CA2589364C - Preserved and enhanced holographic and optically variable devices and method for making the same - Google Patents
Preserved and enhanced holographic and optically variable devices and method for making the same Download PDFInfo
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- CA2589364C CA2589364C CA2589364A CA2589364A CA2589364C CA 2589364 C CA2589364 C CA 2589364C CA 2589364 A CA2589364 A CA 2589364A CA 2589364 A CA2589364 A CA 2589364A CA 2589364 C CA2589364 C CA 2589364C
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- optically variable
- coating
- polymer
- enhancer particles
- optical enhancer
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- 238000000034 method Methods 0.000 title claims description 30
- 239000003623 enhancer Substances 0.000 claims abstract description 62
- 239000002245 particle Substances 0.000 claims abstract description 60
- 238000000576 coating method Methods 0.000 claims abstract description 59
- 230000003287 optical effect Effects 0.000 claims abstract description 58
- 239000011248 coating agent Substances 0.000 claims abstract description 56
- 239000006185 dispersion Substances 0.000 claims abstract description 37
- 239000007788 liquid Substances 0.000 claims abstract description 29
- 239000000758 substrate Substances 0.000 claims abstract description 19
- 239000002904 solvent Substances 0.000 claims abstract description 12
- 239000010410 layer Substances 0.000 claims description 41
- 229920000642 polymer Polymers 0.000 claims description 38
- 229910052751 metal Inorganic materials 0.000 claims description 18
- 239000002184 metal Substances 0.000 claims description 18
- 229920000307 polymer substrate Polymers 0.000 claims description 17
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 15
- 229910052782 aluminium Inorganic materials 0.000 claims description 12
- 238000007639 printing Methods 0.000 claims description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 239000005083 Zinc sulfide Substances 0.000 claims description 6
- 239000012790 adhesive layer Substances 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000011241 protective layer Substances 0.000 claims description 6
- 229910052984 zinc sulfide Inorganic materials 0.000 claims description 6
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 claims description 6
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052797 bismuth Inorganic materials 0.000 claims description 3
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 239000011651 chromium Substances 0.000 claims description 3
- 230000002708 enhancing effect Effects 0.000 claims description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 239000010931 gold Substances 0.000 claims description 3
- 229910052738 indium Inorganic materials 0.000 claims description 3
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 3
- 235000012239 silicon dioxide Nutrition 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 229910052709 silver Inorganic materials 0.000 claims description 3
- 239000004332 silver Substances 0.000 claims description 3
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims 4
- 239000011230 binding agent Substances 0.000 claims 2
- 239000002923 metal particle Substances 0.000 claims 2
- 239000000463 material Substances 0.000 description 12
- 239000002002 slurry Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 150000004706 metal oxides Chemical class 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- 230000000737 periodic effect Effects 0.000 description 4
- -1 polyethylene terephthalate Polymers 0.000 description 4
- 229920000139 polyethylene terephthalate Polymers 0.000 description 4
- 239000005020 polyethylene terephthalate Substances 0.000 description 4
- 239000010419 fine particle Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004049 embossing Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000001465 metallisation Methods 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000002310 reflectometry Methods 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 238000005019 vapor deposition process Methods 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 1
- 229920006397 acrylic thermoplastic Polymers 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 239000011127 biaxially oriented polypropylene Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000007647 flexography Methods 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 238000001093 holography Methods 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 239000002932 luster Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000013047 polymeric layer Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 238000011176 pooling Methods 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000003362 replicative effect Effects 0.000 description 1
- ISXSCDLOGDJUNJ-UHFFFAOYSA-N tert-butyl prop-2-enoate Chemical compound CC(C)(C)OC(=O)C=C ISXSCDLOGDJUNJ-UHFFFAOYSA-N 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- 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
-
- 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
- G03H1/0252—Laminate comprising a hologram layer
-
- 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
- B42D25/40—Manufacture
- B42D25/45—Associating two or more layers
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
-
- 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
- G03H1/0236—Form or shape of the hologram when not registered to the substrate, e.g. trimming the hologram to alphanumerical shape
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
-
- 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
- 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
- G03H1/18—Particular processing of hologram record carriers, e.g. for obtaining blazed holograms
- G03H2001/187—Trimming process, i.e. macroscopically patterning the hologram
-
- 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
- G03H2240/55—Thickness
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2250/00—Laminate comprising a hologram layer
- G03H2250/36—Conform enhancement layer
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2250/00—Laminate comprising a hologram layer
- G03H2250/43—One layer having dispersed particles
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2270/00—Substrate bearing the hologram
- G03H2270/52—Integrated surface relief hologram without forming layer
-
- 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
- Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
- Y10T156/10—Methods of surface bonding and/or assembly therefor
- Y10T156/1002—Methods of surface bonding and/or assembly therefor with permanent bending or reshaping or surface deformation of self sustaining lamina
- Y10T156/1007—Running or continuous length work
- Y10T156/1023—Surface deformation only [e.g., embossing]
Abstract
An optically variable device (10, 30, 50) has a substrate (12, 32) with an optically variable relief (16, 36) and a coating (18, 38) on the optically variable relief . The coating is applied as a liquid dispersion including a plurality of optical enhancer particles (20, 38) in a solvent.
Description
Description PRESERVED AND ENHANCED HOLOGRAPHIC AND
OPTICALLY VARIABLE DEVICES AND METHOD FOR
MAKING THE SAME
FIELD OF THE INVENTION
Ill The present invention relates to holography, and, more particularly, to holograms and/or diffraction gratings which are embossed or cast into a film.
BACKGROUND OF THE INVENTION
[21 Holograms and diffraction gratings can be attached to a document or other articles containing printing and/or other information, such as a magnetic strip. For example, holograms are attached to credit cards in order to authenticate genuineness and increase the difficulty of counterfeiting credit cards. Holograms can be used as anti-counterfeiting devices on other types of documents, such as stock certificates, iden-tification badges, passports, checks and even currency. Holograms and diffraction gratings are also attached to, or formed within, documents and articles for other reasons, such as for decorative effect. Packaging materials can have holograms and/or diffraction gratings for decorative or authenticating effects.
