JP5786618B2 - Wireless IC device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wireless IC device, in particular, a wireless IC device used in an RFID (Radio Frequency Identification) system and a manufacturing method thereof.

  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 the RFID system, an HF RFID system using a 13 MHz band and a UHF band RFID system using a 900 MHz band are generally used. In particular, the UHF band RFID system is promising as an article management system because it has a relatively long communication distance and can read a plurality of tags at once.

  In recent years, RFID systems are being applied to the medical field. For example, Patent Documents 1, 2, and 3 propose that a UHF band tag be attached to a surgical gauze. This is to prevent accidents such as leaving the gauze in the patient's body by attaching a tag for the UHF band to the gauze and recognizing it with a reader / writer.

  In such a medical field, it is preferable that the RFID tag has no corners in order to prevent the gauze and the human body from being caught. In order to eliminate the corner portion, it is conceivable to seal the wireless IC element 250 by potting it with a resin 251 as shown in FIG. However, when the base material sheet 210 and the antenna element 230 are bent when the resin 251 is sealed, as shown in FIG. 13B, a crack 251a enters the fixing portion of the resin 251 to the antenna element 230. As shown in FIG. 13C, there is a problem that a crack 251b enters a thin portion of the resin 251 and the wireless IC element 250 is damaged, for example, a connection failure occurs with the antenna element 230.

JP 2002-355258 A Japanese Patent Laid-Open No. 2004-121212 JP 2011-015395 A

  An object of the present invention is to prevent the wireless IC element from being exposed to the outside directly and to prevent the wireless IC element from being damaged as much as possible even if the base sheet or the antenna element is bent. It is to provide a device and a manufacturing method thereof.

The wireless IC device according to the first aspect of the present invention is:
A flexible antenna element provided on a rectangular base sheet in plan view having flexibility;
A wireless IC element joined to the antenna element;
A flexible cover sheet attached to the base sheet and / or the antenna element so as to cover the wireless IC element;
With
The cover sheet is adhesively fixed to the base sheet and / or the antenna element at a predetermined distance from the wireless IC element only at the longitudinal end of the base sheet, and the wireless It is not fixed on the top surface of the IC element, and a gap is formed at least on the side of the wireless IC element.
It is characterized by.

A method for manufacturing a wireless IC device according to the second aspect of the present invention includes:
Providing a flexible antenna element divided by slits in a rectangular base sheet in plan view having flexibility;
Bonding a plurality of wireless IC elements to the antenna element at equal intervals so as to straddle the slit;
The cover sheet having flexibility is fixed only at the end portion in the longitudinal direction of the base sheet, at a position away from the wireless IC element by a predetermined distance, and on the top surface of the wireless IC element. The step of adhering and fixing to the base sheet and / or the antenna element so as to form a gap at least on the side of the wireless IC element,
Cutting the base sheet, the antenna element and the cover sheet at equal intervals with the wireless IC element in between;
It is provided with.

  The wireless IC device is attached to, for example, a surgical gauze and communicates with a reader / writer of an RFID system to prevent an accident such as leaving the gauze in the patient's body. In the wireless IC device, since the wireless IC element is covered with a flexible cover sheet, the corners of the wireless IC element are hidden, so that the wireless IC element is not caught on the gauze or the human body. Further, since the cover sheet is adhesively fixed to the base sheet and / or the antenna element at a predetermined distance from the wireless IC element, and a gap is formed at least on the side of the wireless IC element, Even if the base sheet or the antenna element is bent, excessive stress does not act on the wireless IC element, and the wireless IC element is prevented from being damaged as much as possible.

  According to the present invention, it is possible to avoid exposing the corner portion of the wireless IC element directly to the outside and avoid damaging the wireless IC element as much as possible even if the base sheet or the antenna element is bent, Reliability is improved.

