Recyclable radio frequency identification transponder components and methods for producing the same

Abstract

Improved RFID devices and methods of production are disclosed that utilize more efficient RFID designs, thereby reducing production material waste and increasing recycling opportunities without compromising RFID device performance. Some exemplary embodiments of the improved RFID devices may utilize thinner metal foils, "hollowed out" metal foils, "tapeless" designs, or inlay designs, all of which may reduce material usage. Other exemplary embodiments may utilize low-impact and / or biodegradable adhesives, thereby increasing aluminum recycling and reducing environmental risks.

Description

[0001] Cross-references to related patent applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 768,080 filed on November 15, 2018, which is incorporated herein by reference and becomes a part of the present invention. Background Art

[0003] The present invention generally relates to a radio frequency identification (RFID) device and a method for producing the same. More specifically, the disclosed RFID device and method for producing the same utilize a more efficient RFID device design, thereby reducing production material waste and increasing recycling opportunities without compromising RFID device performance. Therefore, this specification specifically refers to the relevant information. However, it should be understood that aspects of the present invention are also equally applicable to other similar applications, devices and methods for producing the same.

[0004] Generally speaking, RFID refers to the use of electromagnetic energy to emulate a responding device (called an RFID "tag" or transponder) to identify itself and, in some cases, provide additional information and / or data stored in the tag. An RFID tag typically consists of a semiconductor device, commonly referred to as a "chip," on which memory and operating circuits are formed to an antenna. An RFID tag typically acts as a transponder, providing information stored in the chip's memory in response to a radio frequency interrogation signal received from a reader (also called an interrogator). For passive RFID devices, the energy from the interrogation signal also provides the necessary energy for the RFID tag device to operate.

[0005] RFID tags can be incorporated into or affixed to merchandise that a user wants to later identify and / or track. In some cases, the RFID tag can be affixed to the exterior of the merchandise using a clip, adhesive, tape, or other means, and in other cases, the RFID tag can be inserted into the merchandise, such as contained within packaging, placed within a container of one or more merchandise, or sewn into clothing. In addition, RFID tags have a unique identification number, which is usually a simple serial number consisting of a few bytes, with a check digit attached. This identification number is usually incorporated into the RFID tag during production. The serial number / identification number cannot be changed by the user, and the manufacturer guarantees that each RFID tag serial number is used only once and is therefore unique. Such read-only RFID tags are usually permanently affixed to the merchandise that needs to be identified and / or tracked, and once attached, the serial number of the tag is associated with the master merchandise in a computer database.

[0006] These RFID devices typically include an antenna in combination with analog and / or digital electronics, such as communications electronics, data storage and control logic, and structures to support and protect the antenna and electronics and to mount or secure them to an item. RFID tags are RFID devices that can be attached to an item as part of a printed label with one side printed, or otherwise secured directly to the item. In contrast, RFID electronic tags are larger devices that are typically secured to an item using plastic fasteners, strings or other means.

[0007] Certain parameters are typically considered when designing all RFID devices. For example, the size and shape (i.e., form factor) of the RFID device is critical in most applications, as are other characteristics such as device flexibility. For a variety of reasons, such as security, aesthetics, and production efficiency, RFID manufacturers are very inclined to utilize smaller form factors. Therefore, since relatively thin profiles and flexibility are generally required, it is important to avoid the use of materials such as bulky electronic devices and RFID device structures that would unduly increase the thickness or stiffness of the RFID tag.

[0008] The most common components of an RFID device include a very small flexible chip and a flexible dipole antenna wound into a loop, whose actual length is about half the wavelength of the RFID device's operating frequency. The chip and antenna can be connected to structures called "carrier tape", "interposer" and "carrier" to facilitate device production. For the purpose of discussion, the carrier tape, interposer and carrier will be collectively referred to as "carrier tape" below.

[0009] These carrier tapes may be used as an electrical interface for routing between chip-related connectors and antenna-related connectors. The carrier tape may include conductive leads or pads that are electrically coupled to chip contact pads for coupling to the antenna. These conductive leads or pads may be used to provide a larger effective electrical contact area than would be possible if the chip were precisely aligned for direct placement without the use of a carrier tape or interposer. The larger effective electrical contact area may reduce the accuracy of chip placement required in production while still providing an effective electrical connection between the antenna and the chip. The use of such devices is useful in production because chip placement and mounting have historically been constrained in high-speed production, but may also result in more material consumption during the production process, increasing production costs, and is therefore not desirable.

[0010] In addition, RFID tags are widely and increasingly used in various industries where it is necessary to associate items with identification codes, and are applicable to almost any industry and any stage of small-scale and large-scale production. For example, RFID tags can be paired with produced parts, such as automotive parts, to track their progress on the assembly line. RFID tags can also be paired with finished products to track their progress during order fulfillment and / or shipment and subsequent use. In addition, RFID can also be used in various service and entertainment industries, such as smart channels in amusement parks, to better manage customers and track customer consumption. RFID tags can also be implanted in biological organisms, such as livestock and pets, for easy identification and / or tracking.

