KR20060119635A - Rfid tag - Google Patents

Abstract

An RFID(Radio Frequency IDentification) tag is provided to absorb external force such as external tensile and bending force, and offer an antenna having a structure generating no crack while realizing an excellent RF performance. The antenna(110) is connected to an RFID chip(150). A molding part(160) seals the RFID chip and a part of the antenna connected to the RFID chip. A stress buffering member(120) is combined with the antenna close to the molding part and has flexibility to buffer external stress. The antenna is equipped with a connector(111) partially buried to the molding part and a main antenna(112) arranged to the outside of the molding part. The stress buffering material connecting the connector and the main antenna is made of a conductive material, such as a spring, having elasticity.

Description

RFID tag {RFID tag}

1 is a plan view showing a conventional RFID tag from above.

FIG. 2 is a side view of the RFID tag shown in FIG. 1.

3 is a plan view according to a preferred embodiment of the present invention.

4 is a plan view illustrating a modification of FIG. 3.

5 is an exploded perspective view illustrating the stress relaxation member of FIG. 4 in an enlarged manner.

Explanation of symbols on the main parts of the drawings

100: RFID tag 110: antenna

111: connecting portion 112: main antenna portion

120: stress relief member 150: RFID chip

160: molding part 221: conductive member

225: engagement member

The present invention relates to an RFID tag (Radio Frequency IDentification tag), and more particularly, to an RFID tag of an improved structure in which damage or inability to recognize an RFID tag is prevented even in an operating environment in which an external force is applied.

In recent years, wireless communication technology has been widely used in all industrial fields including distribution, and examples of wireless communication technology include technology fields such as smart cards and radio frequency identification (RFID).

Such wireless communication technology may be used to obtain information about a product wirelessly. For this purpose, the wireless communication system includes a transponder attached to the product and a reader in wireless communication with the transponder. The transponder is equipped with an antenna and an RFID chip so that information from the reader is stored and updated in the RFID chip through the antenna, and information stored in the RFID chip is transmitted to the reader through the antenna.

Among the products to which the wireless communication technology can be applied, for example, in the case of a tire, if the operating environment such as pressure or temperature applied to the tire is not properly controlled, the tire may be damaged during the manufacturing process of the tire or during operation of the vehicle. There is a risk of vehicle accidents, it is necessary to monitor the tire operating environment from time to time.

1 shows a prior art RFID tag, and FIG. 2 shows a side view of the RFID tag shown in FIG. 1. For convenience of description, Figure 1 shows the RFID tag before the protective paper and the release paper is attached. The RFID tag illustrated in the drawings includes a thin film 11, an antenna 10 formed on the thin film 11, and an RFID chip 50 electrically connected to the antenna 10. The thin film 11 may be formed of a polymer material such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), or the like. The antenna 10 may be formed by stacking and etching a copper foil layer or a thin aluminum layer on the thin film 11.

As shown in FIG. 2, an RFID chip 50 may be flip-chip bonded to an end of the antenna 10. More specifically, the anisotropic conductive adhesive 20 is interposed between the RFID chip 50 and the antenna 10 so that both 50 and 10 can be electrically connected. The RFID chip 50 and the antenna 10 are embedded by a molding part, and the protective paper 15 and the release paper 13 are disposed above and below the antenna 10, respectively. Each of the protective paper 15 and the release paper 13 is bonded by the adhesive layers 12 and 14. After removing the release paper 13, the RFID tag is mounted on a product for which information is to be obtained.

However, when the conventional RFID tag is mounted on a product such as a tire operating in a high pressure and high temperature environment, the antenna is deformed by the tension, compression force or bending load acting on the RFID tag, and the operating frequency is changed, or the RFID chip or RFID The connection between the chip and the antenna is damaged, which causes the reader to not recognize the RFID tag.

In order to prevent this, as described in US Patent No. 6630910, the antenna may be in the form of a wave, so that the antenna may increase or decrease to correspond to external tensile force. Such a wave antenna has a higher stress on the external tensile force than a general straight antenna, but there is a limit to the stress that can withstand the external tensile force due to the internal stress remaining in the antenna itself, and a certain stress or more at the bending portion of the antenna There is a problem that cracks occur when the force is applied.

