JP2013152600A - Rfid tag system and rfid package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an RFID tag system that realizes a longer communication distance compared to a single small RFID tag, and has high degree of freedom of adaptation because of the ability of using a metal component or a metal product itself being an attachment object of the RFID tag as a conductor to form a slit being a part of the RFID system; and an RFID package used for the RFID tag system.SOLUTION: An RFID tag system includes: an RFID package including an IC chip, an antenna that is connected with the IC chip to form an electric closed circuit, and a sealant that seals the IC chip and the antenna, and having the longitudinal, lateral, and height size relative to an operation wavelength of the IC chip of 1/50 or smaller; and a conductor including a slit having the RFID package arranged inside or a periphery thereof.

Description

  The present invention relates to an RFID (Radio Frequency Identification) tag system and an RFID package that can be used in combination with a general-purpose reader or reader / writer to exchange information without contact.

  For the purpose of product information, identification, management and anti-counterfeiting, many non-contact RFID tags (hereinafter simply referred to as “RFID tags”) equipped with IC chips are used for products, packaging, cards, documents and the like. Yes. Information such as the product name and price is written on the IC chip. When managing, selling, and using the reader, a reader or a reader / writer (hereinafter, the reader and the reader / writer may be collectively referred to as “reader”). )), The information of these IC chips can be read and used wirelessly. Some information such as the date of manufacture, the factory, and the balance can be written later by a reader / writer. In this way, the RFID tag brings great advantages such as improved convenience of product management, improved safety, and elimination of human error.

  RFID tags are strongly demanded to be small and thin due to the nature of being attached to a product or built in a card. In particular, in recent years, it has been attracting attention as a use for things that have been conventionally managed by engraving and entering lot numbers, or where management itself has not been possible. Specifically, glasses, watches, medical samples, semiconductor packages, etc. (hereinafter referred to as “small, multi-product”) This is useful for managing the product (sample) factory, workers, date of manufacture, materials used, dimensions, characteristics, inventory quantity, etc., reducing the labor of management workers and preventing mistakes. be able to. In order to realize such a convenient management system, it is indispensable to make the RFID tag smaller and thinner.

  As a relatively small and thin RFID tag, an RFID tag 80 in which an antenna 20 is formed on a film substrate 1 and an IC chip 30 is mounted is disclosed as shown in FIG. ). In addition, as a smaller RFID tag, an antenna pattern and an IC chip are mounted on a substrate and then sealed and packaged (Patent Document 3), or a substrate is not provided to make it thinner and flatter. An IC chip is mounted on an independent antenna pattern and then sealed and packaged (Patent Document 4). Hereinafter, the RFID tag packaged in this way is referred to as an “RFID package”. Further, as shown in FIG. 2, an RFID package 80 downsized to an IC chip size is disclosed in which an antenna 20 is directly formed on an IC chip 30 (on-chip antenna) (Patent Documents 5 and 6). .

JP 2006-221211 A JP 2011-103060 A JP 2010-152449 A JP 2001-052137 A International Publication No. 2005/024949 JP 2007-189499 A

  The RFID tags of the cited documents 1 and 2 are relatively small and thin, and even a general-purpose reader or the like has a communication distance of 200 mm or more. However, as the antenna provided on the film base, the vertical or horizontal size is required to be about several centimeters, so the target to which the RFID tag is attached cannot be handled when the above-described small and multi-product is used. There are significant restrictions on the product and installation.

  The RFID tags of Cited Documents 3 and 4 are as small as several mm square (vertical: several mm × horizontal: several mm; the same applies hereinafter), and can be used for small multi-product types. However, since the RFID tag of the cited document 3 is provided with antennas in multiple layers, the substrate on which the antennas are provided requires a multilayer structure, which is costly and increases the overall thickness. The RFID tag of the cited document 4 uses a lead frame-like member in which a large number of single antennas that are not supported by the base material are connected. Therefore, when the individual RFID tag is cut into individual packages after sealing, the cut surface of the antenna is outside the package. There is concern about the impact on communication characteristics and reliability due to exposure and environmental degradation. Moreover, RFID tags having a size of about several millimeters square as in the cited documents 3 and 4 generally have a communication distance of about several millimeters or less, and cannot be said to be practically sufficient. Although it is possible to increase the communication distance by handling on the side of the reader or the like, there is a problem that usability is poor because a dedicated reader or the like is required and a general-purpose reader or the like cannot be used.

