Electrode arrangement for electronic tags

Abstract

A capacitively coupled radio frequency identification, RFID, tag, and method for reading a tag, the tag comprising: a semiconductor substrate having a first planar surface and a second planar surface distal to the first planar surface; a metallic pad formed on the first planar surface of the semiconductor substrate; a circuit formed on the semiconductor substrate and electrically connected to the metallic pad and the second planar surface of the semiconductor substrate, the circuit configured to respond to a radio frequency (RF) input signal by providing an encoded data signal by varying the impedance between the metallic pad and the second planar surface of the semiconductor substrate, the metallic pad formed on the first planar surface extending beyond the semiconductor substrate; the metallic pad having a rectangular, elongated, or T-shape; and / or the capacitively coupled RFID tag further comprising a metal electrode in electrical contact with the second planar surface.

Description

[Technical Field]

[0001] The present invention relates to capacitively coupled RFID tags and methods for their operation. [Background technology]

[0002] Capacitively coupled tags (CC tags or CCTs) offer reliability and tracking capabilities while providing improved security. This technology is widely used for tracking artifacts where security and reliability are key. However, if the size of CC tags can be reduced and their efficiency increased, then the number of potential applications will increase.

[0003] Other types of RFID tags exist, and these can include an antenna to receive RF signals from a reader to power the device and respond with signals using the same antenna. However, the use of such antennas can increase the size and manufacturing complexity of the device, thereby limiting their applications. Furthermore, such antennas can introduce points of failure, resulting in less robust devices. CC tags do not use antennas, but interact with the RF signals provided by a reader by changing the tag's impedance, which affects the electric field generated by the reader and is in turn detected by the reader. When such impedance changes are modulated, this modulation can be decoded to provide data (e.g., the CC tag's identifier).

[0004] 0.075 x 0.075 mm 2"Ultra-Small 7.5μm Ultra-Thin RFID-Chip Mounting Technology," Hideyuki Noda and Mitsuo Usami, 978-14244-2231-09 / 08, 2008 IEEE, 2008 Electronic Components and Technology Conference, pp. 360-370, describes the fabrication of small RFID chips including antennas. However, the fabrication of such RFID chips, especially in mass production, presents technical difficulties that can reduce yields and increase failure rates in the manufacturing process.

[0005] "Power RFID Chip Technology," Mitsuo Usami, Hitachi, Ltd., 978-1-4244-2342-2 / 08, 2008 IEEE, pp. 1220-1223, describes another small RFID tag and its manufacturing method, which also requires an antenna structure mounted on the RFID chip, which limits the lower tag size.

[0006] 26.6-A 0.05 x 0.05 mm 2 "RFID Chip with Easily Scaled-Down ID-Memory," Mitsuo Usami, Hisao Tanabe, Akira Sato, Isao Sakama, Yukio Maki, Toshiaki Iwamatsu, Takashi Ipposhi, Yasuo Inoue, Hitachi, Ltd., ISSCC 2007 / SESSION 26 / NON-VOLATILE MEMORIES / 26.6, 1-4244-0852-0 / 07, 2007 IEEE, pp. 482-483, describes an RFID chip that has a unique IP address and uses dual surface electrodes.

[0007] A further requirement is that the RFID tag be able to be read in the presence of other RFID tags, which can be particularly difficult for very small RFID tags that may be embedded in many separate items that are stacked or placed near each other. Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, there is a need for a capacitively coupled tag and method of operation that overcomes these problems. [Means for solving the problem]

[0009] A capacitively coupled RFID tag (CC tag or RFID tag) is provided that is formed on a thin (e.g., 100 μm, 50 μm or less) semiconductor substrate such as silicon, with one surface covered with a metal layer (e.g., gold on aluminum) and the other surface being a bare semiconductor surface, with these surfaces acting together as a tunable impedance. A circuit or chip (e.g., an integrated circuit, IC) on or within the semiconductor substrate controls the device and, typically using electrodes, changes its electrical properties as seen (electrically) by an external reader that applies an electric field through the CC tag. The CC tag is powered by an externally applied RF field and responds to its presence by changing its electrical properties (particularly its impedance). The CC tag capacitively couples to the reader, and the IC modulates its electrical properties to encode a data signal that is decoded by the reader. The electrical properties are changed by varying the impedance between the metal layer and the opposing semiconductor layer.

[0010] When two or more such CC tags, or a stack, are placed within the electric field generated by a reader, only one of the CC tags is configured to respond. In an exemplary implementation, the remaining CC tags can reduce their own impedance, for example, by applying a short circuit (e.g., statically) between the metal surface and the opposing semiconductor surface, so that each CC tag can respond in turn and separately and provide an output signal by modulating the RF input signal.

