CA2155382C - Authentication label and authenticating pattern incorporating diffracting structure and method of fabricating them - Google Patents
Authentication label and authenticating pattern incorporating diffracting structure and method of fabricating them Download PDFInfo
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- CA2155382C CA2155382C CA002155382A CA2155382A CA2155382C CA 2155382 C CA2155382 C CA 2155382C CA 002155382 A CA002155382 A CA 002155382A CA 2155382 A CA2155382 A CA 2155382A CA 2155382 C CA2155382 C CA 2155382C
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- Prior art keywords
- diffracting structure
- pattern
- substrate layer
- layer
- light diffracting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0402—Recording geometries or arrangements
- G03H1/041—Optical element in the object space affecting the object beam, not otherwise provided for
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
- B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
- B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
- B42D25/20—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
- B42D25/29—Securities; Bank notes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
- B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
- B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
- B42D25/30—Identification or security features, e.g. for preventing forgery
- B42D25/328—Diffraction gratings; Holograms
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1847—Manufacturing methods
- G02B5/1857—Manufacturing methods using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1861—Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/06009—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code with optically detectable marking
- G06K19/06046—Constructional details
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/08—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means
- G06K19/10—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means at least one kind of marking being used for authentication, e.g. of credit or identity cards
- G06K19/16—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means at least one kind of marking being used for authentication, e.g. of credit or identity cards the marking being a hologram or diffraction grating
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
- G03H1/0011—Adaptation of holography to specific applications for security or authentication
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
- G03H1/024—Hologram nature or properties
- G03H1/0244—Surface relief holograms
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2240/00—Hologram nature or properties
- G03H2240/50—Parameters or numerical values associated with holography, e.g. peel strength
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
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- Y10T428/24355—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
- Y10T428/24364—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] with transparent or protective coating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24355—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
- Y10T428/24372—Particulate matter
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24479—Structurally defined web or sheet [e.g., overall dimension, etc.] including variation in thickness
- Y10T428/24562—Interlaminar spaces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24479—Structurally defined web or sheet [e.g., overall dimension, etc.] including variation in thickness
- Y10T428/2457—Parallel ribs and/or grooves
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24479—Structurally defined web or sheet [e.g., overall dimension, etc.] including variation in thickness
- Y10T428/24595—Structurally defined web or sheet [e.g., overall dimension, etc.] including variation in thickness and varying density
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
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- Y10T428/24628—Nonplanar uniform thickness material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24802—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
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Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Optics & Photonics (AREA)
- Theoretical Computer Science (AREA)
- Business, Economics & Management (AREA)
- Accounting & Taxation (AREA)
- Finance (AREA)
- Manufacturing & Machinery (AREA)
- Credit Cards Or The Like (AREA)
- Holo Graphy (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Abstract
A light diffracting structure in an authenticating pattern especially for an authentication label is used for authenticating and protecting against forgery various valuable objects. The light diffracting structure has unique parameters generating a uniquely coloured pattern. The unique parameters are randomly defined by anisotropic process steps during the manufacturing of the diffractingstructure and are not under full control of the producer. This prevents copying or creating an exact replica thereof. The authenticating pattern comprises an integrated structure of a substrate layer and a transparent overcoat layer and the viewable interface therebetween includes the light diffracting structure. The uniquely coloured authenticating pattern can be verified by simple observation with the naked eye which is a prerequisite for ubiquitous verification.
Description
Authentication Label and Authenticating Pattern Incorporating Diffracting Structure and Method of Fabricating Them Field of the Invention This invention relates to a light diffracting structure and to an authenticating pattern especially for use in an authentication label for authenticating and protecting against forgery various valuable objects such as bank notes , credit cards , identification documents , authentication master plates , brand products or phonographic records .
It also relates to a process for fabricating the diffraction structure, the authenticating pattern and the authentication label.
Background of the Invention Sealing is a technique as old as civilization. It identifies the owner and indicates the integrity of an object . A written message becomes a document due to a sealing process .
Today, sealing and printing techniques are used to avoid unauthorized replication of mass produced objects. However, an increasing economic dam:~ge results from forgery due to insufficient security. Security of the sealing process requires that a seal cannot be copied and that the seal stamper or printing plate are held. under control.
Removal of the seal should lead to its destruction when protection against transfer of seals is needed.
A complex engraved pattern is required to protect against forgery.
Nevertheless, every structure created by human beings can be replicated with the necessary skill, information , equipment and time . Typically , the effort to recreate a seal stamper or printing plate will be similar or less than the effort for the production of the original.
This has lead to an ever increasing complexity of the sealing process for valuable objects . Holograms can be used as an additional protection .
For authenticating documents and things US Patent 5,145,212 teaches the use of non-continuous reflective holograms or diffraction gratings . Such a hologram or diffraction grating is firmly attached to a surface that contains visual information desired to be protected from alteration . The reflective discontinuous hologram is formed in a pattern that both permits viewing the protected information through it and the viewing of an authenticating image or other light pattern reconstructed from it in reflection . In another specific authentication application of this US Patent a non-transparent structure of two side-by-side non-continuous holograms or diffraction patterns, each reconstructing a separate image or other light pattern , inc:reases the difficulty of counterfeiting the structure .
PCT application W087/07034 describes holograms , including diffraction gratings , that reconstruct an image which changes as the hologram is tilted with respect to the viewer and in a manner that images reconstructed from copies made of the hologram in monochromatic light do not have that motion .
In UK Patent Application GB 2 093 404 sheet material items which are subject to counterfeiting have an integral or bonded authenticating device which comprises a substrate having a reflective diffractive structure formed as a relief pattern on a viewable surface thereon and a transparent material covering the structure .
Specified grating parameters of the diffractive structure result in peculiar , but easily discernable , optical colour properties that cannot be copied by colour copying machines .
US Patent 4,661,983 describes a random-pattern of microscopic lines or cracks having widths in the order of micrometers that inherently forms in a. dielectric coating layer of an authenticating device incorporated in a secure document . It permits identification of a genuine individual document by comparing read-out line-position information derived by microscopic inspection with read-out digital codes of line-information obtained earlier at the time of fabrication of the document.
It also relates to a process for fabricating the diffraction structure, the authenticating pattern and the authentication label.
Background of the Invention Sealing is a technique as old as civilization. It identifies the owner and indicates the integrity of an object . A written message becomes a document due to a sealing process .
Today, sealing and printing techniques are used to avoid unauthorized replication of mass produced objects. However, an increasing economic dam:~ge results from forgery due to insufficient security. Security of the sealing process requires that a seal cannot be copied and that the seal stamper or printing plate are held. under control.
Removal of the seal should lead to its destruction when protection against transfer of seals is needed.
A complex engraved pattern is required to protect against forgery.
Nevertheless, every structure created by human beings can be replicated with the necessary skill, information , equipment and time . Typically , the effort to recreate a seal stamper or printing plate will be similar or less than the effort for the production of the original.
This has lead to an ever increasing complexity of the sealing process for valuable objects . Holograms can be used as an additional protection .
For authenticating documents and things US Patent 5,145,212 teaches the use of non-continuous reflective holograms or diffraction gratings . Such a hologram or diffraction grating is firmly attached to a surface that contains visual information desired to be protected from alteration . The reflective discontinuous hologram is formed in a pattern that both permits viewing the protected information through it and the viewing of an authenticating image or other light pattern reconstructed from it in reflection . In another specific authentication application of this US Patent a non-transparent structure of two side-by-side non-continuous holograms or diffraction patterns, each reconstructing a separate image or other light pattern , inc:reases the difficulty of counterfeiting the structure .
PCT application W087/07034 describes holograms , including diffraction gratings , that reconstruct an image which changes as the hologram is tilted with respect to the viewer and in a manner that images reconstructed from copies made of the hologram in monochromatic light do not have that motion .
In UK Patent Application GB 2 093 404 sheet material items which are subject to counterfeiting have an integral or bonded authenticating device which comprises a substrate having a reflective diffractive structure formed as a relief pattern on a viewable surface thereon and a transparent material covering the structure .
Specified grating parameters of the diffractive structure result in peculiar , but easily discernable , optical colour properties that cannot be copied by colour copying machines .
US Patent 4,661,983 describes a random-pattern of microscopic lines or cracks having widths in the order of micrometers that inherently forms in a. dielectric coating layer of an authenticating device incorporated in a secure document . It permits identification of a genuine individual document by comparing read-out line-position information derived by microscopic inspection with read-out digital codes of line-information obtained earlier at the time of fabrication of the document.
The digital data of the random cracks being stored after microscopically inspecting the document these data are used for the fabrication of cracks if the random pattern does not inherently develop .
