A method of manufacturing RFID devices

Abstract

A method and system for manufacturing an RFID device involve positioning a first conductive member relative to a second conductive member and temporarily securing them together. A localized temperature increase is created at an interface between the conductive members, forming a galvanic connection at a localized weld zone. The method may include applying pressure during heating and can use various heating techniques such as inductive, capacitive discharge, or laser heating. The system includes a transporter, a positioner, and an energy applicator. An RFID device manufactured by this method comprises a first conductive member, a second conductive member, and a galvanic connection between them, with the connection having a localized weld zone exhibiting distinct structural characteristics. The method and system may improve electrical connectivity in RFID devices, particularly between RFID straps and antennas.

Description

A METHOD OF MANUFACTURING RFID DEVICESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of U.S. Provisional Patent Application No 63 / 661,697 filed June 19, 2024, the entirety of which is incorporated herein by reference.FIELD OF THE INVENTION

[0002] The present subject matter relates to radio frequency identification (RFID) devices and a method of manufacturing such devices.BACKGROUND

[0003] Radio frequency identification (RFID) devices are widely used for automatic and contactless identification of objects, products, packaging, items of merchandise, and living beings using radio waves. RFID devices include an integrated circuit, or "chip." and an antenna, with the chip being operatively coupled to the antenna. The antenna is generally a metallic conductor that enables the reception and emission of radio waves in an electromagnetic field. The chip contains memory that stores the product's identity such as an electronic product code and other valuable information. The antenna enables the integrated circuit or chip to send identification information to an RFID reader.

[0004] Due to the significant variance in the dimensions of the antenna and the chip, direct attachment of the chip with the antenna during high-speed chip assembly is difficult. Typically, the contacts of the chips need to be precisely positioned on the contact positions of the antenna before a bonding process is performed to form a permanent electrical connection between the contacts of the chip and the antenna, thereby forming an RFID device known as a direct inlay. However, because the dimensions of the RFID chip and its contacts are extremely small compared to the dimensions of the antenna, the process of aligning the chip contacts to antenna contacts is slow and tedious, requiring an extremely high level of precision for appropriate and robust connection between the antenna and the chip. Appropriate coupling isone of the single most important factors determining performance of the RFID device, such as the ability of the RFID device to receive or transmit RF waves appropriately, and the range of readability of the RF device.

[0005] In order to overcome the difficulties associated with direct assembly of chips on antennas, connection structures known as "straps" or "interposers" were devised. Straps include conductive leads or pads that are electrically coupled to the contact pads of the chips for coupling to the antennas. These pads provide a larger effective electrical contact area than chips alone, which need precise alignment when directly placed on an antenna without a strap. The larger area of the strap reduces the accuracy and precision required for the placement of chips during the RFID device manufacturing process while still providing an effective electrical connection.

[0006] Conventionally, the strap is capacitively coupled to the antenna through an intervening dielectric layer. The dielectric layer prevents direct conductive contact between portions of the strap, such as the strap leads and the antenna. A trade off of this approach is that this type of connection results in lower sensitivity as compared to a direct chip attach inlay, thereby affecting the RF performance of the RFID device.

[0007] Further, it must be noted that an adhesive is often used to create a capacitive coupling between the chip and the antenna. This adhesive acts as a dielectric material between the conductive surfaces. However, dielectric materials inherently cause some energy loss when an electromagnetic field passes through them. This dielectric loss reduces the overall efficiency of the RFID device, potentially decreasing its read range and performance.

[0008] Further, the size of the bond pads or contact pads in the antenna geometry plays a crucial role in the overall performance of the RFID device. In small RFID devices, where space is at a premium, the impact of these bond pads becomes even more pronounced. The central loop of the antenna, which is key to its operation, can be compromised by the presence of large metal blocks used for bonding pads. These metal blocks create a form of parasitic coupling, which is an unintended interaction between the antenna and its surrounding environment. This parasitic coupling occurs because the large metal areas of the bond pads interact with the electromagnetic field in ways that are not optimal for the antenna's designedperformance. The effect is particularly detrimental in the immediate area surrounding the chip, where the coupling between the antenna and the materials to which it is attached is most critical. This suboptimal coupling can lead to a reduction in the tag's sensitivity, with estimated losses ranging from 1 to 1.5 decibels (dB), depending on the specific antenna design. Such a loss in sensitivity can significantly impact the RFID device's read range and overall performance, especially in applications where maximum efficiency is required. The challenge, therefore, lies in designing bond pads of the strap that are large enough to ensure a reliable connection between the chip and the antenna, while minimizing their impact on the antenna's electromagnetic properties, particularly in the critical central loop area of small RFID tags.