[0011] Also provided is a method for manufacturing a capacitively coupled RFID tag by providing a semiconductor substrate (e.g., silicon) having opposing planar surfaces, applying a metallic layer to one of the surfaces, and forming (e.g., using lithographic techniques) circuitry (e.g., CMOS circuitry) as described throughout this specification on or in the other surface. Preferably, the thickness (i.e., the distance between the opposing planar surfaces) is 50 μm (or 25 μm, 100 μm, or 150 μm) or less. The substrate can be square, rectangular, or another shape. Preferably, the substrate and resulting device are between 50 and 700 μm in width and / or length.

[0012] Applications of these concepts include, but are not limited to, banknotes, visas, stamps, official documents, holograms, foils, cigarettes and tobacco products of any kind (e.g., standard cigarettes and e-cigarettes), bottles, labels, food, food packaging, tablets, and other pharmaceuticals (including their coatings and packaging materials) and other types of packaging materials requiring such small, micron-thick solutions. CC tags can be embedded or affixed to such items.

[0013] Against the previously described background, and according to a first aspect, there is provided a capacitively coupled radio frequency identification (RFID) tag (e.g., CC tag), comprising: a semiconductor substrate having a first planar surface and a second planar surface distal from the first planar surface; a metal pad formed on the first flat surface of the semiconductor substrate; a circuit formed on the semiconductor substrate and electrically connected to the metallic pad and the second planar surface of the semiconductor substrate, the circuit configured to respond to a radio frequency (RF) input signal by providing a data signal encoded by varying an impedance between the metallic pad and the second planar surface of the semiconductor substrate; and Having one side provided with metal pads and the other side with a semiconductor surface reduces manufacturing complexity (over, for example, a CC tag that may have metal pads on each side) because the semiconductor surface is provided by the substrate, while the opposite surface allows for capacitance that can be varied by changing the device impedance between the surfaces. The planar surface may be flat or curved (e.g., to accommodate the shape of the object having the tag attached), while not affecting, for example, the function of the tag.

[0014] Preferably, the data signal may be encoded by the varying impedance between the metallic pad and the second planar surface of the semiconductor substrate to modulate the RF input signal, allowing the RF input signal to be used both to power the device and to be decoded by a reader.

[0015] Preferably, the RF input signal may be provided by an external reader.

[0016] Advantageously, said circuitry is further adapted to be powered by said RF input signal.

[0017] Advantageously, the circuitry may be further configured to decode a signal encoded within the RF input signal, and the data signal is provided in response to the decoded signal. The circuitry may optionally include a small amount of power storage (e.g., a capacitor) for storing power generated by the RF input signal for a short period of time.

[0018] Optionally, said circuitry modulates said RF input signal by varying the frequency, amplitude and / or phase or any other electrical characteristic of said RF input signal.

[0019] Optionally, the circuitry may be formed on or embedded within the second planar surface of the semiconductor substrate.

[0020] Optionally, the circuit may be configured to vary the electrical impedance between the metallic pad and the second planar surface of the semiconductor substrate by applying a short circuit between the metallic pad and the second planar surface of the semiconductor substrate.

[0021] Optionally, the distance between the outer surface of the metallic pad and the second planar surface of the semiconductor substrate is 50 μm or less. This may be described as the thickness of the CC tag. The thickness may alternatively be, for example, 10 μm or less, 25 μm or less, 100 μm or less, or 150 μm or less. The CC tag may have, for example, a substantially square or rectangular cross section.

[0022] Optionally, the circuitry may be further configured to detect the presence of one or more additional capacitively coupled RFID tags (e.g., of the same type) and, in response, cease providing the data signal. This prevents signal collisions and allows multiple CC tags to be read sequentially without having to have only one CC tag within range of the reader at a time.

[0023] Optionally, the circuitry may be configured to stop providing the data signal by applying a short between the metallic pad and the second planar surface of the semiconductor substrate, effectively making the "off" CC tag invisible (electrically) to a reader.

[0024] Optionally, the circuitry may be configured to cease providing the data signal until one or more further capacitively coupled RFID tags have provided their own data signals.

[0025] Optionally, said circuitry may be further configured to cease providing said data signal (ie of its own data signal) in accordance with an anti-collision protocol.

[0026] Optionally, said anti-collision protocol comprises: The one or more capacitively coupled RFID tags may be based on communication between them according to a predetermined sequence of responses, a negotiated response between them, or a random number generator. Such anti-collision protocols may not rely on direct communication between the CC tags, but rather may rely on communication via a reader or no communication at all.

[0027] Optionally, the first planar surface may be parallel to the second planar surface.Other configurations may be used where the surfaces give rise to capacitance.

[0028] Optionally, the capacitively coupled RFID tag is flexible, which can include a bending radius on the order of the width or length of the CC tag, so that the CC tag may be embedded or attached to flexible items with low risk of damage.

[0029] Optionally, the capacitively coupled RFID tag may further comprise a metal plate, which allows a reader electrode to be coupled to the side of the tag facing away from the reader, thus avoiding the need for a reader electrode on the opposite side of the tag.

