the printing film108is arranged between the cholesteric liquid crystal layer103and the clothing, and in this case, at a position which contacts cloth of the clothing. In this way, the identification medium600is used in a state in which the printing film108does not contact the skin and the supporting film106side contacts the skin, and texture of the polyurethane film can be maintained.

According to the identification medium600, the texture of the polyurethane film can be maintained, printing designation can be easily carried out, and moreover, a simple structure can be formed by using the polyurethane film and as a result, production cost can be reduced.

FIG. 7shows an identification medium700of another embodiment of the present invention. In the identification medium700, cloth701is used as one supporting member, and a supporting film106made of resin is used as the other supporting member. Resin coating layers702are provided at an exposed surface side of the cloth701and an opposite side thereof. For example, the resin coating layers702are made of nylon resin. The resin coating layers702are formed by for example, impregnating liquids into the cloth701and by curing.

A printing layer705is provided close to the resin coating layers702at an upper side in the figure. The printing layer705is formed by printing ink. Characters or drawn patterns are formed at the printing layer705. The resin coating layer702at an upper side in the figure functions as an undercoating of the printing layer705. When the cloth701is used alone, it is difficult to print or it is not suitable for printing fine patterns, depending on the type of ink. However, a suitable state for printing is obtained by providing the resin coating layer702.

In addition, the resin coating layer702functions also as an infiltrating resistance layer which prevents infiltration of liquids. For example, the clothing is generally washed using a detergent and water or is dry-cleaned. In this case, there are problems in that the printing layer705, the adhesive layer102, and the cholesteric liquid crystal layer103are deteriorated or degraded by coming into contact with a cleaning solution. In the structure shown inFIG. 7, these problems are prevented from occurring, since the resin coating layer702functions as an infiltrating resistance layer that prevents infiltration of cleaning solution.

The cloth701is cloth formed by weaving thread made of nylon or polyester. The cloth701in which the printing layer705is formed is adhered to the cholesteric liquid crystal layer103and the supporting film106by the adhesive layer102made of an adhesive. In addition, the same parts as those of the identification medium100shown inFIG. 1correspond to the contents explained inFIG. 1.

In deciding authenticity, the identification medium700is observed from a side of the supporting film106. In this case, when the identification medium700is observed through a right circularly polarized filter, right circularly polarized light selectively reflected from the cholesteric liquid crystal layer103is observed, a red hologram image due to an embossed surface for forming hologram104is clearly visible, and moreover, the drawn patterns of the printing layer705are simultaneously visible.

Then, when the identification medium700is observed through a left circularly polarized filter, right circularly polarized light reflected from the cholesteric liquid crystal layer103is cut off, and therefore, the cholesteric liquid crystal layer103appears transparent, the hologram image is not seen, and the drawn patterns of the printing layer705are preferentially seen. The decision on authenticity is carried out by switching this image.

The identification medium700is affixed to an object by sewing a mounting region (a sewing region)110onto the object using thread. Because the cloth701is cloth, perforations are formed at a sewn part, even if it is sewn onto the object by the thread, and a state in which it is easily torn off from the part is not formed. Therefore, durability against force in which the identification medium700is torn off from the state in which it is sewn onto the object, is high.

When a polyurethane film is used instead of the cloth701, the perforation is formed at the sewn part using thread in the mounting region (the sewing region)110, and strength at the part is lower than that at the other part. Therefore, when the identification medium700is separated from the object by applying more force, the probability that the polyurethane film will break at the sewn part depends on the additional force; however, it is higher than in the case in which the cloth701is used.

In addition, the resin coating layer702has a structure in which the printing layer705is easily formed since it is easily printed. Furthermore, by the resin coating layer702, the cleaning solution is prevented from infiltrating when it is washed using water or is dry-cleaned, and therefore, the printing layer705, the adhesive layer102, the cholesteric liquid crystal layer103, etc., can be prevented from deteriorating or degrading.

When permeability of visible light through the cloth701is low, it is difficult to see the hologram due to embossed surface104from the cloth701side. However, when a cloth701is used that is optically transparent through which the hologram due to the embossed surface104is visible, the resin coating layer702and the adhesive layer102are made of transparent material, and the printing layer705is formed so that an opposite side is visible therethrough, and therefore, the hologram due to the embossed surface104can also be seen from the cloth701side.

As a method for providing optical transparency to the cloth701so that the hologram due to the embossed surface104can be seen, a method in which a cloth having roughness through which visible light can penetrate is used, a method in which a fine thread which is woven in the above cloth having optical transparency is used, a method in which cloth is woven using transparent fiber, and a combination of these methods, can be used.

The identification medium700may have a structure in which the supporting film106is replaced with cloth. In this case, it is preferable that waterproofing processing, such as formation of a resin layer, be carried out, so that the cloth will not be infiltrated by liquids. Here, an embodiment in which cloth is used as a supporting member of the identification medium100is shown; however, supporting members in identification mediums of other embodiments may also be replaced with the cloth. For example, alone or combination, in the identification medium100shown inFIG. 1, the identification medium200shown inFIG. 2, the identification medium300shown inFIG. 3, the identification medium400shown inFIG. 4, the identification medium500shown inFIG. 5, and the identification medium600shown inFIG. 6, cloth may be used as at least one of the supporting members.

FIG. 8shows an identification medium800of another embodiment of the present invention. The identification medium800has a structure in which a resin film704is arranged, instead of the resin coating layer702in the identification medium700, as an infiltrating resistance layer which prevents infiltration of liquids. The resin film704is an example of a third supporting member. The resin film704is made of a polyurethane film similar to the supporting film106. The resin film704is adhered to cloth701by an adhesive layer703.

By arranging the resin film704, a cleaning solution can be prevented from infiltrating into the adhesive layers102and703during cleaning, and the adhesive layers102and703can be prevented from deteriorating or degrading. In addition, texture can be obtained by using a polyurethane film as the resin film704. Here, an infiltrating resistance function for liquids in the structure shown inFIG. 7can also be improved by arranging the resin film704at an outer side (a lower side) of the resin coating layer703, in addition to the structure shown inFIG. 7.

FIG. 9shows an identification medium900. The identification medium900has a structure in which a supporting member which is folded in half one sheet of a supporting film901is used in the identification medium100shown inFIG. 1. That is, the supporting film901is folded in half, and the cholesteric liquid crystal layer103is sandwiched and held between the two sides of the folded supporting film901. In this case, one supporting film902(one supporting member) and the other support film902(the other supporting member) are formed by the folded supporting film901, and the cholesteric liquid crystal layer103is sandwiched and held therebetween. As a foldable supporting film, for example, a polyurethane film can be used. Furthermore, as a foldable supporting material, cloth can be used, and this cloth is folded and a cholesteric liquid crystal layer can be held therebetween.

FIG. 10shows an identification medium910. The identification medium910is an example in which a printing layer911is provided in the identification medium100shown inFIG. 1. In this case, the printing layer911is formed by printing on the cholesteric liquid crystal layer103. The printing on the cholesteric liquid crystal layer103is carried out, for example, using an ink jet method.

In the printing on the polyurethane film, there is a problem in that it is difficult to form a good printing film when compatibility between polyurethane and the ink is not good. Printing designation can be added to the hologram designation of the cholesteric liquid crystal layer in the structure shown inFIG. 1by directly printing on the cholesteric liquid crystal layer103in the same manner as the identification medium910, even if a member for forming a base of the printing is not further used.

The present invention can be used for confirming authenticity.