[0011] So, overall, the RFID market is very substantial. For example, it is estimated that as of 2017, the total RFID market is worth more than $11 billion, with approximately 18.2 billion RFID tags sold, of which nearly half (or 8.7 billion tags) are used for clothing alone. Furthermore, it is estimated that this only represents about 20% of the total clothing market, which means that there is huge room for growth in the clothing industry. Similarly, it is estimated that more than 800 million RFID tags have been embedded in transportation tickets, and more than 400 million tags have been embedded in animals, such as livestock and pets.

[0012] Furthermore, many of the above applications only require the use of the RFID tag for a relatively short period of time. After that period of time, the RFID tag need not be retained and can even be removed if desired. For example, if the RFID tag is used to track inventory and packages, the tag can be removed from the inventory at a certain stage of the process (e.g., when the manufactured product is assembled), and the tag can also be removed from the package when the package is transported to its intended destination. Similarly, for an RFID tag embedded in a transportation ticket, it is likely to be discarded when the recipient arrives at the intended destination.

[0013] Because RFID tags are produced and sold in very large quantities, even a negligible saving in production materials or costs per RFID tag can have a very significant financial impact on the manufacturer. For example, even if the reduction in total production mass is only noticeable at the million-tag level, there is still potential value to be realized because this can amount to a very large amount when billions of a particular RFID tag are produced. Similarly, a large amount of RFID materials can be recycled after the production process is completed under the right conditions. Therefore, due to the scale involved, even a negligible improvement in recycling convenience can be very beneficial if the percentage of recyclable material increases slightly.

[0014] Significant cost savings may also be realized from other components of the RFID production process. For example, the production process for RFID tags often involves adhesive processing. Therefore, the costs associated with applying, handling and / or recycling adhesives may be significantly reduced, which would be of great benefit. At the same time, the reduction in costs associated with mounting the chip to the antenna may also provide significant savings to manufacturers. In addition, while many RFID tags themselves are only useful for a short period of time, such as a period of time for shipping labels, it is also possible to recycle some used RFID tags or their materials.

[0015] Therefore, there is a long-standing need in the art for more efficient RFID designs and production methods that can reduce production waste. There is also a long-standing need in the art for RFID designs and production methods that can increase recycling opportunities. Finally, there is also a long-standing need for RFID designs and production methods that can achieve the above goals without compromising the performance of the RFID device. Summary of the invention

[0016] This article describes various improvements in RFID components and their production methods that can reduce production waste and increase recycling opportunities, all without compromising RFID device performance.

[0017] According to an exemplary embodiment, the improved RFID device may be constructed so that the total mass of material used in its construction is reduced (e.g., perhaps aluminum or a similar metal or alloy), or the mass of material consumed in the production of the RFID device is reduced. This may reduce the costs associated with the production of the RFID device, or reduce or offset the production costs through more efficient recycling.

[0018] In an exemplary embodiment, the RFID manufacturing process can be improved by removing metal foil in areas where it is not needed during the manufacturing process or in the final RFID device. For example, according to some exemplary embodiments, based on the current image of the RFID device, it can be determined that there are some areas where the removal of conductors has little effect on the overall device performance. For example, in order to reduce the amount of material consumed in the manufacturing process and increase the amount of material that can be recycled as part of the production (in the factory) or can be recycled immediately after production, the RFID antenna should have fewer such areas, or less material in such areas. In an exemplary embodiment, the above reduction can be achieved by "hollowing out" the RFID antenna, removing the conductive area in the center of the RFID antenna, but the premise is that the removal of such conductive material has little effect on the overall device performance. In another exemplary embodiment, when some or all of the conductive areas are printed in the form of a solution such as silver ink, the conductive area can be reduced by reducing the amount of solution used.

[0019] By better adjusting the printed RFID antenna according to the relevant materials, the material consumed in the production process can also be reduced. More specifically, according to an exemplary embodiment, it may be necessary to form an RFID antenna on a metal foil that does not require the use of a matrix carrier tape between the RFID antennas. For example, in an exemplary embodiment, a strip antenna (or an antenna similar to a strip antenna) can be used. This similar antenna (hereinafter referred to as a "carrier-free" antenna) may be similar to a strip antenna with a T cut out and a pitch angle of zero. The use of such an antenna design ensures that the vast majority of the metal foil (for example, close to 100%) is converted into an RFID antenna and the remaining metal foil is cleanly recycled, but all premise is that there is no matrix carrier tape. Ordinary technicians in this field also understand that the carrier tape used to fix the RFID chip to the antenna can also be recycled, and if possible, the RFID chip or silicone can also be recycled.

[0020] According to another exemplary embodiment of the present invention, in order to reduce the amount of material used to produce each RFID device while maintaining an acceptable level of RFID device performance, an antenna type that is most suitable for the intended RFID device can be carefully selected. In addition, it is also understood that different shapes and different types can be used to prepare and produce RFID antennas. In some exemplary embodiments, these shapes may vary due to production operations or intended applications, or based on any other criteria that meet user needs and / or preferences. For example, according to an exemplary embodiment, an RFID antenna can be prepared in an appropriate shape so that it can be more effectively embedded with other RFID antennas printed on the same sheet, increase the aluminum area that can be used to form the RFID antenna, and reduce the waste of aluminum area. Although square antennas are generally the most common in the art, it can be noted that another shape such as a triangle, a hexagon, or other geometric or non-geometric shapes can also be more effectively embedded, so the other shapes can be used instead of square antennas to save aluminum area and reduce waste.