[0030] Optionally, the capacitively coupled RFID tag may further comprise an insulator laminated between the tag and the metal plate.

[0031] Optionally, the insulator may be laminated to the metal pad of the tag, which may be by adhesive or another suitable method.

[0032] Optionally, the insulator may be laminated to the second planar surface of the semiconductor substrate.

[0033] Optionally, the metal plate may be curved, so that it can adapt to an article, for example a cylindrical or spherical article.

[0034] Optionally, the metallic plate may extend beyond at least one edge of the metallic pad and / or the semiconductor substrate.

[0035] According to a second aspect, there is provided an article having embedded therein the capacitively coupled RFID tag of the previous aspect.

[0036] Optionally, a surface of the article is parallel or substantially parallel to the first planar surface of the capacitively coupled RFID tag, which is useful for flat, planar objects and / or flexible objects.

[0037] Optionally, the article may be formed from paper, from a plastic material, and is a banknote, a passport, an ID card, a tax stamp, a cigarette, an e-cigarette, a label, a tablet (e.g., a medicine), a drink capsule, a coffee capsule, a tea capsule, and / or a legal document.

[0038] According to a third aspect, there is provided a method of communicating with a plurality of capacitively coupled RFID tags, said method comprising: applying a radio frequency (RF) input signal to the plurality of capacitively coupled RFID tags; Responding to the applied RF input by one of the plurality of capacitively coupled RFID tags by altering the impedance of the capacitively coupled RFID tag, the altering the impedance encoding a data signal; detecting a variation in the RF input signal caused by the varying impedance of the one of the plurality of capacitively coupled RFID tags, the variation encoding the data signal; decoding said data signal from said variation of said RF input signal; Including, The non-responding capacitively coupled RFID tags of the plurality of capacitively coupled RFID tags decrease their impedance while the one capacitively coupled RFID tag changes its impedance. Other methods of reading CC tags as mentioned above may be used.

[0039] Optionally, the variation of the RF input signal may be a variation of frequency, amplitude and / or phase.

[0040] Preferably, the method may further include using an anti-collision protocol to determine which one of the plurality of capacitively coupled RFID tags will respond to the radio frequency by changing its impedance.

[0041] Optionally, the multiple capacitively coupled RFID tags may be stacked one above the other or otherwise placed in close proximity to one another.

[0042] According to a fourth aspect, there is provided a computer program comprising program instructions which, when executed on a computer, cause said computer to carry out the method described above.

[0043] According to a fifth aspect, there is provided a computer readable medium carrying a computer program as described above.

[0044] According to a sixth aspect, any one or more capacitively coupled RFID tags as described above; a reader comprising an RF signal generator and a decoder configured to decode a data signal; A system is provided comprising:

[0045] Optionally, said reader: a first electrode configured to align with the metallic pad and / or semiconductor substrate of the tag; a second electrode configured to align with the metallic pad and / or a portion of the metallic plate that extends beyond at least one edge of the semiconductor substrate; The system may further comprise, for example, a tag having a metallic plate that extends beyond the substrate and / or metallic pad.

[0046] Optionally, the metal plate may be formed from a metal packaging such as a can, a tin can, a coffee capsule, a tea capsule or a beverage capsule, etc. Thus, manufacturing of the device may be simplified and the tag may be more effectively used and applied to metal articles.

[0047] Optionally, the first electrode and / or the second electrode may be curved, so that the electrodes can, for example, adapt to a cylindrical or spherical object (e.g., a cigarette or an e-cigarette).

[0048] The above described methods may be implemented as a computer program comprising program instructions for operating a computer. The computer program may be stored on a computer-readable medium.

[0049] A computer system (e.g., implemented within an integrated circuit) may include one or more processors (e.g., local, virtual, or cloud-based), such as a central processing unit (CPU), and / or a single or collection of graphics processing units (GPUs). The processor may execute logic in the form of a software program. A computer system may include memory, including volatile and non-volatile storage media. Computer-readable media may be included for storing logic and program instructions. Different parts of the system may be connected using a network (e.g., wireless and wired networks). A computer system may include one or more interfaces. A computer system may include a suitable operating system, such as, for example, UNIX, Windows (RTM), or Linux.

[0050] It should be noted that any of the features described above may be used in conjunction with any particular aspect or embodiment of the invention.

