HK1139232B - Electronics eas tag detection and method - Google Patents

Description

Electronic EAS tag detection and method

Technical Field

The present invention relates to electronic article surveillance ("EAS") systems, and more particularly to a tag deactivator for an EAS system.

Background

EAS systems are designed to prevent unauthorized removal of items from a controlled area. In a typical EAS system, tags designed to interact with an electromagnetic field located at an exit of a controlled area are attached to articles to be protected. If the tag is brought into an electromagnetic field or "interrogation zone," the presence of the tag is detected and appropriate action is taken. For a controlled area, such as a retail store, the appropriate action taken for detection of an EAS tag may be the generation of an alarm. Some types of EAS tags remain attached to the protected article but are deactivated by a deactivator device prior to authorized removal from the controlled area, which changes the characteristics of the tag so that the tag is no longer detectable in the interrogation zone.

Most EAS tag deactivation devices are fixed in a particular location, such as near a point of sale ("POS") station of a retail environment. If an item is purchased and for some reason the attached EAS tag is not deactivated at the deactivator adjacent the POS station, the EAS tag will raise an alarm at the store exit. Then to deactivate the EAS tag, the article must be brought back to the deactivator adjacent the POS station, which can cause confusion and embarrassment to the consumer. Handheld deactivators, sometimes referred to as "boot deactivators," for EAS tags are part of known handheld barcode scanners, but consist only of passive demagnetizing magnets of alternating polarity. These devices do not provide feedback to the user whether an active tag is present or whether the deactivation attempt was successful. Fully functional proximity handheld deactivators are excellent at deactivation, but at the expense of increased weight, manufacturing and purchase price, and complexity.

A typical handheld barcode scanner with a boot deactivator is a passive device and must contact or be in close proximity to deactivate an EAS tag. As the use of source tagging expands, i.e., the application of EAS security tags at a source, such as at the manufacturer of merchandise, the EAS tag will be located somewhere on the item or its packaging. Because a user cannot see a tag when it is hidden somewhere on an item or its packaging, the user cannot determine whether all EAS tags associated with the article have been deactivated. Thus, another limitation of current boot deactivators is that the user does not receive feedback from the boot deactivator as to whether the EAS tag has been deactivated or whether it remains active. Many times, a user will "brush" the product or its packaging several times with a handheld deactivator in the hope of deactivating all associated EAS tags. Often times, the user will be forced to lift a bulky or large size box and deactivate using a powerful desktop deactivator. This takes time and extra effort at the point of sale. Accordingly, there is a need for an improved EAS deactivation device, such as a boot deactivator with user observable feedback, to indicate when an EAS tag has been deactivated.

Disclosure of Invention

The present invention advantageously provides circuits, devices and methods for electronic article surveillance ("EAS") tag detection, deactivation and EAS tag activation status indication.

In accordance with one aspect, the present invention provides an electronic circuit for an electronic article surveillance ("EAS") device. The electronic circuit includes a coil that induces a current when subjected to an electromagnetic field. The coil is also used to transmit electromagnetic tag signals. The tuning capacitor is in electrical communication with the coil. The tuning capacitor and coil establish resonance to transmit the electromagnetic tag signal. The storage capacitor is in electrical communication with the coil. The storage capacitor receives the induced current from the coil for later supply of energy to the electronic circuitry.

In accordance with another aspect, the present invention provides an apparatus for detecting and deactivating an EAS tag. The device includes a housing securable to at least one of a barcode scanner and a radio frequency identification ("RFID") scanner/reader. The electronic circuit is located within the housing. At least one user observable indicator is controlled by the electronic circuit. A user observable indicator is secured to the housing and provides a tag deactivation status. Exemplary indicators can be visual, such as LEDs, and/or audible, such as piezoelectric devices or speakers.

In accordance with yet another aspect, the present invention provides a method for generating a deactivation state for an electronic article surveillance ("EAS") tag in which a power storage device of an electronic circuit is inductively charged. Communication with the at least one EAS tag is established when the electronic circuit is operated using energy stored in the energy storage device. When communicating with the EAS tag, inductive charging of the energy storage device is inhibited.