  The RFID tags of Cited Documents 5 and 6 have the same size as an IC chip (about several hundred μm square), and can sufficiently cope with small and wide variety products. However, the communication distance is 1 mm or less or as short as the contact level, and there is a problem that work efficiency and flexibility are low in the actual use site. On the other hand, when trying to increase the communication distance, it is necessary to increase the size of the IC chip itself, which increases the cost.

  If the RFID tag has a size of about 10 mm square or less and a communication distance of about 10 mm or more, the application range will be greatly expanded, including small and multi-product types, and it can also be used with general-purpose readers. Therefore, the industrial utility value is very high. However, as described above, the RFID tag having a size of several mm square or less is short in communication distance and practically unusable.

  The present invention has been made in view of the above problems, and realizes a long communication distance as compared with a single small RFID tag. Moreover, a metal part or a metal product itself to which an RFID tag is attached can be used as an RFID tag. An object of the present invention is to provide an RFID tag system having a high degree of flexibility and an RFID package used therefor, which can also be used as a conductor forming a slit which is a part of the system.

The present invention relates to the following.
1. An IC chip, an antenna connected to the IC chip to form an electrical closed circuit, and the IC chip and a sealing material for sealing the antenna, and the vertical and horizontal directions with respect to the operating wavelength of the IC chip. An RFID tag system comprising: an RFID package having a height size of 1/50 or less; and a conductor having a slit disposed inside or around the RFID package.
2. Item 2. The RFID tag system according to Item 1, wherein the antenna of the RFID package is a single layer coil.
3. Item 3. The RFID tag system according to item 1 or 2, wherein the conductor is mainly composed of copper, aluminum, or iron.
4). Item 4. The RFID tag system according to any one of Items 1 to 3, wherein the conductor is a metal part or metal product, or a part of the metal part or metal product to which the RFID package is attached.
5. Item 5. The RFID tag system according to any one of Items 1 to 4, wherein the conductor slit is formed by any one of cutting, pressing, powder metallurgy, welding, and casting.
6). Item 6. The RFID tag system according to any one of Items 1 to 5, wherein the surface of the conductor is covered with an insulating material.
7). Item 7. The RFID tag system according to any one of Items 1 to 6, wherein the slit provided in the conductor has a substantially linear shape, a substantially U-shape, or a substantially meander line shape.
8). Item 8. The RFID tag system according to any one of Items 1 to 7, wherein the length of the slit is approximately ½ of the operating wavelength of the IC chip.
9. Item 8. The RFID tag system according to any one of Items 1 to 7, wherein one of both ends of the slit is an open end, and the length of the slit is approximately ¼ of the operating wavelength of the IC chip.
10. Item 12. The RFID tag system according to Items 1 to 9, wherein the operating frequency of the IC chip is between 0.86 and 0.96 GHz.
11. Item 10. The RFID package according to any one of Items 1 to 10, wherein the RFID package is embedded in a resin screw, a screw hole is formed in a part of a slit provided in a conductor, and the screw is screwed to a part of the slit. Thus, the RFID tag system in which the RFID package is disposed inside or around the slit.
12 In any one of Items 1 to 10, the RFID package is embedded in a resin-made crimp pin, and the RFID package is disposed in or around the slit by press-fitting the crimp pin into a part of the slit. RFID tag system.
13. Item 15. The RFID tag system according to any one of Items 1 to 12, wherein the size of the RFID package is 2.5 mm or less x 2.5 mm or less x 1.0 mm or less in height.
14 1. An RFID package used in any one of RFID tag systems 1 to 13, comprising an IC chip, an antenna connected to the IC chip to form an electrical closed circuit, and a sealing for sealing the IC chip and the antenna An RFID package having a length, width, and height of 1/50 or less with respect to the operating wavelength of the IC chip.

  The present invention has been made in view of the above problems, and realizes a longer communication distance than a small RFID tag alone, and forms a slit in a metal part or metal product itself to which the RFID tag is attached. It is an object of the present invention to provide an RFID tag system having a high degree of flexibility and an RFID package used therefor that can also be used as a conductor.

It is a schematic sectional view of a conventional RFID package. FIG. 10 is a schematic cross-sectional view of another conventional RFID package. It is a schematic plan view which shows the shape of the antenna of the RFID package of this invention. It is a schematic sectional drawing of an example of the RFID package of this invention. It is a figure which shows the electrical equivalent circuit of the coil antenna which connected IC chip. 1A is a schematic plan view of an RFID tag system of the present invention, and FIG. 1 is a schematic plan view of an RFID tag system of the present invention. 1 is a schematic plan view of an RFID tag system of the present invention. 1 is a schematic plan view of an RFID tag system of the present invention.

