JP2006150932A - Certification medium, certification method and certification system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a certification medium which can be manufactured at a low cost, is highly forgery-resistant and permitting easy judgment of authenticity, a certification method and a certification system. <P>SOLUTION: The certification medium is constituted by forming a plurality of deformation parts having a three dimensional shape formed by a laser processing on the surface of a substrate with a substantially flat surface reflecting at least light with a specified wavelength, or by forming a plurality of refractive index changing parts with a different refractive index from a first refractive index formed by the laser processing on the surface or in the inside of a member with the first refractive index formed of a substance transmitting at least light with a specified wavelength. The authenticity of the certification medium is judged on the basis of an interference pattern formed by reflected light or transmission light when reference light containing the light with the specified wavelength is projected on the certification medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is applicable to securities such as stock certificates, claims, checks, bills, etc., cards such as credit cards and cash cards, certificates such as licenses and passports, and other certificates such as gift certificates, boarding tickets and admission tickets. A proof medium that can be used particularly preferably for a class, a proof method using the proof medium, and a proof system. More specifically, it is highly resistant to counterfeiting and can be manufactured at low cost. The present invention relates to a certification medium, a certification method, and a certification system.

  In many cases, a bank card or a credit card issued by a credit company uses a magnetic card in which a tape-like magnetic recording medium is attached to a plastic card.

  This magnetic card is easy to read and duplicate information recorded on a magnetic recording medium, and forgery and unauthorized use of the magnetic card is a big problem.

  For this reason, in this type of card, counterfeiting measures such as using a personal identification number, an IC chip, a hologram, etc. in magnetic recording are taken.

  However, the personal identification number may be inferred from the user's personal information and the like, and in order to ensure security, the personal identification number must be changed at a certain frequency, which is complicated.

In addition, IC chips are expensive themselves, and there are many companies that do not step into the use of IC chips due to problems such as infrastructure development, and hologram cards are also expensive as well. Although there is a temporary effect as a countermeasure against forgery by color copying, there is a problem that the hologram itself is easily forged because of its simple structure.
JP 2004-252415 A

  In view of the above problems, an object of the present invention is to provide a certification medium, a certification method, and a certification system that can be manufactured at low cost and have high resistance to forgery.

  Another object of the present invention is to provide a proof medium, a proof method, and a proof system that can easily determine authenticity.

  The present invention solves the above-mentioned problems, and is a proof medium composed of a substrate having a substantially flat surface that reflects light of at least one specific wavelength, and a laser is applied to the surface of the substrate. From a proof medium, wherein a plurality of deformed portions having a three-dimensional shape based on processing are formed, or a substrate having a substantially flat surface that reflects light of at least one specific wavelength The proof medium having a plurality of deformed portions provided with a three-dimensional shape based on laser processing on the surface of the substrate is irradiated with reference light including light of the specific wavelength from a predetermined angle, A verification method, wherein authenticity of the verification medium is determined based on an interference pattern formed by reflected light of the reference light from the verification medium, or at least one light having a specific wavelength A proof medium comprising a substrate having a substantially flat surface to be projected, and a proof medium having a plurality of deformed portions provided with a three-dimensional shape based on laser processing on the surface of the substrate. Holding means, reference light irradiating means for irradiating the proof medium stored in the proof medium storage section with reference light including light of the specific wavelength from a predetermined angle, and from the proof medium An authenticating means for photographing the interference pattern formed by the reflected light of the reference light is compared with a reference image registered in advance and the image of the interference pattern photographed by the photographing means. A verification medium authenticity determination system comprising: determination means for determining sex.

  In the present invention, the three-dimensional shape imparted to the deformed portion by laser processing can be changed variously according to the laser irradiation conditions during laser processing, such as the laser irradiation time, laser power, irradiation angle, and focus position. Can do.

  In addition, the interference pattern (including speckle pattern) formed by the reflected light when the reference light is irradiated to a plurality of deformed portions given a three-dimensional shape based on laser processing is the arrangement pattern of each deformed portion, Not only does it change depending on the planar form (the shape and size of the deformed part when observed from the surface side of the proof medium), but also the three-dimensional shape of the deformed part (the deformed part is recessed from the surface of the substrate). If the depth of the concave portion, the shape or size of the bottom surface or the side surface, the shape of the deformed portion is raised from the surface of the substrate, the shape of the outer peripheral surface of the raised portion, It also depends on the size.

  Accordingly, the interference pattern formed by the reflected light when the proof medium according to the present invention is irradiated with the reference light from a predetermined angle is observed, or a pre-registered reference image (the above-mentioned predetermined An image of an interference pattern obtained by irradiating reference light from an angle, which is recorded and stored in advance on a recording medium provided in a certification system, etc. It is determined whether the arrangement of the deformed portion, the planar shape, and the three-dimensional shape are substantially the same as those of the regular proof medium, thereby determining the authenticity of the proof medium. Is possible.

  On the other hand, no matter how the proof medium is observed, analyzed, etc., it is difficult to grasp the three-dimensional shape of each deformed portion given the shape based on laser processing. Even if the three-dimensional shape can be grasped, the fine three-dimensional shape formed by laser processing cannot be reproduced using a micromachine or the like, and furthermore, the same kind of laser device is used. However, it is impossible to reproduce the three-dimensional shape of the deformed portion unless the laser processing conditions for forming the deformed portion of the regular proof medium are known.

  Therefore, the proof medium, the proof method, and the proof system of the present invention have both the characteristic that the authenticity of the proof medium can be determined easily and reliably and the characteristic that the resistance to counterfeiting is extremely high. Can do.

  Further, the proof medium of the present invention can be manufactured at a very low cost due to the ease of laser processing and the like, and is particularly suitable for, for example, event tickets that lose their value after the due date. Can be used for

  The substrate constituting the proof medium of the present invention needs to reflect light of at least one specific wavelength and have a substantially flat surface in the portion where the deformed portion is formed.

  In addition, the certification medium of the present invention has a name, an address, a photograph image of the person, an account number, an issue date, an expiration date, an event, etc. on a portion other than a portion where a plurality of deformation portions are formed. By applying the necessary information such as the due date, place, entrance fee, etc. by printing or other methods, the proof medium of the present invention is a single card such as a credit card or cash card, or a certificate such as a license. It can also be used as other tickets such as gift certificates and admission tickets, and any method such as pasting the proof medium of the present invention in which a plurality of deformed portions are formed on a thin film material Therefore, it is possible to integrate with these cards, certificates, and other tickets and use them as proof of their authenticity.

