WO1990006539A1 - Security marking - Google Patents

Security marking Download PDF

Info

Publication number
WO1990006539A1
WO1990006539A1 PCT/GB1989/001443 GB8901443W WO9006539A1 WO 1990006539 A1 WO1990006539 A1 WO 1990006539A1 GB 8901443 W GB8901443 W GB 8901443W WO 9006539 A1 WO9006539 A1 WO 9006539A1
Authority
WO
WIPO (PCT)
Prior art keywords
saturable absorber
security mark
wavelength
photochromic compound
absorber comprises
Prior art date
Application number
PCT/GB1989/001443
Other languages
French (fr)
Inventor
Stephen Charles Wallace
Original Assignee
Traqson Limited
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 Traqson Limited filed Critical Traqson Limited
Publication of WO1990006539A1 publication Critical patent/WO1990006539A1/en

Links

Classifications

    • 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
    • B41M3/144—Security printing using fluorescent, luminescent or iridescent effects
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/40—Manufacture
    • B42D25/405—Marking
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K9/00—Tenebrescent materials, i.e. materials for which the range of wavelengths for energy absorption is changed as a result of excitation by some form of energy
    • C09K9/02—Organic tenebrescent materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
    • B42D25/378—Special inks
    • B42D25/387—Special inks absorbing or reflecting ultraviolet light

Definitions

  • This invention relates to security marking and in particular to the use of marking substances which include a photochromic compound.
  • marking substances which include a photochromic compound.
  • These substances can be arranged to take a colourless form when applied to an article requiring authentication, for example a personal identification document.
  • the photochromic compound can be converted to a coloured form by irradiation with UV, the optically detectable colour change in the marking substance then serving to authenticate the document.
  • Security marking substances as outlined above are known and reference is directed by way of example to WO 88/06306; JP 62227794 and WO 88/01288.
  • the present invention consists in one aspect in a method of marking an item with a security mark which exhibits a reversible and optically detectable change on exposure to light of a specific wavelength, comprising the steps of applying to the article a marking substance comprising a photochromic compound convertible from one photochrome to another on exposure to light of said wavelength, said compound being covered by a controlled absorption layer containing a saturable absorber at said wavelength, whereby there is defined a threshold intensity of light at said wavelength beneath which threshold there is by reason of absorption in said controlled absorption layer no detectable change in the mark within a given time period, a detectable change occuring substantially immediately at intensities above said threshold.
  • the present invention consists in a security mark comprising a body of marking substance comprising a photochromic compound and a sunlight protection layer covering said marking substance, the sunlight protection layer comprising a saturable absorber.
  • saturable absorber compounds have the property that below a threshold light intensity, an equilibrium is established between molecular processes of photon absorption and relaxation, such that the transmissivity at the specific wavelength of operation is very low. Above the threshold intensity, the photon absorption process is saturated, with all absorber molecules being held in the higher energy state. Above this threshold intensity, therefore, the substance has significant transmissivity at the specific wavelength.
  • Saturable absorbers are known for use as high speed switches in lasers and reference is directed in this regard to "Lasers - Light amplifiers and oscillators" - Dieter Ross - 199 Academic Press.
  • the transmissivity of the layer to UV at normal sunlight intensities is very low but that at a UV intensity achievable - with careful design - in authentication apparatus, the transmissivity is high.
  • Figure 1 is a diagramatic section through a security mark in accordance with this invention.
  • FIG. 2 is a diagramatic section through an alternative security mark according to this invention.
  • a marking substance 10 is applied to a substrate 12 by printing or any other suitable application technique.
  • the marking substance includes a photochromic compound which is preferably a fulgide but which could take other forms such as a spiropyran.
  • the detailed structure of the photochromic compound forms no part of the present invention and it will suffice to make reference to the known art, examples of which are GB-A-1464 603, GB-A-2002752 and GB-A-2051813.
  • the photochromic compound is incorporated in the marking substance by any of a variety of appropriate techniques.
  • the photochromic compound may be dissolved or dispersed in a solution of polymeric material which is cast, coated or otherwise applied to the substrate.
  • a photochromic fulgide can be dissolved in a solution of cellulose acetate in acetone with a film of the marking _ n _
  • polyesters e.g. polyethylene terephthalate; acrylates, e.g. PMMA; olefin polymers or co-polymers; vinyl polymers, e.g. PVA or PVC; polycarbonates and polyamides.
  • Alternative organic solvents are toluene and chlorinated hydrocarbons.
  • the marking substance 10 comprises a 2.3% concentration of the photochromic fulgide Aberchrome 5 ⁇ 0 (available from Aberchromics Limited, Victoria) in PMMA cast from a solution in ethyl acetate.
  • the formed security mark has an area of 1 sq cm and the thickness of the marking substance is 5 microns.
  • a controlled absorption layer 14 This comprises a 10 concentration of a saturable absorber in an appropriate matrix such as polyvinyl alcohol.
  • the saturable absorber molecule is triazinyl stilbene.
  • the thickness of the controlled absorption layer is 5 microns and it is calculated that at normal sunlight intensities of UV, the controlled absorption layer will decrease the flux of UV incident upon the marking substance by
  • the security mark is irradiated with high intensity UV so as to convert the photochromic compound to a coloured form. This changing colour may be observed visually.
  • the intensity of UV employed in the activation step is in excess of the threshold at which the saturable absorber is saturated. Thus at an intensity of 15 kw suitably focussed, the controlled absorption layer has a transmissivity of approximately 80%.
  • the high intensity UV may be provided, for example, by a flashlamp with appropriate focusing, or other high intensity pulsed light sources.
  • the use of a saturable absorber in the manner according to this invention has the advantage that the lifetime of the security mark on exposure to sunlight is substantially increased.
  • the controlled absorption layer has little effect upon visible - for example, green or red - light so that the photochromic compound can be returned rapidly to its colourless form by irradiation at the appropriate wavelength. This can be done by exposure to sunlight or another white light source. Since the transmissivity of the controlled absorption layer is relatively high above the threshold intensity, the time taken to colour the security mark in the activation step is not substantially increased.
  • saturable absorbers can be employed and these can be provided in a controlled absorption layer in a variety of techniques.
  • One example of an alternative saturable absorber molecule useful with fulgide photochromies is 1,4-Bis (o-methylstyryl) benzene. This can be formed as a screen ink using a hydrocarbon solvent.
  • the wavelength band of 3 O to 390"TM is appropriate for a wide range of photochromic fulgides.
  • the marking substance need not be a polymeric film; it may take the form of, for example, a paint or ink containing a photochromic compound or may in appropriate cases consist of a photochromic compound alone.

