JP5896594B2 - Wireless IC device - Google Patents

Description

The present invention relates to a wireless IC device, particularly relates to a wireless IC device used for 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 Document 1 describes a loop antenna formed on an insulating film, a wireless IC chip mounted on the loop antenna, and then the insulating film wrapped around a dielectric member. Yes.

  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 RFID tag described in Patent Literature 1, if a material such as silicon is used as the dielectric member, it can be attached even on a curved surface. However, if only the flexibility of the material is used to adhere to the curved surface, when the dielectric member bends, stress concentrates between the dielectric member and the loop antenna, and the loop antenna becomes a dielectric. There is a risk of peeling from the member or cracking of the dielectric member. Alternatively, the loop antenna may be distorted, the communication characteristics may fluctuate, and the communication reliability may decrease.

JP 2007-272264 A

An object of the present invention, even when attached to a curved surface without peeling the element body and the radiator occurs, and is that the communication characteristics to provide a hard wireless IC device varies.

The wireless IC device according to the first aspect of the present invention is:
A wireless IC device attached to a curved surface of a metal body,
A dielectric element body having an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface;
A metal pattern that functions as a radiator,
A flexible film for sticking and holding the metal pattern;
A wireless IC element connected to the power feeding part of the metal pattern ;
With
The dielectric body is composed of an assembly of a plurality of dielectric pieces independent of each other,
The dielectric piece is integrated by the film disposed over the upper surface, the side surface and the lower surface of the dielectric element body,
The metal pattern is bonded to the dielectric element body via the film on the upper surface and the lower surface of the dielectric element body, and between the side surface of the dielectric element body and the film. There is a gap ,
The metal pattern provided on the lower surface of the dielectric body and the curved surface of the metal body are electrically connected via a capacitance or directly;
It is characterized by.

  In the wireless IC device, since the radiator is formed of a flexible metal pattern and the dielectric element body is composed of an assembly of a plurality of independent dielectric pieces, a curved article Even when it is attached to the surface of the (metal body), the dielectric element body and the radiator follow the curved surface, and stress concentration between the element body and the radiator is avoided. Thereby, fluctuations in communication characteristics due to detachment of the radiator, distortion of the radiator, and the like are suppressed, and communication reliability is not impaired. Further, by attaching the wireless IC device to the metal body, the metal body functions as a radiating element, and the communication distance is increased.

  According to the present invention, even when attached to a curved surface, separation between the element body and the radiator does not occur, and fluctuations in communication characteristics can be suppressed.

1 shows a wireless IC device according to a first embodiment, wherein (A) is a perspective view showing a state in which dielectric pieces constituting a dielectric body are separated, and (B) is a view showing a dielectric body by assembling the dielectric pieces. FIG. 4C is a perspective view showing a state before the metal pattern is wound around the dielectric element body, FIG. 4D is a perspective view showing the state where the metal pattern is wound, and FIG. FIG. 4F is a perspective view showing a state in which the wireless IC element is mounted on the radiator. The wireless IC device which is 1st Example shows the attachment state to the articles | goods, (A) is sectional drawing which shows the state before attachment, (B) is sectional drawing which shows the state after attachment. The wireless IC device which is 2nd Example is shown, (A) is a perspective view which shows the state which assembled the dielectric small piece, and comprised the dielectric element body, (B) is before winding a metal pattern around a dielectric element body. The perspective view which shows the state of (1), (C) is the perspective view which shows the state which wound the metal pattern, (D) is DD sectional drawing of (C). The wireless IC device which is a 3rd Example is shown, (A) is a perspective view which shows the state which assembled the dielectric small piece, and comprised the dielectric element body, (B) is before winding a metal pattern around a dielectric element body. The perspective view which shows the state of (1), (C) is a perspective view which shows the state which wrapped the dielectric element | base_body with the film, (D) is DD sectional drawing of (C). The wireless IC device which is 4th Example is shown, (A) is a perspective view which shows the state which packaged the dielectric body with the packaging material, (B) is sectional drawing. It is sectional drawing which shows the radio | wireless IC device which is 5th Example. It is sectional drawing which shows the radio | wireless IC device which is 6th Example. 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.

