EP2580068A1

EP2580068A1 - Secure structure

Info

Publication number: EP2580068A1
Application number: EP10776135.5A
Authority: EP
Inventors: Celso Eugenio Monreal Vidal; Serge Henry Wsevolojskoy; Arnaldo Martins Seixas; Léo OBERSTERN
Original assignee: Casa Da Moeda Do Brasil; ArjoWiggins Security SAS
Current assignee: HID Global CID SAS
Priority date: 2010-06-10
Filing date: 2010-06-10
Publication date: 2013-04-17
Anticipated expiration: 2030-06-10
Also published as: TW201228852A; WO2011154764A1; EP2580068B1; CA2800415A1; BR112012031309B1; UY33450A; PL2580068T3; BR112012031309A2

Abstract

A structure, in particular, a secure document such as a passport is provided. The structure includes a first layer (4) comprising a région of modified opacity (40), at least one additional layer (30; 6; 9) fixed relative to the first layer (4), and a luminescent agent (37) positioned relative to the at least one additional layer and the first layer such that upon excitation of the luminescent agent, light produced by the luminescent agent propagates through the first layer to become observable and render features of the région of modified opacity apparent. The région of modified opacity is not visible in light transmitted from any side of the structure.

Description

SECURE STRUCTURE

DESCRIPTION

Field of the Disclosure

[001 ] The present disclosure is related to secure structures, and more particularly, to secure structures incorporating multi-level authentication features, such as passports.

Background of the Disclosure

[002] Authentication of secured structures (e.g., secure documents) is of continuing interest for various purposes, for example, border security. To prevent counterfeiting of documents, various measures have been undertaken including, for example, visual authentication measures. Such visual authentication measures may include providing regions of modified opacity, e.g., watermarks and/or pseudo- watermarks on a document.

[003] EP A 1 122 360 describes creating a screened pale watermark, i.e., a watermark having paler zones (of density per unit area less than that of a velum zone of the sheet).

[004] Additional optical security features have been used in conjunction with watermarks. For example, German Application DE 10 2005 022 518 describes a security paper comprising a watermark and printed ink configured to fluoresce when illuminated by ultra-violet (UV) light. The security paper is transparent to the UV light only in the area of the watermark.

[005] In addition, electronic measures, such as, for example, electronic devices (e.g., electronic chips) have been introduced into security structures to enable higher level authentication of such structures. Such electronic devices may contain information (e.g., RFID) which may be read when special equipment is available for extracting the information stored thereon. For example, U.S. Patent No. 5 949 059 to Rawson describes a label having both visual and electronic authentication means. However, such electronic equipment for verifying such information can be expensive and therefore, difficult to obtain for many authentication authorities.

[006] International Application WO 2007/034129 discloses a passport and methods for manufacturing such a document. Techniques described therein related to manufacture of a passport may be helpful in understanding such manufacture. [007] There exists a need to improve the secure aspects of security structures while maintaining structures that are cost effective and may not require expensive systems for performing authentication.

[008] It is further desirable to enhance redundancy for authentication of security structures, for example, passports.

[009] It is further desirable to improve evidence of attempts at tampering with secure structures.

[010] It is accordingly an object of the present disclosure to provide a secure structure enabling authentication.

SUMMARY OF THE DISCLOSURE

[01 1 ] Embodiments of the present disclosure provide a structure in particular, a secure document such as a passport. The structure includes a first layer comprising a region of modified opacity, at least one additional layer fixed relative to the first layer, and a luminescent agent positioned relative to the at least one additional layer and the first layer such that upon excitation of the luminescent agent, light produced by the luminescent agent propagates through the first layer to become observable and render features (e.g., a design outline and/or pattern) of the region of modified opacity apparent. The region of modified opacity is not visible in light transmitted from any side of the secure structure. The structure is preferably "flexible" which means bendable and/or foldable as for example, credit cards, ID cards, passports, banknotes, tickets, and other security documents.

[012] In creating such a structure, authentication may be enabled where an authority has limited means but believes that a level 2 authentication is sufficient, authentication may be made based solely on observation of the region of modified opacity through illumination with a predetermined form of electromagnetic radiation (e.g., infrared and/or ultraviolet light).

[013] In addition, it may be possible to conceal the existence of the region of modified opacity on the structure, thereby possibly preventing forgers from recognizing what would enable copying of the structure. Moreover, because the first layer may have a reduced thickness within the region of modified opacity, attempts to separate the first layer from the at least one additional layer may result in damage to at least the region of modified opacity, which may be easily identified through illumination of the luminescent agent, thereby providing additional tamper-proofing. [014] The region of modified opacity is preferably a region of reduced opacity. And preferably, the region of reduce opacity superposes the luminescent agent, at least in part.

