WO2001084519A2

WO2001084519A2 - Hand-held scanner deactivator to deactivate magnetomechanical eas markers

Info

Publication number: WO2001084519A2
Application number: PCT/US2001/014389
Authority: WO
Inventors: Richard Copeland; Ron Easter
Original assignee: Sensormatic Electronics Corp
Current assignee: Sensormatic Electronics Corp
Priority date: 2000-05-04
Filing date: 2001-05-02
Publication date: 2001-11-08
Anticipated expiration: 2002-11-04
Also published as: WO2001084519A3; AU2001261176A1

Abstract

The invention concerns an extended range magnetic core deactivating system (system) for deactivating an electronic article surveillance (EAS) marker. The system includes a magnetic core deactivator having a picture frame geometry, adapted to be mounted on a hand-held scanner, capable of transmitting a degaussing waveform for deactivating the EAS marker.

Description

HAND-HELD SCANNER DEACTIVATOR TO DEACTIVATE MAGNETOMECHANICAL EAS MARKERS

CROSS REFERENCE TO RELATED APPLICATIONS (Not Applicable)

STATEMENT REGARDING FEDERALLY SPONSORED

RESEARCH OR DEVELOPMENT (Not Applicable)

FIELD OF THE INVENTION This invention relates to the field of electronic article surveillance (EAS) systems, and more particularly, to a method and system for deactivating EAS markers.

BACKGROUND OF THE INVENTION Electronic article surveillance systems are known in the art wherein surveillance is carried out by transmitting a magnetic field into a detection zone. In these systems, determining the presence of the articles under surveillance is accomplished by sensing perturbations to the transmitted field. Perturbations to the transmitted field are generated by electronically detectable markers attached to or incorporated into the articles. One type of electronically detectable and deactivatable marker is the magnetomechanical marker disclosed in U.S. Patent No. 4,510,489. Magnetomechanical markers include an active element and a bias element. When the bias element is magnetized, it applies a bias magnetic field to the active element. The bias magnetic field in turn causes the active element to be mechanically resonant at a predetermined frequency upon exposure to an interrogation signal which alternates at the predetermined frequency. By detecting magnetomechanical markers, EAS systems prevent the unauthorized removal of goods having a marker from establishments such as retail outlets. However, EAS systems must also be able to deactivate markers when the removal of a marked item is authorized. Such is the case when a customer has paid for a marked item within the retail store. In that case, the EAS system must deactivate the marker so that removal of the marked article does not trigger an alarm condition in the EAS system.

Magnetomechanical EAS markers may be deactivated by exposing the bias element to an alternating magnetic field of sufficient magnitude to degauss the bias element. After the bias element is degaussed, the marker's resonant frequency is substantially shifted from the predetermined frequency. Thus, the amplitude of the marker's response to the interrogation signal becomes too low for detection by the detecting apparatus. In practice, after the clerk identifies and prices an article, commonly done with a hand-held scanner device, the clerk must also perform the separate operation of deactivating the magnetomechanical EAS marker. Deactivation is usually accomplished by the clerk passing each marked article over a stationary deactivator located somewhere on or within the checkout counter. Thus, a clerk must perform two operations for each marked article involved in a given transaction. One operation to identify an item for pricing, and another operation to deactivate a magnetomechanical EAS marker. As a result, the time needed to complete a transaction is doubled, thereby decreasing efficiency. Moreover, such decreased efficiency may lead to customer dissatisfaction.

An example of a known stationary magnetomechanical EAS marker deactivator makes use of arrays of permanent magnets arranged so that the polarities of the magnets are arranged in alternating orientation along the array. When this magnetic field is applied to the bias element, the magnetic domain structure of the bias element is changed so that the bias element no longer provides the bias field required to place the active element in an activated state. This type of deactivator apparatus is often enclosed within a low-profile pad structure. Successful deactivation requires the clerk to apply the magnetomechanical EAS marker to the pad structure.