It is a perspective view which shows the radio | wireless IC device which is one Example. It is sectional drawing which shows the said wireless IC device. (A), (B), (C) is a top view which shows the various sticking states of a cover sheet. (A), (B) is sectional drawing which shows the curved state of the said wireless IC device. (A) is sectional drawing which shows the other example of the said wireless IC device, (B) is sectional drawing which shows the curved state of this wireless IC device. 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 is explanatory drawing which shows the manufacturing process of the said wireless IC device. It is a disassembled perspective view which shows the structure which attaches the said wireless IC device to gauze. The state which attached the said radio | wireless IC device to the gauze is shown, (A) is a top view, (B) is sectional drawing. (A) Sectional drawing which shows the wireless IC device which is a comparative example, (B), (C) is sectional drawing which shows the damage of the wireless IC element in this comparative example.

  Embodiments of a wireless IC device and a manufacturing method thereof 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.

(Wireless IC device, see FIGS. 1 to 5)
A wireless IC device 1 according to one embodiment is used for UHF band communication, and as shown in FIGS. 1 and 2, an antenna element 30 provided on a flexible base sheet 10; A wireless IC element 50 connected to the antenna element 30 and a flexible cover sheet 40 attached to the antenna element 30 so as to cover the wireless IC element 50 are provided, and configured as a so-called RFID tag.

  The base sheet 10 preferably has, for example, heat resistance and chemical resistance, and a thermoplastic resin material such as polyimide or PET can be suitably used. The antenna element 30 is formed on the base material sheet 10 so as to have flexibility by a metal film mainly composed of silver, copper, aluminum or the like provided on almost the entire surface of the sheet 10. The antenna element 30 is divided by a slit 31 at the central portion in the long side direction, and the wireless IC element 50 is connected and fixed to the antenna element 30 so as to straddle the slit 31. That is, the antenna element 30 functions as a dipole radiating element. Although not shown, a protective film such as a resist or a coverlay is provided on the surface of the antenna element 30 so as to cover the antenna element 30.

  The wireless IC element 50 processes an RF signal, and details thereof will be described later with reference to FIGS. The coupling between the wireless IC element 50 and the end of the antenna element 30, that is, the end divided by the slit 31 (feeding portions 30a, 30a) is an electric field coupling or an electrical direct coupling (DC connection) such as a solder bump. is there. Specifically, the wireless IC element 50 is obtained by mounting the wireless IC chip 51 on the power supply circuit board 65 and sealing the wireless IC chip 51 with a resin material 55. However, the power supply circuit board 65 is not necessarily required, and the wireless IC chip 51 may be joined to the antenna element 30 alone.

  The cover sheet 40 is made of a resin material (for example, a PET film) having the same properties as the base sheet 10, and has an antenna at a location separated from the wireless IC element 50 by a predetermined distance G (see FIG. 2). An air gap H is formed in the side portion of the wireless IC element 50 as shown in FIG. The cover sheet 40 is preferably transparent or translucent because the joining state of the wireless IC element 50 to the antenna element 30 can be visually recognized.

  In the present embodiment, the base sheet 10 and the antenna element 30 have substantially the same shape in plan view, but the base sheet 10 has a larger area in plan view than the antenna element 30. May be. In this case, the cover sheet 40 may be bonded to the base sheet 10, or may be bonded across the base sheet 10 and the antenna element 30.

  3A, 3B, and 3C show various sticking states of the cover sheet 40 having a rectangular shape in a plan view, and are fixed with an adhesive 41 at the hatched portions. FIG. 3A shows a state where the antenna element 30 is attached to both ends in the long side direction. FIG. 3B shows a state of being attached to the antenna element 30 in a frame shape (that is, at four sides). FIG. 3C shows a state where the antenna element 30 is attached to both side portions in the long side direction.

  Here, the communication operation of the wireless IC device 1 will be schematically described. When a predetermined high-frequency signal is transmitted from the wireless IC element 50 to the antenna element 30 through the power feeding units 30a and 30a, the antenna element 30 is directly connected to the outside. To be emitted. Similarly, when the antenna element 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 30a. As a result, the wireless IC element 50 communicates with a reader / writer (not shown).