[0009] Further, existing methods for creating electrical connections in RFID devices often employ low-temperature heating techniques to avoid damaging sensitive Integrated Circuits (ICs). However, these low-temperature approaches can significantly restrict the choice of conductive materials that can be effectively bonded. The constraints on material choice may restrict design options for antennas and other conductive components, potentially limiting the ability to optimize RFID device performance for specific applications or environments.

[0010] There is a long-standing need for an improved RFID device, and a method and system for manufacturing RFID devices that can overcome the aforementioned limitations and challenges.SUMMARY

[0011] The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed innovation. This summary is not an extensive overview, and it is not intended to identify key or critical elements or to delineate the scope thereof. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

[0012] RFID devices and methods of their manufacture are disclosed. An exemplary RFID device comprises a web of substrate carrying a second conductive member, such as an antenna with antenna contacts, and a first conductive member, such as a strap carrying an RFID chip and having two extended contacting portions for a physical and electrically conductive connection with the antenna. The physical and electrically conductive connection between thefirst conductive member and the second conductive member is established by passing current to generate heat between the contacting portions of the first conductive member and the corresponding contacting portions of the second conductive member.

[0013] In some embodiments, a method of a method of manufacturing an RFID device is provided. The method includes positioning a first conductive member relative to a second conductive member and temporarily securing the first conductive member to the second conductive member. The method further involves creating a localized temperature increase at an interface between the first and second conductive members while at least one of the conductive members is in motion. In response to the localized temperature increase, a galvanic connection is formed between the first conductive member and the second conductive member at a localized weld zone at the interface.

[0014] In some embodiments, a system for manufacturing a radio frequency identification (RFID) device, is disclosed. The system may include a transporter configured to move at least one of a first conductive member or second conductive member. Further, the system may further include a positioner configured to position the first conductive member relative to the second conductive member and temporarily secure the first conductive member to the second conductive member. The system may further include an energy applicator configured to create a localized temperature increase at a localized weld zone at an interface between the first and second conductive members to form a galvanic connection while at least one of the conductive members is in motion.

[0015] In some embodiments, a method of improving electrical connectivity in an RFID device is disclosed. The method includes aligning a first conductive member with a second conductive member on a moving substrate. The method may further include applying energy to create a localized temperature increase at an interface between the first and second conductive members. In response to the localized temperature increase, a direct electrical pathway is established at a localized weld zone at the interface between the first and second conductive members.

[0016] In some embodiments, an RFID device is disclosed. The RFID device includes a first conductive member and a second conductive member, with a galvanic connection betweenthe first and second conductive members. The galvanic connection comprises a localized weld zone at an interface between the first and second conductive members, the localized weld zone having structural characteristics distinct from adjacent non-welded areas of the first and second conductive members.BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 illustrates a system for manufacturing an RFID device, according to an embodiment.

[0018] Fig. 2 illustrates an implementation of an inductive heating subsystem, according to an embodiment.

[0019] Fig. 3 illustrates an implementation of a capacitive discharge heating subsystem, according to an embodiment.

[0020] Fig. 4A illustrates positioning of two electrodes of the capacitive discharge welding subsystem, in accordance with a first exemplary embodiment.

[0021] Fig. 4B illustrates positioning of two electrodes in the capacitive discharge welding subsystem, in accordance with a second exemplary embodiment.

[0022] Fig. 4C illustrates positioning of two electrodes in the capacitive discharge welding subsystem, in accordance with a third exemplary embodiment.

[0023] Fig. 5 illustrates a flowchart of a method for manufacturing an RFID device, in accordance with an embodiment.

[0024] Fig. 6 illustrates a flowchart of a method of establishing electrical connectivity in RFID device.DETAILED DESCRIPTION

[0025] The innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding thereof. It may be evident, however, that the present subject matter can bepracticed without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate a description thereof.

[0026] The present disclosure describes various embodiments of a system and a method for manufacturing of radio-frequency identification device.

[0027] In some embodiments, the system for manufacturing an RFID device is disclosed. The system includes a transporter, a positioner, and an energy applicator.

[0028] Referring to Fig. 1 illustrates the system 100 for manufacturing the RFID device. The system comprises a transporter, which is configured to move at least one of a first conductive member or a second conductive member. The transport system may involve, for example, a continuously moving web, conveyor system, or other means of transporting the conductive members through the manufacturing process. As shown in Fig. 1, a web of substrate 101 with a plurality of second conductive members 102 of the RFID device secured thereto is disposed on the reel 110. In the present embodiment, the second conductive member 102 is an antenna of the RFID device. The web of substrate 101 with the plurality of second conductive members 102 is unwound from the reel 110 by any suitable transporter such that it travels from left to right, as viewed in Fig. 1.

[0029] In some embodiments, the first conductive member 103, such as an RFID strap, is unwound from the roll of RFID straps supplied on a continuous web of substrate 101 by any suitable transporter.

