Classifications

• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
  • G07D7/12—Visible light, infrared or ultraviolet radiation
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/002—Arrays of reflective systems
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/12—Reflex reflectors
  • G02B5/122—Reflex reflectors cube corner, trihedral or triple reflector type
  • G02B5/124—Reflex reflectors cube corner, trihedral or triple reflector type plural reflecting elements forming part of a unitary plate or sheet
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/12—Reflex reflectors
  • G02B5/126—Reflex reflectors including curved refracting surface
  • G02B5/13—Reflex reflectors including curved refracting surface plural curved refracting elements forming part of a unitary body
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/003—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using security elements

Definitions

• the present invention relates to security elements, in particular those intended to be introduced in security documents.
• “Security document” means a means of payment, such as a bank note, a check or a restaurant ticket, an identity document, such as an identity card, a visa, a passport or a passport. driver's license, a lottery ticket, a ticket or a ticket to cultural or sporting events.
• the security element is a security thread and the object intended to receive the security element is a paper, it may be necessary to improve the adhesion of the security element by using an adhesive covering the security elements. Two opposite major faces of the security element.
• these security elements can not be coated with an adhesive in order to improve the adhesion of the security element within the paper, because the presence of the adhesive reduces or even eliminates the optical effect, making the inoperative optical structure.
• the adhesion of the security element can be improved by exposure to a plasma treatment.
• a plasma treatment is relatively difficult and expensive to implement.
• a security element comprising: preferably an adhesive, a reflective optical structure comprising at least one elementary optical reflective structure having a non-planar reflective surface giving an image of a pattern in at least one observation direction of the security element, or comprising at least two elementary reflective optical structures, preferably of different types, in particular at least one of which is arranged to create a light spot image of a source luminous observation of the security element.
• the security element may comprise elementary reflective optical structures of two different types, the elementary optical reflective structures of a type being arranged in the form of at least one pattern, in particular alphanumeric or graphic.
• Elementary reflective optical structures may have a reflective surface of spherical shape and others of polyhedral shape, in particular pyramidal, with an optionally truncated vertex.
• the elementary reflective optical structures may be of different sizes or shapes, to produce image points of a light source at different distances, for example.
• the reflective optical structure and in particular said at least one elementary optical reflective structure, may be devoid of a reflective material, for example such as glass beads.
• the reflective optical structure may correspond to an optical structure on the non-planar face of which a reflective layer has been applied.
• the light source of observation is for example the sun or an electric lamp, especially a source whose incident rays are parallel or substantially parallel.
• the adhesive when present, facilitates the integration of the security element into the associated article.
• the reflective optical structure may comprise non-planar elementary reflecting surfaces, for example concave or convex, of which a smaller dimension is for example greater than or equal to 20 ⁇ m, for example of the order of 30 ⁇ m.
• the subject of the invention is also a security element comprising: a pattern, an elementary optical reflective structure, for example a non-plane mirror, giving an image of the pattern, at least in a direction of observation of the security element, and advantageously, an adhesive.
• the security element can thus be configured to obtain an enlarged image of the pattern, straight or inverted, according to the laws of geometrical optics.
• the reflective optical structure may comprise a concave, convex or Fresnel lens, a lenticular array or else a resin or varnish print, for example crosslinkable by ultraviolet rays.
• the reflective optical structure may consist of elementary reflective optical structures, including mirrors arranged in a regular pattern, in one or more directions.
• the reflecting surface of the optical structure can be made by metallization of a non-planar surface, which allows to benefit from a continuous reflecting surface, while the embossing of a film of a transparent substrate covered on one side a metal layer would be likely to break the surface of the metal and lead to the formation of unsightly cracks and / or can make the optical structure partially inoperative.
• the aforementioned mirrors may in particular be formed by the metallization of a lenticular array, a non-planar face of the array being preferably metallized after the manufacture of this network, to avoid breaking the metal layer, as explained above.
• the mirror or mirrors may be of different types, for example concave, convex, cylindrical, parabolic, spherical or aspherical. Within the network, all the mirrors can be identical or not.
• the mirrors can also be obtained by producing a Fresnel lens receiving a metallization.