[0051] The invention may be put into practice in many ways and embodiments will now be described, by way of example only, and with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0052] [Figure 1] FIG. 1 is a schematic diagram of a capacitively coupled RFID tag being read by a reader. [Figure 2] 2 is a schematic diagram of multiple capacitively coupled RFID tags of FIG. 1 being read by a reader. [Figure 3] 1 is a schematic diagram of a further capacitively coupled RFID tag being read by a reader. [Figure 4] 1 is a schematic diagram of a further capacitively coupled RFID tag being read by a reader. [Figure 5]FIG. 5 is a schematic diagram of a system including any of the capacitively coupled RFID tags and readers of FIGS. 1-4 applied to a cigarette or e-cigarette (or other object). [Figure 6a] 6 is a cross-sectional view of the capacitively coupled RFID tag of FIG. 5 when applied to a cigarette or e-cigarette. [Figure 6b] 6b is a schematic diagram of the cigarette or e-cigarette of FIG. 6a together with a reader electrode. [Figure 7] 1 is a schematic diagram of a further plurality of capacitively coupled RFID tags (each attached to an item) being read by a reader. [Figure 8] 1 is a schematic diagram of a further exemplary implementation of a capacitively coupled RFID tag for use in an electronic cigarette. DETAILED DESCRIPTION OF THE INVENTION

[0053] It should be noted that the figures are illustrated for simplicity and are not necessarily drawn to scale, and similar features are given the same reference numerals.

[0054] According to an exemplary implementation, a capacitively coupled tag (CC tag) is a radio frequency identification system (RDID) based on a single integrated circuit (IC). In typical applications, the integrated circuit is a piece of single crystal silicon having one side functionalized through various steps to incorporate electronic components such as, but not limited to, resistors, capacitors, diodes, transistors, etc., connected via metal layers.

[0055] Due to the small size of these components, electrical connectivity to the integrated circuit is provided using the presence of several "pads" or metal layers large enough to connect with small wires or probes. These "pads" are usually located on the functionalized side of the integrated circuit.

[0056] The backside of an integrated IC is usually connected to a ground reference and is of no particular interest at the electronic level. In the present CC tag, one large metallic pad is placed on the functionalized side of the IC, and a second pad is provided on the backside of the device. This structure allows the device to be freely positioned on a surface without the need for any precise positioning or angular orientation, and the device can function regardless of which side of the surface the CC tag is deposited on. This important feature simplifies the deposition process and reduces the associated costs.

[0057] ICs can be formed using CMOS (complementary metal-oxide-semiconductor) technology (i.e., silicon-based technology). Due to the presence of both n-type and p-type metal-oxide-semiconductors on the same silicon substrate, a well-known effect known as "latch-up" can occur. This can be caused by a parasitic thyristor inherently present in CMOS structures, which can be triggered by unexpected voltage spikes and create a short-circuit conduction between the device's positive and negative power contacts. This effect is typically reduced by placing a separate ground contact on the substrate. This effect can even be stronger in CC tags due to the presence of radio frequency (RF) signals coming from the backside pad (i.e., semiconductor), which may be connected to the IC's virtual ground. To avoid this effect, a separate ground contact can be placed near the MOS transistor. Alternatively, other semiconductors can be used, such as gallium arsenide, graphene, germanium, and silicon carbide.

[0058] In this exemplary CC tag, the backside of the integrated circuit (i.e., the pure semiconductor substrate) is used as a potential electrical pad and is placed near a second, larger pad on the top surface (opposite) of the functionalized surface. In this example, the structure takes the form of a thin plate (having a first surface and an opposite surface). The system consists of an integrated circuit with one pad on the top surface and one on the bottom surface (or vice versa, depending on any particular orientation), and the bottom pad may be used as a capacitor plate from a specially developed reader.

[0059] The reader can communicate with the CC tag via a modulated electric field (capacitive coupling) without requiring electrical continuity between the reader and the tag.

[0060] Standard RFID tags have an input stage consisting of an inductor acting as an antenna and a tuning capacitor tuned at the transmission frequency to optimize signal transmission. CC tags, in contrast, only have a capacitor at the input stage. The capacitor exhibits short-circuit behavior at high frequencies, and the cutoff frequency at which this behavior occurs depends on the value of the capacitor itself and the value of the parasitic resistance of the circuit. This approach offers an important advantage, as the coupling capacitor just needs to be "high enough" to exhibit short-circuit behavior without requiring precise tuning of the capacitor itself. This results in much lower dependence on process parameter fluctuations in the deposition process.

[0061] For the same reason, CC tags can even operate at different frequencies simultaneously, the higher the better in general.The solution shown in the figure (explained in more detail below) offers several advantages. - The tags are extremely simple to manufacture, cheap and very robust: they can be easily manufactured together with standard integrated circuit technology. - The tags do not require special alignment with the item to be tagged, which in turn reduces manufacturing complexity and costs. - CC tags can also be read when stacked as the tags implement an anti-collision protocol for tags and readers.

[0062] The CC tag can be thinned to less than 50 μm, resulting in an ultra-thin and flexible tag that can be encapsulated in a variety of applications such as, but not limited to, banknotes, official and government documents, tax stamps, visas, holograms, as well as any packaging material for any item, paper, etc.

