RFID tag having wire antenna for tire

Abstract

The present invention relates to an RFID tag having a wire antenna having improved transmission / reception characteristics and, more particularly, to an RFID tag in which an RFID chip is mounted and connected to a substrate to which an antenna formed of a conductive high-strength metal wire and a meandering loop pattern are applied, and an antenna connection part is epoxy-molded. The substrate of the RFID tag of the present invention for solving the technical problem may be characterized in that an antenna pattern having a loop structure connecting two terminals of the RFID chip is formed thereon.

Description

RFID tag equipped with a wire antenna for tires

[0001] The present invention relates to an RFID tag equipped with a wire antenna having improved transmission / reception characteristics, and more specifically, to an RFID tag in which an antenna formed of a conductive high-strength metal wire is connected to a substrate having a meander-shaped loop pattern applied thereto, and the antenna connection portion is epoxy-molded.

[0002] RFID (Radio Frequency Identification) technology is a technology that uses radio frequencies to read data stored on tags, cards, labels, etc., which contain embedded microchips, without physical contact. Although existing barcode and magnetic card systems are widely used in our daily lives, this system was developed in response to changes in production methods, shifts in consumer awareness, advancements in culture and technology, and the demand to overcome the shortcomings of barcodes and magnetic cards.

[0003] RFID tags are characterized by the absence of mechanical contact, allowing for the remote transmission and reception of information using a reader, resulting in no friction or damage and minimal contamination or environmental impact.

[0004] Depending on the frequency used, this can be used differently for various purposes, such as low-frequency communication in the 100–500 kHz range, NFC communication in the 13.56 MHz range, and ultra-high frequency (UHF) communication in the 860–960 MHz range.

[0005] RFID tags store information about a product for product identification and can be attached to the product's exterior or packaging box to be used for product management.

[0006] Dual ultra-high frequency (UHF) RFID tags have the longest reading range and are generally used in applications requiring longer reading ranges, such as supply chain management and asset tracking.

[0007] Technology development is needed to provide RFID tags that satisfy a long reading range, ensure durability, and minimize size so they can be embedded in various products.

[0008] Tires are an example of a product equipped with RFID tags of such specifications. Smaller tires are advantageous for embedding and require a long recognition distance, while simultaneously ensuring durability against harsh operating environments.

[0009] The technical problem that the present invention aims to solve is to provide an RFID tag that satisfies a long reading range, minimizes changes in transmission / reception characteristics caused by changes in dielectric constant due to the surrounding environment, secures durability by minimizing deformation caused by external impact, high temperature, high pressure, etc., and minimizes size so that it can be embedded and used in various products.

[0010] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0011] An RFID tag having a wire antenna of the present invention for solving the above technical problem may be characterized by comprising a substrate, an RFID chip mounted on the substrate, a wire antenna assembled on the substrate and connected to each of two terminals of the RFID chip, and a central molding portion surrounding the connection portion between the RFID chip and the wire antenna, and having an antenna pattern having a loop structure connecting the two terminals of the RFID chip formed on the substrate.

[0012] In some embodiments of the present invention, the wire antenna may have a conductive wire formed in a zigzag shape.

[0013] In some embodiments of the present invention, the conductive wire may be formed by plating it with brass one or more times.

[0014] In some embodiments of the present invention, the conductive wire may be formed of a high-strength metal.

[0015] In some embodiments of the present invention, one end of the wire antenna may be fixed to a first via hole formed at the leading end of the substrate, and the other end may be fixed to a second via hole formed adjacent to the RFID chip.

[0016] In some embodiments of the present invention, the second via hole may be connected to a terminal at one end of the RFID chip via a first antenna pattern and to a terminal at the other end of the RFID chip via a second antenna pattern.

[0017] In some embodiments of the present invention, the first antenna pattern may be formed on the component surface of the substrate, and the second antenna pattern may be formed on the copper foil surface of the substrate.

[0018] In some embodiments of the present invention, the antenna pattern of the substrate may be formed as a meander-shaped line.

[0019] In some embodiments of the present invention, the part may wrap the second via hole and the antenna pattern.

[0020] In some embodiments of the present invention, the central molding portion may be formed of an epoxy material.

[0021] In some embodiments of the present invention, the substrate may include a substrate hole formed by penetrating a portion thereof.

[0022] In some embodiments of the present invention, the resonant frequency of the wire antenna and the antenna pattern may be formed at a frequency in the ultra-high frequency (UHF) band.

[0023] The tire of the present invention for solving the above technical problem may include the RFID tag.