  In addition, as the reference light used in the proof method and proof system of the present invention, it is preferable to use light having a uniform phase, in particular, monochromatic laser light, which is formed by reflected light from a plurality of deformed portions. The interference pattern can be made clearer, and authenticity can be determined more reliably by computer processing such as pattern matching.

  In the present invention, it is also possible to configure the three-dimensional shape of at least one of the plurality of deforming portions to be different from the three-dimensional shape of the other one deforming portion. It is possible to make it more difficult to grasp the three-dimensional shape of each deformed portion, and to further increase the resistance to forgery.

  Note that the three-dimensional shape of at least one of the plurality of deformation portions is different from the three-dimensional shape of the other deformation portion, and all of the plurality of deformation portions have the same three-dimensional shape. However, it is possible to easily change the three-dimensional shape of each deformed portion by predetermining the laser processing conditions for each deformed portion.

  The deformed portion in the present invention can be a recessed portion formed by irradiating the surface of the substrate with laser light. For example, the substrate is made of a metal plate such as aluminum, stainless steel, or copper, or a thin film. The concave portion can be formed by using a body and irradiating the surface of the substrate with laser light under appropriate conditions.

  Moreover, the deformation | transformation part in this invention can also be made into the protruding part formed by irradiating the laser beam to the surface of a board | substrate.

  Such a raised portion can be formed, for example, by irradiating a surface of a substrate made of a glass substrate and a metal thin film laminated on the glass substrate with a laser beam under appropriate conditions. Is possible.

  This processing method has high processing reproducibility compared with the processing method of the said recessed part, and can make the three-dimensional shape of each protruding part neat and smooth. Therefore, the interference pattern obtained when the proof medium is irradiated with the reference light can be made clearer and more regular, and the authenticity of the proof medium can be judged more easily and reliably. Is possible.

  Although the mechanism of the bulge formation in the above method is not necessarily clarified, it is generally considered that the bulge is formed by gas expansion between the glass substrate and the metal thin film, According to experiments, it has been found that the use of transition metals such as Cr, Mo, W, Fe, Au, and Ag as the metal thin film can facilitate the formation of the raised portions. Moreover, the particularly preferable film thickness range of the metal thin film is 20 to 500 nm, and the metal thin film can be laminated on the glass substrate by vapor deposition, adhesion using an adhesive, or the like.

  The deformation part in the present invention forms a plurality of ridges by irradiating the surface of a substrate made of silicon or quartz glass with laser light under appropriate conditions, and a metal thin film is formed on the surface of the substrate on which the plurality of ridges are formed. It is also possible to form a raised portion formed by laminating layers.

  This processing method has high reproducibility compared with the processing method of the said recessed part, and can make the three-dimensional shape of each protruding part neat and smooth. Therefore, the interference pattern obtained when the proof medium is irradiated with the reference light can be made clearer and more regular, and the authenticity of the proof medium can be judged more easily and reliably. Is possible.

  In this case, the bulge on the substrate is generally considered to be caused by alteration (mainly oxidation) of silicon or quartz glass in the laser irradiation portion. By irradiating the laser beam in a state where a resin of about 3 μm (for example, PMMA resin) is applied, it is possible to prevent adhesion of debris and easily form a bulge having a relatively large size. Lamination of a metal thin film on a substrate made of silicon or quartz glass can be performed by a method such as vapor deposition or adhesion.

  The deformed portion in the present invention is obtained by forming a plurality of ridges by irradiating the surface of a substrate made of silicon or quartz glass with laser light under appropriate conditions, and transferring the ridges to a substrate made of a metal thin film. It can also be a raised ridge.

  In this case, the bulge on the base material is considered to be caused by alteration (mainly oxidation) of silicon or quartz glass as described above. By irradiating a laser beam in a state where a resin (for example, PMMA resin) is applied, adhesion of debris can be prevented, and a bulge having a relatively large size can be easily formed. The protrusion on the substrate can be transferred to the metal thin film by laminating the metal thin film on the substrate on which the protrusion is formed by vapor deposition or adhesion, and then peeling the metal thin film. .

  Also in this processing method, high reproducibility can be obtained as compared with the processing method of the concave portion, and the three-dimensional shape of each raised portion can be neat and smooth. Therefore, the interference pattern obtained when the proof medium is irradiated with the reference light can be made clearer and more regular, and the authenticity of the proof medium can be judged more easily and reliably. Is possible.

  The present invention is also a proof medium that is made of a member that transmits light of at least one specific wavelength and has a first refractive index, and is formed on the surface or inside of the member by laser processing. From a proof medium having a plurality of refractive index changing portions having a refractive index different from the first refractive index, or a member having a first refractive index and transmitting light of at least one specific wavelength The proof medium having a plurality of refractive index changing portions having a refractive index different from the first refractive index formed by laser processing inside the member is formed with a specific wavelength from a predetermined angle. A verification method comprising irradiating a reference light including light and determining the authenticity of the verification medium based on an interference pattern formed by the transmitted light of the reference light from the verification medium; or Little A plurality of refractions which are made of a member having a first refractive index and which transmits light of one specific wavelength and having a refractive index different from the first refractive index formed by laser processing inside the member. And a reference medium containing a light having a specific wavelength from a predetermined angle with respect to the certification medium accommodated in the certification medium accommodating part. Reference light irradiating means for irradiating, photographing means for photographing an interference pattern formed by the transmitted light of the reference light from the certification medium, a pre-registered standard image, and the interference pattern photographed by the photographing means A verification medium authenticity determination system comprising: a determination unit configured to determine the authenticity of the verification medium by comparing the image of the verification medium.

  In the present invention, the refractive index changing portion formed by laser processing is arbitrarily three-dimensional depending on the laser irradiation conditions during laser processing, for example, the laser irradiation time, laser power, irradiation angle, focus position, etc. It is possible to change the shape.

  In addition, the interference pattern (including speckle pattern) formed by the transmitted light when the reference light is irradiated to the plurality of refractive index changing portions formed by laser processing is an arrangement mode or size of the plurality of refractive index changing portions. Not only changes depending on the height, but also changes depending on the three-dimensional shape of the refractive index changing portion or the position in the depth direction in the member.

