WO1995014954A1 - Diffractive indicia for a surface - Google Patents

Diffractive indicia for a surface Download PDF

Info

Publication number
WO1995014954A1
WO1995014954A1 PCT/AU1994/000723 AU9400723W WO9514954A1 WO 1995014954 A1 WO1995014954 A1 WO 1995014954A1 AU 9400723 W AU9400723 W AU 9400723W WO 9514954 A1 WO9514954 A1 WO 9514954A1
Authority
WO
WIPO (PCT)
Prior art keywords
diffractive
indicia
different
elements
ink
Prior art date
Application number
PCT/AU1994/000723
Other languages
French (fr)
Inventor
Robert Arthur Lee
Original Assignee
Commonwealth Scientific And Industrial Research Organisation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commonwealth Scientific And Industrial Research Organisation filed Critical Commonwealth Scientific And Industrial Research Organisation
Priority to AU10591/95A priority Critical patent/AU674805B2/en
Priority to EP95901280A priority patent/EP0730753A4/en
Priority to CA002173838A priority patent/CA2173838A1/en
Priority to JP7514697A priority patent/JPH09506442A/en
Priority to US08/624,536 priority patent/US5912767A/en
Publication of WO1995014954A1 publication Critical patent/WO1995014954A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B44—DECORATIVE ARTS
    • B44F—SPECIAL DESIGNS OR PICTURES
    • B44F1/00—Designs or pictures characterised by special or unusual light effects
    • B44F1/08—Designs or pictures characterised by special or unusual light effects characterised by colour effects
    • B44F1/14—Iridescent effects
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
    • B41M3/12—Transfer pictures or the like, e.g. decalcomanias
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
    • B41M3/14—Security printing
    • B41M3/148—Transitory images, i.e. images only visible from certain viewing angles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B44—DECORATIVE ARTS
    • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
    • B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
    • B44C1/10—Applying flat materials, e.g. leaflets, pieces of fabrics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B44—DECORATIVE ARTS
    • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
    • B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
    • B44C1/16—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like
    • B44C1/165—Processes, not specifically provided for elsewhere, for producing decorative surface effects for applying transfer pictures or the like for decalcomanias; sheet material therefor
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1828—Diffraction gratings having means for producing variable diffraction
    • 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
    • G03H2230/00—Form or shape of the hologram when not registered to the substrate
    • G03H2230/10—Microhologram not registered to the substrate
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S283/00—Printed matter
    • Y10S283/902—Anti-photocopy