Several systems have been developed in an attempt to combine the pricing and deactivation steps into a single operation. Within such systems, the EAS marker is commonly incorporated into a label which can contain identifying information such as a bar code. One example of a deactivation device for magnetomechanical EAS markers, is the LS-4000 boot deactivator for use with the LS-4000 hand-held scanner manufactured by Symbol Technologies. Such deactivation devices incorporate multiple permanent magnet arrays in a "boot" or housing for placement on the end of a hand-held scanner. Thus, if a magnetomechanical EAS marker is housed within a product label and placed on an article for sale, the marker can be deactivated at or about the same time that the product bar code is read by the hand-held scanner. Unfortunately, such permanent magnet array solutions suffer from having a limited deactivation range. The deactivation range is the maximum distance an EAS marker can pass from the deactivation system and still be properly deactivated. Presently within the art, deactivation ranges for permanent magnet deactivation systems are within the range of 2 millimeters.

Yet another disadvantage of permanent magnet deactivators is that hand-held scanners operate most efficiently when positioned at distances greater than 2 millimeters from the label being scanned. Therefore, the clerk must still perform two operations. The clerk must first scan the article at a distance which enables proper scanning of the article by the hand-held scanner. Then the clerk must bring the article closer to the hand-held scanner for deactivation of the magnetomechanical EAS marker. Also known within the art, but differing from the invention disclosed herein, are deactivation systems as described in U.S. Patent No. 5,059,951 for use with radio frequency EAS markers of the variety described in U.S. Patent No. 4,498,076. The system utilizes antennas operating near the resonant frequency of the radio frequency marker, which contains a resonant marker circuit having at least one resonant frequency. The marker circuit is electronically deactivated by a breakdown mechanism operative within the resonant structure of the marker to cause vaporization of a conductive area or short-circuiting of capacitor plates to destroy the resonant properties of the circuit. A deactivator provides electromagnetic energy at a resonant frequency of the marker circuit of sufficient energy to cause electrical breakdown and deactivation of the marker circuit. Deactivation systems for magnetomechanical EAS markers built for use with data collection systems, such as hand-held scanners, suffer from the deficiency of having a limited reliable deactivation range. As a result, there has arisen a need for an improved deactivation system for deactivation of magnetomechanical EAS markers having an increased deactivation range.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an improved deactivation system for deactivation of magnetomechanical EAS markers (EAS markers).

It is a further object of the invention to increase the deactivation range of deactivation systems for use with hand-held scanners. Another object of the invention is to provide a deactivation system having unique magnetic core properties for improved quality levels of marker deactivation. It is yet another obj ect of the invention to provide a deactivation system which replaces the permanent magnet array with a magnetic core deactivator, thereby creating a significant increase in the deactivation range. Notably, the range of deactivation can be extended from about 2 mm to about 4 cm. Another benefit of the magnetic core deactivator disclosed herein is that the orientation of the hand-held scanner as it relates to the marker for deactivation is much less critical. This benefit is a result of the extended deactivation range of the invention and the geometry of the invention. An additional object of the invention is to provide a deactivation system for use with low energy bias EAS markers.

The invention concerns an extended range magnetic core deactivating system (system) for deactivating an EAS marker. The system includes a magnetic core deactivator having a picture frame geometry, adapted to be mounted on a hand-held scanner, capable of transmitting a degaussing waveform for deactivating the EAS marker.

According to one embodiment, the deactivator is specially adapted for use with a hand-held scanner which has an optical scanner integrated within a scanning end portion. The magnetic core deactivator is formed to fit around a perimeter of the scanning end to perform EAS deactivation without interfering with the operation of the optical scanner.

In one advantageous embodiment of the invention, the system can include first, second, third, and fourth core elements, each of the core elements can have at least one winding of wire and the first and second core elements have an orthogonal orientation relative to the third and fourth core elements. The first and second core elements can have the same magnetization orientation; and the third and fourth core elements can have the same magnetization orientation. Further, the first, second, third, and fourth core elements can be of substantially equal length and can have balanced excitation levels.

In another embodiment of the invention, the first and second core elements can be substantially equivalent in length; and the third and fourth core elements can be substantially equivalent in length. In this case, the first and second core elements can be longer than the third and fourth core elements. Similar to the previous embodiment, each of the first, second, third, and fourth core elements can have balanced excitation levels.

