Patent Grant
8138921
The present invention generally relates to the field of electronic security and dual use tags (e.g., EAS, RFID, etc.) and devices. More specifically, embodiments of the present invention pertain to methods for deactivating a security/dual use tag and apparatuses for the same.
Aspects of the present invention relate to a method of deactivating security/dual use tags, a security/dual use tag deactivation apparatus, and variations thereof. The methods and apparatuses described in the present invention enable the reliable deactivation of the tags (e.g., electronic article surveillance (EAS)) so that the tags are completely deactivated and do not reactivate (e.g., the Lazarus effect). In one embodiment, this invention modifies conventional (EAS) tag readers, and more specifically, deactivation pads associated with such readers, to include read electronics (e.g., circuitry configured to read a tag within a certain range of the pad). Such a modification can be utilized in various ways, some of which are explicitly described below with regard to the method of the present invention.
According to the general method of the present invention, a security/dual use tag may be deactivated by placing the tag a first distance from a deactivation apparatus and determining whether a deactivation confirmation signal has occurred. The deactivation confirmation signal will occur if the tag is within a sufficient deactivation distance of the deactivation apparatus. If the deactivation confirmation signal did not occur, the tag is then moved closer to the deactivation apparatus to ensure that the tag is deactivated. In exemplary embodiments, the first distance is within a specified deactivation field of the deactivation apparatus.
In other embodiments, it may be beneficial to read the tag before determining whether the deactivation confirmation signal has occurred. In addition, it may also be beneficial to determine the distance from the pad to the tag (i.e., the “pad-to-tag” distance) based on a coupling coefficient measured with the tag. In embodiments that determine the pad-to-tag distance, the confirmation signal may be generated when the pad-to-tag distance is sufficiently close to deactivate the tag. Additionally or alternatively, a warning signal may be generated when the pad-to-tag distance is not sufficiently close to deactivate the tag.
In another aspect, the present invention concerns a security tag deactivation apparatus. In general the deactivation apparatus comprises a pad configured to transmit a deactivation pulse having a power sufficient to deactivate the security tag when the security tag is within a deactivation field of the deactivation apparatus. The deactivation pulse transmitted may be a radio frequency, high frequency, very high frequency, or ultra high frequency pulse or signal. The apparatus also includes a tag reader configured to detect a signal transmission from an active tag when the active tag is within a read field of the deactivation apparatus, a confirmation indicator configured to indicate that the pad has sent the deactivation pulse, and logic configured to determine when the security tag is within the deactivation field, determine when the tag is active in the read field, and communicate to the confirmation indicator that the pad has sent the deactivation pulse. Preferably, the read field has a greater volume than the deactivation field.
In various embodiments of the deactivation apparatus, the reader may be configured to attempt to detect a signal transmission before the confirmation indicator indicates that the deactivation pad has sent a deactivation pulse. In other embodiments, the reader may be configured to determine the distance from the pad to the tag (i.e., the “pad-to-tag” distance). In such embodiments, the confirmation indicator may be configured to generate a confirmation signal when the pad-to-tag distance is sufficiently close to deactivate the tag. In other variations, the deactivation pulse has sufficient power to form a short circuit between two conductive plates or members across a dielectric in the security tag. In such embodiments, the dielectric may be an organic dielectric or an inorganic dielectric. Furthermore, the dielectric may have a breakdown voltage and the deactivation pulse may have a power sufficient to generate an electric potential greater than the breakdown voltage, across the dielectric when the security tag is with the deactivation field.
The present invention provides a security/dual use tag deactivation apparatus and methods for reliably deactivating a security/dual use tag by modifying a deactivation pad to include circuitry configured to read the tags within a certain range of a deactivation pad. Using read circuitry that is able to estimate a coupling coefficient between the security tag and the deactivation pad, an attempt to deactivate a tag before the tag is close enough to the pad to achieve reliable deactivation may be avoided, and it is possible to subsequently verify that the pad has completely and actually deactivated the tag before it is taken away from the deactivation apparatus.
These and other advantages of the present invention will become readily apparent from the detailed description of preferred embodiments below.
Reference will now be made in detail to preferred embodiments of the invention. While the invention will be described in conjunction with the following preferred embodiments, it will be understood that the description is not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents that may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be readily apparent to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present invention.