Definitions

  • This invention relates to diffractive indicia for a surface. It relates particularly to optically variable inks and optically variable elements which appear to change colour when the viewing angle and/or the angle of illumination is varied.
  • An important feature of several documents such as bank notes, credit cards, cheques and share certificates, is that they be difficult to reproduce by way of forgery. Because the range of available reproduction equipment and techniques is constantly improving, there is a continuing need for more and better anti-forgery security techniques.
  • One such anti-forgery security technique involves using indicia which incorporate optical variability.
  • An optically variable document has an appearance which changes when the viewing angle and/or the angle of illumination changes.
  • optically variable device is the hologram diffractive device commonly used on credit cards.
  • a less well known type of security device is a colour switching ink provided by Sicpa Holding SA.
  • Sicpa Holding SA After the ink has been applied to the surface of a document, it appears to be green when viewed from particular angles relative to a light source, and red when viewed from other angles, so that particular movements in viewing angle, lighting direction or document orientation result in a colour switch effect from green to red or red to green.
  • the colour switching Sicpa ink comprises a large number of small multi-layer interference elements. The layers have different refractive indices, and partial reflection occurs at the interface between each layer.
  • the layer thicknesses, refractive indices and degrees of reflectiveness are chosen such that an optical interference effect occurs between the layers such that, for a given illumination direction, red light is reflected in a particular range of directions and green light is reflected in another range of directions.
  • the colour switching ink provides an effective security device, but it is very difficult to make the multi-layer interference elements, and consequently, the ink is very expensive.
  • each diffractive element has a diffractive surface relief structure; the diffractive elements, when applied to the surface, are not separately resolvable to the human eye; and the appearance of the diffractive indicia, when applied to the surface, changes when the viewing angle and/or angle of illumination relative to the surface changes.
  • the diffractive indicia are incorporated in an ink, with the diffractive elements dispersed throughout the ink, the means for adhering is an ink binder which fixes the diffractive elements on the surface as the ink dries.
  • the ink binder may be any suitable binding agent.
  • An ink is typically in the form of a liquid or a paste having a relatively volatile solvent which evaporates after the ink has been applied to the surface of a document.
  • Ink also typically includes one or more colouring substances and a binding agent, which fixes the colouring substances in position on the document as the solvent evaporates.
  • the diffractive elements may be of any suitable shape and configuration.
  • Each element has a surface which is embossed with a diffracting surface structure, and it is preferred although not essential that each element be in the form of an embossed foil, arranged such that the embossed surface structure is the same on both sides. It is further preferred that the diffraction elements be substantially disc-shaped, although they may be of any suitable shape including square, triangular, rectangular, hexagonal and irregularly shaped.
  • the diffractive elements may be of any suitable size. It is preferred that the diffractive elements have linear dimensions of 30 micron or less, most preferably with linear dimensions of the order of 10 micron. A smaller size allows greater dispersion throughout the ink, but also reduces the scope for variability of surface structure.
  • the diffractive elements may be in a range of different sizes, with smaller sizes typically providing less intense diffractive effects and larger sizes typically providing more intense effects.
  • the diffracting surface structure on each diffractive element may have any suitable shape, configuration and orientation. It may consist of grooves, pits, geometrically shaped indentations, or any combination of these. However, a straight line grating diffracts only in particular directions relative to the angle of illumination, whereas it is preferred for the purposes of the present invention that the diffractive effect be observable from any direction, so it is preferred that the diffracting structure be such as to cause diffraction in numerous different directions at the same time, and it is especially preferred that the diffracting structure comprise substantially concentric circular grooves. Other suitable structures include polygonal indentations arranged in substantially concentric circular patterns, and substantially concentric regular polygonal grooves.
  • the spacing between adjacent grooves or indentations on the diffracting surface structures be modulated and/or of different spatial-frequences. Modulation may be used to achieve a two-colour switching effect of the type provided by the Sicpa ink, or it may be used to achieve various other effects such as differences in intensity when viewed from different viewing angles. It is preferred that the ink be substantially transparent, apart from the diffraction elements; however, for some applications it may be desirable to have a degree of colouring in the ink. It is preferred that the diffraction elements have a high density distribution throughout the ink, resulting in a high colour intensity in the ink once it has been applied to a document.
  • the characteristics of the ink binder be such that it permits and assists the diffraction elements to be laid substantially flat against the surface of the document to which the ink has been applied, as the ink dries. Such orientation of the diffraction elements optimizes the diffraction effects observable in the ink.
  • a palette of different optically variable inks is provided. Each ink in the palette has a different characteristic optically variable element, with the result that each ink in the palette produces a different diffractive colour effect when the ink has been applied to a surface.
  • the palette of inks can be used to create an image which is multi-coloured and optically variable over a range of viewing angles.
  • the diffractive indicia are included on a transfer medium, which can be used to transfer them onto a surface.
  • the transfer medium comprises a substrate on which the diffractive indicia are arranged, whereby the diffractive indicia can be applied from the transfer medium onto the surface by pressing portions of the transfer medium against the surface.
  • the transfer medium is analogous to a multi-colour ribbon in a typewriter or impact printer.