  Therefore, the interference pattern formed by the transmitted light when the proof medium according to the present invention is irradiated with the reference light from a predetermined angle is observed, or a reference image registered in advance (the above-mentioned predetermined An image of an interference pattern obtained by irradiating reference light from an angle, which is recorded and stored in advance on a recording medium provided in a certification system, etc. It is determined whether the arrangement, the planar shape, the three-dimensional shape, and the position in the depth direction of the refractive index changing portions are substantially the same as those of the regular proof medium, It is possible to determine the authenticity of the certification medium.

  On the other hand, no matter how the proof medium is observed or analyzed, it is difficult to grasp the three-dimensional shape and the position in the depth direction of the individual refractive index change portions formed by laser processing. In addition, even if the three-dimensional shape and the position in the depth direction can be grasped, it is impossible to form a refractive index changing portion inside the medium using a micromachine or the like. Even if the apparatus is used, it is impossible to reproduce the three-dimensional shape of the refractive index changing portion unless the laser processing conditions for forming the refractive index changing portion of the regular proof medium are known.

  Therefore, the proof medium, the proof method, and the proof system of the present invention have both the characteristic that the authenticity of the proof medium can be determined easily and reliably and the characteristic that the resistance to counterfeiting is extremely high. Can do.

  Further, the proof medium of the present invention can be manufactured at a very low cost due to the ease of laser processing and the like, and is particularly suitable for, for example, event tickets that lose their value after the due date. Can be used for

  The material used for the proof medium of the present invention needs to have a property of transmitting light of at least one specific wavelength. For example, it has sufficient transparency with respect to the light of the specific wavelength. Plates such as acrylic and glass, rods, films, and the like can be used.

  Further, the proof medium of the present invention is a part other than the part where the plurality of refractive index changing portions are formed, such as name, address, photographic image of the person, account number, issue date, expiration date, etc. By applying necessary information such as the date of event, place, entrance fee, etc. by printing or other methods, the certification medium of the present invention can be used alone as a credit card, cash card, etc., license, etc. It can also be used as other certificates such as certificates, gift certificates, admission tickets, etc. Also, the proof medium of the present invention in which a plurality of refractive index changing portions are formed on a film-like material is pasted, etc. It is also possible to integrate with these cards, certificates, and other tickets by using any of the methods described above and use them as proof of their authenticity.

  In addition, as the reference light used in the proof method and proof system of the present invention, it is preferable to use light having a uniform phase, particularly monochromatic laser light, and thereby transmitted light from a plurality of refractive index changing portions. The formed interference pattern can be made clearer, and authenticity determination by computer processing such as pattern matching can be made more reliable.

  In the present invention, the laser processing is performed so that the three-dimensional shape of at least one refractive index changing portion of the plurality of refractive index changing portions is different from the three-dimensional shape of the other refractive index changing portion. It is also possible to make it more difficult to grasp the three-dimensional shape of each refractive index changing portion, and it is possible to further increase resistance to forgery.

  Note that the three-dimensional shape of at least one refractive index changing portion among the plurality of refractive index changing portions is different from the three-dimensional shape of the other refractive index changing portion. This means that they do not have the same three-dimensional shape, but since the individual refractive index changing portions in the present invention are formed by laser processing, the laser for each refractive index changing portion By predetermining the processing conditions, it is possible to easily change the three-dimensional shape for each refractive index changing portion.

  In the present invention, a member constituting the proof medium is formed of silicon or quartz glass, and a laser beam is irradiated on the surface of the member, thereby forming a refractive index changing portion protruding on the surface of the member. In this case, since the three-dimensional shape of the refractive index changing portion can be neat and smooth, the interference pattern obtained by the transmitted light when the illumination medium is irradiated with the reference light is clearer and regular. Therefore, it is possible to further increase the ease and certainty of determining the authenticity of the illumination medium.

  As described above, the refractive index changing portion in this case is generally considered to be raised due to alteration (mainly oxidation) of silicon or quartz glass in the laser irradiation portion, and at the same time, the raised portion is caused by this alteration (participation). It is thought that the refractive index of the film changes. Similar to the above, debris adhesion is prevented by irradiating the surface of a base material made of silicon or quartz glass with a laser beam in a state where a resin (for example, PMMA resin) of about 1 to 3 μm is applied. It is possible to easily form a large-sized ridge.

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

  FIG. 1A is an explanatory diagram schematically showing a state in which a recess is formed by irradiating a laser beam 1 on a workpiece 2 that reflects light of at least one specific wavelength such as metal. 1 (b) is an explanatory view schematically showing a change in the cross-sectional shape of the recessed portion 4 formed when the laser power of the laser beam 1 to be irradiated is changed, and FIGS. 1 (c) and 1 (d). These are the conceptual explanatory drawings which show that the interference patterns 6a and 6b of a different aspect are formed with the cross-sectional shape of the formed recessed part 4. FIG.

  As shown in FIG. 1A, a concave portion can be formed on the surface 2 a by irradiating the laser beam 1 from the normal direction of the surface 2 a of the workpiece 2. In the figure, reference numeral 3 denotes a lens system for adjusting the focal point 1a of the laser beam 1. In the illustrated example, the focal point 1a is adjusted so as to be positioned on the surface 2a.

  Further, as shown in FIG. 1B, it is possible to change the three-dimensional shape (cross-sectional shape) of the recessed portion 4 by changing the laser power of the laser beam 1 in FIG. As the laser power is increased, the recessed portion 4 becomes deeper and the angle θ between the bottom surface 4a and the surface 2a increases.

  Even when the laser power of the laser beam 1 is constant, for example, by increasing the irradiation time of the laser beam 1 or increasing the number of times of irradiation of the laser beam 1, the laser beam 1 in FIG. In the same manner as when the laser power is increased, the angle θ formed by the bottom surface 4a and the surface 2a can be changed.