Abstract

A security mark has a photochromic compound covered by a controlled absorption layer comprising a saturable absorber. Light of a wavelength serving to convert the photochromic compound is at low intensity absorbed by the saturable absorber. A photochromic compound converted by UV can thus be sunlight protected. At high intensities, the absorption of the saturable absorber drops to permit conversion of the photochromic compound.

Description

SECURITY MARKING
This invention relates to security marking and in particular to the use of marking substances which include a photochromic compound. These substances can be arranged to take a colourless form when applied to an article requiring authentication, for example a personal identification document. The photochromic compound can be converted to a coloured form by irradiation with UV, the optically detectable colour change in the marking substance then serving to authenticate the document.
Security marking substances as outlined above are known and reference is directed by way of example to WO 88/06306; JP 62227794 and WO 88/01288.
It is known that exposure to UV over a period of time can destroy the photochromic effect in certain compounds. The life of a particular marking substance will depend upon the flux of UV to which it is subjected whether during the authentication procedure or extraneously. The UV applied during the authentication step is liable to be a critical factor in determining the life of a marking substance only in the case of items requiring very frequent authentication. Extraneous UV from sunlight will be an important factor in many cases where no control can be exercised over the manner in which the marked item is stored.
It is one object of this invention to provide a method of marking offering increased lifetimes.
In applications where a relatively high degree of security is required, it would be advantageous to provide a more demanding authentication step, preferably without significantly increasing the complexity of the authentication apparatus. It is thus a further object of the present invention to provide an improved method of marking offering closer control over the essential requirements of the authentication step. Accordingly, the present invention consists in one aspect in a method of marking an item with a security mark which exhibits a reversible and optically detectable change on exposure to light of a specific wavelength, comprising the steps of applying to the article a marking substance comprising a photochromic compound convertible from one photochrome to another on exposure to light of said wavelength, said compound being covered by a controlled absorption layer containing a saturable absorber at said wavelength, whereby there is defined a threshold intensity of light at said wavelength beneath which threshold there is by reason of absorption in said controlled absorption layer no detectable change in the mark within a given time period, a detectable change occuring substantially immediately at intensities above said threshold.
Preferably, the saturable absorber comprises a laser dye having at said wavelength, an absorbtion cross section in the excited state which small compared with the absorbtion cross section in the ground state.
In another respect, the present invention consists in a security mark comprising a body of marking substance comprising a photochromic compound and a sunlight protection layer covering said marking substance, the sunlight protection layer comprising a saturable absorber.
It should be recognised that the term "light" as used herein is not to be regarded as restricted to visible light.
A variety of saturable absorber compounds-are known. They have the property that below a threshold light intensity, an equilibrium is established between molecular processes of photon absorption and relaxation, such that the transmissivity at the specific wavelength of operation is very low. Above the threshold intensity, the photon absorption process is saturated, with all absorber molecules being held in the higher energy state. Above this threshold intensity, therefore, the substance has significant transmissivity at the specific wavelength. Saturable absorbers are known for use as high speed switches in lasers and reference is directed in this regard to "Lasers - Light amplifiers and oscillators" - Dieter Ross - 199 Academic Press.
In the practice of the present invention, it can be arranged, by appropriate selection of a saturable absorber and the concentration and thickness of the controlled absorption layer, that the transmissivity of the layer to UV at normal sunlight intensities is very low but that at a UV intensity achievable - with careful design - in authentication apparatus, the transmissivity is high.
The invention will now be described by way of example with reference to the accompanying drawings in which:-
Figure 1 is a diagramatic section through a security mark in accordance with this invention, and
Figure 2 is a diagramatic section through an alternative security mark according to this invention.
Referring to Figure 1, a marking substance 10 is applied to a substrate 12 by printing or any other suitable application technique. The marking substance includes a photochromic compound which is preferably a fulgide but which could take other forms such as a spiropyran. The detailed structure of the photochromic compound forms no part of the present invention and it will suffice to make reference to the known art, examples of which are GB-A-1464 603, GB-A-2002752 and GB-A-2051813.