[015] The luminescent agent may be excitable by at least one of ultraviolet light and infrared light.

[016] The luminescent agent may be disposed upon a secure band. In some embodiments, the secure band may be located between the at least one additional layer and the first layer of material. The secure band is preferably made of fibrous material, preferably paper. The secure band may have a surface area less than a surface area of the at least one additional layer, thereby possibly resulting in cost savings with regard to manufacture of the structure.

[017] In exemplary embodiments of the disclosure, the secure band is partial in the sense that it extends over only a part of the surface area of the at least one additional layer. Under such circumstances, the secure band preferably extends over an area of the at least one additional layer that is sufficient to underlie the region of modified opacity of the first layer.

[018] In exemplary embodiments, the region of modified opacity is sufficiently transparent to allow luminescent light to be transmitted through the first layer upon excitation of the luminescent agent. Particularly, where a region of reduced opacity is implemented, the region may have a maximum depth of about 10 to about 90 percent of the thickness of the first layer.

[019] The region of modified opacity may be a watermark and/or a pseudo- watermark. The region of modified opacity is preferably a region of reduced opacity. The watermark is preferably a pale watermark with recesses on the side of the first layer facing the at least one additional layer. For example, the pale watermark can be a screened watermark as disclosed in EP 1 1 22 360. When the region of modified opacity is of increased opacity, the velum is of sufficient transparency so the features of the region of modified opacity appear (e.g., in negative).

[020] The structure may include a laminate protective layer in contact with the first layer of material.

[021 ] The first layer of material may include a fibrous material, preferably paper. In addition, the at least one additional layer may comprise an opaque layer which may be opaque over its entire surface area. The region of modified opacity may be visible to a naked eye only during periods of luminescent agent excitation. [022] The first layer and the at least one additional layer may all be bonded together, or selected layers may be individually bonded to one another. Bonding may be performed using laminating, for example. The first layer and at least one additional layer may be bonded such that attempted debonding results in damage to the region of modified opacity, for example, by tearing. This may provide evidence of tampering.

[023] At least the first layer preferably includes a security paper. The weight of the paper may for example lie in the range 70 grams per square meter (g/m²) to 1 80 g/m²

[024] Luminescent agents shall mean substances which emit light in response to external stimulation/excitation. For example, luminescent agents may emit light in response to light stimulus (i.e., photoluminescence), ), chemical stimulus (i.e., chemiluminescence), electrical stimulus (i.e., electroluminescence), and/or mechanical stimulus (i.e., triboluminescence).

[025] The luminescent agent is preferably a photoluminescent agent responding to light stimulus, for example ultraviolet (UV) and/or infrared rays, and more particularly, a UV fluorescent agent.

[026] Luminescent agents may include at least one of a luminescent ink, a luminescent fiber, a luminescent pigment, a luminescent flat security element such as a "planchette" and a luminescent binder. For example, luminescent agents could be mixed with an adhesive used when bonding the layers. For example, luminescent agents may be mixed up to 50 percent by dry weight with an adhesive.

[027] The structure may include an electronic device at least partially disposed within the at least one additional layer. The electronic device may be configured to provide information regarding at least one of the structure and the owner of the structure.

[028] The at least one additional layer may comprise a second layer and an intermediate layer.

[029] The electronic device may be, for example, an RFID device. In addition, the electronic device may comprise an antenna at least partially contacting the intermediate layer, the antenna being damaged with attempted debonding of the first layer from another bonded layer. This may provide additional tamper evidence.

[030] The electronic device may be at least partially disposed in the second layer. [031 ] The luminescent agent may be disposed upon the intermediate layer and/or within a material of the intermediate layer.

[032] The first layer and/or the at least one additional layer may comprise a compressible paper, for example, paper such as that disclosed by European Patent Application EP 2 174 270.

[033] The structure is preferably a passport, and includes a passport cover of which the first and at least one additional layer are part of. In addition, the first layer of material may form one of the front page or the back page of the passport cover. The first layer may be initially part of a booklet of pages which is then, for instance, glued to the at least one additional layer to form front page or the back page of the passport cover.

[034] The excitation light may propagate through the region of modified opacity to excite the luminescent agent.

[035] In another embodiment of the present disclosure, a method is provided for manufacturing a structure as described above. The method may include forming a region of modified opacity within the first layer of material, superposing, at least partially, the region of modified opacity over at least a portion of the luminescent agent, and bonding the first layer and the at least one additional layer.