SUMMARY OF THE INVENTION The present invention has been made to solve various problems including the above problems, and an object of the present invention is to provide an RFID tag having a structure capable of absorbing external tensile and bending forces.

It is still another object of the present invention to provide an RFID tag having an antenna having an excellent RF performance and a structure in which no crack occurs.

According to an embodiment of the present invention, an RFID tag includes: a molding part for sealing an RFID chip, an antenna connected to the RFID chip, and a portion of the RFID chip and an antenna connected to the RFID chip; It is coupled to an adjacent antenna and has a stress relief member that is flexible to relieve external stress.

In this case, the antenna includes a connection portion at least partially embedded in the molding portion, and a main antenna portion disposed outside the molding portion, and the stress relaxation member is elastically connected by connecting the connection portion and the main antenna portion. It is preferable that it is made of an electrically conductive material having.

The stress relief member may be a buffer spring.

On the other hand, the stress relaxation member: a coupling member for coupling the conductive members so as to be relatively movable between the plurality of conductive members and the adjacent conductive members disposed in a zigzag form, the conductive portion and cross each other It may be provided.

It is preferable to further include a coating member for embedding the molding part and the antenna, wherein the stress relaxation member is embedded in the coating member.

Hereinafter, with reference to an embodiment shown in the accompanying drawings the present invention will be described in more detail. 3 is a side view illustrating an RFID tag according to a preferred embodiment of the present invention.

Referring to FIG. 3, the RFID tag 100 according to the present embodiment includes an antenna 110, an RFID chip 150, a molding unit 160, and a stress relaxation member 120. The antenna 110 functions to receive or transmit a predetermined operating frequency. The antenna 110 may be formed of, for example, a two-pole wave antenna. The antenna 110 may be formed of leads of a lead frame used in a semiconductor manufacturing process.

The RFID chip 150 is bonded to the antenna 110, so that the antenna 110 and the RFID chip 150 are electrically connected to each other. One example of bonding bonding may be electrically connected by wire bonding. That is, although not shown in the drawing, the pad formed on the RFID chip 150 and the silver (Ag) plating layers formed on both ends of the antenna 110 may be connected to each other through the conductive wire. Alternatively, the antenna and the RFID chip may be connected by anisotropic conductive materials, and other methods may be used.

The molding part 160 is formed to surround the RFID chip 150 and a part of the antenna. The molding part 160 may be formed of a relatively hard material, so that the molding part 160 is not easily deformed by external force at the connection part where the RFID chip 150 and the antenna 110 are connected. That is, when the connection portion between the RFID chip 150 and the antenna 110 is easily deformed by an external force, a poor connection may occur between the antenna 110 and the RFID chip 150. As a hard molding material which forms this molding part 160, an epoxy compound is mentioned, for example.

The stress relief member 120 is coupled to the antenna 110 and has flexibility to relieve external stress. That is, the stress relaxation member 120 absorbs or disperses the impact force from the external impact, thereby alleviating stress concentration in the antenna 110. That is, for example, when the RFID tag 100 is mounted on a tire, considerable pressure is applied to the tire while the vehicle is in operation, and the tire is rapidly stretched and compressed at a stage before the final shape is formed in the tire manufacturing process. . The stress relief member 120 provides cushioning so that the inside of the RFID tag 100 is safely protected even when the tire is stretched and compressed.

In this case, the stress relief member 120 is coupled to the antenna at a position adjacent to the molding part 160. When encapsulating an RFID chip with the molding material, the stress concentration is concentrated at the antenna adjacent to the molding part 160. This is because the internal stress is left at the portion, and cracks can easily occur when an external tensile force is generated later, so as to prevent this.

The antenna 110 may include a connecting portion 111 and a main antenna portion 112. The connection part 111 is formed so that at least one part is embedded in the molding part 160, and the main antenna part 112 is disposed outside the molding part 160, and is responsible for transmitting and receiving a predetermined frequency signal. do.