The system, responsive to the detection of an EAS marker, further can automatically emit the degaussing waveform. Alternatively, the system, responsive to the hand-held scanner reading a bar code, can automatically emit the degaussing waveform. In yet another alternative embodiment, the system, responsive to a manual triggering means, can automatically emit the degaussing waveform. Also, core elements one and two can be energized in an alternating fashion with the core elements three and four.

The invention also concerns a method for deactivating an EAS marker. The method can include receiving a signal from a triggering means. In response to the signal, the system automatically can energize a picture frame geometry magnetic core deactivator capable of transmitting a degaussing waveform for deactivating the EAS marker. The method further can include emitting the degaussing waveform from the picture frame geometry magnetic core deactivator.

In one advantageous embodiment, the signal is generated in response to the detection of the EAS marker. In another embodiment, the signal is generated in response to the reading of a bar code by the hand-held scanner. In yet another embodiment, the triggering means can be manually activated. Further, the automatic energizing step can include energizing core elements one and two in an alternating fashion with the core elements three and four.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS There are presently shown in the drawings embodiments which are presently preferred, it being understood, however, that the invention is not so limited to the precise arrangements and instrumentalities shown, wherein:

Fig. 1 is an exemplary illustration of the inventive system disclosed herein. Fig. 2 depicts exemplary drive circuitry. Fig. 3 is an exemplary illustration of the picture frame geometry of the magnetic core deactivator disclosed herein. Fig. 4 is a block diagram of the system of Fig. 1.

Fig. 5 is a flow chart illustrating the method disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION A hand-held scanner deactivator to deactivate EAS markers having an extended deactivation range according to the invention is disclosed herein. The invention can be employed to deactivate EAS markers attached to articles. Fig. 1 is an exemplary illustration of the inventive system. The system preferably includes drive circuitry 19, and boot 15 for attaching and operatively connecting the magnetic core deactivator 21 (not shown) to a handheld scanner 17. The hand-held scanner 17 is the variety commonly used at retail check-out counters for scanning product labels, and is well known in the art. An example of a hand-held scanner for use with the invention disclosed herein, can be an LS-4000 series scanner, such as the LS-4004, manufactured by Symbol Technologies. Other examples of hand-held scanners also include the Barcode Anything SCAN CCD manufactured by Zebra Technologies, and the Wireless IR CCD Scanner manufactured by Worthington Data Solutions.

Boot 15 houses the magnetic core deactivator 21, and serves as a means for securing the magnetic core deactivator to the hand-held scanner 17. The boot 15 can be secured as shown to the end of the hand-held scanner 17 by any suitable means. For example, a friction fitting or simple mechanical latching engagement can be used for this purpose. Front face 13 of boot 15 is preferably formed of a transparent material to allow unfettered operation of the hand-held scanner laser optics through the front face 13. Specifically, such a material would allow a laser scanner beam to pass through unaffected, thereby allowing the scanner gun to operate properly. Alternatively, the boot 15 can have no front face 13. In either case, article labels can be scanned through the boot 15 while it engages the hand-held scanner 17; and the invention is not so limited by the particular form of the boot 15. Boot 15 is preferably formed of magnetically transparent material so as to not interfere with the operation of the invention.

Drive circuitry 19 can be incorporated into the boot 15 and operatively connected to the magnetic core deactivator 21 through appropriate interface circuitry. Preferably, however, to minimize the size of boot 15, the drive circuitry is a separate unit operatively connected to the magnetic core deactivator 21. According to a preferred embodiment, magnetic core deactivator 21 is configured as shown in Fig. 3. The core is shown in plan view in Fig. 3 and is generally planar with a hollow or square or "picture frame" configuration formed by core elements 1, 2, 3, and 4. The core elements 1, 2, 3 and 4 are preferably formed from any of a variety of well known ferromagnetic materials which are commercially available. For example, powdered metal, cast iron silicon steel and carbon steel will are acceptable. Coils 5, 6, 1, and 8 are preferably formed of magnet wire wound about each of the core elements 1 , 2, 3, and 4 respectively. As shown in Fig. 3, the coils 5, 6 are preferably arranged so that their respective axes of winding are formed parallel to one another and perpendicular to the axes of coils 7 and 8. Each of the coils 5, 6, 7, and 8 has respective leads for connecting the coils to suitable drive circuitry. In Fig. 3, each of the coil 5, 6, 7, and 8 is shown as being rather sparsely wound. In a preferred embodiment, the coils may in fact consist of turns which may number in the hundreds.