For the sake of convenience and simplicity, the terms “coupled to,” “connected to,” and “in communication with” mean direct or indirect coupling, connection or communication unless the context indicates otherwise. These terms are generally used interchangeably herein, but are generally given their art-recognized meanings. Also, for convenience and simplicity, the terms “surveillance,” “EAS,” and “security” may be used interchangeably with respect to intended uses and/or functions of a device and/or tag, and the terms “EAS,” “dual use,” “surveillance,” and “security” when referring to a tag or device may be used herein to refer to any tag and/or device having an EAS function. Furthermore, there are many possible variations of the process flows and apparatuses described herein. Accordingly, it should be understood that the possible permutations and combinations described herein are not meant to limit the invention. Specifically, variations that are not inconsistent may be mixed and matched as desired.
Aspects of the present invention concern methods for deactivating security tags, and security tag deactivation apparatuses for accomplishing the same. The general method for deactivating security tags comprises (a) placing the security tag a first distance from a deactivation apparatus; (b) determining whether a deactivation confirmation signal has occurred; and (c) when the deactivation confirmation signal has been determined not to have occurred, placing the security tag closer to the deactivation apparatus than the first distance.
In some variations of the general method, the tag is read before determining if the deactivation confirmation signal occurred. In other variations, the method further comprises reading the security tag to determine the pad-to-tag distance based on a coupling coefficient measured with the tag. The pad-to-tag distance can be used to subsequently cause a deactivation pad in the deactivation apparatus to take action or not to take action. For example, if the pad-to-tag distance is determined to be insufficiently close to deactivate the tag, then the deactivation pad will not transmit a deactivation pulse to deactivate the tag. On the other hand, if the pad-to-tag distance is sufficiently close to deactivate the tag, the deactivation pad will transmit a deactivation pulse.
A further aspect of the present invention concerns a security tag deactivation apparatus, comprising (a) a pad configured to transmit a deactivation pulse having a power sufficient to deactivate a security tag when the security tag is within a deactivation field of the deactivation apparatus; (b) a tag reader configured to detect a signal transmission from an active tag when the active tag is within a read field of the deactivation apparatus, the read field having a greater volume than the deactivation field; (c) a confirmation indicator configured to indicate that the pad has sent the deactivation pulse; and (d) logic configured to determine when the security tag is within the deactivation field, determine when an active tag is in the read field, and communicate to the confirmation indicator that the pad has sent the deactivation pulse.
In some embodiments, the reader may be configured to attempt to detect a signal from the tag before the confirmation indicator indicates that the pad has sent the deactivation pulse. Alternatively or additionally, the reader may be configured to determine the distance from the pad to the tag (i.e., the “pad-to-tag” distance). In such embodiments, the tag may be deactivated (or not deactivated) by the deactivation pad depending on the pad-to-tag distance as determined by the read circuitry in the deactivation apparatus.
The invention, in its various aspects, will be explained in greater detail below with regard to exemplary embodiments.
Exemplary Methods of Deactivating a Security Tag
A first aspect of the present invention relates to methods of deactivating a security tag (e.g., an EAS tag or dual use EAS/RFID tag, etc.). Dual use (e.g., multi-mode) tags and methods of making and using such tags are described in U.S. Pat. No. 7,286,053, issued Oct. 23, 2007 and U.S. patent application Ser. No. 11/870,775, filed Oct. 11, 2007, the relevant portions of which are incorporated herein by reference. As illustrated in the process flow shown in
Specifically, the deactivation confirmation signal occurs when the tag is sufficiently close to (e.g., within a deactivation distance of) a deactivation pad within the deactivation apparatus, and a deactivation pulse has been sent/transmitted. For example, if read circuitry in the apparatus determines that the tag is within the deactivation distance (e.g., the deactivation field of the deactivation pad), the pad then transmits a deactivation pulse. The pulse generally has power sufficient to deactivate the security tag when the tag is within the deactivation field of the deactivation apparatus. When a tag is successfully deactivated, as indicated in step 125 (e.g., the tag is within the deactivation field and a pulse is transmitted), the deactivation confirmation signal occurs. However, if the deactivation confirmation signal does not occur, then the apparatus has determined that the tag does not meet the conditions for successful deactivation, and the security tag should be placed closer to the deactivation apparatus (see step 130). Optionally, a confirmation indication and/or warning signal may be sent to a user to indicate that the tag has or has not been deactivated, as described herein with regard to
Typically, the first distance should be (or is) within a specified or predetermined deactivation field of the deactivation apparatus. Although there is no specific standard for the parameters that define the deactivation field, the deactivation field or distance is generally defined by the breakdown voltage of the capacitor dielectric on the tag, or the pulse density of the deactivation pulse transmitted by the pad. In the alternative, if tag deactivation is accomplished by another method (e.g., programming an EEPROM bit, etc.), then the deactivation distance depends on parameters relating to the method chosen to deactivate the tag.