[0030] In some embodiments, the web of substrate 101 is a conventional material, for example, polymeric (e.g., PET) material, cellulose-based materials (e.g., paper, fabric), etc. In some embodiments, the first conductive member 103 is an RFID strap or an interposer. The RFID strap comprises a central portion for mounting an RFID chip and two extended contacting portions extending outward from the central portion to form a galvanic connection with the antenna. The antenna may be a dipole, loop, or other type of RFID antenna that comprises contact pads.

[0031] In some embodiments, the antenna may be formed from any conductor with suitable properties, such as aluminum or a conductive printed ink containing, for example, aluminum, copper, or the like. The thickness of the antenna may vary based on the intended useof the RFID device. In some embodiments, the antenna and the RFID strap may be made of the same material, such as both being made of aluminum.

[0032] In some embodiments, the system 100 comprises a positioner (not shown in the figures) to position the first conductive member 103 relative to the second conductive member 102. The positioner may also temporarily secure the first conductive member 103 to the second conductive member 102. The positioner comprises a temporary attachment mechanism configured to hold the first conductive member 103 in proximity to the second conductive member 102. The temporary attachment mechanism, such as an applicator 111, is configured to apply an adhering material between the first conductive member 103 and the second conductive member 102. In some embodiments, the adhering material is applied over the second conductive member 102, such as the antenna, and then the first conductive member 103, such as the RFID strap, is attached over the adhering material using the RFID strap dispenser. In some embodiments, the adhering material is applied in a shape or a pattern that is desired for the antenna configuration. In some embodiments, the adhering material is applied in the shape of an antenna's contact pads.

[0033] In some embodiments, the adhering material is applied over the first conductive member 103, moving on the web of substrate 101, and then the second conductive member 102, such as an antenna, is attached over the adhering material. In some embodiments, the adhering material is applied in a shape or a pattern of two extended contacting portions of the RFID strap.

[0034] In some embodiments, the first conductive member 103 and the second conductive member 103 are in motion on a continuously moving web of substrate 101.

[0035] In some embodiments, the first conductive member 103 is in motion on a continuously moving web of substrate 101.

[0036] In some embodiments, the second conductive member 102 is in motion on continuously moving web of substrate 101.

[0037] In some embodiments, a RFID strap dispenser unwinds the roll of the RFID strap supplied on a continuous web or sheet of the RFID strap by any suitable transporter. The RFID strap dispenser is configured to separate or singulate individual RFID straps from thecontinuous web or sheet of RFID straps, and then apply them over the second conductive material 102, which is in motion on a continuously moving web of substrate 101.

[0038] In some embodiments, the singulated first conductive members are transferred to a vacuum anvil in a manner such that the adhering material coated on the strap faces outward. In some embodiments, a tamping tool is used to push the web of substrate carrying the antenna upwards, before the strap is attached along with the adhering material to the antenna.

[0039] In some embodiments, the adhering material comprises at least one of an adhesive, a wax, a conductive flux, a non-conductive flux, a tacky substance, a pressure-sensitive material, or a bonding agent. The adhesive is either an ultraviolet curable adhesive, a pressure sensitive adhesive, a non-conductive adhesive, or a conductive adhesive.

[0040] Further, the system 100 comprises an energy applicator to create a localized temperature increase at a "localized weld zone", at the interface between the first conductive member 103 and second conductive members 102. The localized weld zone is located on at two extended contacting portions of the strap and contact pads of the antenna. In one exemplary embodiment, antenna is the dipole antenna.

[0041] In some embodiments, the localized temperature increase occurs while the first conductive member 103 and the second conductive member 103 are in motion on a continuously moving web of substrate 101.

[0042] The localized temperature increase forms a galvanic connection at the localized weld zone between the first conductive member 103 and the second conductive member 102. In an exemplary embodiment, each first conductive member 103 attached to each corresponding second conductive member 102 on the moving web of the substrate 101 is subjected to a punctual rise in temperature. In some embodiments, the variables are defined to deliver enough energy to heat the conductive materials of the antenna and the strap past their melting points. Subsequently, the web of substrate 101 is subjected to a conversion using rollers 114a and 114b, followed by die cutting using die-cutting tools 115. Inspection of the RFID devices being carried out using an inspection device 116, before the substrate is rewound using a rewinding reel 117. The conversion involves unwinding a layer of face stock using a first roller114a over the top surface of the web of the substrate and unwinding a layer of release liner on the bottom surface of the web of the substrate using a second roller 114b. As noted above, in some embodiments, the conversion is optional. In such embodiments, the conversion may be performed independently in a separate line of production.