[0021] In another exemplary embodiment, it may be necessary to prepare antennas of multiple different shapes and / or multiple different sizes on the sheet to fully maximize the space, and the antenna sheet may be tiled with multiple different geometric shapes or multiple different sizes of geometric shapes (or both) to maximize space efficiency. In some exemplary embodiments, these antenna shapes may be regular polygons, irregular polygons, or any other geometric or non-geometric shapes that meet user preferences, all of which may be formed on the same sheet to increase efficiency and reduce waste. In some exemplary embodiments, it is understood that when mixed RFID antennas are used, such as RFID antennas of different shapes or sizes, the RFID antennas may also be of different types. For example, in some exemplary embodiments, the RFID antennas may use different processes, such as direct and carrier tape connections. In the present invention, "direct connection" refers to direct connection between RFID antennas, and "carrier tape connection" refers to connection using the carrier tape described in other parts of this document.

[0022] According to another exemplary embodiment of the present invention, the thickness of the metal foil used in the production of the RFID antenna may vary. For example, the thickness of the RFID antenna currently made of 15 micron metal foil can be reduced so that a thinner metal foil, such as a 3 micron metal foil (if allowed) can be used. In some exemplary embodiments, due to the skin depth effect, it may be allowed to use a thinner metal foil. For example, the RFID signal received by the antenna can be distributed by the antenna so that the induced current density is the largest near the surface of the RFID antenna and decreases with the increase of the conductor depth, and the depth is based on the conductor material. Therefore, even a metal foil with a greatly reduced size can conduct a large amount of current and receive RFID signals. Other metal foils of different sizes can also be used, such as a size with a thickness less than 3 microns, and the reference thickness of 3 microns should not be considered as a limitation.

[0023] However, it should be understood that the use of very thin metal foils may present other production challenges, particularly in the area of ​​mechanical handling. For example, it is impractical to attempt to transport or dispense metal foils having a thickness less than that currently used in the art, and it is even more impractical to attempt to use such metal foils to manufacture very small parts because of the high likelihood of damaging the parts due to improper mechanical handling. Therefore, when using thinner metal foils, a mechanism for handling such metal foils and metal foil parts of such size must be introduced. According to an exemplary embodiment, in order to thicken the metal foil parts for ease of handling, the thinner metal foils may be provided with a paper base. For example, the metal foil may be prepared and provided in the form of a foil roll with a paper backing parallel to the metal foil so that the parts can be removed from the metal foil along the paper backing, and the paper backing can be removed after the parts are used.

[0024] Alternative paper backings and alternative mechanical handling methods for thin RFID device foils are also contemplated. In some exemplary embodiments, alternative paper backings and alternative mechanical handling methods for thin RFID device foils can be used to significantly reduce the amount of aluminum consumed in the production of RFID devices. For example, according to exemplary embodiments, where a production process using 15 micron aluminum foil is changed to using 3 micron aluminum foil, the amount of aluminum used in the production of RFID antennas can be reduced by 80%, or more than 80% if thicker aluminum is used to produce certain parts, such as carrier parts, for ease of handling.

[0025] According to another exemplary embodiment of the present invention, the improved RFID device can be produced at a lower production cost due to reduced costs (except for costs related to the amount of aluminum used). For example, the lower production cost can be achieved due to the interaction of the adhesive with the aluminum on which the improved RFID device is located. More specifically, an appropriate adhesive can be selected to increase the recyclability of the improved RFID device, thereby making it easier to recycle the aluminum used in its production. According to such exemplary embodiments, in addition to existing UV-curable materials used in the art, a simple adhesive can be used to adhere some or all of the RFID antennas, which adhesive is more favorable than UV-curable adhesives in terms of impact on the waste stream. More specifically, a simple adhesive that has little impact on the waste stream and is easily removed can be used, thereby making it easier to recycle the aluminum.

[0026] Furthermore, in some exemplary embodiments, a patterned adhesive may not be used in the construction of the RFID antenna. For example, for the "tapeless" antenna described above, a coating may be used instead of a patterned adhesive. More specifically, a polyvinyl alcohol (PVA) adhesive may be used as a coating, and the coating may be allowed to eventually biodegrade. Alternatively, other adhesives (such as starch adhesives) may be used, which may allow the coating to eventually biodegrade, or allow for easier removal of the coating using special solvents.

[0027] Alternatively, in another exemplary embodiment, it may be desirable to pattern the RFID antenna using a variant form of adhesive (other than a UV curing adhesive). For example, one may consider coating the RFID antenna with a special type of adhesive, such as a starch adhesive, so that the starch adhesive is in a tacky state. In a next step, the negative image of the RFID antenna may be printed in oil, the uncarrier antenna (as described above) may be patterned, and then normal cutting and stripping procedures known in the art may be performed. In certain exemplary embodiments, it may also be desirable for some or all of these components to be biodegradable. For example, vegetable oils may be used during the patterning process to ensure biodegradability.

