HK1028126A - Deactivation device with biplanar deactivation - Google Patents

Description

Demagnetizing device using biplanar demagnetization

The present invention relates generally to a demagnetizing device used in electronic article surveillance ("EAS") systems, and more particularly to a demagnetizing device that utilizes a bi-planar demagnetization action to demagnetize EAS markers or tags used in EAS systems.

In current EAS systems, an EAS tag or label is placed on an article and if an unauthorized attempt is made to remove the article with a valid EAS tag, it is detected by the EAS system. One type of EAS marker includes a length of amorphous magnetic material disposed substantially parallel to a length of magnetizable material used as a control element. When a valid marker, i.e. a marker having a magnetized control element, is placed in an alternating magnetic field that defines an interrogation zone, the marker produces a detectable valid marker signal. When a tag is deactivated by demagnetizing its control element, the tag no longer produces a detectable tag signal. This demagnetization of the marker may occur, for example, when an employee of a retail store passes an item having an EAS marker through a demagnetization device at a checkout counter, thereby deactivating the marker.

Generally, the tag demagnetization device includes a coil structure that can be energized to generate a magnetic field of sufficient magnitude to deactivate the tag. In other words, the tag no longer provides an output alarm or sends an alarm condition to an alarm device external to the tag in response to the incident energy provided thereto.

Examples of demagnetizing devices include those commercially available from sensory electronics corporation of Boca Raton, Florida under the trademarks Speed Station  and Rapid Pad . A RapidPad  demagnetizing device that generates a magnetic field when detecting a marker has one or planar coils disposed horizontally within a housing. Demagnetization occurs when the mark is detected to move in a coplanar configuration within 4 inches of the upper surface of the housing at the top of the check counter.

The Speed Station  demagnetization device has a housing containing 6 coils that are orthogonally arranged within the housing to form a "bucket" configuration. An employee inserts one or more items into the open side of the bucket. The employee then demagnetizes the inserted item by manually activating the demagnetization device.

The Speed Station  demagnetization device includes 6 coils divided into 3 coil pairs that are arranged around the bucket with respect to the x, y, z axis plane. The coils of each coil pair are arranged parallel to each other and the coils of one pair are sequentially driven at a time to demagnetize the EAS marker in 3 steps. Because the coils are in 3 planes, there is no need for a marker to be oriented with respect to the coils, but the marker is required to be inserted into the cavity of the bucket for demagnetization.

The above-described demagnetizing devices are limited to use within their demagnetizing regions, or the demagnetizing regions used to demagnetize EAS markers are limited to the height and area of the planar coil structure of each demagnetizing device. For example, when using a Rapid Pad  demagnetizing device, the demagnetizing regions used to demagnetize the indicia are only present in a horizontal or coplanar direction and within about 4 inches of the top surface of the housing of the demagnetizing device. This requires the operator to ensure that the tag is near the surface of the Rapid Pad  demagnetizing device in order to ensure that the tag is demagnetized. With respect to the Speed Station  demagnetization device, its demagnetization zone exists only inside its "bucket" configuration, thus requiring a marker to be inserted therein.

Because of the limited extent or area of the demagnetization zone of each device, demagnetization of a mark affixed to an article is sometimes ineffective when the position of the mark is inappropriate relative to the demagnetization device used. This can cause undesirable false alarms for EAS systems.

It is therefore an object of the present invention to provide an improved demagnetizing device for demagnetizing EAS markers.

It is another object of the present invention to provide a demagnetization device that can increase or extend the range or area in which EAS marker demagnetization can be performed.

It is an additional object of the present invention to provide a demagnetization device that is simple in construction and easy to use for performing the demagnetization of an EAS marker.

In accordance with the principles of the present invention, the above and other objects are accomplished by a demagnetizing device for demagnetizing an EAS marker, the device including a demagnetizing coil having first and second coil portions. The first coil portion and the second coil portion are adjacent at an angle and the coil portions are adapted to transmit a demagnetizing field simultaneously. The demagnetizing field forms a demagnetizing zone that enables an active EAS marker to be demagnetized when located within the demagnetizing zone.