Although these examples make forging more difficult , they can give no absolute protection . The digital data may be copied and the hologram information may be copied photographically or the hologram may be recreated . Minor deviations of holograms cannot be determined easily, as the extended non-monochromatic illumination within a real-world environment tends to reproduce hologram images with fuzzy shapes and colours.
Summary of the Invention It is therefore an object of the present invention to provide a light diffracting structure, an authenticating pattern and an authentication. label with perceivable parameters where it is difficult to directly copy or to recreate t;he diffraction structure , the pattern or the label.
A light diffracting structure has unique parameters generating a uniquely coloured pattern. The unique parameters are randomly defined by a:nisotropic process steps during the manufacturing of the diffracting structure .
An authenticating pattern comprises an integrated structure of a substrate layer and a transparent overcoat layer and the viewable interface therebetween includes a light diffracting structure .
An authentication label comprises at least one authenticating pattern and personalizing information like pictorial or alphanumeric information or any combination thereof .
An authenticating pattern or an authentication label incorporating a diffracting structure with randomly defined parameters is not under full control of the producer .
Therefore not even the producer or owner of an original authenticating pattern can copy it or create an exact replica thereof . The uniquely coloured authenticating pattern can be verified by simple observation with the naked eye and thus simplifies the recognition by making use of the unsurpassed image processing properties of the human eye. This visual access to an authenticating pattern or an authentication label without a special illumination or equipment is a prerequisite for ubiquitous verification.
Forgery of money causes significant economic loss . The advent of high quality copy machines severely threatens many currencies .
Identification documents like passports, identity cards or drivers licenses are used for different purposes, also for governmentally regulated purposes.
Credit cards or corporate badges identify the owner of an account or the employee of a company. In all these cases the document must combine information of the bearer with the authorization information from the issuing organization. An authentication label with personalization on identification documents helps to eliminate the risk to accept an invalid document and with the invention as claimed a machine-based verification is not necessary.
The protection of brand labels has long been a problem. Distribution packages for computer software, in particular, are highly threatened by forgery as the costs for the replication of the package, for example a CD-ROM, are low in comparison with the value of the copied data. An authenticating pattern or authentification label on the data carrier would allow the customer to purchase authorized products and it would allow him to prove the ownership at a legally fabricated product. If all the products of a class or brand were marketed with a personalized authentificating pattern or authentification label, the ownership claim for a stolen object like e. g. an automobile can be verified from an intact pattern or label. A missing pattern or label would indicate manipulation. The exchange of an authentificating pattern or authentification label would not make sense as it requires the possession of an identical product .
Although these examples make forging more difficult , they can give no absolute protection . The digital data may be copied and the hologram information may be copied photographically or the hologram may be recreated . Minor deviations of holograms cannot be determined easily, as the extended non-monochromatic illumination within a real-world environment tends to reproduce hologram images with fuzzy shapes and colours.
Summary of the Invention It is therefore an object of the present invention to provide a light diffracting structure, an authenticating pattern and an authentication. label with perceivable parameters where it is difficult to directly copy or to recreate t;he diffraction structure , the pattern or the label.
A light diffracting structure has unique parameters generating a uniquely coloured pattern. The unique parameters are randomly defined by a:nisotropic process steps during the manufacturing of the diffracting structure .
An authenticating pattern comprises an integrated structure of a substrate layer and a transparent overcoat layer and the viewable interface therebetween includes a light diffracting structure .
An authentication label comprises at least one authenticating pattern and personalizing information like pictorial or alphanumeric information or any combination thereof .
An authenticating pattern or an authentication label incorporating a diffracting structure with randomly defined parameters is not under full control of the producer .
Therefore not even the producer or owner of an original authenticating pattern can copy it or create an exact replica thereof . The uniquely coloured authenticating pattern can be verified by simple observation with the naked eye and thus simplifies the recognition by making use of the unsurpassed image processing properties of the human eye. This visual access to an authenticating pattern or an authentication label without a special illumination or equipment is a prerequisite for ubiquitous verification.
Forgery of money causes significant economic loss . The advent of high quality copy machines severely threatens many currencies .
Identification documents like passports, identity cards or drivers licenses are used for different purposes, also for governmentally regulated purposes.
Credit cards or corporate badges identify the owner of an account or the employee of a company. In all these cases the document must combine information of the bearer with the authorization information from the issuing organization. An authentication label with personalization on identification documents helps to eliminate the risk to accept an invalid document and with the invention as claimed a machine-based verification is not necessary.
The protection of brand labels has long been a problem. Distribution packages for computer software, in particular, are highly threatened by forgery as the costs for the replication of the package, for example a CD-ROM, are low in comparison with the value of the copied data. An authenticating pattern or authentification label on the data carrier would allow the customer to purchase authorized products and it would allow him to prove the ownership at a legally fabricated product. If all the products of a class or brand were marketed with a personalized authentificating pattern or authentification label, the ownership claim for a stolen object like e. g. an automobile can be verified from an intact pattern or label. A missing pattern or label would indicate manipulation. The exchange of an authentificating pattern or authentification label would not make sense as it requires the possession of an identical product .
A unique pattern or label embedded into a write-once or read-only type data carrier allows to prove the integrity of large sets of coded data. With a reference to the authentificating pattern code or to the authentification label code stored with the data, it is not possible to copy modified data onto an identical data carrier .
Attempts to modify data on the original carrier makes no sense as it affects e.g.
checksums and other criteria. A forge-proof authentificating pattern or authentification label allows the use of large encoded databases like catasters , patent data bases or financial files as legally approved documents .
All these examples show that equippped with the authenticating pattern or the authentication label objects like money bills , passports , credit cards etc .
gain maximum protection against forgery .
In one aspect of the present invention there is provided a light diffracting structure having unique parameters which , when exposed to light , generate a unique colour pattern, said unique parameters randomly defined by anisotropic grooves, said anisotropic grooves having varying depths and widths .
In a further aspect of the invention there is provided an authenticating pattern comprising an integrated structure of a substrate layer and. a transparent overcoat layer , and a viewable interface therebetween including a light diffracting structure .
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure comprising providing a substrate layer, depositing a photoresistlayer on said substrate layer, transferring a mask pattern onto said photoresist layer , using the patterned photoresist layer as a mask for etching pits into said substrate layer in a way to provide an anisotropic etching characteristic, wherein etching said pits into said substrate layer comprises one of wet etching, and photochemical etching with variable illumination ; and removing said photoresist layer .
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure comprising providing a substrate , rex>licating a pattern of a diffracting structure into the substrate by stamping or molding processes using the diffracting structure as a master plate, wherein the extent of parameter variations of said authenticating pattern caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic process steps during the manufacturing of said diffracting structure and depositing an overcoat layer on said patterned substrate wherein said overcoat layer fills pits .
In a further aspect of the invention there is provided a light diffracting structure having parameters generating a visibly distinguishable colored pattern that is used to validate the authenticity of an object attached to the structure wherein said parameters are randomly defined by anisotropic process steps during the manufacturing of said diffracting structure .
In a further aspect of the invention there is provided an authenticating pattern for an object comprising an integrated structure of a substrate layer and a transparent overcoat layer formed on the object, the layers defining a viewable interface therebetween including a light diffracting structure randomly defined by anisotropic steps during the manufacture of the diffracting structure to produce a visibly distinguishable colored pattern that is used to validate the authenticity of the object.
In a further aspect of the invention there is provided an authentication label as part of an object comprising (a) an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic process during the manufacture of the diffracting structure to produce a visibly identifiable authenticating pattern, and (b) graphic personalication information formed in said integrated structure .
In a further aspect of the invention there is provided a method of providing an authenticating pattern for an object comprising forming an integrated structure of a substrate layer and a transparent overcoat layer on the object so that the layers define a viewable interface therebetween that includes a light diffracaing structure randomly 5a defined by an anisotropic etching process involving photochemical etching with variable illumination that causes random variations in peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce a colored pattern visibly distinguishable by the naked human eye without special lighting or equipment to validate the authenticity of the object.
In a further aspect of the invention there is provided a method of providing an authentication label as part of an object comprising ( a ) forming an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic etching process involving photochemical etching with variable illumination that causes random variation in the peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce a.n authenticating pattern visibly identifiable by the naked eye without special illumination , and ( b ) forming graphic personalization information in said integrated structure.
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure used for authentication purposes comprising providing data for a pattern of a light diffracting pattern structure , and using an anisotropic photochemical etching process to manufacture said light diffracting structure from the data, said process involving photochemical etching with variable illumination that causes random variation in peak-to-valley ratios a:b and line depths c of the light diffracting structure to provide a randomly defined colored pattern visibly distinguishable from other patterns by the naked eye without the use of special lighting for validating the authenticity of an object attached to the structure.