  The RFID package in the present invention refers to an RFID tag in which an IC chip and an antenna provided on a substrate are connected by wire bonding or the like and are sealed with a sealing material. An example of an embodiment of an RFID package used in the present invention is shown below.

  The base material in the RFID package supports an antenna and an IC chip. As the substrate, a resin is used. As a resin base material, it has heat resistance and mechanical strength of about several seconds at 250 to 300 ° C., which are necessary when exposed to heat during reflow or molding, or heat generated during use, and has a low coefficient of thermal expansion. Materials are preferred, and as such, glass epoxy, phenol, polyimide, etc. can be used. In order to form an antenna at low cost and without variation, it is effective to form an antenna by etching using a base material with a metal foil in which a metal foil is bonded to one side of the base material. Furthermore, it is effective to use a thin base material of about 10 to 50 μm for thinning the RFID package. As a base material that satisfies the above conditions, a polyimide base material with a copper foil in which a copper foil is bonded to one side of a polyimide base material (for example, product name: MCF-5000I, manufactured by Hitachi Chemical Co., Ltd., polyimide thickness 25 μm, copper foil thickness 18 μm) ) Is available. The relative permittivity is about 4.6 to 7.0 for paper phenol, about 4.4 to 5.2 for glass epoxy, and about 3.5 for polyimide, and all of these base materials can be used. If the relative dielectric constant is high, the inductance increases, and the antenna can be downsized. The relative dielectric constant is smaller than that of paper phenol or glass epoxy, but the substrate can be formed thin, heat resistant, strong physical strength, and good antenna formability. It is desirable to use materials.

  The antenna is electromagnetically coupled to a reader or the like, receives electric power, transmits it to the IC chip, and operates the IC chip. Since the antenna may be a single layer and does not need to be multi-layered, it should be formed at low cost and without variation when it is formed using a copper foil with a copper foil bonded to one side of the base material. This is desirable because

  As shown in FIG. 3, the IC chip 30 is disposed at the center of the resin base material 1, and the antenna 20 is disposed on one surface of the base material 1 on the outer periphery of the IC chip 30. Since the antenna 20 is arranged in a region where the length of the outer peripheral portion of the substrate 1 can be taken, the degree of freedom of the antenna shape is expanded and formed including the inductance L of the antenna 20 and the electrostatic capacitance C of the IC chip 30. It is easy to adjust the resonance frequency of the electric circuit (hereinafter also referred to as “LC resonance circuit”). In addition, since the antenna 20 is provided on the outer peripheral portion of the IC chip 30, in the case of a coil antenna, the diameter of the coil increases and the inductance increases, which is advantageous for securing a communication distance and reducing the size. The antenna 20 is connected to the IC chip 30 to form an electrical closed circuit so as not to have an open end. Here, forming an electrical closed circuit and not forming an open end means that the antenna 20 has two end portions, and these two end portions and two electrodes of the IC chip 30 (not shown). And are connected to each other. The end of the antenna 20 refers to a region within 1 mm from the end of the antenna 20. A specific example of an antenna that is connected to the IC chip 30 to form an electrically closed circuit and does not have an open end is the coil antenna of FIG. 3. Since the antenna 20 can be easily designed and an inductance can be efficiently obtained with a small area, it is advantageous to secure a communication distance.

  The shape of the antenna is shown in FIG. The shape of the antenna 20 is such that the resonance frequency of the electric circuit (LC resonance circuit) formed including the inductance of the antenna 20 and the capacitance of the IC chip 30 is at or near the operating frequency of the IC chip 30. design. As the shape of the antenna 20, a coil antenna or the like can be used. The coil antenna that is connected to the IC chip 30 to form an electrical closed circuit can be easily designed as an LC resonance circuit and can be efficiently obtained in a small area. It is desirable in that it can be done. A design method of the antenna 20 will be described later. In the case of a coil antenna, it is possible to mount the winding coil with an adhesive or the like, but the coil produced by etching is more stable in performance than the winding coil, and the conductor width / between the conductors Since it is possible to form a fine wiring having a distance of about 0.2 mm / 0.2 mm to 0.05 mm / 0.05 mm, it is advantageous for downsizing and is excellent in mass productivity. Industrially effective.