In the embodiments of the invention described later, the first and second coil portions of the demagnetization coil are separate independent coils located in the housing. The first coil portion is located at a side of the housing and forms an angle in a range of 45 degrees to 135 degrees with respect to a plane of the second coil portion located at an adjacent bottom of the housing.

According to this configuration, the active EAS tag is demagnetized when the active EAS tag is proximate to the demagnetization device and when the demagnetization field is simultaneously emitted from the first and second coil portions. The demagnetizing device of the present invention provides a large area or area for an operator to place an active EAS marker to be demagnetized and is capable of positioning the marker in any of a variety of different orientations that enable the demagnetization zone formed by the device to be demagnetized.

In a modification of the demagnetization device in accordance with the invention, the demagnetization coil is a coil bent to define the side and the bottom of the first and second adjacent coil parts, respectively. The curved coil structure also provides a larger demagnetizing field and enables an active EAS marker to be positioned in any of the different directions in which the demagnetizing field demagnetizes.

The above and other features and aspects of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 is a demagnetizing device in accordance with the principles of the present invention;

FIG. 2 is a block diagram of the demagnetizing device of FIG. 1;

FIG. 3 shows details of an EAS marker utilizing the demagnetizing device of the present invention;

FIGS. 4A-4D illustrate examples of the resulting demagnetizing fields of the coils of the demagnetizing device of FIG. 1;

FIGS. 5A-5C show circuit diagrams of transistors for each phase of the demagnetization device of FIG. 1;

FIG. 6 shows a modified embodiment of the demagnetization device according to the invention; and

fig. 7 is a block diagram of the demagnetization device of fig. 6.

As shown in FIG. 1, the demagnetizing device 10 of the present invention is used to demagnetize EAS markers used in an EAS system. The demagnetizing device 10 is capable of performing EAS marker demagnetization by increasing the extent or area of the entire demagnetizing region in which the marker may be demagnetized. The deactivation device 10 also enables deactivation of EAS markers located at different orientations within the deactivation zone.

As shown in fig. 1, the demagnetization device 10 of the present invention includes a demagnetization unit 12 and an excitation or power supply unit 2. The demagnetization unit 12 comprises a first and a second coil part, which form a first demagnetization coil 14 and a second demagnetization coil 16, respectively, inside a housing 18. The housing 18 has a cavity 40 formed by sides 42 and a bottom 44. The first and second demagnetization coils 14 and 16 are shown having a square configuration, respectively in the side 42 and bottom 44 of the cavity 40 of the housing 18, so as to be in an angularly adjacent relationship to each other.

Preferably, the first demagnetization coil 14 is arranged such that its plane is at an angle in the range of 45 degrees to 135 degrees in relation to the plane of the second demagnetization coil 16. As shown in fig. 1, coils 14 and 16 are adjacent to each other, approximately 90 degrees or in a perpendicular relationship. However, the coils 14 and 16 are not limited to this angular range and may be at different angles depending on the shape of the desired demagnetization field formed by the demagnetization device 10.

The coils 14 and 16 are adapted to transmit their respective magnetic fields simultaneously. In this way, a composite magnetic field is formed from the individual magnetic fields of the coils. The resultant magnetic field, in turn, provides an enhanced mechanism for altering the magnetic properties of an effective EAS marker, such as that shown in fig. 3, placed in proximity to the coil.

The power supply unit 2 controls the operation of the demagnetization unit 12 in such a way that the first and second demagnetization coils 14 and 16 are energized simultaneously. The power supply is connected to the unit 12 by a cable 32 and comprises an electronic circuit part 7 and a power supply 8.

Fig. 2 shows the demagnetization device 10 in detail in the form of a block diagram. The device 10 defines a demagnetizing field 20 that can demagnetize the marks 9. Fig. 3 shows a typical EAS marker 9 that may be demagnetized by a demagnetization device 10.

As shown in fig. 3, the marker 9 comprises a magnetostrictive amorphous element 9A contained in an elongated housing 9B in the vicinity of a control element 9C, which may be constructed of a biasable magnetized material. This type of marker is commercially available from sensory electronics corporation of Boca Raton, Florida under the Ultra trademark^*Max^. The characteristics and operation of a tag similar to the demagnetizable tag 9 are described in us patent 4510489, which is incorporated herein by reference.