In a further aspect of the invention there is provided a method of fabricating an authenticating label for an object comprising providing data for a pattern of a light diffracting structure , using an anisotropic process involving photochemical etching with variable lighting that causes random variations in peak-to-valley ratios a: b and line depth c to manufacture a master of the light diffracting structure with random variations in the pattern which variations provide a color pattern visibly distinguishable 5b by the naked human eye without special illumination or equipment , replicating the diffracting structure using the master, and covering the r~eplic;~ted diffracting structure with an overcoat layer.
In a further aspect of the invention there is provided a method of providing an authenticating pattern for objects comprising providing a randomly occurring condition in an anisotropic etching step during the forming of a diffracting structure in a substrate layer to produce a visibly distinguishable colored pattern that is used to validate the authenticity of an object, wherein said randomly occurring condition is produced by subjecting the substrate layer to randomly varying light during photochemical etching of the light diffracting structure .
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure used for authentication purposes comprising providing data for a pattern of a light diffracting structure , using an anisotropic etching process to fabricate the light diffracting structure from the data, and inserting a randomly occurring condition in the anisotropic etching process so that the light diffracting structure produces a unique colored pattern visibly distinguishable from other patterns in natural light by the naked eye so that the colored pattern <:an be used in validating the authenticity of an object attached to the structure.
In a further aspect of the invention there is provided a method of fabricating an authenticating label for an object comprising providing data for a pattern of a light diffracting structure, inserting a randomly occurring condition in an anisotropic process used to manufacture a master of a light diffracting structure to cause random variations in the pattern defined by the data which variations provide a unique color pattern visibly distinguishable by the naked human eye without special illumination or equipment includes providing a substrate layer, depositing a photoresist; layer on said substrate layer , providing a mask pattern defined by said data into said photoresist layer , anisotropically etching pits defined by the mask pattern into said substrate layer by photochemical etching with variable illumination , and removing said photoresist layer , replicating the diffracting structure using the master , and covering the replicated 5c diffracting structure with an overcoat layer .
Master plates of the authenticating pattern testify the authorization of the label manufacturer .
Brief Description of the Drawings Ways of carrying out the invention are described in detail below with reference to drawings showing only specific embodiments in which Fig .1 schematically shows an embodiment of a light diffracting structure in form of a relief grating with some of the most important parameters ;
Fig . 2a shows a prior art example of a diffraction pattern or diffraction grating of a hologram and Fig.2b illustrates characteristic curves of the diffraction pattern of Fig . 2a ;
Fig.3 is a schematic diagram of an authenticating pattern with the light diffracting structure of Fig .1;
Figs.4a, 4b and 4c schematically illustrate embodiments of an authentication label 5d with the authenticating pattern of Fig . 3 ;
Figs.Sa, 5b and 5c show different objects equipped with an authentication label; and Fig.6 schematically illustrates a possible method for quantifying the colour of the authentication label.
Detailed Description The light diffracting structure shown in Fig. 1 is a relief grating 10 with numerous grooves or pits which may have the same or different groove or line depths c .
Another important parameter of the diffracting structure 10 is the peak-to-valley ratio b:a.
An optical phase grating like the relief grating of Fig .1 reflects incident light into various diffraction orders depending on the wavelength of the light , the grid line density, the grid depth which is the line depth c and the grid line profile or grid line anisotropy which is the peak-to-valley ratio b:a.
The diffraction colour varies strongly with the line depth c . This is shown in the prior art diffraction grating of hologram 29' of Fig.2a with three adjacent grating regions 47' , 49' and 51' . In this example the area 47' is constructed to have a groove depth which is substantially that indicated at D3 in Fig . 2b . The amount of light diffracted from that area into a blue component of the first order diffracted beam is zero , while there is some intensity in other colours. Similarly, the adjacent area 49' is made to have a groove depth substantially equal to D4 indicated in Fig.2b, thus having no light diffracted in the green portion . Lastly , the region 51' is made to have a groove depth substantially equal to D5 of Fig.2b, thereby having substantially no intensity diffracted into the red component of the first order diffracted beam .
The diffraction colours representable by the diffraction structure 10 can be used to design the authenticating patterns 30 of Figs . 4a - 4c that contain colour field information. By design these colours may only be roughly determined, there are no ~~~ 3~~~
"correct" colours and there is no fuzziness due to imperfect replication.
Variations in the line depth c of some 10 nm can be observed easily and an even higher sensitivity of about 5 nm can be achieved when the visibility of the borderline between two similar grating regions, areas or colour fields is judged.
The saturation of the diffraction colours depends on the peak-to-valley ratio b : a of the diffracting structure 10. It gives a highly sensitive colour field discrimination criterion. The visual deviation of a nominally diffracting structure 10 depends exclusively on the non-linearity of the manufacturing process .
The relative intensity of the diffraction colours depends on the grid profile and the surface roughness or micro-roughness . The grid profile comprises a widespread variety of different shaped gridlines like rectangular gridlines or gridlines with rounded corners .
Instead of a relief grating as shown in Fig. 1 the diffracting structure may be an arrangement of periodic areal structure elements .
The authenticating pattern 20 of Fig. 3 is an integrated structure of a substrate layer 21 and an overcoat layer 22.
The interface between substrate layer 21 and overcoat layer 22 is viewable and includes the light diffracting structure 10. If the overcoat layer 22 covering the relief grating 10 is transparent, light diffracted at angles above some 45 degrees may be caught within the overcoat layer 22 due to total internal reflection as indicated in Fig . 3, right side .
For a grid or relief grating with more than approximately 2000 lines/mm already the first order diffraction will be caught . This high line density assures total internal reflectance within the overcoat layer 22. In this case the specularly reflected light appears in the interference colour that is defined by the line depth c of the relief grating or grid .
The material of the substrate layer 21 and the overcoat layer 22 comprises transparent amorphous materials like polymers, resins and artificial resins which may also be coloured.
The transparent overcoat layer 22 is bonded to said substrate layer 21 in a manner sufficiently secure to prevent said overcoat layer 22 from being removed from said substrate layer 21 without destroying said substrate layer.
The integrated structure may comprise a metal layer overcoating said diffracting structure . Especially in the fabrication of compact disks a metal layer may be applied for high reflectance. The metallization layer may be homogeneous or made from randomly sputtered metal particles A bonding layer will provide the interface between the authenticating pattern or authentification label containing one or a plurality of the integrated structures and the object to be protected .
If the metallization layer is not homogeneous and if the material of the overcoat layer 22 and the bonding layer is identical, it will be impossible to free the relief surface within the 10 nm tolerance .
Alternatively, the relief grating may be filled with a transparent material with different refractive index. This would further impede the mechanical access to the undistorted relief. In this embodiment a flat metal coating may be added.
Figs . 4a to 4c show various kinds of authentication labels 30 with authenticating patterns or colour fields 20 of Fig.3. The authentication labels 30 consist of at least one authenticating pattern 20 or a distinct number of authenticating patterns allowing several different kinds of geometrical arrangements and additional personalizing information 31.
Attempts to modify data on the original carrier makes no sense as it affects e.g.
checksums and other criteria. A forge-proof authentificating pattern or authentification label allows the use of large encoded databases like catasters , patent data bases or financial files as legally approved documents .
All these examples show that equippped with the authenticating pattern or the authentication label objects like money bills , passports , credit cards etc .
gain maximum protection against forgery .
In one aspect of the present invention there is provided a light diffracting structure having unique parameters which , when exposed to light , generate a unique colour pattern, said unique parameters randomly defined by anisotropic grooves, said anisotropic grooves having varying depths and widths .
In a further aspect of the invention there is provided an authenticating pattern comprising an integrated structure of a substrate layer and. a transparent overcoat layer , and a viewable interface therebetween including a light diffracting structure .
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure comprising providing a substrate layer, depositing a photoresistlayer on said substrate layer, transferring a mask pattern onto said photoresist layer , using the patterned photoresist layer as a mask for etching pits into said substrate layer in a way to provide an anisotropic etching characteristic, wherein etching said pits into said substrate layer comprises one of wet etching, and photochemical etching with variable illumination ; and removing said photoresist layer .
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure comprising providing a substrate , rex>licating a pattern of a diffracting structure into the substrate by stamping or molding processes using the diffracting structure as a master plate, wherein the extent of parameter variations of said authenticating pattern caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic process steps during the manufacturing of said diffracting structure and depositing an overcoat layer on said patterned substrate wherein said overcoat layer fills pits .
