Contactless communication medium and its resonance frequency adjustment method

Abstract

To provide a contactless communication medium that enables easy adjustment of resonant frequency according to carrier frequencies of reader / writer sides, even when an antenna is formed using a conductive wire, thereby ensuring stable information transmission and reception.SOLUTION: A contactless communication medium of the present invention includes: a support substrate; a circuit device having first and second connection terminals disposed on the support substrate; and a conductive pattern electrically connected to the circuit device. The conductive pattern includes a coil portion in which a conductive wire is spirally wound, and a loop portion formed of the conductive wire and disposed on the inner periphery of the coil portion. A first end of the conductive wire of the coil portion is connected to the first connection terminal of the circuit device, and a second end of the conductive wire of the coil portion is connected to the second connection terminal of the circuit device. First and second ends of the conductive wire of the loop portion are connected to one of the first and second connection terminals of the circuit device. At least a part of the conductive wire of the loop portion is parallel to the coil portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a contactless communication medium for transmitting and receiving information to and from a reader / writer in a contactless manner, and a method for adjusting the resonance frequency thereof. [Background technology]

[0002] Conventionally, a contactless communication medium has been known that includes an antenna made of a wire coil on a substrate, and an IC chip connected to the wire coil or an IC module in which the IC chip is modularized in any manner (see Patent Document 1). The contactless communication medium receives electromagnetic waves emitted by a reader / writer (R / W) and generates power from the electromagnetic waves to transmit and receive data to and from the reader / writer.

[0003] In order to stably transmit and receive information between a contactless communication medium and a reader / writer, it is desirable to match the frequencies used during communication as closely as possible. Generally, contactless communication media are manufactured by adjusting the resonant frequency of the contactless communication medium in accordance with the carrier frequency of the reader / writer. For example, Patent Document 2 discloses a method for adjusting the resonant frequency of a contactless IC card equipped with an antenna formed by winding a conductor in a coil by adding an adjustable capacitance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-103829 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-216089 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, a non-contact communication medium in which an antenna is formed using a conductive wire forms a resonant circuit whose basic configuration is mainly the capacitance (C) component inside the circuit device and the inductance (L) and resistance (R) components of the antenna. To ensure stable and good communication with a reader / writer, the antenna provided in the non-contact communication medium is required to have the characteristic of supplying current to the circuit device at low power.

[0006] As an index of the frequency characteristics of a resonant circuit, the Q value (sharpness of the frequency characteristics) is expressed by the following formula: Q = (1 / R) × √(L / C) It is said that a large Q value reduces circuit loss and provides stable communication characteristics, and specifically, it is said that it is good to reduce the resistance (R) component of the resonant circuit formed by the non-contact communication medium. In other words, non-contact communication media require the formation of a simple antenna pattern with a low resistance value, and antennas formed from conductive wires that can meet these requirements are preferred.

[0007] On the other hand, in a contactless communication medium, the capacitance (C) component inside the circuit device may vary between individual units or between manufacturing lots. Therefore, in order to maintain the resonant frequency (f=1 / (2π√(LC))) determined by the capacitance (C) component and the inductance (L) component at a predetermined value, it may be necessary to adjust the antenna characteristics during the manufacturing of the contactless communication medium.

[0008] In order to adjust the antenna characteristics, for example, in a conventional contactless communication medium such as that disclosed in the above-mentioned Patent Document 1, the resonant frequency is adjusted by increasing or decreasing the number of turns of the antenna or the spacing between the wires, thereby changing the inductance (L) component. However, by increasing or decreasing the number of turns of the antenna or the spacing between the wires, it is relatively difficult to fine-tune the resonant frequency, and the resistance (R) component may also change. Therefore, the Q value in the above-mentioned frequency characteristic equation also fluctuates, which may affect the communication status with the reader / writer.

[0009] Furthermore, in a conventional contactless communication medium, such as that disclosed in Patent Document 2, a specific resonant frequency adjustment method is to increase the capacitance (C) component by further winding a wire spirally around a coil, which serves as the base of the antenna. However, a hollow winding method is used to wind the wire spirally around the coil. More specifically, the antenna must be formed independently using a winding device. In other words, with the hollow winding method, after forming the desired antenna using the winding device, connecting the circuit device (IC chip) and securing it to the support substrate may be performed manually, and even if mechanization is possible, complex and expensive machinery may be required. Therefore, with this adjustment method, it is time-consuming to adjust the spiral portion to accommodate variations in the capacitance (C) component within the circuit device, which vary from one device to another and from one production lot to another. Furthermore, the resistance (R) component also changes depending on the amount of adjustment of the capacitance (C) component, which may affect the communication status with the reader / writer.