The photochromic compound is incorporated in the marking substance by any of a variety of appropriate techniques. For example, the photochromic compound may be dissolved or dispersed in a solution of polymeric material which is cast, coated or otherwise applied to the substrate. For example, a photochromic fulgide can be dissolved in a solution of cellulose acetate in acetone with a film of the marking _ n _
substance being formed upon evaporation of acetone. Alternative polymers are polyesters e.g. polyethylene terephthalate; acrylates, e.g. PMMA; olefin polymers or co-polymers; vinyl polymers, e.g. PVA or PVC; polycarbonates and polyamides. Alternative organic solvents are toluene and chlorinated hydrocarbons.
In the illustrated example, the marking substance 10 comprises a 2.3% concentration of the photochromic fulgide Aberchrome 5^0 (available from Aberchromics Limited, Cardiff) in PMMA cast from a solution in ethyl acetate. The formed security mark has an area of 1 sq cm and the thickness of the marking substance is 5 microns.
There is provided over the marking substance 10 a controlled absorption layer 14. This comprises a 10 concentration of a saturable absorber in an appropriate matrix such as polyvinyl alcohol. In this example the saturable absorber molecule is triazinyl stilbene. For detailed information concerning the proproperties of this known saturable absorber, reference is directed to textbooks such as "Laser Dyes - Properties of organic compounds for dye lasers" - Mitsuo Maeda 1987 Academic Press, especially Table 20. The thickness of the controlled absorption layer is 5 microns and it is calculated that at normal sunlight intensities of UV, the controlled absorption layer will decrease the flux of UV incident upon the marking substance by
2 factor of 10 .
In the authentication step, the security mark is irradiated with high intensity UV so as to convert the photochromic compound to a coloured form. This changing colour may be observed visually. The intensity of UV employed in the activation step is in excess of the threshold at which the saturable absorber is saturated. Thus at an intensity of 15 kw suitably focussed, the controlled absorption layer has a transmissivity of approximately 80%. The high intensity UV may be provided, for example, by a flashlamp with appropriate focusing, or other high intensity pulsed light sources. The use of a saturable absorber in the manner according to this invention has the advantage that the lifetime of the security mark on exposure to sunlight is substantially increased. However, the controlled absorption layer has little effect upon visible - for example, green or red - light so that the photochromic compound can be returned rapidly to its colourless form by irradiation at the appropriate wavelength. This can be done by exposure to sunlight or another white light source. Since the transmissivity of the controlled absorption layer is relatively high above the threshold intensity, the time taken to colour the security mark in the activation step is not substantially increased.
In a modification, illustrated in Figure 2, a base coat 16 is interposed between the marking substance 10 and the substrate 12. This base coat may typically comprise a one to two micron layer of polyvinyl chloride which serves to enhance optical contrast and to protect the photochromic compound from possibly damaging effects of the substrate. The use of such a base coat would, for example, be important in the case of paper or other fibre based substrates having relatively high moisture levels and containing fillers and other reactants having a possibly deleterious effect upon the photochromic compound.
It should be understood that this invention has been described by way of example only and a variety of modifications are possible without departing from the scope of the invention.
Other saturable absorbers can be employed and these can be provided in a controlled absorption layer in a variety of techniques. One example of an alternative saturable absorber molecule useful with fulgide photochromies is 1,4-Bis (o-methylstyryl) benzene. This can be formed as a screen ink using a hydrocarbon solvent. The wavelength band of 3 O to 390"™ is appropriate for a wide range of photochromic fulgides. Beyond the specific saturable absorbers mentioned, it will be possible to employ a range of laser dyes • absorbing in the wavelength range of interest and having an absorption cross section in the excited state which is small compared to that in the ground state*and thus being capable of saturation. Reference is directed in this regard to Maeda ibid and to "Handbook of fluorescent spectra of aromatic molecules" Isador Berl an - 171 Academic Press.
It is not necessary for the entire security mark to be covered by a single, contiguous controlled absorption layer; separate blocks of the marking substance may be covered by respective controlled absorption layers. The marking substance need not be a polymeric film; it may take the form of, for example, a paint or ink containing a photochromic compound or may in appropriate cases consist of a photochromic compound alone.