In a further aspect of the invention there is provided a light diffracting structure having parameters generating a visibly distinguishable colored pattern that is used to validate the authenticity of an object attached to the structure wherein said parameters are randomly defined by anisotropic process steps during the manufacturing of said diffracting structure .
In a further aspect of the invention there is provided an authenticating pattern for an object comprising an integrated structure of a substrate layer and a transparent overcoat layer formed on the object, the layers defining a viewable interface therebetween including a light diffracting structure randomly defined by anisotropic steps during the manufacture of the diffracting structure to produce a visibly distinguishable colored pattern that is used to validate the authenticity of the object.
In a further aspect of the invention there is provided an authentication label as part of an object comprising (a) an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic process during the manufacture of the diffracting structure to produce a visibly identifiable authenticating pattern, and (b) graphic personalication information formed in said integrated structure .
In a further aspect of the invention there is provided a method of providing an authenticating pattern for an object comprising forming an integrated structure of a substrate layer and a transparent overcoat layer on the object so that the layers define a viewable interface therebetween that includes a light diffracaing structure randomly 5a defined by an anisotropic etching process involving photochemical etching with variable illumination that causes random variations in peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce a colored pattern visibly distinguishable by the naked human eye without special lighting or equipment to validate the authenticity of the object.
In a further aspect of the invention there is provided a method of providing an authentication label as part of an object comprising ( a ) forming an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic etching process involving photochemical etching with variable illumination that causes random variation in the peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce a.n authenticating pattern visibly identifiable by the naked eye without special illumination , and ( b ) forming graphic personalization information in said integrated structure.
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure used for authentication purposes comprising providing data for a pattern of a light diffracting pattern structure , and using an anisotropic photochemical etching process to manufacture said light diffracting structure from the data, said process involving photochemical etching with variable illumination that causes random variation in peak-to-valley ratios a:b and line depths c of the light diffracting structure to provide a randomly defined colored pattern visibly distinguishable from other patterns by the naked eye without the use of special lighting for validating the authenticity of an object attached to the structure.
In a further aspect of the invention there is provided a method of fabricating an authenticating label for an object comprising providing data for a pattern of a light diffracting structure , using an anisotropic process involving photochemical etching with variable lighting that causes random variations in peak-to-valley ratios a: b and line depth c to manufacture a master of the light diffracting structure with random variations in the pattern which variations provide a color pattern visibly distinguishable 5b by the naked human eye without special illumination or equipment , replicating the diffracting structure using the master, and covering the r~eplic;~ted diffracting structure with an overcoat layer.
In a further aspect of the invention there is provided a method of providing an authenticating pattern for objects comprising providing a randomly occurring condition in an anisotropic etching step during the forming of a diffracting structure in a substrate layer to produce a visibly distinguishable colored pattern that is used to validate the authenticity of an object, wherein said randomly occurring condition is produced by subjecting the substrate layer to randomly varying light during photochemical etching of the light diffracting structure .
In a further aspect of the invention there is provided a method of fabricating a light diffracting structure used for authentication purposes comprising providing data for a pattern of a light diffracting structure , using an anisotropic etching process to fabricate the light diffracting structure from the data, and inserting a randomly occurring condition in the anisotropic etching process so that the light diffracting structure produces a unique colored pattern visibly distinguishable from other patterns in natural light by the naked eye so that the colored pattern <:an be used in validating the authenticity of an object attached to the structure.
In a further aspect of the invention there is provided a method of fabricating an authenticating label for an object comprising providing data for a pattern of a light diffracting structure, inserting a randomly occurring condition in an anisotropic process used to manufacture a master of a light diffracting structure to cause random variations in the pattern defined by the data which variations provide a unique color pattern visibly distinguishable by the naked human eye without special illumination or equipment includes providing a substrate layer, depositing a photoresist; layer on said substrate layer , providing a mask pattern defined by said data into said photoresist layer , anisotropically etching pits defined by the mask pattern into said substrate layer by photochemical etching with variable illumination , and removing said photoresist layer , replicating the diffracting structure using the master , and covering the replicated 5c diffracting structure with an overcoat layer .
Master plates of the authenticating pattern testify the authorization of the label manufacturer .
Brief Description of the Drawings Ways of carrying out the invention are described in detail below with reference to drawings showing only specific embodiments in which Fig .1 schematically shows an embodiment of a light diffracting structure in form of a relief grating with some of the most important parameters ;
Fig . 2a shows a prior art example of a diffraction pattern or diffraction grating of a hologram and Fig.2b illustrates characteristic curves of the diffraction pattern of Fig . 2a ;
Fig.3 is a schematic diagram of an authenticating pattern with the light diffracting structure of Fig .1;
Figs.4a, 4b and 4c schematically illustrate embodiments of an authentication label 5d with the authenticating pattern of Fig . 3 ;
Figs.Sa, 5b and 5c show different objects equipped with an authentication label; and Fig.6 schematically illustrates a possible method for quantifying the colour of the authentication label.
Detailed Description The light diffracting structure shown in Fig. 1 is a relief grating 10 with numerous grooves or pits which may have the same or different groove or line depths c .
Another important parameter of the diffracting structure 10 is the peak-to-valley ratio b:a.
An optical phase grating like the relief grating of Fig .1 reflects incident light into various diffraction orders depending on the wavelength of the light , the grid line density, the grid depth which is the line depth c and the grid line profile or grid line anisotropy which is the peak-to-valley ratio b:a.
The diffraction colour varies strongly with the line depth c . This is shown in the prior art diffraction grating of hologram 29' of Fig.2a with three adjacent grating regions 47' , 49' and 51' . In this example the area 47' is constructed to have a groove depth which is substantially that indicated at D3 in Fig . 2b . The amount of light diffracted from that area into a blue component of the first order diffracted beam is zero , while there is some intensity in other colours. Similarly, the adjacent area 49' is made to have a groove depth substantially equal to D4 indicated in Fig.2b, thus having no light diffracted in the green portion . Lastly , the region 51' is made to have a groove depth substantially equal to D5 of Fig.2b, thereby having substantially no intensity diffracted into the red component of the first order diffracted beam .
The diffraction colours representable by the diffraction structure 10 can be used to design the authenticating patterns 30 of Figs . 4a - 4c that contain colour field information. By design these colours may only be roughly determined, there are no ~~~ 3~~~
"correct" colours and there is no fuzziness due to imperfect replication.
Variations in the line depth c of some 10 nm can be observed easily and an even higher sensitivity of about 5 nm can be achieved when the visibility of the borderline between two similar grating regions, areas or colour fields is judged.
The saturation of the diffraction colours depends on the peak-to-valley ratio b : a of the diffracting structure 10. It gives a highly sensitive colour field discrimination criterion. The visual deviation of a nominally diffracting structure 10 depends exclusively on the non-linearity of the manufacturing process .
The relative intensity of the diffraction colours depends on the grid profile and the surface roughness or micro-roughness . The grid profile comprises a widespread variety of different shaped gridlines like rectangular gridlines or gridlines with rounded corners .
Instead of a relief grating as shown in Fig. 1 the diffracting structure may be an arrangement of periodic areal structure elements .
The authenticating pattern 20 of Fig. 3 is an integrated structure of a substrate layer 21 and an overcoat layer 22.
The interface between substrate layer 21 and overcoat layer 22 is viewable and includes the light diffracting structure 10. If the overcoat layer 22 covering the relief grating 10 is transparent, light diffracted at angles above some 45 degrees may be caught within the overcoat layer 22 due to total internal reflection as indicated in Fig . 3, right side .
For a grid or relief grating with more than approximately 2000 lines/mm already the first order diffraction will be caught . This high line density assures total internal reflectance within the overcoat layer 22. In this case the specularly reflected light appears in the interference colour that is defined by the line depth c of the relief grating or grid .
The material of the substrate layer 21 and the overcoat layer 22 comprises transparent amorphous materials like polymers, resins and artificial resins which may also be coloured.
The transparent overcoat layer 22 is bonded to said substrate layer 21 in a manner sufficiently secure to prevent said overcoat layer 22 from being removed from said substrate layer 21 without destroying said substrate layer.
The integrated structure may comprise a metal layer overcoating said diffracting structure . Especially in the fabrication of compact disks a metal layer may be applied for high reflectance. The metallization layer may be homogeneous or made from randomly sputtered metal particles A bonding layer will provide the interface between the authenticating pattern or authentification label containing one or a plurality of the integrated structures and the object to be protected .
If the metallization layer is not homogeneous and if the material of the overcoat layer 22 and the bonding layer is identical, it will be impossible to free the relief surface within the 10 nm tolerance .
Alternatively, the relief grating may be filled with a transparent material with different refractive index. This would further impede the mechanical access to the undistorted relief. In this embodiment a flat metal coating may be added.