In some implementations, a reader may read the security tag(s) before determining whether the deactivation confirmation signal has occurred. In these implementations, the first distance should be sufficient to read and/or detect the tag. Although there is no specific standard with regard to the parameters defining the read and/or detection field, in general, the read distance is determined by the output power of the reader and the minimum amount of power for the tag to operate (e.g., absorb and backscatter the signal transmitted by the reader). The minimum amount of power is dependent upon factors that may include the size and geometry of the reader antenna (e.g., a larger antenna diameter provides a longer read range), the size and geometry of the tag antenna, the tag antenna quality factor, the tag-to-reader orientation, and the presence of absorbers (e.g., metals) in the vicinity of the tag and reader.
An exemplary process flow 200 illustrating this variation is provided in
In some embodiments, the deactivation pulse may be transmitted from the deactivation apparatus when the pad-to-tag distance is sufficiently close to deactivate the tag. Alternatively or additionally, the deactivation apparatus/pad will not transmit the deactivation pulse if it is determined that the pad-to-tag distance is not sufficiently close to deactivate the tag.
Further variations of this embodiment include sending confirmation indications and/or warning signals to a user, indicating that the tag has or has not been deactivated. The process flow 400 of
In further embodiments, the reader may read a tag (and/or tag population) within a read field after transmitting the deactivation pulse, to determine if there are any (remaining) active tags within the deactivation field. Preferably, in such embodiments, the read field volume is from 2 to 10 (e.g., 2 to 4) times that of the deactivation field. In many instances, the read field volume may be defined by a distance from the pad in which the tag can be detected. An exemplary process flow 500 according to this embodiment is shown in
Additionally, in many of the above-described variations, a warning signal may also be generated if the pad-to-tag distance is not sufficiently close to deactivate the tag. Similarly, it is also possible to generate a confirmation indication when the pad-to-tag distance is sufficiently close to deactivate the tag prior to deactivating the tag. Such warning signals and/or confirmation indications may include visual and/or audible confirmation (e.g., a red light and/or a buzzer as a warning indicator; a green light and/or a bell as a confirmation indicator). However, the warning signals and/or confirmation indications are not limited to only visual and/or audible indicators. For example, the warning signals/confirmation indications may be displayed on a computer for the user, and/or include any other type of sensory feedback, such as tactile indicators (e.g., a silent vibrating device) or olfactory indicators (e.g., release of a pleasant scent). In exemplary embodiments, the confirmation indication and/or warning signal is generated within a predetermined period of time. The time between deactivation confirmation and generation of the confirmation indication (or warning signal if deactivation failed) is relatively short. Response times are preferably less than a second (e.g., milliseconds) and response times in the range of tens of seconds are too long.
An exemplary process flow 600 according to a further embodiment of the present method is shown in
On the other hand, if the deactivation apparatus sends the deactivation pulse to the tag (see step 660), a reader subsequently reads the tag (see step 665) to determine if there are any active tags remaining within the read field (see question box 670). In general, the read field should be 2 to 4 times the volume of the deactivation field, so that tags within a distance from the pad and/or reader that can be detected, but were not deactivated, can be recognized. This can be accomplished by determining whether a coupling signal was transmitted by the tag and received by the reader (question box 670). Once such tags are recognized, a warning signal may be sent to the user (see step 645) indicating that at least one active tag is within the read field (i.e., close to the deactivation pad), and has not deactivated. The user then places the tag (and an article upon or in which the tag may be affixed) closer to the deactivation pad (see step 650), and the cycle (steps 620, 630, 640, 645, and 650) repeats to ensure that the tag is deactivated. In the alternative, a confirmation indication may optionally be sent to the user (see step 680) if the reader did not receive a coupling signal from the tag(s) in the read field, which indicates that the tag has been deactivated (see step 690).
