JP2012137894A - Radio ic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio IC device in which possibility of being damaged by concentration of stress on a radio IC element when attached to a curved surface is removed.SOLUTION: A radio IC device includes: a dielectric body 20 with flexibility; a radiator 30 provided to at least one main surface of the dielectric body 20, made from a metal material, and with flexibility; and a radio IC element 50 coupled to the radiator 30. By bending or curving a part of the radiator 30, a gap portion 28 is formed between the dielectric body 20 and the radiator 30, and the radio IC element 50 is disposed in the gap portion 28.

Description

  The present invention relates to a wireless IC device, and more particularly to a wireless IC device used in an RFID (Radio Frequency Identification) system.

  In recent years, as an article information management system, a reader / writer that generates an induced magnetic field and an RFID tag (also referred to as a wireless IC device) attached to the article are communicated in a non-contact manner using an electromagnetic field, and predetermined information is transmitted. An RFID system for transmission has been put into practical use. This RFID tag includes a wireless IC chip that stores predetermined information and processes predetermined wireless signals, and an antenna (radiator) that transmits and receives high-frequency signals, and includes various articles to be managed (or packaging thereof). Used by sticking to material).

  As this type of RFID tag, Patent Documents 1 and 2 describe a metal-compatible tag that operates even when attached to the surface of a metal article. This metal-compatible tag is obtained by winding a metal pattern serving as an antenna around a rectangular parallelepiped dielectric element. By the way, the surface of an article to which this type of RFID tag is attached has various shapes. For example, it is required to be able to be attached to a curved surface such as the surface of a gas cylinder. In the metal-compatible tag, if a flexible material such as silicon rubber is used as the dielectric element body and a flexible material such as metal foil is used as the radiator, the curved surface can be obtained. It becomes possible to stick. However, the dielectric element body needs to have a certain thickness, and even if the element body itself is flexible, when the element body is bent, stress is concentrated on the wireless IC chip, and the wireless IC The chip may be damaged.

JP 2006-053833 A JP 2007-272264 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wireless IC device that eliminates the risk of stress concentration on the wireless IC element and damage even when the dielectric body is bent on a curved surface. is there.

The wireless IC device according to the first aspect of the present invention is:
A dielectric body having flexibility;
A flexible radiator made of a metal material provided on at least one main surface of the dielectric body;
A wireless IC element coupled to the radiator;
With
Forming a gap between the dielectric body and the radiator by bending or bending a portion of the radiator;
The wireless IC element is disposed in the gap,
It is characterized by.

  The wireless IC device according to the second aspect of the present invention is characterized in that the dielectric element body is bonded to the surface of a metal body.

  In the wireless IC device, even if the wireless IC device is attached to the surface of a curved article (metal body) and the dielectric element body is forcibly bent and stress is generated, the wireless IC element is a dielectric substance. Since it is disposed in the gap formed between the element body and the radiator, stress acting on the wireless IC element is relieved, and there is no possibility of damaging the wireless IC element, thereby improving the reliability.

  According to the present invention, even when it is attached to a curved surface, it is possible to eliminate the risk of stress concentration on the wireless IC element and damage, thereby improving reliability.

The wireless IC device which is 1st Example is shown, (A) is an external appearance perspective view, (B) is sectional drawing, (C) is a top view. It is sectional drawing which shows the state which affixed the said wireless IC device on the curved surface of the metal body. It is sectional drawing which shows the radio | wireless IC device which is 2nd Example. It is sectional drawing which shows the radio | wireless IC device which is 3rd Example. The radio | wireless IC device which is 4th Example is shown, (A) is an external appearance perspective view, (B) is sectional drawing. It is a perspective view which shows the radio | wireless IC chip as a radio | wireless IC element. It is a perspective view which shows the state which mounted the said radio | wireless IC chip on the electric power feeding circuit board as a radio | wireless IC element. It is an equivalent circuit diagram showing an example of a power feeding circuit. It is a top view which shows the laminated structure of the said feeder circuit board.

  Embodiments of a wireless IC device according to the present invention will be described below with reference to the accompanying drawings. In each figure, common parts and portions are denoted by the same reference numerals, and redundant description is omitted.

(Refer to the first embodiment, FIGS. 1 and 2)
A wireless IC device 1A according to the first embodiment is used for UHF band communication. As shown in FIG. 1, a dielectric element body 20 having a rectangular parallelepiped shape, a radiator 30 made of a metal pattern, The wireless IC element 50 is used.