[0028] In another exemplary embodiment of the improved RFID device, the chip used in the RFID device may be different from existing chips in order to reduce the impact of the chip on the waste stream. For example, in order to reduce the impact of the chip, a chip with a smaller actual size can be used. Alternatively, if the chip procurement cost can be reduced, it may be necessary to use a chip with a larger actual size. For example, it is easier to save costs for a group of RFID chips installed in an RFID device, and if the cost can be saved and it does not affect the overall profile of the RFID device, a larger chip, such as a programmable intelligent computer (PIC) or another similar chip, can be used. In contrast, it may not be so easy to save costs for a group of RFID tags because the space may be more limited and it may be necessary to use a low-profile chip, such as a small 200 micron x 400 micron silicon wafer.

[0029] Additionally, RFID devices are currently commonly used as part of tags affixed to recyclable materials, such as cardboard boxes, plastic bottles, fabrics, etc. Unfortunately, the RFID chip is the most expensive part of the structure, and although small, it uses energy and has difficult to recycle materials in its structure. Therefore, for cost and environmental purposes, it would be advantageous to be able to recover and reuse the RFID device when the product to which it has been affixed is recycled and / or otherwise discarded.

[0030] In the latest waste streams involving RFID tags or devices, product packaging is collected after being treated and processed in a recycling station to produce a reusable product such as paper pulp or plastic pellets. The RFID chip can be included in the output material, thus becoming a contaminant, reducing the value of the recycled material, or the material can be disposed of with the RFID chip.

[0031] To address this issue, at the recycling stage, consideration can be given to recovering RFID chips and returning them to RFID tag manufacturers or providers for reuse, thereby preventing RFID chips from being included in recycled materials or otherwise discarded. More specifically, recyclers can sell recycled RFID devices / chips to tag manufacturers, thereby improving the cost-effectiveness of overall material recovery and increasing recycling rates.

[0032] The recyclable near-field tape consists of a conductor loop that acts as an inductor and resonates with the chip capacitor at the desired frequency. When packaged, the device is encapsulated between two layers of film (PET) using an adhesive to prevent moisture ingress. In use, the near-field device is placed near the antenna and coupled to it, forming a far-field RFID device. Since the recycling process usually includes mechanical movements such as stirring and slurrying, it is best for the carrier tape to be as small as possible, such as using a minimum diameter. Therefore, the line width associated with the conductor loop should also be as small as possible to reduce the overall size of the device.

[0033] The modified carrier tape includes a multi-turn inductor. For example, the multi-turn coil requires the RFID chip to be connected to the inner and outer ends of the conductor, which can be achieved by winding a coil under the chip or using a secondary bridging conductor, formed as part of the double-sided etching process, or printed as an addition of conductive material. The conductor forming the coil can be a metal, such as aluminum foil, or printed conductive ink. An alternative method of making a carrier tape with a reduced diameter includes using a material with relatively high magnetic permeability in the central area, thereby increasing the inductance of the coil and making it smaller in diameter.

[0034] The present invention also contemplates a filtration system designed to isolate the presence of RFID devices in a waste stream and separate the volume to form a secondary waste stream wherein the density of RFID devices per unit volume is higher. More specifically, the system uses an RFID reader coupled to a known waste flow area (e.g., a pipe or conveyor) and a method for selectively diverting some of the waste stream. Depending on the nature of the waste stream, different types of RFID antennas and RFID couplers may be used. For example, when using liquid waste carriers such as water, a near field reader antenna is most suitable. In contrast, a far field RFID antenna may be more suitable for shredded waste on a conveyor.

[0035] In another alternative embodiment, the RFID loop and chip are encapsulated between two layers of foam material, so that its relative density is less than that of water and will float to the top of the water tank during the recovery process. More specifically, the foam may be compressed because the carrier tape is attached near the RFID antenna and is held in a compressed state by the RFID tag structure, minimizing the visual "bounce" of the uncompressed carrier tape. The carrier tape will then return to its uncompressed state when the RFID tag is recovered.

[0036] In another embodiment of the present invention, a portion of the magnetic field carrying area is occupied by a magnetic material such as mild steel. The use of magnetic material allows it to be separated using a magnetic field during the recycling process, thereby pulling the RFID device out of the remaining recycled material. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Advantages of the embodiments of the present invention will be apparent from the following detailed description of exemplary embodiments in conjunction with the accompanying drawings, in which like reference numerals represent like elements, wherein:

[0038] Figure 1 The present invention is an exemplary embodiment of a radio frequency identification transponder manufactured using a carrier tape provided by the prior art.

[0039] Figure 2 An exemplary alternative embodiment of an RFID transponder made using a carrier tape provided by the prior art.

[0040] Figure 3is an exemplary embodiment of a hexagonal coil that may be used in an exemplary embodiment of an RFID antenna.

[0041] Figure 4 An exemplary embodiment of a metal foil prepared for use with an exemplary damascene.

