HK1114217B - An integrated eas/rfid device and disabling devices therefor - Google Patents

Description

Integrated EAS/RFID device and disabling device therefor

Cross Reference to Related Applications

This application claims priority from U.S. provisional patent application No. 60/630,351 entitled "decoupling Devices for an Integrated EAS/RPID Device," filed on 2004, 11/23/2004, 35u.s.c. § 119, which is hereby incorporated by reference in its entirety.

Technical Field

The present invention relates to integrated Electronic Article Surveillance (EAS) and Radio Frequency Identification (RFID) devices capable of implementing dual EAS/RPID functionality, and more particularly to devices that can be reactivated to restore EAS and RFID functional performance.

Background

In general, many devices designed to perform only EAS functions (i.e., to "activate" or "deactivate" merchandise) are known to be capable of being reactivated. For example, the magnetic treatment to deactivate EAS markers provides a simple deactivation method by magnetization and demagnetization of the magnetic bias strip. Because the magnetization process is reversible, reactivation is possible in this type of device. However, in the case of EAS markers such as RFLC (radio frequency induced capacitor) resonant markers that are deactivated by radio frequency waves typically in the range of about 8.2MHz (+ -10%), the induced high voltage may damage the insulation layer at the weak point, creating a short circuit. This is a destructive process and typically cannot be reactivated.

With the advent of RFID technology, many retailers are considering tagging goods (e.g., per item, per box, per shelf) with RFID tags. Meanwhile, Electronic Article Surveillance (EAS) technology and equipment have proven important to reduce theft and so-called "merchandise loss". It is envisioned that the RFID device may also provide many of the same advantages known from EAS technology, with additional advantages or capabilities such as inventory control, shelf reading, non-line-of-sight reading, and the like. However, there are several problems associated with previously known combination EAS and RFID devices or tags or labels. These problems include the following:

cost-because two devices and two separate readers or deactivators are typically required, a combination EAS/RFID tag or label is generally more expensive for the retailer/manufacturer.

The size-the size of the composite structure is generally larger.

Interference-interference can occur if devices overlap, resulting in reduced performance of one or both of the EAS and RFID functions unless specific design features are provided to reduce interference caused by the overlap.

These problems associated with cost, size and performance degradation and interference caused by overlap are solved and overcome in commonly owned U.S. provisional patent application No. 60/628,303 entitled "comboeeas/RFID LABEL OR TAG," filed on year 11/15 2004, PCT application No. [ attorney docket No. f-TP-00023US/WO ], filed on day 11/15 2005, and entitled "COMBINATION EAS AND RFID LABEL OR TAG," which is hereby incorporated by reference in its entirety. However, there is no solution to the problem of reactivating the EAS function of the EAS/RFID tag after deactivation, as opposed to an integrated EAS/RFID tag. Accordingly, there is a need to design an integrated EAS/RFID tag that is economical and solves many of the above-mentioned problems.

Disclosure of Invention

It is an object of the present invention to provide an integrated EAS/RFID device that maintains its state even when power is removed.

More particularly, the present disclosure relates to the use of semiconductors with Electronic Article Surveillance (EAS) and Radio Frequency Identification (RFID) tags. The semiconductor includes a current receiving portion coupled to the antenna and configured to communicate with at least one other portion of the semiconductor such that upon receiving and forwarding energy and signals from the antenna, a plurality of functions can be performed by the at least one other portion of the semiconductor. The semiconductor further comprises at least one of the following switches: a first switch operatively coupled to the current receiving portion such that the plurality of functions are disabled after the first switch is turned off; and a second switch operatively coupled to the current receiving portion such that at least one of the plurality of functions is at least partially disabled after the second switch is turned off. At least one of the first switch and the second switch includes a preset memory, and the preset memory sets a conductive state of at least one of the first switch and the second switch. The conductive state may be set during active operation of the semiconductor and may be maintained by a power controller having a storage device for storing the conductive state when the device is in a powered down state. The power controller may modulate at least one of the first switch and the second switch.

The current receiving portion may be a rectifying front end portion including a source electrode, a drain electrode, a modulating impedance, and a first diode, both operatively coupled to the source electrode and the drain electrode to form a parallel resonant inductor-capacitor (LC) circuit; and a second diode operatively coupled to the drain electrode such that the LC circuit forms a rectifying circuit. The semiconductor may comprise an antenna electromagnetically coupled to the semiconductor and designed to receive and forward energy and signals from and to the current receiving portion.