In some embodiments, the tag may be deactivated by forming a short circuit between two conductive plates or members across a dielectric. In such embodiments, the dielectric may be an organic or an inorganic dielectric. The organic dielectric may comprise polyimide, poly(benzocyclobutene) [BCB], or SiLK® dielectric material (SiLK is a registered trademark of Dow Chemical Co., Midland, Mich.). Possible inorganic materials may comprise aluminum oxide, silicon dioxide [which may be conventionally doped and/or which may comprise a spin-on-glass], silicon nitride, silicon oxynitride, or a combination thereof as a mixture or a multilayer structure, silicates, silicones, sesquioxanes, tetraalkoxysilanes, trialkoxyaluminum compounds, titanium tetraalkoxides, and/or nanoparticles of silica, alumina, ceria, titania, zirconia, etc. The dielectric used in these variations may have a breakdown voltage of, e.g., at least 2 V, 5 V, 10 V, 15 V, 20 V, or any minimum value greater than 2 V, up to a maximum of 25 V, 30 V, 40 V or other value greater than the minimum value. The short circuit between the conductive plates or members may be formed by applying an electric potential greater than the breakdown voltage across the dielectric. In various embodiments, the electric potential may be generated by the tag from a radio frequency, high frequency, very high frequency, or ultra high frequency signal from the deactivation apparatus.
Exemplary Security Tag Deactivation Apparatuses
A second aspect of the present invention concerns a security tag deactivation apparatus. Generally, the apparatus comprises a pad configured to transmit a deactivation pulse having a power sufficient to deactivate the security tag when the tag is within a deactivation field of the deactivation apparatus. The apparatus also comprises a tag reader configured to detect a signal transmission from an active tag when the active tag is within a read field of the deactivation apparatus. The tag reader may also be configured to detect a transmitted signal from a tag and/or comprise logic for generating confirmation and warning indicator signals. Typically, the read field has a greater volume than the deactivation field. The apparatus may further include one or more confirmation indicators configured to indicate that the pad has or has not sent the deactivation pulse. In addition, the apparatus comprises logic to determine when the security tag is within the deactivation field, determine when an active tag is in the read field, and communicate the deactivation confirmation signal. The logic communicates with the other elements of the apparatus, and triangulates their activities accordingly.
The deactivation pulse transmitted by the pad may be a radio frequency, high frequency, very high frequency, or ultra high frequency signal. In some variations, the deactivation pulse has a power sufficient to form a short circuit between two conductive plates or members across a dielectric in the security tag. In such embodiments, the dielectric may comprise an organic dielectric (e.g., polyimide, poly(benzocyclobutene) [BCB], etc.) or an inorganic dielectric (e.g., aluminum oxide, silicon dioxide [which may be conventionally doped and/or which may comprise a spin-on-glass], silicon nitride, silicon oxynitride, silicates, silicones, sesquioxanes, aluminumates, titanates nanoparticles of silica, alumina, ceria, titania, zirconia, or a combination thereof as a mixture or a multilayer structure). In some variations, the dielectric has a breakdown voltage, and the deactivation pulse has a power sufficient to generate an electric potential greater than the breakdown voltage across the dielectric when the security tag is within the deactivation field.
In some embodiments, the tag reader may be configured to attempt to detect a signal from the tag before the confirmation indicator indicates that the pad has sent the deactivation pulse. In such a case, the reader may include circuitry configured to determine or estimate a coupling coefficient and/or distance between the tag and the deactivation apparatus. As previously discussed, the reader generally does not measure the specific value of the coupling coefficient, and instead estimates the loading imposed by the tag (e.g., power absorbed by the tag) by measuring the power drawn from the reader antenna. Generally, the coupling coefficient is in the range of a few percent (e.g., 1-20%).
Alternatively or additionally, the tag reader may be configured to determine the distance from the pad to the tag (i.e., the pad-to-tag distance). The pad-to-tag distance may be determined from a read signal coupling between the pad and the tag. In such embodiments, the confirmation indicator may be configured not to indicate that the deactivation pulse has been sent when the pad-to-tag distance is not sufficiently close to deactivate the tag. In other variations, the pad may be configured to send a deactivation pulse if the logic determines that the pad-to-tag distance is sufficiently close to ensure delivery of sufficiently high pulse power to deactivate the tag. In these variations, the confirmation indicator may indicate that the deactivation pulse has been sent after the pad sends the deactivation signal.
In one embodiment, the confirmation indicator is configured to generate a confirmation indication when the pad-to-tag distance is sufficiently close to deactivate the tag. The confirmation indication may comprise any type of sensory feedback to the user, and which may include, for example, a visual signal such as a light (e.g., red for warning and/or green for confirmation), an audible signal (e.g., a buzzer for warning and/or a bell for confirmation), a tactile signal (e.g., a vibrating device, such as those commonly found in cellular phones and/or pagers for warning or confirmation), and/or an olfactory signal (such as a pleasant, sweet or flower-like scent, released as a confirmation indication). In exemplary embodiments, the confirmation indication is generated within a predetermined period of time, preferably no more than 1 second (e.g., less than 100 milliseconds).