Brief Description of Drawings

A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagram of an EAS system constructed in accordance with the principles of the present invention for scanning a barcode of an item and deactivating an EAS tag;

FIG. 2 is a perspective view of a boot deactivator for use with the EAS system of FIG. 1 and constructed in accordance with the principles of the present invention;

FIG. 3 is a schematic diagram of an exemplary electronic circuit of a boot deactivator constructed in accordance with the principles of the present invention;

FIG. 4 is a flow chart illustrating an exemplary logical process for the electronic circuit shown in FIG. 3 in accordance with the principles of the present invention; and

fig. 5 is a flow chart of an exemplary tag detection and deactivation process in accordance with the principles of the present invention.

Detailed Description

Referring now to the drawing figures in which like reference designators refer to like elements, there is shown in FIG. 1 a diagram of an exemplary system constructed in accordance with the principles of the present invention and designated generally as "100". Electronic article surveillance ("EAS") system 100 includes a monitoring system that creates a system detection zone, also referred to as an "interrogation zone," at the entrance to a controlled area (not shown). Upon entering the interrogation zone, the active EAS tag creates interference in the zone, which interference is detected by the receiver of EAS system 100. EAS systems, such as EAS system 100, range from very low magnetic field frequencies through the radio frequency range. These different frequencies play a role in establishing characteristics that affect operation. The EAS system 100 includes a handheld barcode scanner 102 and a boot deactivator 104. In this embodiment, the boot deactivator 104 is attached near the tip portion 106 of the barcode scanner 102, which is shown as a gun scanner. Of course, the arrangement of the boot deactivator 104 is not limited to the tip 106 of the gun barcode scanner 102, but can also be mounted in various locations, such as along the end of the hand-held portion of the gun barcode scanner 102.

Further, boot deactivator 104 is not limited to a gun type scanner, but can be connected to other handheld deactivators and devices, such as a tag lockers or RFID scanners (also referred to as RFID readers). EAS system 100 further includes one or more security tags or EAS labels 108 located somewhere on article 110 or its packaging. EAS tag 108 may be a source tag that is not necessarily located on the outer surface of article 110. The EAS system 100 can further include a charging pad (not shown) for recharging the power source of the barcode scanner 102 and/or the boot deactivator 104. For example, the charging pad can be located at a POS checkout stand with a desktop price scanner.

In operation, the boot deactivator 104 can synchronously deactivate the EAS tag 108 when the scanner 102 scans the item 110 for checkout. For example, the boot deactivator 104 can deactivate the EAS tag 108 when the tip 106 of the scanner 102 is pressed against the tag 108 or very close to the tag 108. Because the boot deactivator 104 is attached to the portable handheld scanner 102, deactivation of tags or EAS tags on bulky or bulky items becomes easier. For example, in situations where the cargo is too heavy or bulky, such as a large widescreen television set in a large box and/or several boxes of potable water on a shopping cart, the clerk cannot place it on the table deactivator. In this example, handheld scanner 102 with boot deactivator 104 provides the convenience of deactivating tags 108 located inside boxes or on the surface of these boxes without requiring a clerk to lift the boxes and place them on a desktop deactivator to deactivate tags 108.

FIG. 2 shows the handheld boot deactivator 104 of FIG. 1 in greater detail. In this embodiment, boot deactivator 104 includes a housing 202 defining an opening 204 and an electronics compartment 206. The housing 202 of the boot deactivator 104 can be made of any suitable material, including plastic or metal. The electronic compartment 206 of the housing 202 provides an area for placement of electronic circuitry 300 (fig. 3) for EAS tag detection, EAS tag deactivation and EAS tag deactivation status generation. The electronics compartment 206 can be an integral part of the housing 202, a recessed area within the housing 202, or a separate protective structure configured to mate with the housing 202. The electronic circuit 300 can be incorporated into the electronics compartment 206 as shown in fig. 2, or the electronic circuit 300 can be a separate device and separate from the electronics compartment 206. The opening 204 provides an unobstructed scanning window for the scanner 102 (fig. 1). Thus, when scanner 102 generates a scanning beam, such as a laser beam used to scan a bar code of item 110, the beam is not blocked or obscured by boot deactivator 104.