[0042] Figure 5 The present invention is an exemplary embodiment of a component assembly separated by a matrix carrier provided by the prior art.

[0043] Figure 6 An exemplary embodiment of a tapeless antenna assembly is shown.

[0044] Figure 7 This is an exemplary embodiment of an unloaded antenna.

[0045] Figure 8 The present invention is a flow chart for illustrating an improved method for producing a radio frequency identification device. DETAILED DESCRIPTION

[0046] In the following description of specific embodiments of the present invention and the related drawings, various aspects of the present invention are disclosed. Alternative embodiments may be designed without departing from the spirit or scope of the present invention. In addition, in order not to obscure the relevant details of the present invention, well-known elements of the exemplary embodiments of the present invention will not be described in detail or will be omitted. In addition, in order to facilitate understanding of the description, the terms used herein are discussed below.

[0047] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." The embodiments described herein are exemplary embodiments only and are not limiting. It should be understood that the embodiments described are not necessarily to be considered preferred or advantageous over other embodiments. Furthermore, the terms "embodiments of the invention," "embodiments," or "invention" do not require that all embodiments of the invention include the discussed feature, advantage, or mode of operation.

[0048] In addition, many embodiments are described in terms of an order of operations performed by elements of a computing device. It should be recognized that the various operations described herein may be performed by a dedicated circuit (e.g., an application specific integrated circuit (ASIC)), program instructions executed by one or more processors, or a combination of both. In addition, the order of operations described herein may be considered to be fully contained in any form of computer-readable storage medium having stored therein a corresponding set of computer instructions that, when executed, cause the associated processor to perform the functions described herein. Thus, various aspects of the present invention may be embodied in a variety of different forms, all of which are considered to be within the scope of the subject matter. In addition, for the various embodiments described herein, the corresponding form of any such embodiment may be described herein as "configuration logic" for performing the operations described.

[0049] Referring now to the accompanying drawings, various exemplary embodiments of improved RFID devices and methods of production and possible recycling thereof are disclosed. As background technology, Figure 1 to Figure 2 FIG. 1 is an exemplary embodiment of a prior art RFID transponder 100 made using a tape carrier 104. The RFID transponder 100 preferably includes a pair of spaced apart connectors 102, each of which is provided with a respective lead 106. According to an exemplary embodiment, the tape carrier 104 can provide an electrical interface for routing between the connectors 102, such as chip-related connectors and antenna-related connectors, thereby facilitating the production of the transponder 100. More specifically, the tape carrier 104 can be positioned over the leads 106 and can also extend between the leads, so that the transponder 100 can be easily manufactured even if the tape carrier 104 is misaligned (e.g., Figure 2 As shown), bridging can still be achieved between the respective leads 106.

[0050] Figure 3 is an exemplary embodiment of a hexagonal coil 300 that may be used in an exemplary embodiment of an RFID antenna. According to an exemplary embodiment, the characteristics of the coil structure 300 may be determined by its outer diameter (e.g., the distance from one side to the other), its inner diameter (e.g., the diameter of the inner hole around which the conductive material of the hexagonal coil 300 is wound), the width of the coil 300, and the spacing between consecutive loops of the coil 300. According to an exemplary embodiment, the coil 300 may be arranged or constructed to minimize the material used in the coil 300, which may reduce the material costs associated with the production of the RFID device and / or reduce the production costs through more efficient recycling.

[0051] More specifically, as described above, the RFID manufacturing process can be improved by removing metal foil in areas where it is not needed during the manufacturing process or in the final RFID product. For example, based on the current image of the RFID device, it can be determined that there are some areas where the removal of the conductor has little effect on the overall RFID device performance. Therefore, in order to reduce the amount of material consumed in the manufacturing process and increase the amount of material that can be recycled as part of the production (in the factory) or can be recycled immediately after production, the RFID antenna should have fewer such areas, or less material in such areas. In an exemplary embodiment, the above results can be achieved by "hollowing out" the RFID antenna, removing the conductive area in the center of the RFID antenna, but the premise is that the removal of such material has little effect on the overall device performance. In another exemplary embodiment, when some or all of the conductive areas are printed in the form of a solution such as silver ink, the conductive area can be reduced by reducing the amount of solution used.

[0052] According to another exemplary embodiment of the present invention, in order to reduce the amount of material used to produce each RFID device while maintaining an acceptable level of RFID device performance, an antenna type that is most suitable for the intended RFID device can be carefully selected. More specifically, RFID antennas can be prepared and produced in different shapes, which may vary depending on the production run or intended application, or based on any other criteria that meet user needs and / or preferences. For example, an RFID antenna can be prepared in an appropriate shape to more effectively fit with other RFID antennas printed on the same sheet, increase the aluminum area that can be used to form an RFID tag, and reduce the waste of aluminum area, as described more fully below. Although square antennas are generally the most common in the art, other shapes such as triangles, hexagons, or other geometric or non-geometric shapes can also fit more effectively, so the other shapes can be used instead of square antennas to save aluminum area and reduce waste.