Preferably, magnetic core elements 1 and 2 are arranged in a parallel fashion, as are magnetic core elements 3 and 4. Thus, magnetic core elements 1 and 3 are preferably perpendicular to magnetic core elements 3 and 4. It should be appreciated by those skilled in the art that the elements need not be exactly parallel, and that minor deviations within design tolerances are acceptable so long as the operation of the invention is not compromised.

According to a preferred embodiment, the drive circuitry 19 functions so that the coils 5, 6, 7 and 8 are selectively excited in a predetermined manner to achieve two distinct operating modes. In each mode, an AC driving signal is preferably applied to a respective parallel pair of coils 5, 6, or 7, 8 to generate an alternating magnetic deactivation field. The result is the alternate formation of mutually orthogonal magnetic dipoles. The phases of excitation of the coils is preferably such that no net flux circulates in the magnetic deactivation core 21. When coils 5 and 6 are driven in the first mode, a dipole is formed in a horizontal direction parallel to sides 1 and 2 of the core 21. Conversely, when the coils 7 and 8 are driven in the second mode, a dipole is formed in a horizontal direction parallel to the sides 3 and 4.

Hand-held scanner heads can differ in shape from model to model and among different manufacturers. For example, some hand-held scanner heads can be rectangular in shape, while others may be square in shape. Accordingly, it will be readily appreciated that minor deviations of length with regard to core elements 1, 2, 3, 4 not materially affecting the deactivation range can be acceptable. Thus, the resulting geometry of the magnetic core deactivator 21 can be square or rectangular in shape. Further, it should be appreciated by those skilled in the art that coils 5, 6, 7, 8 and the associated core elements 1, 2, 3, 4 preferably have balanced excitation levels or amp turns relative to one another. In the case of rectangular hand-held scanner heads, the core elements 1, 2, 3, 4 can be adjusted in length to achieve an appropriate fit. In this case, it should be appreciated by those skilled in the art that the excitation levels or amp-turns of the two sets of coils 5, 6, and 7, 8 can be adjusted so that the magnetic fields of the two vector orientations are balanced.

According to a preferred embodiment of the invention, the exciter signal used to drive coils 5, 6, 1, and 8 is an alternating voltage which produces a substantial alternating magnetic field when applied to the coils. In this regard, it will be recognized that the provision of the magnetic core elements 1, 2, 3, and 4 allows a much stronger deactivation field to be generated for a given level of the driving signal as compared to an arrangement which makes use of air cores. Conversely, the magnetic core elements permit a given level of deactivation field to be maintained at a given distance from the deactivation core 21 at a substantially lower power level of driving signal as compared to that which would be required if an air core was used.

According to a preferred embodiment, each time a deactivation cycle is triggered, a drive signal will be applied to each set of orthogonal coils during respective time windows. These time windows are preferably sufficiently delayed from one another so that the resultant magnetic fields of one set of parallel coils do not coincide in time so as to significantly effect the corresponding set of orthogonal coils. However, the drive signal applied to the respective orthogonal sets of coils preferably does occur sufficiently closely spaced in time so that any physical movement of the scanner 17 on which the deactivation core 21 is mounted is minimal relative to an EAS marker which is to be deactivated. Thus, the drive signal for one orthogonal set of coils is preferably delayed by a time which is approximately one millisecond to 100 milliseconds relative to the other drive signal, it being understood that the invention is not limited in this regard.

Fig. 2 is a schematic diagram showing one possible implementation of drive circuit which can be used for providing drive signals to one set coils 5, 6 or 7, 8 respectively. According to a preferred embodiment, the switch S2 is opened and switch S 1 is closed during a charging cycle. After capacitor Cl is charged to the predetermined DC voltage Vo, switch SI can be opened and capacitor Cl remains charged at Vθ- Upon receiving a deactivation control signal from interface and control circuit 23, drive circuitry 19 closes switch S2, thereby creating a resonant circuit comprised of capacitor Cl and coils 5, 6 or 7, 8. The resultant AC signal is an under-damped ring-down pulse which is applied to the magnetic core deactivator for deactivating the EAS marker.