  In the wireless IC device 1, the wireless IC element 50 is joined to the power feeding portions 30 a and 30 a that are the ends of the antenna element 30, and the cover sheet 40 holds a gap G at both ends so as to cover the wireless IC element 50. Are fixed by bonding. The cover sheet 40 may be simply in contact with the top surface of the wireless IC element 50 without being fixed (see FIG. 4), or may be adhesively fixed to the top surface of the wireless IC element 50 via an adhesive 42. (See FIG. 5).

  As shown in FIG. 4A, when the base sheet 10 and the antenna element 30 are bent into a convex shape, the cover sheet 40 is also deformed into a convex shape. Pressed. However, since the elongation of the cover sheet 40 is slightly absorbed by the presence of the gap H, the stress acting on the wireless IC element 50 from the cover sheet 40 is relieved. Further, when the base sheet 10 and the antenna element 30 are bent into a concave shape as shown in FIGS. 4B and 5B, the cover sheet 40 is bonded to the top surface of the wireless IC element 50. When there is no cover (see FIG. 4B), the cover sheet 40 is separated from the wireless IC element 50, so that no pressing force acts on the wireless IC element 50 from the cover sheet 40. Even when the cover sheet 40 is bonded and fixed to the top surface of the wireless IC element 50 (see FIG. 5B), the cover sheet 40 bends due to the presence of the gap H, so the wireless IC A large pressing force does not act on the element 50.

  That is, although the wireless IC element 50 is covered with the cover sheet 40, the presence of the gap H causes an unreasonable stress even if the base sheet 10 or the antenna element 30 is bent. Thus, the wireless IC element 50 is prevented from being damaged.

(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 feeding portions 30a and 30a of the antenna element 30 through 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 antenna element 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 element 30 and supplies the received high frequency signal to the wireless IC chip 51 via the antenna element 30. 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 antenna element 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 power feeding circuit 66 described above, the inductance elements L1 and L2 are wound in opposite directions, and a current in the opposite direction due to the differential signal flows through the inductance elements L1 and L2, so that the magnetic field generated in the inductance elements L1 and L2 Is offset. 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 power feeding circuit 66 (inductance elements L1, L2) is coupled to the antenna element 30, a reverse current is excited in the antenna element 30, and the antenna element 30 operates with a potential difference due to the current.

  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.

(Manufacturing process of wireless IC device, see FIG. 10)
Next, an example of a method for manufacturing the wireless IC device 1 will be described with reference to FIG. This manufacturing method is based on a so-called multi-chip method in which a plurality of wireless IC devices are manufactured as a collective substrate and then cut one unit at a time.

  First, as step a, the antenna element 30 divided by the slits 31 is provided on the base sheet 10 having a large area with a metal film. Next, as step b, the plurality of wireless IC elements 50 are joined on the antenna element 30 at equal intervals so as to straddle the slit 31. In step c, a cover sheet 40 having a large area is placed on the antenna element 30 and attached. As described above, the cover sheet 40 is attached at a location separated from each wireless IC element 50 by a predetermined gap G (see FIG. 2), and a gap H is formed on the side of the wireless IC element 50. Processed to form.

  Next, the carrier tape 20 is stuck on the back surface of the base material sheet 10 as a process d. As step e, as shown by the cut line C, the wireless IC device 1 is cut into one unit of wireless IC device 1 at equal intervals. At this time, the base sheet 10, the antenna element 30, and the cover sheet 40 are cut, and the carrier tape 20 is not cut. As described above, when the wireless IC devices 1 are gathered on the carrier tape 20, the wireless IC devices 1 are collectively communicated with a reader / writer (not shown) to evaluate the characteristics.

