CA2376463A1 - Security article including diffractive optic filter - Google Patents

Security article including diffractive optic filter Download PDF

Info

Publication number
CA2376463A1
CA2376463A1 CA002376463A CA2376463A CA2376463A1 CA 2376463 A1 CA2376463 A1 CA 2376463A1 CA 002376463 A CA002376463 A CA 002376463A CA 2376463 A CA2376463 A CA 2376463A CA 2376463 A1 CA2376463 A1 CA 2376463A1
Authority
CA
Canada
Prior art keywords
zone
security
security article
diffractive
optic filter
Prior art date
Legal status (The legal status 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 status listed.)
Abandoned
Application number
CA002376463A
Other languages
French (fr)
Inventor
Paul Zientek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Securency Pty Ltd
Original Assignee
Securency Pty Ltd.
Paul Zientek
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 Securency Pty Ltd., Paul Zientek filed Critical Securency Pty Ltd.
Publication of CA2376463A1 publication Critical patent/CA2376463A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/40Manufacture
    • B42D25/405Marking
    • B42D25/41Marking using electromagnetic radiation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/20Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
    • B42D25/29Securities; Bank notes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30Identification or security features, e.g. for preventing forgery
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/20Filters
    • G02B5/203Filters having holographic or diffractive elements
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; 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
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30Identification or security features, e.g. for preventing forgery
    • B42D25/328Diffraction gratings; Holograms

Abstract

A security article such as banknotes, credit cards, passports, security passes, etc. comprising a transparent plastics substrate (2) bearing a diffractive optic filter (6) comprising at least a first zone (7) and second zone (8), with first and second diffractive structures or gratings formed in each zone. The first diffractive structure being operative to discriminatingly project a first selected colour at a first selected colour at a viewing angle by diffracting at least a first spectral component (e.g. red and green) of polychromatic light transmitted through said first zone by at least an angle .theta. from said viewing angle, said first colour forming at least part of a projected security image when said diffractive optic filter is viewed at said viewing angle.

Description

CA 02376463 2001-12-28 Received 31 July 2001 CORRECTED VERSION

SECURITY ARTICLE INCLUDING DIFFRACTIVE OPTIC FILTER
The present invention relates generally to devices for authenticating various items which are subject to counterfeiting, and in particular to authenticating devices of this type which act to diffract incident light. The invention is suitable for use with banknotes and other security documents such as credit cards, passports, security passes, etc., and it will be convenient to hereinafter describe the invention in relation to that exemplary application.
It is to be appreciated, however, that the invention is not limited to use in this application.
A wide variety of security devices or features for security documents, such as banknotes, travellers' cheques or the like have been proposed previously. Examples of such security devices and features include optically variable devices such as holograms and diffraction gratings, security threads or strips, micro-print, fine line or "filigree" patterns, moire inducing patterns and optically variable inks.
However, recently considerable advances have been made in photocopying and like machines for the colour reproduction of documents. The advances in such machines, and in the technology associated with like equipment enabling the reproduction of banknotes and other security documents, increasingly diminishes the effectiveness of known security devices.
Accordingly, there is a need to provide security devices or features for incorporation in security articles or documents of increasing sophistication in order to make unauthorised reproduction of such objects increasingly difficult.
A security article comprising a transparent substrate bearing a diffractive optic filter comprising:
at least a first zone and a second zone, and a first and second diffractive structure respectively formed in the first and second zones, AMENDED SNEE
IPEA/AU