[0063] FIG. 1 shows a schematic diagram of a capacitively coupled tag 10 (CC tag) that is powered and read by a tag reader 20. The tag reader 20 includes an electrode 30 that generates a radio frequency (RF) signal to create an electric field 70. This RF signal may be modulated and detected by the capacitively coupled tag 10. As shown in this figure, the upper surface or top side of the capacitively coupled tag 10 has an electrode 40 that is made of metal. The opposite surface or bottom side of the capacitively coupled tag 10 is left bare and forms a semiconductor electrode surface 50. Within or on the surface of the semiconductor substrate of the capacitively coupled tag 10 is a circuit (i.e., an integrated circuit) 60 (not shown in detail in this figure). The electric field 70 is illustrated by arrows between the electrodes 30 of the reader 20. The metal can be aluminum, copper, gold, silver, or a combination of separate metal layers (e.g., gold on aluminum). An IC can be fabricated on or within the surface of the CC tag 10 that does not have a metal pad (i.e., a semiconductor pad surface). Preferably, the surfaces are parallel and flat.

[0064] Figure 2 shows a further schematic diagram of multiple capacitively coupled tags 10 of the same configuration as shown in Figure 1. Again, a reader 20 applies an electric field between the reader's electrodes 30 to read each of the capacitively coupled tags 10. This diagram does not show any articles or substrates attached to each CC tag 10 to simplify the illustration, although this would be present. Figure 7 shows an equivalent arrangement with the articles to be tagged attached to each CC tag 10 in the stack. It is noted that the CC tags 10 do not necessarily need to be perfectly aligned to be read by the reader.

[0065] When there is more than one CC tag 10 between the electrodes 30 of the reader, all but one CC tag 10 responds to the incident RF input signal by modulating the incident RF input signal (i.e., by changing their own impedance to provide a data signal). The remaining CC tags can optionally reduce their own impedance, for example, by shorting their own pads (metallic and semiconducting surfaces). This makes the CC tags electrically invisible to the reader. When the first CC tag is provided with its data signal, it stops modulating the input RF signal and shorts its own pads. Then, another CC tag responds to the input RF signal by modulating the input RF signal as described above. The process continues until all CC tags have been provided with data. Thus, CC tags can be stacked one after the other without a reduction in signal strength.

[0066] Separate CC tags can communicate with each other to determine which one will respond to the signal. This can be achieved using an anti-collision algorithm, which can generate a random delay that results in a different time for each tag's transmission. Alternatively, no communication is required, and each CC tag can respond to an incoming RF signal after a different (e.g., random) delay, which substantially reduces the risk of any two CC tags responding simultaneously (the actual transmission time may be short compared to the delay time).

[0067] Shorting the pads may be accomplished, for example, by one or more transistors changing their state from "off" to "saturated" to act as an on / off switch.

[0068] Additionally, alternative implementations may be used that may include any one or more of the following alternatives or advantages. The CC tag 10 can be embedded in or on the surface of ultra-thin structures (such as paper sheets, banknotes, holograms, postage stamps, etc.) without the need for any antenna, alignment or specific positioning. The CC tag 10 does not require a metallic contact with the reader. Radio frequency (RF) signals can be transmitted from the reader to the CC tag 10 even through a thin insulating layer (less than 1 mm). The CC tag 10 can draw power from the reader when the reader is within reading distance, and can respond by modulating (on / off switching) the impedance between the top and bottom electrodes. The CC tag 10 is much more robust to manufacturing parameter fluctuations since it does not work at circuit resonance and does not suffer from frequency detuning problems. The CC tag 10 can be read while stacked, either aligned with the stack or capacitively coupled using a separate metal layer deposited onto the thin structure. The CC tag 10 can be equipped with an anti-collision solution to prevent two or more tags from communicating with the reader at the same time. When CC tags 10 are stacked and read, they may follow the procedure below: It receives power and data from the reader over a period of time (charging time). If the tag is deemed to respond, it can modulate its own impedance to communicate with the reader. If a tag is not expected to answer, it may reduce the tag's output impedance to a low level (switch on) to allow the reader signal to pass through to a tag that is targeted to answer. When CC tags 10 are read while stacked, they are electrically "in series" with each other. This means that the voltage across the stack is divided by the number of elements in the stack. The reader can provide an adaptive voltage to provide sufficient voltage or power to operate each CC tag 10. This may involve, for example, increasing the applied electric field (e.g., voltage and / or power) to a level such that all of the CC tags can be powered. It should be noted that CC tags 10 may be placed in any orientation between the reader electrodes. For example, the first electrode can be raised or lowered, and the second electrode can be lowered or raised. Different CC tags 10 placed in a stack can be placed in any orientation, which may be different for CC tags 10 within the same stack.

[0069] The previous example describes a CC tag reading technique in which a tag or series of tags is "clamped" between, or preferably placed close to, two reader electrodes (e.g., part of a reader). This approach is particularly applicable to items to be tagged, such as thin structures like paper, banknotes, etc., onto which or within which the CC tag 10 is placed (as shown in FIG. 3).