Claims

1. A method of marking an item with a security mark which exhibits a reversible and optically detectable change on exposure to light of a specific wavelength, comprising the steps of applying to the article a marking substance comprising a photochromic compound convertible from one photochrome to another on exposure to light of said wavelength, said compound being covered by a controlled absorption layer containing a saturable absorber at said wavelength, whereby there is defined a threshold intensity of light at said wavelength beneath which threshold there is by reason of absorption in said controlled absorption layer no detectable change in the mark within a given time period, a detectable change occuring substantially immediately at intensities above said threshold.
2. A method according to Claim 1, wherein the saturable absorber comprises a laser dye having at said wavelength an absorbtion cross section in the excited state which is small compared with the absorbtion cross section in the ground state.
3. A method according to Claim 1, wherein the saturable absorber comprises triazinyl stilbene.
4. A method according to Claim 1, wherein the saturable absorber comprises 1,4-Bis(o-methylstyryl)benzene.
5. A method according to any one of the preceding claims, wherein the photochromic compound comprises a fulgide.
6. A security mark formed by the method of any one of the preceding claims.
7. A security mark comprising a body of marking substance comprising a photochromic compound and a sunlight protection layer covering said marking substance, the sunlight protection layer comprising a UV saturable absorber.
8. A security mark according to Claim 7. wherein the saturable absorber comprises a laser dye having a UV absorbtion cross section in the excited state which is small compared with the absorbtion cross section in the ground state.
9. A security mark according to Claim 7, wherein the saturable absorber comprises triazinyl stilbene.
10. A security mark according to Claim 7, wherein the saturable absorber comprises 1, -Bis(o-methylstyryl)benzene.
PCT/GB1989/001443 1988-12-01 1989-12-01 Security marking WO1990006539A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB888828091A GB8828091D0 (en) 1988-12-01 1988-12-01 Security marking
GB8828091.2 1988-12-01

