Wireless communication device and method for discs

A compact disc coupled to a wireless communication device comprises the disc with a metalized outer portion, a wireless communication chip and a pair of tabs. The first tab may capacitively couple the wireless communication chip to the metalized portion of the disc. The second tab may be positioned in an inner portion of the disc with a gap delimited by the metalized portion and the second tab. A slot antenna is thus formed through which the wireless communication device may communicate. Wireless communication chip allows disc to be interrogated and identified for a variety of purposes, including, but not limited to security, advertising and promotion, and issuing of related coupons to customers for subsequent purchases.

FIELD OF THE INVENTION

The present invention relates to an apparatus, system and method of providing wireless communication devices in discs and communicating of information concerning the disc containing the wireless communication device.

BACKGROUND OF THE INVENTION

It is often desired to track and identify items, such as packages, containers, discs, etc., and to communicate information concerning such items wirelessly. One method of tracking and providing information concerning packages is to attach a wireless communication device, such as a radio frequency identification (RFID) transponder or other identification device, to packages. The information communicated concerning the packages may include identification information, expiration dates, “born on” dates, lot numbers, manufacturing information, and the like. A wireless communication device may be attached to an individual package or to a container containing multiple packages.

A problem exists when a wireless communication device is attached to packaging or containers constructed out of a conductive material such as foil, or comprised of a metalized or conductive portion. A pole antenna connected to the wireless communication device will not radiate properly if the wireless communication device is attached on the outside of the package. The pole antenna will be shielded if the wireless communication device is placed inside the package.

In addition to conductive materials, wireless communication devices are also used with many other substrates. Each substrate has its own dielectric characteristics that typically affect the impedance matching between the wireless communication device and its antenna. Impedance matching ensures the most efficient energy transfer between an antenna and the wireless communication device.

One particular item for which tracking may be desirable is a disc. Discs can be any type of circular substrate, but the present invention address discs that store digital information in particular such as compact discs or mini discs. Note that in this context, the term “mini disc” does not refer to the trademark used by SONY, but rather to a miniature compact disc that is optically read. Most compact discs and mini discs are made from a metalized outer portion and a plastic inner portion. Digital video discs or Digital versatile discs (collectively DVDs) are made from substantially the same structure. This tracking may be for identification, such as in a retail outlet, computer system or jukebox (for compact-discs), theft prevention, authenticity purposes or the like as needed or desired.

It may be also advantageous for such a wireless communication device to communicate on different frequencies so that one device can be used for various applications. For instance, an operating frequency of 2.45 GHz is used frequently outside the United States, but an operating frequency of 915 MHz is frequently used in the United States. Many companies manufacture wireless communication devices that are capable of operating at both 915 MHz and 2.45 GHz frequencies so that either frequency can be chosen for operation. However, wireless communications device applications, such as attaching wireless communication devices to packages for informative and tracking purposes, configure the device to communicate on only one frequency—either a frequency for the United States or a frequency for use abroad. It would be advantageous to construct a wireless communication device with an antenna structure that is capable of communicating at more than one frequency. This would allow one wireless communication device to be applicable for uses in both the United States and abroad.

SUMMARY OF THE INVENTION

The present invention relates to a wireless communication device for use in conjunction with a disc, such as a compact disc, mini disc or digital video disc, or comparable item. In particular, an antenna is formed with a conductive tape or the like attached to a center portion of the disc. The metalization of the disc coupled with the tape, form a slot antenna for operation at a first frequency. Further, conductive tabs may be used to couple to the slot in such a fashion that the tabs form an antenna at a second frequency. These conductive tabs may also serve the purpose of delimiting the length of the slot regardless of their use as a second antenna.

It should be appreciated that the parent applications discussed wireless communication devices associated with a package, container or other material to communicate information concerning the package, container or other material. A wireless communication device is provided that contains a control system, communication electronics, memory, and an antenna. The wireless communication device may contain a sensor to sense environmental conditions surrounding the wireless communication device. The wireless communication device contains one or more tabs constructed out of conductive material. The tab(s) may serve as both a pole antenna and may attach the wireless communication device to a slot, thereby forming a slot antenna. While helpful in some embodiments such is not required in all the embodiments herein presented.

In one embodiment, the wireless communication device is a transponder that is interrogated by an interrogation reader for communication purposes. The wireless communication device is attached to a package that may be constructed out of a conductive material, such as foil packaging used for food or liquid.

In another embodiment, the tab(s) form a pole antenna to communicate in a first mode at one frequency, and the tab(s) are attached across a slot in a package to communicate in a second mode at a second frequency. One tab is used in one embodiment to form a monopole type antenna, and two tabs are used in another embodiment to form a dipole antenna. In another embodiment, the tab(s) can be varied in shape and size to adjust to surfaces that vary in form.

An asymmetrical antenna arrangement may be provided so that the impedance of the antenna is not substantially affected by the substrate to which the wireless communication device is attached. In one embodiment, the asymmetrical antenna arrangement is an asymmetrical dipole antenna formed by asymmetrical tabs. For example, the wireless communication device may be placed in an indentation in the substrate so that the wireless communication device does not protrude from the substrate surface. Asymmetrical tabs are placed on the surface of the substrate. The asymmetrical tabs are connected to the wireless communication device with feed lines to provide an asymmetrical dipole antenna. In a second embodiment, the asymmetrical antenna arrangement is an asymmetrical slot antenna.