• the mirror or mirrors are concave towards the associated pattern (s) in order to produce an enlarged image of the associated pattern (s), and make it easier to observe the pattern (s), despite their small size.
• the optical structure in particular the elementary reflective optical structure (s), may or may not lie entirely on one and the same side of a transparent substrate, for example a film of a transparent thermoplastic material. for example polyester.
• a transparent substrate for example a film of a transparent thermoplastic material. for example polyester.
• the aforementioned lenticular network may be formed on this substrate, in the same material or not, whether or not reported.
• the lenticular network can be made by printing or embossing.
• the thickness of the substrate is for example between 5 and 100 microns, preferably 20 and 30 microns.
• the substrate may have a constant thickness.
• the thickness of the substrate may optionally be chosen according to the optical structure, for example as a function of the focal length of the mirror, so as to have the desired optical effect, as detailed below.
• a pattern associated with the optical structure may be formed on one side of the substrate, in particular by printing, for example printing by a micro-lithography or soft-printing process.
• the pattern may include a hologram or other diffractive structure.
• the aforementioned lenticular array can be made so that the pattern associated with a mirror is between the substrate and the mirror.
• the thickness of the substrate may not substantially modify the visual result obtained.
• the lenticular array may cover one side of the substrate and the one or more patterns may be formed thereon on the opposite side. In this case, the choice of the thickness of the substrate makes it possible to bring the pattern away from or away from the mirror, and can make it possible to adapt the distance of the pattern to the mirror as a function of the focal length thereof.
• the lenticular array may comprise an array of spherical lenses, for example concave towards the substrate.
• the radius at the apex of a mirror especially when it is concave towards the associated pattern, may be between 30 and 45 ⁇ m.
• the distance between the apex of the mirror and the adjacent face of the substrate is for example between 10 and 20 microns, for example between 14 and 16 microns.
• the pattern associated with the mirror can be entirely located in the concavity of the mirror.
• the diameter of the mirror, at its face adjacent to the substrate is for example between 50 and 70 microns, for example between 58 and 62 microns.
• the security element can be covered, on its two outer faces, with an adhesive, making it possible to improve its adhesion within the object in which the security element is introduced, for example a fibrous paper base.
• the aforementioned substrate may in particular be covered, on its face opposite to (x) mirror (s), an adhesive, advantageously transparent, heat-sealable. This adhesive may be colorless or colored.
• the non-planar reflective surface of the reflective optical structure may also be covered with an adhesive.
• the aforementioned lenticular network may be metallized by a vacuum metallization technique, the metal used being for example aluminum.
• the invention is also concerned with an object, in particular a security document, incorporating a security element as defined above.
• a security document may comprise a paper-based fibrous base and the security element has at least one visually accessible portion, for example extends in windows in this fibrous base.
• the security element may for example be a security thread incorporated into window (s) in the security document.
• the presence of an adhesive covering the two faces of such a security thread, and in particular at the level of the "bridges" (areas where the security thread is covered by fibers of the fibrous base), may make it possible to improve its adhesion within the fibrous base.
• the security element may be intended to be viewed from only one side of the document, the mirror or mirrors or other elementary reflective structures being formed on the side of the substrate opposite the face facing the observer.
• the element of security may include, on a portion of its length, mirrors facing one of the faces of the substrate, and on another portion of its length, mirrors facing the opposite face of the substrate, so as to allow the observation of one or more patterns by reflection of their image on the reflecting surface of the corresponding mirror or mirrors, regardless of the viewing face of the security element.
• Other combinations of optical structures are possible, including the combination of concave and convex spherical mirrors.
• the metallization thickness defining the reflecting surface of the mirror may be sufficient to render the mirror opaque. Alternatively, the thickness is thin enough to give the mirror a semi-reflective character.
• the metal layer may comprise partial demetallizations, for example obtained by performing the metallization through a mask.
• High refractive index layers are composed of high refractive index compounds (HRI) for example such as zinc sulphide. These compounds are used in particular to make holograms.
• HRI high refractive index compounds
• the subject of the invention is also a method of manufacturing a security element, in which: - a pattern is optionally produced, at least one basic optical structure, for example a network, is realized; elementary basic optical structures, possibly associated with the pattern, and metallizing a non-planar surface of said basic optical structure or said network to form a reflective structure, for example a reflecting structure giving an image of a light source observation or possible pattern, including an enlarged image thereof, a reflective surface of the reflecting structure being for example concave to the eventual pattern.