[31 Holograms can be created by replicating the interference pattern of the hologram in a film via a surface contour in the film. When light is incident on this surface pattern, an observer views an image according to the information stored in the hologram. A
diffraction grating can be made in a similar manner. When used for the purposes described above, the hologram or diffraction grating will typically be adjacent other materials, such as an adhesive, which can optically obscure the pattern of the device.
There is a need therefore to preserve and enhance the patterns of the holograms and/or diffraction gratings.
[41 More specifically, holographic and diffraction patterns for security and product en-hancement purposes can be produced in a process which employs a carrier film onto which an embossable layer is deposited. The layers are embossed via a conventional holographic embossing process, after which the pattern is preserved and enhanced via vapor deposition of a metal, or vapor deposition of a material such as zinc sulfide which has an adequate difference of index of refraction versus the index of refraction of the embossable layer. In the vapor deposition process, the evaporated material forms a layer on the pattern, preserving the pattern. The pattern is further processed by either depositing a heat-activated adhesive or a pressure sensitive adhesive.
[51 An example of the vapor deposition process for preserving a holographic pattern is a vacuum metallization process. In this process, a roll of material is placed in a vacuum chamber that contains a heating system and a roll of aluminum wire. The heating system includes an inter-metallic boat, furnace or crucible, that acts like a resistor and is subjected to very high heat. The aluminum wire is fed into the boat, and as it contacts the boat, the metal is vaporized. Concurrently, the roll of material containing holographic patterns is unwound, passed over a series of guide rolls and a chilled roll, and then rewound. The evaporated aluminum forms a layer on the film of material to preserve and enhance the image created by the holographic pattern. Although this known system has proven to be useful, the equipment required to perform the process is generally expensive to make and operate.
Further, this method does not desirably lend itself to selective application of the metal, as is desired when the holographic pattern only covers a fraction of the area of the material. Instead, the entire surface exposed in the chamber is covered by the vapor. Coating the non-holographic areas adds undesirable waste and cost to the process and end product.
[6] What are needed in the art are preserved and enhanced holographic and diffraction patterns and a method for making them which are relatively inexpensive to make and operate, and which are capable of selectively applying the material to preserve and enhance the patterns.
SUMMARY OF THE INVENTION
[7] The present invention provides preserved and enhanced holographic and diffraction patterns having a coating of optical enhancer particles applied as a liquid dispersion of optical enhancer particles in a solvent.
[8] The invention in one broad aspect pertains to an optically variable structure, comprising an optically variable relief embossed on a polymer substrate or an embossable polymer layer and a liquid dispersion coating on the optically variable relief. The liquid dispersion coating comprises an amount of a residual polymer bonded to a plurality of optical enhancer particles during their production and the plurality of optical enhancer particles having an index of refraction differing by a minimum of 0.2 from that of the polymer substrate or the embossable polymer layer, the amount of the residual polymer providing adhesion of the plurality of 2a optical enhancers to the polymer substrate.
[9] Another aspect of the invention pertains to an optically variable device, comprising an optically variable relief embossed on a polymer substrate or an embossable polymer layer and a plurality of optical enhancer particles in a film of coating applied on the optically variable relief and bonded to the optically variable relief by a residual polymer bonded to the plurality of optical enhancer particles during their production. The film of coating has a thickness in a range between and 30 nanometers or multiples of that range, a size of each of the plurality of optical enhancer particles in the film of coating being between 10 and 13 microns.
[10] Still further, the invention provides a method of enhancing an optically variable structure, comprising the steps of providing an optically variable relief embossed on a polymer substrate or an embossable polymer layer and forming a film with a thickness in a range between 10 and 30 nanometers or multiples of that range over the optically variable layer by applying a liquid coating to the optically variable relief. The liquid coating comprises an amount of a residual polymer bonded to a plurality of optical enhancers during their production and the plurality of optical enhancer particles are of a size between 10 and 13 microns having an index of refraction differing by a minimum off 0.2 from that of the polymer substrate or the embossable polymer layer. The amount of the residual polymer provides adhesion of the plurality of optical enhancers to the polymer substrate.
[11] An advantage of the present invention is that it preserves an optically variable relief.
[12] Another advantage of the present invention is that it enhances an optically variable relief.
[13] A further advantage of the present invention is that it is economical to produce.
OPTICALLY VARIABLE DEVICES AND METHOD FOR
MAKING THE SAME
FIELD OF THE INVENTION
Ill The present invention relates to holography, and, more particularly, to holograms and/or diffraction gratings which are embossed or cast into a film.
BACKGROUND OF THE INVENTION
[21 Holograms and diffraction gratings can be attached to a document or other articles containing printing and/or other information, such as a magnetic strip. For example, holograms are attached to credit cards in order to authenticate genuineness and increase the difficulty of counterfeiting credit cards. Holograms can be used as anti-counterfeiting devices on other types of documents, such as stock certificates, iden-tification badges, passports, checks and even currency. Holograms and diffraction gratings are also attached to, or formed within, documents and articles for other reasons, such as for decorative effect. Packaging materials can have holograms and/or diffraction gratings for decorative or authenticating effects.
[31 Holograms can be created by replicating the interference pattern of the hologram in a film via a surface contour in the film. When light is incident on this surface pattern, an observer views an image according to the information stored in the hologram. A
diffraction grating can be made in a similar manner. When used for the purposes described above, the hologram or diffraction grating will typically be adjacent other materials, such as an adhesive, which can optically obscure the pattern of the device.
There is a need therefore to preserve and enhance the patterns of the holograms and/or diffraction gratings.
[41 More specifically, holographic and diffraction patterns for security and product en-hancement purposes can be produced in a process which employs a carrier film onto which an embossable layer is deposited. The layers are embossed via a conventional holographic embossing process, after which the pattern is preserved and enhanced via vapor deposition of a metal, or vapor deposition of a material such as zinc sulfide which has an adequate difference of index of refraction versus the index of refraction of the embossable layer. In the vapor deposition process, the evaporated material forms a layer on the pattern, preserving the pattern. The pattern is further processed by either depositing a heat-activated adhesive or a pressure sensitive adhesive.