In another implementation, the tag reader may be configured to attempt to detect the signal transmission before the pad sends the deactivation pulse. In this implementation, the confirmation indicator may be configured to generate a confirmation indication when the reader and/or logic determine that there are no active tags in a predetermined read field. Alternatively or additionally, the deactivation apparatus and/or the confirmation indicator may further comprise a warning indicator mechanism configured to indicate when the deactivation apparatus determines that there is an active tag in the read field. As with the confirmation indication, the warning signal may comprise any sensory feedback as described herein, and is generated within milliseconds of determining that deactivation failed.
Optionally, the tag reader may also be configured to determine whether there are active tags in the read field by broadcasting a wireless transmission at an appropriate frequency and strength. The reader may then determine whether a reply is received. In various implementations, the read field has a volume of at least 1.5 times that of the deactivation field volume. In exemplary implementations, the read field volume is from 2 to 10 (e.g., 2 to 4) times that of the deactivation field. In general, the read field volume can be defined by a distance from the pad in which the tag can be detected.
Specifically, the logic is configured to receive inputs from the read and deactivation pad, and make determinations and/or decisions based on the inputs received (e.g., whether a tag has been read, and if so how many times (once, twice, etc.); whether power was absorbed when the tag was read, and if so, how much power was absorbed; whether a deactivation pulse was sent, etc.). Furthermore, the logic can be configured to provide confirmation indications and/or warning signals based on the inputs received from the reader and the deactivation pad, or if other specified conditions have been met. For example, the logic can provide a confirmation signal instructing the deactivation pad to send the deactivation pulse if the tag is close enough to the pad for successful deactivation, or in the alternative, it can provide a warning signal instructing the deactivation pad to block the deactivation pulse if the tag-to-tag distance is insufficient. Similarly, the logic can determine if an active tag is present in the read field after the deactivation pulse has been sent, and send a warning signal to the user alerting the user that at least one tag failed to properly deactivate. The logic may also generate a confirmation indication to notify a user that a tag was properly deactivated (e.g., green light 786) or that the tag is within the deactivation distance from the pad (e.g., yellow light 784). Also, the logic can generate a warning signal (e.g., red light 782) to alert the user that a tag has not been properly deactivated.
The capabilities of the logic circuitry are not limited to the examples described herein, and may include any relevant action that is capable of being controlled by a computer. Furthermore, any action managed or controlled by the logic circuitry may also be done using computer software. It is within the ability of one skilled in the art to design and implement such logic.
Portions of the detailed descriptions herein have been presented in terms of processes, procedures, logic, function(s), and/or other representations of operations within a computer, signal processor, controller, sensor and/or memory. These descriptions and representations are generally used by those skilled in the data processing arts to convey the substance of their work to others skilled in the art. A process, procedure, logic block, function, operation, etc., is herein, and is generally, considered to be a self-consistent sequence of steps or instructions leading to a desired and/or expected result. The steps generally include physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical, magnetic, optical, or quantum signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer and/or signal/data processing system.
It should be borne in mind, however, that all of these and similar terms are associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise and/or as may be apparent from the following discussions, it is appreciated that throughout the present application, discussions utilizing terms such as “processing,” “determining,” “displaying” or the like, refer to the action and processes of a computer or data processing system, or similar processing device (e.g., an electrical, optical, or quantum computing or processing device), that manipulates and transforms data represented as physical (e.g., electronic) quantities. The terms refer to actions, operations and/or processes of the processing devices that manipulate or transform physical quantities within the component(s) of a system or architecture (e.g., registers, memories, sensors, other such information storage, transmission or display devices, etc.) into other data similarly represented as physical quantities within other components of the same or a different system or architecture.
Although the description herein focuses on methods and hardware (e.g., architectures, systems and/or circuits), the present invention also includes a computer program and/or software, implementable and/or executable in a general purpose computer or workstation equipped with conventional digital and/or analog signal processor(s), configured to perform one or more steps of the method and/or one or more operations of the hardware. Thus, a further aspect of the invention relates to software that implements the above method(s) and/or algorithm(s). For example, the invention may further relate to a computer program, computer-readable medium containing a set of instructions which, when executed by an appropriate signal processing device, is configured to perform the methods described herein. For example, the computer-readable medium may comprise any medium that can be read by a signal processing device configured to read the medium and execute code stored thereon or therein, such as a floppy disk, CD-ROM, magnetic tape or hard disk drive. Such code may comprise object code, source code and/or binary code.