It will be described below with reference to the accompanying drawings embodiments of a wireless IC device according to the present invention. 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)
The wireless IC device 10A 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, and a metal pattern 30 functioning as a radiator, The flexible resin film 38 that holds the metal pattern 30 and the wireless IC element 50 are used.

  The dielectric body 20 is composed of a rectangular dielectric piece 21 (which may be insulating or magnetic) such as a fluorine-based resin material or a urethane-based resin material, as shown in FIG. Are independent of each other. As shown in FIG. 1B, these dielectric pieces 21 are arranged and assembled to form a rectangular parallelepiped-shaped dielectric element body 20. The metal pattern 30 is made of a conductive material such as flexible copper foil or aluminum foil, and is stuck on the film 38 via an adhesive. The film 38 may be a double-sided tape.

  As shown in FIG. 1C, a film 38 having a metal pattern 30 is attached to the upper surface of the dielectric body 20, and the film 38 is attached to the side surface and the lower surface of the dielectric body 20 together with the metal pattern 30. Bend along. Thus, the dielectric pieces 21 are integrated (see FIG. 1E). The metal pattern 30 is arranged to extend from the upper surface of the dielectric element body 20 to the lower surface via the side surface, and is composed of the upper surface electrode 31, the side surface electrode 32, and the lower surface electrode 33.

  An opening 34 and a slit 35 are formed in the upper surface electrode 31, and the wireless IC element 50 is mounted on the power feeding portions 35 a and 35 b that are opposed to the slit 35 (see FIG. 1F). The wireless IC element 50 processes a high-frequency signal, and details thereof will be described in detail below with reference to FIGS. The coupling between the wireless IC element 50 and the power feeding portions 35a and 35b is electromagnetic direct coupling or direct electrical coupling (DC connection) by solder bumps.

  In the wireless IC device 10A having the above configuration, when a predetermined high-frequency signal is transmitted from the wireless IC element 50 to the power feeding units 35a and 35b, current is concentrated around the opening 34. This current concentration portion functions as a loop-shaped magnetic field electrode having a predetermined length, and has a predetermined potential difference with respect to the power feeding portions 35a and 35b. A predetermined potential difference of the loop-shaped magnetic field electrode is transmitted to the upper surface electrode 31, and the upper surface electrode 31 operates as a patch antenna due to the potential difference with the lower surface electrode 33. In this manner, the characteristics (for example, wideband frequency characteristics) of the signals supplied from the power feeding units 35a and 35b can be transmitted from the metal pattern 30 to the outside as they are. Similarly, when the metal pattern 30 receives a high frequency from the outside, a current is induced around the opening 34, and power is supplied from the power supply units 35 a and 35 b to the wireless IC element 50. In this case, the loop-shaped magnetic field electrode matches the impedance between the wireless IC element 50 and the metal pattern 30.

  The electromagnetic field radiation from the metal pattern 30 alone is weak and can be communicated only over a short distance. As shown in FIG. 2, when the wireless IC device 10 </ b> A is attached to the metal body 40 via the adhesive layer 41, the metal pattern 30 (the lower surface electrode 33) is capacitively coupled to the metal body 40, A strong electromagnetic field is radiated in the direction, and communication with a reader / writer at a distant position becomes possible. The capacity formed between the metal pattern 30 and the metal body 40 may be infinite. In other words, the lower surface electrode 33 may be directly electrically connected to the metal body 40.

  In the wireless IC device 10A, the radiator is formed of a flexible metal pattern 30, and the dielectric element body 20 is an assembly of dielectric pieces 21 independent of each other, and the pieces 21 slide on each other. Since it is possible, even if it is a case where it attaches to the surface of the curved metal body 40 (for example, gas cylinder), the dielectric body 20 and the metal pattern 30 will follow a curved surface, Stress concentration with the metal pattern 30 is avoided. Thereby, fluctuations in communication characteristics due to peeling, distortion, etc. of the metal pattern 30 are suppressed, and communication reliability is not impaired.

  Furthermore, in the first embodiment, the width dimension of the metal pattern 30 is formed smaller than the width dimension of the dielectric body 20. In other words, the metal pattern 30 is bonded (adhered) to the inside of the ridge portions 20a and 20b (see FIG. 1C) of the dielectric element body 20. This makes it difficult for the metal pattern 30 to be peeled from the side portion.