[51 An example of the vapor deposition process for preserving a holographic pattern is a vacuum metallization process. In this process, a roll of material is placed in a vacuum chamber that contains a heating system and a roll of aluminum wire. The heating system includes an inter-metallic boat, furnace or crucible, that acts like a resistor and is subjected to very high heat. The aluminum wire is fed into the boat, and as it contacts the boat, the metal is vaporized. Concurrently, the roll of material containing holographic patterns is unwound, passed over a series of guide rolls and a chilled roll, and then rewound. The evaporated aluminum forms a layer on the film of material to preserve and enhance the image created by the holographic pattern. Although this known system has proven to be useful, the equipment required to perform the process is generally expensive to make and operate.
Further, this method does not desirably lend itself to selective application of the metal, as is desired when the holographic pattern only covers a fraction of the area of the material. Instead, the entire surface exposed in the chamber is covered by the vapor. Coating the non-holographic areas adds undesirable waste and cost to the process and end product.
[6] What are needed in the art are preserved and enhanced holographic and diffraction patterns and a method for making them which are relatively inexpensive to make and operate, and which are capable of selectively applying the material to preserve and enhance the patterns.
SUMMARY OF THE INVENTION
[7] The present invention provides preserved and enhanced holographic and diffraction patterns having a coating of optical enhancer particles applied as a liquid dispersion of optical enhancer particles in a solvent.
[8] The invention in one broad aspect pertains to an optically variable structure, comprising an optically variable relief embossed on a polymer substrate or an embossable polymer layer and a liquid dispersion coating on the optically variable relief. The liquid dispersion coating comprises an amount of a residual polymer bonded to a plurality of optical enhancer particles during their production and the plurality of optical enhancer particles having an index of refraction differing by a minimum of 0.2 from that of the polymer substrate or the embossable polymer layer, the amount of the residual polymer providing adhesion of the plurality of 2a optical enhancers to the polymer substrate.
[9] Another aspect of the invention pertains to an optically variable device, comprising an optically variable relief embossed on a polymer substrate or an embossable polymer layer and a plurality of optical enhancer particles in a film of coating applied on the optically variable relief and bonded to the optically variable relief by a residual polymer bonded to the plurality of optical enhancer particles during their production. The film of coating has a thickness in a range between and 30 nanometers or multiples of that range, a size of each of the plurality of optical enhancer particles in the film of coating being between 10 and 13 microns.
[10] Still further, the invention provides a method of enhancing an optically variable structure, comprising the steps of providing an optically variable relief embossed on a polymer substrate or an embossable polymer layer and forming a film with a thickness in a range between 10 and 30 nanometers or multiples of that range over the optically variable layer by applying a liquid coating to the optically variable relief. The liquid coating comprises an amount of a residual polymer bonded to a plurality of optical enhancers during their production and the plurality of optical enhancer particles are of a size between 10 and 13 microns having an index of refraction differing by a minimum off 0.2 from that of the polymer substrate or the embossable polymer layer. The amount of the residual polymer provides adhesion of the plurality of optical enhancers to the polymer substrate.
[11] An advantage of the present invention is that it preserves an optically variable relief.
[12] Another advantage of the present invention is that it enhances an optically variable relief.
[13] A further advantage of the present invention is that it is economical to produce.
[141 A yet further advantage of the present invention is that it can be selectively applied to portions of a substrate, in particular, portions of the substrate which include an optically variable relief.
[151 A yet further advantage of the present invention is that it is economical from a capital investment perspective.
[161 Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.
BRIEF DESCRIPTION OF THE DRAWINGS
[171 Fig. 1 is a cross-sectional view of an optically variable device of the present invention with a substrate which includes an embossable layer with an optically variable relief;
[181 Fig. 2 is a cross-sectional view of an optically variable device of the present invention with a substrate which includes an optically variable relief; and [191 Fig. 3 is a plan view of an optically variable device of the present invention where the liquid dispersion is selectively applied to a predetermined portion of the substrate of the optically variable device.
[201 Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of con-struction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use herein of 'including', 'comprising' and variations thereof is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items and equivalents thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[211 Referring now to the drawings, and more particularly to Fig. 1, there is shown an optically variable device 10 which generally has a substrate 12 having an embossable layer 14 thereon. Embossable layer 14 includes an optically variable relief 16 formed therein. A coating 18 on optically variable relief 16 includes a plurality of optical enhancer particles 20 applied as a dispersion in a solvent. Optically variable device 10 can include a layer 22, such as an adhesive layer and/or a protective layer, applied on the plurality of optical enhancer particles 20.
[221 Embossable layer 14 can be embossed with optically variable relief 16 by a holographic embossing process, for example.
[231 Optically variable relief 16 can be at least one of a holographic pattern and a diffraction grating.
[241 Coating 18 can include optical enhancer particles 20 in the form of aluminum platelets or flakes with a relatively controlled particle size, provided as a dispersion in a solvent. The aluminum flake dispersion can be produced from vapor deposited aluminum metal which is deposited onto polymer release coated film, such as polyethylene terephthalate (PET), and then stripped off the film carrier and processed to a fine particle size of approximately 10 - 13 micron or less. Multiple vapor deposited layers can be separated by polymeric release coatings, to yield thin platelets when stripped from the film The polymeric release coat is soluble in an organic solvent, which facilitates stripping the metal/polymer layers from the film carrier and allows for pumping a slurry of the stripped fragments from the stripping tank to equipment that further processes the metal flake suspension into a more concentrated, finely dispersed slurry, of controlled particle size (of 10 - 13 micron), and normally about 10 - 20%
metal flake content [251 The use of fine particle size aluminum flakes or platelets having a brilliant luster in-tensifies and preserves a holographic image to a similar degree as if a metal, metal oxide or high index of refraction coating were vapor deposited directly onto the embossed image, such as optically variable relief 16.
[261 Vapor deposited metals, metal oxides or high index of refraction material, such as zinc sulfide, have been used to preserve and enhance a holographic image. An accepted rule for using a high or low index of refraction coating, is that there should be a minimum of 0.5 - 1.0 difference between the index of refraction of the embossable polymer or polymer film, and the index of refraction of the image enhancer.
Known polymers used as substrate 12 and/or embossable layer 14, such as acrylics, have an index of refraction in the range of 1.45 - 1.65. Preferably the index of refraction of the image enhancer should be substantially higher or lower. A material having an index of refraction of 2.1 - 2.2, as in the case of zinc sulfide, makes an excellent transparent image preserver and enhancer. The image can also be preserved by using other high index of refraction liquid coatings where a minimum difference of index of refraction of 0.2 or more is recommended.