  Further, for example, the position of the focal point 1a is moved in the depth direction of the workpiece 2 (the right direction in FIG. 1A) as the recessed portion 4 is deepened by the irradiation of the laser beam 1. Thus, the concave portion 4 having a small depth and a small angle θ formed by the bottom surface 4a and the surface 2a can be formed, and the optical axis of the laser beam 1 is inclined from the normal direction of the surface 2a. Depending on the conditions of the laser processing, the concave portion 4 having various three-dimensional shapes can be formed, for example, the concave portion 4 whose bottom surface 4a has an asymmetric shape with respect to the normal line of the surface 2a can be formed. Is possible.

  Further, for example, by adjusting the diameter of the focal point 1a by the lens system 3 or using a mask, the planar form of the recessed portion 4 (the shape of the opening of the recessed portion 4 when observed from the surface 2a side) And size) can be changed in various ways.

  When the workpiece 2 in which a plurality of such recessed portions 4 are formed is irradiated with the reference light 5 including the light having the specific wavelength, interference between the reflected light 5a from the surface 2a and the reflected light 5b from the recessed portion 4 occurs. Thus, the interference patterns 6a and 6b are formed.

  In this case, if the arrangement of the plurality of recesses 4 is different, the interference pattern obtained is also different. However, even if the arrangement of the plurality of recesses 4 is the same, the recesses 4 having the same three-dimensional shape. Are arranged (FIG. 1 (c)) and when the concave portions 4 having different three-dimensional shapes are arranged (FIG. 1 (d)), the reflected light 5b from the individual concave portions 4 is reflected. As a result, the interference patterns 6a and 6b having different aspects are formed.

  FIG. 2A is an explanatory view showing a state in which the raised portion 4 is formed by irradiating the workpiece 2 with the laser beam 1, and FIG. 2B is a diagram in which the irradiation condition of the laser beam 1 is changed. It is explanatory drawing which shows typically the change of the three-dimensional shape of the protruding part 4 at the time.

  The workpiece 2 in FIG. 2A is composed of a glass substrate 2s and a metal thin film 2m laminated on the glass substrate 2s by a method such as vapor deposition or adhesion.

  By irradiating the surface 2a of the workpiece 2 with the laser beam 1 focused by the lens system 3, a raised portion 4 having a neat and smooth three-dimensional shape can be formed. Can be used as the substrate 9a constituting the certification medium.

  In general, the raised portion is considered to be generated by the gas expansion 7a occurring between the glass base 2s and the metal thin film 2m due to the energy of the irradiated laser beam 1, and the metal thin film 2m being peeled off from the glass substrate 2s. It has been.

  In this processing method, as shown in FIG. 2 (b), by increasing the laser power and reducing the beam diameter, the planar area (area when observed from the surface 2a side) is reduced and the height is increased. A raised portion 4a having a large dimension (a dimension in the normal direction of the surface 2a) can be formed, and by increasing the laser power and the beam diameter, the planar area is large and the height dimension is large. The raised portion 4b can be formed, and the laser power is reduced and the beam diameter is increased, whereby the raised portion 4c having a large planar area and a small height can be formed. Depending on the conditions, the three-dimensional shapes of the raised portions 4a to 4c can be variously changed.

  Even when the power of the laser beam is constant, for example, the same effect as when the laser power is increased can be obtained by increasing the irradiation time of the laser beam or increasing the number of times of laser beam irradiation. It is possible to adjust not only the laser power and the beam diameter, but also, for example, the irradiation angle of the laser beam to the workpiece 2, change the position of the beam focus during processing, or change the beam shape using a mask. It is also possible to change the three-dimensional shape of the raised portion variously.

  FIG. 3A is an explanatory view showing a state in which the bulge 4 ′ is formed by irradiating the workpiece 2 with the laser beam 1, and FIG. 3B is a diagram illustrating how the irradiation condition of the laser beam 1 is changed. It is explanatory drawing which shows typically the change of the three-dimensional shape of protrusion 4 'at the time.

  The work 2 in FIG. 3A is made of silicon or quartz glass, and the surface 2a of the work 2 is irradiated with the laser light 1 focused by the lens system 3 so that it is neat and smooth. A ridge 4 'having a specific shape can be formed.

  This bulge 4 ′ is considered to be formed by generating a volume increasing region 7 b due to alteration (mainly oxidation) of silicon or quartz glass in the irradiated portion of the laser beam 1.

  The ridge 4 'in the processing method shown in FIG. 3 (a) has a relatively high transparency with respect to the reference light in the visible light region, but as shown in FIG. 3 (b), the metal reflects at least one specific wavelength. A raised portion 4 is formed on the metal thin film 8 by laminating the thin film 8 on the surface 2a of the work 2 by a method such as vapor deposition or adhesion, and a substrate 9b comprising the work (base material) 2 and the metal thin film 8 is formed in the present invention. It can be used as such a proof medium.

  Further, the metal thin film 8 is peeled from the laminate of the workpiece (base material) 2 and the metal thin film 8 obtained by the method of FIG. 3B (FIG. 3C), and the peeled metal thin film 8 is used in the present invention. It is also possible to use the substrate 9c constituting the proof medium. In this case, a large number of substrates 9c are manufactured using a single workpiece (base material) 2 on which a plurality of ridges 4 'are formed. Therefore, mass production of the substrate 9c can be achieved.

  When forming the ridges 4 'on the workpiece (base material) 2, as shown in FIG. 3 (d), the planar area is reduced and the height is increased by increasing the laser power and decreasing the beam diameter. A ridge 4a 'having a large dimension can be formed, and by increasing the laser power and the beam diameter, a ridge 4b' having a large planar area and a large height can be formed. By increasing the laser power and increasing the beam diameter, it is possible to form a bulge 4c ′ having a large planar area and a small height, depending on the conditions of laser irradiation. Thus, it is possible to obtain the substrates 9b and 9c on which the raised portions having various three-dimensional shapes are formed.

  In addition, even when the laser power of the laser beam is constant, for example, the same effect as when the laser power is increased can be obtained by increasing the irradiation time of the laser beam or increasing the number of times of laser beam irradiation. In addition to the laser power and the beam diameter, for example, the irradiation angle of the laser beam to the workpiece 2 is adjusted, the position of the beam focus during processing is changed, or the beam shape is changed using a mask. It is also possible to change the three-dimensional shape of the ridge variously.

  In addition, since the above-described substrates 9a to 9c have mechanical fragility, a resin having sufficient transparency with respect to the light having the specific wavelength in order to prevent deformation of a raised portion or the like due to an external force. It is preferable to coat the front surface, the back surface or the whole of the substrates 9a to 9c.