  FIG. 3 also shows the IC chip 30 and the wire 40 bonded by wire bonding. When the antenna 20 is formed by etching the copper foil of polyimide with copper foil, the IC chip 30 is formed by leaving the copper foil of the portion where the IC chip 30 is mounted and forming a die pad (not shown). In connection, such as wire bonding, rigidity is maintained and yield is improved. A die-bonding film (not shown) is disposed on the copper foil where the IC chip 30 is mounted, and the IC chip 30 is fixed thereon. Although the IC chip 30 may be read-only, it is preferable that information can be written because work history and the like can be written at any time. Thereafter, the IC chip 30 and the antenna 20 are directly connected by wire bonding. In the coil antenna 20 of FIG. 3, two antenna end portions are located with the antenna 20 in between, and the antenna end portion and the IC chip are sandwiched between the antenna 20 located between them by the wire 40 of wire bonding. By directly connecting to 30, it is not necessary to provide a jumper line or to connect it via multiple through holes. Therefore, the cost can be reduced.

  The antenna can be directly connected to the IC chip by flip chip connection by adjusting the wiring location. Either a multilayer wiring using a double-sided copper foil base material or a single-layer wiring using a single-sided copper foil base material can be used. When multilayer wiring is performed using a double-sided copper foil base material or the like, the diameter of the coil can be reduced, so that the vertical and horizontal dimensions of the RFID package can be reduced, and downsizing of the vertical and horizontal sizes can be easily realized. However, in this case, there are disadvantages such as an increase in height dimension, a decrease in mass productivity and a cost increase, and further, the wiring is exposed to the surface only by sealing one side. . For this reason, it is desirable to reduce the vertical and horizontal dimensions of the RFID package by forming a single-layer coil antenna using a single-sided copper foil base material, and to realize downsizing of the vertical and horizontal sizes.

  FIG. 4 is a cross-sectional view showing the RFID package 80 formed into a substantially rectangular parallelepiped shape by dicing after being sealed with a sealing material. The IC chip 30, the antenna 20, and the wire 40 mounted on the die pad 90 on the base material 1 are collectively sealed using the sealing material 10 to protect them. Since a thin material is used as the base material 1 and the antenna 20 is provided as a single layer only on one side of the base material, the thickness (height) after sealing is, for example, about 0.2 to 1.0 mm. it can. After sealing, all the metal wiring parts such as the IC chip 30, the antenna 20, and the wire 40 are sealed, so that the structure cannot be touched at all from the outside of the sealing material 10. Safety and reliability are also improved from the viewpoint.

  As a sealing material, the sealing material normally used with the semiconductor can be used, and a dielectric constant is about 2.6-4.5. In order to improve the performance of the RDID package itself, it is preferable that the relative permittivity of the sealing material is low. However, if the relative permittivity is high, the inductance increases, so that the antenna can be downsized.

  The RFID package manufactured in this manner has a base material with a heat resistance of 180 ° C. or higher, a sealing material with a heat resistance of 150 ° C. or higher, and uses wire bonding. Therefore, an antenna is formed on a conventional PET or the like. It has higher heat resistance than RFID tags, and operates normally even at high temperatures. For this reason, when the applied product is an electronic component such as a semiconductor package or an injection molded product, it is exposed to heat during reflow, molding, or heat generation during use, and therefore requires heat resistance of about several seconds at 250 to 300 ° C. However, it can also be used for such applications.

Hereinafter, an antenna design method will be described.
The antenna design uses the resonance frequency determined by the shape of the antenna line, the thickness of the line, the length of the line, etc. as an index. By bringing this resonance frequency close to the operating frequency of the IC chip to be used, the antenna receives the power from the reader / writer and transmits it to the IC chip to operate the IC chip.

It is generally difficult to analytically derive the resonance frequency from the antenna drawing. In practice, a method is often employed in which an antenna is prototyped and experimentally measured. However, since the RFID tag of the present invention is small, it is impossible to accurately prototype the antenna manually. On the other hand, it takes time and cost to fabricate the antenna from etching mask fabrication to etching. End up. For this reason, in the present invention, antenna design is performed using an electromagnetic field simulator (simulator software product name: HFSS manufactured by Ansys Japan Co., Ltd.), which can reduce time and cost. The resonance frequency is obtained from the simulation result by inputting the shape and material of the antenna, the capacitance of the IC chip, and the like to the electromagnetic field simulator. Then, the resonance frequency f _{0 of the} electric circuit formed by including the antenna inductance L and the IC chip capacitance C obtained by the electromagnetic field simulator is at or near the operating frequency of the IC chip. Design the antenna. Note that the resonance frequency in this case is a frequency at which the imaginary part of the impedance of the electrical closed circuit when the IC chip is connected to both ends of the antenna becomes zero.