[271 In one embodiment, the present invention provides a slurry or dispersion produced from vapor deposited aluminum metal enhancer particles 20 in the form of flakes or platelets that are between about 10 and 30 nanometers thick and have a controlled particle size. Particles 20 preserve and enhance optically variable relief 16 when applied onto optically variable relief 16. The aluminum flake dispersion can be viewed much like a dispersion of microscopically thin micromirrors that form a brilliant surface when applied into optically variable relief 16, and provide a reflectivity similar to the reflectivity of vapor deposited metal. Metal dispersions are available from Wol-stenholme International Ltd. and from Eckart GmbH & Co. KG., with metal flakes suspended in various organic solvents compatible with various polymers that may be used as substrate 12 and/or embossable layer 14. Water-borne dispersions also are available.
[281 In order to produce a solvent based liquid dispersion to preserve and/or enhance optically variable relief 16, sufficient solvent is added to dilute the slurry to a viscosity that allows applying the flake suspension/dispersion via commercial coating or printing methods. To produce a water solvent based liquid dispersion, either water is added, or a mixture of alcohol and water is added to dilute the slurry to a viscosity that will allow coating the flake suspension/dispersion via commercial coating or printing methods.
[291 The present invention allows for the use of commercial printing and coating methods such as gravure, flexography, rotogravure, offset, intaglio and lithography to deposit a thin reflective coating 18 of the aluminum metal flake particles 20 onto optically variable relief 16. The dispersion can be applied as an overall coating across the web, or spot printed directly onto an image, leaving the surrounding area uncoated.
The aluminum flake dispersion or coating is dried via conventional drying methods on the coating/printing equipment. The present invention is not limited to the above commercial printing methods; other commercial printing, coating and spray application methods can be employed.
[301 In the present invention, optical enhancer particles 20 can contain a small amount of release coat polymer, which is not removed during the rinsing process of the flake, and which can remain bonded to the flake. The small percentage of residual polymer is sufficient to form a film that has sufficient adhesion to optically variable relief 16. If necessary, a small amount of polymer can be added. However, since most polymers with average index of refraction of 1.45 - 1.65 (neither high or low) can render the slurry unsuitable to preserve the image (because it either matches the index of refraction of the embossable surface 14 or does not vary substantially from the polymer), the amount of additional polymer added to the slurry must remain small, typically in the 0.1 % - 1.0% range based on total volume.
[311 A protective or adhesive layer 22 can be deposited over optically variable relief 16 (preserved by coating 18, and more particularly, optical enhancer particles 20), if needed. Care is taken to select protective or adhesive layer 22 such that coating 18 or optical enhancer particles 20 are not attacked or otherwise degraded.
[321 If optically variable relief 16 is embossed into a polymeric layer, care is taken not to attack or dissolve the embossable layer, with coating 18, and particularly the solvent used in making the dispersion. Preferably, a water based metal flake dispersion is employed for coating 18, which does not attack or dissolve the polymeric embossable layer 14, and does not erase optically variable relief 16. If needed, a small amount of additional polymer can be added to the water based dispersion, but the amount added depends on the organic residuals in the slurry and is kept small enough in order not to interfere with the image preservation.
[331 Optical enhancer particles 20 can have a complex index of refraction such as common in reflective metals; or can be a purely refractive material. Optical enhancer particles 20 can include metals such as aluminum, as described above.
Chromium, indium, bismuth, silver, gold, etc. are also suitable, but the invention is not limited to those metals. Metal oxides, such as aluminum oxide, and non-metal oxides, such as silicone monoxide and silicon dioxide, also are suitable. A high index of refraction inorganic such as zinc sulfide is also suitable. A slurry is prepared from the above products, and processed into a fine particle size similar to the aluminum flake dispersion described above.
[341 In general, optical enhancer particles can be comprised of a metal and/or a plurality of metal flakes. Substrate 12 can include a first index of refraction (which may be the index of refraction of embossable layer 14), and the plurality of optical enhancer particles 20 can include a second index of refraction. A difference between the first index of refraction and the second index of refraction can be preferably greater than 0.2.
[351 Coating 18 can provide a consistent thickness 24 of optical enhancer particles 20 on optically variable relief 16. Consistent thickness 24 can be, for the example of aluminum flakes, in a range of approximately between 10 and 30 nanometers, or multiples of such a range. Each of optical enhancer particles 20 can be approximately between 10 and 13 microns in a direction approximately transverse to consistent thickness 24. The flake structure of optical enhancer particles 20 allows optical enhancer particles 20 to orient themselves in consistent thickness 24, i.e., particles do not stand on edge. The flake structure and size of particles 20 are sufficiently small to fit into optically variable reliefs 16, without pooling.
[361 Pre-forming substrate 12 with embossable layer 14 is desirable, but optically variable reliefs 16, such as holographic patterns and diffraction gratings, can be directly embossed into polyethylene terephthalate (PET) films, without an embossable layer 14. Additionally, co-extruded biaxially oriented polypropylene (BOPP) can be embossed with optically variable reliefs, for use in laminations. Variations and modi-fications of the foregoing are within the scope of the present invention.
[371 In the embodiment of Fig. 2, optically variable device 30 includes substrate 32 onto which is directly applied optically variable relief 34. A coating 36 (similar to coating 18 as described previously) on optically variable relief 34 includes a plurality of optical enhancer particles 38 (similar to optical enhancer particles 20 as described previously) in a solvent. Optically variable device 30 can include layer 40 which can be a protective and/or adhesive layer, for example. Coating 36 can provide a thickness 42, which can be a consistent thickness, of optical enhancer particles 38 on optically variable relief 34.
[381 Although optically variable relief 16 is depicted as more of a periodic structure, and optically variable relief 34 is depicted as more of a non-periodic structure, either of optically variable relief 16 or optically variable relief 34 can have a structure which is periodic or non-periodic or a combination thereof. Further, although optical enhancer particles 20 are shown in a relatively continuous layer and optical enhancer particles 38 are shown disjointed or discontinuous, either optical enhancer particles 20 or optical enhancer particles 38 can form a layer or layers which are continuous, discontinuous, overlapping or some combination thereof.
[391 Other layers can be added to either optically variable device 10 or optically variable device 30 as are required.