  The dielectric body 20 is made of a dielectric material (insulating or magnetic material) such as a fluorine-based resin material or a urethane-based resin material, and has flexibility. The dielectric body 20 itself is formed of a flexible material. However, since the slit (not shown) extending in the short side direction is formed on the surface, the dielectric body 20 is more flexible. You may have sex.

  The radiator 30 is made of a metal material such as copper foil or aluminum foil having flexibility, and is provided from the upper surface (one main surface) of the dielectric element body 20 to the lower surface (the other main surface) through both end surfaces. . The radiator 30 is provided on a flexible resin film 35 (which may be a double-sided tape). The film 35 is attached to the surface of the dielectric body 20 with the radiator 30 and the wireless IC element 50 inside.

  When the radiator 30 and the resin film 35 are attached to the surface of the dielectric element body 20, the radiator 30 and the resin film 35 are bent at the portions indicated by a and b extending in the short side direction. A space 28 having a triangular shape in cross section is formed between the body 30 and the body 30. A gap 29 is also formed between both ends of the radiator 30 and both ends of the dielectric body 20. In this embodiment, the film 35 is attached to the upper and lower surfaces of the dielectric element body 20 with the radiator 30 and the wireless IC element 50 inside. However, the film 35 may be attached to only one of the upper surface and the lower surface of the dielectric body 20.

  The radiator 30 is divided into power supply portions 30 a and 30 b facing the short side direction of the dielectric element body 20 in the gap portion 28, and is separated by a gap 31 on the lower surface of the dielectric element body 20. Yes. The wireless IC element 50 is mounted on the power feeding units 30a and 30b. The wireless IC element 50 processes an RF signal, and details thereof will be described below with reference to FIGS. The coupling between the wireless IC element 50 and the power feeding units 30a and 30b is an electromagnetic coupling or a direct electrical coupling (DC connection) such as a solder bump.

  Incidentally, in the first embodiment, the wireless IC element 50 is disposed in the gap portion 28. That is, the power feeding units 30a and 30b are arranged on an inclined surface lifted from one main surface of the dielectric element body 20, and the wireless IC element 50 is coupled to the power feeding units 30a and 30b. The gap 28 is symmetrical to the left and right of FIG. The wireless IC element 50 is arranged at a position slightly offset from the center position a along the long side direction of the dielectric element body 20.

  By the way, if the wireless IC device 1A is attached to the flat portion of the article, there is no problem. However, as shown in FIG. 2, the wireless IC device 1A may be attached to the curved portion of the metal body 70 such as a gas cylinder. is there. As described above, when the lower surface of the wireless IC device 1A is attached to a curved surface, the wireless IC device 1A is curved along the long side direction because the dielectric body 20 and the radiator 30 have flexibility.

  When the bending occurs, a bending stress indicated by an arrow c is generated in the dielectric element body 20 and the radiator 30 having relatively rigidity, and the wireless IC element 50 is assumed to be in the dielectric element body without the gap portion 28 being present. If it is in close contact with 20, stress concentrates on the wireless IC element 50 and the wireless IC element 50 may be damaged. However, in the first embodiment, since the wireless IC element 50 is disposed in the gap portion 28, the gap portion 28 is slightly crushed by the curvature of the dielectric element body 20. Thus, the risk of damaging the wireless IC element 50 is eliminated. In addition, the voids 29 formed at both ends of the dielectric element body 20 promote the bending of the dielectric element body 20 and relieve the stress generated in the wireless IC element 50.

  In particular, in the first embodiment, the wireless IC element 50 is disposed at a position slightly offset along the long side direction of the dielectric element body 20 from the center position a. Stress concentration can be effectively reduced. A radiator 30 made of a metal pattern is bonded onto a flexible resin film 35, and the resin film 35 is attached to the surface of the dielectric element body 20 with the radiator 30 and the wireless IC element 50 inside. Therefore, the radiator 30 and the wireless IC element 50 are protected from the outside by the resin film 35. Furthermore, since the dielectric element body 20 is attached so as to be wound with the resin film 35, the wireless IC device 1A can be manufactured easily and efficiently.