For the purposes of the present invention, the under-damped ring-down pulse preferably has a peak value of 100 volts and a frequency of between about 100 Hz to 2,500 Hz. It should be appreciated by those skilled in the art, however, that for proper deactivation, the frequency of the ring-down degaussing waveform need only be more rapid than the motion of the EAS marker in front of the magnetic core deactivator. Further, the invention is not so limited by the particular frequency disclosed. For example, as the clerk moves the article containing the EAS marker to be deactivated in front of the boot 15, the frequency of the ring- down degaussing waveform should result in a varying magnetic field which changes at a rate which is higher than the motion of the EAS marker across the face of boot 15 as the label is scanned. Moreover, the specific frequency of the degaussing waveform can vary according to the physical characteristics of the EAS marker itself, as well as the physical characteristics of the magnetic core deactivator and its Q. Similarly, the peak voltage applied and the intensity of the magnetic field will vary depending upon the particular EAS markers which may be used. Fig. 4 is a block diagram for the invention showing interface and control circuit 23 operatively connected to drive circuit blocks 19 A, 19B which together comprise drive circuit 19. In a preferred embodiment, the drive circuit blocks 19 A and 19B are each comprised of a drive circuit similar to that described above relative to Fig. 2, although the invention is not limited in this regard. The deactivation cycle is preferably controlled by interface and control circuit 23. The interface and control circuit 23 can be contained within the scanner 17, within boot 15 or in a common housing with drive circuit 19. One or more digital or analog control signals 27, 28 and 29 are preferably received by interface control circuit 23 to indicate a trigger condition for deactivating an EAS marker. For example, control signal 27 indicates that an operator has manually triggered scanner 17 by depressing switch 9 to perform a bar code scan. Alternatively, a control signal 28 can be provided which indicates that the scanner 17 has successfully scanned a bar code on a product package so that EAS deactivation occurs automatically upon the occurrence of a successful bar code read. Finally, control signal 29 can be provided to indicate that an EAS marker detection sensor mounted in either the scanner 17 or within boot 15 has detected the nearby presence of an EAS marker which is to be deactivated. Any one or more of these control signals can be used to trigger EAS deactivation within the scope of the present invention. In any case, each occurrence of a trigger signal 27, 28 or 29 preferably will prompt interface and control circuit 23 to initiate at least one deactivation cycle, comprising in each case the discharge of capacitor C 1 to apply a ring-down pulse as described above to each of the respective sets of coils 5,6 and 7, 8.

A trigger select control 25 can be provided to allow an operator to select which of the control inputs 27, 28 and 29 are to be used in any particular installation to trigger the deactivation of EAS markers. Those skilled in the art will appreciate that the trigger select control 25 can be a set of conventional analog switches or may be a microprocessor control interface for controlling a microprocessor contained within the interface and control circuit.

Finally, it should be noted that in Fig. 4, coils 5, 6, 7 and 8 are shown connected in parallel configuration to drive circuitry blocks 19 A and 19B . However, it will be appreciated that the invention is not so limited. In an alternative embodiment, coil pairs 5, 6 could be connected in series, as could coil pairs 7, 8.

Fig. 4 is a flow chart illustrating the operation of control and interface circuit 23, and further, a method of using the magnetic core deactivating system (system) disclosed herein. The system, adapted for use with the hand-held scanner 17, can automatically deactivate the EAS marker. The system is capable of responding to various control signals. Specifically, such control signals can trigger the drive means 21 to activate, thereby energizing the magnetic core deactivator 21.