In another embodiment, a wireless communication device placed onto a disc, such as a compact disc or video disc, is used in conjunction with an interrogator to identify a disc for either promotional or security purposes. A customer may purchase a compact disc or video disc in a retail store. As the customer leaves the retail store, an interrogator determines the identification of the disc purchased by the customer and displays and/or plays a special message to the customer. If an interrogator detects an unpurchased disc leaving the retail store, the interrogator may indicate an alert and/or alarm condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a particular wireless communication device positioned on a disc. However, this technology builds on a line of patent applications with related subject matter. This related subject matter is presented in full below, with the new material described with reference toFIGS. 18 and 19following. For the purposes of the present invention, the term “mini disc” is a miniaturized optical disc. The term “DVD” includes digital video discs and digital versatile discs, the latter capable of storing computer data as well as video data. The prior inventions were directed to a device, system and method of attaching a wireless communication device, such as a radio frequency identification device (RFID), to a package or container to communicate information about the package or container. The package may be an individual package containing specific contents, or an individual, exterior package containing a group of additional, interior individual packages. The word “package” and “container” are used interchangeably herein to describe a material that houses contents, such as goods or other individual packages, and equivalent structures. The present invention should not be limited to any particular meaning or method when either “package” or “container” is used.

As illustrated inFIG. 1, the invention includes a wireless communication device10for electronic communication. Some wireless communication devices10have both a transmitter and receiver. Other wireless communication devices10, known in the art as “transponders,” are interrogated by interrogation reader50, whereby the transponder communicates back by altering field58containing interrogation signal56. This description refers to the terms “transponder” and wireless communication device10interchangeably, and the use of the term transponder is not intended to limit the type of wireless communication device10applicable to the present invention. Wireless communication devices10are available that communicate at various frequencies, including UHF and VHF. One embodiment of the present invention uses a wireless communication device10, also called a “transponder,” that is a passive radio-frequency device with the ability to rectify incoming radio energy and provide power to power the device for communication and operation. The invention is also applicable to active devices that have their own power source for communications. It should be readily understood to one of ordinary skill in the art that there are many other different types of wireless communication devices10that allow electronic communication and thus the present invention is not limited to any one particular type.

Transponder10includes a control system12and communication electronics14. Transponder10may also contain memory18for storage of information to be communicated to an interrogation reader50. Alternatively, transponder10may store information such as an identification number or other information by using diodes, dip switches or some other like circuitry in lieu of erasable memory18. Antenna16is provided to receive the interrogation signal56from interrogation reader50. Antenna16may be either external to or internal to transponder10. The particular type and location of antenna16will depend on the operating frequency of transponder10and the particular design desired. Transponder10may also be connected to sensor20for sensing ambient or environmental information surrounding transponder10, package200containing transponder10, or the contents of package200. One example of sensor20may be a quartz crystal resonator like that described in U.S. Pat. No. 5,922,550, entitled “Biosensing devices which produce diffraction images,” incorporated herein by referenceinits entirety. A quartz crystal resonator detects analytes that may be present in food. Analytes include, but are not limited to, microorganisms such as bacteria, yeasts, fungi and viruses.

Antenna16receives signal56through the radiated interrogation field58. Antenna16passes received signals56to communication electronics14. Communication electronics14contain circuitry necessary to interpret signal56from field58and to further communicate the interpreted signal to control system12. Control system12is an integrated circuit, printed circuit board, or other type of microprocessor or micro-controller electronics that controls the operations of the transponder10. Control system12is connected to communication electronics14to communicate and receive transmissions. Control system12is also connected to memory18for storing and retrieving information. Control system12may further include a clock (not shown). Control system12determines if any actions are needed in response to the communications received from communication electronics14.

FIG. 1also depicts how communication is achieved with transponder10using an interrogation reader50. Interrogation reader50contains interrogation communication electronics52and an interrogation antenna54. Interrogation reader50communicates with the transponder10by emitting an electronic signal56modulated in a frequency by interrogation communication electronics52through interrogation antenna54. Interrogation antenna54may be any type of antenna that can radiate signal56through a field58so that a compatible device, such as transponder10, can receive such signal56through its own antenna16. Field58could be electro-magnetic, magnetic, or electric. Signal56is a message containing information or a specific request for the transponder10.

When antenna16is in the presence of field58emitted by interrogation reader50, communication electronics14are energized by signal56, thereby energizing transponder10. Transponder10remains energized so long as antenna16is in the field58of interrogation reader50. Communication electronics14demodulates signal56and sends the message containing information or request to control system12for appropriate actions. For example, the request may be for transponder10to communicate its identification, or information about a material or package containing transponder10, such as date of manufacture, place of manufacture, and/or lot number. The message may also be a request for information regarding ambient or environmental measurements sensed by sensor20.

Another description of a transponder10that may be used with the present invention is located in U.S. Pat. No. 5,347,280, entitled “Frequency diversity transponder arrangement,” incorporated herein by reference in its entirety. Transponder10is one type of wireless communication device. Other types of wireless communication devices10may be used with the present invention. For instance, transponder10may have a transmitter that can send information to interrogation reader50without having to alter signal56. Transponder10may contain a battery to power the transmitter, or an energy storage unit that is charged by energy received from signal56when wireless communication device10is in the range of field58. It is readily understood to one of ordinary skill in the art that there are many other types of wireless communications devices and communication techniques than those described herein, and the present invention is not limited to a particular type of device, technique or method.