[036] The bonding step may include laminating and/or may include application of an adhesive. The adhesive may include one or more luminescent agents.

[037] At least one additional layer and the first layer of material may be produced at a production site different from the others.

[038] A region of modified opacity may be a design etched or pressed into a fiber layer during fabrication. For example, such a region of modified opacity may be created by creating zones of pulp that are of reduced or increased thickness at the time the fiber layer is being fabricated on a cylinder mold paper machine, with this being achieved by a projecting or setback imprint in the forming fabric of the cylinder mold.

[039] A region of modified opacity may also come from zones in which the fiber layer has been pressed against a flatbed Fourdrinier machine by a watermarking roll that includes region of modified opacity etched in relief, thereby having the effect, while the fiber layer is being formed in the wet portion of the machine, of strongly pressing certain zones of the fiber layer and thus expelling the water contained in the fibers.

[040] A region of modified opacity may be produced in a finished fiber layer by mechanical and/or chemical means by applying certain substances, the design still being visible in transparency. [041 ] For example, a region of modified opacity may be made by placing or printing a composition in determined zones of the fiber layer, which composition modifies the transparency of the fiber layer, in particular in order to provide zones that are pale and zones that are dark, similar to those of a watermark, but without obtaining a result that makes it possible to obtain fineness and variations of shade that are comparable with those of a conventional watermark.

[042] For example, it is possible to make the finished fiber layer more transparent by applying e.g. a generally fatty composition to determined zones thereof, which composition makes the fiber layer more transparent in permanent manner, such as for example a composition made up of oil and a transparent mineral material as described in US patent No. 2 021 141 , or for example a composition in the form of a wax combined with a solvent, as described in US patent No. 1 479 337.

[043] It is also possible to make the finished fiber layer more transparent by locally applying a wax by hot transfer as described in US patent No. 5 1 18 526, a fluid transparentizing composition that is polymerizable under irradiation as described in GB 1 489 084, or a composition based on polyether, aliphatic isocyanate, and alcohol, that is applied by printing, as described in DE 3 920 378.

[044] It is also possible to use a fiber layer including a hot-melt material, such as for example polyethylene, as described in EP 0 203 499, which, under the local action of heat, is subjected to variations of transparency.

[045] The first fiber layer may be made more opaque, while nevertheless not being made completely opaque to luminescent light, by applying an opacifying agent in determined zones to increase the opacity of the fiber layer, e.g. as described in patent application FR 2 353 676. For example, the opacifying agent may be an aqueous suspension of a pigment or of a filler or a solution of a chemical composition, of a colored composition, or of a dye. The agent may be applied on the first layer while fabricating the first layer and before it is removed from the fabric, so that the agent penetrates into the interstices of the sheet and gives rise, after drying, to a modification of the opacity of the sheet for treatment in selected zones. That fabrication technique has the drawbacks of requiring special roll devices for applying the agent, and, for better results, of requiring a suction device to be used in order to cause the agent to penetrate into the interstices of the sheet.

[046] It is also possible to make a region of modified opacity using the method described in the document by W. Walenski, "Watermarks and those that are not", Druckspiegel 52, No. 3: 66-68 (March 1997). That document describes a method of fabricating a pseudo-watermark on non-coated paper, the method including applying a marking piece representing the pattern of the pseudo-watermark with heat and pressure against a sheet of re-wetted paper.

[047] It is also possible to make a region of modified opacity on non-coated paper by applying a re-wetting solution on one or more determined zones of the paper with heat and pressure so as to evaporate the solution and density the paper in the determined zones.

[048] International application WO 97/17493 also describes fabricating coated paper including pseudo-watermarks that result from a varying in the weight of the layer that is applied in determined zones, thereby giving rise to a variation in the thickness and the opacity in these zones where the weight of the coating is reduced or increased.

[049] International application WO 99/014433 also describes another method of fabricating a pseudo-watermark on coated paper, that method involving making an image in the paper after the drying step that follows the last coating operation, by performing steps in which a re-wetting solution is applied to at least one face of the coated paper in one or more determined zones, and pressure and heat are applied in those zone(s) of the coated paper so as to evaporate the solution and densify the coated paper therein relative to the remainder of the paper.

[050] Finally, a region of modified opacity may be made mechanically by making marks by mechanical embossing in determined zones of the fiber layer, as described in patent DE 3 71 8 452.

[051 ] A region of modified opacity may also be made in a polymer layer by applying a composition suitable for modifying its transparency.

[052] Application WO 91 /07285 describes printing a composition on a synthetic medium, which composition modifies the opacity of the support and contains at least one mineral filler and at least one binder and a soluble or pigmentary coloring agent. The composition is applied in determined zones and the medium is subsequently coated over its entire surface with a printable pigmentary composition using coating methods known to the person skilled in the art.