The boot deactivator 104 further includes one or more deactivation status indicators 208, 210. In this embodiment, indicator 208 is a visual indicator, such as a light emitting diode ("LED"), and/or indicator 210 is an audible indicator, such as a speaker that produces an audible signal, tone, or sound. For example, a green LED208 on the boot deactivator 104 alerts the user when an active EAS tag 108 is detected, and the speaker 210 may generate a tone, such as a "beep," to indicate that deactivation of the tag 108 has been attempted. If no sound or no LED is illuminated after this tone, this means that the EAS tag 108 was successfully deactivated. It is contemplated that the status indicators 208 and 210 can be any type of indication method, including a vibrator, an LED, a speaker, and the like. The deactivation status indicator can be a user observable indicator that can be incorporated into or affixed to the housing 202, in a recessed area of the housing 202 or in a separate protective structure arranged to mate with the housing 202.

Referring to FIG. 3, FIG. 3 is a schematic diagram illustrating an exemplary electronic circuit 300 of an EAS system that can be used with the boot deactivator 104 (FIG. 2). The electronic circuit 300 can be located in the electronic compartment 206 (fig. 2) and incorporated into the boot deactivator 104 to perform EAS tag deactivation and EAS tag deactivation status indication. The dimensions of the electronic circuit 300 and the electronic compartment 206 are sufficiently small that the electronic circuit 300 is easily incorporated into the boot deactivator 104.

The exemplary electronic circuit 300 includes a magnet 302 coupled to a charging/transceiving coil 304. When the magnet 302 and the charging/transceiver coil 304 are placed in the electromagnetic field of the charging pad or table top deactivator, an alternating current ("AC") is induced in the charging/transceiver coil 304. The induced alternating current is rectified by a diode 306, such as a silicon controlled rectifier ("SCR") diode, which automatically commutates the alternating current to produce a unidirectional current, i.e., direct current ("DC"), for charging an energy storage supercapacitor 308 and/or an optional small battery 310. In this embodiment, the SCR diode 306 can be a 4-layer solid state device for generating a variable dc voltage from an ac line voltage and for power conversion, phase control, battery charging, and inverter circuits. In addition, the SCR diode 306 is used to maintain a constant output current or voltage of the electronic circuit 300. In this embodiment, a storage capacitor 308, such as a supercapacitor, and/or an optional battery 310 are connected in parallel with each other, and either of them can selectively serve as a power source for the electronic circuit 300. As previously mentioned, battery 310 is optional in that one embodiment of electronic circuit 300 uses an inductive charging method to charge its power source.

The electronic circuit 300 divides and regulates the bus voltage source V through a voltage divider 312 using a capacitor 308 and/or a battery 310 as the bus voltage source V, such as 5V. The voltage divider 312 includes a zener diode 314 in series with a resistor 316 and operates to provide a processor voltage, such as 3.3V across the zener diode 314. Generally, zener diode 314 not only allows current to flow in the forward direction, which resembles a conventional diode, but also allows current to flow in the reverse direction when the voltage is greater than the rated breakdown voltage, also referred to as the "zener voltage". Zener diode 314 has a greatly reduced breakdown voltage and regulates the voltage across electronic circuit 300. An optional linear regulator 318 can be used to regulate and/or reduce or pull down the bus voltage on the zener diode supply voltage to a voltage range suitable for driving a digital signal processor ("DSP") 320, such as 1.8V to 3.3V.