  Further, if the metal pattern 30 is provided on the film 38, the wireless IC element 50 can be mounted on the metal pattern 30 at a stage before being mounted on the dielectric body 20, which is advantageous in the manufacturing process. . In addition, without forming the opening 34 and the slit 35 in the upper surface electrode 31 of the metal pattern 30, the upper surface electrode 31 may be divided into two, and the wireless IC element 50 may be coupled using the divided portion as a power feeding unit.

  In addition, the upper surface electrode 31 and the lower surface electrode 33 of the metal pattern 30 are bonded to the upper and lower surfaces of the dielectric body 20 via the film 38, but the portion where the side electrode 32 is located is not bonded, and the gap 25 Is formed (see FIG. 1E). Thus, when the wireless IC device 10A is attached to the curved surface of the metal body 40 and the dielectric body 20 is curved, the gap 25 is slightly crushed. That is, the tensile force acting on the side electrode 32 when the dielectric element body 20 and the metal pattern 30 are bent is absorbed. Only one of the upper surface electrode 31 and the lower surface electrode 33 may be bonded to the dielectric element body 20.

(Refer to the second embodiment, FIG. 3)
As shown in FIG. 3B, the wireless IC device 10B according to the second embodiment has the opening 34 and the slit 35 of the metal pattern 30 functioning as a radiator disposed in the central portion of the upper surface electrode 31, and the upper surface electrode 31. The dielectric element body 20 was arranged in a loop shape by the pair of side surface electrodes 32 and the lower surface electrode 33 (see FIG. 3D). Other configurations are the same as those of the first embodiment.

  That is, a film 38 having a metal pattern 30 is attached to the upper surface of the dielectric element body 20 so that the opening 34 is located at the center, and both end portions are bent from the side surface of the dielectric element 20 along the lower surface and attached. To wear. In this case, the lower surface electrode 33 is opposed to the central portion through the slit 33a. Further, the side electrode 32 is not bonded to the side surface of the dielectric body 20, and a gap 25 is formed.

  The operational effects of the second embodiment are as described in the first embodiment. In particular, in the second embodiment, the lower surface electrode 33 divided into two by the slit 33a is capacitively coupled to the metal body 40 and functions as a loop-shaped radiator.

(Refer to the third embodiment, FIG. 4)
As shown in FIG. 4A, the wireless IC device 10C according to the third embodiment has a rectangular parallelepiped shape by arranging and assembling dice-shaped dielectric pieces 22 such as a fluorine resin material and a urethane resin material. The dielectric body 20 is configured. The dielectric pieces 22 are independent in a state where four surfaces in contact with each other can slide. Also, a wide flexible resin film 38 for holding the metal pattern 30 is prepared. As shown in FIG. 4C, the dielectric element body 20 is wound from the upper surface to the lower surface through four side surfaces. Packaging. This reliably prevents the dielectric pieces 22 from being scattered.

  Other configurations in the third embodiment are the same as those in 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. 5B, the wireless IC device 10D according to the fourth embodiment is a rectangular parallelepiped by packaging spherical dielectric pieces 23 such as a fluorine resin material and a urethane resin material with a packaging material 39. A dielectric body 20 having a shape is configured. The metal pattern 30 is stuck from the upper surface of the packaging material 30 to the lower surface through the side surface.

  Other configurations in the fourth embodiment are the same as those in the first embodiment, and the operation and effects thereof are as described in the first embodiment. In particular, in the fourth embodiment, since the dielectric body 20 is composed of the small spherical pieces 23 that are independent from each other, the followability of the metal body 40 to the curved surface is good.

  In addition, although the packaging material 39 showed what formed by bending one sheet | seat, what closed the opening part of the bag body other than that may be used. For example, the cylindrical bag body used for food packaging may be heat sealed at both ends.

(Refer to the fifth embodiment, FIG. 6)
The wireless IC device 10E according to the fifth embodiment is a first example having a preferable mounting form as shown in FIG. The wireless IC device 10E includes a protective cover 45 that covers the dielectric element body 20, the metal pattern 30, and the wireless IC element 50. The protective cover 45 is attached to the metal body 40 with an adhesive 46 so as to cover the wireless IC device 10E attached to the metal body 40.