It is easy to understand the design principle by considering an electric closed circuit when an IC chip is connected to both ends of a coil antenna, and can be considered as a simple LC resonance circuit. FIG. 5 shows an electrical equivalent circuit of the coil antenna 20 of FIG. The resonance frequency f _{0 in} this case is expressed by the following equation using the inductance L of the coil 50 that is an equivalent circuit of the coil antenna and the capacitance C of the capacitor 60 that is an equivalent circuit of the IC chip 30.

Ｃは使用するＩＣチップ３０の選定によって変えられ、Ｌはコイルアンテナの形状（特にコイルアンテナの直径と巻数）によって調整することができ、その結果、目的の共振周波数ｆ_０を実現することができる。特にＬの調整は有効で、コイルアンテナの直径を大きくしたり、巻数を増やすことでＬが増加し、その結果ｆ_０は減少する。

C is changed by the selection of the IC chip 30 to be used, L is can be adjusted by the shape of the coil antenna (particularly the coil antenna diameter and number of turns), as a result, it is possible to realize a resonance frequency f ₀ of the object . Adjustment of L is particularly effective, and L is increased by increasing the diameter of the coil antenna or increasing the number of turns. As a result, f ₀ is decreased.

  The resonance frequency (operating frequency) of the RFID package (IC chip) is preferably in the range of 13.56 MHz to 2.45 GHz, which is particularly commercially useful in radio law. In the case of RFID near the operating frequency of 0.86 to 0.96 GHz in the UHF band (Ultra High Frequency Band), the wavelength of the radio wave is about 30 cm. On the other hand, the size of the IC chip for the UHF band is usually 0. Since it is 6 mm square or less, it is difficult to form an antenna on which the IC chip operates normally on the IC chip in the on-chip antenna system. In addition, even with an RFID tag having a size of about several mm square, an antenna using a conventional design method can only obtain a communication distance of about 1 mm. However, according to the RFID package of the present invention by the design method using the electromagnetic field simulator described above, the communication distance for operating the RFID package can be achieved even with a several mm square antenna without using a conventional several cm square antenna. There is an excellent feature that can be greatly expanded. Specifically, it is an RFID package formed in a substantially rectangular parallelepiped, and the length of all sides is 1/50 or less with respect to a wavelength of 30 cm in the UHF band. The RFID package has a height of 1.0 mm, an antenna is formed inside, and the communication distance is 10 mm or more.

  The RFID package used in the present invention can be used by being embedded in a resin molded product such as a screw or a crimp pin and attached to a mounting target. Further, it can be used for management etc. by being attached to a product or sample to be mounted like a label with a double-sided tape or the like, and can be easily removed when the product is sold. If it is placed inside or around the slit of a conductor such as a metal product or metal part, as will be described later, the conductor acts as an external antenna, so the communication distance can be greatly increased compared to the case of an RFID package alone. A simple RFID tag system can be configured. By combining an RFID tag system configured by mounting the RFID package of the present invention on a product or sample with a reader, even a small variety of products such as glasses, watches, medical samples, semiconductor packages, etc. An automatic recognition system having a long communication distance and good workability can be configured. In this case, since the RFID tag system of the present invention has a long communication distance, an automatic recognition system can be configured in combination with a general-purpose reader or the like. The RFID tag system in the present invention is a combination of an RFID tag such as an RFID package and a conductor having a slit, and functions as an RFID tag as a whole.

  Examples of embodiments of the RFID tag system of the present invention are shown in FIGS. The RFID tag system 85 of the present invention includes an IC chip 30, an antenna 20 connected to the IC chip 30 to form an electrical closed circuit, and a sealing material 10 for sealing the IC chip 30 and the antenna 30. An RFID package 80 having a vertical, horizontal, and height size of 1/50 or less compared to the operating wavelength of the IC chip 30, and a conductor 100 including a slit 110 for arranging the RFID package 80 in or around it. Have.

  6A and 6B are a plan view and a cross-sectional view of an example of an embodiment of the RFID tag system 85 of the present invention. The outer periphery of the RFID package 80 is formed on a conductor 100 that is not electrically connected to the antenna 20 or the IC chip 30 of the RFID package 80 and whose surface is covered with an insulating material (not shown). A slit 110 is arranged. The conductor includes a lump of metal, a metal plate, a metal part, a product, a part of these, and the like. In FIG. 6, the conductor 100 including the slit 110 serves as an external antenna, and a signal from a reader (not shown) is efficiently transmitted to the RFID package 80. As a result, the communication distance is improved.