[401 The liquid dispersion of the present invention can be applied by readily available printing methods, and other application methods, as previously described, which allows for selective application of the liquid dispersion thereby achieving cost savings in materials and capital equipment. Fig. 3 illustrates a plan view of an optically variable device 50 of the present invention where the liquid dispersion is selectively applied to predetermined portion(s) 52 of a substrate 54 of the optically variable device. Each of predetermined portions 52 can have the cross-sectional characteristics of either Figs. 1 and/or 2, and other corresponding characteristics, as previously described. For example, substrate 54 can include an embossable layer with an optically variable relief and/or can have the optically variable relief on substrate 54 with no embossable layer. Additionally, the optically variable relief can cover an entire surface of substrate 54, can cover only predetermined portions 52, or some combination thereof.
[411 In use, the present invention includes a method of enhancing an optically variable device, with steps of. providing both a substrate 12, 32, 54 having an optically variable relief 16, 34 and a dispersion having a plurality of optical enhancer particles 20, 38 in a solvent; applying the dispersion as a coating 18, 36 on optically variable relief 16, 34;
and maintaining a consistent thickness 24, 42 of optical enhancer particles 20, 38 on optically variable relief 16, 34. The applying step can selectively apply coating 18, 36 to a predetermined portion 52 of the substrate. The dispersion for coating 18, 36 can be selected to limit a size of each of optical enhancer particles 20, 38 to approximately between 10 and 13 microns. The applying step can use a printing technique or other coating, spray or application techniques.
[421 It is understood that the invention disclosed and defined herein extends to all al-ternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative em-bodiments to the extent permitted by the prior art.
[431 Various features of the invention are set forth in the following claims.
[151 A yet further advantage of the present invention is that it is economical from a capital investment perspective.
[161 Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.
BRIEF DESCRIPTION OF THE DRAWINGS
[171 Fig. 1 is a cross-sectional view of an optically variable device of the present invention with a substrate which includes an embossable layer with an optically variable relief;
[181 Fig. 2 is a cross-sectional view of an optically variable device of the present invention with a substrate which includes an optically variable relief; and [191 Fig. 3 is a plan view of an optically variable device of the present invention where the liquid dispersion is selectively applied to a predetermined portion of the substrate of the optically variable device.
[201 Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of con-struction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use herein of 'including', 'comprising' and variations thereof is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items and equivalents thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[211 Referring now to the drawings, and more particularly to Fig. 1, there is shown an optically variable device 10 which generally has a substrate 12 having an embossable layer 14 thereon. Embossable layer 14 includes an optically variable relief 16 formed therein. A coating 18 on optically variable relief 16 includes a plurality of optical enhancer particles 20 applied as a dispersion in a solvent. Optically variable device 10 can include a layer 22, such as an adhesive layer and/or a protective layer, applied on the plurality of optical enhancer particles 20.
[221 Embossable layer 14 can be embossed with optically variable relief 16 by a holographic embossing process, for example.
[231 Optically variable relief 16 can be at least one of a holographic pattern and a diffraction grating.
[241 Coating 18 can include optical enhancer particles 20 in the form of aluminum platelets or flakes with a relatively controlled particle size, provided as a dispersion in a solvent. The aluminum flake dispersion can be produced from vapor deposited aluminum metal which is deposited onto polymer release coated film, such as polyethylene terephthalate (PET), and then stripped off the film carrier and processed to a fine particle size of approximately 10 - 13 micron or less. Multiple vapor deposited layers can be separated by polymeric release coatings, to yield thin platelets when stripped from the film The polymeric release coat is soluble in an organic solvent, which facilitates stripping the metal/polymer layers from the film carrier and allows for pumping a slurry of the stripped fragments from the stripping tank to equipment that further processes the metal flake suspension into a more concentrated, finely dispersed slurry, of controlled particle size (of 10 - 13 micron), and normally about 10 - 20%
metal flake content [251 The use of fine particle size aluminum flakes or platelets having a brilliant luster in-tensifies and preserves a holographic image to a similar degree as if a metal, metal oxide or high index of refraction coating were vapor deposited directly onto the embossed image, such as optically variable relief 16.
[261 Vapor deposited metals, metal oxides or high index of refraction material, such as zinc sulfide, have been used to preserve and enhance a holographic image. An accepted rule for using a high or low index of refraction coating, is that there should be a minimum of 0.5 - 1.0 difference between the index of refraction of the embossable polymer or polymer film, and the index of refraction of the image enhancer.
Known polymers used as substrate 12 and/or embossable layer 14, such as acrylics, have an index of refraction in the range of 1.45 - 1.65. Preferably the index of refraction of the image enhancer should be substantially higher or lower. A material having an index of refraction of 2.1 - 2.2, as in the case of zinc sulfide, makes an excellent transparent image preserver and enhancer. The image can also be preserved by using other high index of refraction liquid coatings where a minimum difference of index of refraction of 0.2 or more is recommended.
[271 In one embodiment, the present invention provides a slurry or dispersion produced from vapor deposited aluminum metal enhancer particles 20 in the form of flakes or platelets that are between about 10 and 30 nanometers thick and have a controlled particle size. Particles 20 preserve and enhance optically variable relief 16 when applied onto optically variable relief 16. The aluminum flake dispersion can be viewed much like a dispersion of microscopically thin micromirrors that form a brilliant surface when applied into optically variable relief 16, and provide a reflectivity similar to the reflectivity of vapor deposited metal. Metal dispersions are available from Wol-stenholme International Ltd. and from Eckart GmbH & Co. KG., with metal flakes suspended in various organic solvents compatible with various polymers that may be used as substrate 12 and/or embossable layer 14. Water-borne dispersions also are available.
[281 In order to produce a solvent based liquid dispersion to preserve and/or enhance optically variable relief 16, sufficient solvent is added to dilute the slurry to a viscosity that allows applying the flake suspension/dispersion via commercial coating or printing methods. To produce a water solvent based liquid dispersion, either water is added, or a mixture of alcohol and water is added to dilute the slurry to a viscosity that will allow coating the flake suspension/dispersion via commercial coating or printing methods.
[291 The present invention allows for the use of commercial printing and coating methods such as gravure, flexography, rotogravure, offset, intaglio and lithography to deposit a thin reflective coating 18 of the aluminum metal flake particles 20 onto optically variable relief 16. The dispersion can be applied as an overall coating across the web, or spot printed directly onto an image, leaving the surrounding area uncoated.