• a pattern is optionally produced, at least one basic optical structure, for example a network, is realized; elementary basic optical structures, possibly associated with the pattern, and metallizing a non-planar surface of said basic optical structure or said network to form a reflective structure, for example a reflecting structure giving an image of a light source observation or possible pattern, including an enlarged image thereof, a reflective surface of the reflecting structure being for example concave to the eventual pattern.
• the metallization can be done by a technique of metallization under vacuum.
• the formation of the basic optical structure, for example of the lens can be done for example by printing in flexography, inkjet, offset or screen printing, for example an ink dot of a transparent polymer. crosslinkable under UV, or by hot embossing a thermoplastic support with a metal matrix etched in the form of a lens, among other possibilities.
• the formation of the basic optical structure may or may not be on the same side of a substrate as the possible pattern, with or without identifying the basic optical structure with respect to the pattern.
• the pattern is for example centered on the optical axis of the basic optical structure.
• a lenticular array comprising a plurality of identical lenses, which are metallized to form a network of non-planar mirrors constituting as many elementary reflective structures.
• the security element may be in the form of a security thread.
• Such a wire is for example coated on its two main faces with an adhesive.
• the security thread may be coated with an adhesive on its side having the reflective optical structure.
• the security element may be intended to be incorporated in mass or window (s) in a security document.
• the security element can be flexible.
• the security element especially in the form of security thread, may have a width greater than or equal to 4 mm, better 5 mm, better still 6 mm, for example between 6 and 8 mm, better still between 6 and 10 mm.
• the security element may in particular have a width less than or equal to 8 mm, better 10 mm.
• the security element, especially in the form of security thread may have a thickness of between 5 and 100 microns, better between 20 and 30 microns.
• the subject of the invention is also a method for authenticating or identifying an object, in which the image, for example of a possible pattern, reflected by the reflecting structure, in particular by a mirror, is observed.
• a security element as defined above, and at least from this observation is determined information concerning the identity or authenticity of the object.
• the aforementioned pattern may be an impression of a light colored ink, for example white, or colored.
• FIG. 1 represents in cross-section an exemplary embodiment of a security element according to the invention
• FIGS. 2A to 2C illustrate steps in the embodiment of the security element of FIG. 1
• FIGS. 6 to 8 illustrate alternative embodiments of security elements made in accordance with the invention
• FIG. 9 is a view similar to FIG.
• FIG. 10 is a top view along X of FIG. 9
• FIG. 11 illustrates a mesh according to which certain elementary reflecting structures may be arranged
• FIG. 12 represents an example of elementary reflective structure
• FIG. 13 represents an example of a pattern that can be realized with the elementary reflecting structures of FIG. 12, FIG. FIG. 15 shows the elementary reflective structure of FIG. 14, according to XV.
• the security element 1 represented in FIG. 1 comprises a substrate 2 of which a main face 3 is covered by one or more patterns 4, for example patterns formed by micro-printing, in particular by a micro-lithography technique or by soft printing. Patterns 4 can be printed with white ink.
• the substrate 2 is for example a transparent film of synthetic material, for example a thermoplastic material, in particular polyester.
• the substrate 2 carries a reflective optical structure comprising a lens array 5 of which only one appears in FIGS. 2A to 2C, these lenses 5 having a face 6, on the opposite side to the substrate 2, which is non-planar, for example substantially shaped. spherical cap, as shown.
• This face 6 is, according to one aspect of the invention, covered by a reflective coating 8, so as to form a non-planar mirror 9 constituting an elementary reflective structure.
• a reflective coating 8 so as to form a non-planar mirror 9 constituting an elementary reflective structure.
• the lenticular network can be formed by coming to cover the pattern 4, as shown in Figure 2B.
• the formation of the lenticular network can be carried out in a manner marked or not with respect to the pattern 4.
• the lenses 5 can for example be formed by a printing technique, for example flexography, inkjet, offset or screen printing, ink dots of a transparent polymer ink, which can be crosslinkable under UV.
• a printing technique for example flexography, inkjet, offset or screen printing, ink dots of a transparent polymer ink, which can be crosslinkable under UV.
• the formation of the lenses can also be done by hot embossing the substrate 2 with a metal matrix engraved in the form of a lenticular array.
• the metal is for example aluminum.
• FIGS. 2B and 2C show that a pattern 4 can be located in the concavity of the corresponding mirror. Since the material in which the lens 5 is made is transparent, the mirror 9 can provide an image of the pattern 4 to an observer 0 observing the security element 1 on the side of the face of the substrate 2 opposite the mirror 9.