[053] US patent No. 4 307 899 describes an authentication card comprising an imprint formed on a medium, preferably a plastics medium, by printing partially superposed colored layers. The zones printed with a single layer appear pale in transmitted light and dark in reflected light, and the zones printed with a plurality of superposed layers appear dark in transmitted light and pale in reflected light, thereby producing a watermarked effect. By modifying the number of layers, it is possible to obtain multi-tone effects.

[054] A region of modified opacity may also be made in a polymer layer by using mechanical means.

[055] For example, it is possible to make a pseudo-watermark on a sheet of polymer material by passing the sheet between two rolls, one of which carries a recessed or projecting pattern in relief so as to form an impression as described in EP 0 655 316. The sheet is subsequently oriented by being stretched so that in transmitted light the pattern appears in black and white corresponding to the zones that are marked in projection or depression by the roll.

[056] International application WO 2007/016148 also describes a plastics layer suitable for being deformed, in particular stamped by embossing or debossing to form an image that appears like a watermark, and then laminated without the image that has been formed being damaged.

[057] In addition, a region of modified opacity may be made on a polymer layer by using electromagnetic radiation, for example a laser. For example, application EP 1 518 661 describes a method of making a pseudo-watermark on a reeled polymer sheet by electromagnetically irradiating certain zones and by stretching the sheet so to obtain a stretched sheet presenting transparent zones that correspond to the irradiated zones.

[058] A region of modified opacity of the first layer may be made using any of the above-described methods and/or any additional methods known in the art and not described herein.

[059] The at least one additional layer may comprise a single layer or a plurality of layers.

[060] The at least one additional layer may be a fiber layer or may comprise one or more fiber layers. For example, the fiber layer may be based on cellulose fibers, in particular cotton fibers, and/or synthetic fibers such as polyamide and/or polyester fibers, for example. In particular, the intermediate layer may be a translucent tracing paper.

[061 ] The first layer and/or the at least one additional layer may be fiber or polymer layers.

[062] In particular exemplary embodiments of the disclosure, the first layer and/or the at least one additional layer are fiber layers, in particular based on cellulose fibers, in particular cotton fibers, and/or synthetic fibers, such as polyamide and/or polyester fibers, for example. [063] The at least one additional layer may be a polymer layer that has previously been extruded or laminated onto the first and second layer(s), e.g. extruded hot or cold. For example, for the extruded polymer, it is possible to use polyethylene or a mixture of polyethylene and ethylene vinyl acetate.

[064] The at least one additional layer may be assembled with the first and second layers with the help of one or more adhesive layers that are in liquid form or in film form. In a variant, the intermediate layer may be assembled to the first and second layers by melting or welding.

[065] The at least one additional layer may also be or include an adhesive layer, e.g. an adhesive film suitable also for serving to assemble together the first and second layers. The adhesive film may for example be a polyethylene film.

[066] In particular exemplary embodiments, the at least one additional layer may be previously sized on at least one of its faces with an adhesive composition that is sensitive to pressure or reactivatable when hot, the composition being applied cold or hot, in liquid form, by extrusion or by lamination.

[067] In other particular exemplary embodiments, the inside faces of the first and at least one additional layer may be previously sized with an adhesive composition that is sensitive to pressure or reactivatable when hot, the composition being applied cold or hot, in liquid form, by extrusion or by lamination.

[068] The thickness of the at least one additional layer may be different from the thickness of the first layer. The material and/or thickness of the at least one additional layer are preferably chosen such as to constitute an opaque layer for the region of modified opacity to not be visible in transmited light from any side of the secure structure. For instance, the material can be a PVC 50 microns thick or a cellulosic material 150 microns thick. The at least one additional layer may extend over the entire surface area of the first layer.

[069] Additional objects and advantages of the present disclosure will be set forth in part in the description which follows.

[070] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[071 ] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate a number of exemplary features of non-limiting embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure. In the drawings,

[072] Figures 1 A-C are exemplary illustrations of cross-sections of secure structures consistent with embodiments of the present disclosure;

[073] Figure 2 is an exemplary partial cross-section of a cover consistent with embodiments of the present disclosure;

[074] Figures 3A-C are additional exemplary partial cross-sections of a cover consistent with embodiments of the present disclosure;

[075] Figure 4 is yet another exemplary partial exploded cross-section of a cover consistent with embodiments of the present disclosure;

[076] Figure 5 is an exemplary illustration of visual authentication of a secure structure manufactured according to embodiments of the present disclosure;

[077] Figure 6 is a flowchart showing an exemplary method for fabricating a secure structure according to embodiments of the present disclosure; and

[078] Figure 7 is a flowchart showing an exemplary method for authenticating a secure structure according to embodiments of the present disclosure.