[0043] As shown in Fig. 1, the energy applicator such as welding subsystem 113 is used to perform localized temperature increase at the localized weld zone. The energy applicator is at least one of an inductive heating subsystem, a capacitive discharge heating subsystem or a laser welding subsystem, to create the localized temperature increase. The energy applicator is designed to focus the energy precisely at the localized weld zone at the interface between the temporarily secured first and second conductive members.

[0044] Fig. 2 illustrates an inductive heating subsystem 200, in accordance with one embodiment. The inductive heating subsystem 200 comprises an electrically conductive material / workpiece in the shape of a coil 210, such as copper coil and an inductive heat control unit 211. In some embodiments, various coil designs are employed to help focus heat to particular parts of the conductive members being welded. These specialized coil designs allow for more precise control over the heating process, ensuring that energy is concentrated where it is most needed for effective welding. For example, longer coil designs may be used to increase dwell time at high speeds, allowing for more consistent heating even as the web moves rapidly through the inductive heating subsystem 200. The inductive heating subsystem 200 is configured to generate an electromagnetic field. The inductive heat control unit 211 is configured to control the generation of the electromagnetic field to induce eddy currents at the interface of the first conductive member 103 and the second conductive member 102. In some embodiments, and as shown in Fig. 2, the passage of current through the coil 210 is controlled by an inductive heat control unit 211 based on inputs received from an inductive proximity sensor 212. The inductive proximity sensor 212 is configured to detect the presence of the first member 103 on the second member 102. In some embodiments, the inductive proximity sensor 212 is positioned in a stage succeeding the stage of temporary attachment is performed. In some embodiments, the inductive heat control unit 211 and the coil 210 are positioned in a stage succeeding the inductive proximity sensor 212.

[0045] In one exemplary embodiment, the inductive heating subsystem is configured to create a galvanic connection in 15-25 milliseconds. In some embodiments, the passage of current through the coil 210 is controlled in a manner so that the contacting portions of the first conductive member 103 and the second conductive member 102 are heated for approximately 15-25 milliseconds. In some embodiments, the coil 210 is water-cooled to control its temperature. In an exemplary embodiment, the movement of the web 101 carrying the first conductive member 103 temporarily attached to the second conductive member 102 is not halted for completing the required heating. In some embodiments, the movement of the web 101 may be stopped for 15-25 milliseconds during the passage of current. The passage of current through the coil 210 facilitates the formation of a physical and electrically conductive connection between the first conductive member 103 and the second conductive member 102 of the RFID device. In other words, the galvanic connection is created between the first conductive member 103 and the second conductive member 102 of the RFID device. In some embodiments, simultaneous pressure may be applied to establish the galvanic connection. Once the galvanic connection is complete, the web of substrate 101 carrying the first conductive member 103 welded to the second conductive member 102 moves to the next stage of production.

[0046] In one exemplary embodiment, the conductive material for the antenna and / or strap is aluminum. The melting point of aluminum is approximately 660 degrees Celsius. Therefore, the welding temperature is controlled in the range of 660-700 degrees Celsius. By controlling the welding temperature within this range, the welding ensures that the aluminum components reach their melting point and form a strong, reliable connection without excessive heating that could damage surrounding materials or components. The precise control of temperature in this range allows for optimal bonding between the aluminum elements while minimizing the risk of thermal damage to the RFID chip or substrate materials.

[0047] In one exemplary embodiment, the inductive heating subsystem includes a frequency range of the AC magnetic field of 700 kHz, an input power range of 2.1 kVA, and an output power range of 2kW. Further, input / output current is 40mA.

[0048] In some embodiments, soft magnetic composites (SMCs) may be used to concentrate the electromagnetic field generated by the coil in order to direct heat to thecontacting portions of the first conductive member 103 and the second conductive member 102 of the RFID device.

[0049] In some embodiments, the energy applicator is a capacitive discharge welding subsystem. Fig. 3 illustrates the capacitive discharge welding subsystem 300, in accordance with an embodiment. In some embodiments, the capacitive discharge heating subsystem comprises a bank of capacitors and a control unit. The bank of capacitors is configured to store electrical energy. The control unit is configured to release the stored electrical energy in a series of timed pulses. In some embodiments, the capacitive discharge heating subsystem comprises two electrodes configured to be positioned relative to the first conductive member 103 and the second conductive member 103 and pass current through the first conductive member 103 and the second conductive member 102 to form the galvanic connection at the interface between the first conductive member 103 and the second conductive member 102.

[0050] As shown in Fig. 3, a high current is passed through the first conductive member 103 and the second conductive member 102 of the RFID device with the aid of a device 301, such as a strap welder to form the galvanic connection between the first conductive member 103 and the second conductive member 102. The device 301 is configured to create a spot weld 105 to form galvanic connection at the localized weld zone between the first conductive member 103 and the second conductive member 102 of the RFID device.