The code is generally configured for transmission through an appropriate medium, such as copper wire, a conventional network cable, a conventional optical data transmission cable, or even air or a vacuum (e.g., outer space) for wireless signal transmissions. The code is generally digital, and is generally configured for processing by a conventional digital data processor (e.g., a microprocessor, microcontroller, or logic circuit such as a programmable gate array, programmable logic circuit/device or application-specific [integrated] circuit).
As further illustrated in
The tag reader 750 generally includes a signal transmitter 760 that transmits a RF, HF, VHF, or UHF signal and/or a signal detector 770 configured to detect a backscattered or reflected signal from the tag 790. The tag reader 750 and/or the various components of the tag reader may also include one or more antennas (e.g., 765 and 775) configured for wireless transmission and/or reception of signals between the reader and the tag. In one embodiment, a single antenna can be configured for both transmission and reception functions.
The logic 710 of the apparatus 700 is configured to generate a confirmation or warning signal to be transmitted to the confirmation indicator if a tag was properly deactivated and/or if the tag failed to deactivate. The warning and/or confirmation indication may be a tactile signal, such as a silent vibrating device. For example, the tactile signal may be generated by a pager attached to a belt that is worn by a user 788. The pager can transmit a silent vibration to confirm that the tag has been properly deactivated or warn the user that the tag has not been properly deactivated. Alternatively or additionally, the confirmation indication/warning signal may comprise visual, auditory, and/or olfactory signals perceived by the user. For example, a set of warning and/or confirmation lights 780 may alert the user that a tag has been deactivated (e.g., green light 786), that a tag has not been deactivated (e.g., red light 782), or that a tag is within the deactivation distance from the pad (e.g., yellow light 784). In the alternative, auditory signals may be used as a warning signal or confirmation indication. For example, a single bell tone may indicate that a tag is within the deactivation field, two bell tones may indicate that a deactivation pulse was sent (the tag has been deactivated) and/or that there are no active tags found during the second tag reading process, and a buzzer may indicate that the tag is not within the deactivation field or that an active tag has been located in the read field during the second read process.
Thus, the present invention provides methods of deactivating a security/dual use tag and apparatuses for the same. Modifying the deactivation apparatus to include circuitry to read a security tag within a certain range of the pad, results in reliable and complete deactivation of the tag such that it does not reactivate (e.g., the “Lazarus effect”). After the read circuitry in the deactivation apparatus reads the security tag, logic in the apparatus estimates the distance between the tag and the pad, and determines when the distance is sufficiently close to deactivate the tag. If the tag is close enough to ensure high power delivery of a deactivation pulse, the pad sends the deactivation pulse. If the tag is not sufficiently close, the deactivation pulse is not sent. A sensory confirmation indication can alert a user that deactivation has occurred. In the alternative, a different sensory warning signal can alert a user if the deactivation has not occurred, so that the tag can be moved closer to the pad for deactivation. Additionally or alternatively, after the deactivation pulse from the pad is complete, a reader may read the tag (or group of tags) to ensure that there are no active tags in the read field. Confirmation indicators and/or warning signals may be subsequently sent to the user to indicate whether or not active tags remain in the deactivation field after the deactivation pulse has been sent.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.
This application claims the benefit of U.S. Provisional Application No. 60/964,287, filed Aug. 9, 2007, which is incorporated herein by reference in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3967161 | Lichtblau | Jun 1976 | A |
| 4498076 | Lichtblau | Feb 1985 | A |
| 4728938 | Kaltner | Mar 1988 | A |
| 5059951 | Kaltner | Oct 1991 | A |
| 5257010 | Rehder | Oct 1993 | A |
| 5640151 | Reis et al. | Jun 1997 | A |
| 6359562 | Rubin | Mar 2002 | B2 |
| 6857567 | Latimer et al. | Feb 2005 | B2 |
| 7132947 | Clifford et al. | Nov 2006 | B2 |
| 7495564 | Harold et al. | Feb 2009 | B2 |
| 7527198 | Salim et al. | May 2009 | B2 |
| 7642915 | Eckstein | Jan 2010 | B2 |
| 20070210922 | Clifford et al. | Sep 2007 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 60964287 | Aug 2007 | US |