  4A to 4C show that the interference pattern 6 is formed by irradiating the proof medium composed of the substrates 9a to 9c having the plurality of raised portions 4 with the reference light 5 including the light of the specific wavelength. It is explanatory drawing which shows a mode that it forms, When using the board | substrate 9a or 9b, as shown to Fig.4 (a), the interference pattern 6 is formed with the reflected light when the reference light 5 is irradiated to the surface The interference pattern 6 can be arranged and sized by the same mechanism as described above for the interference pattern formed by the reflected light from the substrate on which a plurality of recesses are formed. , Depending on the three-dimensional shape.

  When the substrate 9c is used, as shown in FIG. 4B, the interference pattern 6 is formed by reflected light when the surface of the substrate 9c is irradiated with the reference light 5, or FIG. As shown in FIG. 4, the interference pattern 6 can be formed by reflected light when the back surface of the substrate 9c is irradiated with the reference light 5. In this case, the interference pattern 6 has a plurality of concave portions. Due to the same mechanism as described above for the interference pattern formed by the reflected light from the substrate, it changes depending on the arrangement, size, and three-dimensional shape of the protrusions 4.

  In FIG. 5A, the refractive index changing portions 4 a to 4 c are formed inside the work 2 by irradiating the work 2 made of a material such as acrylic that transmits light of at least one specific wavelength with the laser light 1. FIG. 5B is an explanatory diagram schematically showing how the interference pattern 6 is formed by transmitted light when the workpiece 2 is irradiated with the reference light 5.

  As shown in FIG. 5A, the refractive index changing portion 4a having a refractive index different from the original refractive index of the workpiece 2 is irradiated by the laser beam 1 whose focal point 1a is positioned inside the workpiece 2 by the lens system 3. ~ 4c are formed.

  The refractive index changing portions 4a to 4c are formed by alteration of the workpiece 2 or generation of bubbles by the laser light 1, and the three-dimensional shape thereof is, for example, a focal point when the workpiece 2 is an acrylic resin. By performing laser irradiation for a predetermined time while keeping the position 1a constant, the isotropic shape close to a sphere like the refractive index changing portion 4a is obtained, and the focal point 1a is set in the thickness direction of the workpiece 2 or Depending on the conditions of laser processing, such as forming a refractive index changing portion that is long or flat in the thickness direction as in 4b and 4c, by performing laser irradiation while moving in a direction perpendicular to Refractive index changing portions having various sizes and three-dimensional shapes can be formed.

  In the example shown in the figure, the work 2 having a flat front surface and back surface is shown, but the size of the interference pattern 6 can be adjusted by forming the front surface and / or the work surface 2 to be concave or convex. Alternatively, when the front and back surfaces have relatively flat portions, it is also possible to obtain the interference pattern 6 using a lens for correcting refraction caused by this.

  Further, the shape of the refractive index changing portion formed by the laser beam 1 varies depending on the material used. For example, when glass is used as the work 2, an elongated crack-like refractive index changing portion is formed.

  When the workpiece 2 is irradiated with the reference light 5 including the light of the specific wavelength, as shown in FIG. 5B, the transmitted light that does not pass through the refractive index changing portions and the respective refractive index changing portions pass through. The interference pattern 6 is formed by the difference in the outgoing angle of the transmitted light from the work 2. This interference pattern is an interference pattern formed by the reflected light from the substrate on which a plurality of recessed portions or raised portions are formed. According to the same mechanism as described above, the refractive index change portion changes depending on the arrangement, size, three-dimensional shape, and the like.

  Further, as described above with reference to FIGS. 3A and 3D, the laser light focused by the lens system 3 on the workpiece 2 made of silicon or quartz glass, which is a material that transmits light of at least one specific wavelength. By irradiating 1, it is possible to form a refractive index changing portion 4 ′ having a plurality of protrusions on the surface 2 a of the work 2, and such a plurality of refractive index changing portions 4 ′ are formed. When the workpiece 2 is irradiated with light of the specific wavelength in the same manner as in FIG. 5B, the interference pattern 6 that changes depending on the arrangement, size, three-dimensional shape, etc. of the refractive index changing portion 2 It is possible to obtain.

  In addition, the workpiece | work 2 in this case does not need to be flat in the surface and / or back surface similarly to the above.

  FIGS. 6A to 6C are explanatory views showing an example of a method for forming a plurality of recessed portions or a plurality of refractive index changing portions in the present invention. As shown in FIG. The work 2 placed on the table 11 that can be moved in the XY plane by the means 10 is irradiated with the laser beam 1 from the laser head 12 through the lens system 3, and FIG. As shown in FIG. 2, the work 2 arranged on the fixed table 11 is irradiated with the laser light 1 from the laser head 12 which is movable in the XY plane by the driving means 10 through the lens system 3. Alternatively, as shown in FIG. 6C, a movable mirror 13 and a lens that can swing a laser beam 1 from a laser head 12 by a driving unit 10 with respect to a workpiece 2 arranged on a fixed table 11. System 3 By a method such as to irradiate a plurality of recessed portions in the present invention, it is possible to form the ridges, or refractive index change portion.

  In each of the above methods, the driving means drives the XY table, the laser head, the movable mirror, the laser power of the laser beam 1 emitted from the laser head 12, the pulse width, the number of pulses, or the focal position by the lens system 3. Such adjustment can be performed by automatic control by a computer.

  Nd: YAG laser (third harmonic, wavelength: 355 nm) is used as the laser for processing the recess, and a substrate made of an aluminum plate, a stainless plate and a copper plate each having a flat glossy surface is used. 9 rows by 9 columns in the form of a matrix of 9 rows and 9 columns (with the spacing between the rows of the matrix and the spacing between the columns set to 100 μm) by the laser light with the focal point narrowed to a diameter of about 10 μmφ positioned on the surface of each substrate. A sample of the proof medium was created by forming the 81 recessed portions.

  At this time, for each of the aluminum plate, the stainless steel plate, and the copper plate, two types of samples were prepared, when the laser power of the Nd: YAG laser was 30 mJ and when it was 10 mJ.