[0053] Figure 4 In one exemplary embodiment of a metal foil prepared for use with exemplary tessellation 302, such tessellation may be generally described as an arrangement of shapes that fit closely together, particularly an arrangement of polygons in a repeating pattern without gaps or overlaps. More specifically, metal foil may be prepared for use with tessellation 302, such tessellation utilizing any shape or combination of shapes, such as triangles 304, squares 306, and regular hexagons 308, one of which features a hexagonal coil 300. In one embodiment, coil 300 may be comprised of some or all of the shapes in tessellation 302, as desired. For example, within each square 306, a square coil for a typical RFID antenna may be formed (square coils may be most commonly used), within each triangle 304, a triangular coil may be formed, and within each hexagon 308, a hexagonal coil may be formed, such as hexagonal coil 300. Other shapes or combinations of shapes may also be used, for example, coil 300 may be formed in a different shape than the shape in which it is located. For example, multiple square coils may be formed within a rectangle, as desired.

[0054] In another embodiment of the present invention, it may be necessary to prepare antennas of multiple different shapes and / or multiple different sizes on the sheet to fully maximize the space, and the antenna sheet may be tiled with multiple different geometric shapes or multiple different sizes of geometric shapes (or both) to maximize space efficiency. In some exemplary embodiments, these antenna shapes may be regular polygons, irregular polygons, or any other geometric or non-geometric shapes that meet user preferences, all of which may be formed on the same sheet to increase efficiency and reduce waste. In some exemplary embodiments, it will be understood that when hybrid RFID antennas are used, such as RFID antennas of different shapes or sizes, the RFID antennas may also be of different types. For example, in some exemplary embodiments, the RFID antennas may use different processes, such as direct and strip carrier tape connection, a more comprehensive description of which is provided below.

[0055] In another exemplary embodiment of the present invention, the thickness of the metal foil used in the production of the RFID antenna may be varied. For example, as described above, the thickness of the RFID antenna currently made of 15 micron metal foil may be reduced so that a thinner metal foil, such as a 3 micron metal foil, may be used. The use of a thinner metal foil may be permitted due to the skin depth effect. For example, the RFID signal received by the antenna may be distributed by the RFID antenna so that the induced current density is greatest near the surface of the RFID antenna and decreases with increasing depth of the conductor, which is based on the conductor material. Therefore, even a metal foil of greatly reduced size is able to conduct a large amount of current and receive a signal.

[0056] However, those skilled in the art will appreciate that the use of very thin metal foils may present other production challenges, particularly in the area of ​​mechanical handling. For example, it is impractical to attempt to transport or dispense metal foils having a thickness less than that currently used in the art, and even more impractical to attempt to use such metal foils to manufacture very small parts, as the likelihood of damaging the parts due to improper mechanical handling is high. Therefore, when using thinner metal foils, it is generally necessary to introduce an effective mechanism for handling such metal foils without damaging the metal foils. According to an exemplary embodiment, in order to thicken the metal foil parts for easier handling, the thinner metal foils may be provided with a paper base. For example, the metal foil may be prepared and provided in the form of a foil roll with a paper backing parallel to the metal foil so that the parts can be removed from the metal foil along the paper backing, and after the parts are used, the paper backing can be removed. Alternative paper backings and alternative mechanical handling methods for thin metal foils for RFID devices are also contemplated. For example, alternative paper backings and alternative mechanical handling methods for thin metal foils for RFID devices may be used to significantly reduce the amount of aluminum consumed in the production of RFID devices.

[0057] In another exemplary embodiment of the present invention, the improved RFID device may be produced at a lower production cost due to reduced costs (other than costs associated with the amount of aluminum used). For example, the lower production cost may be achieved due to the interaction of a particular adhesive with the aluminum in which the improved RFID device is located. More specifically, a suitable adhesive may be selected to increase the recyclability of the improved RFID device, thereby making it easier to recycle the aluminum used in its production. In addition to the UV curable adhesives currently used in the art, other suitable adhesives may be used to adhere some or all of the RFID antennas together and to the device, which adhesives may have a minimal impact on the waste stream and be easily removed from the device, thereby making it easier to recycle the aluminum.

[0058] Figure 5 An exemplary embodiment of a prior art assembly of parts 500 separated by a matrix strip carrier tape 502 is shown. In this exemplary embodiment, the parts 500 may be formed in spaces 504 between the matrix strip carrier tapes 502, which may be used to separate each part 500. In addition, each space 504 between the matrix strip carrier tapes 502 may further include an alignment mark 506. Waste may also be reduced by better aligning the printed RFID antenna with the associated material. More specifically, according to an exemplary embodiment, it may be desirable to form an RFID antenna on a metal foil that does not require the use of a matrix strip carrier tape 502 between the antennas. For example, in an exemplary embodiment, a strip antenna (or an antenna similar to a strip antenna) may be used. Such a similar antenna (hereinafter referred to as a "stripless carrier tape" antenna) may be similar to a strip antenna with a T-shape cut out and a pitch angle of zero. Using such an antenna design ensures that the vast majority of the metal foil (e.g., close to 100%) is converted into an RFID antenna and the remaining metal foil is cleanly recycled, but all on the premise that there is no matrix strip carrier tape 502. It is also understood by those skilled in the art that the carrier tape used to secure the RFID chip to the antenna may also be recycled, and if possible, the RFID chip or the silicone may also be recycled.