  • a four-colour printer ribbon typically has its four colours arranged in four longitudinal strips. The print head is moved to the desired position for printing a character, the ribbon is moved up or down to select the desired colour, and the print head strikes the ribbon to transfer the coloured character to the surface being printed. The print head then moves on to the next position and the process is repeated.
  • Each colour on a multi-colour printer ribbon is analogous to one of the different types of optically variable diffractive elements on the transfer medium.
  • optically variable elements can be "printed" onto a surface by means of a
  • optically variable diffractive elements used in the transfer medium may have any of the characteristics of the elements used in the ink of the present invention as described above.
  • the optically variable diffractive elements may be attached to the substrate in any suitable manner.
  • One suitable manner is by use of an adhesive.
  • Another suitable manner is electrostatic attraction, or by a hot stamping process.
  • the substrate itself may be comprised of the optically variable elements, so that they are applied to the surface by being "punched out" of the transfer medium.
  • the optically variable elements may be caused to adhere to the surface in any suitable manner.
  • One suitable manner is by adhesion; another is by heat sealing.
  • the transfer medium may have any suitable shape and configuration.
  • One suitable configuration is a tape, with the optically variable diffraction elements arranged in longitudinal strips along the length of the tape, each strip containing a plurality of elements of a single type.
  • Another suitable configuration is a disc, with the optically variable elements arranged in sectors, each sector containing elements of a single type. It will be appreciated that the number of different possible configurations is unlimited.
  • Figure 1 is ⁇ a schematic view of a surface bearing diffractive indicia according to the present invention.
  • Figures 2 to 7 are computer generated illustrations of diffracting surface structures suitable for optically variable diffractive indicia according to the present invention.
  • the diffractive indicia of the invention comprise a plurality of small separate diffractive elements 2, shown in Figure 1 as being applied to a surface 1.
  • the diffractive indicia also comprise means for adhering diffractive elements 2 to surface 1.
  • Each diffractive element 2 has a diffractive surface relief structure. Examples of surface relief structures are discussed below with reference to Figures 2 to 7, Diffractive elements 2, when applied to surface 1 , are not separately resolvable to the human eye. The appearance of the diffractive indicia on surface 1 changes when the viewing angle and/or angle of illumination relative to surface 1 changes. Diffractive elements 2 are made from an embossed foil and have an embossed surface sturcture which is the same on both sides. As shown in Figure 1 , a number of different diffractive elements are provided. The different types are selected from a palette of a number of different modulation typesr different spatial frequency types or different sizes with fixed spatial frequency.
  • Each of areas 3, 4, 5, 6 and 7 on surface 1 is filled with a single type of diffractive element, giving that area a distinct appearance which, depending upon the modulation effect used, may appear to have one colour when viewed from one range of directions and another colour when viewed from another range of directions. Different areas may also appear to have different intensities, on account of different sizes of diffractive elements.
  • the diffractive elements 2 may be "printed" on surface 1 in such a way that one "picture" or pattern of areas is observable from one range of viewing angles and a different "picture” or pattern of areas is observable from a different range of viewing angles. This "picture-switch" effect can be achieved through the use of .diffractive elements having different spatial frequencies.
  • a diffractive element with a given spatial frequency Under given illumination conditions, a diffractive element with a given spatial frequency generates diffractive effects which are observable from particular viewing angles. A diffractive element with a different spatial frequency under the same illumination conditions generates diffractive effects which are observable from different viewing angles. Accordingly, a "picture-switch” effect can be created on a surface by "printing" a first "picture” using diffractive elements of a first average spatial frequency and “overprinting" the surface with a second "picture” using diffractive elements of a second average spatial frequency. The image observed will switch between the first "picture” and the second "picture” as viewing angle is changed.
  • Figure 2 illustrates a regular concentric circular groove pattern.
  • the spacing between grooves is preferably of the order of 0.4 to 0.6 micron.
  • the groove pattern is embossed into one surface of a thin piece of foil, so a similar groove pattern occurs on the opposite surface. Because the pattern illustrated in Figure 2 is unmodulated, when the diffracting surface structure is illuminated from a particular direction, diffracted light ranging through the spectrum from blue through to red will be observable around the diffraction element.
  • grooves are illustrated as being continuous, this is not essential, and the surface structure may instead be made from discontinuous arcs, short straight lines or geometrical shapes, all arranged in a broadly concentric circular configuration.
  • Figure 3 shows another type of modulation suitable for use in the diffracting surface structure.
  • ⁇ has a value of 0.03.
  • Figure 5 is a computer plot of another modulated concentric circle diffracting surface structure configuration.
  • Figure 7 shows yet another modulated concentric circular groove configuration.
  • modulation functions illustrated in Figures 2 to 7 are examples only, and it is to be understood that numerous other modulation functions can usefully be applied.
  • the preferred surface structure is shown as having a concentric circular configuration, it is not essential that the diffractive elements themselves have a circular shape, and they may be square, rectangular, triangular, or any other shape including irregularly shaped without substantially altering the effect of the modulated concentric circular surface structure.
  • the invention be used in the form of a palette of different "coloured” inks, each having its own characteristic type of diffractive element, or in the form of a transfer medium having several different regions, each having its own characteristic type of diffractive elements.
  • the "colours" are varied between different coloured inks by varying the parameters a (the inter-groove spacing) and B (the modulation factor) in the diffracting elements.
  • the use of several different "coloured” inks enables the production of multi-coloured diffractive images which are optically variable over a range of viewing angles. It is to be understood that various alterations, additions and/or modifications may be made to the parts previously described without departing from the ambit of the invention.