Transponder10may be attached on any type of device or package to identify and communicate information concerning the device or package. For instance, transponder10can be attached to a food package and may contain identification information and other information about the food contained inside the package, such as its date of manufacture, “born on” date, expiration date for sale or consumption and lot number. For example, transponder10can be attached to a wine bottle and contain information concerning the type of wine and its ingredients or make up, the date of manufacture, and expiration dates, if applicable. Transponder10can be attached to virtually any device or package conceivable.

FIG. 2illustrates transponder10attached to a food package200. Antenna16can either be a slot antenna16A, as illustrated inFIG. 2, or a pole antenna16B, as illustrated inFIGS. 3A and 3B. A slot300is provided in package200to provide a slot antenna16A. Package200includes a surface202. At least one tab, made out of conductive material, such as a metallic material, is attached to transponder10, and more particularly to communication electronics14inside transponder10. Two or more tabs100may also be attached to transponder10to provide antenna16. The use of “tab” is used in singular and plural herein, and reference in either form is not intended to limit the invention to only one tab100, or more than one tab100.

Tabs100are attached to slot300to form a slot antenna16A. For the purposes of this specification, the word “attached” is used generically to mean either attached directly or connected to slot300. The tabs100may either be attached on slot300or proximate to slot300. Tabs100may also serve as pole antenna16B. Tabs100may also be constructed by applying a conductive fluid (e.g. conductive ink) onto surface202.

The present invention can also be used with transponder10containing one tab100to form either slot antenna16A or pole antenna16B. One tab100can be used to form pole antenna16B in the form of an antenna having monopole-like radiation pattern. If one tab100is used to form slot antenna16B, tab100is attached to slot300, and transponder10is attached, in the form of grounding, to slot300to form a ground plane. Using one tab100as a slot antenna16B will create a monopole-like radiation pattern.

If surface202is constructed out of a conductive material, it may be advantageous to use tabs100to create a slot antenna16A rather than a pole antenna16B. Examples of conductive surfaces202include food foil packaging, wine bottles cork foil, jewelry, watches, cigar label foil, and alcoholic bottle foil labels. If tabs100are attached on a conductive surface202without forming a slot antenna16A, the radiation pattern of the resulting pole antenna16B created by tabs100may not be properly tuned to the operating frequency of transponder10. Factors such as the conductivity and surface area of surface202affect the radiation pattern of a pole antenna16B formed by tabs100when tabs100are attached to surface202. Packages200vary greatly in size, shape, and area. It is desirable for transponder10and tabs100to be manufactured such that transponder10operates at a desired frequency when using tabs100as a pole antenna16B, regardless of the particular characteristics of package200.

Packages200that are constructed out of conductive material, such as foil, containing transponder10inside the package200cannot use a pole antenna16B. The radiation pattern of pole antenna16B is shielded by the conductive material. Therefore, another reason for using tabs100to create a slot antenna16A rather than a pole antenna16B may be so that packages constructed out of conductive material and containing transponder10inside package200can effectively communicate desired information wirelessly.

If tabs100are attached on surface202that is not conductive, tabs100can function at the desired operating frequency as a pole antenna16B, regardless of the characteristics of package200. If two tabs100are used, the tabs100serve as a dipole antenna16B. One tab100, instead of two tabs100, may also be used to serve as antenna16, creating a monopole type radiation pattern as previously described above. A ground plane may be provided between transponder10and surface202such that communication electronics12is attached to surface202to from a ground. In summary, tabs100can serve to provide either a pole antenna16B or slot antenna16A depending on the package200and its characteristics.

FIGS. 3A,3B and3C illustrate transponder10shown inFIG. 2in more detail.FIG. 3Aillustrates transponder10from a top view perspective. Tabs100are made out of a conductive material. For example, tabs100may be constructed out of metals, such as aluminum or copper.FIG. 3Billustrates transponder10from a side view perspective. Tabs100can either be attached directly to surface202or coupled to surface202by placing tabs100on an optional dielectric adhesive material102that is attached to surface202. Use of adhesive material102may be necessary to attach the transponder10to surface202. If transponder10is attached on a package200constructed out of a conductive material without a slot300, such that tabs100act as a dipole antenna16B, a dielectric material102may be attached between the surface202and tabs100so that the radiation pattern of the dipole antenna16B is not affected by the conductive package200. If such a dielectric material102is used, tabs100are reactively coupled, rather than directly connected, to surface202. One tab100, instead of two tabs100, may also be used to serve as antenna16, creating a monopole type radiation pattern. If transponder10, with tabs100, is attached across a slot300in a conductive surface202, a slot antenna16A is formed for antenna16.

A transponder10may be attached to a slot antenna16A as part of its construction, instead of using a slot300created in package200to form a slot antenna16A.FIG. 3Cillustrates slot300as a rectangular, conductive material250having a hollow portion cut out to form an inner, non-conductive portion252. Tabs100are attached to non-conductive portion252. Slot300may be constructed in any shape desired so long as slot300is constructed out of a conductive material250that contains an inner, non-conductive portion252. This inner, non-conductive portion252can be air, formed by a cut out as illustrated inFIG. 3C, or can be formed by placing a non-conductive material, such as plastic, onto or inside conductive material250. The conductive material250may also contain an adhesive102, so that slot300, with transponder10attached, can be easily attached to package200. It may be desirable to provide slot300as part of transponder10, instead of package200, insofar as this eliminates the requirement to create a slot300in package200as part of the construction of package200. For example, it may be impractical or impossible to provide a slot300in package200, but still desirable to attach transponder10to package200using a slot antenna16A. As an additional advantage of this embodiment illustrated inFIG. 3C, since slot300is provided as part of transponder10, package200can be constructed out of non-conductive material.