[0051] In some embodiments, the spot weld is created by passing a high current through two layers of the RFID device, such as the layer of the first conductive member 103 and the layer of the second conductive member 102, by means of two electrodes.

[0052] Figs 4A-4C illustrate various exemplary embodiments depicting different positions of the two electrodes on the layers of the RFID device.

[0053] In a first exemplary embodiment, the two electrodes are configured to be placed over the first conductive member 103. Fig. 4A illustrates the positioning of two electrodes of the capacitive discharge heating subsystem, in accordance with the first exemplary embodiment. Both the electrodes 401 used for welding are placed over the first conductive member 103 of the RFID device.

[0054] In a second exemplary embodiment, the two electrodes are configured such that one electrode 401 is positioned above the first conductive member 103, and the other electrode 401 is positioned below the second conductive member 102. Fig. 4B illustrates the positioning of two electrodes in the capacitive discharge heating subsystem, in accordance with the second exemplary embodiment.

[0055] In a third exemplary embodiment, the two electrodes are configured such that one electrode 401 is positioned above the first conductive member and the other electrode 401 is positioned adjacent to the first conductive member 103 and contacting a top surface of the second conductive member 102. Fig. 4C illustrates the positioning of two electrodes in the capacitive discharge heating subsystem, in accordance with a third exemplary embodiment.

[0056] In some embodiments, the capacitive discharge heating subsystem is configured to create a conductive pathway through non-conductive portions of at least one of the first conductive member 103 or the second conductive member 102.

[0057] As shown in Fig. 4A-4C, the arrows show the current pathway created by the electrodes 401 to create a gap (not shown) between the non-conductive portion 103a, which acts as a strap liner, and the non-conductive portion 102a, which acts as an antenna liner.

[0058] In one embodiment, the capacitive discharge heating subsystem is configured to create the conductive pathway by burning a gap through an insulating layer using a high- voltage arc.

[0059] In another embodiments, the capacitive discharge heating subsystem is configured to create the conductive pathway by removing a region of insulating material in a preceding process.

[0060] In yet another embodiment, the capacitive discharge heating subsystem is configured to create conductive pathway by mechanically piercing a layer using a sharp object, such as a needle or probe, to create a small hole through which electrical contact can be made.

[0061] In some embodiments, the laser heating subsystem comprises a laser and a beam directing system. The laser is configured to generate laser beams. The beam directing system is configured to direct the laser beams onto the first conductive member 103 and the second conductive member 102. In some embodiments, a CO2 laser may be utilized for forminga galvanic connection between the first conductive member and the second conductive member made up of aluminum material, due to its effectiveness.

[0062] In some embodiments, an Nd:YAG laser may be used to form a galvanic connection between the first conductive member and the second conductive member. The laser beam is highly focused and applied for a specific duration to act as a precise heat source, melting and fusing the materials at the desired contact portions of the first conductive member and the second conductive member. This laser welding approach offers several advantages in RFID device manufacturing. It can significantly increase the speed and precision of the welding process, allowing for rapid and accurate connections between the antenna and strap components. Additionally, the laser heating subsystem tends to produce galvanic connections with minimal defects, resulting in higher quality and more reliable connections. The highly localized heating provided by the laser beam also minimizes thermal impact on surrounding areas, which is particularly beneficial when working with heat-sensitive RFID components.

[0063] Fig. 5 illustrates a flowchart of a method for manufacturing an RFID device, in accordance with an embodiment.

[0064] At step 502, the first conductive member 103 is positioned relative to the second conductive member 102. Then the first conductive member 103 is temporarily secured to the second conductive member 102. In some embodiments, temporarily securing the first conductive member 103 to the second conductive member 102 includes applying the adhering material between the first conductive member and the second conductive member.

[0065] At step 504, the localized temperature increase is created at the interface between the first conductive member and the second conductive member. The method 500 further comprises a step for simultaneously applying pressure on the localized weld zone when the localized temperature increase is created at the interface between the first conductive member and the second conductive member. In some embodiments, pressure is applied using a mechanical roller or clamp. The localized temperature increase is created using at least one of an inductive heating, a capacitive discharge heating or a laser heating.

[0066] In some embodiments, the inductive heating is performed using a coil positioned in proximity to the first and second conductive members. The inductive heatingcomprises inducing eddy currents at the interface between the first and second conductive members using an electromagnetic field generated by the coil.

[0067] Further, the inductive heating is controlled based on an input from a proximity sensor configured to detect the presence of the first conductive member on the second conductive member. The interface of the first member and the second member of the RFID device is heated by the eddy currents for 15-25 ms.

[0068] In some embodiments, the localized temperature increase is created at the interface between the first conductive member and the second conductive member by capacitive discharge heating. The capacitive discharge heating is performed by positioning two electrodes in a configuration relative to the first conductive member and the second conductive member.