The aluminum flake dispersion or coating is dried via conventional drying methods on the coating/printing equipment. The present invention is not limited to the above commercial printing methods; other commercial printing, coating and spray application methods can be employed.
[301 In the present invention, optical enhancer particles 20 can contain a small amount of release coat polymer, which is not removed during the rinsing process of the flake, and which can remain bonded to the flake. The small percentage of residual polymer is sufficient to form a film that has sufficient adhesion to optically variable relief 16. If necessary, a small amount of polymer can be added. However, since most polymers with average index of refraction of 1.45 - 1.65 (neither high or low) can render the slurry unsuitable to preserve the image (because it either matches the index of refraction of the embossable surface 14 or does not vary substantially from the polymer), the amount of additional polymer added to the slurry must remain small, typically in the 0.1 % - 1.0% range based on total volume.
[311 A protective or adhesive layer 22 can be deposited over optically variable relief 16 (preserved by coating 18, and more particularly, optical enhancer particles 20), if needed. Care is taken to select protective or adhesive layer 22 such that coating 18 or optical enhancer particles 20 are not attacked or otherwise degraded.
[321 If optically variable relief 16 is embossed into a polymeric layer, care is taken not to attack or dissolve the embossable layer, with coating 18, and particularly the solvent used in making the dispersion. Preferably, a water based metal flake dispersion is employed for coating 18, which does not attack or dissolve the polymeric embossable layer 14, and does not erase optically variable relief 16. If needed, a small amount of additional polymer can be added to the water based dispersion, but the amount added depends on the organic residuals in the slurry and is kept small enough in order not to interfere with the image preservation.
[331 Optical enhancer particles 20 can have a complex index of refraction such as common in reflective metals; or can be a purely refractive material. Optical enhancer particles 20 can include metals such as aluminum, as described above.
Chromium, indium, bismuth, silver, gold, etc. are also suitable, but the invention is not limited to those metals. Metal oxides, such as aluminum oxide, and non-metal oxides, such as silicone monoxide and silicon dioxide, also are suitable. A high index of refraction inorganic such as zinc sulfide is also suitable. A slurry is prepared from the above products, and processed into a fine particle size similar to the aluminum flake dispersion described above.
[341 In general, optical enhancer particles can be comprised of a metal and/or a plurality of metal flakes. Substrate 12 can include a first index of refraction (which may be the index of refraction of embossable layer 14), and the plurality of optical enhancer particles 20 can include a second index of refraction. A difference between the first index of refraction and the second index of refraction can be preferably greater than 0.2.
[351 Coating 18 can provide a consistent thickness 24 of optical enhancer particles 20 on optically variable relief 16. Consistent thickness 24 can be, for the example of aluminum flakes, in a range of approximately between 10 and 30 nanometers, or multiples of such a range. Each of optical enhancer particles 20 can be approximately between 10 and 13 microns in a direction approximately transverse to consistent thickness 24. The flake structure of optical enhancer particles 20 allows optical enhancer particles 20 to orient themselves in consistent thickness 24, i.e., particles do not stand on edge. The flake structure and size of particles 20 are sufficiently small to fit into optically variable reliefs 16, without pooling.
[361 Pre-forming substrate 12 with embossable layer 14 is desirable, but optically variable reliefs 16, such as holographic patterns and diffraction gratings, can be directly embossed into polyethylene terephthalate (PET) films, without an embossable layer 14. Additionally, co-extruded biaxially oriented polypropylene (BOPP) can be embossed with optically variable reliefs, for use in laminations. Variations and modi-fications of the foregoing are within the scope of the present invention.
[371 In the embodiment of Fig. 2, optically variable device 30 includes substrate 32 onto which is directly applied optically variable relief 34. A coating 36 (similar to coating 18 as described previously) on optically variable relief 34 includes a plurality of optical enhancer particles 38 (similar to optical enhancer particles 20 as described previously) in a solvent. Optically variable device 30 can include layer 40 which can be a protective and/or adhesive layer, for example. Coating 36 can provide a thickness 42, which can be a consistent thickness, of optical enhancer particles 38 on optically variable relief 34.
[381 Although optically variable relief 16 is depicted as more of a periodic structure, and optically variable relief 34 is depicted as more of a non-periodic structure, either of optically variable relief 16 or optically variable relief 34 can have a structure which is periodic or non-periodic or a combination thereof. Further, although optical enhancer particles 20 are shown in a relatively continuous layer and optical enhancer particles 38 are shown disjointed or discontinuous, either optical enhancer particles 20 or optical enhancer particles 38 can form a layer or layers which are continuous, discontinuous, overlapping or some combination thereof.
[391 Other layers can be added to either optically variable device 10 or optically variable device 30 as are required.
[401 The liquid dispersion of the present invention can be applied by readily available printing methods, and other application methods, as previously described, which allows for selective application of the liquid dispersion thereby achieving cost savings in materials and capital equipment. Fig. 3 illustrates a plan view of an optically variable device 50 of the present invention where the liquid dispersion is selectively applied to predetermined portion(s) 52 of a substrate 54 of the optically variable device. Each of predetermined portions 52 can have the cross-sectional characteristics of either Figs. 1 and/or 2, and other corresponding characteristics, as previously described. For example, substrate 54 can include an embossable layer with an optically variable relief and/or can have the optically variable relief on substrate 54 with no embossable layer. Additionally, the optically variable relief can cover an entire surface of substrate 54, can cover only predetermined portions 52, or some combination thereof.
[411 In use, the present invention includes a method of enhancing an optically variable device, with steps of. providing both a substrate 12, 32, 54 having an optically variable relief 16, 34 and a dispersion having a plurality of optical enhancer particles 20, 38 in a solvent; applying the dispersion as a coating 18, 36 on optically variable relief 16, 34;
and maintaining a consistent thickness 24, 42 of optical enhancer particles 20, 38 on optically variable relief 16, 34. The applying step can selectively apply coating 18, 36 to a predetermined portion 52 of the substrate. The dispersion for coating 18, 36 can be selected to limit a size of each of optical enhancer particles 20, 38 to approximately between 10 and 13 microns. The applying step can use a printing technique or other coating, spray or application techniques.
