GB2379409A

GB2379409A - Micro-particle coded security tag

Info

Publication number: GB2379409A
Application number: GB0106640A
Authority: GB
Inventors: John Anthony Yandell
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-03-16
Filing date: 2001-03-16
Publication date: 2003-03-12
Anticipated expiration: 2021-03-16
Also published as: GB0106640D0; GB2379409B

Abstract

A security tag has coded indicia on its surface to enable tags to be uniquely identified. Tags are typically of the order of 50 micrometres in size and are substantially invisible to the naked eye. The markings 10,11,12 may take the form of, for example, a triangle, a square or a circle. Null markers 14 and an orientation marking 6 may also be included. The tag surface shape may also represent an identification code. The tag may have an inbuilt transmitter 26, powered by a battery 20 and/or solar cell 22. The transmitter may be activated by an external stimulus such as a change in ambient temperature or pressure. Tags may be dispersed in a carrier agent such as paint, glaze or ink. They may be included in a spoiling agent such as smoke as part of a method to identify stolen goods. The spoiling agent may be discharged into a protected area containing, for example, bank notes, upon activation of a delivery system.

Description

SECURITY TAG The present invention relates to a security tag and associated security devices incorporating such a security tag. The tag can be deployed by a delivery system during an attempted theft.

The use of smoke, dyes and inks to degrade or stain money during a robbery is a commonly known deterrent. However, the spoiling agents commonly used do not allow the stained money, or indeed an individual stained by the spoiling agent, to be linked to a particular robbery or incident because the spoiling agent employed in an incident cannot be distinguished from those employed in other incidents. This limits the forensic value of recovered stained material because it cannot be used as evidence by the police of the commission of a particular crime. Furthermore, neither can recovered stained items, and in particular money, be easily returned to their rightful owner because it is not possible to distinguish similar items that have been stained in separate incidents.

One solution to this problem is the use of a variety of rare base elements as additives to the spoiling agents. By adding varying quantities of each individual base element to the spoiling agent a unique spectral signature can be generated for each spoiling agent.

However, such additives are very expensive and can only be used in liquid systems.

Additionally, these additives also have the disadvantage of having a relatively short storage life of approximately two years.

The deterrent value of spoiled or stained money is greatly increased if such stained money can be removed from general circulation. However, bank notes that have been stained in such a manner during a robbery are not presently easily detected by the bank note processing machines currently used within the banking system, and in particular by the high speed counting machines. There is therefore a need for an improved means of detecting such stained notes to facilitate easy removal of them from the banking system.

Identification of valuable objects by the application of the serial numbers printed onto small dots of material that are dispensed within a glue is also a well used strategy to deter

robbery. An example of one such system is the'Alpha Dot'system produced by Alpha Scientific Limited and described in EP 760991B. The size of each dot is generally about 1 or 2mm, this size making it easy for the police to read the serial number using a hand-held magnifying glass but equally has the disadvantage that the dots are relatively easy for a criminal to see and remove. It would therefore be beneficial to provide a similar marking system wherein the individual markers were of a much reduced size so that they were not visible to the human eye.

According to a first aspect of the present invention there is provided a security tag having a physical structure providing a means of identifying the tag, wherein the security tag is difficult to locate with the naked eye by virtue of its small size, and wherein the tag has a plurality of markings on the surface of the tag, the markings being selected from a plurality of shapes.

Advantageously, each individual marking may have one of two states. The states may correspond to set and not set, such that the markers can form a binary type code. The markings may be formed as depressions in the surface of the security tag or a portion protruding from the surface. Each state corresponds to a predetermined value whereby the plurality of individual markings comprises an identification code. Since each individual marking may be one of a plurality of different shapes, coding can be performed by the presence or absence of a marker, and the shape of the marker.

Preferably the security tag has one of a plurality of predetermined shapes, each shape representing an identification code. Each shape may be a relatively simple geometric shape, such as a regular polygon.

Additionally, each security tag may have at least one manufactured irregularity formed thereon. The manufactured irregularity may be a recess formed in perimeter of a shape or a projection formed in the perimeter of the shape.

The unique physical structure of the security tag may be viewed with an optical microscope.

Additionally or alternatively, the security tag may comprise a transmitter, the transmitter transmitting a signal indicating the presence of the security tag. The signal may also include an identification code.