[0070] In a further exemplary implementation, a "single-sided" readout can be used. This exemplary implementation avoids the need to place reader electrodes on both sides of the article and can therefore be used with larger or thicker objects. This is achieved by adding a separate metal layer (e.g., a suitable conductor such as aluminum, copper, silver, or gold) behind the CC tag on the article, as shown in FIG. 4. While FIG. 4 shows the CC tag positioned on the top side of the article, the CC tag can also be positioned on the side or bottom of the article. The CC tag used in this exemplary implementation can be the same or substantially similar to those described above.

[0071] The metal layer extends beyond or overlaps the CC tag 10 in at least one direction. Two electrodes are again used with the reader. Electrode #1 is positioned above the CC tag 10 (and part of the metal layer) on the object. Electrode #2 is positioned above or aligned with another portion of the metal layer that substantially avoids the CC tag 10 but is not below or aligned with the CC tag 10. Thus, the electrodes can be positioned on the same side of the item while still allowing capacitive coupling with the CC tag 10. In other words, the reader, CC tag, and item are positioned with a first reader electrode, then the CC tag 10 (e.g., directly below the first electrode), then the continuous metal layer, then the item to be tagged. The second reader electrode is adjacent to the first electrode with the same metal layer between the second electrode and the item. In an example implementation, the CC tag 10 can be embedded or partially embedded in an insulator layer (e.g., a polymer or other dielectric) disposed on and substantially overlying a metal layer, as shown in Figure 4. The insulator layer (or a portion thereof) may be directly between the CC tag 10 and the metal layer.

[0072] Some example uses of the CC tag 10 are described above. A further example is the use of the CC tag 10 (of any of the types described above) in consumable products such as electronic or e-cigarettes, beverage capsules, etc. Figure 5 shows an example implementation of this with the CC tag 10 integrated into part of the e-cigarette (e.g., a replaceable part such as a tobacco plug or stick 510) and a reader (or in the example, reader electrode 550) located on another part of the e-cigarette 540. The reader can thus verify whether the e-cigarette has the presence of a correct or legal replacement part.

[0073] In this example, the conductive electrode may be printed on or incorporated into paper, e.g., the outer packaging of the e-cigarette, with the CC tag 10 incorporated into either a hollow acetate tube or a polymer membrane filter. The reader electrode or electrodes 550 may be incorporated into the packaging tip (ejector side) of the e-cigarette. The reader electrode may, for example, be incorporated in the same volume as the existing control electronics of the e-cigarette.

[0074] 5, electrodes 520 may also be located on the tobacco plug 510. However, the CC tag 10 may also operate without such external electrodes. A printed circuit board 505 may be used to mount the various components of the system so that the reader electrodes 550 and associated contacts 530 may be coupled to the reader (e.g., using RF communications). These portions of the system may be housed within a case 580 and electrically coupled (e.g., using a USB connector 570) to provide data and power connectivity to a computer or microprocessor 560.

[0075] 6a shows in more detail how such a CC-tag 10 can be formed with a cigarette or e-cigarette (or other cylindrical object) 605. This figure illustrates schematically how a metal backplane or metal plate 620 accommodates the curved surface (e.g., cylindrical) of the e-cigarette 605 and an insulating layer 610 that separates this metal plate 620 from the CC-tag 10. This figure also shows the reader electrodes 630 surrounding the e-cigarette 605 and CC-tag 10.

[0076] Figure 6b illustrates schematically how such a CC tag 10 (with a metal back electrode or backplane metal layer similar to that shown in Figure 4) can be read within a ring-shaped metal reader electrode (550, 550') that surrounds the cigarette or e-cigarette 605. Such an electrode operates in a similar manner to that described above.

[0077] Such CC tags 10 (i.e., those that can be read by a single-sided or adjacent electrode reader) can be more easily read when applied to articles such as labels, packaging materials, holograms, coatings (e.g., tablet coatings), other pharmaceuticals, and irregular or non-flat articles. Figure 6b shows how the metal plate 620 extends beyond the substrate and / or metal pads of the CC tag 10, such that one reader electrode 550' covers the metal plate 620 but not the rest of the CC tag 10, and the other reader electrode 550 covers the rest of the CC tag 10. The metal plate therefore capacitively couples a signal to the far or opposite electrode of the CC tag 10 (i.e., to the other side or opposite to the side where the reader electrode is located).

[0078] While Figures 5, 6a and 6b are shown using the particular CC tag 10 described throughout this specification, similar configurations (i.e., electrode configurations) can be used with different capacitively coupled tags.

[0079] In example implementations, the metal plate can instead be formed from part or all of the article or object to which the tag is attached. For example, the object can be a metal or foil capsule, a can, a tin can, or a carton with an enclosed product. The article can be, for example, disposable or reusable. It could be a beverage capsule, coffee capsule, or tea capsule with an aluminum body. In these examples, the article itself (or at least the metal container) has the same function as the metal plate and can be capacitively coupled to one of the reader electrodes, avoiding the need for electrodes on both sides of the CC tag 10 and also improving the use of the CC tag 10 when applied to conductive articles.