[0059] Figure 6An exemplary embodiment of an assembly 600 without stripe carrier tape antennas 604 is shown, wherein the antennas 604 may be closely adjacent to each other, such that the majority of the metal foil is converted into antennas 604, except for the T-shape 606 cut out of each antenna. More specifically, an antenna 604 may be formed such that one antenna 604 shares a border 602 with an adjacent antenna 604, thereby eliminating the need for a matrix stripe carrier tape 502. In other exemplary embodiments, a matrix stripe carrier tape 502 may be placed on one or more sides of the antennas 604, if desired. For example, a matrix stripe carrier tape 502 may be placed along the length 608 of each row of antennas 604, such that the T-shape 606 of each row of antennas 604 is connected to the matrix stripe carrier tape 502. After the T-shape material 606 is separated from the remaining metal foil, it is easier to separate the antennas 604 from the T-shape material 606 because the use of the matrix stripe carrier tape 502 ensures that the T-shape material 606 can be removed in one piece. Other configurations of antenna assembly 600 are also contemplated, for example, the T-shape 606 of one antenna 604 in antenna assembly 600 may be a mirror image of the T-shape 606 of another antenna 604 in antenna assembly 600, which together form a larger I-shape that is easier to store after removal.

[0060] In some exemplary embodiments, T-shape 606 may be of any size or shape that meets the needs and / or preferences of a user. For example, according to one exemplary embodiment, T-shape 606 may be arbitrarily thin and may involve the removal of very little material. In another exemplary embodiment, T-shape 606 may be arbitrarily large and may involve the removal of more material. In some exemplary embodiments, the remaining material may be provided at a set thickness along the entire length. In other exemplary embodiments, the remaining material may be provided at a variable thickness along the length. Other variations of T-shape 606 are also contemplated, and T-shape 606 does not necessarily have to resemble a "T". For example, other shapes, including but not limited to Y-shape, may also be used to meet user needs and / or preferences.

[0061] Figure 7 704 is an alternative exemplary embodiment of a stripless carrier antenna 704. The stripless carrier antenna 704 is generally strip-shaped or rectangular, and may have a T-shape 706, which may be removed from the antenna 704 during production. The antenna 704 preferably includes a uniform thickness 712, a height 708, and a width 710, which may determine the characteristics of the antenna 704. It is generally understood that the larger the area of ​​the antenna 704, the more energy it collects and the more RFID chip channels it has, and the wider the reading range of the RFID device.

[0062] It can also be understood that for a strip antenna, such as antenna 704, the antenna inductance can be defined as:

[0063]

[0064] Where all units are centimeters, a is the wire radius (unit: centimeters, so the total thickness of the antenna is 2a), l c equal A is equal to the coil area l a × b Other equations may also be used to define the characteristics of antennas that are shaped other than strip antenna 704 or have other variations.

[0065] Figure 8 800 is a flow chart for illustrating an improved RFID device production method. In step 802, the manufacturer may prepare a thin metal foil with a paper backing, or otherwise introduce the thin metal foil into the production process. In step 804, the manufacturer may prepare an antenna arrangement, such as a stripless carrier antenna arrangement or another effective antenna inlay, which will eventually be cut from the thin metal foil. As described above, in certain exemplary embodiments, it may also be desirable for some or all of the RFID devices to be biodegradable. For example, vegetable oils may be used during the patterning process to ensure biodegradability. Therefore, in step 806, the antenna inlay may be coated with a biodegradable adhesive.

[0066] In the next step 808, the mosaic may be patterned prior to cutting, which may involve printing a negative image in oil above the adhesive layer. However, as described below, the mosaic does not necessarily need to be patterned prior to cutting. In step 810, the mosaicked metal foil may be subjected to normal cutting and peeling procedures, and then the remaining RFID production process may be carried out as currently understood in the art.

[0067] Alternatively, in another exemplary embodiment, it may be desirable to pattern the RFID antenna using a variant form of adhesive (other than a UV-curable adhesive or a biodegradable adhesive). For example, one may consider coating the RFID antenna with a special type of adhesive, such as a starch adhesive, so that the starch adhesive is in an adhesive state. Alternatively, in some exemplary embodiments, a patterned adhesive may not be used when constructing the RFID antenna. For example, for the "stripless carrier" antenna described above, a coating may be used instead of a patterned adhesive. More specifically, a polyvinyl alcohol (PVA) adhesive coating may be used and the coating may be allowed to eventually biodegrade.

[0068] As background to recycling opportunities relevant to the present invention, RFID devices are often affixed to recyclable materials such as cardboard boxes, plastic bottles, fabrics, etc. Unfortunately, the chip portion of the RFID device is the most expensive part of the RFID device structure and is also often the most difficult part to effectively recycle or remove from the underlying carrier material to make the carrier material recyclable. Therefore, it would be advantageous to be able to recover and reuse the RFID device when recycling and / or otherwise discarding the product to which it has been affixed.