The present disclosure also relates to an integrated Electronic Article Surveillance (EAS) and Radio Frequency Identification (RFID) tag comprising an antenna, a semiconductor adapted to be coupled to the antenna and configured to receive and transmit energy and signals to the antenna, the semiconductor comprising a current receiving end portion arranged in the semiconductor and configured to communicate with at least one other portion of the semiconductor such that upon receiving and forwarding energy and signals from and to the antenna, a plurality of functions can be performed by the at least one other portion. The semiconductor includes at least one of the following switches: a first switch operatively coupled to the current receiving portion such that the plurality of functions are disabled after the first switch is turned off; and a second switch operatively coupled to the current receiving portion such that at least one of the plurality of functions is at least partially disabled after the second switch is turned off.

Drawings

The subject matter regarded as the embodiments is particularly pointed out and distinctly claimed in the concluding portion of the specification. The organization and method of operation of the embodiments, however, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings.

FIG. 1 is a schematic diagram of an integrated EAS/RFID device in accordance with the present disclosure;

FIG. 2A is a circuit schematic diagram of one embodiment of the integrated EAS/RFID device of FIG. 1 for high frequency operation;

FIG. 2B is a circuit schematic diagram of one embodiment of the integrated EAS/RFID device of FIG. 1 for radio frequency operation; and

fig. 3 is a schematic diagram of a floating gate/buried gate device for controlling channel resistance.

Detailed Description

Especially for the EAS function of the device, integrated EAS/RFID devices typically do not provide full functionality without a suitable deactivation method. (the EAS marker or marker is often referred to as a one-bit transponder because it contains only one piece of information-whether the marker is activated or deactivated.) the integrated EAS/RFID device of the present disclosure is capable of implementing a dual EAS/RFID function, i.e., the RFID function provides extensive information about the marked item and the attached EAS function provides limited information about the item (activation/deactivation).

Generally, the detection range of the EAS function is greater than the detection range of the RFID function. An attractive feature of such an integrated device is that the EAS deactivation function may be provided based on a complex code preset in the RFID device. Once verified, the RFID portion of the integrated device generates an electrical pulse to change the state of the integrated device, resulting in deactivation of the EAS and/or RFID device functions. The present disclosure describes a device that is capable of changing or retaining its impedance state even when powered down.

In addition, the new approach to deactivation of the EAS portion or the EAS/RFID portion described herein allows for the retention of any data stored in the RFID portion of the integrated EAS/RFID device. In this way, significant savings are achieved by using a tag that performs a dual function. RFID functions are used for logical operations such as manufacturing process control, merchandise transport, inventory, item check-up, return, etc. An EAS function is performed at the exit for theft prevention purposes.

Basically, at least one switch and a preset memory enabling the execution of a one-bit EAS function are introduced to a portion of the RFID circuit. The conductive state of the switch (e.g., on/off, low/high resistance) may be set during the active (power-up) of the device and maintained while the device is in the power-down state.

Numerous specific details may be set forth herein to provide a thorough understanding of embodiments of the invention. However, it will be understood by those skilled in the art that the various embodiments of the 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 obscure the various embodiments of the invention. It can be appreciated that the specific structural and functional details described herein may be representative and do not necessarily limit the scope of the invention.

It is worthy to note that any reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

Some embodiments may be described using the expression "coupled" and "connected" along with their derivatives. For example, some embodiments may use the term "connected" to indicate that two or more elements are in direct physical or electrical contact with each other. In another example, some embodiments may be described using the term "coupled" to indicate that two or more elements are in direct physical or electrical contact. The term "coupled," however, also means that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments are not limited in this respect.

Referring now in detail to the drawings, wherein like parts may be designated by like reference numerals throughout the several views as shown in FIG. 1, the components of the passive integrated EAS/RFID tag or label 100 of the present invention include an antenna 110, which is an energy coupling device configured to receive energy and signals 120 from a smart semiconductor device 130 and to forward the energy and signals 120 to the smart semiconductor device 130. The antenna 110 may be used to receive and forward energy and signals associated with the tag or label 100. The antenna 110 may be a dipole antenna for Ultra High Frequency (UHF) applications and may be a loop antenna for Radio Frequency (RF) applications. The embodiments are not limited in this respect. The semiconductor 130 is designed to perform analysis and calculation functions, which will be explained in more detail below with respect to fig. 2. The antenna 110 is operatively coupled to the semiconductor device 130 via the signal 120 and functions as a transceiver for EAS and RFID functions. Although the antenna 110 is shown as being separate from the semiconductor device 130 in one embodiment, the antenna 110 may be formed on the semiconductor device 130 as an integrated unit. The embodiments are not limited in this respect.