Publications (1)

Publication Number Publication Date
WO1990006539A1 true WO1990006539A1 (en) 1990-06-14

Family

ID=10647806

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1989/001443 WO1990006539A1 (en) 1988-12-01 1989-12-01 Security marking

Country Status (6)

Country Link
AU (1) AU4744790A (en)
CA (1) CA2004423A1 (en)
GB (1) GB8828091D0 (en)
IL (1) IL92524A0 (en)
WO (1) WO1990006539A1 (en)
ZA (1) ZA899183B (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5289547A (en) * 1991-12-06 1994-02-22 Ppg Industries, Inc. Authenticating method
US5330686A (en) * 1992-08-19 1994-07-19 Ppg Industries, Inc. Temperature stable and sunlight protected photochromic articles
AU651876B2 (en) * 1991-04-17 1994-08-04 J.S. Mcmillan Printing Group A printing process
EP0980763A1 (en) * 1998-08-14 2000-02-23 BUNDESDRUCKEREI GmbH Security document with light-active dyes for authenticity verification
EP1038690A1 (en) * 1999-03-22 2000-09-27 Fabriques De Tabac Reunies S.A. Printed latent raster image
WO2003002351A1 (en) * 1999-12-21 2003-01-09 Mib - Munich Innovative Biomaterials Gmbh Non-falsifiable information carrier material, information carrier produced therefrom and test device therefor
US6552290B1 (en) 1999-02-08 2003-04-22 Spectra Systems Corporation Optically-based methods and apparatus for performing sorting coding and authentication using a gain medium that provides a narrowband emission
EP1786976A1 (en) * 2004-09-10 2007-05-23 Stora Enso Oyj Method of marking a material, marked material and verification of genuineness of a product
WO2009013528A1 (en) * 2007-07-24 2009-01-29 Innovia Films Limited Indicia means
FR2927840A1 (en) * 2008-02-25 2009-08-28 Oberthur Technologies Sa "DOCUMENT COMPRISING A SECURITY MARK WITH VARIABLE VISUAL PERCEPTION"
US8088848B2 (en) 2007-07-24 2012-01-03 Innovia Films Limited UV barrier film
US9079374B2 (en) 2007-05-04 2015-07-14 Innovia Films Limited Sealable, peelable film
WO2015184172A1 (en) * 2014-05-30 2015-12-03 Cabela's Incorporated System and method for application of chromic compositions
US9822229B2 (en) 2007-05-24 2017-11-21 Innovia Films Limited Low emissivity film

Citations (6)

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Publication number Priority date Publication date Assignee Title
US2927025A (en) * 1956-10-23 1960-03-01 Ibm Photosensitive materials and recording media
EP0070631A1 (en) * 1981-07-16 1983-01-26 Ecc International Limited Stabilisation of photochromic compounds, and the use of stabilised photochromic compounds
EP0195898A1 (en) * 1985-01-31 1986-10-01 American Optical Corporation A method of increasing the light fatigue resistance of a photochromic composition and photochromic composition
EP0241247A2 (en) * 1986-04-07 1987-10-14 RAYCHEM CORPORATION (a Delaware corporation) Reversible temperature indicating compositions
EP0248907A1 (en) * 1985-11-06 1987-12-16 Research Development Corporation of Japan Photochromic material, photochromic element and method of recording and erasing data
WO1988006306A1 (en) * 1987-02-13 1988-08-25 Courtaulds Plc Marking

Patent Citations (6)