[421 It is understood that the invention disclosed and defined herein extends to all al-ternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative em-bodiments to the extent permitted by the prior art.
[431 Various features of the invention are set forth in the following claims.
Claims (27)
1. An optically variable structure, comprising:
an optically variable relief embossed on a polymer substrate or an embossable polymer layer; and a liquid dispersion coating on said optically variable relief, said liquid dispersion coating comprising an amount of a residual polymer bonded to a plurality of optical enhancer particles during their production and the plurality of optical enhancer particles having an index of refraction differing by a minimum of ~0.2 from that of the polymer substrate or the embossable polymer layer, the amount of the residual polymer providing adhesion of the plurality of optical enhancers to the polymer substrate.
an optically variable relief embossed on a polymer substrate or an embossable polymer layer; and a liquid dispersion coating on said optically variable relief, said liquid dispersion coating comprising an amount of a residual polymer bonded to a plurality of optical enhancer particles during their production and the plurality of optical enhancer particles having an index of refraction differing by a minimum of ~0.2 from that of the polymer substrate or the embossable polymer layer, the amount of the residual polymer providing adhesion of the plurality of optical enhancers to the polymer substrate.
2. The optically variable structure of claim 1, wherein said polymer substrate or the embossable polymer layer includes at least one predetermined portion, and said liquid dispersion coating is selectively applied to said at least one predetermined portion.
3. The optically variable structure of claim 1, wherein a size of each of said plurality of optical enhancer particles is in a range between 10 and 13 microns.
4. The optically variable structure of claim 1, wherein said liquid dispersion coating provides a consistent thickness of said plurality of optical enhancer particles on said optically variable relief.
5. The optically variable structure of claim 1, wherein said optically variable relief is at least one of a holographic pattern and a diffraction grating.
6. The structure of claim 1, wherein the liquid dispersion further comprises an additional polymer in a binder to flake ratio being less than 0.01.
7. The optically variable structure of claim 1, wherein said plurality of optical enhancer particles includes at least one of aluminum, chromium, indium, bismuth, silver, gold, aluminum oxide, silicon monoxide, silicon dioxide, and zinc sulfide.
8. The optically variable structure of claim 1, wherein said liquid dispersion coating is of a suitable viscosity to be applied on said optically variable relief by a printing technique.
9. The optically variable structure of claim 1, wherein said plurality of optical enhancer particles is a plurality of metal flakes.
10. The optically variable structure of claim 9, wherein said liquid dispersion coating comprises a solvent.
11. The optically variable structure of claim 1, further comprising a protective layer applied on said plurality of optical enhancer particles.
12. The optically variable structure of claim 1, further comprising an adhesive layer applied on said plurality of optical enhancer particles.
13. The optically variable structure of claim 1, wherein said liquid dispersion coating comprises a solvent.
14. An optically variable device, comprising: an optically variable relief embossed on a polymer substrate or an embossable polymer layer; and a plurality of optical enhancer particles in a film of coating applied on said optically variable relief and bonded to the optically variable relief by a residual polymer bonded to the plurality of optical enhancer particles during their production, the film of coating having a thickness in a range between 10 and 30 nanometers or multiples of that range, a size of each of said plurality of optical enhancer particles in the film of coating being between 10 and 13 microns.
15. The optically variable device of claim 14, wherein said polymer substrate or the embossable polymer layer includes at least one predetermined portion, and said film of coating is selectively applied to said at least one predetermined portion.
16. The optically variable device of claim 14, wherein said plurality of optical enhancer particles is a plurality of metal particles.
17. The optically variable device of claim 14, wherein the amount of the residual polymer is sufficient to bond the plurality of optical enhancer particles to the optically variable relief.
18. The optically variable device of claim 14, wherein said optically variable relief is at least one of a holographic pattern and a diffraction grating.
19. The optically variable device of claim 14, wherein said plurality of optical enhancer particles comprises at least one of aluminum, chromium, indium, bismuth, silver, gold, aluminum oxide, silicon monoxide, silicon dioxide, and zinc sulfide.
20. The optically variable device of claim 14, wherein a difference between a first index of refraction of the polymer substrate or the embossable polymer layer and a second index of refraction of the plurality of optical enhancer particles is greater than ~0.2.
21. The optically variable device of claim 14, further including a protective layer applied on said film of coating with the plurality of optical enhancer particles.
22. The optically variable device of claim 14, further including an adhesive layer applied on said film of coating with the plurality of optical enhancer particles.
23. A method of enhancing an optically variable structure, comprising the steps of:
providing an optically variable relief embossed on a polymer substrate or an embossable polymer layer; and forming a film with a thickness in a range between 10 and 30 nanometers or multiples of that range over the optically variable layer by applying a liquid coating to the optically variable relief, the liquid coating comprising an amount of a residual polymer bonded to a plurality of optical enhancers during their production and the plurality of optical enhancer particles of a size between 10 and 13 microns having an index of refraction differing by a minimum off 0.2 from that of the polymer substrate or the embossable polymer layer, the amount of the residual polymer providing adhesion of the plurality of optical enhancers to the polymer substrate.
providing an optically variable relief embossed on a polymer substrate or an embossable polymer layer; and forming a film with a thickness in a range between 10 and 30 nanometers or multiples of that range over the optically variable layer by applying a liquid coating to the optically variable relief, the liquid coating comprising an amount of a residual polymer bonded to a plurality of optical enhancers during their production and the plurality of optical enhancer particles of a size between 10 and 13 microns having an index of refraction differing by a minimum off 0.2 from that of the polymer substrate or the embossable polymer layer, the amount of the residual polymer providing adhesion of the plurality of optical enhancers to the polymer substrate.
24. The method of claim 23, wherein said applying the liquid coating step selectively applies said liquid coating to a predetermined portion of said substrate.
25. The method of claim 23, wherein the liquid coating further comprises an additional polymer in a binder to flake ratio being less than 0.01.
26. The method of claim 23, wherein said applying the liquid coating step uses a printing technique.
27. The method of claim 23, wherein said applying the liquid coating step includes selecting said liquid coating so that said plurality of optical enhancer particles is a plurality of metal particles.