[0010] The present invention has been made in consideration of such problems, and aims to provide a non-contact communication medium and a method for adjusting the resonant frequency of a non-contact communication medium that can easily adjust the resonant frequency according to the carrier frequency on the reader / writer side, even when the antenna is formed from a conductor, and that can achieve stable transmission and reception of information. [Means for solving the problem]

[0011] The present invention provides a contactless communication medium including a support substrate, one or more circuit devices provided on the support substrate and having first and second connection terminal portions, and a conductive pattern formed by conductors and electrically connected to the circuit devices, the conductive pattern includes a coil portion in which a conductive wire is wound in a spiral shape, and one or more loop portions provided on the inner periphery of the coil portion and formed by the conductive wire; a first end of a conductor of the coil portion connected to the first connection terminal portion of the circuit device, and a second end of the conductor of the coil portion connected to the second connection terminal portion of the circuit device; the first and second ends of the conductor of the loop portion are connected to one of the first and second connection terminal portions of the circuit device; The non-contact communication medium is characterized in that at least a portion of the conductor of the loop portion is parallel to the coil portion.

[0012] In the non-contact communication medium of the present invention, when the conductor located on the innermost side of the spirally wound conductors in the coil portion is defined as an innermost conductor, It is preferable that a portion of the conductor of the loop portion parallel to the coil portion is located in an inner range extending from the innermost conductor to 2.0 mm in a direction perpendicular to the inner side of the extension direction of the innermost conductor.

[0013] In the non-contact communication medium of the present invention, when the length measured around the coil portion along the innermost conductor is defined as length L1, and the length measured along the portion of the conductor of the loop portion located in the innermost range and parallel to the coil portion is defined as length L2, it is preferable that length L2 is 2 to 98% of length L1.

[0014] In the contactless communication medium of the present invention, it is preferable that the conductive pattern is formed by one continuous conductive conductor made of a thin metal wire.

[0015] In the non-contact communication medium of the present invention, it is preferable that the conductive conductors constituting the conductive pattern are covered with a self-fusing insulating coating.

[0016] The present invention provides a method for adjusting a resonant frequency using the non-contact communication medium, comprising: The method for adjusting the resonant frequency includes a step of changing the length of a portion of the conductor of the loop portion that is parallel to the coil portion and / or its position from the coil portion. [Effects of the Invention]

[0017] According to the present invention, even when an antenna is formed using a conductor, it is possible to provide a non-contact communication medium and a method for adjusting the resonant frequency of the non-contact communication medium, which can easily adjust the frequency according to the carrier frequency on the reader / writer side and achieve stable transmission and reception of information. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic plan view showing an example of a contactless communication medium according to the present embodiment with an exterior body that can be provided on the surface of a support substrate removed. [Figure 2] 2 is a schematic cross-sectional view showing an example of a contactless communication medium according to the present embodiment, taken along line aa' in FIG. 1. FIG. [Figure 3] 2 is a schematic cross-sectional view taken along line aa' in FIG. 1, showing an example of a contactless communication medium according to the present embodiment in which an exterior body is provided on the surface of a support substrate. FIG. [Figure 4] FIG. 10 is a schematic plan view showing another example of a contactless communication medium according to the present embodiment, with an exterior body that can be provided on the surface of a support substrate removed. [Figure 5] 10 is a graph showing the relationship between the proportion of the loop portion parallel to the coil portion and the resonance frequency of the non-contact communication medium of the example and the comparative example. [Figure 6] 10 is a graph showing the relationship between the distance between the loop wire and the innermost wire of the coil and the resonant frequency. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail below, but the present invention is not limited to this embodiment. The contactless communication medium of the present embodiment is an information medium that can be used in an RFID (Radio Frequency Identification) system, and is collectively called an RF tag, RFID tag, or IC tag, and can be used as a contactless IC card, a smart car key, an IC passport, etc.

[0020] Here, an RFID system is an ID system that uses electromagnetic waves as a communication medium, and is composed of a contactless communication medium, which is an information medium, and an external device such as a reader / writer that reads and writes information to the contactless communication medium, and can update information through contactless communication.The contactless communication medium is equipped with a circuit device that has a memory area that is either dedicated to reading information or that can freely read and write information, and can operate using contactless power transmission from the reader / writer, allowing necessary information to be retrieved at any time and new information to be written as needed.

[0021] The main types of communication methods used in RFID systems are (1) electromagnetic coupling, which uses mutual induction between coils due to an alternating magnetic field, and (2) electromagnetic induction, which uses long- and medium-wave electromagnetic waves in the 13.56 MHz band. It is preferable that the non-contact communication medium of this embodiment is one that applies an electromagnetic induction method.In this case, an induced current is generated in the antenna coil due to electromagnetic waves emitted from the reader / writer, and when the frequency of this induced current matches a frequency that can induce a resonance phenomenon in the resonant circuit, the information processing unit of the circuit device can start processing data.

[0022] 1 is a schematic plan view showing an example of a contactless communication medium according to this embodiment with the exterior body on the surface of a support substrate removed. In this specification, the left-right direction in a plan view such as FIG. 1 is the width direction of the contactless communication medium, and the up-down direction is the height direction of the contactless communication medium. Furthermore, the front-back direction in a plan view such as FIG. 1 is the front-back direction (thickness direction) of the contactless communication medium, and the side on which the conductive pattern is provided with respect to the support substrate 1 is the front side (one side) of the front-back direction, and the opposite side is the back side (the other side) of the front-back direction.