Figs . 4a to 4c show various kinds of authentication labels 30 with authenticating patterns or colour fields 20 of Fig.3. The authentication labels 30 consist of at least one authenticating pattern 20 or a distinct number of authenticating patterns allowing several different kinds of geometrical arrangements and additional personalizing information 31.
~1~~~~~
The authenticating patterns may be combined to form bigger uniform colour fields or fields with colour gradients . Regular geometrical arrangements help to memorize the colour shade crossover locations . From the locations of characteristic shades a code number may be derived and this number may be memorized or communicated with ease .
A possible method for quantifying the colour of the authentication label is indicated in Fig. 6. This method uses the fact that the saturation of the diffraction colours depends on the peak-to-valley ratio b : a of the diffracting structure 10 .
Varying the peak-to-valley ratio continuously within a relief structure 60 enhances the colour contrast until maximum colour saturation is reached as shown by the colour saturation curve 61. Using two relief structures with the peak-to-valley variation to reach maximum contrast running into opposite directions and two scales 62 easily allows to define an equality mark 63 which represents a quantitative size.
A system based on this effect would allow the translation of random colours and shades into a numeric code that allows quantitative pattern classification.
The personalizing information comprises pictorial or alphanumeric information and /or holograms or holographic elements or any combination thereof . A logo of the issuing authority could easily be incorporated which facilitates the memorizing of the colour pattern .
The authentication label offers a great variety of different possible shapes .
In the embodiments shown in Figs . 4a to 4b the authentification label 30 is substantially circular in shape and the authenticating patterns 20 are concentrically arranged around the personalizing information 31 provided in the center of the circle.
A
substantially circular or rounded shape complicates or impedes the peeling from the objects equipped with an authentication label.
Although it is virtually impossible that the colour parameters match accurately for a multitude of colour fields within an authenticating pattern 30 shown in Figs . 4a - 4c , there are more parameters that depend on the diffractive structure.
A macro-roughness superimposed over the grid pattern may be modulated to produce areas in the surface of the diffractive structure varying between specular and diffuse reflexion . In the areas of specular reflexion the line depth c is nearly zero and there are no diffraction colours to be observed . Specular reflectance and diffuse scatter can be judged independently by comparison with areas or fields of pure specular reflectance or pure scatter .
The polarization state of the light reflected from the authenticating pattern 20 results from the interaction of the diffractive structure 10 and the overcoat layer 22. It is wavelength dependent .
The shape of the gridlines and their anisotropy affects the appearance of the diffracted light that leaves the overcoat layer 22 without total reflexion as indicated in Fig . 3 , right side .
An appropriate design allows to prepare colour fields 20 that exhibit characteristic colour changes as a function of the two tilt angles .
The selection of the grid line direction allows to steer the diffraction pattern individually for every location on the authenticating pattern .
The characteristic absorption of the overcoat layer 22 as a function of the wavelength affects the fate of the totally reflected light . The variation of the colour with the incidence angle depends on the refractive index of the overcoat layer .
The influence of the refractive index and the characteristic absorption of the overcoat layer material restricts the options to use alternative materials for a copy.The superposition of a number of different grid structures allows arbitrary combinations of colour effects .
~~.~3~~
Some possible objects, especially credit cards and identification cards, which could be equipped with an authentication label 30 are shown in Figs. 5a to 5c.
Various other valuable objects such as bank notes, identification documents, authentication master plates, brand products or phonographic records could also be equipped with one or more of the authentication labels described above.
Methods for producing a diffracting structure or a master plate will now be described in detail.
To generate the light diffracting structure 10 with high structure density, the manufacturing technology for advanced semiconductor products can be adapted.
A mask for the horizontal pattern of the light diffracting structure may be generated from computer data. On a substrate a layer of photoresist is deposited and the mask pattern is then transferred into the photoresist layer. After development the patterned resist layer is used as a mask during the step of etching pits or grooves into the substrate. The etch depth defining the line depth c of the relief grating 10 also depends on the size of the apertures in the photoresist. Various techniques are available to obtain an anisotropic etching characteristic, like wet etching and photochemical etching. With photochemical etching the etch depth may be affected by a locally variable illumination. After the etching step being completed the patterned photoresist layer is removed.
To obtain the authenticating pattern 20 an overcoat layer 22 is deposited on the substrate and fills the pits.
The diffracting structure 10 obtained as described above may also be used as a master plate for generating numerous identical authenticating patterns 20. To achieve this, the pattern of the diffracting structure is replicated in a substrate by stamping or molding processes using the diffracting structure 10 as a master plate.
The substrate typically is of transparent polymeric material. For individualization rr 2I~~3~~
additional information may be written into the molded relief by laser burning or other known techniques . The extent of parameter variations of said authenticating patterns caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic etching process step during the manufacturing of the diffracting structure 10.
An additional effect preventing copying is the shrinking of material after the molding process . The shrinking smoothens the relief grating 10 and even if a copy of the relief structure were possible, the preparation of a new master plate would require an unshrinking and a relief-sharpening process. This seems not feasible.
Submaster plates for generating authentication patterns may be produced from the master plate by well-known replication techniques . The submaster plate should obtain a personalization pattern to prevent the production of another master plate .
The personalization may contain additional self-encoded information. This allows to verify both the authenticity of the diffracting structure as a master plate and the descendence from the master plate.
To complete the authenticating pattern 20 an overcoat layer 22 is deposited on the substrate 21 and fills the pits. Additional personalizing information like pictorial or alphanumeric information or any combination thereof is added to the substrate layer 21 or to the overcoat layer 22 or to both of them. The personalizing information may be written into said layers by laser burning, by stamping or by molding processes .
According to the manufacturing methods described above with their random process steps unique authenticating patterns or authentification labels may be created with perceivable random variation of the pattern or label. The random variation is large as compared to the statistical variations during the replication processes like stamping or molding and the randomization space is too big for a systematic experimental recreation. All this avoids an authenticating pattern or an authentication label of the invention being copied directly or to produce a master plate from the pattern or label.
The authenticating patterns may be combined to form bigger uniform colour fields or fields with colour gradients . Regular geometrical arrangements help to memorize the colour shade crossover locations . From the locations of characteristic shades a code number may be derived and this number may be memorized or communicated with ease .
A possible method for quantifying the colour of the authentication label is indicated in Fig. 6. This method uses the fact that the saturation of the diffraction colours depends on the peak-to-valley ratio b : a of the diffracting structure 10 .
Varying the peak-to-valley ratio continuously within a relief structure 60 enhances the colour contrast until maximum colour saturation is reached as shown by the colour saturation curve 61. Using two relief structures with the peak-to-valley variation to reach maximum contrast running into opposite directions and two scales 62 easily allows to define an equality mark 63 which represents a quantitative size.
A system based on this effect would allow the translation of random colours and shades into a numeric code that allows quantitative pattern classification.
The personalizing information comprises pictorial or alphanumeric information and /or holograms or holographic elements or any combination thereof . A logo of the issuing authority could easily be incorporated which facilitates the memorizing of the colour pattern .
The authentication label offers a great variety of different possible shapes .
In the embodiments shown in Figs . 4a to 4b the authentification label 30 is substantially circular in shape and the authenticating patterns 20 are concentrically arranged around the personalizing information 31 provided in the center of the circle.
A
substantially circular or rounded shape complicates or impedes the peeling from the objects equipped with an authentication label.
Although it is virtually impossible that the colour parameters match accurately for a multitude of colour fields within an authenticating pattern 30 shown in Figs . 4a - 4c , there are more parameters that depend on the diffractive structure.
A macro-roughness superimposed over the grid pattern may be modulated to produce areas in the surface of the diffractive structure varying between specular and diffuse reflexion . In the areas of specular reflexion the line depth c is nearly zero and there are no diffraction colours to be observed . Specular reflectance and diffuse scatter can be judged independently by comparison with areas or fields of pure specular reflectance or pure scatter .
The polarization state of the light reflected from the authenticating pattern 20 results from the interaction of the diffractive structure 10 and the overcoat layer 22. It is wavelength dependent .
The shape of the gridlines and their anisotropy affects the appearance of the diffracted light that leaves the overcoat layer 22 without total reflexion as indicated in Fig . 3 , right side .
An appropriate design allows to prepare colour fields 20 that exhibit characteristic colour changes as a function of the two tilt angles .
The selection of the grid line direction allows to steer the diffraction pattern individually for every location on the authenticating pattern .
The characteristic absorption of the overcoat layer 22 as a function of the wavelength affects the fate of the totally reflected light . The variation of the colour with the incidence angle depends on the refractive index of the overcoat layer .