The DSP320 is provided for controlling and processing signals to and from the electronic circuit 300. In one embodiment, the DSP320 periodically "wakes up" from the low power mode and transmits a current through the charge/transceiver coil 304 (capacitor 324 and coil 304 from the resonant circuit) via the transmitter driver 322 and the resonant capacitor 324, generating a pulsed interrogation signal that is transmitted to the tag 108. In this embodiment, the transmitted pulses can be at an acousto-magnetic frequency of 58kHz, with a pulse width of less than 1.5ms, and emitted at a repetition rate of 36/30Hz (for 60/50Hz local ac line frequency, respectively), which is selected to minimize interference with the existing 60/50Hz eas system. As mentioned briefly above, when the acousto-magnetic system emits a 58kHz magnetic frequency signal in a pulsed fashion, the emitted signal excites the acousto-magnetic labels in the detection zone. At the completion of the transmit signal pulse, the tag 108 responds by emitting a unique frequency signal. The tag signal can be at the same frequency as the transmitted signal, such as 58 kHz. During the period between pulses, when the transmitter driver 322 is off, the receiver 326 can receive or detect the response signal emitted by the tag 108. Receiver 326 amplifies and filters the response signal of tag 108. Receiver 326 further passes the response signal of tag 108 to a digital-to-analog (a/D) converter of DSP 320.

DSP320 digitally filters the response signal received from tag 108 and analyzes the spectrum of the response signal to obtain a profile of tag 108. The DSP320 also checks the response signal from the tag 108 to ensure that it has the correct tag characteristics, e.g., at the appropriate frequency with the corresponding specified characteristics for synchronization with the transmitter, at the appropriate amplitude level, and at the correct repetition rate. When these criteria occur for successive measurements, then it is highly likely that the tag 108 was detected. This unique tag feature enables the acousto-magnetic technology driven electronic circuit 300 of the present invention to provide broad surveillance coverage, high tag detection rates, and relative immunity to false alarms. When the tag 108 is detected, the DSP320 will trigger an indicator to alert the user by illuminating an LED328 or sending a pulse to a sound transducer 330, such as a piezo-composite transducer or speaker. The LED328 or speaker 330 can be connected directly to the DSP 320.

During the transmit mode, the SCR306 prevents the transferred current from flowing into the supercapacitor 308. During these periods when the electronic circuit 300 is not receiving a response from the tag, the electronic circuit 300 is ready to charge its power supply. Because the charging/transceiver coil 304 and tuning capacitor (or resonant circuit component) 324 are used for electromagnetic signal transmission and inductive charging, the electronic circuit 300 can be charged by a table top deactivator operating at about 58kHz, or a charging pad operating at a frequency of some kHz above and below 58 kHz. Generally, this frequency range does not interfere with the EAS system frequency, but is still suitable for charging capacitor 308.

In operation, the electronic circuit 300 will temporarily activate, look for an EAS tag, and provide a status signal to the user. Using the energy generated by a standard acousto-magnetic table top deactivator and/or charging pad, the electronic circuit 300 is able to be self-powered and thus does not require batteries or battery replacement, which allows the electronic circuit 300 to be a completely environmentally sealed unit. The acousto-magnetic system typically emits a pulsed pattern of 58kHz magnetic frequency signal. The transmitted signal excites an acousto-magnetic EAS tag in the detection zone. When the transmitted signal pulse terminates, the EAS tag responds, emitting a single very unique frequency signal. The frequency of the EAS tag signal is typically the same as the frequency of the transmitter signal, but may vary according to design requirements. Charging of the battery is accomplished by inductive coupling with the acousto-magnetic table top deactivator and/or the charging pad.

In operation, when the boot deactivator 104 receives a response from an EAS tag 108, the electronic circuitry 300 located in the electronic compartment 206 detects whether the EAS tag 108 is deactivated and presents a deactivation status indicator for the EAS tag 108 using any type of indication method. For example, the boot deactivator 104 can also include at least one indicator incorporated into the boot deactivator 104 for indicating the deactivation status of the EAS tag 108. Although FIG. 2 shows the electronic compartment 206 embedded in the bottom of the boot deactivator 104, this is for illustrative purposes as the electronic compartment 206 can be incorporated into the boot deactivator 104 in any configuration without departing from the scope and spirit of the present invention.