  FIGS. 7 to 9 show the interference patterns formed by the reflected light when the reference light from the He—Ne laser (wavelength 632.8 nm) is irradiated from the predetermined angle around the recessed portion forming portion of these samples. .

  7 to 9 are interference patterns obtained from a sample using an aluminum plate, a stainless steel plate, and a copper plate in this order. In each figure, (a) shows the case where the laser power is 30 mJ, and (b) the laser. The interference pattern when the power is 10 mJ is shown, and it was confirmed that a clear interference pattern was formed in any case.

  In addition, in the case of any material of an aluminum plate, a stainless steel plate, and a copper plate in spite of forming the concave portion of the same arrangement pattern in the same material, the interference pattern of (a) and the interference pattern of (b) However, when the laser power is increased (in the case of (a)), the planar size of the concave portion (the size of the opening when viewed from the surface side) is shown. ) Is large, the angle formed by the bottom surface with respect to the surface is large, and a deep concave portion is formed. Thus, the three-dimensional shape of the concave portion to be formed varies depending on the difference in laser power.

  Similarly, an Nd: YAG laser (second harmonic, wavelength: 532 nm, pulse width: 8 nS, pulse energy 4 μJ / pulse) is used as the laser for processing the raised portion, and the thickness is 1 mm with a flat surface. Using a substrate on which a gold (Au) thin film of about 200 nm is deposited by vapor deposition on a glass substrate, a laser beam in a state where a focal point with a diameter of about 20 μmφ is positioned on the surface of the substrate is used for three rows. A sample of the proof medium was created by forming nine ridges arranged in a three-column matrix (the matrix row spacing and column spacing were both 100 μm). FIG. 10 shows an interference pattern formed by the reflected light when the reference light by the He—Ne laser (wavelength 632.8 nm) is irradiated from the predetermined angle to the portion where the is formed.

  As shown in the figure, the interference pattern obtained from the sample of the certification medium with the raised portion is compared with the interference pattern obtained from the sample of the certification medium with the concave portion (FIGS. 7 to 9). Thus, although the number of raised portions formed on the sample is small, an interference pattern is obtained in which the luminance change is clear, periodic, and easy to determine the center.

  Clear and easy to determine the periodicity and center of interference pattern is obtained because each raised part formed by laser light has a neat or smooth three-dimensional shape compared to the concave part. However, it is possible to obtain an interference pattern that is clear and easy to determine the periodicity and center, so that the authenticity of the proof medium can be judged easily and reliably. Is possible.

  In addition, when the raised portion is formed by laser light, the range of influence of processing around the raised portion is narrow compared to the case where the recessed portion is formed, and therefore the raised portion is formed at a higher density. Therefore, it is possible to reduce the formation area (the area of the matrix in the above) of the raised portion necessary for obtaining the interference pattern, and accordingly, the photograph of the owner on the certification medium. It is possible to make a larger area that can be used for printing of name, address, and other information.

  A plurality of ridges are formed by irradiating a substrate made of silicon or quartz glass with laser light, and a substrate (9b) on which a metal thin film is formed on the substrate on which the plurality of ridges are formed is irradiated with reference light. In this case, it is possible to obtain an interference pattern that is clear and easy to determine the periodicity and the center as described above, or a ridge formed by irradiating a substrate made of silicon or quartz glass with laser light. The same applies to the case where the front or back surface of the substrate (9c) made of a metal thin film having a plurality of raised portions formed by transfer is irradiated with the reference light in the mode shown in FIG. 4 (b) or (c). It is possible to obtain an interference pattern that is clear and easy to determine periodicity and center.

  Also, an Nd: YAG laser (third harmonic, wavelength: 355 nm) is used, an acrylic resin plate with a thickness of 5 mm is used as the material, and the focus is reduced to a diameter of about 10 μmφ, and the thickness of the acrylic resin plate is The laser power was arranged in the vicinity of the center of the direction, and the laser power was set to 30 mJ or 10 mJ and arranged in a matrix of 9 rows and 9 columns (the matrix row spacing and column spacing were both 100 μm). By forming 81 refractive index changing portions, two types of proof media samples were prepared.

  FIGS. 11A and 11B show a He-Ne laser (wavelength) for a sample in which a refractive index changing portion is formed with a laser power of 30 mJ and a sample in which a refractive index changing portion is formed with a laser power of 10 mJ. 632.8 nm) is an interference pattern formed by transmitted light when irradiated with reference light.

  Also in this case, a clear interference pattern is observed from any of the samples, and the refractive index changes of different shapes and sizes are obtained when the laser power is 30 mJ (a) and 10 mJ (b). Since the portions are formed, different interference patterns were observed.

  FIG. 12A shows a proof medium 23 of the present invention integrated with a magnetic card 22 having a magnetic recording medium such as a cash card, that is, formed of a material that reflects at least light having a wavelength of 632.8 nm. Concept description showing a proof system 21 for certifying the authenticity of a proof medium 23 having a plurality of concave portions or ridges formed by laser processing on a medium having a flat surface. FIG.

  In addition to a magnetic information reader (not shown) for reading the information recorded on the magnetic recording medium, the certification system 21 places the slot 24a of the magnetic card 22 and the magnetic card 22 at predetermined positions. By holding, the proof medium holding chamber 24 provided with the holding means 24b, 24c for positioning the proof medium 23 is disposed on the ceiling portion of the proof medium holding chamber 24, and the holding means 24b A He-Ne laser 25 that emits a reference beam 25a having a wavelength of 632.8 nm from a predetermined angle toward the proof medium 23 positioned by 24c (a portion where a concave portion or a raised portion is formed), and The CCD camera 26 disposed at a position for receiving the reflected light 26a from the proof medium 23 by the reference light 25a, the magnetic information reader, He- The e-laser 25, the CCD camera 26, and the like are connected by a circuit (not shown), and when the authenticity medium 23 is irradiated to the memory (hard disk, RAM, etc.) from the predetermined angle, the reference light 25a is reflected. And a computer 27 that records an image (reference image) of an interference pattern formed by the light 26a.

  In this proof system 21, when the magnetic card 22 is inserted from the insertion port 24a and held at a predetermined position by the holding means 24b and 24c, the reference beam 25a is emitted from the He-Ne laser 25 under the control of the computer 27, The interference pattern formed by the reflected light 26 a is photographed by the CCD camera 26, and the image is captured by the computer 27.