[079] Notably, to facilitate understanding of the following description, the thickness of the various structures in the drawings are, unless otherwise specified, not to scale. Thicknesses and other dimensions may be exaggerated or minimized to enable visualization and understanding of various features of the embodiments described herein.

MORE DETAILED DESCRIPTION

[080] Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are provided and illustrated in the

accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[081 ] Figures 1 A-C are exemplary illustrations of a cross-section of a secure structure 1 , consistent with embodiments of the present disclosure. Secure structure 1 may include, as shown in Figure 1 A, a multipage document, such as, a passport having a cover 7, with front page and end page, and pages 35 also named "visa pages". Such passports may include a data page comprising data regarding the holder of the passport as well as providing access to various other security features present on the secure structure 1 . [082] First layer 4 includes one or more regions of modified opacity 40 formed according to techniques described above, which are of any desired shape and size suitable for a particular application. For example, region of modified opacity 40 may resemble a shape of a country issuing a passport document, or particular shapes recognized as associated with an issuing entity of secure structure 1 . Any desirable number of region of modified opacity 40 can be provided on first layer 4, with such region of modified opacity 40 being located at any desirable position on first layer 4. For example, it may be desirable to provide one or more regions of modified opacity 40 aligned to form a particular shape, or in a straight line, or in any other configuration on first layer 4.

[083] Region of modified opacity 40 is preferably located on a bottom surface of first layer 4, so as to face an intermediate layer 30 as shown in the figures. In other words, once assembled with other layers, region of modified opacity 40 is located on an internal portion of first layer 4. When oriented in this way, region of modified opacity 40 may not be apparent on a surface of first layer 4, thereby enabling additional

concealment of region of modified opacity 40. Notably, region of modified opacity 40 is sufficiently transparent to allow luminescent light to be transmitted therethrough during excitation of luminescent agent 37.

[084] First layer 4 interfaces with intermediate layer 30, which in turn is located between first layer 4 and a second layer 6. Intermediate layer 30 may comprise any suitable material, for example, intermediate layer 30 may comprise a fibrous material, a polymeric material, and/or any combination of materials, as desired. According to some embodiments, and as show in Fig. 2, intermediate layer 30 may itself comprise one or more layers of material. Layers comprising intermediate layer 30 may be of like or dissimilar materials, as desired.

[085] According to some embodiments, intermediate layer 30 may comprise a compressible material, e.g., a compressible paper, which enables additional elements to be added between first layer 4 and intermediate layer 30, and/or intermediate layer 30 and/or second layer 6, without substantially increasing a thickness associated with secure structure 1 . Where intermediate layer 30 comprises a paper material, and more particularly, a compressible paper material, the paper material of layer 30 preferably comprises at least 15 percent by weight synthetic fibers and/or at least between 5 and 20 percent by weight of latex instock, such as acrylic. Paper of such composition may be desirable based on its ability to compress with the addition of other elements, thereby limiting or eliminating increases in thickness of the structure with the addition of such elements. For example, where a secure band 45 is implemented, as described in greater detail below, it may be desirable to use such an intermediate layer 30 of compressible material.

[086] Intermediate layer 30 may further be configured to be of substantially similar surface area to that of first layer 4, having such similar length and width portions. Such a configuration enables intermediate layer 30 to substantially align in register with first layer 4.

[087] According to some embodiments of the present disclosure, intermediate layer 30 may comprise a luminescent agent 37, disposed on a surface of intermediate layer 30, and/or interspersed throughout the thickness of intermediate layer 30. For example, where intermediate layer 30 comprises a fibrous material (e.g., paper), luminescent agent 37 may be added to the furnish prior to formation on the wire, and/or at any other suitable time during manufacture. In such embodiments, luminescent agent 37 may be present over substantially the entire surface of intermediate layer, for example, as shown in Fig. 1 C. Alternatively, where luminescent agent 37 is deposited upon intermediate layer 30, particular locations may be selected for such depositing, for example, based on a location of region of modified opacity 40, as shown in Fig. 1 A. Preferably, region of modified opacity 40 superposes luminescent agent 37 at least in part.

[088] Luminescent agent 37 may include, for example, a yellow fluorescent pigment such a Lumilux® D140, supplied by the company HONEYWELL.