[0024] The RFID tag equipped with a wire antenna according to the present invention satisfies a long reading range and durability, while simultaneously minimizing its size so that it can be embedded in various products. Furthermore, it can be easily manufactured by installing a zigzag-shaped wire antenna on the upper surface of a substrate. By providing an RFID tag with improved RF characteristics, durability, and productivity, the distribution of RFID tags can be expanded.

[0025] In particular, compared to helical antennas for tires formed using conventional technology, this invention can resolve the issue of RF characteristic deviations caused by the pitch spacing of the helical antennas narrowing or widening due to rubber entering between the antennas during assembly for embedding in a tire, as well as the difficulty of the manufacturing process of pushing the helical antennas into a substrate. Furthermore, since the wire antenna of the present invention is assembled onto a substrate in a planar shape, productivity is significantly improved and RF characteristic deviations caused by assembly variations can be minimized.

[0026] FIG. 1 is a drawing showing an RFID tag according to one embodiment of the present invention.

[0027] FIG. 2 is a drawing showing a substrate of an RFID tag according to one embodiment of the present invention.

[0028] FIG. 3 is a diagram showing the directional pattern characteristics of an RFID tag according to one embodiment of the present invention.

[0029] FIG. 4 is a diagram showing the transmission and reception range per frequency of an RFID tag according to an embodiment of the present invention and the minimum transmission power of a reader that the tag can recognize.

[0030]

[0031] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0032] "And / or" includes each of the mentioned items and all combinations of one or more.

[0033] The terms used herein are for describing embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprising" and / or "comprising" does not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0034] Furthermore, throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly" or "electrically connected" with other members or elements in between.

[0035] Additionally, throughout the specification, the description that each layer (film), region, pattern, or structure is formed "on" or "under" the substrate, each layer (film), region, pad, or pattern includes both direct formation and formation through another layer. The criteria for "on" or "under" each layer are described based on the drawings.

[0036] Furthermore, expressions such as 'first, second,' etc., are used solely to distinguish multiple compositions and do not limit the order or other characteristics between the compositions.

[0037] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0038] FIG. 1 is a drawing showing an RFID tag according to an embodiment of the present invention, where (a) is a perspective view, (b) is a top view, and (c) is a side view, and FIG. 2 is a drawing showing a substrate of an RFID tag according to an embodiment of the present invention, where (a) is a top view and (b) is a bottom view.

[0039] Referring to FIG. 1 and FIG. 2, the RFID tag of the present invention may be characterized by comprising a substrate (10), an RFID chip (40) mounted on the substrate, a wire antenna (21) assembled on the substrate (10) and connected to each of two terminals of the RFID chip (40), and a central molding part (30) covering the connection part between the RFID chip (40) and the wire antenna (21), and having a loop structure antenna pattern formed on the substrate (10) that connects the two terminals of the RFID chip (40).

[0040] The above substrate (10) is a thin insulating plate on which the wire antenna (21) and the RFID chip (40) are fixed together, and a conductive pattern is formed on the insulating plate so that components can be fixed and connected by soldering. It may be a double-sided substrate in which the conductive pattern is formed on both the component surface and the copper foil surface, or a multilayer substrate in which two or more insulating plates are formed.

[0041] In particular, the substrate (10) according to the present invention is a highly reliable substrate with high temperature durability and can maintain stable characteristics even in harsh environments of low or high temperatures.

[0042] Additionally, the substrate (10) may include a substrate hole (13) formed by penetrating a portion of the substrate (10). According to one embodiment of the present invention, a case is shown in which the substrate hole (13) is formed in a long rectangular shape in a portion excluding the part supporting the mounted wire antenna (21). Even with the substrate hole (13) formed in this manner, the zigzag-shaped inflection portion of the wire antenna (21) can still be supported by the substrate (10).

[0043] The substrate hole (13) can add flexibility to the substrate (10) to make it resistant to deformation of the product to which the RFID tag is applied, and at the same time, provide a sense of unity with the product in which the RFID tag is embedded.

[0044] The RFID chip (40) is formed as an integrated circuit (IC) and can store RFID-related data and perform processing necessary for data transmission and reception with an RFID reader. The RFID chip (40) is connected to an antenna through a conductive connection. The RFID chip (40) is mounted in the form of die-chip bonding, die-chip wire bonding, or a package chip.

[0045] The wire antenna (21) can receive or transmit electromagnetic waves for wireless data transmission and reception. The wire antenna (21) is generally made by processing a conductive material, such as copper or aluminum, into a wire, and can be designed to resonate at a specific frequency, such as the pattern antenna described later.

[0046] In particular, the wire antenna (21) according to the present invention can be easily mounted on the upper surface of a substrate (10) after being formed by processing a high-strength metal wire and then plating it with brass at least once.

[0047] The wire antenna (21) is plated with brass so that it can be inserted into the hole of the substrate (10) to facilitate bonding during soldering and maintain bonding strength after bonding, and also has high conductivity to improve antenna sensitivity.