  By receiving a signal from the reader, a current flows through the wall surface of the slit 110 provided in the conductor 100. The magnetic flux generated by the current generates a current in the coiled antenna of the RFID package, so that a voltage is applied to the IC chip to operate. This principle can be utilized because the antenna of the RFID package is coiled.

  Therefore, by arranging the RFID package inside or around the slit provided in the conductor, the magnetic flux generated in the slit 110 is transmitted to the coiled antenna of the RFID package, so that the efficiency is improved and the communication distance is increased. In particular, when the coiled antenna of the RFID package is disposed inside the slit provided in the conductor (within the thickness of the conductor), a large amount of magnetic flux generated in the slit 110 is transmitted to the coiled antenna, and thus more efficient. The communication distance is long. Further, when the coiled antenna of the RFID package is arranged so as to be substantially parallel to the conductor surface on which the slit is formed, the efficiency is further improved and the communication distance is increased. Here, the inside of the slit means the inside of the space formed by the slit, and the periphery of the slit means not only the inside of the slit but also the range from the inner wall of the slit to 2 mm. FIG. 6B shows a specific example when the RFID package 80 including the coiled antenna 20 is disposed inside the slit 110 provided in the conductor 100.

  For the same reason, if the slit is arranged at a position closer to the position than the position far from the coiled antenna of the RFID package, the communication distance becomes longer. It is desirable that the distance from the end of the coiled antenna of the RFID package to the wall surface of the slit is within 2 mm from the viewpoint of good efficiency in transmitting the magnetic flux generated by the slit to the coil antenna.

  The conductor includes a lump of metal, a metal plate, a metal part or product, or a part of a metal part or product. If the conductor is mainly composed of copper, aluminum, or iron, by providing a slit in the conductor, a magnetic flux is generated in the slit, and this magnetic flux is transmitted to the coiled antenna of the RFID package, so the efficiency is good. This is desirable because the communication distance becomes long. The insulating material that covers the surface of the conductor is not particularly limited as long as it insulates and protects the surface of the conductor, but an insulating paint or the like generally used as an insulating coating such as metal can be used.

  If the conductor having the slit is a metal part or product that can also be a target for mounting the RFID package, or a part of the metal part or product, the slit is bothered to configure the RFID tag system of the present invention. Since it is not necessary to prepare a conductor to be provided, the cost can be reduced. Even if the size of the RFID package itself, which is an RFID tag, is small, a long communication distance can be realized as compared with a single small RFID tag by the action of a conductor having a slit to be mounted. Further, since the RFID package is disposed inside or around the slit provided in the conductor, for example, the RFID package is embedded in a resin screw, a part of the slit is processed with a screw hole, and the screw is inserted into the slit. By attaching the screw to the part, it can be easily attached to a metal part or metal product which has been difficult to attach the RFID tag.

  The slit in the present invention refers to an elongated opening provided so as to penetrate a conductor. The slit of the conductor can be formed by any one of cutting, pressing, powder metallurgy, welding, and casting, for example. The inner wall of the slit may be exposed with the conductor or covered with an insulating material.

  7 (1) to 7 (3) show the shape of the slit 110 that is efficient as an external antenna when provided on the conductor 100. FIG. In (1), the slit 110 is linear. (2) is a U-shape. (3) is a meander line type.

The slit length is preferably 1/3 to 2/3 of the operating wavelength of the IC chip, and most preferably about 1/2 (half). When the operating frequency of the IC chip is f ₀ (Hz) and the speed of light is c (m / sec), the operating wavelength λ (m) of the IC chip can be expressed by the following equation.

例えば、動作周波数が９５０ＭＨｚの場合、動作波長は３１５．６ｍｍであり、スリットの長さはその半分の１５７．８ｍｍ程度が好適である。

For example, when the operating frequency is 950 MHz, the operating wavelength is 315.6 mm, and the length of the slit is preferably about 157.8 mm, which is half that length.

  8 (1) to 8 (3) show an RFID tag 85 in which one of the ends in the length direction of the slit 110 provided in the conductor 100 is an open end (open state). In (1), the slit 110 is linear. (2) is L-shaped. (3) is a meander line type. In this case, since one end of the slit 110 becomes an open end, a mirror effect is produced. Therefore, the length of the slit 110 is preferably 1/8 to 3/8 of the operating wavelength of the IC chip, and 1/4 (4 A fraction of 1) is most preferable.