  The computer 27 is installed with a collation program for determining the identity between two images by pattern matching, and collates the interference pattern image received from the CCD camera 26 with the reference image recorded in the memory. When identity exceeding a certain reference value is recognized, the magnetic card 22 is determined to be authentic, and cash is determined according to information recorded on the magnetic recording medium or input from a separate operating means. If the reference value is not satisfied, it is determined that the magnetic card 22 is not authentic, and the magnetic card 22 is inserted without receiving input from the operating means. It is to be returned from the mouth 24a.

  As described above, since the certification system 21 is configured to accept only operations on the magnetic card 22 including the regular certification medium 23, it is highly safe against duplication of the magnetic recording medium by unauthorized means such as skimming. Can provide sex.

  FIG. 12B shows a proof system for certifying the authenticity of the proof medium 23 of the present invention integrated with a magnetic card 22 having a magnetic recording medium such as a cash card, as in FIG. FIG. 12A is a conceptual diagram illustrating a medium 21 formed of a material that transmits light having a wavelength of at least 632.8 nm as a proof medium 23, and formed therein by laser processing. The difference is that a proof medium 23 having a plurality of refractive index changing portions is used. For this reason, the reference light 25a from the He-Ne laser 25 is transmitted from the proof medium 23 as transmitted light 26a. The interference pattern emitted and formed by the transmitted light 26 a is photographed by the CCD camera 26 disposed below the magnetic card 22.

  The proof system 21 in FIG. 12B performs the same operation as described above with respect to the proof system 21 in FIG. 12A. Similar to the proof system 21 in FIG. High security against duplication of magnetic recording media can be provided.

  In order to prevent the dimensional change due to the environmental temperature of the proof medium of the present invention, or the recessed part, the raised part, or the refractive index change part of the present invention from affecting the interference pattern, the proof system 21 of the present invention includes: It is preferable to provide temperature adjusting means for adjusting the certification medium positioned by the holding means to a constant temperature.

  The present invention has been described above by taking the proof medium, the proof method, and the proof system according to one embodiment as examples. However, the present invention is not limited to the above embodiment, and is within the scope of the claims. Various modifications are possible.

  For example, the type and wavelength of the laser for irradiating the concave part, the raised part, or the refractive index changing part, or the laser for irradiating the reference light, or the irradiation conditions are described as examples. It is possible to perform processing and irradiation under irradiation conditions other than those illustrated using lasers of types and wavelengths other than those described above.

  In addition, the material used for the proof medium of the present invention, the shape, size, arrangement, etc. of the recessed portion, the raised portion, or the refractive index changing portion are also materials other than those described above, or the shape, size, arrangement. It is possible to change to

  In the example shown in FIG. 12, the case where the proof medium of the present invention is used for a cash card has been described. However, other cards such as a credit card, securities such as stock certificates, bonds, checks, bills, It can be used in the same manner for certificates such as licenses, passports, and other tickets such as gift certificates, boarding tickets and admission tickets. In the example shown in FIG. 12, the proof medium of the present invention is used. Is used in a state where it is integrated with another base material (magnetic card 22 in the example of FIG. 12), but the proof medium of the present invention is a single unit, cash card, other cards, and securities. It can also be used as a certificate, a certificate, or other ticket.

  Further, the proof medium of the present invention, in addition to the concave portion, the raised portion or the refractive index changing portion according to the present invention, in a portion other than the portion where these concave portion, the raised portion or the refractive index changing portion is formed, Colors, letters, patterns, designs, etc. can be given by printing etc. Alternatively, colors, letters, patterns, designs, etc., can be given by laser processing. is there.

  As a laser processing method in this case, there are an SPD method and an LPC method which can be suitably used for the proof medium of the present invention.

The SPD method is a method that is preferably used for drawing gradation on the surface of a proof medium formed of a plastic material such as an acrylic resin and an image with a visual effect. For example, it is divided into small pieces of 2 × 2 mm ² ), and drawing is performed while independently changing the gradation and visual effect according to the processing area by the laser in each small piece and the dot density. Noriyo Kajita et al., “Artistic plastic processing of small piece division processing using slab type CO ₂ laser” (Laser Research, 2002, Vol. 30, No. 7).

  FIG. 13 (a) shows various pallets used by this SPD method, and each pallet is composed of 16 small pieces arranged in a square, and the larger the processing area in each small piece ( Bright gradation is expressed (as the palette on the right side in FIG. 13 (a)), and the visual effect becomes smoother as the number of processed dots in each piece increases (as the upper palette in FIG. 13 (b)). Is to be expressed.

  FIG. 13B is a figure drawn by the SPD method based on the painting of FIG. 13C. As shown in FIG. 13D which is an enlarged view of the figure, the gradation and the visual effect are dots. It is expressed by a set of irradiation.

The LPC method coloration by dye into the surface of the proof medium formed by a plastic material such as acrylic resin, a method is preferably used in the drawing, the details of which Sakurada Ten'yo "slab by like CO ₂ "Laser plastic coloring method using laser" (Laser Research, 2004, Vol. 32, No. 3).

  FIG. 14 is an explanatory view showing the coloring principle by the LPC method, in which a fibrous sheet 32 made of cellulose or the like impregnated with a disperse dye is disposed on a work 31 formed of an acrylic resin plate or the like, and a laser beam. The colored region 34 is formed by a local temperature increase due to the irradiation of 33, and multicolor drawing is performed by combination with coloring using another fibrous sheet 32 impregnated with a dye of a different color. Is possible. In the case of performing multicolor drawing, it is possible to prevent color mixing with the dye already fixed on the work 31 by interposing the mask 35 between the fibrous sheet 32 and the work 31.