[0080] The problem to be solved is the integration of capacitive tags and electrodes, consisting for example of capacitive chips, into tobacco sticks for mass production.

[0081] The back electrode of the capacitive tag can be incorporated into the paper that is wrapped around the tobacco stick (e.g., by printing or interweaving a metallic conductor), the capacitive chip can be attached to the top surface of the electrode (alternatively with additional adhesive for greater holding strength), and the assembly can be rolled using the mouthpiece paper to hold the capacitive chip (CC tag) in place.

[0082] Such an assembly has the advantage of being integrated into current manufacturing processes for cigarette or e-cigarette tobacco sticks.

[0083] Alternatively, the back electrode can be incorporated into either a hollow acetate tube, a cellulose acetate mouthpiece, or a polymer membrane filter cooler (see below). The capacitive chip (i.e., any of the CC tags described throughout) can then be affixed to one of the three listed components. The position of the chip would then be maintained by paper wrapped around the tobacco stick.

[0084] Alternatively, and in addition to incorporating one electrode into the hollow acetate tube or the cellulose acetate mouthpiece, a second electrode can be incorporated into the paper wrapped around the tobacco stick or the paper for the mouthpiece, respectively, around the polymer membrane filter cooler and the paper, but the second electrode preferably only partially covers the first electrode. In such a configuration, the first electrode is in contact with or near the back electrode of the capacitive chip (CC tag), and the second electrode is in contact with or near the top electrode of the capacitive chip, resulting in improved read sensitivity of the capacitive tag (CC tag).

[0085] While Figures 6a and 6b show the CC tag 10 disposed within an e-cigarette 605, Figure 8 illustrates some alternative implementations of this arrangement. Figure 8 illustrates specific four-electrode configurations (V01, V07, V01b, and V08) for a CC tag 10 used with an e-cigarette 605 or other cylindrical or curved object. The reader electrodes 550, 551' have an annular shape and fit snugly around (or at least partially around) the e-cigarette 605 or e-cigarette cartridge (e.g., tobacco product). The CC tag 10 is coupled to the top and bottom surfaces of the substrate of the CC tag 10 using the aforementioned electrodes 550, 551', which allows the CC tag 10 to be read in a single-sided approach (i.e., from one side of the substrate of the CC tag 10). In the examples V01 and V07 shown in FIG. 8, two metal electrodes (eg, pads) 840, 840' are electrically connected to the surface of the substrate of the integrated circuit 810 of the CC tag 10 and are capacitively coupled with the reader electrodes 550, 551'.

[0086] In versions V01b and V08 of Figure 8, there is only one metal electrode (e.g., metal pad or metallic pad) 850. This corresponds to the metal electrode 40 described with reference to Figure 1. This single electrode 850 capacitively couples the bottom of the substrate to one of the reader electrodes 550. The top surface of the tag 10 substrate is directly capacitively coupled to the other reader electrode 550'. Connectivity between the CC tag 10 and the electrodes 550, 550' may be achieved by direct contact (i.e., electrical contact) or by close proximity, i.e., capacitive coupling. The tag electrodes 810, 840, 840' may be formed in a T-shape (see V01b) or H-shape (see V01) to enhance capacitive coupling with the reader electrodes 550, 550' (i.e., by increasing the aligned surface area). The portions of the metal electrodes 840', 850 in configurations V01 and V01b that are perpendicular to the axis of the cylindrical e-cigarette are curved to conform to the cylindrical surface of the e-cigarette (or e-cigarette refill or cartridge) and to extend partially away from around the periphery of the e-cigarette (e.g., the top of the "T" for a T-shaped electrode and the side of the "H" for an H-shaped electrode).

[0087] Those skilled in the art will recognize that details of the above-described embodiments can be changed without departing from the scope of the invention as defined in the appended claims.

[0088] For example, the CC tag and reader can operate using a standard Industrial, Scientific, and Medical (ISM) radio band frequency (i.e., the frequency of the input RF signal). The frequency of operation can be, for example, 13.56 MHz (or between 10 MHz and 15 MHz). The CC tag can operate at a different frequency (i.e., to avoid data signal collisions). The reader can, for example, scan at a different frequency.

[0089] Many combinations, modifications, or variations on the features of the above-described embodiments will be readily apparent to those skilled in the art and form a part of the invention. Any of the features specifically described in connection with one embodiment or example can be used in any other embodiment, by making appropriate modifications.