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Publication number Priority date Publication date Assignee Title
US2927025A (en) * 1956-10-23 1960-03-01 Ibm Photosensitive materials and recording media
EP0070631A1 (en) * 1981-07-16 1983-01-26 Ecc International Limited Stabilisation of photochromic compounds, and the use of stabilised photochromic compounds
EP0195898A1 (en) * 1985-01-31 1986-10-01 American Optical Corporation A method of increasing the light fatigue resistance of a photochromic composition and photochromic composition
EP0248907A1 (en) * 1985-11-06 1987-12-16 Research Development Corporation of Japan Photochromic material, photochromic element and method of recording and erasing data
EP0241247A2 (en) * 1986-04-07 1987-10-14 RAYCHEM CORPORATION (a Delaware corporation) Reversible temperature indicating compositions
WO1988006306A1 (en) * 1987-02-13 1988-08-25 Courtaulds Plc Marking

Non-Patent Citations (1)

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Title
Patent Abstracts of Japan, Vol 7, No 254, M255, abstract of JP 58-138687, MITSUBISHI SEISHI K.K. publ 1983-08-17 *

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU651876B2 (en) * 1991-04-17 1994-08-04 J.S. Mcmillan Printing Group A printing process
US5289547A (en) * 1991-12-06 1994-02-22 Ppg Industries, Inc. Authenticating method
US5330686A (en) * 1992-08-19 1994-07-19 Ppg Industries, Inc. Temperature stable and sunlight protected photochromic articles
EP0980763A1 (en) * 1998-08-14 2000-02-23 BUNDESDRUCKEREI GmbH Security document with light-active dyes for authenticity verification
US6234537B1 (en) 1998-08-14 2001-05-22 Bundesdruckerei Gmbh Security document with optically excitable dyes for authenticity check
US6552290B1 (en) 1999-02-08 2003-04-22 Spectra Systems Corporation Optically-based methods and apparatus for performing sorting coding and authentication using a gain medium that provides a narrowband emission
US6832783B2 (en) 1999-02-08 2004-12-21 Spectra Science Corporation Optically-based methods and apparatus for performing sorting, coding and authentication using a gain medium that provides a narrowband emission
EP1038690A1 (en) * 1999-03-22 2000-09-27 Fabriques De Tabac Reunies S.A. Printed latent raster image
WO2000056553A1 (en) * 1999-03-22 2000-09-28 Philip Morris Products S.A. Latent halftone image
WO2003002351A1 (en) * 1999-12-21 2003-01-09 Mib - Munich Innovative Biomaterials Gmbh Non-falsifiable information carrier material, information carrier produced therefrom and test device therefor
EP1786976A1 (en) * 2004-09-10 2007-05-23 Stora Enso Oyj Method of marking a material, marked material and verification of genuineness of a product
EP1786976A4 (en) * 2004-09-10 2010-06-16 Stora Enso Oyj Method of marking a material, marked material and verification of genuineness of a product
US7897212B2 (en) 2004-09-10 2011-03-01 Stora Enso Oyj Method of marking material, marked and verification of genuineness of a product
US9079374B2 (en) 2007-05-04 2015-07-14 Innovia Films Limited Sealable, peelable film
US11254096B2 (en) 2007-05-04 2022-02-22 Innovia Films Limited Sealable, peelable film
US9822229B2 (en) 2007-05-24 2017-11-21 Innovia Films Limited Low emissivity film
WO2009013528A1 (en) * 2007-07-24 2009-01-29 Innovia Films Limited Indicia means
US8088848B2 (en) 2007-07-24 2012-01-03 Innovia Films Limited UV barrier film
US8664307B2 (en) 2007-07-24 2014-03-04 Innovia Films Limited UV barrier film
US8906987B2 (en) 2007-07-24 2014-12-09 Innovia Films Limited UV barrier film
FR2927840A1 (en) * 2008-02-25 2009-08-28 Oberthur Technologies Sa "DOCUMENT COMPRISING A SECURITY MARK WITH VARIABLE VISUAL PERCEPTION"
WO2009112723A3 (en) * 2008-02-25 2009-10-29 Oberthur Technologies Document including a variably visually perceptible safety mark
WO2015184172A1 (en) * 2014-05-30 2015-12-03 Cabela's Incorporated System and method for application of chromic compositions

Also Published As

Publication number Publication date
AU4744790A (en) 1990-06-26
IL92524A0 (en) 1990-08-31
ZA899183B (en) 1991-09-25
CA2004423A1 (en) 1990-06-01
GB8828091D0 (en) 1989-01-05

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