[0069] In some embodiments, the capacitive discharge heating is performed by passing current through the first conductive member and the second conductive member using the two electrodes to form the galvanic connection at the interface between the first conductive member and the second conductive member.

[0070] In some embodiments, the capacitive discharge heating is performed by positioning both electrodes over the first conductive member.

[0071] In some embodiments, the capacitive discharge heating is performed by positioning one electrode above the first conductive member and the other electrode below the second conductive member.

[0072] In some embodiments, the capacitive discharge heating is performed by positioning one electrode above the first conductive member and the other electrode adjacent to the first conductive member and contacting the top surface of the second conductive member.

[0073] In some embodiments, the localized temperature increase is created at the interface between the first conductive member and the second conductive member by laser heating. The laser heating comprises impinging laser beams on the first conductive member and the second conductive member.

[0074] At step 506, the galvanic connection between the first conductive member 103 and the second conductive member 102 is formed at the localized weld zone at the interface in response to the localized temperature increase. In some embodiments, the localized weld zoneis located on two extended contacting portions of the RFID strap and contact pads of the dipole antenna.

[0075] Fig. 6 illustrates a flowchart of a method of establishing electrical connectivity in an RFID device.

[0076] At step 602, the first conductive member 102 is aligned with a second conductive member 103 on a moving substrate or web.

[0077] At step 604, a localized temperature increase is created at the interface between the first conductive member 103 and the second conductive member 102.

[0078] At step 606, a direct electrical pathway at the localized weld zone at the interface is established between the first and second conductive members in response to the localized temperature increase. In some embodiments, the localized weld zone is located on two extended contacting portions of the RFID strap and contact pads of the dipole antenna.

[0079] In some aspects, an improved RFID device is disclosed. The RFID device comprises a first conductive member and a second conductive member joined by a galvanic connection.

[0080] In some embodiments, the first conductive member may be the RFID strap, while the second conductive member may be the antenna. The RFID device may comprise a substrate supporting at least one of the first or second conductive members. The galvanic connection between the first and second conductive members is characterized by the localized weld zone at the interface of the first and second conductive members.

[0081] The localized weld zone is located on two extended contacting portions of the strap and contact pads of the dipole antenna. This localized weld zone exhibits structural characteristics that are distinct from the adjacent non-welded areas of both the first and second conductive members.

[0082] The localized weld zone may be formed through a controlled application of energy, such as heat, resulting in an electrically conductive bond between the two conductive members.

[0083] In some embodiments, the localized weld zone exhibits a microstructure characteristic of localized heating and cooling.

[0084] The localized weld zone allows for a secure connection without exposing heatsensitive components, such as the RFID chip, to potentially damaging temperatures. This is particularly advantageous in maintaining the integrity and functionality of the RFID device.

[0085] In some embodiments, the method of manufacturing the RFID device by creating a physical and electrically conductive connection between the first member and the second member of the RFID device may offer several significant advantages. The direct galvanic connection may eliminate the dielectric layer typically present in adhesive-based connections, potentially removing associated dielectric losses. This elimination of dielectric loss may result in improved RF performance, potentially increasing the read range and sensitivity of the RFID device.

[0086] Furthermore, the galvanic connection may allow for a substantial reduction in the size of bond pads on both the antenna and the RFID strap. This miniaturization may lead to improved antenna performance, particularly in small RFID tags, by reducing parasitic coupling effects in the critical central loop area. The smaller bond pads may enable more compact antenna designs, potentially allowing for the creation of smaller RFID tags or tags with more complex antenna geometries. In some cases, this reduction in bond pad size may also result in material savings, potentially lowering production costs.

[0087] Furthermore, the galvanic connection at the localized weld zone at the interface between the first and second conductive members may provide several benefits in the manufacturing process. An advantage of this localized heating approach is the ability to form a galvanic connection without risking damage to sensitive components, particularly the RFID chip. By concentrating the temperature increase in a specific, limited area, the system minimizes heat exposure to surrounding regions of the RFID device.

[0088] Additionally, the localized weld zone provides flexibility to work with a wide range of materials, including those with high temperature-bearing properties. This versatility allows manufacturers to select materials based on other desirable characteristics such as durability, cost-effectiveness, or specific electrical properties, without being constrained by low melting points or heat sensitivity. The precise control over the heating area enables the use ofmaterials that require higher temperatures for effective bonding, while still protecting surrounding components and substrates from heat damage.

[0089] The conductive connection technique may be applied to a wide range of RFID designs and form factors, offering flexibility in product development and customization. Additionally, direct conductive connections may offer improved long-term reliability compared to adhesive-based connections, potentially extending the operational lifespan of RFID devices. By addressing key limitations of traditional RFID manufacturing methods, this approach may enable the production of high-performance RFID devices that are more efficient, compact, and cost-effective, while maintaining the benefits of large-scale manufacturing processes. These advantages may collectively contribute to the overall improvement in RFID device performance and manufacturability.