[089] It may be desirable to provide at least some of the fibers associated with the fibrous material itself with a luminescent agent 37. Alternatively, luminescent agent 37 may be applied to a surface of intermediate layer 30 following fabrication (e.g., formation on wire and drying), or at any other suitable time as desired.

[090] Figures 1 B and 5 show illustrations of an exemplary embodiment wherein luminescent agent 37 is associated with a secure band 45 either in addition to or in lieu of intermediate layer 30. Such a secure band 45 may comprise any suitable substance (e.g., fibrous, polymer, etc.) and includes luminescent agent 37, among other things. Luminescent agent 37 can be interspersed throughout the thickness of secure band 45 and/or disposed on one or more surfaces of secure band 45. In such embodiments, secure band 45 is configured to be located between first layer 4 and intermediate layer 30 (e.g., in contact with both first layer 4 and intermediate layer 30, so that at least part of secure band 45 underlies at least part of the region of modified opacity 40. [091 ] Secure band 45 has a surface area which is smaller than surface area of first layer 4 and intermediate layer 30. For example, in some embodiments, secure band 45 may have a surface area that is 50 percent or less of surface area associated with first layer 4. According to some embodiments, surface area of secure band 45 may be 25 percent, or 1 0 percent, or even less of the surface area of first layer 4. Such a configuration may result in at least, for example, cost savings during manufacture of secure structure 1 because luminescent agent is only present upon the secure band.

[092] Where secure band 45 is implemented in conjunction with intermediate layer 30 of compressible material, there should preferably be no perceivable increase in thickness at the location of secure band 45. This aids in concealing the secure nature of secure structure 1 and further complicates forgery thereof.

[093] Regardless of the method for including luminescent agent 37 within secure structure 1 (e.g., surface of intermediate layer 30, secure band 45, adhesive between first layer 4 and the remainder of cover 7, etc.) luminescent agent 37 should be located such that at least a portion of luminescent agent 37 directly underlies the one or more region of modified opacity 40 present on first layer 4. In this way, at least a portion of luminescent agent 37 is positioned such that light passing through first layer 4 (e.g., through region of modified opacity 40), impinges upon luminescent agent 37, thereby exciting luminescent agent 37 and causing emission of luminescent light. The luminescent light produced by luminescent agent 37 propagates through the first layer to become observable and thereby renders features (e.g., a design outline or a pattern) of region of modified opacity 40 apparent.

[094] For example, where a secure band 45 is implemented, secure band 45 overlies intermediate layer 30 in a position such that upon placement of first layer 4 in correspondence with intermediate layer 30 and secure band 45, region of modified opacity 40 overlies secure band 45, as shown in Figure 5. Similarly, where secure band 45 is not implemented, luminescent agent 37 may be present on and/or in intermediate layer 30 at positions associated with region of modified opacity 40 of first layer 4.

[095] Intermediate layer 30 may include one or more cavities 52 enabling insertion of at least a portion of electronic device 17. Such cavities 52 may include a through hole or a blind hole suitable for receiving all or portions of electronic device 1 7. For example, a through hole may be formed within intermediate layer 30 into which a portion of electronic device 17 may be at least partially inserted within intermediate layer 30 as shown in Fig. 4. According to some embodiments, a recess 53 may be formed within intermediate layer 30, recess 53 being configured to receive an electronic device

[096] Electronic device 17 may carry its own antenna or an antenna intended to be coupled with an amplifying antenna carried by the inlay.

[097] An antenna 64 associated with electronic device 1 7 may rest upon and/or within portions of intermediate layer 30, second layer 6, or other layers present within secure structure 1 . For example, as shown in Fig. 4 it may be desirable to secure antenna 64 to intermediate layer 30 after insertion of electronic device 17 but prior to assembly of intermediate layer 30 and second layer 6, such that upon bonding between the layers, antenna 64 is also secured within secure structure 1 .

[098] Second layer 6 may be bound, as shown, to an opaque external layer 9 of the passport cover. Such external layer 9 may be a polymeric reinforced layer, for example.

[099] Second layer 6 may comprise a fibrous and/or polymeric substance and may be woven, non-woven, or any combination thereof.

[0100] In some embodiments, second layer 6 may also include one or more cavities 58 configured to receive a portion of electronic device 17, as shown in Figs. 3A, 3C, and 4. For example, a through hole or a blind hole may be provided in second layer 6 to enable receipt of at least a portion of electronic device 17.

[0101 ] In some embodiments, electronic device 17 may be located substantially away from region of modified opacity 40 and luminescent agent 37. Alternatively, for example, where space is limited, electronic device 17 may be located in relative proximity to region of modified opacity 40 and may be partially overlaid thereby.