[0048] In addition, when embedded in a tire, it has excellent bonding properties with the tire. Typically, a substrate (10) made of a polymer resin does not have excellent adhesive strength because it is bonded at the interface with the rubber inside the tire. However, the RFID tag according to the present invention can increase the adhesive strength with the tire by minimizing the area of ​​the substrate (10) exposed inside the tire and expanding the contact area with the wire antenna (21) formed of a brass plated surface.

[0049] As previously announced, oxidizing the metal improves friction and enhances adhesion to the rubber material. Therefore, to improve the adhesion between the metal antenna and the internal rubber, the antenna can be oxidized; however, in this invention, brass plating is introduced as an alternative method that produces the same effect as oxidation.

[0050] Also, since the wire antenna (21) is formed of high-strength metal, it is resistant to external stress and has high resistance to vibration and rotation, and can minimize short circuits and shape changes caused by high heat.

[0051] One end of the wire antenna (21) according to the present invention may be fixed to a first via hole (11) formed at the leading end of the substrate, and the other end may be fixed to a second via hole (12) formed adjacent to the RFID chip (40).

[0052] The first via hole (11) is installed at both ends of the substrate, and the second via hole (12) is installed at the center of the substrate, so that the RFID tag according to the present invention may have a shape in which two wire antennas (21) are formed from the center of the substrate to both ends of the substrate.

[0053] The second via hole (12) can be connected to one end terminal (RF1) of the RFID chip (40) via a first antenna pattern (15) formed in a meander line shape, and can also be connected to the other end terminal (RF2) of the RFID chip (40) via a second antenna pattern (17) also formed in a meander line shape.

[0054] At this time, the first antenna pattern (15) may be formed on the component surface of the substrate (10), and the second antenna pattern (17) may be formed on the copper foil surface of the substrate (10).

[0055] In this way, an antenna pattern of a meander shape line with a loop structure connecting two terminals (RF1, RF2) of an RFID chip (40) can be formed by connecting the terminal (RF2) at one end to the other end by passing through the first antenna pattern (15), the second via hole (12), the second antenna pattern (17), and the other second via hole (12) and second antenna pattern (17) in sequence from the terminal (RF1).

[0056] The antenna pattern formed in this way can minimize changes in the antenna's resonance point caused by surrounding dielectric materials (rubber, plastic, etc.) and, by possessing good gain and directivity, offers significant improvements in range and RF characteristic stability compared to conventional RFID tags.

[0057] The substrate (10) and the wire antenna (21) can be strongly joined by soldering to two first via holes (11) and two second via holes (12).

[0058] However, the portion of the RFID chip (40) and the portion of the substrate (10) where the antenna pattern is formed are susceptible to external impact and may be contaminated or damaged by external foreign matter and other environmental factors. To prevent this, the connection portion can be protected by forming a central molding portion (30) that wraps the connection portion with a material such as epoxy or other resin.

[0059] At this time, since the central molding part (30) surrounds and protects the second via hole (12) where the wire antenna (21) is fixed to the substrate (10), the RFID tag according to the present invention can have strong durability against external shocks and environmental factors.

[0060] The lengths of the wire antenna (21) and pattern antennas (15, 17) can be formed to be 1 / 4 wavelength (λ) of the frequency of the ultra-high frequency (UHF) band.

[0061] λ / 4 = c / (4×f) = (3×10 8 ) / (4×918.5×10 6 ) = 0.08165 m (approx. 8.2 cm)

[0062] That is, the total length of the wire antenna (21) and pattern antennas (15, 17) according to the present invention can be formed to a length corresponding to 1 / 4 wavelength of a frequency of 900 MHz.

[0063] High-frequency (UHF) RFID tags operate at frequencies of 860 to 960 MHz and have the longest reading range among RFID technologies, so they are generally used in applications such as supply chain management and asset tracking that require a longer reading range.

[0064] The RFID tag according to the present invention is formed with a minimum size (40mm X 3.0mm X 1.2mm) optimized for the 900MHz frequency band and is designed for tires, but can be embedded in various objects such as the interiors of household electronic devices, industrial electronic devices, manual devices, household / industrial furniture, toys, automotive parts, tires, and buildings without affecting the external design. In particular, since it is designed to suit tires that require resistance to various climatic environments and high mechanical durability, it can be applied with excellent performance in the environments of other products as well.

[0065] FIG. 3 is a diagram showing the directional pattern characteristics of an RFID tag according to one embodiment of the present invention, where (a) shows the E plane and (b) shows the H plane.