  Further, as shown in FIG. 1C, when the wireless IC element 50 has a rectangular parallelepiped shape having a long side and a short side in plan view, the short side of the wireless IC element 50 is the dielectric element body 20. When coupled to the radiator 30 so as to coincide with the long side direction, the stress acting on the wireless IC element 50 when the dielectric element body 20 is bent can be further relaxed.

  Here, the communication operation of the wireless IC device 1A will be schematically described. A predetermined high-frequency signal is transmitted from the wireless IC element 50 to the upper surface portion of the radiator 30 via the power feeding units 30a and 30b, and a potential difference from the lower surface portion. Thus, the upper surface portion operates as a patch antenna. Thus, the characteristics (for example, wideband frequency characteristics) of the signals supplied from the power feeding units 30a and 30b can be transmitted from the radiator 30 to the outside as they are. Similarly, when the radiator 30 receives a high frequency signal from the outside, power is supplied to the wireless IC element 50 from the power feeding units 30a and 30b.

  The electromagnetic field radiation from the radiator 30 alone is weak and can be communicated only over a short distance. When the wireless IC device 1A is attached to the metal body 70, the lower surface portion of the radiator 30 is capacitively coupled to the metal body 70, and a strong electromagnetic field is radiated from the metal body 70 toward the surface thereof. Communication with is possible. Note that the capacity formed between the radiator 30 and the metal body 70 may be infinite. In other words, the lower surface portion of the radiator 30 may be directly electrically connected to the metal body 70.

(Refer to the second embodiment, FIG. 3)
As shown in FIG. 3, the wireless IC device 1 </ b> B according to the second embodiment forms a recess 21 larger than the wireless IC element 50 at a position on the upper surface of the dielectric body 20 and facing the wireless IC element 50. It is a thing. When the dielectric body 20 is curved as shown in FIG. 2, the wireless IC element 50 enters the recess 21 and the stress concentration is further relaxed. Therefore, the gap 29 (see FIG. 1B) does not necessarily have to be formed at both ends of the dielectric body 20.

  The other configurations of the second embodiment are the same as those of the first embodiment, and the operation and effects thereof are as described in the first embodiment.

(Refer to the third embodiment, FIG. 4)
As shown in FIG. 4, the wireless IC device 1 </ b> C according to the third embodiment is arranged such that the gap 31 of the radiator 30 does not overlap the wireless IC element 50 in plan view. Thus, since the wireless IC element 50 is covered with the lower surface portion of the radiator 30, a shielding effect is generated. Other configurations of the third embodiment are the same as those of the first embodiment, and the operation and effects thereof are as described in the first embodiment.

(Refer to the fourth embodiment, FIG. 5)
As shown in FIG. 5, the wireless IC device 1D according to the fourth embodiment is one in which the wireless IC device main body is accommodated in a protective case 40 having flexibility. The protective case 40 includes a flat base portion 41 made of an elastomer resin and the like and a box-shaped portion 42. After the wireless IC device main body is accommodated, a flange portion 43 formed around the box-shaped portion 42 is used as a base portion. It is sealed by heat welding to 41. In the wireless IC device 1D, the wireless IC device 1D is attached to the surface of the article by the adhesive layer 45 provided on the lower surface of the base portion 41.

  When this type of wireless IC device is affixed to a gas cylinder or the like, an impact is applied in various situations such as contact between gas cylinders, loading on a truck, and contact with a loading platform when carrying out. As in the fourth embodiment, protection by the case 40 improves environmental resistance and impact resistance. A gap 44 having at least the height of the gap 28 is provided between the top surface 42a of the case 40 and the upper surface of the dielectric element body 20 (including the resin film 35 and the radiator 30). Is preferred.

(Wireless IC element, see FIGS. 6 to 9)
The wireless IC element 50 will be described below. The wireless IC element 50 may be a wireless IC chip 51 that processes a high frequency signal as shown in FIG. 6, or a resonant circuit having a predetermined resonance frequency with the wireless IC chip 51 as shown in FIG. It may be comprised with the electric power feeding circuit board 65 containing.

  The wireless IC chip 51 shown in FIG. 6 is configured as a silicon semiconductor integrated circuit chip and includes a clock circuit, a logic circuit, a memory circuit, and the like, and necessary information is stored in the memory. The wireless IC chip 51 is provided with input / output terminal electrodes 52 and 52 and mounting terminal electrodes 53 and 53 on the back surface thereof. The input / output terminal electrodes 52 and 52 are electrically connected to the power supply portions 30a and 30b shown in the above embodiments via metal bumps or the like. In addition, Au, solder, etc. can be used as a material of a metal bump.