Additionally, electronic device 17 may be affixed to one or more layers via, for example, adhesive. Such techniques may allow electronic device 1 7 to be installed at numerous points during construction of secure structure 1 .

[0102] According to embodiments of the present disclosure, first layer 4 is fixed relative to second layer 6, and intermediate layer 30 such that any attempt at separation of first layer 4, second layer 6, and or intermediate layer 30 from one another may result in damage to at least region of modified opacity 40 (e.g., tearing as a result of reduced thickness at region of modified opacity 40), and therefore an indication of tampering. Such fixing of first layer 4, second layer 6, and/or intermediate layer 30 may be accomplished, for example, via lamination or other suitable process which results in a fixed alignment of first layer 4, second layer 6, and intermediate layer 30. According to some embodiments, an adhesive is introduced in between each layer resulting in bonding between each of the first layer 4, intermediate layer 30, and second layer 6, respectively. According to such embodiments, and where secure band 45 is

implemented, adhesive may also result in bonding between secure band 45 and first layer 4 and intermediate layer 6.

[0103] Light is prevented from being transmitted at least through secure structure 1 in the areas surrounding region of reduced opacity 40 While it may be possible that light may be transmitted through other areas of secure structure 1 (e.g., at a distance from region of reduced opacity 40 where other security features are present), region of modified opacity 40, and its associated features may not be observed in light transmitted through any side of secure structure 1 (i.e., any light transmitted other than by luminescent agent 37). For example, a secure structure 1 as described above will not reveal region of modified opacity 40 in ambient transmitted light. However, where first layer 4 of secure structure 1 is placed such that light causing excitement of luminescent agent 37 impinges upon luminescent agent 37, by way of transmission through region of modified opacity 40, luminescent agent 37 will become excited, thereby allowing observation of region of modified opacity 40 by way of the light re- emitted by luminescent agent 37.

[0104] As shown at Figure 5, secure structure 1 (e.g., a passport) exposed to light by way of first layer 4, reveals a pattern of region of modified opacity 40 overlying secure band 45 as luminescent agent 37 associated with secure band 45 emits light based on the excitation. Where secure structure 1 is a passport, external side of cover layer 9 prevents light from being transmitted through any portion of secure structure 1 except for light emitted by luminescent agent 37 and transmitted through first layer 4.

[0105] Fig. 6 shows a flow chart showing a method for fabricating a secure structure consistent with embodiments of the present disclosure. Region of modified opacity 40 is formed within and/or upon first layer 4 (step 605). Region of modified opacity 40 may be formed either during formation of first layer 4 or following its fabrication.

[0106] First layer 4 may then be aligned (e.g., superposed) with at least one additional layer such that at least a portion of luminescent agent 37 underlies first layer [0107] Insertion of an electronic device 17, if any, may be performed at any point during assembly of secure structure 1 , for example, during manufacture of the inlay, and may occur at a production location different from that of first layer 4.

[0108] Bonding of intermediate layer 30, and, where present, secure band 45, between the first layer 4 and a second layer 6 may be performed (step 620). Such bonding may be performed by lamination, for example.

[0109] Figure 7 is an exemplary flowchart showing a method for authenticating a secure structure according to embodiments of the present disclosure. A user may first illuminate first layer 4 with an ultraviolet and/or infrared light (step 705). The user may then examine the document to determine whether region of modified opacity 40 and/or features thereof is visible via luminescent light resulting from excitation of luminescent agent 37.

[01 10] Although in the disclosure, light is described as impinging on first layer 4 in order to excite luminescent agent 37, it may be possible, in some embodiments to introduce a waveguide used to direct light from the edge of secure structure 1 to an area where luminescent agent 37 exists. In this way, the region of modified opacity 40 may become visible when light from the waveguide impinges upon the luminescent agents 37.

[01 1 1 ] In addition, while embodiments discussed herein have generally been described with regard to a region of modified opacity having a reduced opacity, according to some embodiments not shown, a region of modified opacity may have an increased opacity. In other words, regions of first layer 4 may have additional material deposited upon first layer 4 thereby creating a "dark watermark." In such embodiments, excitation light may pass through surrounding portions of first layer 4 to impinge upon luminescent agent 37, resulting in emission of luminescent light, for example, where luminescent agent 37 has been provided over an entire surface of intermediate layer 30. The emitted luminescent light may then be visible through first layer 4, and may in turn render features of the dark watermark observable; for example, the outline of the watermark will become apparent, the velum being transparent to the luminescent light but not in the thicker zones of the dark watermark having thickness greater than the velum.