CA 02376463 2001-12-28 Received 31 July 2001 CORRECTED VERSION
2 the first diffractive structure being operative to discriminatingly project a first selected colour at a viewing angle by diffracting at least a first spectral component of polychromatic light transmitted through the first zone by an 8 from the viewing angle, the second diffractive structure being operative to discriminatingly project a second selected colour at the viewing angle by diffracting at least a second spectral component of polychromatic light transmitted through the second zone by the angle A from the viewing angle, the first and second colours together form at least part of a projected security image when the security article is viewed from the viewing angle.
In one embodiment, the substrate is formed of transparent plastics material. The transparent plastic substrate may comprise at least one film of transparent polymeric material.
An opacifying layer may be applied to at least a first surface of a substrate, said opacifying layer only partly covering said first surface of the substrate to leave at least said diffractive optic filter essentially uncovered. The substrate may include an uncovered region at least partially surrounding said diffractive optic filter.
The security article may be a security document, such as a banknote.
The following description refers in more detail to the various features of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the security article is illustrated in a preferred embodiment. It is to be understood that the security article of the present invention is not, however, limited to that preferred embodiment.
In the drawings:
Figure 1 is a plan view of a banknote in accordance with one embodiment of the invention;
~~~r~r' CA 02376463 2001-12-28 Received 31 July 2001 CORRECTED VERSION
2a Figure 2 is a schematic diagram illustrating the operation of the diffractive optic filter of the banknote of Figure 1 in the presence of incident polychromatic light; and Figure 3 is a schematic diagram illustrating the projection of a security image by the diffractive optic filter of the banknote of Figure 1.
Referring now to Figure 1, there is shown generally a banknote 1, being one example of a security article according to the present invention. The banknote 1 has a substantially planar structure and comprises a flexible sheet-like substrate 2 of transparent plastics material. The substrate 2 is covered over most of its upper and
3 lower surfaces by opacifying layers 3 and 4. As shown in Figure 1, the opacifying layers are not applied over the entire surfaces of the sheet-like substrate 2, and thus leave a transparent portion 5 of the substrate which is at least partially uncovered by the opacifying layers 3 and 4. This transparent, essentially uncovered portion constitutes a "window" in the banknote through which light may be transmitted.
The substrate 2 of transparent plastics material is preferably formed from a transparent polymeric material which may be made from at least one biaxially oriented film. The substrate may comprise a single layer film of polymeric material. Alternatively, the substrate may comprise a laminate of two or more layers of transparent biaxially oriented polymeric film.
The opacifying layers 3 and 4 may comprise in one or more of a variety of opacifying inks which can be used in the printing of banknotes or security documents. For example, the layers of opacifying ink may comprise pigmented coatings comprising a pigment, such as titanium dioxide dispersed within a binder or carrier of heat activated cross-linkable polymeric material. Alternatively, a substrate of transparent plastics material 2 may be sandwiched between opacifying layers of paper to which indicia is printed or otherwise applied.
Whilst the banknote in Figure 1 is shown as having opacifying layers applied to both upper and lower surfaces, in other embodiments of the invention, only one of the surfaces of the banknote may have an opacifying layer applied thereto.
According to the present invention, the transparent substrate 2 bears a diffractive optic filter 6. The diffractive optic filter may be incorporated into the surface of the substrate 2, or may be formed within a transfer foil structure that is later applied to the substrate 2. The diffractive optic filter comprises a first zone 7, and, in this example, at least a second zone 8. A diffractive structure is formed in each of the first and second zones 7 and 8. More specifically, each region incorporates a transmissive diffractive structure, such as a diffraction grating, formed as a microscopic 3-D relief pattern. The grating structures of both the first diffractive structure formed in the first zone 7 and the second diffractive structure formed in the second zone 8 have profiles and line spacings, or a periodicity, chosen so as to diffract at least a first spectral component of polychromatic light transmitted