FIG. 4illustrates transponder10with tabs100acting as both a pole antenna16B and slot antenna16A. A slot300is provided by cutting out a portion of conductive surface202. The length of the tabs100define the operating frequency of the antenna16if tabs100are configured to act as a pole antenna16B. In one embodiment, the tabs100are each ¼ in length, or 30.6 millimeters each, to form a dipole antenna16B with a total length of ½ and an operating frequency of 2.45 GHz.

As previously discussed, tabs100may also serve to form a slot antenna16A if attached across a slot300in a conductive surface202. The slot300length defines the operating frequency of the slot antenna16A. In one embodiment, the slot300length is ½ or 164 millimeters so that the transponder10operates at a frequency of 915 MHz. More information on slot antennas16A and their operation is described in U.S. Pat. No. 4,975,711, entitled “Slot antenna device for portable radiophone,” incorporated herein by reference in its entirety.

In this manner, the transponder10has two antenna16configurations that are capable of communicating at two frequencies. If transponder10is capable of communicating at two different frequencies, as discussed above, the pole antenna16B and slot antenna16A can be configured to communicate at different frequencies as well, enabling the transponder10to effectively communicative at both frequencies. This arrangement provides an advantage in particular if 915 MHz is a desired frequency. 915 MHz is frequently used as an operating frequency for electronic communication in the United States, but 2.45 GHz is frequently used outside the United States. Therefore, providing transponder10with the capability of communicating at both 915 MHz and 2.45 GHz is advantageous so that transponder10can be used for applications in both the United States and abroad. However, if this dual capability is not required, transponder10can be configured to operate solely using a pole antenna16B or slot antenna16A.

FIGS. 5A and 5Billustrate transponder10attached across slots300of varying widths. The width of slot300affects the impedance of slot300. For example, a wider slot300, illustrated inFIG. 5A, may have a higher impedance than the narrower slot300, illustrated inFIG. 5B. Varying the slot300width varies the impedance of the slot antenna16B to maximize antenna16strength. It is desirable to match the impedance of slot300to the impedance of transponder10. In the one embodiment, the slot antenna16A has a fairly low impedance. Therefore, it is desirable to transform the slot300impedance so as to match the impedance of transponder10, thereby maximizing energy transfer between transponder10and slot300and maximizing the strength of the radiation pattern emitted by the slot antenna16A. Matching the impedances also minimizes reflection in the radiation pattern of slot antenna16A. Transponder10may comprise more than one layer, including conductive, dielectric and magnetic materials, such as ferrites, to introduce inductance, thereby aiding modification of the characteristics of surface202for impedance matching purposes.

In addition to the composition of transponder10, the area of tabs100affect the impedance of transponder10. As discussed above, it is desirable to match the impedance of transponder10and slot300. Tabs100can also be varied to ensure optimal coupling to surface202. The impedance of slot300may be varied for matching purposes by modifying relevant characteristics of surface202. For example, a conductive package for food (e.g. foil) may have a surface202that is variable in width, dielectric or metallic characteristics. Capacitance of tabs100may be taken into consideration for impedance matching when attaching tabs100to a particular surface202. The capacitance of tabs100affects the impedance of transponder10. The total volume of tabs100(surface area times thickness) affects their capacitance. Tabs100are similar to parallel plate capacitors in series with wireless communication device10. The larger the volume of tabs100, the larger their capacitance. It is therefore desirable to design and construct tabs100with a capacitance that is commensurate with surface202to match impedance of transponder10and slot300for optimal performance.

An impedance matching network may also be used to match slot300impedance to transponder10impedance, as discussed in patent application Ser. No. 09/536,334, entitled “Remote Communication Using Slot Antenna,” assigned to assignee of the present invention, and incorporated herein by reference in its entirety.

FIG. 6illustrates two slots300A,300B in surface202that are substantially perpendicular to each other, with tabs100attached across the slots300A and300B. The tabs100are attached to slots300A,300B at vertical angles, but tabs100can also attach to slots300A,300B adjacent to each other. This structure creates a circularly polarized slot antenna16A. Tabs100are attached to each of slots300A and300B. The length of the first slot300A, a, is slightly shorter than ½. The length of the second slot300B, b, is slightly greater than ½. The two slots300A,300B provide antennas16that can be considered resonant circuits, with their associated phase delay at the operating frequency of ±45 degrees to each other. This causes transponder10to receive efficiently radiation in more than one dimension and, specifically, in the for of a circular pattern so that the orientation of transponder10on surface202is somewhat irrelevant for communication.

FIG. 7illustrates another type of package200containing transponder10. Package200is configured to contain gum sticks (not shown). The package200is constructed out of a conductive material. Gum sticks are wrapped in their own individual foil wrappers and are placed inside paper non-conductive wrappings900contained inside package200. Parts of the non-conductive wrappings900touch or couple to the interior of package200. Such attaching or coupling provides a slot antenna300as previously discussed, where the non-conductive wrappings provide slot300and the package200inside provides the surrounding conductive material.FIG. 7illustrates transponder10placed inside package200. Tabs100are attached to slot300, as previously described, to provide communication. Again, tabs100are also capable of operating as a pole antenna16A. The package200could also be a cigarette package200. Again, the tabs100may be attached to a slot300, formed by conductive material of the package200surrounding to an internal non-conductive portion internal to package200, to form slot antenna16A. In a variation on this embodiment, the slot300may be the dielectric that forms the tear away strip that allows such packages to be opened.