[0023] The non-contact communication medium of this embodiment illustrated in Figure 1 comprises a support substrate 1, one or more circuit devices 2 having connection terminal portions 4 provided on the support substrate 1, and a conductive pattern 3 formed by a conductor and electrically connected to the circuit device 2. The conductive pattern 3 also includes a coil portion 31 in which a conductor wire is wound in a spiral shape, and one or more loop portions 32 formed by a conductor wire provided on the inner periphery of the coil portion 31. The coil portion 31 of the conductive pattern 3 can function as an antenna due to the spirally wound conductor wire, and the loop portion 32 has a closed loop pattern in at least one of the connection terminal portions 4 (both connection terminal portions 41, 42 in the example of FIG. 1) where the coil portion 31 connects to the circuit device 2. The contactless communication medium is capable of communicating with an external device (not shown) via the conductive pattern 3.

[0024] Hereinafter, each component of the contactless communication medium of this embodiment will be described in more detail. The support substrate 1 comprises at least one or more circuit devices 2 and conductive patterns 3 on its surface. The support substrate 1 has a predetermined thickness and is composed of a single layer or multiple layers, at least one of which can be composed of a resin material. It is desirable to use a thermoplastic resin as the resin material for at least one layer of the support substrate 1. More specifically, thermoplastic resins such as PETG (amorphous PET copolymer), PVC (polyvinyl chloride), PC (polycarbonate), PET (polyethylene terephthalate), expanded PET, PEN (polyethylene naphthalate), and ABS (acrylonitrile-butadiene-styrene copolymer synthetic resin) can be used. The thickness of the support substrate 1 is arbitrary, but can be, for example, 0.1 mm to 1.0 mm, or 0.1 mm to 0.5 mm. Examples of support substrates 1 composed of multiple layers include those in which a thermoplastic resin is coated on a veneer or paper substrate.

[0025] 1, the support substrate 1 is rectangular, but the shape can be any shape, such as circular, elliptical, polygonal, etc. When the contactless communication medium of this embodiment is used for a contactless IC card, the support substrate 1 is rectangular as in the illustrated example, and its size can be 85.47 to 85.72 mm in the width direction and 53.92 to 54.03 mm in the height direction.

[0026] The circuit device 2 is provided on the surface of the support substrate 1 and has an integrated circuit (IC) chip built in. The circuit device 2 is electrically connected to the conductive pattern 3 and includes a connection terminal portion 4 (first and second connection terminal portions 41, 42) for the connection. An IC chip generally includes a power supply circuit, a control circuit, a memory, and a transceiver circuit. The power supply circuit operates using power received via the coil portion 31 as a driving power source and supplies power to other circuit blocks. The transceiver circuit is a circuit that transmits and receives signals via the coil portion 31. The control circuit is coupled to the transceiver circuit and memory so as to be able to input and output signals, and mediates data transfer between the transceiver circuit and the memory. For example, the control circuit reads data from the memory in response to an input signal from the transceiver circuit and transfers it to the transceiver circuit, or writes data to the memory in response to an input signal from the transceiver circuit. As is clear from the above description, the circuit device 2 is capable of communicating with an external communication device (external device), typically a reader / writer, via the coil portion 31. In the illustrated example, one circuit device 2 is provided on the support substrate 1, but two or more may be provided. Also, as in the illustrated example, the circuit device 2 is disposed on the inner circumferential side of the coil portion 31 of the conductive pattern 3.

[0027] The conductive pattern 3 is provided on the surface of the support substrate 1 and is electrically connected to the circuit device 2. The conductive pattern 3 is formed of a conductor, and specifically includes a coil portion 31 in which the conductor is wound in a spiral shape, and one or more loop portions 32 provided on the inner periphery of the coil portion 31 and formed of the conductor. The coil portion 31 of the conductive pattern 3 can function as an antenna by using a conductor wound in a spiral shape. More specifically, the coil portion 31 has first and second ends of the conductor (one end of one conductor is the first end and the other end is the second end), with the first end connected to a first connection terminal portion 41 of the circuit device 2 and the second end connected to a second connection terminal portion 42 of the circuit device 2. The conductor forming the coil portion 31 is wound multiple times as shown in FIG. 1, forming a spiral shape as a whole (the wound portion of the conductor of the coil portion 31 is also referred to as the wound portion). In the illustrated example, the circuit device 2 is disposed on the inner circumferential side of the coil portion 31, and in this case, a first end of the conductor of the coil portion 31 is connected to a first connection terminal portion 41 of the circuit device 2 located on the inner circumferential side, and the conductor extends from the first connection terminal portion 41 to the outer circumferential side, then changes its extending direction and extends further to form a winding portion. After the conductor has been wound a desired number of times (after the winding portion has been formed), the conductor changes its extending direction to the inner circumferential side and extends to connect to a second connection terminal portion 42 of the circuit device 2.

[0028] In this embodiment, "the conductor is wound in a spiral shape" means that the conductor is wound around approximately the same center, and in this case, adjacent conductors may extend approximately parallel to each other. 1, the coil portion 31 is generally rectangular, but the shape may be any shape, such as circular, elliptical, polygonal, etc. In the illustrated example, the support substrate 1 is rectangular, and the coil portion 31 is provided in the vicinity of the outer edge of the support substrate 1 in the same rectangular shape as the support substrate 1, but the arrangement of the coil portion 31 may be arbitrary depending on, for example, the application of the contactless communication medium.