The system disclosed herein, remains in a waiting condition for triggering the activation of the drive circuitry 19. Beginning with step 50, the magnetic core deactivating system determines whether a valid EAS marker has been detected as indicated by control signal 29. Detection of a valid EAS marker in close proximity to the hand-held scanner 17 indicates that an article having such a marker is about to be scanned or has been scanned for purchase. Thus, the marker must be deactivated before the customer may leave with the article so as not to set off any EAS system alarms . If an EAS marker has been detected by the detection circuitry, then the system proceeds to step 55 in which the interface and control circuit 23 sends a control signal to drive circuits 19A and 19B for energizing the magnetic core deactivator in step 85.

If no EAS marker is detected in step 50 then in step 60 the interface and control circuit determines if a bar code detect signal 28 is received indicating that a valid bar code, or other information upon a label, has been read by the hand-held scanner 17. If so, then the system proceeds to step 65. It should be appreciated that the reading of a valid bar code indicates that an article containing an EAS marker is in close proximity to the hand-held scanner. Once an article is scanned by a clerk or operator for purchase by a customer, the EAS marker must be deactivated before the article can be taken from the store. Thus, in step 65, the interface and control circuit 23 sends a control signal to drive circuits 19A and 19B for energizing the deactivation core 21.

If no valid bar code is detected in step 60, then the system proceeds to step 70. If the interface and control circuit 23 receives a manual trigger detect signal 27 indicating that a manual scanner trigger has been activated, then the system proceeds to step 75 which sends a control signal to drive circuit 19 to energized the deactivation core. It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application. The invention can take other specific forms without departing from the spirit or essential attributes thereof. Accordingly, reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims

CLAIMS What is claimed is:

1. An extended range magnetic core deactivating system (system) for deactivating an electronic article surveillance (EAS) marker comprising: a magnetic core deactivator having a picture frame geometry, adapted to be mounted on a hand-held scanner, capable of transmitting a degaussing waveform for deactivating said EAS marker.

2. The system of claim 1, wherein said hand-held scanner has an optical scanner integrated within a scanning end thereof and said magnetic core deactivator is formed to securely fit around a perimeter of said scanning end to perform EAS deactivation without interfering with the operation of said optical scanner.

3. The system of claim 1, wherein said magnetic core deactivator is comprised of: a first, second, third, and fourth core elements, each of said core elements having at least one winding of wire, and said first and second core elements having an orthogonal orientation relative to said third and fourth core elements.

4. The system of claim 3, wherein said first and second core elements have the same magnetization orientation, and said third and fourth core elements have the same magnetization orientation.

5. The system of claim 3, wherein said first, second, third, and fourth core elements are of substantially equal length.

6. The system of claim 3, wherein each of said first, second, third, and fourth core elements have balanced excitation levels.

7. The system of claim 3, wherein said first and said second core elements are substantially equivalent in length, said third and said fourth core elements are substantially equivalent in length, said first and said second core elements being longer than said third and said fourth core elements.

8. The system of claim 7, wherein each of said first, second, third, and fourth core elements have balanced excitation levels.

9. The system of claim 1, wherein said system is further comprised of marker detection circuitry responsive to a signal indicating the presence of said EAS marker to trigger said magnetic core deactivator to automatically emit said degaussing waveform.

10. The system of claim 1 , wherein said system is further comprised of control circuitry responsive to said hand-held scanner reading a bar code, to automatically trigger said magnetic core deactivator to emit said degaussing waveform.

11. The system of claim 1 , wherein said system, responsive to a manual triggering means, automatically emits said degaussing waveform.

12. The system of claim 3 , wherein said first and said second core elements are energized in an alternating fashion with said third and said fourth core elements.

13. A method for deactivating an EAS marker comprising: receiving a signal from a triggering means in a bar code scanner; in response to said signal, automatically energizing a picture frame geometry magnetic core deactivator capable of transmitting a degaussing waveform for deactivating said EAS marker; and, emitting said degaussing waveform from said picture frame geometry magnetic core deactivator.

14. The method of claim 13, wherein said signal is generated in response to the detection of said EAS marker.

15. The method of claim 13, wherein said signal is generated in response to the reading of a bar code by said hand-held scanner.

16. The method of claim 13, wherein said triggering means is manually activated.

17. The method of claim 13, wherein said automatic energizing step includes energizing said first and said second core elements in an alternating fashion with said third and said fourth core elements.