(A) is explanatory drawing which shows typically the aspect in which a recessed part is formed with a laser beam. (B) is explanatory drawing which shows typically the change of the cross-sectional shape of the recessed part formed when the laser power of a laser beam is changed. (C), (d) is a conceptual explanatory drawing which shows that the interference pattern of a different aspect is formed with the cross-sectional shape of a recessed part. (A) is explanatory drawing which shows typically the aspect in which a protruding part is formed with a laser beam. (B) is explanatory drawing which shows the relationship between laser irradiation conditions and the three-dimensional shape of a protruding part. (A) is explanatory drawing which shows typically the aspect in which a protrusion is formed with a laser beam. (B), (c) is explanatory drawing which shows the formation method of the board | substrate which comprises a certification | authentication medium. (D) is explanatory drawing which shows the relationship between laser irradiation conditions and the three-dimensional shape of a protrusion. (A)-(c) is explanatory drawing which shows notionally a mode that an interference pattern is formed by irradiating a reference medium to the certification | authentication medium which has a some protruding part. (A) is explanatory drawing which shows typically the aspect in which a refractive index change part is formed with a laser beam. (B) is explanatory drawing which shows typically a mode that an interference pattern is formed with the transmitted light from a certification | authentication medium. (A)-(c) is explanatory drawing which shows the example of the formation method of several recessed part in this invention, or several refractive index change part. Explanatory drawing which shows the example of the interference pattern formed with the reflected light from a certification | authentication medium. Explanatory drawing which shows the example of the interference pattern formed with the reflected light from a certification | authentication medium. Explanatory drawing which shows the example of the interference pattern formed with the reflected light from a certification | authentication medium. Explanatory drawing which shows the example of the interference pattern formed with the reflected light from a certification | authentication medium. Explanatory drawing which shows the example of the interference pattern formed with the transmitted light from a certification | authentication medium. (A), (b) is explanatory drawing which shows the exemplary structure of the proof system which concerns on one embodiment of this invention. (A) is explanatory drawing of the pallet used in SPD method. (B) is explanatory drawing which shows an original picture. (C) is a figure drawn by the SPD method based on the original picture of (b). (D) is an enlarged view of the figure shown in (c). It is explanatory drawing which shows the coloring principle by LPC method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam 2 Work piece 3 Lens system 4 Concave part, raised part, raised part, refractive index change part 5 Reference light 6 Interference pattern 7a Gas expansion 7b Alteration area | region 8 Metal thin film 9 Substrate 10 Driving means 11 Table 12 Laser head 13 Movable mirror 21 Proof system 22 Magnetic card 23 Proof medium 24 Proof medium holding chamber 25 Laser 26 CCD camera 27 Computer 31 Work 32 Fiber sheet 33 Laser beam 34 Colored area 35 Mask

Claims (15)

  A verification medium comprising a substrate having a substantially flat surface that reflects light of at least one specific wavelength, and a plurality of deformed portions provided with a three-dimensional shape based on laser processing on the surface of the substrate A proof medium characterized in that is formed.   2. The proof medium according to claim 1, wherein a three-dimensional shape of at least one of the plurality of deforming portions is different from a three-dimensional shape of the other one of the deforming portions.   The proof medium according to claim 1, wherein the deformed portion is a recessed portion formed by irradiating the surface of the substrate with laser light.   The proof medium according to claim 1, wherein the deformed portion is a raised portion formed by irradiating the surface of the substrate with laser light.   The proof medium according to claim 4, wherein the substrate comprises a glass base material and a metal thin film laminated on the glass base material.   The proof medium according to claim 4, wherein the substrate includes a glass base material and a transition metal thin film formed on the glass base material. The substrate is formed of a base material made of silicon or quartz glass and a metal thin film laminated on the base material,
On the surface of the base material, a plurality of ridges are formed by laser light irradiation,
The proof medium according to claim 1, wherein the deformable portion is a raised portion formed by laminating the metal thin film on the base material on which the plurality of raised portions are formed. The substrate is a metal thin film;
The deformed portion is a raised portion formed by transferring a raised portion formed by irradiating a base material made of silicon or quartz glass having a substantially flat surface with laser light onto the metal thin film. The proof medium according to claim 1 or 2.   For a proof medium comprising a plurality of deformed portions, each of which is composed of a substrate having a substantially flat surface that reflects light of at least one specific wavelength, and is provided with a three-dimensional shape based on laser processing on the surface of the substrate Irradiating reference light including light of the specific wavelength from a predetermined angle, and determining the authenticity of the verification medium based on an interference pattern formed by reflected light of the reference light from the verification medium Proof method characterized by performing. A verification medium having a plurality of deformed portions each having a substantially flat surface that reflects light of at least one specific wavelength and having a three-dimensional shape based on laser processing is provided on the surface of the substrate. Proof medium holding means for holding at the position;
Reference light irradiating means for irradiating the proof medium accommodated in the proof medium accommodating portion with reference light including light of the specific wavelength from a predetermined angle;
Imaging means for imaging an interference pattern formed by reflected light of the reference light from the certification medium;
A verification medium comprising: a determination unit that determines the authenticity of the verification medium by comparing a reference image registered in advance with an image of the interference pattern captured by the imaging unit. Authenticity determination system.   A proof medium comprising a member that transmits light of at least one specific wavelength and has a first refractive index, wherein the first refractive index is formed on the surface or inside of the member by laser processing. A proof medium comprising a plurality of refractive index changing portions having different refractive indexes.   12. The three-dimensional shape of at least one refractive index changing portion among the plurality of refractive index changing portions is different from the three-dimensional shape of the other refractive index changing portion. Proof medium. The member is made of silicon or quartz glass;
The proof medium according to claim 11 or 12, wherein the refractive index changing portion is a raised portion formed by irradiating the surface of the member with laser light.   A plurality of refractions having a refractive index different from the first refractive index formed by laser processing inside the member, which is configured by a member that transmits light of at least one specific wavelength and has a first refractive index. A proof medium having a rate changing portion is irradiated with reference light including light of the specific wavelength from a predetermined angle, and based on an interference pattern formed by transmitted light of the reference light from the proof medium A proof method comprising: determining authenticity of the proof medium. A plurality of refractions that are made of a member that transmits light of at least one specific wavelength and that has a first refractive index, and that has a refractive index different from the first refractive index formed by laser processing inside the member. A proof medium storage section for storing a proof medium having a rate changing section;
Reference light irradiating means for irradiating the proof medium accommodated in the proof medium accommodating portion with reference light including light of the specific wavelength from a predetermined angle;
Imaging means for imaging the interference pattern formed by the transmitted light of the reference light from the certification medium;
A verification medium comprising: a determination unit that determines the authenticity of the verification medium by comparing a reference image registered in advance with an image of the interference pattern captured by the imaging unit. Authenticity determination system.

Images