The stress relaxation member 120 is preferably a conductive object having elasticity by connecting the connection portion 111 and the main antenna portion 112. That is, when the stress is concentrated in close proximity to the molding unit 160 and the conductive material having elasticity is coupled to a position where cracks are likely to occur, when the impact such as external tensile force occurs, the stress relaxation member 120 is The external shock can be absorbed while being stretched or compressed according to the impact.

Therefore, the main antenna unit 112 may have a high hardness, thereby maintaining high RF performance, and when the tensile force and the bending force are generated, the flexible stress relief member 120 may absorb the stress.

In this case, as shown in Figure 3, the stress relief member 120, as a buffer spring, may be formed to connect between the connecting portion 111 and the main antenna portion 112. The shock absorbing spring is formed of a conductive material such as copper, aluminum, steel, and the like against the tensile force to connect between the connecting portion 111 and the main antenna portion 112, and may also function as an antenna. . In particular, when the RFID tag 100 is mounted on a tire, an external bending force is frequently generated due to the rotation of the tire. When such an external force occurs, the shock can be smoothly cushioned due to the flexibility of the buffer spring. .

The shock absorbing spring may be welded to a contact portion of the main antenna 112 and the connection 111. Due to this. The cushioning springs are flowable to provide a structure that is resistant to tensile forces without leaving internal stresses on the antenna.

In addition, in order to protect the structure connecting the RFID chip 150 including the transmission and reception module and the antenna 110, a coating member 170 which is a conventional liquid coating material may be further provided. In this case, the stress relaxation member 120 is preferably embedded in the coating member 170, because the stress relaxation member 120 can also be protected by the coating member 170.

On the other hand, as shown in FIG. 4, the stress relaxation member 120 may include a plurality of conductive members 221 and a coupling member 225. In this case, the plurality of conductive members 221 are conductive and are arranged in a zigzag form with a portion crossing each other, and the coupling member 225 moves the conductive members 221 so that the adjacent conductive members can move relative to each other. Combine.

In this case, as shown in FIG. 5, the conductive members 221 are formed of the same material as the antenna 110, and a hole 223 is formed at one end thereof, and the coupling member 225 has the holes 223 of the conductive members. It may be a mechanical coupling means such as rivets, bosses fitted to. As a result, neighboring conductive members 221 may move relative to the coupling member 225. This structure makes the conductive member and the coupling member flexible, so that the force can be relaxed when an external tensile force is generated.

According to the present invention having the structure as described above, the stress is easily absorbed in the region where the stress is concentrated in the RFID tag, that is, the connection portion between the antenna and the RFID chip, so that a crack occurs at the connection portion between the antenna and the RFID chip. You will not.

In addition, the antenna may have a high RF performance by having a high hardness, while at the same time the stress relief member is flexible, so that the stress on the bending force and the tension of the tire can be smoothly absorbed.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and any person skilled in the art to which the present invention pertains may have various modifications and equivalent other embodiments. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (5)

RFID chip An antenna connected to the RFID chip A molding part for sealing the RFID chip and a part of an antenna connected to the RFID chip; An RFID tag coupled to the antenna adjacent to the molding part, the RFID tag having a stress relaxation member having flexibility to relieve external stress. The method of claim 1, The antenna is: A connection part at least partially embedded in the molding part; A main antenna unit disposed outside the molding unit, The stress relief member is an RFID tag, characterized in that made of a conductive object having elasticity by connecting between the connecting portion and the main antenna unit. The method of claim 2, The stress relief member is an RFID tag, characterized in that the buffer spring. The method of claim 1, The stress relief member is: A plurality of conductive members which are conductive and are arranged in a zigzag form with a portion intersecting with each other; and An RFID tag having a coupling member for coupling the conductive members to allow relative movement of the adjacent conductive members The method according to any one of claims 1 to 4, Further comprising a coating member for embedding the molding portion and the antenna, The stress relief member, RFID tag, characterized in that embedded in the coating member.

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