Claims

1. 1. A capacitively coupled radio frequency identification (RFID) tag, comprising: a semiconductor substrate having a first planar surface and a second planar surface distal from the first planar surface; a metal pad formed on the first planar surface of the semiconductor substrate; a circuit formed on the semiconductor substrate and electrically connected to the metallic pad and the second planar surface of the semiconductor substrate, the circuit configured to respond to a radio frequency (RF) input signal by providing an encoded data signal by varying an impedance between the metallic pad and the second planar surface of the semiconductor substrate, the metallic pad formed on the first planar surface extending beyond the semiconductor substrate; and Equipped with the metallic pad is rectangular, elongated, or T-shaped, and / or the capacitively coupled RFID tag further comprises a metallic electrode in electrical contact with the second planar surface; A capacitively coupled radio frequency identification (RFID) tag.

2. 10. The capacitively coupled RFID tag of claim 1, the metal electrode in electrical contact with the second planar surface is configured to align with an electrode of a reader comprising an RF signal generator and a decoder configured to decode the data signal, and / or the metal pad and the metal electrode in electrical contact with the second planar surface are configured to form an H-shape.

1. A capacitively coupled RFID tag comprising:

3. 3. The capacitively coupled RFID tag according to claim 1, the data signal is encoded by modulating the RF input signal with a varying impedance between the metallic pad and the second planar surface of the semiconductor substrate.

1. A capacitively coupled RFID tag comprising:

4. 4. The capacitively coupled RFID tag according to claim 1, the circuitry is further configured to decode a signal encoded within the RF input signal; and wherein the data signal is provided in response to the decoded signal.

1. A capacitively coupled RFID tag comprising:

5. 5. The capacitively coupled RFID tag according to claim 1, the circuit is configured to vary the impedance between the metallic pad and the second planar surface of the semiconductor substrate by applying a short between the metallic pad and the second planar surface of the semiconductor substrate; 1. A capacitively coupled RFID tag comprising:

6. 6. The capacitively coupled RFID tag according to claim 1, the circuitry being further configured to detect the presence of one or more additional capacitively coupled RFID tags and, in response, cease providing the data signal.

1. A capacitively coupled RFID tag comprising:

7. 7. The capacitively coupled RFID tag of claim 6, the circuitry is configured to cease providing the data signal until one or more additional capacitively coupled RFID tags have provided their own data signals by applying a short between the metallic pad and the second planar surface of the semiconductor substrate, and / or the circuitry is further configured to cease providing the data signal in accordance with an anti-collision protocol.

1. A capacitively coupled RFID tag comprising:

8. 8. The capacitively coupled RFID tag of claim 7, if the circuitry is further configured to cease providing the data signal in accordance with an anti-collision protocol, the anti-collision protocol being based on a predetermined sequence of responses, negotiated responses between the one or more capacitively coupled RFID tags, or communication between the one or more capacitively coupled RFID tags in accordance with a random number generator; 1. A capacitively coupled RFID tag comprising:

9. 9. The capacitively coupled RFID tag according to claim 1, the first planar surface is parallel to the second planar surface, and / or the circuit is formed on the second planar surface of the semiconductor substrate; 1. A capacitively coupled RFID tag comprising:

10. 10. The capacitively coupled RFID tag according to claim 1, Further comprising a metal plate; the metallic plate is curved and / or extends beyond at least one edge of the metallic pad and / or the semiconductor substrate; 1. A capacitively coupled RFID tag comprising:

11. 11. The capacitively coupled RFID tag of claim 10, an insulator bonded between the capacitively coupled RFID tag and the metal plate; a capacitively coupled RFID tag, characterized in that the insulator is bonded to the metal pad of the tag, or the insulator is bonded to the second flat surface of the semiconductor substrate.

12. An article having the capacitively coupled RFID tag according to any one of claims 1 to 11 embedded therein.

13. 13. The article of claim 12, a surface of the article is parallel to the first planar surface of the capacitively coupled RFID tag; and / or the article is formed from a paper or plastic material, and the article is a banknote, a cigarette, an e-cigarette, a label, a tablet, a medicine, a drink capsule, a coffee capsule, a tea capsule, a metal container, a hologram, a passport, an ID card, a tax stamp and / or a legal document; An article characterized by:

14. One or more capacitively coupled RFID tags according to any one of claims 1 to 11; a reader comprising an RF signal generator and a decoder configured to decode the data signal; A system comprising:

15. 15. The system of claim 14, The reader: a first electrode configured to align with the metallic pad and / or semiconductor substrate of the tag; and / or a second electrode configured to align with at least a portion of the metal electrode in electrical contact with the second planar surface; Further provided with A system characterized by:

16. 16. The system of claim 15, the first electrode and / or the second electrode are curved or annular, and / or the first electrode and the second electrode are arranged parallel to each other; A system characterized by:

17. 17. A system according to any one of claims 14 to 16, comprising: The electronic cigarette further comprises an electronic cigarette attached to the one or more capacitively coupled RFID tags, and / or the metal plate is formed from a can, a tin can, a metal package of a coffee capsule, a tea capsule or a beverage capsule. A system characterized by:

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