[0066] Referring to FIG. 3(a), the radiation pattern of the resonant frequency E plane of the antenna of the present invention can be confirmed, and it can be seen that good radiation gain can be obtained in directions other than the length direction of the wire antenna (21).

[0067] Referring to Figure 3(b), the H-plane radiation pattern of the resonant frequency of the antenna of the present invention can be seen, indicating that it has good radiation gain in all directions.

[0068] As such, an RFID tag according to one embodiment of the present invention can have good radiation gain in all directions except the length direction of the wire antenna (21).

[0069] FIG. 4 is a diagram showing the transmission and reception range of an RFID tag by frequency and the minimum transmission power of a reader that the tag can recognize according to an embodiment of the present invention, where (a) is the recognition range by frequency and (b) is the reception power by frequency.

[0070] Referring to FIG. 4(a), the horizontal axis represents frequency in MHz units and the vertical axis represents recognition distance in m units, showing that data transmission and reception over the longest distance is possible at the resonant frequency of the RFID tag according to one embodiment of the present invention. The experimental results show 7 m at 900~920 MHz.

[0071] Referring to FIG. 4(b), the horizontal axis represents the frequency in MHz units, and the vertical axis represents the minimum transmission power of the reader that the tag can recognize in dBm units on a logarithmic scale, showing that the gain that can be recognized is greatest at the resonant frequency of the RFID tag according to one embodiment of the present invention. Experimental results indicate that a resonance point is formed at 900~920 MHz and that even the smallest power is recognized.

[0072] As such, an RFID tag according to one embodiment of the present invention can satisfy the required antenna performance by having a good radiation pattern and radiation gain.

[0073] As such, the RFID tag according to the present invention has good directivity and reading range and satisfies durability requirements, while simultaneously minimizing its size so that it can be embedded and used in various products. In addition, by processing the wire into a zigzag shape and directly inserting and assembling it into a substrate, the manufacturing process can be simplified compared to conventional helical wire antennas.

[0074] In addition, the RFID tag according to the present invention operates at a frequency in the ultra-high frequency (UHF) band to satisfy a long reading range and is formed in a small size (40mm X 3.0mm X 1.2mm), allowing it to be embedded in a tire. At this time, the brass-plated antenna can improve adhesion with the material of the rubber component of the tire, and by forming a through hole in the substrate, it is easy to integrate it with the tire. By inserting an RFID tag with excellent durability and electrical conductivity into the tire in this way, the stress continuously applied to the RFID tag can be relieved by the tag itself, thereby preventing fatigue failure of the RFID tag.

[0075] Although the present invention has been described above, those skilled in the art will recognize that the invention may be implemented in other forms while maintaining the technical concept and essential features of the invention.

[0076] The scope of the rights of the present invention shall be determined primarily by the claims; however, all modifications or variations derived from configurations directly derived from the descriptions in the claims, as well as configurations equivalent thereto, shall be interpreted as being included within the scope of the rights of the present invention.

Claims

1. Substrate; RFID chip mounted on the above substrate; A wire antenna assembled on the substrate and connected to each of the two terminals of the RFID chip; and It includes a central molding portion that encloses the connection portion between the RFID chip and the wire antenna, and An RFID tag characterized by having a loop-structured antenna pattern formed on the substrate that connects two terminals of an RFID chip.

2. In Paragraph 1, The above wire antenna is an RFID tag in which a conductive wire is formed in a zigzag shape.

3. In Paragraph 2, An RFID tag formed by plating the above conductive wire with brass one or more times.

4. In Paragraph 2, The above conductive wire is an RFID tag formed of high-strength metal.

5. In Paragraph 1, An RFID tag in which one end of the wire antenna is fixed to a first via hole formed at the leading end of the substrate, and the other end is fixed to a second via hole formed adjacent to the RFID chip.

6. In Paragraph 5, An RFID tag in which the second via hole is connected to one end terminal of the RFID chip via the first antenna pattern and connected to the other end terminal of the RFID chip via the second antenna pattern.

7. In Paragraph 6, An RFID tag in which the first antenna pattern is formed on the component surface of the substrate and the second antenna pattern is formed on the copper foil surface of the substrate.

8. In Paragraph 1, An RFID tag in which the antenna pattern of the above substrate is formed as a meander-shaped line.

9. In Paragraph 1, The above central molding part is an RFID tag that encloses the second via hole and the antenna pattern.

10. In Paragraph 1, The above central molding part is an RFID tag formed of epoxy material.

11. In Paragraph 1, The above substrate is an RFID tag including a substrate hole formed by penetrating a portion thereof.

12. In Paragraph 1, An RFID tag in which the resonant frequency of the above wire antenna and antenna pattern is formed at a frequency in the ultra-high frequency (UHF) band.

13. A tire comprising an RFID tag according to any one of claims 1 to 12.

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