  When the metal body 40 is a gas cylinder or the like, it may be left in an open-air or may be handled roughly. Assuming such various cases, the protective cover 45 can effectively protect the dielectric element body 20 and the metal pattern 30 from the surrounding environment and impact.

(See the sixth embodiment, FIG. 7)
The wireless IC device 10F according to the sixth embodiment is a second example having a preferable mounting form as shown in FIG. In the wireless IC device 10F, a double-sided tape 47 is disposed on the back surface of the protective cover 45 shown in the fifth embodiment. The double-sided tape 47 is a means for adhering to the metal body 40, and protects the dielectric body 20 and the metal pattern 30 together with the protective cover 45. The double-sided tape 47 may be a film. In this case, the double-sided tape 47 is bonded to the back surface of the protective cover 45 or the metal body 40 via an adhesive.

(Wireless IC element, see FIGS. 8 to 11)
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. 8, 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. 8 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, 52 are electrically connected to the power supply portions 35a, 35b 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. 9, when the wireless IC element 50 includes the wireless IC chip 51 and the power supply circuit board 65, 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. 10 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 metal pattern 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 impedance matching circuit, that is, the loop-shaped metal pattern 30 can be shortened.

  Next, the configuration of the feeder circuit board 65 will be described. As shown in FIGS. 8 and 9, 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. 11, the feeder circuit board 65 is obtained by laminating, pressing, and firing ceramic sheets 141 a to 141 h made of a dielectric material or a magnetic material. 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 characteristic is lost, and the band is widened near 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 embodiments can be modified in various ways within the scope of the invention.

  In particular, the material of the dielectric body may be a thermosetting resin such as rubber, elastomer or epoxy, a thermoplastic resin such as polyimide, or a ceramic such as LTCC.

  As described above, the present invention is useful for a wireless IC device. In particular, even when the device is attached to a curved surface, the element body and the radiator are not separated from each other, and the communication characteristics are not easily changed. Excellent in terms.

10A to 10F: wireless IC device 20 ... dielectric body 20a, 20b ... ridge portion 21, 22, 23 ... dielectric piece 30 ... metal pattern (radiator)
31, 32, 33 ... electrode 38 ... film 39 ... packaging material
DESCRIPTION OF SYMBOLS 40 ... Metal body 45 ... Protective cover 50 ... Wireless IC element 51 ... Wireless IC chip 65 ... Power feeding circuit board 66 ... Power feeding circuit

Claims (7)

A wireless IC device attached to a curved surface of a metal body,
A dielectric body having an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface;
A metal pattern that functions as a radiator,
A flexible film for sticking and holding the metal pattern;
A wireless IC element connected to the power feeding part of the metal pattern ;
With
The dielectric body is composed of an assembly of a plurality of dielectric pieces independent of each other,
The dielectric piece is integrated by the film disposed over the upper surface, the side surface and the lower surface of the dielectric element body,
The metal pattern is bonded to the dielectric element body via the film on the upper surface and the lower surface of the dielectric element body, and between the side surface of the dielectric element element and the film. There is a gap ,
The metal pattern provided on the lower surface of the dielectric body and the curved surface of the metal body are electrically connected via a capacitance or directly;
A wireless IC device characterized by the above. The wireless IC device according to claim 1, wherein the metal pattern is bonded to an inner side of a ridge line portion of the dielectric body.   3. The dielectric element according to claim 1, wherein the dielectric piece has a rectangular shape, and the dielectric element body is configured by arranging and collecting the rectangular dielectric pieces. Wireless IC device.   3. The wireless IC device according to claim 1, wherein the dielectric piece has a spherical shape, and the dielectric element body is configured by wrapping the spherical dielectric piece. . The wireless IC device according to any one of claims 1 to 4, further comprising a protective member that covers the dielectric element body, the metal pattern, and the wireless IC element.   The wireless IC device according to claim 1, wherein the wireless IC element is a wireless IC chip that processes a predetermined wireless signal.   6. The wireless IC device according to claim 1, wherein the wireless IC element includes a wireless IC chip for processing 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.

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