Abstract

Diffractive indicia for a surface (1) comprising a plurality of small separate diffractive elements (2) and means for adhering the diffractive elements to the surface. Each diffractive element has a diffractive surface relief structure and is not separately resolvable to the human eye. The appearance of the diffractive indicia, when applied to the surface, changes when the viewing angle and/or angle of ilumination relative to the surface changes. In preferred arrangements, the diffractive indicia are incorporated in an ink or a transfer medium. A palette of diffractive indicia with different characteristic colours and other optical properties may be provided.

Description

DIFFRACTIVE INDICIA FOR A SURFACE
This invention relates to diffractive indicia for a surface. It relates particularly to optically variable inks and optically variable elements which appear to change colour when the viewing angle and/or the angle of illumination is varied. An important feature of several documents such as bank notes, credit cards, cheques and share certificates, is that they be difficult to reproduce by way of forgery. Because the range of available reproduction equipment and techniques is constantly improving, there is a continuing need for more and better anti-forgery security techniques. One such anti-forgery security technique involves using indicia which incorporate optical variability. An optically variable document has an appearance which changes when the viewing angle and/or the angle of illumination changes. It is easy for a forger to reproduce a document which contains optically invariable images, but it is extremely difficult for a forger to incorporate optical variability into a reproduced document. One well known ezample of an optically variable device is the hologram diffractive device commonly used on credit cards.
A less well known type of security device is a colour switching ink provided by Sicpa Holding SA. After the ink has been applied to the surface of a document, it appears to be green when viewed from particular angles relative to a light source, and red when viewed from other angles, so that particular movements in viewing angle, lighting direction or document orientation result in a colour switch effect from green to red or red to green. It is believed that the colour switching Sicpa ink comprises a large number of small multi-layer interference elements. The layers have different refractive indices, and partial reflection occurs at the interface between each layer. The layer thicknesses, refractive indices and degrees of reflectiveness are chosen such that an optical interference effect occurs between the layers such that, for a given illumination direction, red light is reflected in a particular range of directions and green light is reflected in another range of directions. The colour switching ink provides an effective security device, but it is very difficult to make the multi-layer interference elements, and consequently, the ink is very expensive. - - According to the present invention, there are provided diffractive indicia for a surface, comprising:
(a) a plurality of small separate diffractive elements, and
(b) means for adhering the diffractive elements to the surface wherein: each diffractive element has a diffractive surface relief structure; the diffractive elements, when applied to the surface, are not separately resolvable to the human eye; and the appearance of the diffractive indicia, when applied to the surface, changes when the viewing angle and/or angle of illumination relative to the surface changes.
In one preferred aspect of the invention, the diffractive indicia are incorporated in an ink, with the diffractive elements dispersed throughout the ink, the means for adhering is an ink binder which fixes the diffractive elements on the surface as the ink dries. The ink binder may be any suitable binding agent. An ink is typically in the form of a liquid or a paste having a relatively volatile solvent which evaporates after the ink has been applied to the surface of a document. Ink also typically includes one or more colouring substances and a binding agent, which fixes the colouring substances in position on the document as the solvent evaporates. The diffractive elements may be of any suitable shape and configuration.
Each element has a surface which is embossed with a diffracting surface structure, and it is preferred although not essential that each element be in the form of an embossed foil, arranged such that the embossed surface structure is the same on both sides. It is further preferred that the diffraction elements be substantially disc-shaped, although they may be of any suitable shape including square, triangular, rectangular, hexagonal and irregularly shaped.
The diffractive elements may be of any suitable size. It is preferred that the diffractive elements have linear dimensions of 30 micron or less, most preferably with linear dimensions of the order of 10 micron. A smaller size allows greater dispersion throughout the ink, but also reduces the scope for variability of surface structure. The diffractive elements may be in a range of different sizes, with smaller sizes typically providing less intense diffractive effects and larger sizes typically providing more intense effects.
The diffracting surface structure on each diffractive element may have any suitable shape, configuration and orientation. It may consist of grooves, pits, geometrically shaped indentations, or any combination of these. However, a straight line grating diffracts only in particular directions relative to the angle of illumination, whereas it is preferred for the purposes of the present invention that the diffractive effect be observable from any direction, so it is preferred that the diffracting structure be such as to cause diffraction in numerous different directions at the same time, and it is especially preferred that the diffracting structure comprise substantially concentric circular grooves. Other suitable structures include polygonal indentations arranged in substantially concentric circular patterns, and substantially concentric regular polygonal grooves.
In order to achieve particular optical effects, it is preferred that the spacing between adjacent grooves or indentations on the diffracting surface structures be modulated and/or of different spatial-frequences. Modulation may be used to achieve a two-colour switching effect of the type provided by the Sicpa ink, or it may be used to achieve various other effects such as differences in intensity when viewed from different viewing angles. It is preferred that the ink be substantially transparent, apart from the diffraction elements; however, for some applications it may be desirable to have a degree of colouring in the ink. It is preferred that the diffraction elements have a high density distribution throughout the ink, resulting in a high colour intensity in the ink once it has been applied to a document. It is preferred that the characteristics of the ink binder be such that it permits and assists the diffraction elements to be laid substantially flat against the surface of the document to which the ink has been applied, as the ink dries. Such orientation of the diffraction elements optimizes the diffraction effects observable in the ink. In a preferred application of the invention, a palette of different optically variable inks is provided. Each ink in the palette has a different characteristic optically variable element, with the result that each ink in the palette produces a different diffractive colour effect when the ink has been applied to a surface. The palette of inks can be used to create an image which is multi-coloured and optically variable over a range of viewing angles.
In another aspect of the invention, the diffractive indicia are included on a transfer medium, which can be used to transfer them onto a surface. The transfer medium comprises a substrate on which the diffractive indicia are arranged, whereby the diffractive indicia can be applied from the transfer medium onto the surface by pressing portions of the transfer medium against the surface.
The transfer medium is analogous to a multi-colour ribbon in a typewriter or impact printer. A four-colour printer ribbon, for example, typically has its four colours arranged in four longitudinal strips. The print head is moved to the desired position for printing a character, the ribbon is moved up or down to select the desired colour, and the print head strikes the ribbon to transfer the coloured character to the surface being printed. The print head then moves on to the next position and the process is repeated.