The method of inductively charging the supercapacitor 308 to charge the electronic circuit 300 and/or driving the electronic circuit 300 by using the field energy of a table top deactivator or charging pad can also be extended to other point of sale ("POS") equipment, such as hard tag unlockers, EAS double detectors, bar code scanners, and the like. An example of a known 58kHz transmitting charger pad is a desktop deactivator that constantly transmits a detection signal that can be used to charge the electronic circuit 300. In one embodiment, a small battery may be added to the boot deactivator 104 to increase detection range and improve the consistency of device performance. In another embodiment, a method of charging the electronic circuit 300 uses the relative motion of the magnet 302 and the charge/transceiver coil 304 of the boot deactivator 104 to generate a recharge. For example, the magnet 302 coupled to the boot deactivator 104 can be mounted such that it moves in a relatively small area relative to the charging/transceiver coil 304 when the user shakes the boot deactivator 104. When this jolt occurs, a charge is generated by inductively coupling the charging/transceiver coil 304 and the acousto-magnetic magnet 302, thereby inductively charging the supercapacitor 308. In addition, a low energy reservoir, i.e., a low charge on the capacitor 308 or optional battery 310, can be detected by the electronic circuit 300, thereby triggering a low battery status indicator, such as a different pattern of flashing of an LED or an audible alarm different from the tag deactivation indicator.

Fig. 4 is a flow chart illustrating exemplary operations 400 of the electronic circuit 300 for detecting and deactivating an EAS tag and for generating a tag deactivation status indication. In step S402, an induced alternating current is generated by inductive charging. In step S404, the induced ac current is rectified by the diode 306. Next, in step S406, the rectified ac current can charge the energy storage super capacitor 308. The bus voltage is developed at step S408. In step S410, the linear regulator 312 supplies a voltage to drive the DSP 320. The optional linear regulator 312 drops the supply voltage and prevents the delivered current from flowing back into the supercapacitor 308. At step S412, the DSP320 periodically "wakes up" from the low power mode, processing signals transmitted to and received from the EAS tags. At step S414, the DSP320 sends a current through the transmit/receive coil via the transmitter driver 322 (step S414) and the resonant circuit including the resonant capacitor 324 (step S416), generating an interrogation signal that is transmitted to the EAS tag 108. At step S418, if the target tag 108 does not respond to the interrogation signal of the electronic circuit 300 or if the electronic circuit does not detect an EAS tag 108, the process may return to step S402. Otherwise, if there is a response from the EAS tag 108, at S420, the receiver circuit receives the response signal and passes the response signal to the DSP320 for processing the response and any associated data included in the response. The receiver circuit 328 amplifies and filters the tag response signal (step S420) before passing the tag response signal to the DSP320 for processing. Again, the DSP320 processes the tag response signal to determine if the tag response signal is valid and ready for deactivation, and if so, transmits a deactivation signal to the tag 108 (step S422). When the tag response signal is active, the circuit 300 generates a tag status indication using any indicator type, for example, a visual indication such as a green LED, or an audible tone such as a "beep" as discussed above (step S424). The tag interrogation signal and the tag deactivation signal transmitted to the tag 108 via the coil 304 are collectively referred to herein as an electromagnetic tag signal.

Fig. 5 is a flow chart 500 illustrating an exemplary method for deactivating an EAS tag 108. At step S502, upon the occurrence of a predetermined event, the electronic circuit 300 for EAS tag deactivation and EAS tag detection status indication is activated. Upon completion of the activation of the electronic circuit 300, the electronic circuit 300 looks for an EAS tag 108 by generating an interrogation signal (step S504). Upon receiving the correct transmitted interrogation frequency, the tag 108 resonates and can be detected. A typical interrogation frequency for an acousto-magnetic tag is about 58kHz, which will be used as an example herein. At step S506, the electronic circuit 300 receives a resonant response with associated tag data from the EAS tag 108. At step S508, the electronic circuit 300 processes the response signal with the associated tag data to determine whether the response signal is a valid EAS tag signal by examining the associated tag data for various attributes. For example, the response signal must have the proper spectral content and must be received in successive windows as desired. If the DSP320 determines that the response signal is a valid EAS tag signal, the DSP320 may begin deactivation or indicate detection of an EAS tag, depending on the particular mode of operation. When an EAS tag is detected, the electronic circuit 300 of the boot deactivator 104 indicates this detected status of the EAS tag 108 by activating an EAS tag status indicator, such as by illuminating the LED328 or causing the speaker 330 to produce an audible tone (step S510), at step S508. During periods when the electronic circuit 300 is not transmitting signals to the tag 108 or receiving signals from the tag 108, the electronic circuit 300 may be charged or recharged via the storage super capacitor 308 or, optionally, via the battery 310 (step S512). It is noted that although charging/recharging is shown at step S512, it is understood that charging can occur at any idle point of the tag detection cycle.