[0029] The conductor wire (circumferential portion) of the coil portion 31 is preferably arranged at a substantially uniform pitch as shown in Fig. 1, but the conductor wire can be arranged arbitrarily as long as it is spirally wound. When arranged at a substantially uniform pitch, the pitch is not particularly limited, and can be, for example, 0.1 to 3.0 mm, and preferably 0.2 to 1.0 mm. The number of turns of the conductor of the coil portion 31 can be set arbitrarily depending on the application of the non-contact communication medium.

[0030] 1, the loop portion 32 of the conductive pattern 3 is provided on the inner periphery side of the coil portion 31. In addition, both the first and second ends of the conductive wire of the loop portion 32 are connected to one of the first and second connection terminal portions 41, 42 of the circuit device 2. Specifically, loop portion 32 is located on the inner side of the conductor (circumferential portion) of coil portion 31. Furthermore, both the first end and the second end of the conductor of loop portion 32 are connected to at least one of connection terminal portions 4 at which coil portion 31 connects to circuit device 2 (in the example of FIG. 1 , one loop portion is provided at each of connection terminal portions 41 and 42). That is, for example, if the first end of loop portion 32 is the starting end and the second end is the ending end, the first end (starting end) of loop portion 32 is connected to one of connection terminal portions 4 of circuit device 2, the conductor extends in a region inner than the conductor (circumferential portion) of coil portion 31, and the second end (ending end) is connected to the one of connection terminal portions 4 of circuit device 2. In this way, loop portion 32 forms a closed loop pattern located within coil portion 31. In the illustrated example, the conductor of the loop portion 32 is arranged so as not to intersect with the conductor of the coil portion 31 .

[0031] 1 and other figures, at least a portion of the conductor of the loop portion 32 is parallel to the coil portion 31. More specifically, in the example of Fig. 1, two loop portions 32 are formed by the first connection terminal portion 41 and the second connection terminal portion 42 of the circuit device 2, and in each loop portion 32, the portion of the conductor on the widthwise center side (one side) is not parallel to the coil portion 31, while the portions of the conductor on both sides in the height direction (two sides) and on the outer side in the width direction (one side) are adjacent to and parallel to the coil portion 31.

[0032] As described above, in the non-contact communication medium of this embodiment, at least a portion of the conductor of the loop portion 32 is parallel to the coil portion 31, making it easy to adjust the resonant frequency according to the carrier frequency on the reader / writer side. Specifically, the loop portion 32 is provided on the inner periphery side of the coil portion 31, and at least a portion of the conductor of the loop portion 32 is parallel to the coil portion 31, thereby functioning to inhibit the inductance (L component) of the coil portion 31, the portion of which functions as an antenna. The degree to which the inductance of the coil portion 31 is inhibited can be changed by the degree to which the conductor of the loop portion 32 is parallel to the coil portion 31. Therefore, the inductance of the coil portion 31 can be adjusted by the arrangement of the loop portion 32, and the resonant frequency of the non-contact communication medium can also be adjusted. In this case, since the loop portion 32 is connected to one of the first and second connection terminal portions 41, 42 of the circuit device 2, it does not substantially affect the resistance (R component) of the antenna itself, and therefore does not substantially affect the frequency characteristics of the resonant circuit. Furthermore, as described above, the resonant frequency can be adjusted by changing the degree to which the conductor of the loop portion 32 is parallel to the coil portion 31, and this can be done without adjusting the shape of the coil portion 31 (changing the design such as the installation mode) or the circuit device 2. Therefore, in this embodiment, in a non-contact communication medium in which an antenna is formed by a conductor, it is possible to easily adjust the resonant frequency according to the carrier frequency on the reader / writer side without changing the shape of the coil portion 31, i.e., without changing the resistance (R component) of the antenna itself.

[0033] Here, in this embodiment, when a portion of the conductor of the loop portion 32 is parallel to the coil portion 31, it means that the portion is parallel to the conductor located on the innermost side of the conductor (circumferential portion) of the coil portion 31, with an inter-wire distance of 5.0 mm or less. More specifically, the phrase "a portion of the conductor in the loop portion 32 is parallel to the innermost conductor" means that the extending directions of the portion and a portion of the innermost conductor spaced apart in a direction perpendicular to the extending direction of the portion are substantially parallel, and the portion is spaced apart from the innermost conductor by up to 5.0 mm in a direction perpendicular to the extending direction of the portion. Here, "substantially parallel" means that the angle between the extending directions may be 2.5° or less, preferably 1.5° or less, and more preferably 0.5° or less.