Each colour on a multi-colour printer ribbon is analogous to one of the different types of optically variable diffractive elements on the transfer medium.
The optically variable elements can be "printed" onto a surface by means of a
"print head" pressing a region of the transfer medium which has optically variable elements of the desired "colour" against the surface.
The optically variable diffractive elements used in the transfer medium may have any of the characteristics of the elements used in the ink of the present invention as described above.
The optically variable diffractive elements may be attached to the substrate in any suitable manner. One suitable manner is by use of an adhesive. Another suitable manner is electrostatic attraction, or by a hot stamping process.
Another suitable manner is temporary heat bonding. In another suitable arrangement, the substrate itself may be comprised of the optically variable elements, so that they are applied to the surface by being "punched out" of the transfer medium. The optically variable elements may be caused to adhere to the surface in any suitable manner. One suitable manner is by adhesion; another is by heat sealing.
The transfer medium may have any suitable shape and configuration. One suitable configuration is a tape, with the optically variable diffraction elements arranged in longitudinal strips along the length of the tape, each strip containing a plurality of elements of a single type. Another suitable configuration is a disc, with the optically variable elements arranged in sectors, each sector containing elements of a single type. It will be appreciated that the number of different possible configurations is unlimited.
The invention will hereinafter be described in greater detail by reference to the attached drawings which show example forms of the invention. It is to be understood that the particularity of those drawings does not supersede the generality of the preceding description of the invention. Figure 1 is^ a schematic view of a surface bearing diffractive indicia according to the present invention.
Figures 2 to 7 are computer generated illustrations of diffracting surface structures suitable for optically variable diffractive indicia according to the present invention. The diffractive indicia of the invention comprise a plurality of small separate diffractive elements 2, shown in Figure 1 as being applied to a surface 1. The diffractive indicia also comprise means for adhering diffractive elements 2 to surface 1.
Each diffractive element 2 has a diffractive surface relief structure. Examples of surface relief structures are discussed below with reference to Figures 2 to 7, Diffractive elements 2, when applied to surface 1 , are not separately resolvable to the human eye. The appearance of the diffractive indicia on surface 1 changes when the viewing angle and/or angle of illumination relative to surface 1 changes. Diffractive elements 2 are made from an embossed foil and have an embossed surface sturcture which is the same on both sides. As shown in Figure 1 , a number of different diffractive elements are provided. The different types are selected from a palette of a number of different modulation typesr different spatial frequency types or different sizes with fixed spatial frequency. Each of areas 3, 4, 5, 6 and 7 on surface 1 is filled with a single type of diffractive element, giving that area a distinct appearance which, depending upon the modulation effect used, may appear to have one colour when viewed from one range of directions and another colour when viewed from another range of directions. Different areas may also appear to have different intensities, on account of different sizes of diffractive elements. The diffractive elements 2 may be "printed" on surface 1 in such a way that one "picture" or pattern of areas is observable from one range of viewing angles and a different "picture" or pattern of areas is observable from a different range of viewing angles. This "picture-switch" effect can be achieved through the use of .diffractive elements having different spatial frequencies. Under given illumination conditions, a diffractive element with a given spatial frequency generates diffractive effects which are observable from particular viewing angles. A diffractive element with a different spatial frequency under the same illumination conditions generates diffractive effects which are observable from different viewing angles. Accordingly, a "picture-switch" effect can be created on a surface by "printing" a first "picture" using diffractive elements of a first average spatial frequency and "overprinting" the surface with a second "picture" using diffractive elements of a second average spatial frequency. The image observed will switch between the first "picture" and the second "picture" as viewing angle is changed.
Figure 2 illustrates a regular concentric circular groove pattern. The spacing between grooves is preferably of the order of 0.4 to 0.6 micron. The groove pattern is embossed into one surface of a thin piece of foil, so a similar groove pattern occurs on the opposite surface. Because the pattern illustrated in Figure 2 is unmodulated, when the diffracting surface structure is illuminated from a particular direction, diffracted light ranging through the spectrum from blue through to red will be observable around the diffraction element.
Although the grooves are illustrated as being continuous, this is not essential, and the surface structure may instead be made from discontinuous arcs, short straight lines or geometrical shapes, all arranged in a broadly concentric circular configuration.
Figure 3 is a computer plot of a concentric circular groove configuration, with the inter-groove spacing being modulated according to the formula: r' = Vm, wherein r' is the radius of a circular groove and m is the groove index number.
Figure 3 shows another type of modulation suitable for use in the diffracting surface structure. The modulation illustrated in Figure 3 is given by the general equation: r' = ma + β sin Q2πm n n where m is the groove index number, n is the total number of grooves, β is a modulation factor which relates to the intensity of colour, a is the distance between grooves and Q is the number of cycles of modulation. In the example illustrated, β has a value of 0.03.
Figure 5 is a computer plot of another modulated concentric circle diffracting surface structure configuration. The modulation factor in this instance is given by the equation: r' = m + β cos 2πm n and once again in this case, B has a value of 0.03.
The modulation equation relating to the groove pattern depicted in Figure 6 is as follows: r' = m + βe sin 2πm n n where B has a value of 0.03.
Figure 7 shows yet another modulated concentric circular groove configuration. In this instance, the modulation function is as follows: r' = m + β cos 2πm n n where B has a value of 0.03.
The modulation functions illustrated in Figures 2 to 7 are examples only, and it is to be understood that numerous other modulation functions can usefully be applied. Although the preferred surface structure is shown as having a concentric circular configuration, it is not essential that the diffractive elements themselves have a circular shape, and they may be square, rectangular, triangular, or any other shape including irregularly shaped without substantially altering the effect of the modulated concentric circular surface structure.
As stated previously, it is preferred that the invention be used in the form of a palette of different "coloured" inks, each having its own characteristic type of diffractive element, or in the form of a transfer medium having several different regions, each having its own characteristic type of diffractive elements. In both cases the "colours" are varied between different coloured inks by varying the parameters a (the inter-groove spacing) and B (the modulation factor) in the diffracting elements. The use of several different "coloured" inks enables the production of multi-coloured diffractive images which are optically variable over a range of viewing angles. It is to be understood that various alterations, additions and/or modifications may be made to the parts previously described without departing from the ambit of the invention.