During operation of the demagnetization device 10, the microprocessor 22 receives an input signal via input line 30 indicating that there are marks in the demagnetization device that are to be demagnetized. The signal 30 may be generated in the same manner as in a prior art demagnetizing device, such as that described in U.S. patent 5341125, the contents of which are incorporated herein by reference. Such a demagnetization device comprises a transmission/reception coil and associated processing circuitry (not shown) for detecting the presence of a mark in the demagnetization zone 20 and thus providing a line signal 30.

After receiving the line signal 30, the microprocessor 22 initiates the demagnetization process of the demagnetization device 10 by closing the discharge switch 24. This connects the output of the high power generator 26 to the first and second demagnetization coils 14, 16. Current then flows through the first and second demagnetization coils 14 and 16. This causes the coils to simultaneously emit electromagnetic fields and form a resultant demagnetizing field in the demagnetizing zone 20. The resulting demagnetizing field creates magnetic field lines along the length of the magnetizable control elements 9C of the labels 9, thereby demagnetizing the elements.

The resulting demagnetizing field will demagnetize the elements 9C of the marks 9 regardless of the orientation of the marks with respect to the demagnetization device 10, as long as the marks 9 are located at a demagnetizing position in the demagnetizing zone. For example, the demagnetized regions 20 produced by demagnetizing device 10 may range from the surface of device 10 to 8 to 10 inches from the surface.

Fig. 4A-4D are diagrammatic views of the first and second demagnetization coils 14 and 16 and the resulting demagnetization field formed in the demagnetization zone 20 created by these coils. Fig. 4A shows a general structure of the first demagnetization coil 14 (coil 1) and the second demagnetization coil 16 (coil 2) in an adjacent angle orthogonal relationship. Fig. 4B shows the configuration of the demagnetized regions 20 formed when each coil generates a magnetic field. In this case, the magnetic fields of the coils add vectorially, resulting in a composite demagnetizing field that is greater than each individual magnetic field. The area 20 defined by the resultant demagnetizing field helps to create a wider and larger area for demagnetizing the marks. To create this larger demagnetized region 20, for example, the first and second demagnetizing coils 14 and 16 can be energized in phase in a repetitive manner, as shown in FIG. 4C, or out of phase, as shown in FIG. 4D. For the in-phase mode, the first and second demagnetization coils 14 and 16 have magnetic field vectors 54 and 56, respectively, which start from the first demagnetization coil 14 into the second demagnetization coil 16, as shown in fig. 4C. In a different phase manner, the first and second demagnetization coils 14 and 16 have magnetic field vectors 50 and 52, which are output from the first and second demagnetization coils 14 and 16, respectively, as shown in fig. 4E. So that the coils 14 and 16 cycle in and out of phase to help establish this larger demagnetized region 20.

Fig. 5A-5C illustrate a circuit for the demagnetization device 10, which circuit is capable of "cycling" or alternating the magnetic field generated in the demagnetization zone. The circuit diagram of fig. 5A-5C shows 4 transistors (Q1, Q2, Q3, Q4) that operate as switches for the demagnetization device 10. As shown in fig. 5A, when the capacitor bank 200 is charged, the transistor is turned off. As shown in fig. 5B, when the capacitor bank 200 is fully charged, the transistors Q1, Q4 are turned on at a certain time, and a voltage is applied to the coil 14 (coil 1) and the coil 16 (coil 2). When the current i rises, a first discharge path is formed through the coil, thereby causing the coil to generate a magnetic field, forming a resultant demagnetizing field in the demagnetizing zone 20.

After a predetermined time interval determined by the microprocessor 22, the transistors Q1 and Q4 are turned off, and the transistors Q2, Q3 are turned on, as shown in fig. 5C. Transistors Q2, Q3 are turned on so that an opposite discharge path is formed through the coil, thereby reversing the polarity of the voltage applied to the coil to reverse the current and associated magnetic field. After each successive cycle of switching the transistor pair Q1, Q4 and Q2, Q3, the time between transitions is reduced. This generates a "cyclic" or alternating magnetic field of decreasing intensity in the demagnetization zone 20, thereby demagnetizing the marks 9.