[0034] Furthermore, in this embodiment, if a portion of the conductor of loop portion 32 that is parallel to coil portion 31 is located far away from coil portion 31 (particularly the innermost conductor), the effect of that portion inhibiting the inductance (L component) of coil portion 31 is reduced. Therefore, it is preferable that the portion of the conductor of loop portion 32 that is parallel to coil portion 31 is located within a range of a predetermined distance from the innermost conductor of coil portion 31, measured in a direction perpendicular to the inner side of the extension direction of the conductor (this range is also referred to as an inner range). Specifically, it is preferable that the portion of the conductor of the loop portion 32 that is parallel to the coil portion 31 is located within a range of up to 2.0 mm, more preferably up to 1.0 mm, from the innermost conductor measured in a direction perpendicular to the inner side of the extension direction of the innermost conductor. Alternatively, when the conductor of coil portion 31 is wound at a specific pitch, the portion of the conductor of loop portion 32 that is parallel to coil portion 31 is preferably located within a distance from the innermost conductor at a pitch that is 1.5 times the winding pitch of coil portion 31, measured in a direction perpendicular to the innermost conductor relative to the direction in which the innermost conductor extends, and more preferably within a distance equal to the winding pitch of coil portion 31. Most preferably, the portion of the conductor of loop portion 32 that is parallel to coil portion 31 is located at a pitch that is the same as the winding pitch of coil portion 31, measured from the innermost conductor in a direction perpendicular to the innermost conductor relative to the direction in which the innermost conductor extends (in this case, the inner range is a position that is the same pitch as the winding pitch of coil portion 31, measured from the innermost conductor in the direction in which the innermost conductor extends). The distance measured above is the distance measured from the center of the conductor at the starting point of the measurement to the center of the conductor at the end point.

[0035] In this embodiment, from the viewpoint of ease of adjusting the resonant frequency by the loop portion 32, it is preferable that the portion of the conductor of the loop portion 32 that is parallel to the coil portion 31 has a constant length. Specifically, when the length measured along the innermost conductor of the conductor (circumferential portion) of coil portion 31 is taken as length L1 (the length from X1 to X2 in Figure 1), and the length of the portion of loop portion 32 conductor located within the innermost range of the innermost conductor and parallel to the innermost conductor is taken as length L2, it is preferable that length L2 be 2 to 98% of length L1, more preferably 10 to 95%, and even more preferably 15 to 95%.

[0036] In the illustrated example, two loop portions 32 are formed at the first connection terminal portion 41 and the second connection terminal portion 42 of the circuit device 2, but in this embodiment, a loop portion 32 may be formed at only one of the first connection terminal portion 41 and the second connection terminal portion 42 of the circuit device 2. Also, in the illustrated example, one loop portion 32 is formed at each of the first connection terminal portion 41 and the second connection terminal portion 42 of the circuit device 2, but in this embodiment, multiple loop portions 32 may be formed at one connection terminal portion 41. In this embodiment, when multiple loop portions 32 are formed, it is preferable to arrange them so as to divide the space on the inner periphery of the coil portion 31 and so as not to overlap each other, as in the example shown in the figure.

[0037] In this embodiment, the conductive pattern 3 is preferably formed of a single continuous conductive wire made of thin metal wire, as shown in Fig. 1 etc. Specifically, it is preferable that the conductive wire of the coil portion 31 and the conductive wire of the loop portion 32 are a single continuous conductive wire made of thin metal wire. In this way, the conductive pattern 3 is formed from a single continuous conductor made of a thin metal wire, which facilitates the formation of the conductive pattern 3 during the manufacture of the contactless communication medium. Also, as shown in Fig. 1, the conductor winds around the connection terminal 4 of the circuit device 2 where the loop portion 32 is formed, which improves the connectivity between the connection terminal 4 of the circuit device 2 and the conductor.

[0038] A case in which the conductive pattern 3 is formed by one continuous conductor made of a thin metal wire will be described using an example in which there are two loop portions 32 as in the example of Figure 1. A first end of the conductor of the coil portion 31 and a first end of the conductor of the loop portion 32 are connected at a first connection terminal portion 41 of the circuit device 2, and a second end of the conductor of the coil portion 31 and a first end of the conductor of the loop portion 32 are connected at a second connection terminal portion 42 of the circuit device 2. The loop portions 32 extend continuously from both ends of the coil portion 31 and are arranged on the inner periphery of the coil portion 31, at least a portion of which is parallel to (adjacent to) the coil portion 31, forming a loop shape. Therefore, the ends of this single conductor become the second end of the conductor of the loop portion 32 on the first connection terminal portion 41 side of the circuit device 2, and the second end of the conductor of the loop portion 32 on the second connection terminal portion 42 side of the circuit device 2.

[0039] As shown in the illustrated example, the tips of the ends of the conductor wires may extend beyond the first and second connection terminal portions 41, 42 of the circuit device 2. This can improve the connectivity between the connection terminal portions 4 of the circuit device 2 and the conductor wires.

[0040] 1, two loop portions 32 are provided, and the two loop portions 32 are arranged so that the loop portion 32 is parallel to substantially the entire innermost conductor of the coil portion 31. In this embodiment, instead of this, as shown in FIGS. 4(a) to 4(c), the shape of the loop portion 32 can be adjusted so that the length parallel to the innermost conductor of the coil portion 31 is reduced.

[0041] The conductors of the conductive pattern 3 can be formed by printing with conductive ink such as silver paste or by etching metal foil such as copper foil, but can also be formed using conductive wire that is, for example, circular in cross section. In this embodiment, it is preferable to use a wire because the coil portion 31 and the loop portion 32 can be easily formed as one continuous line.