Semiconductor device 130 includes built-in dual function circuitry for controlling EAS and RFID functions, respectively. The circuitry controlling the EAS/RFID functions may share the same (or the same portions of) circuitry or be coupled to a common component, such as antenna 110. As will be described later, in one particular embodiment, diodes commonly used for rectification (often non-linear) may be designed to perform certain EAS functions, such as mixing and harmonic generation. The reader may also be designed to cooperate with either (or both) of the EAS or RFID devices/functions. Such a reader is disclosed in commonly owned U.S. provisional patent application No. 60/629,571, entitled "INTEGRATED 13.56.56 MHz EAS/RFID DEVICE", filed on 18/2004, and PCT patent application No. [ attorney docket No. f-TP-00018US/WO ], entitled "EASREADER DETECTING EAS funcition FROM RFID DEVICE", filed concurrently herewith, both of which are hereby incorporated by reference in their entirety.

The semiconductor device 130 must be fully powered in order to perform the logic operations required for various RFID applications, such as access control, document tracking, livestock tracking, product authentication, retail tasks, and supply chain tasks. The primary function of an EAS device is to generate a unique signature in response to a system interrogation (preferably accomplished without fully activating the RFID logic function of a nearby RFID tag or label). As a result, the effective EAS read range is greater than the effective RFID read range, and EAS devices/functions tend to be more resilient to shielding and detuning effects.

It will be appreciated that it is important to deactivate or disable an EAS/RFID device once the item is purchased or the device has left the premises for reasons of privacy and/or interference with other EAS/RFID operating equipment in the store. In addition, there are situations where consumers who have purchased RFID tags prefer their personal information to remain confidential. To this end, RFID devices are well suited to set different security levels by establishing standard protocols, i.e., deactivation of the EAS function can be achieved by the capabilities of the RFID device.

Fig. 2A shows a specific example of an integrated EAS/RFID semiconductor device 130 having EAS function deactivation capability at a UHF band suitable for RFID applications in accordance with the present invention. The semiconductor device 130 is mounted on a substrate 210. The semiconductor device 130 includes a current receiving front-end section 220 that may also serve as a rectifying front-end section for the EAS/RFID semiconductor device 130. The front end portion 220 is typically coupled to the other or back end portion of the EAS/RFID semiconductor device 130, which performs multiple RFID functions, at nodes 1 and 2. The front end section 220 is coupled to the antenna 110 at terminals T1 and T2. Terminal T1 couples antenna 110 and source electrode 230, while terminal T2 couples antenna 110 and drain electrode 240. A variable or tunable impedance deltaz is coupled in parallel with electrodes 230 and 240 at nodes 3 and 4, respectively. Diode D1 is coupled in parallel with electrodes 230 and 240 at nodes 5 and 6, respectively. Similarly, a capacitance C1 is coupled in parallel with electrodes 230 and 240 at nodes 7 and 8, respectively. The source voltage Vss at node 7 and the drain voltage Vdd at node 8 provide a reserve energy through capacitor C1.

In one embodiment, the EAS portion 220 of the device mixes UHF (ultra high frequency) signals with Radio Frequency (RF) electric fields based on the non-linearity of the front end 220 of the integrated EAS/RFID device 130. More specifically, such embodiments are described in commonly owned, co-pending U.S. patent application No. 11/144,883, entitled "test liquid DETECTING RFID TAGS IN electric manufacturing system USING FREQUENCY MIXING," filed 3/6/2005, the entire contents of which are hereby incorporated by reference.

For deactivation of the EAS function, at least one switch S1 and S2 is inserted into the front end portion 220. Specifically, the switch S1 is located in the source electrode 230 between the terminal T1 and the node 3, and is coupled with the terminal T1 and the node 3. Therefore, because the switch S1 is located on the source electrode 230 upstream of the modulation impedance Δ Z, the diode D1, and the capacitor C1, the switch S1 controls the current flowing to the entire semiconductor device 130. In one embodiment, switch S2 is located between node 5 on source electrode 230 and diode D1 and is coupled to source electrode 230 and diode D1. Thus, switch S2 controls the current flowing through diode D1.