  In FIG. 9, a slit 110 is provided in the metal part 120, the RFID package 80 is embedded in the resin screw 130, a screw hole is formed in a part of the slit 110, and the resin screw 130 is screwed in a part of the slit 110. By stopping, the RFID package 80 shows the RFID tag 85 arranged around the slit 110. In this example, a coiled antenna (not shown) of the RFID package 80 is disposed substantially parallel to the periphery of the slit 110 and above the surface of the metal component 120. Depending on the position embedded in the resin screw 130 of the RFID package 80, it can also be arranged inside the slit 110. The resin screw 130 may be a resin-made crimp pin, and the RFID package 80 can be easily arranged around the slit 110 by press-fitting the crimp pin into a part of the slit.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
Several methods for manufacturing RFID packages have been proposed. In the present invention, the method for manufacturing the RFID package is not particularly limited. This time, an example was implemented.
As a resin base material, a polyimide base material with a copper foil (MCF-5000I manufactured by Hitachi Chemical Co., Ltd., polyimide thickness 25 μm, copper foil thickness 18 μm) in which a copper foil was bonded to one side of a polyimide base material was prepared. By etching the copper foil of the polyimide substrate with copper foil, the coil antenna 20 as shown in FIG. 3 is within the range of 2.5 mm square, and the conductor wire width / interconductor wire width is 0.1 mm / 0.1 mm. , Formed with 4 turns. At the same time, a die pad (not shown) for mounting the IC chip 30 was formed.

  Next, an IC chip having a size of about 0.5 mm × 0.5 mm × 0.1 mm, a capacitance of 0.8 pF, and an operating frequency of about 0.86 to 0.96 GHz was used. This IC chip was mounted on a die pad using a die bonding material, and the antenna and the IC chip were directly connected by wire bonding. Next, the antenna, IC chip, and wire for wire bonding on one side of the substrate were sealed with a sealing material. Finally, dicing to a required size was performed to produce an RFID package.

The reading evaluation method and experimental results will be described below.
As a reader / writer, product name: UI-9061 (output 1 W) manufactured by LS Sangyo Co., Ltd. was used. The reading evaluation of the RFID tag system and the RFID package was performed in a state where there is no obstacle around 5 m around the reading unit of the reader / writer. The maximum distance from the reader / writer reader to the RFID tag system and the RFID package when the RFID tag system and the RFID package can be read by the reader / writer was measured.

(Comparative Example 1)
As a result of measuring the reading distance of the manufactured RFID package as it was with a reader, the reading distance was 18 mm.

Example 1
Using the manufactured RFID package, as shown in FIG. 7 (1), a slit 110 having a length of 150 mm and a width of 3 mm is formed linearly on an aluminum plate having a thickness of 5 mm, which is a conductor 100. An RFID tag system 85 is manufactured by placing the RFID package 80 in the slit 110 in the vicinity of 30 mm from the end of the slit (that is, in the vicinity of 30 mm on the left side from the right end of the slit 110 in FIG. 7A). As a result of measuring the reading distance, the reading distance was 3.5 m. Further, as shown in FIG. 7B, the shape of the slit 110 is made substantially U-shaped facing upward, and the RFID package 80 is disposed inside the slit 110 near 30 mm from the upper right end of the slit 110, As a result of measuring the reading distance, the reading distance was 3.2 m. Furthermore, as shown in FIG. 7 (3), the slit 110 has a substantially meander shape, and the reading distance is 3.0 m even if the RFID package is arranged in the slit 110 near 30 m from the right end of the slit 110. there were. In any case, a communication distance close to 150 to 200 times as compared with the case where the RFID package 80 is a single unit (Comparative Example 1) was realized.