[0042] When the conductive pattern 3 is formed of wire, the wire includes at least a conductor, preferably a conductor coated with a self-adhesive insulating coating. The conductor is, for example, a metal wire such as copper wire, iron wire, or gold wire, but other materials can be used as long as they are conductive. From the viewpoint of low electrical resistance and cost, it is preferable to use copper wire as the conductor. The insulating coating that coats the conductor is an insulating resin coating, and the conductor coated with the insulating coating can be a commercially available enameled wire. Specific examples of insulating resin coatings include polyester, polyethylene, polyurethane, polyvinyl chloride, polyamide, polyimide, polyesterimide, polyamideimide, and fluororesin. Furthermore, the material of the conductor wire of the coil portion 31 and the material of the conductor wire of the loop portion 32 may be different.

[0043] The width (diameter in the case of wires) of the conductive wires constituting the conductive pattern 3 in plan view is not particularly limited, but can be, for example, 0.05 mm to 0.50 mm, or 0.05 mm to 0.20 mm. From the viewpoints of electrical resistance value and ease of pattern formation, it is more preferably 0.10 mm to 0.15 mm.

[0044] Furthermore, as illustrated in FIG. 3, the non-contact communication medium of this embodiment can include an exterior body 5 that is disposed on the support substrate 1 and covers its entire surface. The exterior body 5 can be made of the same resin as the resin that forms the support substrate 1, i.e., the thermoplastic resin described above. If a different resin is used, warping may occur in the non-contact communication medium, but by using the same resin, this warping can be prevented and adhesion between layers can be improved. However, the resin of the exterior body 5 can also be a resin different from the resin that forms the support substrate 1. Here, the term "same resin" means that the type of resin is the same, and it is not necessary that the resin structure be exactly the same, but it is more preferable that the resin structure be the same.

[0045] Next, an example of a method for manufacturing the non-contact communication medium of this embodiment will be described. First, a support substrate 1 is prepared, and a through-hole or recess-like void 11 for arranging the circuit device 2 is provided at a position on the support substrate 1 where the circuit device 2 is to be arranged. Next, the circuit device 2 is arranged in the void 11 of the support substrate 1, and a conductive pattern 3 having a coil portion 31 and a loop portion 32 is wired on the surface of the support substrate 1.

[0046] Here, specific wiring methods are not particularly limited, but for example, when a wire is used as the conductor, the principle of ultrasonic fusion can be utilized to embed the wire into one surface of the support substrate 1. More specifically, for example, a wiring drawing device or the like can be used to feed the wire while applying ultrasonic waves to the wire, and the wire can be brought into contact with one surface of the support substrate 1 to melt the resin, thereby embedding the wire in a predetermined shape in the support substrate 1. Such a wiring drawing device can be equipped with an ultrasonic head, and can apply vibrations (ultrasonic waves, etc.) to the wire while feeding it out onto the surface of the support substrate 1, and simultaneously apply pressure (to push the wire into the resin) to embed the wire.

[0047] When ultrasonic fusion is used as the wiring method, the coil portion 31 or loop portion 32 of the conductive pattern 3 can be formed as follows. First, the conductor is placed or embedded from above the connection terminal 4 of the circuit device 2, which is the starting point of the tip of the conductor, near the connection terminal 4, to form a desired pattern. Next, after the desired pattern is formed, the conductor is placed or embedded up to the connection terminal 4 of the circuit device 2, which is the ending point.

[0048] When the conductive pattern 3 is formed of a single continuous conductor, it is preferable to form the loop portion 32 first, followed by the coil portion 31, when the loop portion 32 is formed at the connection terminal portion 4 of the circuit device 2 that is the starting point side of the conductive pattern 3. It is also preferable to form the coil portion 31 first, followed by the loop portion 32, when the loop portion 32 is formed at the connection terminal portion 4 of the circuit device 2 that is the ending point side of the conductive pattern 3. In this way, the conductive pattern 3 can be easily formed.

[0049] Next, in the cavity 11, the ends of the coil portion 31 and the loop portion 32 are electrically connected to the connection terminal portions 4 of the circuit device 2. Here, the electrical connection can be achieved via solder, which is a typical example of a conductive material. Note that FIG. 2 is a schematic cross-sectional view showing the contactless communication medium formed in this manner, taken along line a-a' in FIG.

[0050] Regarding the wiring method, as mentioned above, the conductor wires can also be formed by printing using conductive ink such as silver paste or by etching metal foil such as copper foil, and in this case, they can be formed by any known technique without any particular limitations.

[0051] Thereafter, if the non-contact communication medium includes an exterior body 5, the exterior body 5 is laminated on the surface of the support substrate 1. The exterior body 5 can be sufficiently adhered to the support substrate 1 and bonded by performing a heat treatment and / or a press treatment. For bonding, an adhesive layer, a pressure-sensitive adhesive layer, a heat seal layer, or the like may be interposed between the support substrate 1 and the exterior body 5, as necessary. Note that FIG. 3 is a schematic cross-sectional view of the non-contact communication medium formed in this manner, taken along line a-a' in FIG.