Claims

CLAIMS:
1. Diffractive indicia for a surface, comprising:
(a) a plurality of small separate diffractive elements, and
(b) means for adhering the diffractive elements to the surface wherein: each diffractive element has a diffractive surface relief structure; the diffractive elements, when applied to the surface, are not separately resolvable to the human eye; and the appearance of the diffractive indicia, when applied to the surface, changes when the viewing angle and/or angle of illumination relative to the surface changes.
2. Diffractive indicia according to claim 1 wherein the diffractive elements are made from an embossed foil.
3. Diffractive indicia according to claim 2 wherein the diffractive elements have an embossed surface structure which is the same on both sides.
4. Diffractive indicia according to any one of claims 1 to 3 wherein the diffractive surface relief structure is substantially concentric in configuration.
5. Diffractive indicia according to any one of claims 1 to 4 wherein the spacing between indentations or protrusions on the diffractive surface relief structure of diffractive elements is modulated.
6. Diffractive indicia according to claim 5 wherein the modulation is such that the indicia appear to have one colour when viewed from one range of viewing and illumination conditions and another colour when viewed from another range of viewing and illumination conditions.
7. Diffractive indicia according to claim 6 wherein a palette of a number of different modulation types is provided, such that, when diffractive elements of different modulation types are applied separately to different areas of the surface, the surface appears to have a particular pattern of colours from one range of viewing and illumination conditions and the same pattern but different colours when viewed from another range of viewing and illumination conditions.
8. Diffractive indicia according to any one of claims 1 to 4 wherein a palette of a number of different spatial frequency types is provided such that, when diffractive elements of different spatial frequency types are applied separately to different areas of the surface, the different surface areas generate diffractive effects which are observable from different ranges of viewing and illumination conditions.
9. Diffractive indicia according to any one of claims 1 to 8 wherein a palette of a number of different diffractive element sizes is provided, such that, when diffractive elements of different sizes are applied separately to different areas of the surface, the intensity of light diffracted varies from surface area to surface area.
10. An ink incorporating diffractive indicia according to any one of claims 1 to 9 wherein: the diffractive elements are dispersed throughout the ink; and the means for adhering is an ink binder which fixes the diffractive elements on the surface as the ink dries.
11. An ink according to claim 10 wherein, apart from the diffractive elements, the ink is substantially transparent.
12. A transfer medium, for transferring diffractive indicia according to any one of claims 1 to 9 onto a surface, wherein the transfer medium comprises a substrate onto which the diffractive indicia are arranged, whereby the diffractive indicia can be transferred from the transfer medium onto the surface by pressing portions of the transfer medium against the surface.
13. A transfer medium according to claim 12 wherein a plurality of each of a predetermined number of different types of diffractive indicia are arranged in an ordered manner on the substrate.
14. A transfer medium, for transferring diffractive indicia according to any one of claims 1 to 9 onto a surface, wherein the transfer medium comprises an array of diffractive indicia removably linked together, whereby selected ones of the diffractive indicia can be transferred onto the surface by pressing portions of the transfer medium against the surface.
PCT/AU1994/000723 1993-11-23 1994-11-23 Diffractive indicia for a surface WO1995014954A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
AU10591/95A AU674805B2 (en) 1993-11-23 1994-11-23 Diffractive indicia for a surface
EP95901280A EP0730753A4 (en) 1993-11-23 1994-11-23 Diffractive indicia for a surface
CA002173838A CA2173838A1 (en) 1993-11-23 1994-11-23 Diffractive indicia for a surface
JP7514697A JPH09506442A (en) 1993-11-23 1994-11-23 Diffraction mark for surface
US08/624,536 US5912767A (en) 1993-11-23 1994-11-23 Diffractive indicia for a surface

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPM2572 1993-11-23
AUPM257293 1993-11-23

Publications (1)

Publication Number Publication Date
WO1995014954A1 true WO1995014954A1 (en) 1995-06-01