(Example 2)
Next, using the manufactured RFID package 80, as shown in FIG. 8 (1), a slit 110 having a length of 75 mm, a width of 3 mm, and one of which is an open end is formed on a 5 mm thick aluminum plate as the conductor 100. The RFID package is formed inside the slit 110 formed in a straight line and in the vicinity of 30 mm from the end in the length direction (that is, in the vicinity of 30 mm on the left side from the right end of the slit 110 in FIG. 8A). As a result of manufacturing RFID tag 85 by arranging 80 and measuring the reading distance, the reading distance was 2.7 m. Further, as shown in FIG. 8 (2), the shape of the slit 110 is substantially L-shaped, and the RFID package 80 is disposed inside the slit 110 near 30 mm from the upper right end of the slit 110, and the reading distance is measured. As a result, the reading distance was 2.6 m. Furthermore, as shown in FIG. 8 (3), even when the slit 110 is substantially meandered and the RFID package is disposed in the slit 110 near 30 m from the right end of the slit 110, the reading distance is 2.5 m. Met. In both cases, a communication distance close to 150 times that of the case where the RFID package 80 is a single unit of about half the size of FIG. 7 (Comparative Example 1) was realized.

(Example 3)
Next, using the manufactured RFID package 80, the RFID package 80 is embedded in an M6 size (diameter 6 mm) resin screw 130 as shown in FIG. Then, a slit 110 having a length of 75 mm and a width of 3 mm was formed by cutting, M6 screw holes were formed in a part of the slit 110, and the resin screw 130 in which the RFID package 80 was embedded was screwed. The coiled antenna (not shown) of the RFID package 80 is disposed substantially parallel to the periphery of the slit 110 (within 2 mm from the inner wall of the slit 110) and above the surface of the metal component 120. As a result of measuring the reading distance, a reading distance of about 2 m was realized.

The RFID tag of the present invention includes products, packaging, cards, documents, glasses, watches (especially watches and other small items), semiconductors, medical applications (samples taken from patients, etc.), linens used in hotels, work clothes, etc. It can be used for weatherproof labels used outdoors, carts such as shopping carts, gas cylinders and other products for management, identification, information presentation, information recording, and anti-counterfeiting.

DESCRIPTION OF SYMBOLS 1 Base material 10 Sealing material 20 Antenna or coil antenna or coiled antenna 30 IC chip 40 Wire 50 of wire bonding Coil (antenna)
60 Capacitor (IC chip)
70 Port 80 to be input during simulation RFID package or RFID tag 85 RFID tag system 90 Die pad 100 Conductor 110 Slit 120 Metal part 130 Resin screw

Claims (14)

  An IC chip, an antenna connected to the IC chip to form an electrical closed circuit, and the IC chip and a sealing material for sealing the antenna, and the vertical and horizontal directions with respect to the operating wavelength of the IC chip. An RFID tag system comprising: an RFID package having a height size of 1/50 or less; and a conductor having a slit disposed inside or around the RFID package.   2. The RFID tag system according to claim 1, wherein the antenna of the RFID package is a single layer coil.   3. The RFID tag system according to claim 1, wherein the conductor is mainly composed of copper, aluminum, or iron.   4. The RFID tag system according to claim 1, wherein the conductor is a metal part or a metal product to which the RFID package is attached or a part of the metal part or the metal product.   5. The RFID tag system according to claim 1, wherein the conductor slit is formed by any one of cutting, pressing, powder metallurgy, welding, and casting.   6. The RFID tag system according to claim 1, wherein a surface of the conductor is covered with an insulating material.   7. The RFID tag system according to claim 1, wherein the shape of the slit provided in the conductor is substantially linear, substantially U-shaped, or substantially meander-lined.   8. The RFID tag system according to claim 1, wherein the length of the slit is approximately ½ of the operating wavelength of the IC chip.   8. The RFID tag system according to claim 1, wherein one of both ends of the slit is an open end, and the length of the slit is approximately 1/4 of the operating wavelength of the IC chip.   10. The RFID tag system according to claim 1, wherein the operating frequency of the IC chip is between 0.86 and 0.96 GHz.   11. The RFID package according to claim 1, wherein the RFID package is embedded in a resin screw, a screw hole is formed in a part of a slit provided in the conductor, and the screw is screwed to a part of the slit. Accordingly, the RFID tag system in which the RFID package is disposed inside or around the slit.   11. The RFID package according to claim 1, wherein the RFID package is embedded in a resin-made crimp pin, and the RFID package is disposed inside or around the slit by press-fitting the crimp pin into a part of the slit. RFID tag system.   13. The RFID tag system according to claim 1, wherein the size of the RFID package is 2.5 mm or less × 2.5 mm or less × 1.0 mm or less in height.   14. An RFID package for use in the RFID tag system according to claim 1, wherein an IC chip, an antenna connected to the IC chip to form an electrically closed circuit, and the IC chip and the antenna are sealed. An RFID package having a sealing material and having a vertical, horizontal, and height size of 1/50 or less with respect to an operating wavelength of the IC chip.

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