FIGS. 8A and 8Billustrate particular manners in which transponder10is placed inside package200.FIG. 8Aillustrates transponder10located inside the top of package200where package200opens and seals in a pouch-like fashion. The inside surface202of package200is a conductive material, such as a foil, including the sides of package200that come together when package200is closed and sealed. As discussed previously, it is desirable to configure transponder10to communicate using a slot antenna16A when transponder10is inside a package200constructed out of conductive material. In this embodiment, slot antenna16A is not formed by cutting out a portion of surface202, but rather by inserting a non-conductive material302, such as a dielectric, inside package200at the top to for a seal306where the sides come together. In this manner, a slot300is formed by the separation of the conductive material of inner surface202when the sides of package200, are closed and sealed. Such a method of placing a transponder10inside a package200may be advantageous where it is desired to protect transponder10from theft, tampering or other unwanted elements.

Placing transponder10inside package200may also be useful to indicate if package200has been opened, and, therefore, possibly contaminated. Packages200that contain food for consumption or medical devices and equipment requiring sterility are also possible applications. Transponder10is placed inside package200as previously discussed and illustrated inFIGS. 8A and 8B.

One embodiment to detect the opening of package200is to provide tabs100constructed out of a material that reacts to ambient air. When package200is opened, tabs100become exposed to the outside air. If tabs100are constructed out of a material that loses its conductivity when exposed to air, transponder10cannot be interrogated and/or communicate as effectively since tabs100are attached to slot300to provide a slot antenna16A for communication. Thus, lack of communication or degraded communication can be used as an indicator that package200has been previously opened.

FIG. 8Billustrates an embodiment where it is not only desirable to place transponder10inside package200, but also to separate transponder10from the contents of package200. In this embodiment, a second seal304is provided in package200. The transponder10is located in first seal306as previously described above. The transponder10is still exposed to air when package200is opened, but transponder10is not contained in the same portion of package200where the contents of package200are contained. This embodiment may be desirable when the contents of package200are food or liquid for consumption, or other materials where it is not safe or desirable for transponder10to come in contact with the contents of package200.

Another embodiment uses sensor20to determine when package200is opened. Sensor20may be any type of sensor that senses elements of air in the area on the outside of package200. Air contains oxygen, nitrogen and other gaseous elements. For instance, sensor20may be an oxygen sensor, including the sensor described in U.S. Pat. No. 6,027,622, entitled “Sensor element,” incorporated herein by reference in its entirety. Further, sensor20can be any type of sensor that senses an environmental factor, such as a gaseous element, that is not contained inside package200when sealed with transponder10therein.

FIG. 9illustrates a flow chart of one embodiment of transponder10using sensor20to determine if package200has been opened. The process starts (block400) and control system12receives signals from sensor20indicating a reading (block402). The control system12determines if reading from sensor20indicates that package200is opened (decision404). If package200is opened, control system102stores this event in memory18to communicate it the next time transponder10is interrogated by interrogation reader50(block406). If transponder10has transmission capability, transponder10may transmit the event of package200being open immediately. The process then ends (block408). Alternatively, if it is determined that the package200is not open (decision404), transponder10takes another reading from sensor (block402), repeating the process again.

FIG. 10illustrates an embodiment of providing transponders10for stamping onto packages200in an assembly line or other manufacturing capacity. A carrier700is provided that contains individual slides702. Carrier700may be a film or other similar type of material. Transponder10is manufactured and placed on carrier700during assembly whereby each portion702contains one transponder10. The carrier700is constructed out of a conductive material. Carrier700may also contain, as part of its construction, one or more conductive tabs100. Since carrier700is a conductive material, tabs100are conductive. Transponder10is placed onto carrier during assembly and connected to tabs100formed in carrier700. Later during the manufacture or assembly process, transponder10is placed onto packages200. Carrier700may have perforations704for movement by a machine in an assembly line when mounting transponders10to portions702. Transponder10, attached to one or more tabs100formed in carrier700, is stamped onto packages200in an assembly line by placing carrier700proximate to packages200. The carrier700is stamped in such a manner that transponder10, with tabs100attached, is placed onto packages200. When desired, a stamping process places carrier700and a particular portion702in contact with package200so that transponder10is more easily attached to package200. The package200may contain slot300, whereby transponder10is stamped across the slot300. Transponder10, tabs100, or both, may also contain an adhesive102, as previously discussed, so that transponder10attaches to package200securely.

FIG. 11Aillustrates a top view of transponder10having an asymmetrical dipole antenna16. An asymmetrical dipole antenna16is an antenna having a first pole different in shape, including, but not necessarily limited to,length, width, volume, and/or density, from the second pole. InFIG. 11A, transponder10is coupled to two conductive tabs10A,10B100A, 100B. The first conductive tab100A is asymmetrical with respect to the second conductive tab10B100B. The twosymmetricalasymmetricaltabs10A100A,100Bcomprisescompriseasymmetrical dipole antenna16.

FIG. 11Billustrates a side view of one embodiment of the transponder10illustrated inFIG. 11A. Tabs100A,100B are placed on a dielectric102. Dielectric102acts as an insulator between tabs100A,100B and substrate202. Dielectric102is a material that is substantially non-conductive. Examples of materials that may be used to form a dielectric102include, but are not limited to: cardboard, plastic, Lexan plastic, fabric, and polypropylene.