4 through the transmissive diffractive structure by a given angle B. The characteristics of each of the diffractive structures in the two zones 7 and 8 are chosen so that different spectral components of the polychromatic light transmitted by each through the window in the banknote 1 are diffracted, so that the remaining undiffracted spectral component projected by each of the diffractive structures produces visually discernible colours which together form a projected security image.
The characteristics of each of the diffractive structures in the first and second zones 7 and 8, such as the line spacing, profile and depth of the grating structure, may be chosen to precisely define that spectral component of the polychromatic light which is to be diffracted.
Whilst the embodiment of the security article shown in Figure 1 includes a diffractive optic filter having two zones, each of which includes a different diffractive structure, in other embodiments of the invention only one such zone having a single diffractive structure may be used. Similarly, three or more zones, each having a separate diffractive structure, may be incorporated in other embodiments.
Figures 2 and 3 shown one example in which the authenticity of the banknote 1 may be verified by a user. As seen in Figure 2, a user may place the banknote 1 directly in front of an appropriate polychromatic light source. For example, the banknote 1, containing the diffractive optic filter in the clear window 5 thereof, may be placed against a video display terminal (VDT) screen 10. The VDT screen contains an array of red, green and blue (RGB) pixels, which respectively transmit a red, green and blue spectral component of the polychromatic light emitted from the screen.
In other embodiments, a different polychromatic light source may be used, such as a broad flat white light source such as a fluorescent light box.
Preferably the light source used will cover an area which is larger than the area of the diffractive optic filter, and will produce light that can be separated into at least two spectral components.

The banknote 1 itself may also act as the polychromatic light source. For example, the banknote 1 may be folded so that a multi-coloured surface is superposed with the clear window 5. Ambient light may then be reflected from the multi-coloured surface of the banknote 1 and transmitted through the diffractive
5 optic filter 6 in the clear window 5.
In the configuration shown in Figure 2, the light emanating from the light source 10 passes outwards towards a user 11 situated at a viewing angle from the banknote l, in this case perpendicular to the plane of the banknote.
In this example, the first diffractive structure formed in the first zone 7 of the diffractive optic filter 5 acts to diffract the red and green spectral components of the polychromatic light transmitted through the substrate 2 of the banknote 1, and then through the first zone 7. The characteristics of the first diffractive structure are chosen such that the red and green spectral components are diverted by at least an angle 8 similarly, the second diffractive structure formed in the second zone 8 of the diffractive optic filter 6 acts to diffract the green and blue spectral components of the polychromatic light emitted from the VDT screen 10 by at least the angle 8.
Accordingly, only the blue spectral component of the light emitted from the VDT screen is transmitted to the user 11 through the first zone 7, whilst only the red spectral component of the polychromatic from the VDT screen 10 is transmitted by the second zone 8 to the user 11.
The colours transmitted by each of the zones of the diffractive optic filter 6 may be chosen so that each transmits a colour which is visually discernible from the colours in each of the other zones. In this way, the colours from the various zones of the diffractive optic filter combine to form at least part of a projected security (schematically represented in Figures 1, 2 and 3 in the form of an "S").
As may be best appreciated from Figure 3, the angle 8 by which the different spectral components of polychromatic light are diffracted by each of the first and second diffractive structures, should be chosen so that the diffracted spectral components are diverted outside of the users field of view 12.
Referring again to Figure 1, an uncovered zone 13 may be left around at least part of the diffractive optic filter 6 in the window 5, this uncovered portion
6 allowing all spectral components of the polychromatic light emitted from VDT
screen 10 to be transmitted to the user 11. This enables the user 11 to more easily distinguish between the unfiltered light transmitted through the uncovered portion 13 and that transmitted through the diffractive optic filter 6.
Many other variations may be made to the above described embodiment without departing from the spirit or ambit of the invention.

Claims (6)

1. A security article comprising a transparent substrate bearing a diffractive optic filter comprising:
at least a first zone and a second zone, and a first and second diffractive structure respectively formed in the first and second zones, the first diffractive structure being operative to discriminatingly project a first selected colour at a viewing angle by diffracting at least a first spectral component of polychromatic light transmitted through the first zone by an angle .theta. from the viewing angle, the second diffractive structure being operative to discriminatingly project a second selected colour at the viewing angle by diffracting at least a second spectral component of polychromatic light transmitted through the second zone by the angle .theta. from the viewing angle, the first and second colours together form at least part of a projected security image when the security article is viewed from the viewing angle.
2. A security article according to claim 1, wherein the substrate is formed of transparent plastics material.
3. A security article according to claim 2, wherein the transparent plastic substrate comprises at least one film of transparent polymeric material.
4. A security article according to any one of the preceding claims, and further comprising an opacifying layer applied to at least a first surface of a substrate, said opacifying layer only partly covering said first surface of the substrate to leave at least said diffractive optic filter essentially uncovered.
5. A security article according to claim 4, wherein the substrate includes an uncovered region at least partially surrounding said diffractive optic filter.
6. A security article according to any one of the preceding claims, wherein said security article is a security document, such as a banknote.
CA002376463A 1999-06-30 2000-06-26 Security article including diffractive optic filter Abandoned CA2376463A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AUPQ1288A AUPQ128899A0 (en) 1999-06-30 1999-06-30 Security article including diffractive optic filter
AUPQ1288 1999-06-30
PCT/AU2000/000723 WO2001002192A1 (en) 1999-06-30 2000-06-26 Security article including diffractive optic filter

Publications (1)

Publication Number Publication Date
CA2376463A1 true CA2376463A1 (en) 2001-01-11

Family

ID=3815477

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002376463A Abandoned CA2376463A1 (en) 1999-06-30 2000-06-26 Security article including diffractive optic filter

Country Status (9)

Country Link
EP (1) EP1240031A1 (en)
JP (1) JP2003503759A (en)
KR (1) KR20020022729A (en)
CN (1) CN1359340A (en)
AU (1) AUPQ128899A0 (en)
CA (1) CA2376463A1 (en)
NZ (1) NZ516254A (en)
TW (1) TW567146B (en)
WO (1) WO2001002192A1 (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7052762B2 (en) 2001-05-24 2006-05-30 3M Innovative Properties Company Low Tg multilayer optical films
DE10254500B4 (en) * 2002-11-22 2006-03-16 Ovd Kinegram Ag Optically variable element and its use
US7820282B2 (en) 2003-04-10 2010-10-26 3M Innovative Properties Company Foam security substrate
US7655296B2 (en) 2003-04-10 2010-02-02 3M Innovative Properties Company Ink-receptive foam article
DE102004003984A1 (en) * 2004-01-26 2005-08-11 Giesecke & Devrient Gmbh Lattice image with one or more grid fields
GB2441261B (en) * 2005-06-17 2009-05-27 Securency Pty Ltd Security documents incorporating colour shifting inks
AU2006257720B2 (en) * 2005-06-17 2010-12-02 Securency International Pty Ltd Security documents incorporating colour shifting inks
GB0613306D0 (en) 2006-07-04 2006-08-16 Rue De Int Ltd Security device
DE202010008331U1 (en) 2010-08-23 2011-11-29 Tremco Illbruck Produktion Gmbh Foam sealing tape
CN102542313B (en) * 2012-01-05 2015-04-15 苏州大学 Double-channel grating structure, identification structure and card identification method
DE102012010908A1 (en) * 2012-06-01 2013-12-05 Giesecke & Devrient Gmbh Verification of value documents with a window with diffractive structures
DE102012108169A1 (en) 2012-09-03 2014-05-28 Ovd Kinegram Ag Security element as well as security document
WO2015173364A1 (en) * 2014-05-16 2015-11-19 U-Nica Technology Ag Data carrier comprising a customizable authenticity feature
CN107633596A (en) * 2017-08-14 2018-01-26 深圳怡化电脑股份有限公司 A kind of method, apparatus and storage medium for identifying bank card

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2125337B (en) * 1981-08-24 1985-05-01 Commw Scient Ind Res Org Improved banknotes and the like
US5876068A (en) * 1988-03-04 1999-03-02 Gao Gessellschaft Fur Automation Und Organisation Gmbh Security element in the form of a thread or strip to be embedded in security documents and methods of producing it
DE4343387A1 (en) * 1993-12-18 1995-06-29 Kurz Leonhard Fa Visually identifiable, optical security element for documents of value
GB2296784A (en) * 1995-01-07 1996-07-10 Debden Security Printing Ltd A method of forming a composite image & a lamina for use in the method
AUPO384796A0 (en) * 1996-11-26 1996-12-19 Commonwealth Scientific And Industrial Research Organisation Colour image diffractive device

Also Published As

Publication number Publication date
CN1359340A (en) 2002-07-17
NZ516254A (en) 2002-05-31
JP2003503759A (en) 2003-01-28
WO2001002192A1 (en) 2001-01-11
KR20020022729A (en) 2002-03-27
EP1240031A1 (en) 2002-09-18
AUPQ128899A0 (en) 1999-07-22
TW567146B (en) 2003-12-21

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Legal Events

Date Code Title Description
FZDE Discontinued