[0052] Each of the above steps can be performed on a sheet-like material that can be used to manufacture multiple contactless communication media at once, and by cutting the sheet into the desired shape after each step, multiple contactless communication media such as contactless IC cards can be manufactured. The specific method for cutting the sheet is arbitrary, and for example, punching with a die, rotary blade, cutting wire, laser, etc. can be used.

[0053] Next, a method for adjusting the resonance frequency using the non-contact communication medium of this embodiment will be described. In this embodiment, the adjustment of the resonant frequency can be performed during the process of manufacturing the above-mentioned non-contact communication medium, and the adjustment method of this embodiment includes a step of changing the length and / or position from the coil portion of a portion of the conductor of the loop portion that is parallel to the coil portion.

[0054] Specifically, when placing the circuit device 2 on the support substrate 1, the capacitance (C) component inside the circuit device 2 to be placed is measured. Next, the difference between the intended capacitance (C) component inside the circuit device 2 at the time of designing the non-contact communication medium and the actually measured capacitance (C) component inside the circuit device 2 is calculated. Then, the length of a portion of the conductor of the loop portion 32 parallel to the coil portion 31 and / or its position from the coil portion 31 is changed so that the inductance (L) component of the coil portion 31 changes by an amount equivalent to the change in the capacitance (C) component. When adjusting the conductor of the loop portion 32, it is preferable to measure in advance the amount of change in the inductance (L) component of the coil portion 31 when the length of a portion of the conductor of the loop portion 32 that is parallel to the coil portion 31 and / or its position from the coil portion 31 is changed, which allows the loop portion 32 to be adjusted quickly.

[0055] As described above, in the non-contact communication medium of this embodiment, the resonance frequency can be easily adjusted without changing the shape of the coil portion 31. The range of the change in inductance (L) component of the coil portion 31 that can be adjusted by changing the loop portion 32 can be roughly determined by the design of the conductive pattern 3. If there is a large difference between the intended capacitance (C) component inside the circuit device 2 when designing the non-contact communication medium and the actually measured capacitance (C) component inside the circuit device 2 and the difference is difficult to adjust by changing the loop portion 32, this can be done by changing, for example, the shape of the coil portion 31, specifically the number of turns of the conductor wire of the coil portion 31.

[0056] The above describes an embodiment of the present invention with reference to the drawings, but the non-contact communication medium of the present invention is not limited to the above example, and appropriate modifications can be made to the non-contact communication medium of the present invention. [Example]

[0057] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way. The following non-contact communication media were fabricated as examples and comparative examples, and their performance was evaluated.

[0058] <Test 1> Example 1 A recess (void) for accommodating the circuit device was provided in a thermoplastic resin sheet (Diafix PETG sheet, PG-WHI-FG, manufactured by Mitsubishi Chemical Corporation, thickness 0.30 mm) which served as the support substrate, and the circuit device (MOA4 manufactured by NXP) was housed therein. A wire (self-adhesive coated conductor wire, AB15φ0.10 mm, manufactured by ELEKTRISOLA) was embedded as a conductor using a wiring drawing device (WCE150 manufactured by Ruhlamat, settings: USP1200, speed: 40%) equipped with an ultrasonic head, to form a conductive pattern as shown in Figure 1 (the number of turns of the coil part of the conductive pattern in Example 1 is different from that in Figure 1).

[0059] More specifically, the circuit device was positioned at the center of the width of the support substrate, at a distance of 1 / 4 of the height from the top edge. The wire was a copper conductor covered with a self-adhesive urethane resin, and the conductive pattern was formed from a single wire. The conductive pattern further included a coil portion and one loop portion at each of the first and second connection terminals of the circuit device.

[0060] The conductive pattern was formed by embedding the wire from the vicinity of the first connection terminal of the circuit device, passing over the first connection terminal to form a loop, then passing over the first connection terminal again and spirally winding from the inner periphery to form a coil. After forming the coil, the wire was embedded over the wire that wound from the outermost periphery to the inner periphery, and then passed over the second connection terminal of the circuit device to form another loop, and then passed over the second connection terminal again to end near the second connection terminal.

[0061] The coil part of the conductive pattern had a width of 78 mm on the outermost side, a height of 42 mm, a line spacing (pitch) of 0.5 mm, and 5 turns. The wires of the two loop parts were adjacent to the wire on the innermost side of the coil part with a line spacing (distance between the centers of the conductors) p1 and p2 of 0.5 mm, and were generally parallel (see Figure 1). The wires were fixed to the connection terminals by soldering.

[0062] Examples 2 to 4 In Examples 2 to 4, non-contact communication media were manufactured in the same manner as in Example 1, except that the loop portions had shapes as shown in Figures 4(a) to 4(c) (Examples 2 to 4 differ from each other in the number of turns of the coil portion of the conductive pattern in Figures 4(a) to 4(c)). Specifically, in Example 2 having a loop portion as shown in Figure 4(a), one loop portion 33 is approximately half the size of Example 1, while in Example 3 having a loop portion as shown in Figure 4(b), both loop portions 34 are approximately half the size of Example 1, and furthermore, in Example 3 having a loop portion as shown in Figure 4(c), one loop portion 35 is smaller than Example 1, and the other loop portion is approximately half the size of Example 1.