The switches S1 and S2 are designed to have certain basic characteristics, such as preset memory and programmable elements. The conductive state of the switch (e.g., on/off, low/high resistance) may be set during device active (power up) and maintained when the semiconductor device 130 is in a power down state. The programming functions are provided by the RFID back-end section 260 via the power controller 250, the power controller 250 including at least one state machine 250a (which is a switching device that performs logical operations), a memory 250b, a modulator 250c, and a demodulator 250 d. Modulator 250c is coupled to modulation impedance deltaz, switch S1, and switch S2. Drain electrode 240 is coupled to demodulator 250d at node 2. The state machine 250a determines the operating states of the switches S1 and S2 and the modulation impedance Δ Z and controls the switches S1 and S2 and the modulation impedance Δ Z. The operating state is stored in the memory 250 b. The state machine 250a also controls the switches S1 and S2 and the modulation impedance Δ Z through the modulator 250 c. Power controller 250 is typically supplied with energy through capacitor C1.

Once switch S2 is closed along with switch S1, the resistance is reduced sufficiently to maximize the sensitivity of EAS/RFID tag 100. Upon turning off switch S1 or S2, the resistance increases significantly, desensitizing the EAS function. In addition, the semiconductor 130 is designed such that the RFID device functions differently depending on which switch is turned off. For example, when the switch S1 is turned off, the RFID function 260 of the semiconductor device 130 is disabled because the switch S1 controls the current flowing from the terminal T1 to the source electrode 230. In contrast, because switch S2 only controls the current through diode D1, if S2 is turned off, only a reduction in the RFID performance or functionality of RFID function 260 occurs. The memory 250b may comprise, for example, a program memory, a data memory, or any combination thereof. The memory 250b may also include, for example, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), or combinations thereof, and so forth.

Fig. 2B shows a specific example of an integrated EAS/RFID semiconductor device having EAS function deactivation capability in the RF band range suitable for RFID applications in accordance with the present invention. More specifically, the semiconductor device 130 'is identical to the semiconductor device 130 except that the semiconductor device 130' is mounted on a substrate 210 'that also includes a current-receiving front-end section 220'. The difference between the front-end section 220' and the front-end section 220 of the semiconductor device 130 is that the switch S2 is no longer coupled in series with the diode D1 between nodes 5 and 6. Conversely, switch S2 is now coupled across terminals T1 and T2. In addition, a capacitor C2 is also coupled in series with switch S2 across terminals T1 and T2. The front-end section 220 'also serves as a rectifying front-end section for the EAS/RFID semiconductor device 130'. The capacitor C2 enables tuning or frequency matching of the resonant frequency of the front-end section 220' controlled by the modulation impedance az to the frequency of the interrogation signal 120 (see fig. 1).

Typically, a loss of power to the integrated marker 100 typically occurs when the merchandise is brought from a deactivation location to an exit point where an EAS system is located. The effectiveness of the EAS function deactivation is directly proportional to the value of the on/off resistance ratio RR of the switches S1 and S2, RR being determined by the switch resistance R in the off position_offSwitch resistance R divided by the on position_onIs defined, or RR ═ R_off/R_on。

One contemplated device that provides the performance of the switching function used as switches S1 and S2 is similar to a non-volatile flash memory device (or floating gate device), as shown in FIG. 3. More specifically, fig. 3 shows a schematic diagram of a floating gate/buried gate device 300 for controlling channel resistance. The device 300 may be designed as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) device that includes a substrate (or insulating layer) 310 in a coplanar orientation with a source electrode 320 and a drain electrode 330. The floating gate 340 is positioned between the control gate 350 and the source electrode 320 and the drain electrode 330 on the substrate 310. The device 300 is a MOSFET device having a floating gate 340. It is known that the conductivity characteristics of a field effect transistor channel depend on the amount of charge on the gate structure or island. Such charge injection on the islands may be implemented by Fowler-Nordheim tunneling 360a or channel hot electron injection (CHE)360 b. Once the charge 360a or 360b is injected, the charge can remain in the proper state for many years without a change in state.

For MOSFET devices, the channel resistance depends on the structure and composition of the device, as shown in equation (1) below:

wherein

R ═ channel resistance, in ohms (Ω);

z ═ channel width, in micrometers (μm);

l ═ channel length, in microns (μm);

C_icapacitance per unit area of insulating layer, unit faraday/cm²；

Mu-charge carrier mobility in cm²(v) Volt-sec; and

V_Gand V_TRespectively, an effective gate voltage (in volts) and a threshold voltage (in volts), where V_TDepending on the composition of the device and the states of S1 and S2.

Assuming that the RFID portion 260 is still operational, the deactivation or deactivation process is reversible simply by injecting charge 360a or 360b into the floating gate device 340 or draining charge 360a or 360b from the floating gate device 340 via ground 370. As a result, the aforementioned MOSFET device 300 can be used as an on and off function of either switch S1 or S2.