If substrate202is constructed out of a conductive material, a separate dielectric102is provided between substrate202and transponder10as illustrated inFIG. 11B. If substrate202is constructed out of a non-conductive material, substrate202may additionally act as dielectric102. In this case, a ground plane (not shown) may be placed on the opposite side of substrate202, so that substrate202, acting as a dielectric102, is in between transponder10and the ground plane. Note that the ground plane may be placed on other places on substrate202and not necessarily on the opposite side from transponder10.

The shape, type, and characteristics of antenna16affect the impedance of transponder10. The substrate202also affects the impedance presented to transponder10by antenna16. This is especially true when a thin dielectric102is used, because there is less insulation between the transponder10/antenna16and substrate202. A thin dielectric102is between approximately 0.1 mm and 2.0 mm. For transponder10to transfer radiation energy from antenna16at the highest radiation level possible without losses, the impedance of the transponder10should be matched to the impedance of antenna16as placed onto substrate202. For example, in one embodiment, the transponder10may have an impedance of 15-j60 ohms. To get optimum transfer of energy between antenna16and transponder10, antenna16, as placed onto substrate202, would need to have a conjugate impedance of transponder10. In practice, impedance matching between transponder10and antenna16does not have to be exact to have energy transfer between transponder10and antenna16necessary for communication. Impedances between transponder10and antenna16that are substantially the same will still allow good energy transfer between antenna16and transponder10.

The transponder10may be used with a variety of different substrates202. To minimize the protrusion of transponder10from substrate202, a thin dielectric102is used. Empirical and modeling data have shown that the operation of an asymmetric antenna16is substantially insensitive to the size and/or dimensions of substrate202when using a dielectric102that is relatively thin. Materials with poorly defined structures and/or dielectric constants, such as cardboard, can be used as dielectric102materials, which also serve as substrate202. This discovery allows antenna16and transponder10impedance to be matched more easily during manufacture without having to take characteristics of substrate202into consideration, such as substrate202size, thickness, and/or dielectric constant. Substrate202does have a certain dielectric constant depending on its material of manufacture and the amount of air present in substrate202. The dielectric constant is the amount of permissivity of a particular material. In addition, antenna16elements, such as tabs100, do not need precise dimensional control, allowing less precise and less expensive materials and methods to be used to define such elements. For example, tabs100may be constructed using label printing techniques and conductive ink, such as described in U.S. Pat. No. 5,566,441, entitled “Attaching an electronic circuit to a substrate,” incorporated herein by reference in its entirety.

In the embodiment illustrated inFIGS. 11A and 11B, asymmetrical tabs10A,100B act as the asymmetrical antenna16. Although the impedance of tabs100A,100B are substantially insensitive to substrate202, tabs100A,100B may be increased or decreased in size, length, and/or width depending on variations in the thickness and dielectric constant of substrate202to provide optimal impedance matching to transponder10.

FIG. 12Aillustrates one modeled example of asymmetrical tabs100A,100B used on a substrate202. Substrate202is a common printed circuit board (PCB) material FR4 with an approximate dielectric constant of 4.65. Two additional tabs101A,101B are added to tabs100A,100B respectively to allow proper modeling and have no effect on results of the asymmetrical antenna16.FIG. 12Billustrates the predicted gain of antenna16, which is −0.85 dBi at 915 MHz.FIG. 12Cillustrates the modeled gain of an asymmetrical antenna16, using tabs100A,100B, on a substrate202having the same dielectric constant as FR4 without losses. The predicted gain for this model is 5.3 dBi at 915 MHz.

As previously stated, tabs100A,100B may vary in size in different manners to provide an asymmetrical antenna16.FIGS. 13,14A and14B illustrate other embodiments of asymmetrical antennas16.FIG. 13illustrates an embodiment of an asymmetrical antenna16, whereby tabs10A,100B are at right angles to each other. One tab100A is substantially thinner than the other tab100B. The performance of the asymmetrical antenna16illustrated inFIG. 13was found to have similar performance characteristics of the asymmetrical antenna16illustrated inFIG. 12A.

FIGS. 14A and 14Billustrate two other embodiments of an asymmetrical antenna16. InFIG. 14A, one tab100B, hereto represented as being thicker than tab100A, is in the shape of a ring, and the other tab100A is nested inside the area bounded by tab100B. This asymmetrical antenna16is almost one-half the total length of the asymmetrical antenna16illustrated inFIG. 12A, and may be used in applications where a shorter asymmetrical antenna16is desired. Similarly,FIG. 14Bdepicts another alternate embodiment of asymmetrical antenna16. In contrast to the embodiment ofFIG. 14A, a relatively thick tab100B is nested within tab100A, which is arranged in the shape of a ring or loop. Again, asymmetrical antenna16inFIG. 14B, is almost one-half the total length of the asymmetrical antenna16illustrated inFIG. 12A, and may be used in applications where a shorter asymmetrical antenna16is desired. For example, a shorter asymmetrical antenna16may be advantageous for design or manufacturing reasons.

FIG. 15Aillustrates another embodiment of an asymmetrical antenna dipole antenna16, whereby substrate202is an aluminum can600. A separate dielectric102is provided between transponder10having tabs100A,100B and can600, because can600is constructed out of a conductive material namely aluminum (as previously discussed). In this particular embodiment, an asymmetrical antenna16is created by using tab100B that is longer in length than tab100A.FIG. 15Billustrates another asymmetrical antenna embodiment, again using a can600as substrate202. Transponder10is placed on the underneath dome602of can600. Two asymmetrical tabs100A,100B are provided to form a dipole antenna16. The resultant dipole antenna16is asymmetrical. Tab100A is shorter in length than tab100B, and tab100B is wider than tab100A.