The present invention advantageously provides and defines a portable circuit, apparatus and method for detecting a tag attached to an article, deactivating the detected tag and generating an indication of the status of the tag in an electronic article surveillance system.

Embodiments of the invention can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both hardware and software elements. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Moreover, it should be noted that, unless stated to the contrary above, all of the accompanying drawings are not to scale. Many modifications and variations are possible in light of the above teaching without departing from the scope and spirit of the invention, which is limited only by the following claims.

Claims (12)

1. An electronic circuit for an Electronic Article Surveillance (EAS) device, the electronic circuit comprising:

a coil that induces a current when subjected to an electromagnetic field, and that also transmits an interrogation signal for energizing an EAS tag;

a tuning capacitor in electrical communication with the coil, the tuning capacitor and the coil establishing resonance to transmit the interrogation signal;

a storage capacitor in electrical communication with the coil, the storage capacitor receiving induced current from the coil;

a receiver that receives a response signal from an excited EAS tag; and

a processor in communication with the receiver and powered by the storage capacitor, the processor processing a response signal received from the receiver to determine if the response signal is valid and ready for deactivation, and if so, transmitting a deactivation signal to the EAS tag, and wherein the electronic circuit generates a tag status indication when the response signal is valid.

2. The electronic circuit of claim 1, further comprising a first diode in electrical communication with the coil and the storage capacitor, the first diode rectifying an induced current from the coil.

3. The electronic circuit of claim 2, further comprising a voltage divider in electrical communication with the storage capacitor and the first diode, the voltage divider providing a processor voltage.

4. The electronic circuit of claim 3, further comprising a linear voltage regulator in electrical communication with the voltage divider, the linear regulator regulating the processor voltage.

5. The electronic circuit of claim 1, wherein the processor analyzes the response signal to determine an EAS tag status.

6. The electronic circuit of claim 2, wherein the processor generates a transmit enable control signal that controls operation of the first diode to inhibit reception of the induced current by the storage capacitor when the coil transmits the interrogation signal.

7. An apparatus for detecting and deactivating an Electronic Article Surveillance (EAS) tag, the apparatus comprising:

a housing securable to at least one of a barcode scanner and an RFID scanner;

an electronic circuit located within the housing; and

at least one user observable indicator controlled by the electronic circuit, the at least one user observable indicator being secured to the housing and providing a tag deactivation status,

the electronic circuit includes:

a coil that induces a current when subjected to an electromagnetic field, and that also transmits an interrogation signal for energizing an EAS tag;

a tuning capacitor in electrical communication with the coil, the tuning capacitor and the coil establishing resonance to transmit the interrogation signal;

a storage capacitor in electrical communication with the coil, the storage capacitor receiving induced current from the coil;

a receiver that receives a response signal from an excited EAS tag; and

a processor in communication with the receiver and powered by the storage capacitor, wherein the processor processes a response signal received from the receiver to determine if the response signal is valid and ready to deactivate, and if so, transmits a deactivation signal to the EAS tag, and wherein the electronic circuit generates a tag status indication when the response signal is valid.

8. The apparatus of claim 7, wherein the electronic circuit further comprises a first diode in electrical communication with the coil and the storage capacitor, the first diode rectifying induced current from the coil.

9. The apparatus of claim 8, wherein the electronic circuit further comprises a voltage divider in electrical communication with the storage capacitor and the first diode, the voltage divider providing a processor voltage.

10. The apparatus of claim 9, wherein the electronic circuit further comprises a linear voltage regulator in electrical communication with the voltage divider, the linear regulator regulating the processor voltage.

11. The apparatus of claim 7, wherein the processor analyzes the response signal to determine an EAS tag deactivation status.

12. The apparatus of claim 7, wherein the at least one user observable indicator is a Light Emitting Diode (LED) that provides a visual indication of the tag status.