(Refer to Fig. 11 and Fig. 12)
Next, a mode in which the wireless IC device 1 is attached to an article will be described. Here, the article is specifically a surgical gauze 70. That is, as shown in FIGS. 11 and 12, the wireless IC device 1 sandwiched between the nonwoven fabrics 71 and 72 is sewn into a specific portion of the gauze 70. The sewing location is indicated by a dotted line D in FIG. The sewing location is not limited to this position. Alternatively, the wireless IC device 1 may be attached to the gauze 70 by thermocompressing appropriate portions around the nonwoven fabrics 71 and 72. The wireless IC device 1 may be sandwiched between the gauze 70 and the nonwoven fabric 71. That is, the nonwoven fabric 72 located between the wireless IC device 1 and the gauze 70 may be omitted.

  Even if the gauze 70 is bent, the wireless IC element 50 is not damaged, and since the rigid wireless IC element 50 is covered with the flexible cover sheet 40, the wireless IC element 50 is not damaged. The corners of the element 50 are hidden, and the wireless IC element 50 is not caught on the gauze 70 or the human body. Further, the wireless IC element 50 is also covered with the nonwoven fabrics 71 and 72, and is not caught on other articles. Furthermore, after using a large number of gauze 70 in the operation, by checking the wireless IC devices 1 one by one with a reader / writer, it is possible to prevent an accident such as leaving the gauze 70 in the patient's body. .

(Other examples)
The wireless IC device and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments, and can be variously modified within the scope of the gist.

  In particular, the material, shape, and size of the base sheet, cover sheet, and antenna element may be appropriately selected according to the application. Further, the size of the gap G and the gap H is arbitrary. Alternatively, the shape of the antenna element is arbitrary, and may be a meander shape or a loop shape. Further, the article to which the wireless IC device is attached is not limited to the surgical gauze but may be clothing or various fabric products, and the wireless IC device can be suitably used for an article having flexibility.

  As described above, the present invention is useful for a wireless IC device, and is particularly excellent in that the corner portion of the wireless IC element is not directly exposed to the outside and damage to the wireless IC element can be avoided as much as possible.

DESCRIPTION OF SYMBOLS 1 ... Wireless IC device 10 ... Base material sheet 30 ... Antenna element 31 ... Slit 40 ... Cover sheet 50 ... Wireless IC element 51 ... Wireless IC chip 65 ... Power feeding circuit board 70 ... Gauze H ... Gap part

Claims (6)

A flexible antenna element provided on a rectangular base sheet in plan view having flexibility;
A wireless IC element joined to the antenna element;
A flexible cover sheet attached to the base sheet and / or the antenna element so as to cover the wireless IC element;
With
The cover sheet is adhesively fixed to the base sheet and / or the antenna element at a predetermined distance from the wireless IC element only at the longitudinal end of the base sheet, and the wireless It is not fixed on the top surface of the IC element, and a gap is formed at least on the side of the wireless IC element.
A wireless IC device characterized by the above.   The wireless IC device according to claim 1, wherein the base sheet is attached to a flexible article. 3. The wireless IC according to claim 1, wherein the antenna element is a dipole type divided by a slit, and the wireless IC element is connected so as to straddle the slit. device. The wireless IC device according to any one of claims 1 to 3 , wherein the wireless IC element is a wireless IC chip that processes a predetermined wireless signal. The wireless IC device includes a wireless IC chip that processes a predetermined wireless signal, to consist of a feeder circuit board including a feeder circuit having a predetermined resonant frequency, one of claims 1 to 3, characterized in The wireless IC device according to 1. Providing a flexible antenna element divided by slits in a rectangular base sheet in plan view having flexibility;
Bonding a plurality of wireless IC elements to the antenna element at equal intervals so as to straddle the slit;
The cover sheet having flexibility is fixed only at the end portion in the longitudinal direction of the base sheet, at a position away from the wireless IC element by a predetermined distance, and on the top surface of the wireless IC element. The step of adhering and fixing to the base sheet and / or the antenna element so as to form a gap at least on the side of the wireless IC element,
Cutting the base sheet, the antenna element and the cover sheet at equal intervals with the wireless IC element in between;
A method of manufacturing a wireless IC device, comprising:

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