FIG. 16illustrates another embodiment of an asymmetrical dipole antenna16. In this embodiment, transponder10is placed into an indentation500of substrate202so that transponder10will not protrude from substrate202. Transponder10may be damaged or hit by an outside force if it protrudes from substrate202. Tabs100A,100B are provided on the surface of substrate202on each side of indentation500. Conductive leads502are placed on the inside of indentation500and are electrically coupled to tabs100A,100B. Such coupling may be accomplished by direct connection, capacitive coupling or inductive coupling. Tabs100A,100B are asymmetrical to one another. Transponder10has feed lines504on each side that couple to conductive leads502to couple transponder10and tabs100A,100B together. In this manner, transponder10uses tabs100A,100B to form an asymmetrical dipole antenna16. As illustrated, transponder10has not yet been positioned inside indentation500below the surface level of substrate202. When properly positioned, transponder10does not protrude from the surface of substrate202.

FIG. 17illustrates another embodiment of an asymmetrical antenna16. In this embodiment, the asymmetrical antenna16is provided using a slot300to form an asymmetrical slot antenna16. In this particular embodiment, slot300length is λ/4 and slot300width is 3.625 mm, although other lengths and widths may be used. Transponder10is placed across the slot300using tabs100to form a slot antenna16. The asymmetrical nature of the slot antenna16is controlled by the location of the placement of tabs100across slot300, and not by differences in the size, width, and/or density of tabs100. Tabs100are placed off-center of slot300, thereby forming an asymmetrical slot300. An asymmetrical slot300is a slot that is split into at least two separate portions whereby each portion is of different size, width, and/or depth. If substrate202is constructed out of a conductive material, a separate dielectric102is provided between transponder10and substrate202. If substrate202is constructed out of a non-conductive material, substrate202is dielectric102with a ground plane provided (not shown). Again, this asymmetrical antenna16is substantially insensitive to substrate202when using a thin dielectric102, as previously discussed above.

An alternative embodiment toFIG. 17is to only couple one tab100to transponder10to provide a monopole asymmetric antenna16. Again, tab100is placed off-center across slot300. A ground plane is provided and coupled to transponder10so as to ground transponder10.

The focus of the present invention is on providing wireless communication devices for use on discs, such as compact discs, mini discs, DVDs, and similar devices. Discs may be constructed out of metalized portions that allow storage of digital information. For the purposes of the present claims and the following discussion, some of the terms previously used may be used in a slightly different context.

Turning now toFIG. 18, a particular type of disc known as a compact disc1000is illustrated with wireless communication device1010disposed thereon. Compact disc1000may comprise an outer metalized portion1002upon which data is stored as is conventional, an inner portion1006, typically made from a transparent plastic and delimiting a central hole1008. Non-conductive gap1004exists between outer metalized portion1002and inner portion1006.

Wireless communication device1010, illustrated isolated from compact disc1000inFIG. 19, may comprise a first tab1012, a second tab1014, and a wireless communication chip1016. Wireless communication device1010may be either active or passive as described with reference to U.S. Pat. Nos. 5,347,280 (previously incorporated) and 5,585,953, the latter of which is expressly incorporated by reference.

Tabs1012,1014serve as either a pole antenna or to provide a slot antenna for wireless communication device1010, as discussed below. Tabs1012,1014are a material constructed out of a conductive material, such as metal, copper, or aluminum. Tabs1012,1014may also be in the form of a foil or tape depending on the geometry needs and/or constraints of disc1000.

Wireless communication chip1016may comprise a device from INTERMEC as used in their Intellitag® labels and those devices from SCS as used in their DL100label although other devices are certainly possible, especially in light of the present invention's suitability to both active and passive wireless communication devices1010. Wireless communication chip1016may comprise a control system12, memory18, a battery, a sensor20, and other conventional components.

First tab1012capacitively couples wireless communication chip1016to the outer metalized portion1002to form a first antenna element. The precise dimensions of the first tab1012are dictated in part by the compact disc1000and in part by impedance matching considerations, as previously discussed above. However, also note that first tab1012may be directly connected to outer metalized portion1002to directly connect wireless communication chip1016to outer metalized portion1002.

Second tab1014may be an annulus and is positioned on inner portion1006for form a second antenna element. Second tab1014substantially covers the annulus; however, second tab1014does not cover non-conductive gap1004.

Second tab1014may include a stub1018that extends across gap1004as illustrated inFIG. 18. Wireless communication chip1016may likewise be positioned across gap1004as illustrated.

Gap1004may forms a slot antenna operating at a first frequency for wireless communication device1010. Likewise, tabs1012and1014may form an asymmetric dipole antenna for operation at a second frequency. Exemplary frequencies are 915 MHz and 2.45 GHz. However, the present invention is also applicable to wireless communication chip1016only being coupled to one tab forming a monopole antenna operating at a second frequency.

The relative positioning of wireless communication chip1016with respect to stub1018allows the slot antenna to be formed as an asymmetric slot antenna with first portion1020extending from stub1018to wireless communication chip1016and a second portion1022comprising the other arc between stub1018and wireless communication chip1016.