[0069] In the latest waste streams involving RFID devices, product packaging is collected after treatment and processing at a recycling station to produce a reusable product, such as paper pulp or plastic pellets. Unfortunately, the RFID chip can be included in the output material, thereby becoming a contaminant, reducing the value of the recycled material, or the material is processed along with the RFID chip due to the expense and time required to separate the two. Therefore, there is a long-standing need in the art for the ability to recover RFID devices and / or chips at the recycling stage and return them to the RFID manufacturer or provider for reuse. More specifically, the recycling station can sell the recovered RFID devices / chips to the tag manufacturer, thereby improving the cost-effectiveness of overall material recovery and increasing recycling rates.

[0070] In one possible embodiment of the invention, the recyclable near-field tape includes a conductor loop that acts as an inductor and resonates with the chip capacitor at the desired frequency. When packaged, the device is encapsulated between two layers of film (PET) using an adhesive to prevent moisture from entering. In use, the near-field device is placed near the antenna and coupled to the antenna, thereby forming a far-field RFID device. Since the recycling process usually includes mechanical movements such as stirring and slurrying, the tape carrier and line width associated with the loop should be as small as possible to reduce the overall size of the device.

[0071] Modified strip carriers may further include multi-turn inductors. For example, a multi-turn coil requires the RFID chip to be connected to the inner and outer ends of the conductor, which can be achieved by winding a coil under the chip or using a secondary bridging conductor, formed as part of the double-sided etching process, or printed as an addition of conductive material. The conductor forming the coil may include a metal, such as aluminum foil, or printed conductive ink. An alternative method of making a strip carrier with a reduced diameter includes using a material with relatively high magnetic permeability in the center area, thereby increasing the inductance of the coil and making it smaller in diameter.

[0072] The present invention also contemplates a filtration system designed to isolate the presence of RFID devices in a waste stream and separate the volume to form a secondary waste stream wherein the density of RFID devices per unit volume is higher. More specifically, the filtration system may include an RFID reader coupled to a known area of ​​the waste stream (e.g., a pipe) and a method for selectively diverting selected portions of the waste stream. Depending on the nature of the waste stream, different types of RFID antennas and RFID device couplers may be used. For example, when using a liquid fluid carrier such as water, a near field reader antenna is most suitable. In contrast, a far field RFID antenna may be more suitable for shredded material on a conveyor.

[0073] In another alternative embodiment, the RFID loop and chip are encapsulated between two layers of foam material, so that its relative density is less than that of water and will float to the top of the water tank during the recovery process. More specifically, the foam may be compressed because the strap carrier is attached near the RFID antenna and is held in a compressed state by the RFID tag structure, minimizing the visual "bounce" of the uncompressed strap carrier. The strap carrier will then return to its uncompressed state when the RFID tag is recovered.

[0074] In another embodiment of the present invention, a portion of the magnetic strip carrier area is occupied by a magnetic material such as mild steel. The use of magnetic material allows it to be separated using a magnetic field during the recycling process, thereby pulling the RFID device out of the remaining recycled material.

[0075] The above description and accompanying drawings illustrate the principles, preferred embodiments and operating modes of the present invention. However, the present invention should not be limited to the specific embodiments described above. Other variations of the above embodiments will be apparent to those skilled in the art (for example, features associated with certain configurations of the present invention may also be associated with any other configuration of the present invention, as desired).

[0076] Therefore, the above embodiments should be regarded as illustrative embodiments rather than limiting embodiments. It should be appreciated that modifications may be made to these embodiments by those skilled in the art without departing from the scope of the present invention as defined by the following claims.

Claims

1. A method for producing a radio frequency identification device, characterized in that: The following steps are involved: providing metal foil; inlaying a plurality of RFID antenna patterns on the metal foil; and Cutting of metal foil; Wherein, the RFID device production method further comprises a step of coating the plurality of RFID antenna patterns with a biodegradable adhesive before cutting the metal foil, and a step of mosaic-patterning the plurality of RFID antenna patterns; Mosaic patterning of the plurality of RFID antenna patterns includes printing a negative image of one or more of the plurality of RFID antenna patterns in vegetable oil on the adhesive layer.

2. The method for producing a radio frequency identification device according to claim 1, characterized in that: Before inlaying the plurality of RFID antenna patterns on the metal foil, the method further includes a step of changing the shape of one or more of the plurality of RFID antenna patterns to optimize the inlaying of the plurality of RFID antenna patterns.

3. The method for producing a radio frequency identification device according to claim 2, characterized in that: Change the shape to a triangle, square, rectangle, or hexagon.

4. The method for producing a radio frequency identification device according to claim 1, characterized in that: The adhesive is a non-UV curing adhesive.

5. The method for producing a radio frequency identification device according to claim 4, characterized in that: The non-UV curing adhesive is polyvinyl alcohol adhesive or starch adhesive.

6. The method for producing a radio frequency identification device according to claim 1, characterized in that: Further comprising a metal foil thickness reducing step.

7. The method for producing a radio frequency identification device according to claim 1, characterized in that: Further included is the step of varying the thickness of the metal foil over the entire length of the metal foil.

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