A variant of the demagnetization device 10 is shown in fig. 6. In this case, the apparatus 10 comprises a curved demagnetization coil 100 having a side part 102 and a bottom part 104 for defining a first and a second coil part. An excitation unit or power supply unit 2 is used to drive the coil 100.

As can be seen in fig. 6, the coil 100 is bent to form a "cradle" or "L" shape, wherein the sides 102 of the coil 100 are bent at least 40 degrees relative to the bottom 104. The excitation unit 2 excites the curved demagnetization coil 100, providing a demagnetization zone 20, as shown in fig. 7, similar to the demagnetization zones provided by the first and second demagnetization coils 14 and 16 of fig. 1 and 2. The increase in height and area provided by the sides 102 and the bottom 104 helps to create a larger demagnetizing zone to enable easy demagnetization of the mark 9.

The first and second demagnetization coils 14 and 16 of the present invention shown in fig. 1 and the meander coil 100 shown in fig. 7 are not limited to the configurations shown, but may have different angles, and may have different shapes, sizes and dimensions depending on the desired demagnetization zone. The coils 14 and 16 of fig. 1 and the coil 100 of fig. 6 may also be manually manipulated with other means capable of triggering the demagnetization device to demagnetize the marked article.

The demagnetization device 10 is also not limited to use with a tag 9 of the kind described above, but can be used for a variety of different tags in electronic article surveillance systems, such as magnetic tags, radio frequency tags, etc., depending on the type of coil and the desired phase structure.

The housing 12 for the coil may be made of various materials, but is preferably injection molded from a non-magnetic material such as polystyrene or polycarbonate. However, in addition to the housings shown in fig. 1 and 6, the coils 14 and 16 and the coil 100 may be housed in different housings or may operate without a housing or support. For example, coils 14 and 16 and 100 may be included in a check-out counter or other structure of a department requiring a demagnetization device.

In all cases it is understood that the above-described arrangements are merely illustrative of the many possible specific embodiments which represent applications of the present invention. Various changes and modifications can be made without departing from the scope and spirit of the invention.

Claims (35)

1. A demagnetization device for demagnetizing an electronic article surveillance ("EAS") marker, the device comprising:

a demagnetization coil having a first coil portion and a second coil portion, the first coil portion and the second coil portion being arranged in an angularly adjacent relationship, and the first and second coil portions being adapted to simultaneously transmit a demagnetization field, the demagnetization field forming a demagnetization zone, the demagnetization zone being configured to allow a valid EAS marker to be demagnetized when located within the demagnetization zone.

2. The apparatus of claim 1, wherein a plane of the first coil portion is at an angle in a range of 45 degrees to 135 degrees relative to a plane of the second coil portion.

3. The apparatus of claim 2, wherein a plane of the first coil portion is at a 90 degree angle relative to a plane of the second coil portion.

4. The apparatus of claim 2 wherein the demagnetization apparatus further comprises a housing for receiving and holding the first and second coil parts of the demagnetization coil.

5. The device of claim 4, wherein the housing has a cavity with sides and a bottom, the first coil portion being located at the sides and the second coil portion being located at the bottom.

6. An apparatus according to claim 4, wherein said first and second coil portions are formed as first and second separate coils, said apparatus further comprising an excitation unit for exciting said separate coils simultaneously.

7. The apparatus of claim 6, wherein the excitation unit excites the first and second individual coils in and out of phase in a repetitive manner.

8. The apparatus of claim 4, wherein the demagnetization coil is a bent coil, the first coil portion and the second coil portion comprise a side portion and a bottom portion of the bent coil, respectively, and the apparatus comprises an excitation unit for exciting the bent coil.

9. The apparatus of claim 1, wherein the first and second coil portions are formed as first and second separate coils.

10. The apparatus of claim 9, further comprising an excitation unit for simultaneously exciting the first and second separate coils.

11. The apparatus of claim 10, wherein the excitation unit excites the first and second individual coils in and out of phase in a repetitive manner.