The size, shape, and placement of stub1018is dictated by impedance matching concerns and the desire for second tab1014to act as an antenna element at the second frequency. For example, while not shown, it is possible to position stub1018opposite wireless communication chip1016so that the slot antenna is not an asymmetrical slot antenna, but rather a normal symmetric dipole slot antenna.

In an exemplary embodiment stub1018is four (4) mm wide and extends the radius of compact disc1000. In this embodiment first tab1012may be ten (10) mm wide and extend the radius of compact disc1000. An arc of thirty-seven degrees separates stub1018from first tab1012. While copper foil is specifically contemplated as being a useful conductor for the construction of first tab1012and second tab1014, other conductive materials such as aluminum are also possible.

Attachment of wireless communication device1010to disc1000may have a variety of useful applications. For instance, wireless communication device1010may provide identification so that disc1000cannot be taken from a retail store without authorization and/or having been purchased. Interrogation reader50may be placed near exit locations in a retail store that sells discs1000, such as a retailer of compact-discs. The flowchart illustrated inFIG. 20discusses the process for detecting the unauthorized removal of disc1000having wireless communication device1010attached.

The process starts (block1050), and interrogation reader50sends out interrogation signal56(block1052) to determine if wireless communication device1010is in range of signal56(decision1054). If there is no detected wireless communication device1010in the range of interrogation reader50, interrogation reader50continues to send out interrogation signal56(block1052). If interrogation reader50detects wireless communication device1010(decision1054), interrogation reader50determines if disc1000was legally purchased (decision1056). If yes, the process start over by interrogation reader50sending out interrogation signal56for subsequent discs1000(block1052). If no, interrogation reader50causes an alert condition (block1058), and the process ends (block1060).

One way for interrogation reader to determine if disc1000was legally purchased or removed from a location with authorization is to interrogate discs1000at exit locations or other desired areas in a store. Interrogation readers50may also be located at points of purchase so that interrogation reader50can mark memory18in wireless communication device1010to indicate a legal purchase. Interrogation reader50, located around exits or other desired locations of store, may then interrogate memory18of wireless communication device1010to determine if disc1000was previously purchased or authorized for removal.

An alert condition may include an audio and/or visual message or signal. For instance, an audio signal may include a siren, alarm, or the like. Such audio signal may be public, or private whereby only certain personnel, such as security personnel, are alerted of the unauthorized removal of disc1000from the retail store. Alert conditions may also include a visual signal, both public and/or private as well.

Wireless communication device1010on disc1000may also cause an interrogation reader50to perform a trigger event in response to identification of disc1000. The identification of disc1000may be stored in memory18of wireless communication device1010in the form of a text or other message.

For instance, it may be desirable to display a visual message to a customer as the customer leaves a retail store with a newly purchased disc1000. If the customer purchases a disc1000that contains an audio recording of a particular artist or musical group, a video display, linked to an interrogation reader50, may display the artist or musical group thanking the customer for his purchase as customer leaves the store. Interrogation reader50determines the identification of disc1000, and causes a trigger event to occur in response thereto. The trigger event may be any type of communication signal, and may be an audio message or combination of video and audio.

The trigger event may also be a coupon issued to the customer for a future purchase. For instance if the customer purchases a disc1000containing jazz music style, interrogation reader50, through associated with a coupon dispensing station, may issue coupons for other jazz music discs1000of the same artist or musical group, or discs1000for other jazz artists or musical groups.

FIG. 21illustrates an interrogation reader50that performs a trigger event in response to a disc1000identification. The process starts (block1080), and interrogation reader50sends out interrogation signal56(block1082). If interrogation reader50does not detect a disc1000in range of interrogation signal56(decision1084), interrogation reader50continues to send out interrogation signal (block1082). If interrogation reader50detects disc1000(decision1084), interrogation reader determines the identification of disc1000(block1086) and performs the appropriate trigger event in response thereto (block1088) before the process ends (block1090). The trigger event may be an event that is external to interrogation reader50, whereby interrogation reader50is coupled to an external device to perform such event. For example, such external device may be a video player that plays when a signal is received from interrogation reader50.

It should be appreciated that while compact disc1000has been discussed in particular, other types of discs, including, but not limited to mini discs, DVDs, and the like are also equally suitable for use with the present invention. This is especially true in light of the uniformity of inner portion1006of a compact disc with comparable inner portions on mini discs and DVDs. Mini discs and DVDs are specifically defined elsewhere in the present application.

Note that the present invention is also well suited for use with a miniature compact disc that is shaped like a business card or in other shapes. Examples of shaped compact discs may be found at http://www.sculptedcd.com/home1.htm and in the document entitled “Sculpted CD, CD Business Card, Admission Ticket, CD-R 3″ Minis,” dated Jan. 4, 2001, incorporated herein by reference in its entirety.

In a non-illustrated embodiment, the wireless communication chip1016and the coupling structure of the tabs1012,1014may be mounted as part of the CD jewel case. The wireless communication chip1016may only be interrogated when the compact disc1000is inserted into the jewel case and the case is closed bringing the chip1016and the tabs1012,1014into close proximity to the elements that act as the antenna.

Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. It should be understood that the present invention is not limited to any particular type of wireless communication device, tabs, disc, packaging, or slot arrangement. For the purposes of this application, couple, coupled, or coupling is defined as either directly connecting or reactive coupling. Reactive coupling is defined as either capacitive or inductive coupling. The present invention is intended to cover what is claimed and any equivalents. The specific embodiments used herein are to aid in the understanding of the present invention, and should not be used to limit the scope of the invention in a manner narrower than the claims and their equivalents.