[01 12] Structures manufactured according to embodiments of the present disclosure enable authentication of documents on at least a visual and in some embodiments, an electronic basis. Where electronic means are not available, based on the level of complexity associated with the visual authentication devices alone, an authority can remain confident that documents are authentic using visual authentication alone.

[01 13] Throughout the description, including the claims, the term "comprising a" should be understood as being synonymous with "comprising at least one" unless otherwise stated. In addition, any range set forth in the description, including the claims should be understood as including its end value(s) unless otherwise stated. Specific values for described elements should be understood to be within generally accepted manufacturing or industry tolerances, and any use of the terms "substantially" and/or "approximately" should be understood to mean falling within such generally accepted tolerances. Component ratios throughout the disclosure shall be understood to be by dry weight unless otherwise specified.

[01 14] Where any standards of national, international, or other standards body are referenced (e.g., ISO, etc.), such references are intended to refer to the standard as defined by the national or international standards body as of the priority date of the present specification. Any subsequent substantive changes to such standards are not intended to modify the scope and/or definitions of the present disclosure and/or claims.

[01 15] Although the present disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1 . A structure, in particular, a secure document such as a passport, comprising:

a first layer (4) comprising a region of modified opacity (40);

at least one additional layer (30; 6; 9) fixed relative to the first layer (4) ; and a luminescent agent (37) positioned relative to the at least one additional layer and the first layer such that upon excitation of the luminescent agent, light produced by the luminescent agent propagates through the first layer to become observable and render features of the region of modified opacity apparent,

wherein the region of modified opacity is not visible in light transmitted from any side of the structure.

2. The structure of claim 1 , wherein the region of modified opacity is a region of reduced opacity.

3. The structure according to any of the preceding claims, the luminescent agent being disposed upon a secure band (45) having an surface area less than a surface area of the at least one additional layer.

4. The structure according to any of the preceding claims, comprising an electronic device (17) at least partially disposed within the at least one additional layer.

5. The structure according to any of the preceding claims, wherein the region of modified opacity is a watermark.

6. The structure of the preceding claims, wherein the watermark is a pale watermark with recesses on the side of the first layer facing the at least one additional layer.

7. The structure of any of the preceding claim, the first layer of material comprising a fibrous material, preferably paper.

8. The structure of any of the preceding claims, the region of modified opacity being visible to a naked eye only during periods of luminescent agent excitation.

9. The structure according to any of the preceding claims, wherein the first layer and the at least one additional layer are bonded such that an attempted debonding results in damage to the region of modified opacity.

1 0. The structure of any of the preceding claims, the luminescent agent comprising at least one of a luminescent ink, a luminescent fiber, a luminescent pigment, and a luminescent binder.

1 1 . The structure of any of the preceding claims, wherein the at least one additional layer comprises a second layer and an intermediate layer.

1 2. The structure of claims 4 and 1 1 , the electronic device comprising an antenna at least partially contacting the intermediate layer.

1 3. The structure of any of the preceding claims, wherein an adhesive used to bind the first layer and the at least one additional layer comprises the luminescent agent.

14. The structure according to claims 4 and 1 1 , the electronic device being at least partially disposed in the second layer.

1 5. The structure according to claim 12, the luminescent agent being disposed at least one of directly upon the intermediate layer and within the material of the intermediate layer.

1 6. The structure according to any of the preceding claims, wherein the at least one additional layer comprises a compressible paper.

1 7. The structure according to any of the preceding claims, the structure being a passport, the passport comprising a passport cover of which the first and at least one additional layer are part of.

1 8. The structure according to claim 17, the first layer of material comprising one of the front page and the back page of the passport cover.

1 9. The structure according to any of the preceding claims, wherein the at least one additional layer comprises an opaque layer.

20. The structure according to any of the preceding claims, wherein excitation light propagates through the region of modified opacity.

21 . The structure according to any of the preceding claims, the first layer having a weight of between about 70 g/m² and 180 g/m².

22. The structure according to any of the preceding claims, the luminescent agent being mixed with an adhesive in an amount up to about 50 percent by dry weight.

23. A method for manufacturing the structure of any of the preceding claims, comprising:

forming a region of modified opacity within the first layer of material ;

superposing, at least partially, the region of modified opacity over at least a portion of the luminescent agent; and

bonding the first layer and the at least one additional layer.

24. The method according to claim 23, wherein the at least one additional layer and the first layer of material are produced at a production site different from the others.

25. A method for authenticating a structure of any of claims 1 -20, comprising: illuminating the luminescent agent with excitation light outside the visible spectrum;

inspecting the first layer (4) during the illumination to determine whether features of the region of modified opacity is observable based on visible light produced by excitation of the luminescent agent.