The influence of the refractive index and the characteristic absorption of the overcoat layer material restricts the options to use alternative materials for a copy.The superposition of a number of different grid structures allows arbitrary combinations of colour effects .
~~.~3~~
Some possible objects, especially credit cards and identification cards, which could be equipped with an authentication label 30 are shown in Figs. 5a to 5c.
Various other valuable objects such as bank notes, identification documents, authentication master plates, brand products or phonographic records could also be equipped with one or more of the authentication labels described above.
Methods for producing a diffracting structure or a master plate will now be described in detail.
To generate the light diffracting structure 10 with high structure density, the manufacturing technology for advanced semiconductor products can be adapted.
A mask for the horizontal pattern of the light diffracting structure may be generated from computer data. On a substrate a layer of photoresist is deposited and the mask pattern is then transferred into the photoresist layer. After development the patterned resist layer is used as a mask during the step of etching pits or grooves into the substrate. The etch depth defining the line depth c of the relief grating 10 also depends on the size of the apertures in the photoresist. Various techniques are available to obtain an anisotropic etching characteristic, like wet etching and photochemical etching. With photochemical etching the etch depth may be affected by a locally variable illumination. After the etching step being completed the patterned photoresist layer is removed.
To obtain the authenticating pattern 20 an overcoat layer 22 is deposited on the substrate and fills the pits.
The diffracting structure 10 obtained as described above may also be used as a master plate for generating numerous identical authenticating patterns 20. To achieve this, the pattern of the diffracting structure is replicated in a substrate by stamping or molding processes using the diffracting structure 10 as a master plate.
The substrate typically is of transparent polymeric material. For individualization rr 2I~~3~~
additional information may be written into the molded relief by laser burning or other known techniques . The extent of parameter variations of said authenticating patterns caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic etching process step during the manufacturing of the diffracting structure 10.
An additional effect preventing copying is the shrinking of material after the molding process . The shrinking smoothens the relief grating 10 and even if a copy of the relief structure were possible, the preparation of a new master plate would require an unshrinking and a relief-sharpening process. This seems not feasible.
Submaster plates for generating authentication patterns may be produced from the master plate by well-known replication techniques . The submaster plate should obtain a personalization pattern to prevent the production of another master plate .
The personalization may contain additional self-encoded information. This allows to verify both the authenticity of the diffracting structure as a master plate and the descendence from the master plate.
To complete the authenticating pattern 20 an overcoat layer 22 is deposited on the substrate 21 and fills the pits. Additional personalizing information like pictorial or alphanumeric information or any combination thereof is added to the substrate layer 21 or to the overcoat layer 22 or to both of them. The personalizing information may be written into said layers by laser burning, by stamping or by molding processes .
According to the manufacturing methods described above with their random process steps unique authenticating patterns or authentification labels may be created with perceivable random variation of the pattern or label. The random variation is large as compared to the statistical variations during the replication processes like stamping or molding and the randomization space is too big for a systematic experimental recreation. All this avoids an authenticating pattern or an authentication label of the invention being copied directly or to produce a master plate from the pattern or label.
Claims (76)
1. A light diffracting structure having unique parameters which, when exposted to light, generate a unique coloured pattern, said unique parameters randomly defined by anisotropic grooves, said anisotropic grooves having varying depths and widths.
2. The light diffracting structure of claim 1 wherein said light diffracting structure comprises a structure in form of a relief grating and an arrangement of periodic areal structure elements.
3. The light diffracting structure of claim 1 or 2 wherein said unique parameters comprise a peak-to-valley ratio b:a and a line depth c.
4. An authenticating pattern comprising an integrated structure of a substrate layer and a transparent overcoat layer, a viewable interface therebetween including a light diffracting structure according to any of the preceding claims 1 to 3.
5. The authenticating pattern of claim 4 wherein said light diffracting structure has more than approximately 2000 lines/mm to assure total internal reflectance within said overcoat layer.
6. The authenticating pattern of claim 4 or 5 wherein said transparent overcoat layer is bonded to said substrate layer to prevent said overcoat layer from being removed from said substrate layer without destroying said substrate layer.
7. The authenticating pattern of any of the preceding claims 4 to 6 wherein said integrated structure further comprises a metal layer overcoating said diffracting structure.
8. The authenticating pattern of any of the preceding claims 4 to 7 wherein the material of said substrate layer and said overcoat layer comprises a transparent amorphous material which may also be coloured.
9. The authenticating pattern of claim 8 wherein said amorphous material comprises one or more of polymers, resins and artificial resins.
10. The authenticating pattern of claim 9 wherein said amorphous material is coloured.
11. An authentication label comprising at least one authenticating pattern of any of the preceding claims 4 to 10 and further comprising personalizing information.
12. The authenticating pattern of claim 10 wherein said personalizing information comprises at least one of pictorial, alphanumeric information and any combination thereof.
13. The authentication label of claims 11 or 12 wherein said authentication label is substantially circular in shape and the authenticating patterns are concentrically arranged around the personalizing information provided in the center of the circle.
14. The authentication label of claims 11, 12 or 13 wherein said personalizing information comprises a hologram.
15. A method of fabricating a light diffracting structure comprising:
providing a substrate layer;
depositing a photoresist layer on said substrate layer;
transferring a mask pattern onto said photoresist layer;
using the patterned photoresist layer as a mask for etching pits into said substrate layer in a way to provide an anisotropic etching characteristic, wherein etching said pits into said substrate layer comprises one of wet etching; and photochemical etching with variable illumination ; and removing said photoresist layer.
providing a substrate layer;
depositing a photoresist layer on said substrate layer;
transferring a mask pattern onto said photoresist layer;
using the patterned photoresist layer as a mask for etching pits into said substrate layer in a way to provide an anisotropic etching characteristic, wherein etching said pits into said substrate layer comprises one of wet etching; and photochemical etching with variable illumination ; and removing said photoresist layer.
16. The method of fabricating the light diffracting structure of claim 15 further comprising depositing an overcoat layer on said substrate layer with the pits wherein said overcoat layer fills said pits.
17. A method of fabricating a light diffracting structure comprising:
providing a substrate;
replicating a pattern of a diffracting structure into the substrate by stamping or molding processes using the diffracting structure of any of the preceding claims 1 to 3 as a master plate, wherein the extent of parameter variations of said authenticating pattern caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic process steps during the manufacturing of said diffracting structure and depositing an overcoat layer on said patterned substrate wherein said overcoat layer fills pits.
providing a substrate;
replicating a pattern of a diffracting structure into the substrate by stamping or molding processes using the diffracting structure of any of the preceding claims 1 to 3 as a master plate, wherein the extent of parameter variations of said authenticating pattern caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic process steps during the manufacturing of said diffracting structure and depositing an overcoat layer on said patterned substrate wherein said overcoat layer fills pits.
18. A method of fabricating the authentication label of any of the preceding claims 11 to 14 comprising the steps:
providing at least one authenticating pattern of any of the preceding claims 4 to 10 and adding personalizing information to the substrate layer or to the overcoat layer or to both of them, wherein adding said personalizing information comprises writing said personalizing information into said layers by at least one of laser burning, stamping and molding processes.
providing at least one authenticating pattern of any of the preceding claims 4 to 10 and adding personalizing information to the substrate layer or to the overcoat layer or to both of them, wherein adding said personalizing information comprises writing said personalizing information into said layers by at least one of laser burning, stamping and molding processes.
19. The method of claim 18 wherein the personalizing information comprises one of pictorial, alphanumeric information and any combination thereof.
20. A light diffracting structure having parameters generating a visibly distinguishable colored pattern that is used to validate the authenticity of an object attached to the structure wherein said parameters are randomly defined by anisotropic process steps during the manufacturing of said diffracting structure.
21. The light diffracting structure of claim 20 wherein said light diffracting structure comprises a structure in the form of a relief grating and an arrangement of periodic areal structure elements in the light diffracting structure.
22. The light diffracting structure of claim 21 wherein said parameters comprise the peak-to-valley ratio b:a and the line depth c of the relief grating.
23. An authenticating pattern for an object comprising an integrated structure of a substrate layer and a transparent overcoat layer formed on the object, the layers defining a viewable interface therebetween including a light diffracting structure randomly defined by anisotropic steps during the manufacture of the diffracting structure to produce a visibly distinguishable colored pattern that is used to validate the authenticity of the object.
24. The authenticating pattern of claim 23 wherein said transparent overcoat layer is bonded to said substrate layer in a manner sufficiently secure to prevent said overcoat layer from being removed from said substrate layer without destroying said substrate layer.
25. The light diffracting structure of claim 23 wherein said light diffracting structure includes a structure in the form of a relief grating.