Preferably, the transmitter is associated with a power source. The power source may be arranged to be activated in response to an externally applied stimulus. The externally applied stimulus may be either a change of ambient pressure, a change of ambient temperature, an electrical signal or an applied magnetic field. Alternatively, the transmitter may be arranged to be inductively coupled to an external power supply.

Preferably the transmitted signal may be either an electromagnetic signal or an optical signal.

According to a further embodiment of the present invention there is provided a spoiling agent for use in a spoiling agent delivery system, the spoiling agent comprising a carrier agent including a plurality of security tags, which tags are difficult to locate with or substantially invisible to the naked eye by virtue of their small size.

In further embodiments of the present invention the security tags may be included within a carrier agent that is suitable for direct application onto an object to be marked by such tags.

The carrier agent may be an adhesive, paint, pottery glaze or ink.

According to a third aspect of the present invention there is provided a method of identifying stolen goods, comprising the steps of : providing a spoiling agent comprising a plurality of markers, said markers being members of a batch such that markers within said batch carry a shared identification whilst markers from a first batch are distinguishable from other batches and sufficiently small that they are difficult to locate with the naked eye; and

providing a delivery system, such that if an attempt is made to steal goods from a protected region, the delivery system is actuated to deliver the markers to the goods such that at least a proportion of the markers attach to the goods.

Preferably a trusted authority maintains a record of when a theft occurred and which batch of markers were released to mark the stolen goods. Thus once goods, such as bank notes are recovered, they can be identified and/or associated with a specific theft.

According to a further aspect of the present invention there is provided a security tag comprising a machine detectable device, and wherein the security tag is difficult to locate with or substantially invisible to the naked eye due to its small size.

Preferably the security tag includes a transmitter which transmits an identifying signal. The transmitter may only become active when in the presence of a"wake up"signal. Such a signal may be issued by an automated note counting machine or by a handheld unit.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure I shows a first embodiment of the present invention with a square surface on which an identification code is marked; Figure 2 shows a further alternative embodiment of the security tag in which the shape of the surface having the identification code thereon is a pentagon ; Figure 3 shows an embodiment of the present invention having a transmitter located thereon; and Figure 4 shows a delivery system according to a further embodiment of the invention.

Figure I shows a plan view of a surface of a security tag 1 according to an embodiment of the present invention. The shape of the surface shown is a square. As illustrated later,

other shapes may be provided such that individual security tags may be distinguished by virtue of their different shapes. The surface of the tag 1 has a number of individual markings 10, 11, 12,14 formed on it. Each marking 10, 11, 12,14 may either be made by forming a depression 4 in the surface of the security tag or by forming a raised portion 2 protruding from the surface of the security tag or a region where a marking would be expected but is not formed. In this way it is possible to arrange for each marking to have one of two states. Arranged on a further part of the surface 1 there is an orientation marking 6 comprising an enlarged impression formed in the surface. The orientation marking 6 is located on the surface of the security tag at such a location in that it provides a reference point for reading the individual markings in the correct order in order to establish an identification code represented by the markings. In the example shown in Figure 1 the identification code is intended to be read in a row by row fashion left to right when the orientation marking is located in the upper left-hand corner of the surface.

In the example shown in Figure 1 the individual markings may either be a triangle 10 a square 11, a circle 12 or a null marker (in this case represented by outline square 14). In this case the base of the identification code is base 4, with a triangle 10 representing the digit 1, square 11 representing a 2, and circle 12 representing the digit 3, and in the null marker representing zero the identification code illustrated in Figure 1 corresponds to the base 4 number 123032103210. The absence of a marking, or only a faintly or partially formed marking may represent a zero.

Also shown in Figure 1 are two further identifying marks 16 that may be provided to further individualise the structure of the security tag. The further markings 16 shown in Figure 1 are grooves formed in the peripheral edge of the security tag. Although two grooves are shown in Figure 2 on adjacent sides of the square surface, any number of grooves may be provided at various locations around the periphery of the surface in order to further distinguish one security tag from another. Equally, instead of using grooves formed in the periphery of the surface, projections may be formed serving the same purpose as the groove. It will be appreciated that the or each further marking 16 may also be used on security tags that do not have individual markings formed on the surface of the tag, in which case it is only the combination of the shape of the cross-sectional surface of

the security tag and the location and number of the additional markings that distinguishes one security tag from another.