12. The apparatus of claim 1, wherein the demagnetization coil is a bent coil, and the first coil portion and the second coil portion include a side portion and a bottom portion of the bent coil, respectively.

13. The apparatus of claim 12, further comprising an excitation unit for exciting the bending coil.

14. A method of demagnetizing electronic article surveillance ("EAS") markers using a demagnetization device, comprising the steps of:

placing an active EAS marker at a deactivation position proximate to the deactivation device;

simultaneously transmitting a demagnetizing field from first and second coil portions of a demagnetization coil of a demagnetization device to demagnetize the active EAS marker, the first coil portion and the second coil portion being disposed in an angularly adjacent relationship; and

a demagnetization zone is formed by the demagnetization fields transmitted from the first and second coil portions, the demagnetization zone being configured to allow demagnetization of a valid EAS tag when the valid EAS tag is placed in a demagnetization location within the demagnetization zone.

15. The method of claim 14, wherein the plane of the first coil portion has an angular range of 45 degrees to 135 degrees relative to the plane of the second coil portion.

16. The method of claim 15, wherein the plane of the first coil portion is at a 90 degree angle relative to the plane of the second coil portion.

17. The method of claim 15, wherein the first and second coil portions are formed as first and second separate coils, and further comprising the step of energizing the separate coils simultaneously.

18. The method of claim 17, wherein the energizing step comprises energizing the first and second individual coils in-phase and out-of-phase in a repeating manner.

19. The method of claim 15, wherein the demagnetization coil is a bent coil, the first coil portion and the second coil portion respectively comprise a side and a bottom of the bent coil, and the method further comprises a step for exciting the bent coil.

20. The method of claim 14, wherein the first and second coil portions are formed as first and second separate coils.

21. The method of claim 20, further comprising a step for simultaneously energizing the first and second separate coils.

22. The method of claim 21, wherein said energizing step energizes said first and second individual coils in phase and out of phase in a repetitive manner.

23. The method of claim 14, wherein the demagnetization coil is a bent coil, and the first coil portion and the second coil portion comprise a side portion and a bottom portion of the bent coil, respectively.

24. The method of claim 23, further comprising a step for energizing the bending coil.

25. A system for demagnetizing electronic article surveillance ("EAS") markers using a demagnetization device, comprising:

a) an active EAS marker;

b) a demagnetization coil for demagnetizing an active EAS marker, the demagnetization coil having a first coil portion and a second coil portion, the first coil portion and the second coil portion being disposed in an angularly adjacent relationship, the first and second coil portions being adapted to simultaneously transmit a demagnetization field, the demagnetization field forming a demagnetization zone, the demagnetization zone being configured to allow demagnetization of an active EAS marker when the active EAS marker is disposed therein.

26. The system of claim 25, wherein the plane of the first coil portion has an angular range of 45 degrees to 135 degrees relative to the plane of the second coil portion.

27. The system of claim 26, wherein a plane of the first coil portion is at a 90 degree angle relative to a plane of the second coil portion.

28. The system of claim 26, wherein the first and second coil portions are formed as first and second separate coils, and the apparatus further comprises an excitation unit that excites the separate coils simultaneously.

29. The system of claim 28, wherein the excitation unit comprises exciting the first and second individual coils in-phase and out-of-phase in a repeating manner.

30. The system of claim 26, wherein the demagnetization coil is a bent coil, the first coil portion and the second coil portion comprise a side portion and a bottom portion of the bent coil, respectively, and the apparatus further comprises an excitation unit for exciting the bent coil.

31. The system of claim 25, wherein the first and second coil portions are formed as first and second separate coils.

32. The system of claim 31, wherein the apparatus further comprises an excitation unit for simultaneously exciting the first and second separate coils.

33. The system of claim 32, wherein the excitation unit excites the first and second individual coils in-phase and out-of-phase in a repetitive manner.

34. The system of claim 25, wherein the demagnetization coil is a bent coil, and the first coil portion and the second coil portion include a side portion and a bottom portion of the bent coil, respectively.

35. The system of claim 34, wherein the apparatus further comprises an excitation unit for exciting the bending coil.