Power controller 250 may control any floating gate device, such as floating gate device 300. A termination device (kill device), such as an analog termination device, may be coupled across terminals T1 and T2 and may control impedance and loss and read range as well as some RFID functions. Data is input to demodulator 250d via node 2 and output from modulator 250c directly to switch S1, modulation impedance Δ Z, and switch S2. How well the switch S1 or S2 is shorted determines the possible value of the resistance ratio RR.

Embodiments of the invention may be contemplated as dedicated hardware, such as a circuit, an Application Specific Integrated Circuit (ASIC), a Programmable Logic Device (PLD), or a Digital Signal Processor (DSP). In yet another embodiment, the tag 100, semiconductor 130, or reader hardware may be designed using any combination of programmed general-purpose computer components and custom hardware components. The embodiments are not limited in this respect.

While certain features of the embodiments of the invention have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments of the invention.

Claims (13)

1. A semiconductor for Electronic Article Surveillance (EAS) and Radio Frequency Identification (RFID) tags, the semiconductor comprising:

a current receiving portion coupled to the antenna and configured to communicate with at least one other portion of the semiconductor such that upon receiving and forwarding energy and signals from and to the antenna, a plurality of functions can be performed by the at least one other portion of the semiconductor; and

at least one of a first switch and a second switch, the first switch being operatively coupled to the current receiving portion such that upon turning off the first switch, the plurality of functions are disabled, and the second switch being operatively coupled to the current receiving portion such that upon turning off the second switch, the at least one of the plurality of functions is at least partially disabled.

2. The semiconductor of claim 1, wherein at least one of the first switch and the second switch comprises a preset memory.

3. The semiconductor of claim 2, wherein the preset memory sets a conduction state of at least one of the first switch and the second switch.

4. A semiconductor according to claim 3, wherein the conducting state can be set during active operation of the semiconductor and can be maintained by a power controller having a storage device for storing the conducting state when the semiconductor is in the power-off state.

5. The semiconductor of claim 4, wherein the power controller modulates at least one of the first switch and the second switch.

6. The semiconductor of claim 1, wherein the current receiving section is a front end section comprising:

a source electrode;

a drain electrode;

a modulation impedance and a first diode, both operatively coupled to the source and drain electrodes, to form a parallel resonant inductor-capacitor (LC) circuit; and

a second diode operatively coupled to the drain electrode such that the parallel resonant inductor capacitor circuit forms a rectifying circuit.

7. The semiconductor of claim 6, wherein the current receiving portion further comprises a capacitor that enables a resonant frequency of the front end portion to frequency match a frequency of the interrogation signal when received from the antenna.

8. A semiconductor according to claim 1, further comprising an antenna electromagnetically coupled to the semiconductor and designed to receive energy and signals from and forward energy and signals to the current receiving section.

9. An integrated Electronic Article Surveillance (EAS) and Radio Frequency Identification (RFID) tag comprising:

an antenna;

a semiconductor adapted to couple with the antenna and configured to receive and transmit energy and signals to the antenna, the semiconductor comprising:

a current receiving portion disposed in the semiconductor and configured to communicate with at least one other portion of the semiconductor such that upon receiving and forwarding energy and signals from and to the antenna, a plurality of functions can be performed by the at least one other portion; and

at least one of the first switch and the second switch,

the first switch is operatively coupled with the current receiving portion such that upon turning off the first switch, the plurality of functions are disabled; and

the second switch is operatively coupled to the current receiving portion such that at least one of the plurality of functions is at least partially disabled upon turning off the second switch.

10. The integrated marker according to claim 9, wherein at least one of the first switch and the second switch includes a preset memory that sets a conductive state of at least one of the first switch and the second switch.

11. The integrated marker of claim 10, wherein the conductive state can be set during active operation of a semiconductor and maintained by a power controller having a storage device for storing the conductive state when the semiconductor is in a powered down state.

12. The integrated tag according to claim 9, wherein the current receiving portion is a front end portion including:

a source electrode;

a drain electrode;

a modulation impedance and a first diode, both operatively coupled to the source and drain electrodes, to form a parallel resonant inductor-capacitor (LC) circuit; and

a second diode operatively coupled to the drain electrode such that the parallel resonant inductor capacitor circuit forms a rectifying circuit.

13. The integrated tag of claim 12, wherein the current receiving portion further comprises a capacitance such that a resonant frequency of the front end portion can be frequency matched to a frequency of the interrogation signal when received from the antenna.