26. The light diffracting structure of claim 25 wherein said parameters comprise the peak-to-valley ratios b:a and the line depths c of the relief grating.
27. An authentication label as part of an object comprising:
a) an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic process during the manufacture of the diffracting structure to produce a visibly identifiable authenticating pattern ; and b) graphic personalization information formed in said integrated structure.
a) an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic process during the manufacture of the diffracting structure to produce a visibly identifiable authenticating pattern ; and b) graphic personalization information formed in said integrated structure.
28 . The authentication label of claim 27, wherein said authentication label is substantially circular in shape and the authenticating patterns are concentrically arranged around the graphic personalizing information provided in the center of the circle.
29. The authentication label of claim 28, wherein said graphic personalizing information comprises a hologram.
30. The authentication label of claim 29, wherein said light diffracting structure includes a relief grating.
31. The authentication label of claim 30, wherein said parameters include the peak-to-valley ratios b:a and the line depths c of the relief grating.
32. The authentication label of claim 31 wherein said light diffracting structure has more than approximate 2000 lines/mm to assure total internal reflectance within said overcoat layer.
33. The authentication label of claim 32 wherein said integrated structure further comprises a metal layer overcoating said diffracting structure.
34. The authentication label of claim 33 wherein the material of said substrate layer and said overcoat layer comprise transparent amorphous materials.
35. The authentication label of claim 27 wherein said graphic personalization information is contained in both said substrate layer and said transparent overcoat.
36. A method of providing an authenticating pattern for an object comprising:
forming an integrated structure of a substrate layer and a transparent overcoat layer on the object so that the layers define a viewable interface therebetween that includes a light diffracting structure randomly defined by an anisotropic etching process involving photochemical etching with variable illumination that causes random variations in peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce a colored pattern visibly distinguishable by the naked human eye without special lighting or equipment to validate the authenticity of the object.
forming an integrated structure of a substrate layer and a transparent overcoat layer on the object so that the layers define a viewable interface therebetween that includes a light diffracting structure randomly defined by an anisotropic etching process involving photochemical etching with variable illumination that causes random variations in peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce a colored pattern visibly distinguishable by the naked human eye without special lighting or equipment to validate the authenticity of the object.
37. The method of claim 36 including using a relief grating and an arrangement of periodic areal structure elements in the light diffracting structure.
38. The method of claim 36 including providing a further substrate, replicating the pattern of the diffracting structure into the further substrate by stamping or molding processes using the diffracting structure of the first mentioned substrate as a master plate, wherein the extent of parameter variations of said authenticating pattern caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic process steps during the manufacturing of said diffracting structure;
and depositing an overcoat layer on said patterned substrate wherein said overcoat layer fills pits in the light diffracting structure.
and depositing an overcoat layer on said patterned substrate wherein said overcoat layer fills pits in the light diffracting structure.
39. The method of claim 38 including adding personalizing information selected from a group consisting of pictorial and alphanumeric information and any combination thereof to the further substrate layer or to the overcoat layer or to both of them, wherein adding said information comprises writing said information into said layers by laser burning.
40. The method of claim 39 including forming said light diffracting structure with more than approximately 2000 lines/mm to assure total internal reflectance within said overcoat layer.
41. The method of claim 40 including bonding said transparent overcoat layer to said substrate layer in a manner sufficiently secure to prevent said overcoat layer from being removed from said substrate layer without destroying said substrate layer.
42. The method of claim 41 including providing a metal layer overcoating for said diffracting structure.
43. The method of claim 42 including using transparent amorphous materials as the material of said substrate layer and said overcoat layer.
44. The method of claim 43 including forming said authentication label in a substantially circular shape with the authenticating patterns concentrically arranged around the graphic personalizing information provided in the center of the circle.
45. The method of claim 44 including using a hologram as said graphic personalizing information.
46. The method of claim 45 including using a relief grating as said light diffracting structure.
47. A method of providing an authentication label as part of an object comprising:
a) forming an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic etching process involving photochemical etching with variable illumination that causes random variation in the peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce an authenticating pattern visibly identifiable by the naked eye without special illumination; and b) forming graphic personalization information in said integrated structure.
a) forming an integrated structure of a substrate layer and a transparent overcoat bonded to the substrate layer to define therebetween a viewable interface including a light diffracting structure randomly produced by an anisotropic etching process involving photochemical etching with variable illumination that causes random variation in the peak-to-valley ratios a:b and line depths c of the light diffracting structure to produce an authenticating pattern visibly identifiable by the naked eye without special illumination; and b) forming graphic personalization information in said integrated structure.
48. The method of claim 47 including providing in said light diffracting structure a structure in the form of a relief grating.
49. The method of claim 47 including providing said graphic personalization information in both said substrate layer and said transparent overcoat.
50. A method of fabricating a light diffracting structure used for authentication purposes comprising:
providing data for a pattern of a light diffracting pattern structure; and using an anisotropic photochemical etching process to manufacture said light diffracting structure from the data, said process involving photochemical etching with variable illumination that causes random variation in peak-to-valley ratios a:b and line depths c of the light diffracting structure to provide a randomly defined colored pattern visibly distinguishable from other patterns by the naked eye without the use of special lighting for validating the authenticity of an object attached to the structure.
providing data for a pattern of a light diffracting pattern structure; and using an anisotropic photochemical etching process to manufacture said light diffracting structure from the data, said process involving photochemical etching with variable illumination that causes random variation in peak-to-valley ratios a:b and line depths c of the light diffracting structure to provide a randomly defined colored pattern visibly distinguishable from other patterns by the naked eye without the use of special lighting for validating the authenticity of an object attached to the structure.
51. A method of fabricating an authenticating label for an object comprising:
providing data for a pattern of a light diffracting structure;
using an anisotropic process involving photochemical etching with variable lighting that causes random variations in peak-to-valley ratios a:b and line depth c to manufacture a master of the light diffracting structure with random variations in the pattern which variations provide a color pattern visibly distinguishable by the naked human eye without special illumination or equipment;
replicating the diffracting structure using the master; and covering the replicated diffracting structure with an overcoat layer.
providing data for a pattern of a light diffracting structure;
using an anisotropic process involving photochemical etching with variable lighting that causes random variations in peak-to-valley ratios a:b and line depth c to manufacture a master of the light diffracting structure with random variations in the pattern which variations provide a color pattern visibly distinguishable by the naked human eye without special illumination or equipment;
replicating the diffracting structure using the master; and covering the replicated diffracting structure with an overcoat layer.
52. The method of claim 51 wherein said anisotropic process includes:
providing a substrate layer;
depositing a photoresist layer on said substrate layer;
providing a mask pattern defined by said data on said photoresist layer;
anisotropically etching pits defined by the mask pattern into said substrate layer by the photochemical etching with variable illumination, and removing said photoresist layer.
providing a substrate layer;
depositing a photoresist layer on said substrate layer;
providing a mask pattern defined by said data on said photoresist layer;
anisotropically etching pits defined by the mask pattern into said substrate layer by the photochemical etching with variable illumination, and removing said photoresist layer.
53. The method of claim 52 wherein the replication of the diffracting structure includes shrinking the replicated structure.
54. The method of claim 53 wherein said replicating involves a molding process.
55. The method of claim 51 wherein the replication of the diffracting structure includes shrinking the replicated structure.
56. The method of claim 55 including laser etching of the replicated structure to distinguish it from similarly replicated structures.
57. The method of claim 56 including placing a transparent overcoat on the replicated structure.
58. A method of providing an authenticating pattern for objects comprising:
providing a randomly occurring condition in an anisotropic etching step during the forming of a diffracting structure in a substrate layer to produce a visibly distinguishable colored pattern that is used to validate the authenticity of an object, wherein said randomly occurring condition is produced by subjecting the substrate layer to randomly varying light during photochemical etching of the light diffracting structure.
providing a randomly occurring condition in an anisotropic etching step during the forming of a diffracting structure in a substrate layer to produce a visibly distinguishable colored pattern that is used to validate the authenticity of an object, wherein said randomly occurring condition is produced by subjecting the substrate layer to randomly varying light during photochemical etching of the light diffracting structure.
59. The method of claim 58 including:
providing another substrate layer, replicating the pattern of the diffracting structure into the another substrate layer by stamping or molding processes using the diffracting structure of the first mentioned substrate as a master plate, wherein the extent of parameter variations of said authenticating pattern caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic etching step during the manufacturing of said diffracting structure and depositing a transparent overcoat layer on said another substrate layer wherein said overcoat layer fills pits in the light diffracting structure.
providing another substrate layer, replicating the pattern of the diffracting structure into the another substrate layer by stamping or molding processes using the diffracting structure of the first mentioned substrate as a master plate, wherein the extent of parameter variations of said authenticating pattern caused by said replication step is insignificant compared to the extent of parameter variations defined by said anisotropic etching step during the manufacturing of said diffracting structure and depositing a transparent overcoat layer on said another substrate layer wherein said overcoat layer fills pits in the light diffracting structure.