[0090] What has been described above includes examples of the claimed subject matter. It may be, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art may recognize that many further combinations and permutations of the claimed subject matter are possible. Accordingly, the claimed subject matter may be intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim.

Claims

CLAIMSWhat is claimed is:

1. A method of manufacturing an RFID device, the method comprising: positioning a first conductive member relative to a second conductive member and temporarily securing the first conductive member to the second conductive member; creating a localized temperature increase at an interface between the first and second conductive members; and forming a galvanic connection between the first conductive member and the second conductive member at a localized weld zone at the interface in response to the localized temperature increase.

2. The method of claim 1, wherein temporarily securing the first conductive member to the second conductive member comprises applying an adhering material between the first conductive member and the second conductive member.

3. The method of claim 2, wherein the adhering material comprises at least one of an adhesive, a wax, a conductive flux, a non-conductive flux, a tacky substance, a pressure-sensitive material, or a bonding agent.

4. The method of claim 3, wherein the adhesive is either an ultraviolet curable adhesive, a pressure-sensitive adhesive, a non-conductive adhesive, or a conductive adhesive.

5. The method of claim 1, further comprising applying pressure on the localized weld zone when the localized temperature increase is created at the interface between the first conductive member and second conductive member.

6. The method of claim 1, wherein the first conductive member includes a RFID strap and the second conductive member includes an antenna.

7. The method of claim 6, wherein the antenna is a dipole antenna comprising contact pads.

8. The method of claim 6, wherein the RFID strap comprising: a central portion for mounting an RFID chip; and two extended contacting portions extending outward from the central portion for a physical and electrically conductive connection with the antenna.

9. The method of claim 1, wherein the localized weld zone is located on at two extended contacting portions of the RFID strap and contact pads of the dipole antenna.

10. The method of claim 1, wherein creating the localized temperature increase is at least one of an inductive heating, a capacitive discharge heating or a laser heating.

11. The method of claim 10, the inductive heating is performed using a coil positioned in proximity to the first and second conductive members, wherein the inductive heating comprises inducing eddy currents at the interface between the first and second conductive members using an electromagnetic field generated by the coil.

12. The method of claim 11, further comprising controlling the inductive heating based on an input from a proximity sensor configured to detect the presence of the first conductive member on the second conductive member.

13. The method of claim 11, wherein the interface of the first member and the second member of the RFID device is heated by the eddy currents for 15-25 ms.

14. The method of claim 10, wherein the capacitive discharge heating is performed by: positioning two electrodes in a configuration relative to the first conductive member and the second conductive member; and passing current through the first conductive member and the second conductive member using the two electrodes to form the galvanic connection at the interface between the first conductive member and the second conductive member.

15. The method of claim 14, wherein positioning the two electrodes comprises placing both electrodes over the first conductive member.

16. The method of claim 14, wherein positioning the two electrodes comprises positioning one electrode above the first conductive member and other electrode below the second conductive member.

17. The method of claim 14, wherein positioning one electrode above the first conductive member and other electrode adjacent to the first conductive member and contacting a top surface of the second conductive member.

18. The method of claim 10, wherein laser heating comprises impinging laser beams over the first conductive member and the second conductive member.

19. The method of claim 1, wherein at least one of the conductive members is in motion on a continuously moving web of substrate.

20. The method of claim 1, further comprising cutting the web of substrate to separate individual RFID devices after forming the galvanic connection.

21. A system for manufacturing a radio frequency identification (RFID) device, comprising: a transporter configured to move at least one of a first conductive member or second conductive member; a positioner configured to position the first conductive member relative to the second conductive member and temporarily secure the first conductive member to the second conductive member; and an energy applicator configured to create a localized temperature increase at a localized weld zone at an interface between the first and second conductive members to form a galvanic connection.

22. The system of claim 21, wherein the positioner comprises a temporary attachment mechanism configured to hold the first conductive member in proximity to the second conductive member.

23. The system of claim 22, wherein the temporary attachment mechanism is configured to apply an adhering material between the first conductive member and the second conductive member.

24. The system of claim 23, wherein the adhering material comprises at least one of an adhesive, a wax, a conductive flux, a non-conductive flux, a tacky substance, a pressure-sensitive material, or a bonding agent.

25. The system of claim 24, wherein the adhesive is either an ultraviolet curable adhesive, a pressure-sensitive adhesive, a non-conductive adhesive, or a conductive adhesive.

26. The system of claim 20, wherein the first conductive member comprises an electrically conductive strap that carries an RFID chip and the second conductive member comprises an antenna.