  As shown in FIG. 7, when the wireless IC chip 51 and the power supply circuit board 65 constitute the wireless IC element 50, various power supply circuits (including resonance circuits / matching circuits) may be provided on the power supply circuit board 65. it can. For example, as shown in FIG. 8 as an equivalent circuit, the feeder circuit 66 includes inductance elements L1 and L2 having inductance values different from each other and magnetically coupled in opposite phases to each other (indicated by a mutual inductance M). May be. The power feeding circuit 66 has a predetermined resonance frequency, and aims at impedance matching between the impedance of the wireless IC chip 51 and the radiator 30. Note that the wireless IC chip 51 and the power feeding circuit 66 may be electrically connected (DC connection) or may be coupled via an electromagnetic field.

  The power feeding circuit 66 transmits a high frequency signal having a predetermined frequency transmitted from the wireless IC chip 51 to the antenna, and supplies the received high frequency signal to the wireless IC chip 51 through the antenna. Since the power feeding circuit 66 has a predetermined resonance frequency, impedance matching can be easily achieved, and the electrical length of the matching circuit portion of the radiator 30 can be shortened.

  Next, the configuration of the feeder circuit board 65 will be described. As shown in FIGS. 6 and 7, the input / output terminal electrode 52 of the wireless IC chip 51 is provided on the power supply terminal electrodes 142a and 142b formed on the power supply circuit board 65, and the mounting terminal electrode 53 is provided on the mounting terminal electrode 143a. , 143b through metal bumps or the like.

  As shown in FIG. 9, the feeder circuit board 65 is obtained by laminating, pressing and firing ceramic sheets 141a to 141h made of a dielectric or magnetic substance. However, the insulating layer constituting the power supply circuit board 65 is not limited to the ceramic sheet, and may be a thermosetting resin such as a liquid crystal polymer or a resin sheet such as a thermoplastic resin. On the uppermost sheet 141a, power supply terminal electrodes 142a and 142b, mounting terminal electrodes 143a and 143b, and via-hole conductors 144a, 144b, 145a, and 145b are formed. The via-hole conductors 144a and 145a are connected by a power supply terminal electrode 142a. The via-hole conductors 144b and 145b are connected by a power supply terminal electrode 142b. On the second to eighth sheets 141b to 141h, wiring electrodes 146a and 146b constituting the inductance elements L1 and L2 are formed, and via-hole conductors 147a, 147b, 148a and 148b are formed as necessary. ing.

  By laminating the above sheets 141a to 141h, the inductance element L1 in which the wiring electrode 146a is spirally connected by the via hole conductor 147a is formed, and the inductance in which the wiring electrode 146b is spirally connected by the via hole conductor 147b. Element L2 is formed. In addition, a capacitance is formed between the wiring electrodes 146a and 146b.

  The end 146a-1 of the wiring electrode 146a on the sheet 141b is connected to the power supply terminal electrode 142a via the via hole conductor 145a, and the end 146a-2 of the wiring electrode 146a on the sheet 141h is connected via the via hole conductors 148a and 145b. Connected to the power supply terminal electrode 142b. The end 146b-1 of the wiring electrode 146b on the sheet 141b is connected to the power supply terminal electrode 142b via the via-hole conductor 144b, and the end 146b-2 of the wiring electrode 146b on the sheet 141h is connected via the via-hole conductors 148b and 144a. Connected to the power supply terminal electrode 142a.

  In the above power feeding circuit 66, the inductance elements L1 and L2 are wound in opposite directions, so that the magnetic fields generated by the inductance elements L1 and L2 are canceled. Since the magnetic field is canceled out, it is necessary to lengthen the wiring electrodes 146a and 146b to some extent in order to obtain a desired inductance value. As a result, the Q value is lowered, so that the steepness of the resonance characteristics is lost, and the bandwidth is increased in the vicinity of the resonance frequency.

  The inductance elements L1 and L2 are formed at different positions on the left and right when the feeder circuit board 65 is viewed in plan. The magnetic fields generated by the inductance elements L1 and L2 are opposite to each other. Thus, when the feeding circuit 66 is coupled to the antenna, a reverse current is excited in the antenna, and a current can be generated in the adjacent metal plate, and the metal plate is radiated by the potential difference due to the current. It can be operated as an (antenna).