60. The method of claim 59 including adding personalizing information in the form of graphically pictorial or alphanumeric information or any combination thereof to the another substrate layer or to the overcoat layer or to both of them, wherein adding said information comprises writing said information into said layers by laser burning, stamping or molding processes.
61. The method of claim 60 including forming said light diffracting structure with more than 2000 lines/mm to assure total internal reflectance within said overcoat layer.
62. The method of claim 61 including bonding said transparent overcoat layer to said another substrate layer in a manner sufficiently secure to prevent said overcoat layer from being removed from said substrate layer without destroying said substrate layer.
63. The method of claim 62 including providing a metal layer overcoating for said diffracting structure.
64. The method of claim 63 including using transparent amorphous materials as the material of said substrate layer and said overcoat layer.
65. The method of claim 64 including forming said authentication label is a substantially circular shape with the authenticating patterns concentrically arranged around the graphic personalizing information provided in the center of the circle.
66. The method of claim 65 including using a hologram as said graphic personalizing information.
67. The method of claim 66 including using a relief grating as said light diffracting structure.
68. A method of fabricating a light diffracting structure used for authentication purposes comprising:
providing data for a pattern of a light diffracting structure;
using an anisotropic etching process to fabricate the light diffracting structure from the data; and inserting a randomly occurring condition in the anisotropic etching process so that the light diffracting structure produces a unique colored pattern visibly distinguishable from other patterns in natural light by the naked eye so that the colored pattern can be used in validating the authenticity of an object attached to the structure.
providing data for a pattern of a light diffracting structure;
using an anisotropic etching process to fabricate the light diffracting structure from the data; and inserting a randomly occurring condition in the anisotropic etching process so that the light diffracting structure produces a unique colored pattern visibly distinguishable from other patterns in natural light by the naked eye so that the colored pattern can be used in validating the authenticity of an object attached to the structure.
69. The method of claim 68 including using as the pattern for a light diffracting structure a relief grating with peak-to-valley ratios b:a and line depths c as parameters of the data.
70. A method of fabricating an authenticating label for an object comprising:
providing data for a pattern of a light diffracting structure;
inserting a randomly occurring condition in an anisotropic process used to manufacture a master of a light diffracting structure to cause random variations in the pattern defined by the data which variations provide a unique color pattern visibly distinguishable by the naked human eye without special illumination or equipment includes:
providing a substrate layer, depositing a photoresist layer on said substrate layer, providing a mask pattern defined by said data into said photoresist layer, anisotropically etching pits defined by the mask pattern into said substrate layer by photochemical etching with variable illumination, and removing said photoresist layer;
replicating the diffracting structure using the master; and covering the replicated diffracting structure with an overcoat layer.
providing data for a pattern of a light diffracting structure;
inserting a randomly occurring condition in an anisotropic process used to manufacture a master of a light diffracting structure to cause random variations in the pattern defined by the data which variations provide a unique color pattern visibly distinguishable by the naked human eye without special illumination or equipment includes:
providing a substrate layer, depositing a photoresist layer on said substrate layer, providing a mask pattern defined by said data into said photoresist layer, anisotropically etching pits defined by the mask pattern into said substrate layer by photochemical etching with variable illumination, and removing said photoresist layer;
replicating the diffracting structure using the master; and covering the replicated diffracting structure with an overcoat layer.
71. The method of claim 70 wherein said master is manufactured using an anisotropic semiconductor fabrication process.
72. The method of claim 71 wherein the replication of the diffracting structure includes shrinking the replicated structure.
73. The method of claim 70 wherein the replication of the diffracting structure includes shrinking the replicated structure.
74. The method of claim 73 wherein said replicating involves a molding process.
75. The method of claim 74 including laser etching of the replicated structure to distinguish it from similarly replicated structures.
76. The method of claim 75 including placing a transparent overcoat on the replicated structure.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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EP94117660.4 | 1994-11-09 | ||
EP94117660A EP0712012A1 (en) | 1994-11-09 | 1994-11-09 | Authentication label and authenticating pattern incorporating diffracting structure and method of fabricating them |
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CA2155382A1 CA2155382A1 (en) | 1996-05-10 |
CA2155382C true CA2155382C (en) | 2002-01-29 |
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CA002155382A Expired - Fee Related CA2155382C (en) | 1994-11-09 | 1995-08-03 | Authentication label and authenticating pattern incorporating diffracting structure and method of fabricating them |
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US (3) | US5629070A (en) |
EP (1) | EP0712012A1 (en) |
JP (1) | JP3138197B2 (en) |
KR (1) | KR100260679B1 (en) |
CA (1) | CA2155382C (en) |
TW (1) | TW294636B (en) |
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DE102008005019B4 (en) | 2008-01-17 | 2010-08-05 | Ovd Kinegram Ag | Foil element and the use of this foil element |
BRPI0802867A2 (en) * | 2008-07-28 | 2010-03-30 | Carlos Andre Xavier Villela | variable position printing, document authentication method, and counterfeit monitoring method |
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JP6641738B2 (en) * | 2015-02-04 | 2020-02-05 | 凸版印刷株式会社 | Display body and display body observation method |
JP6520359B2 (en) * | 2015-04-30 | 2019-05-29 | 凸版印刷株式会社 | Display body, article, original plate, and method of producing original plate |
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US3894756A (en) * | 1971-10-18 | 1975-07-15 | Optronics Int | Identification card having a reference beam coded hologram |
US4892385A (en) * | 1981-02-19 | 1990-01-09 | General Electric Company | Sheet-material authenticated item with reflective-diffractive authenticating device |
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US4510673A (en) * | 1983-06-23 | 1985-04-16 | International Business Machines Corporation | Laser written chip identification method |
US4547002A (en) * | 1983-11-10 | 1985-10-15 | U.S. Banknote Corporation | Credit and identification cards having pieces of diffraction grating therein |
DE3610333A1 (en) * | 1985-04-19 | 1986-11-27 | Siemens AG, 1000 Berlin und 8000 München | Method for producing a surface grating (lattice, grid) having a specific grating constant on a lower-lying surface region of a mesastructure |
JPS622207A (en) * | 1985-06-28 | 1987-01-08 | Hitachi Ltd | Diffraction grating and its production |
US4832445A (en) * | 1986-05-16 | 1989-05-23 | American Bank Note Holographics, Inc. | Security diffraction devices difficult to exactly duplicate |
US5145212A (en) * | 1988-02-12 | 1992-09-08 | American Banknote Holographics, Inc. | Non-continuous holograms, methods of making them and articles incorporating them |
US5003600A (en) * | 1989-08-03 | 1991-03-26 | The United States Of America As Represented By The Department Of Energy | Diffraction gratings used as identifying markers |
JP2754785B2 (en) * | 1989-09-20 | 1998-05-20 | ソニー株式会社 | Method for manufacturing high-density optical disk |
TW236016B (en) * | 1992-02-29 | 1994-12-11 | Leonhard Kurz & Co |
-
1994
- 1994-11-09 EP EP94117660A patent/EP0712012A1/en not_active Withdrawn
-
1995
- 1995-02-13 TW TW084101262A patent/TW294636B/zh active
- 1995-05-19 US US08/445,148 patent/US5629070A/en not_active Expired - Fee Related
- 1995-08-03 CA CA002155382A patent/CA2155382C/en not_active Expired - Fee Related
- 1995-10-31 JP JP07283160A patent/JP3138197B2/en not_active Expired - Fee Related
- 1995-11-08 KR KR1019950040345A patent/KR100260679B1/en not_active IP Right Cessation
-
1997
- 1997-01-10 US US08/781,670 patent/US5856070A/en not_active Expired - Fee Related
-
1998
- 1998-08-31 US US09/144,285 patent/US6057082A/en not_active Expired - Fee Related
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KR100260679B1 (en) | 2000-07-01 |
TW294636B (en) | 1997-01-01 |
US6057082A (en) | 2000-05-02 |
EP0712012A1 (en) | 1996-05-15 |
JP3138197B2 (en) | 2001-02-26 |
US5856070A (en) | 1999-01-05 |
JPH08211215A (en) | 1996-08-20 |
KR960019012A (en) | 1996-06-17 |
US5629070A (en) | 1997-05-13 |
CA2155382A1 (en) | 1996-05-10 |
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