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| US11/004,360 | 2004-12-03 | ||
| PCT/IB2005/053819 WO2006059254A1 (en) | 2004-12-03 | 2005-11-18 | Preserved and enhanced holographic and optically variable devices and method for making the same |
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| GB0902000D0 (en) * | 2009-02-09 | 2009-03-11 | Optaglio Sro | Micro-relief structures |
| US20110091691A1 (en) * | 2009-10-16 | 2011-04-21 | Vacumet Corp. | Multiple layer holographic metal flake film and method of manufacturing the same |
| DE102011088154A1 (en) | 2011-12-09 | 2013-06-13 | CFC Europe GmbH | Layered product for coating and substrate used for hologram, has optical structure comprising layer(s) with high refractive nanoparticles and/or layer(s) with low refractive nanoparticles |
| EP2895922B1 (en) * | 2012-09-17 | 2018-04-18 | Basf Se | Security elements and method for their manufacture |
| GB201301790D0 (en) | 2013-02-01 | 2013-03-20 | Rue De Int Ltd | Security devices and methods of manufacture thereof |
| CN105291630B (en) * | 2014-08-01 | 2017-01-25 | 中钞特种防伪科技有限公司 | Optical anti-counterfeiting element and anti-counterfeiting product provided with same |
| DE102016201068A1 (en) * | 2016-01-26 | 2017-07-27 | Dr. Johannes Heidenhain Gmbh | Measuring standard and position measuring device with this material measure |
| WO2017207420A1 (en) * | 2016-06-03 | 2017-12-07 | Stensborg A/S | Method of metallising optical elements comprising surface relief structures |
| US10821765B2 (en) | 2018-01-10 | 2020-11-03 | Assa Abloy Ab | Secure documents and methods of manufacturing the same |
| US10350935B1 (en) | 2018-01-10 | 2019-07-16 | Assa Abloy Ab | Secure document having image established with metal complex ink |
| KR20220010484A (en) | 2019-05-20 | 2022-01-25 | 크레인 앤 코, 인크 | Use of nanoparticles to tune the refractive index of a layer of a polymer matrix to optimize micro-optical (MO) focus |
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| US2839378A (en) * | 1955-04-15 | 1958-06-17 | American Marietta Co | Method of making metal flakes |
| US4116710A (en) * | 1973-10-24 | 1978-09-26 | The Dow Chemical Company | Metallic particulate |
| KR860009325A (en) * | 1985-05-07 | 1986-12-22 | 기다지마 요시도시 | Transparent Hologram |
| US5822092A (en) | 1988-07-18 | 1998-10-13 | Dimensional Arts | System for making a hologram of an image by manipulating object beam characteristics to reflect image data |
| US5189531A (en) * | 1988-10-17 | 1993-02-23 | August DeFazio | Hologram production |
| US5549774A (en) * | 1992-05-11 | 1996-08-27 | Avery Dennison Corporation | Method of enhancing the visibility of diffraction pattern surface embossment |
| JPH0655633A (en) * | 1992-08-11 | 1994-03-01 | Dainippon Printing Co Ltd | High intensity hologram decorative sheet intermediate sheet, and manufacture thereof |
| US5464710A (en) * | 1993-12-10 | 1995-11-07 | Deposition Technologies, Inc. | Enhancement of optically variable images |
| US5706106A (en) | 1995-05-25 | 1998-01-06 | Pennsylvania Pulp And Paper Co. | Graphic works involving holography |
| US5981040A (en) | 1996-10-28 | 1999-11-09 | Dittler Brothers Incorporated | Holographic imaging |
| US6549309B1 (en) | 1998-02-10 | 2003-04-15 | Illinois Tool Works Inc. | Holography apparatus, method and product |
| US6863851B2 (en) * | 1998-10-23 | 2005-03-08 | Avery Dennison Corporation | Process for making angstrom scale and high aspect functional platelets |
| US6468380B1 (en) * | 2000-02-28 | 2002-10-22 | Foilmark, Inc. | Solution coated microembossed images |
| JP4678706B2 (en) | 2001-05-30 | 2011-04-27 | 大日本印刷株式会社 | Volume hologram laminate and volume hologram label |
| JP4121773B2 (en) * | 2002-05-15 | 2008-07-23 | 大日本印刷株式会社 | Anti-counterfeit paper having a light diffraction layer and securities |
| WO2004005425A1 (en) | 2002-07-06 | 2004-01-15 | Merck Patent Gmbh | Flakes comprising non-chiral liquid crystal material |
| CN2574152Y (en) * | 2002-10-16 | 2003-09-17 | 上海朗创光电科技发展有限公司 | Antiforging polymer material film structure |
| JP2004223975A (en) * | 2003-01-27 | 2004-08-12 | Toppan Printing Co Ltd | Antiforgery medium, information displaying medium, antiforgery transfer foil, antiforgery seal and manufacturing method thereof |
-
2004
- 2004-12-03 US US11/004,360 patent/US7982930B2/en not_active Expired - Fee Related
-
2005
- 2005-11-18 MX MX2007006628A patent/MX2007006628A/en active IP Right Grant
- 2005-11-18 WO PCT/IB2005/053819 patent/WO2006059254A1/en active Application Filing
- 2005-11-18 JP JP2007543947A patent/JP2008522237A/en active Pending
- 2005-11-18 CA CA2589364A patent/CA2589364C/en not_active Expired - Fee Related
- 2005-11-18 CN CN2005800455326A patent/CN101095087B/en not_active Expired - Fee Related
- 2005-11-18 KR KR1020077012444A patent/KR101361657B1/en active IP Right Grant
- 2005-11-18 EP EP05807175A patent/EP1817642A1/en not_active Withdrawn
- 2005-11-30 TW TW094142170A patent/TWI337719B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CN101095087B (en) | 2012-10-03 |
| US7982930B2 (en) | 2011-07-19 |
| TW200625189A (en) | 2006-07-16 |
| TWI337719B (en) | 2011-02-21 |
| US20060119912A1 (en) | 2006-06-08 |
| JP2008522237A (en) | 2008-06-26 |
| KR101361657B1 (en) | 2014-02-13 |
| MX2007006628A (en) | 2007-06-28 |
| WO2006059254A1 (en) | 2006-06-08 |
| CN101095087A (en) | 2007-12-26 |
| CA2589364A1 (en) | 2006-06-08 |
| KR20070085650A (en) | 2007-08-27 |
| EP1817642A1 (en) | 2007-08-15 |
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Legal Events
| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20151118 |