[0063] (Comparative Example 1) In Comparative Example 1, a non-contact communication medium was manufactured in the same manner as in Example 1, except that no loop portion was formed.

[0064] As described above, the length L1 of one circumference of the coil portion along the innermost conductor and the length L2 of the portion of the loop portion parallel to the coil portion were measured for the non-contact communication media of Examples 1 to 4 and Comparative Example 1, in which the ratio of the length of the loop portion parallel to the innermost conductor of the coil portion was changed. The ratios of length L2 to length L1 (parallel ratios) for Examples 1 to 4 and Comparative Example 1 are shown in Table 1 below.

[0065] The non-contact communication media of Examples 1 to 4 and Comparative Example 1 prepared as described above were evaluated by measuring the values of resonance frequency (f), inductance (L), and resistance (R).

[0066] The resonant frequency was measured using a network analyzer R3753 manufactured by Advantest Corporation, with the non-contact communication medium placed on a measurement base (height 25 mm) so as to be parallel to the antenna surface on the network analyzer side.

[0067] The inductance (L) was measured using an LCR meter 4285A manufactured by Keysight Technologies, Inc., by placing the measurement probe on the connection terminal before the support substrate and outer casing were integrated.

[0068] Regarding the resistance (R), a milliohm high tester 3227 manufactured by Hioki E.E. Corporation was used to measure the DC resistance value by applying a measurement probe to the connection terminal before the holding substrate and the outer casing were integrated.

[0069] The results of the above evaluations are shown in Table 1 below. [Table 1]

[0070] FIG. 5 is a graph showing the change in resonant frequency relative to the ratio of the loop portion that is parallel to the coil portion (represented as "parallel ratio" in the graph). From Table 1 and FIG. 5, it can be seen that the resonant frequency changes without changing the resistance depending on the ratio of the loop portion to the coil portion.

[0071] <Test 2> For the non-contact communication medium of Example 1, the resonant frequency was measured when the distances p1 and p2 between the two loop portions and the innermost wire of the coil portion were changed from 0.25 mm to 10.0 mm. The results are shown in Figure 6. The results in Figure 6 show that the resonant frequency can be changed significantly when the distances p1 and p2 between the two loop portions and the innermost wire of the coil portion are set within a range of up to 2.0 mm.

[0072] From the above, it has been suggested that according to the present invention, by changing the ratio of the loop portion that is parallel to the coil portion, it is possible to easily adjust the resonant frequency in accordance with the resonant frequency of the reader / writer without changing the resistance (R) component of the antenna itself. [Industrial Applicability]

[0073] According to the present invention, even when an antenna is formed using a conductor, it is easy to adjust the resonant frequency according to the resonant frequency of the reader / writer side, and it is possible to provide a non-contact communication medium and a method for adjusting the resonant frequency of the non-contact communication medium that can achieve stable transmission and reception of information. [Explanation of symbols]

[0074] 1: Support substrate 2:Circuit device 3: Conductive pattern 31: Coil section 32, 33, 34, 35: Loop section 4: Connection terminal 41: First connection terminal portion 42: Second connection terminal portion 5: Exterior body 11: Void in the support substrate

Claims

1. A contactless communication medium comprising: a support substrate; one or more circuit devices provided on the support substrate and having first and second connection terminal portions; and a conductive pattern formed by conductors and electrically connected to the circuit devices, the conductive pattern includes a coil portion in which a conductive wire is wound in a spiral shape, and one or more loop portions provided on the inner periphery of the coil portion and formed by the conductive wire; a first end of a conductor of the coil portion connected to the first connection terminal portion of the circuit device, and a second end of the conductor of the coil portion connected to the second connection terminal portion of the circuit device; a first end and a second end of the conductor of the loop portion connected to one of the first and second connection terminal portions of the circuit device; A non-contact communication medium, characterized in that at least a portion of the conductor of the loop portion is parallel to the coil portion.

2. When the conductor wire located on the innermost side among the conductor wires wound in a spiral shape in the coil portion is defined as the innermost conductor wire, A non-contact communication medium as described in claim 1, wherein a portion of the conductor of the loop portion parallel to the coil portion is located in an inner range extending from the innermost conductor to 2.0 mm in a direction perpendicular to the inner side of the extension direction of the innermost conductor.

3. The non-contact communication medium according to claim 2, wherein length L2 is 2 to 98% of length L1, where length L1 is the length measured around the coil portion along the innermost conductor, and length L2 is the length measured along the portion of the conductor of the loop portion located in the inner range that is parallel to the coil portion.

4. 3. The contactless communication medium according to claim 1, wherein the conductive pattern is formed by a single continuous conductive conductor made of a thin metal wire.

5. 3. The non-contact communication medium according to claim 1, wherein the conductive conductors constituting the conductive pattern are covered with a self-fusing insulating coating.

6. A method for adjusting a resonance frequency using the non-contact communication medium according to claim 1 or 2, comprising: A method for adjusting a resonant frequency, comprising the step of changing the length of a portion of the conductor of the loop portion parallel to the coil portion and / or its position from the coil portion.

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