Family

ID=3777373

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1994/000723 WO1995014954A1 (en) 1993-11-23 1994-11-23 Diffractive indicia for a surface

Country Status (6)

Country Link
US (1) US5912767A (en)
EP (1) EP0730753A4 (en)
JP (1) JPH09506442A (en)
CA (1) CA2173838A1 (en)
TW (1) TW265421B (en)
WO (1) WO1995014954A1 (en)

Families Citing this family (66)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9607788D0 (en) * 1996-04-15 1996-06-19 De La Rue Thomas & Co Ltd Document of value
DE19633724A1 (en) * 1996-08-21 1998-02-26 Baasel Scheel Lasergraphics Gm Copy-protected security printing
GB9810399D0 (en) * 1998-05-14 1998-07-15 Rue De Int Ltd Holographic security device
GB2348852B (en) * 1999-03-03 2003-03-12 David Gifford Burder Ink printed diffractive optical elements
US6987590B2 (en) * 2003-09-18 2006-01-17 Jds Uniphase Corporation Patterned reflective optical structures
US7667895B2 (en) * 1999-07-08 2010-02-23 Jds Uniphase Corporation Patterned structures with optically variable effects
US6761959B1 (en) 1999-07-08 2004-07-13 Flex Products, Inc. Diffractive surfaces with color shifting backgrounds
US7047883B2 (en) 2002-07-15 2006-05-23 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US20070195392A1 (en) * 1999-07-08 2007-08-23 Jds Uniphase Corporation Adhesive Chromagram And Method Of Forming Thereof
DE19938829A1 (en) * 1999-08-19 2001-02-22 Orga Kartensysteme Gmbh Process for applying visually readable information to card-shaped data carriers
WO2001053113A1 (en) * 2000-01-21 2001-07-26 Flex Products, Inc. Optically variable security devices
US11768321B2 (en) 2000-01-21 2023-09-26 Viavi Solutions Inc. Optically variable security devices
FI116086B (en) * 2000-06-08 2005-09-15 Avantone Oy Check-marked paper or cardboard product and check-marked packaging
US20100085642A1 (en) * 2000-07-18 2010-04-08 Optaglio Limited Diffractive device
US20040032659A1 (en) * 2000-07-18 2004-02-19 Drinkwater John K Difractive device
DE10127981C1 (en) * 2001-06-08 2003-01-16 Ovd Kinegram Ag Zug Diffractive security element
GB0117391D0 (en) * 2001-07-17 2001-09-05 Optaglio Ltd Optical device and method of manufacture
US6692830B2 (en) * 2001-07-31 2004-02-17 Flex Products, Inc. Diffractive pigment flakes and compositions
US7625632B2 (en) * 2002-07-15 2009-12-01 Jds Uniphase Corporation Alignable diffractive pigment flakes and method and apparatus for alignment and images formed therefrom
US6841238B2 (en) 2002-04-05 2005-01-11 Flex Products, Inc. Chromatic diffractive pigments and foils
CA2470094C (en) 2001-12-18 2007-12-04 Digimarc Id Systems, Llc Multiple image security features for identification documents and methods of making same
CA2471457C (en) 2001-12-24 2011-08-02 Digimarc Id Systems, Llc Covert variable information on id documents and methods of making same
EP1467834A4 (en) 2001-12-24 2005-04-06 Digimarc Id Systems Llc Laser etched security features for identification documents and methods of making same
CA2470600C (en) 2001-12-24 2009-12-22 Digimarc Id Systems, Llc Systems, compositions, and methods for full color laser engraving of id documents
US7694887B2 (en) 2001-12-24 2010-04-13 L-1 Secure Credentialing, Inc. Optically variable personalized indicia for identification documents
US7221512B2 (en) * 2002-01-24 2007-05-22 Nanoventions, Inc. Light control material for displaying color information, and images
WO2003088144A2 (en) 2002-04-09 2003-10-23 Digimarc Id Systems, Llc Image processing techniques for printing identification cards and documents
US7824029B2 (en) 2002-05-10 2010-11-02 L-1 Secure Credentialing, Inc. Identification card printer-assembler for over the counter card issuing
US20100208351A1 (en) * 2002-07-15 2010-08-19 Nofi Michael R Selective and oriented assembly of platelet materials and functional additives
US11230127B2 (en) 2002-07-15 2022-01-25 Viavi Solutions Inc. Method and apparatus for orienting magnetic flakes
US7934451B2 (en) 2002-07-15 2011-05-03 Jds Uniphase Corporation Apparatus for orienting magnetic flakes
US7645510B2 (en) * 2002-09-13 2010-01-12 Jds Uniphase Corporation Provision of frames or borders around opaque flakes for covert security applications
US8025952B2 (en) 2002-09-13 2011-09-27 Jds Uniphase Corporation Printed magnetic ink overt security image
US9164575B2 (en) * 2002-09-13 2015-10-20 Jds Uniphase Corporation Provision of frames or borders around pigment flakes for covert security applications
US7674501B2 (en) * 2002-09-13 2010-03-09 Jds Uniphase Corporation Two-step method of coating an article for security printing by application of electric or magnetic field
US9458324B2 (en) 2002-09-13 2016-10-04 Viava Solutions Inc. Flakes with undulate borders and method of forming thereof
DE10252645A1 (en) * 2002-11-11 2004-05-27 Bühler AG Pigment for use e.g. in holography or document authentication has a diffractive structure with a spatial periodicity of at least a multiple of the longest wavelength of UV light
US7804982B2 (en) 2002-11-26 2010-09-28 L-1 Secure Credentialing, Inc. Systems and methods for managing and detecting fraud in image databases used with identification documents
DE602004030434D1 (en) 2003-04-16 2011-01-20 L 1 Secure Credentialing Inc THREE-DIMENSIONAL DATA STORAGE
KR101110767B1 (en) * 2003-07-14 2012-02-24 플렉스 프로덕츠, 인코포레이티드 Security products with overt and/or covert patterned layers and the method for producing the same
US7550197B2 (en) * 2003-08-14 2009-06-23 Jds Uniphase Corporation Non-toxic flakes for authentication of pharmaceutical articles
US7744002B2 (en) 2004-03-11 2010-06-29 L-1 Secure Credentialing, Inc. Tamper evident adhesive and identification document including same
EP1771758A2 (en) * 2004-07-26 2007-04-11 Applied Opsec, Inc. Diffraction-based optical grating structure and method of creating the same
US7367759B2 (en) * 2004-12-07 2008-05-06 A.M. Precision Machining, Inc. Surface relief grating image machining process and product
US7383999B2 (en) 2004-12-28 2008-06-10 Digimarc Corporation ID document structure with pattern coating providing variable security features
CA2541568C (en) 2005-04-06 2014-05-13 Jds Uniphase Corporation Dynamic appearance-changing optical devices (dacod) printed in a shaped magnetic field including printable fresnel structures
US20080274354A1 (en) * 2005-04-26 2008-11-06 Rettker James P Embossed Metallic Flakes Process and Product
AU2006202315B2 (en) * 2005-06-17 2011-01-27 Viavi Solutions Inc. Covert security coating
CA2564764C (en) * 2005-10-25 2014-05-13 Jds Uniphase Corporation Patterned optical structures with enhanced security feature
AU2006249295A1 (en) 2005-12-15 2007-07-05 Jds Uniphase Corporation Security device with metameric features using diffractive pigment flakes
GB0605360D0 (en) * 2006-03-16 2006-04-26 Dupont Teijin Films Us Ltd Method of manufacture
JP2007334076A (en) * 2006-06-16 2007-12-27 Dainippon Printing Co Ltd Optical diffraction structure
GB0613306D0 (en) * 2006-07-04 2006-08-16 Rue De Int Ltd Security device
CA2592667C (en) * 2006-07-12 2014-05-13 Jds Uniphase Corporation Stamping a coating of cured field aligned special effect flakes and image formed thereby
TWI301901B (en) * 2006-08-11 2008-10-11 Ind Tech Res Inst Identification device
JP4961944B2 (en) * 2006-10-24 2012-06-27 凸版印刷株式会社 Display and printed matter
TW200903465A (en) * 2007-07-03 2009-01-16 Ind Tech Res Inst Difrraction grating recording medium
WO2009010377A2 (en) * 2007-07-13 2009-01-22 Basf Se Process for preparing platelet-like (embossed) particles
KR20100110847A (en) * 2007-12-28 2010-10-13 롤링 옵틱스 에이비 Method of producing a microstructured product
JP2009193069A (en) 2008-02-13 2009-08-27 Jds Uniphase Corp Medium for laser printing including optical special effect flake
GB0817865D0 (en) * 2008-10-01 2008-11-05 Optaglio Sro Embedded element and related method
GB2464496B (en) * 2008-10-16 2013-10-09 Rue De Int Ltd Improvements in printed security features
MX340221B (en) 2012-01-12 2016-07-01 Viavi Solutions Inc Article with curved patterns formed of aligned pigment flakes.
US20140103634A1 (en) * 2012-10-15 2014-04-17 Opsec Security Group, Inc. Structured color filter device
CN103895374B (en) * 2013-11-01 2016-09-14 中钞油墨有限公司 There is anti-counterfeiting pattern of light structure changes and preparation method thereof
DE102017008918A1 (en) 2017-09-22 2019-03-28 Giesecke+Devrient Currency Technology Gmbh Platelet-shaped pigment, printing ink, security element and manufacturing process