• the mirror 9 has a concave reflecting face and the distance d between the face 3 of the substrate 2 and the bottom 11 (also called the vertex) of the concavity of the mirror 9 is for example 15 ⁇ m, for a diameter D at the interface 12 with the substrate 2 of about 60 microns.
• the radius of curvature of the mirror 9 may be about 37.5 microns and the focal length of the mirror is then 18.8 microns.
• the mirror 9 provides an enlarged image of the pattern 4 to the observer 0.
• the pattern 4 is for example a 20 ⁇ m wide print.
• the substrate is, for example, 23 ⁇ m thick
• the security element 1 may be covered on its outer faces with an adhesive 14, transparent at least on the observation side.
• said adhesive may be a heat-activatable adhesive, especially such as a heat-sealable coating or a heat-sealable varnish.
• Such adhesives are particularly advantageous when they are used in processes operating at high temperatures, especially with drying operations commonly used in the field of paper mills.
• Examples of adhesives include an ultraviolet (UV) crosslinkable agent, an adhesive to be irradiated, a pressure-sensitive adhesive (PSA), a varnish with a solvent base, of the polyester type, for example , an adhesive in the aqueous phase, etc.
• an adhesive in the aqueous phase there may be mentioned those known under the following trademarks: Mowilith DC (aqueous dispersion of vinyl acetate homopolymer with particles having a size of 0.3 ⁇ m at 2 .mu.m and glass transition temperature Tg of about 38.degree.
• the pattern 4 being formed by printing on the face 18 of the substrate 2 opposite the mirror 9.
• the pattern 4 may be located at a distance from the top of the mirror larger than its focus, and a real reverse image larger than the pattern is obtained.
• the mirror 9 is made with a reflective surface convex towards the pattern, as illustrated in FIG. 7, which produces a smaller image.
• another optical device for example a magnifying lens, for example of the Fresnel lens type, may be associated with a reflecting mirror so as to enlarge the image produced by the mirror again.
• the image seen by the observer does not come from a printed pattern but consists of all the light spots created at the focal length of each mirror.
• the mirrors 9 can as illustrated, be of different sizes to create light points for example of different size or located at different distances from the eye of the observer.
• FIGS. 9 to 15 show an alternative embodiment in which the image seen by the observer is due to the way in which the light is reflected by a plurality of elementary reflective structures of at least two different types.
• the transparent substrate 2 may comprise on one face a plurality of elementary reflective structures 9a and 9b, of respective different shapes, covered by a layer 8 making it possible to create a reflecting surface, for example a layer of metal .
• the elementary reflective structures 9a are, for example, portions of a sphere as illustrated in FIGS. 14 and 15, of height h, for example between 10 and 20 ⁇ m, for example of the order of 15 ⁇ m, and of diameter ⁇ , for example between 20 and 40 microns, for example of the order of 30 microns.
• the elementary reflective structures 9b are, for example, mirrors of pyramidal or truncated pyramid shape, for example having a square base of side W x or W y , for example between 20 and 40 ⁇ m, for example of the order of 30 ⁇ m. , the largest dimension W x or W y being for example equal to the diameter ⁇ at the reflective base of the elementary structures 9a.
• the elementary reflective structures 9b are for example arranged as the meshs of a grating, as represented in FIG. 11, of pitch W for example equal to ⁇ , for example of the order of 30 ⁇ m.
• the elementary reflective structures 9b may be arranged in patterns, as shown in Figures 13 and 10.
• the elementary reflective structures 9a and 9b may be formed in various ways, for example by printing relief and metallization of these reliefs.
• the security element 1 may be in the form of a security thread, for example intended to be incorporated in windows in a paper 40, as illustrated in FIG.
• the security element 1 extends for example between two opposite edges of the paper.
• the security element may come flush with the surface of the paper by its outer face located on the opposite side of the mirror (s), at a window 30.
• security element 1 is applied as a patch.
• the security element 1 can still be integrated into a package, as shown in FIG. 5, or to a label.
• the patterns may be made other than by printing, for example by demetallizing a metal having a color different from that forming the reflecting surface of the mirror, laser engraving, or using to make the pattern by printing a fluorescent or phosphorescent luminescent ink, thermochrome or photo chrome.
• the metal layers can be replaced by layers of a high refractive index material.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Engineering & Computer Science (AREA)
• Computer Security & Cryptography (AREA)
• Credit Cards Or The Like (AREA)
• Optical Elements Other Than Lenses (AREA)
• Diffracting Gratings Or Hologram Optical Elements (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=41210935

Family Applications (1)

Country Status (6)

Families Citing this family (17)

Family Cites Families (9)

• 2009
  • 2009-03-30 FR FR0951980A patent/FR2943800A1/fr not_active Withdrawn
• 2010
  • 2010-03-30 CA CA2757110A patent/CA2757110A1/fr not_active Abandoned
  • 2010-03-30 WO PCT/IB2010/051382 patent/WO2010113114A2/fr not_active Ceased
  • 2010-03-30 US US13/262,562 patent/US20120105928A1/en not_active Abandoned
  • 2010-03-30 EP EP10714073A patent/EP2414871A2/de not_active Ceased
  • 2010-03-30 BR BRPI1012652A patent/BRPI1012652A2/pt not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events