  By incorporating the resonance / matching circuit in the power supply circuit board 65, characteristic fluctuations due to the influence of external articles can be suppressed, and deterioration in communication quality can be prevented. Further, if the wireless IC chip 51 constituting the wireless IC element 50 is arranged toward the center in the thickness direction of the power supply circuit board 65, the wireless IC chip 51 can be prevented from being broken, and the machine as the wireless IC element 50 can be prevented. Strength can be improved.

(Other examples)
The wireless IC device according to the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist thereof.

  In particular, the dielectric body does not necessarily have a rectangular parallelepiped shape, and the material may be a thermosetting resin such as rubber, elastomer, epoxy, or a thermoplastic resin such as polyimide, or on the surface. As long as it has the necessary flexibility by forming the recess, it may be a ceramic such as LTCC or may be formed in multiple layers.

  In each of the above embodiments, the radiator is shown as being provided on the resin film. However, the radiator is bonded to the dielectric element body entirely or partially using a double-sided tape or the like. It may be. Furthermore, although the gap portion is formed by bending the radiator and the resin film, the gap portion may be formed by bending the radiator and the resin film outward.

  Further, propagation of RF signals in the radiator and delivery of signals between the radiator and the wireless IC element are not limited to the modes described in the above embodiments, and various propagation modes and delivery modes can be adopted. The shape and size are also arbitrary.

  As described above, the present invention is useful for a wireless IC device, and is particularly excellent in that it eliminates the possibility of stress being concentrated on the wireless IC element when it is attached to a curved surface.

DESCRIPTION OF SYMBOLS 1A-1D ... Wireless IC device 20 ... Dielectric body 28 ... Air gap part 30 ... Radiator 35 ... Resin film 40 ... Protective case 50 ... Wireless IC element 65 ... Power feeding circuit board 70 ... Metal body

Claims (10)

A dielectric body having flexibility;
A flexible radiator made of a metal material provided on at least one main surface of the dielectric body;
A wireless IC element coupled to the radiator;
With
Forming a gap between the dielectric body and the radiator by bending or bending a portion of the radiator;
The wireless IC element is disposed in the gap,
A wireless IC device characterized by the above.   2. The wireless IC device according to claim 1, wherein the wireless IC element is disposed at a position offset from a bending position of the gap portion or a center position of the curved portion. The dielectric element body has a rectangular parallelepiped shape having a long side and a short side in plan view,
The wireless IC element is disposed at a position offset along the long side direction of the dielectric body;
The wireless IC device according to claim 1, wherein the wireless IC device is a wireless IC device. The dielectric element body has a rectangular parallelepiped shape having a long side and a short side in plan view,
The wireless IC element has a rectangular parallelepiped shape having a long side and a short side in plan view, and the short side is aligned with the long side direction of the dielectric element body and is coupled to the radiator.
The wireless IC device according to any one of claims 1 to 3, wherein: The radiator is provided on a flexible film;
The film is attached to the surface of the dielectric body with the radiator and the wireless IC element inside.
The wireless IC device according to any one of claims 1 to 4, wherein:   The radiator is disposed continuously from one main surface of the dielectric element body through both end surfaces to the other main surface, and bonded to the one main surface and / or the other main surface. 6. The wireless IC device according to claim 1, wherein the wireless IC device is characterized in that:   The wireless IC device according to any one of claims 1 to 6, wherein the wireless IC element is a wireless IC chip that processes a predetermined wireless signal.   7. The wireless IC element according to claim 1, wherein the wireless IC element includes a wireless IC chip that processes a predetermined wireless signal and a power supply circuit board including a power supply circuit having a predetermined resonance frequency. The wireless IC device according to 1.   9. The wireless IC device according to claim 1, wherein the dielectric element body, the radiator, and the wireless IC element are accommodated in a protective case having flexibility. . A dielectric body having flexibility;
A flexible radiator made of a metal material provided on at least one main surface of the dielectric body;
A wireless IC element coupled to the radiator;
With
Forming a gap between the dielectric body and the radiator by bending or bending a portion of the radiator;
The wireless IC element is disposed in the gap,
The dielectric element is attached to the surface of a metal body;
A wireless IC device characterized by the above.

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