As already mentioned, the shape of the surface of the security tag may be any one of a number of different shapes. It is preferred, although not necessary, that each shape be a regular polygon. There is shown in Figure 2 a security tag having the shape of a regular pentagon. In addition to the differently shaped surface, the security tag in Figure 2 also includes individual markings 10,11, 12,14 in a similar manner to the security tag in Figure 1, and also includes an orientation marking 6. In the example shown in Figure 2 the identification code reads 333222111000.

It is calculated that by using a combination of the identification marks on the surface of the security tag and around the peripheral edges, together with differently shaped cross-sectional surfaces, it is possible to generate approximately 1,600 million differently structured security tags.

The unique structure of the security tags, and indeed the actual security tags themselves, are invisible or substantially invisible to the human eye due to their particularly small size. In preferred embodiments each security tag has a maximum dimension of between 2 and 60 microns, although a favoured range of dimension is between 40 and 60 microns. Although particles of this size may be easily inhaled it has been found that particles in this particular range do not pose a significant health risk. The particles are produced at this very small scale using conventional lithographic masking and etching techniques, as are well known in the semiconducter industry. Thus many thousands of individual tags, each bearing the same identity can be formed on a wafer by masking and etching. Grooves can be etched around each tag, such that the tags can be separated from each other in a final etching step.

Although substantially invisible to the naked human eye, the unique structure of the security tag together with any identification code formed thereon is easily examined using conventional laboratory microscopes, such as an optical microscope.

Figure 3 shows an alternative embodiment of the security tag of the present invention. Figure 3 shows the general components of a security tag having an inbuilt transmitter. In the embodiment shown, the tag comprises a battery, such as a thick film battery 20, a solar cell 22, an active transmitter circuit 26 and a passive communication circuit 28. Also included in the security tag is control circuitry 24. All of the elements of the security tag shown in Figure 3 are manufactured using known integrated circuit techniques. The various components shown in Figure 3 may be provided either in addition to the physical structure previously described in relation to Figures 1 or 2, or may be provided as an alternative arrangement.

The security tag shown in Figure 3 is arranged to transmit an identification signal using the active transmitter 26 when activated by an external stimulus. The power necessary for such transmission is supplied by the battery 20 in addition to, or as an alternative to power provided by the solar cell 22. The external stimulus provided to activate the transmitter 22 may be an electrical signal or may be a change in one or more of the ambient physical parameters experienced by the security tag. For example, a transmitter may be activated in response to a change in the ambient pressure or temperature. Such a change in pressure or temperature may be detected by a sensor 30 included in the security tag. A control circuit 24 is provided to control the operation of the sensor 30 and transmitter 26. The transmitter 26 may transmit a predefined encoded signal, the encoded signal being unique to each particular security tag, or may simply transmit a signal indicative of the presence of the security tag.

In an alternative arrangement (not shown) the security tag of Figure 3 may be provided without a battery 20 or solar cell 22, in which case the power for the transmitter 26 must be supplied from an external source. For example, the transmitter 26 may be inductively coupled to an externally applied alternating magnetic field. In this case the externally applied alternating magnetic field may be generated by a detection probe used to detect the presence of the security tag on an object.

The security tags according to any of the previously described embodiments may be used to protect a variety of valuable objects in a variety of methods. A batch of security tags all

with the same unique structure may be included within a spoiling agent within a conventionally known spoiling agent delivery system such as a cash-in-transit delivery system, such that if the spoiling agent is caused to be applied to the bank notes being carried, the bank notes are also covered in a number of security tags. Because the security tags have a unique identifying structure, recovered bank notes may be linked to a particular incident. Equally, any unauthorised person causing the spoiling agent to be activated is also likely to have a number of the security tags adhered to themselves such that any security tag recovered from individual by conventional forensic techniques can be used to link the individual with a particular incident.

An example of such a delivery system is shown in Figure 4, in combination with a security container 40. The delivery system includes a spoiling agent reservoir 46, the spoiling agent including a single batch of security tags, connected to an actuator 48. The actuator is connected to the reservoir by a conduit 50 and to a delivery pipe 52. In the event of the delivery system being actuated, the actuator 48 causes the spoiling agent held in the reservoir 46 to be pumped through the delivery pipe 52 and into a protected area 44 via outlet nozzles 54. Consequently any valuables held in the protected area, such as bank notes 42 in Figure 5, are marked by the spoiling agent and have a number of security tags attached.