27. The system of claim 20, wherein the energy applicator is at least one of an inductive heating subsystem, a capacitive discharge heating subsystem or a laser heating subsystem.

28. The system of claim 27, wherein the inductive heating subsystem comprises: an electrically conductive material / workpiece configured to generate an electromagnetic field; and an inductive heat control unit configured to control the generation of the electromagnetic field to induce eddy currents at the interface of the first conductive member and the second conductive member.

29. The system of claim 28, wherein the inductive heating subsystem is configured to create the galvanic connection in 15-25 milliseconds.

30. The system of claim 27, wherein the capacitive discharge heating subsystem comprises: a bank of capacitors configured to store electrical energy; and a control unit configured to release the stored electrical energy in a series of timed pulses.

31. The system of claim 27, wherein the capacitive discharge heating subsystem comprises two electrodes configured to be positioned relative to the first conductive member and the second conductive member and pass current through the first conductive member and the second conductive member to form a galvanic connection at the interface between the first conductive member and the second conductive member.

32. The system of claim 31, wherein the two electrodes are configured to be placed over the first conductive member.

33. The system of claim 31, wherein the two electrodes are configured such that a first of the two electrodes is positioned above the first conductive member and a second of the two electrodes is positioned below the second conductive member.

34. The system of claim 31, wherein the two electrodes are configured such that a first of the two electrodes is positioned above the first conductive member and a second of the two electrodes is positioned adjacent to the first conductive member and contacting a top surface of the second conductive member.

35. The system of claim 27, the capacitive discharge heating subsystem is configured to create a conductive pathway through non-conductive portions of at least one of the first conductive member or the second conductive member.

36. The system of claim 35, wherein the capacitive discharge heating subsystem is configured to create the conductive pathway by at least one of: burning a gap through an insulating layer with a high-voltage arc; removing a region of insulating material in a preceding process; or mechanically piercing a layer using a sharp object.

37. The system of claim 27, wherein the laser heating subsystem comprises a laser configured to generate laser beams; and a beam directing system configured to impinge the laser beams over the first conductive member and the second conductive member.

38. The system of claim 21, wherein the transporter comprises a web transporter configured to continuously move a web of substrate.

39. The system of claim 21, further comprising a cutting mechanism configured to separate individual RFID devices.

40. The system of claim 21, wherein the first conductive member includes an RFID strap a strap and the second conductive member includes an antenna.

41. The system of claim 22, wherein the antenna is a dipole antenna comprising contact pads.

42. The system of claim 40, wherein the RFID strap comprising: a central portion for mounting an RFID chip; and two extended contacting portions extending outward from the central portion to form the galvanic connection with the antenna.

43. The system of claim 21, wherein the localized weld zone is located on at two extended contacting portions of the strap and contact pads of the dipole antenna.

44. A method of improving an electrical connectivity in an RFID device, comprising: aligning a first conductive member with a second conductive member on a moving substrate;applying energy to create a localized temperature increase at an interface between the first and second conductive members; and establishing a direct electrical pathway at a localized weld zone at the interface between the first and second conductive members in response to the localized temperature increase.

45. The method of claim 44, wherein the first conductive member comprises a RFID strap and the second conductive member comprises an antenna.

46. The method of claim 45, wherein the antenna is a dipole antenna comprising contact pads.

47. The method of claim 46, wherein the RFID strap comprising: a central portion for mounting an RFID chip; and two extended contacting portions extending outward from the central portion to form the galvanic connection with the antenna.

48. The system of claim 44, wherein the localized weld zone is located on at two extended contacting portions of the strap and contact pads of the dipole antenna.

49. The method of claim 44, wherein applying energy comprises at least one of an inductive heating, a capacitive discharge heating, or a laser heating.

50. An RFID device, comprising: a first conductive member; a second conductive member; a galvanic connection between the first and second conductive members, wherein the galvanic connection comprises a localized weld zone at an interface between the first and second conductive members, the localized weld zone having structural characteristics distinct from adjacent non-welded areas of the first and second conductive members.

51. The RFID device of claim 50, wherein the first conductive member comprises an RFID strap and the second conductive member comprises an antenna.

52. The RFID device of claim 51, wherein the RFID strap comprising: a central portion for mounting an RFID chip; and two extended contacting portions extending outward from the central portion to form galvanic connection with the antenna.

53. The RFID device of claim 50, wherein the localized weld zone is located on at two extended contacting portions of the strap and contact pads of the dipole antenna.

54. The RFID device of claim 50, further comprising a substrate supporting at least one of the first or second conductive members.

55. The RFID device of claim 50, further comprising an adhesive between non-welded portions of the first conductive member and the second conductive member.

56. The RFID device of claim 50, wherein the localized weld zone exhibits a microstructure characteristic of localized heating and cooling.

Images