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1957683A (en) * 1982-10-04 1984-04-12 Ovd Kinegram Ag Document with diffraction grating
AU6645186A (en) * 1985-12-23 1987-06-25 Flex Products, Inc. Optical thin film flakes, replicated optical coatings and coatings and inks incorporating same and method
AU6282890A (en) * 1989-09-04 1991-04-08 Commonwealth Scientific And Industrial Research Organisation Diffraction grating and method of manufacture
US5032003A (en) * 1988-12-12 1991-07-16 Landis & Gyr Betriebs Ag Optially variable surface pattern
AU3739093A (en) * 1992-03-12 1993-10-05 Commonwealth Scientific And Industrial Research Organisation Security diffraction grating with special optical effects

Family Cites Families (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3463118A (en) * 1967-04-10 1969-08-26 Remsen V Wood Diffraction grating instrument dials
US3580657A (en) * 1968-05-14 1971-05-25 Xerox Corp Blazed surface hologram
US3567561A (en) * 1969-01-09 1971-03-02 Remsen V Wood Diffraction type mosaic system
CH505394A (en) * 1970-08-05 1971-03-31 Balzers Patent Beteilig Ag Filters for lenses for generating optical images with diffraction phenomena
US4155627A (en) * 1976-02-02 1979-05-22 Rca Corporation Color diffractive subtractive filter master recording comprising a plurality of superposed two-level relief patterns on the surface of a substrate
US4589686A (en) * 1980-11-05 1986-05-20 Mcgrew Stephen P Anticounterfeiting method and device
US4402571A (en) * 1981-02-17 1983-09-06 Polaroid Corporation Method for producing a surface relief pattern
US4417784A (en) * 1981-02-19 1983-11-29 Rca Corporation Multiple image encoding using surface relief structures as authenticating device for sheet-material authenticated item
US4484797A (en) * 1981-07-20 1984-11-27 Rca Corporation Diffractive subtractive color filter responsive to angle of incidence of polychromatic illuminating light
AU550459B2 (en) * 1982-04-15 1986-03-20 Rca Corp. Authentication device
US4576439A (en) * 1982-09-15 1986-03-18 Rca Corporation Reflective diffractive authenticating device
US4547002A (en) * 1983-11-10 1985-10-15 U.S. Banknote Corporation Credit and identification cards having pieces of diffraction grating therein
DE3442794A1 (en) * 1983-11-24 1985-08-01 Karl 8058 Erding Rubenberger Process for producing forgery-proof symbols with holographically coded information
US4737448A (en) * 1986-03-31 1988-04-12 Xerox Corporation Color images formed by multiple diffraction gratings
US4788116A (en) * 1986-03-31 1988-11-29 Xerox Corporation Full color images using multiple diffraction gratings and masking techniques
US4832445A (en) * 1986-05-16 1989-05-23 American Bank Note Holographics, Inc. Security diffraction devices difficult to exactly duplicate
US5145212A (en) * 1988-02-12 1992-09-08 American Banknote Holographics, Inc. Non-continuous holograms, methods of making them and articles incorporating them
US5128779A (en) * 1988-02-12 1992-07-07 American Banknote Holographics, Inc. Non-continuous holograms, methods of making them and articles incorporating them
GB8807820D0 (en) * 1988-03-31 1988-05-05 Pizzanelli D J Light modifying & light filtering optical security device
CA2006056C (en) * 1988-12-19 1998-07-28 Robert Arthur Lee Diffraction grating
WO1991003747A1 (en) * 1989-09-04 1991-03-21 Commonwealth Scientific And Industrial Research Organisation Diffraction grating and method of manufacture
US5142383A (en) * 1990-01-25 1992-08-25 American Banknote Holographics, Inc. Holograms with discontinuous metallization including alpha-numeric shapes
US5291317A (en) * 1990-07-12 1994-03-01 Applied Holographics Corporation Holographic diffraction grating patterns and methods for creating the same
FR2671032A1 (en) * 1990-12-28 1992-07-03 Hologram Ind INFALSIFIABLE DOCUMENT LAMINATED WITH HOLOGRAM AND METHOD FOR MANUFACTURING SUCH A DOCUMENT.
CA2060057C (en) * 1991-01-29 1997-12-16 Susumu Takahashi Display having diffraction grating pattern
AU671588B2 (en) * 1991-06-05 1996-09-05 Mikoh Pty. Ltd. Optical memories incorporating diffraction gratings
WO1993018419A1 (en) * 1992-03-12 1993-09-16 Commonwealth Scientific And Industrial Research Organisation Security diffraction grating with special optical effects
US5296949A (en) * 1992-04-23 1994-03-22 Flexcon Company Inc. Optical authentication device
GB9211123D0 (en) * 1992-05-26 1992-07-08 Amblehurst Ltd Holographic device
WO1995002200A1 (en) * 1993-07-09 1995-01-19 Commonwealth Scientific And Industrial Research Organisation Multiple image diffractive device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1957683A (en) * 1982-10-04 1984-04-12 Ovd Kinegram Ag Document with diffraction grating
AU6645186A (en) * 1985-12-23 1987-06-25 Flex Products, Inc. Optical thin film flakes, replicated optical coatings and coatings and inks incorporating same and method
US5032003A (en) * 1988-12-12 1991-07-16 Landis & Gyr Betriebs Ag Optially variable surface pattern
AU6282890A (en) * 1989-09-04 1991-04-08 Commonwealth Scientific And Industrial Research Organisation Diffraction grating and method of manufacture
AU3739093A (en) * 1992-03-12 1993-10-05 Commonwealth Scientific And Industrial Research Organisation Security diffraction grating with special optical effects

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0730753A4 *

Also Published As

Publication number Publication date
CA2173838A1 (en) 1995-06-01
EP0730753A1 (en) 1996-09-11
JPH09506442A (en) 1997-06-24
EP0730753A4 (en) 1997-02-26
US5912767A (en) 1999-06-15
TW265421B (en) 1995-12-11

Similar Documents

Publication Publication Date Title
US5912767A (en) Diffractive indicia for a surface
TWI419799B (en) Security device formed by printing with special effect inks
TWI279422B (en) Alignable diffractive pigment flakes
US9983335B2 (en) Film element
US8100436B2 (en) Data support with an optically variable structure
RU2250500C2 (en) Ornament element
JP4701105B2 (en) Engraved optical variable image device
EP0194042A2 (en) Embossed articles
US20040022967A1 (en) Multi-layered body, in particular a multi-layered film and method for increasing the forgery protection of a multi-layered body
US20060263539A1 (en) Alignable Diffractive Pigment Flakes And Method And Apparatus For Alignment And Images Formed Therefrom
EA003711B1 (en) Safety element and a valuable object
KR102242089B1 (en) Articles with angled reflective segments
CA2417795A1 (en) Optically active structure for personalizing cards and the like, and method for the production thereof
US10780729B2 (en) Information recording medium and individual certificate medium
US20230234389A1 (en) Display
JP2001063300A (en) Method for preventing forgery of ovd forming medium, and ovd forming medium ensured of forgery prevention
AU674805B2 (en) Diffractive indicia for a surface
AU2018307307B2 (en) Optical structure and authentication body
WO2022260047A1 (en) 3d display, authenticator, and formation method
US20230018648A1 (en) Embossed film assembly having pastel holographic security features
JP7326727B2 (en) Display media and methods for creating display media
JP2004177540A (en) Method for preventing forgery of ovd medium, ovd medium subjected to forgery prevention and sticker using ovd medium
CA3213998A1 (en) Embossed film assembly having pastel holographic security features
JP2004255625A (en) Reversible recording medium and its manufacturing method

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AM AT AU BB BG BR BY CA CH CN CZ DE DK EE ES FI GB GE HU JP KE KG KP KR KZ LK LR LT LU LV MD MG MN MW NL NO NZ PL PT RO RU SD SE SI SK TJ TT UA US UZ VN

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): KE MW SD SZ AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 2173838

Country of ref document: CA

WWE Wipo information: entry into national phase

Ref document number: 08624536

Country of ref document: US

WWE Wipo information: entry into national phase

Ref document number: 1995901280

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1995901280

Country of ref document: EP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWW Wipo information: withdrawn in national office

Ref document number: 1995901280

Country of ref document: EP