Equally, bank notes that have been marked by a spoiling agent including security tags according to the embodiment described with reference to Figure 3, but in such a manner that they have not been removed from circulation, may be easily identified by applying an activation signal in the vicinity of the bank notes in order to activate the transmitter 26, thus easily signalling their presence.

Because of the small size of the security tags they may be included in a variety of carrier agents allowing them to be applied to a variety of objects to be protected. For example the security tags may be included in ink based spoiling agents, or smoke based spoiling agents as described above, or may be included in an ink used for a marker pen, or in an adhesive. The security tags may also be included within paint such that individual works of art may

be protected, or used in pottery glaze such that valuable items of pottery or sculpture may equally be protected.

Claims

CLAIMS 1. A security tag having a physical structure providing a means of identifying the tag, wherein said security tag is difficult to locate with the naked eye by virtue of its small size, and the tag has a plurality of markings on a surface of the tag, the markings being selected from a predefined plurality of shapes.
2. A security tag according to claim 1, wherein each marking has one of two states.
3. A security tag according to claim 2, wherein the states may correspond to set and not set.
4. A security tag according to claim 2 or 3, wherein each of the states is formed from one of a depression in the surface of the security tag, a portion protruding from said surface and the absence of one of said markings.
5. A security tag according to claim 2,3, or 4, wherein each state corresponds to a predetermined value whereby said plurality of individual markings comprise an identification code.
6. A security tag according to any preceding claim, wherein said security tag has one of a plurality of predetermined shapes, each shape representing an identification code.
7. A security tag according to claim 6, wherein said shape is a regular polygon.
8. A security tag according to claim 6 or 7, wherein said identification code further comprises at least one manufactured irregularity in said shape.
9. A security tag according to claim 8, wherein said manufactured irregularity is a recess formed in the perimeter of the shape.

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10. A security tag according to claim 9, wherein said manufactured irregularity is a projection formed on the perimeter of the shape.
11. A security tag according to any preceding claim wherein said physical structure is visible when viewed with an optical microscope.
12. A security tag according to any preceding claim wherein said tag further comprises a transmitter.
13. A security tag according to claim 12, wherein said transmitter transmits a signal indicating a presence of the security tag.
14. A security tag according to claim 13, wherein said signal includes an identification code.
15. A security tag according to claim 13,14, or 15, wherein said transmitter is associated with a power source.
16. A security tag according to claim 15, wherein said power source is arranged to be activated in response to an externally applied stimulus.
17. A security tag according to claim 16, wherein said externally applied stimulus may be one from a change of ambient pressure, a change of ambient temperature, an electrical signal and an applied magnetic field.
18. A security tag according to claim 12,13 or 14, wherein said transmitter is arranged to be inductively coupled to an external power supply.
19. A security tag according to any one of claims 13 to 18, wherein said signal may be one from an electromagnetic signal and an optical signal.

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20. A security tag according to any preceding claim, wherein said security tag has a dimension of between 2 and 60 microns.
21. A security tag according to claim 20, wherein said security tag has a dimension of between 40 and 60 microns.
22. A spoiling agent for use in a spoiling agent delivery system said spoiling agent comprising a carrier agent including a plurality of security tags according to any preceding claim.
23. A carrier agent containing a plurality of security tags as claimed in any one of claims 1 to 21, wherein said carrier agent is suitable for application onto an object to be marked by said tags.
24. A carrier agent according to claim 23, wherein said carrier agent is one from an adhesive, paint, pottery glaze and ink.
25. A method of identifying stolen goods, comprising the steps of : providing a spoiling agent comprising a plurality of markers, said markers being members of a batch wherein markers within said batch carry a shared identification whilst markers from a first batch are distinguishable from other batches and wherein the markers are sufficiently small that they are difficult to locate with the naked eye; and providing a marker delivery system, such that if an attempt is made to steal goods from a protected region, the marker delivery system is actuated to deliver the markers to the goods such that at least a proportion of the markers attach to the goods.

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26. A method according to claim 25, wherein a trusted authority maintains a record of when a theft occurred and which batch of markers were released to mark the stolen goods, whereby recovered stolen goods can be identified and associated with a specific theft, recorded by said trusted authority.
27. A security tag substantially as described and/or as shown in the accompanying figures.