JP2014067235A - Rfid tag and rfid tag system for lamination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an RFID tag for lamination which is improved in its reading performance when being used as a tag for lamination, while the RFID tag reduces its cost and improves the usability.SOLUTION: An RFID tag for lamination includes: an insulating base material; an antenna disposed on the base material; and an IC chip disposed in a terminal unit provided in the antenna. The antenna includes: a matching circuit unit; and a radiation unit, and the chip has reading sensitivity of -17 dBm or less.

Description

  The present invention relates to a radio frequency identification (RFID) tag and an RFID tag system that are excellent in communication characteristics, cost-effective and easy to use even in applications that are used in close contact with each other.

  In recent years, a non-contact type individual identification system using an RFID tag is used in many business forms such as manufacturing, distribution, sales, security management, and recycling as a system for managing the entire life cycle of an object. In particular, radio frequency type IC tags using UHF waves and microwaves are attracting attention due to the feature that an IC chip is attached to an antenna and a communication distance of several meters can be realized. System construction is underway for management and product history management.

  On the other hand, application to the management of a large amount of paper documents and files, electronic recording media such as CDs and DVDs is also considered, but these products are often stacked and handled in close contact. In such applications, when RFID tags are attached to individual products in order to realize logistics and management of large quantities of products, radio wave interference occurs between the RFID tags in close contact with each other, and reading performance by a reader There is a problem that decreases.

  For this reason, by providing an antenna electrically connected to the IC chip and an auxiliary antenna formed via an insulating base material, an electrostatic coupling effect of high-frequency current is generated, and the communication distance is increased. Or a technique for reducing radio wave interference when a plurality of RFID tags are in close contact with each other (Patent Document 1).

JP 2008-117165 A

  However, in the above prior art, although the reading performance when used as a tag for stacking can be improved, a double-sided plate provided with antennas on both sides of an insulating base is used, so the antenna is provided only on one side of the insulating substrate. As compared with the case of using a single-sided plate provided with a problem, there is a problem that the cost increases accordingly.

  Even when using a single-sided plate, it may be possible to improve the reading performance by increasing the output of the reader. However, there are problems in handling such as the need to notify the Radio Law when using the reader. is there.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is capable of reducing the cost and improving the usability while improving the reading performance when used as a tag for stacking, and the RFID tag and RFID tag capable of improving usability The purpose is to provide a system.

The present invention relates to the following.
1. An RFID tag having an insulating substrate, an antenna disposed on the substrate, and an IC chip disposed on a terminal portion provided on the antenna, wherein the antenna includes a matching circuit portion and a radiation portion And the IC chip has a read sensitivity of −17 dBm or less.
2. Item 2. The RFID tag for stacking according to item 1, wherein the maximum width of the antenna is 0.1 to 3.5 mm.
3. Item 3. The RFID tag for stacking according to item 1 or 2, wherein the maximum length of the antenna is 45 to 90 mm.
4). Item 4. The RFID tag for stacking according to any one of Items 1 to 3, wherein the radiation part is a meander.
5. Item 5. The RFID tag according to any one of Items 1 to 4, wherein the antenna is formed only on one side of the substrate.
6). Item 6. The RFID tag for stacking according to any one of Items 1 to 5, wherein the operating frequency of the chip is 0.86 to 0.96 GHz.
7). Item 7. A stackable RFID tag system comprising the stackable RFID tag according to 1-6 and a reader whose output is 250 mW or less.

  According to the present invention, it is possible to provide a stackable RFID tag and an RFID tag system capable of reducing cost and improving usability while improving reading performance when used as a stackable tag.

It is a top view which shows the RFID tag of this invention. It is the top view to which a part of RFID tag of the present invention was expanded. It is a top view explaining the maximum length and the maximum width of the antenna of the RFID tag of the present invention. It is a top view which shows the example of the shape of the radiation | emission part of the antenna of the RFID tag of this invention. It is a top view which shows the shift | offset | difference of the radiation | emission part at the time of laminating | stacking the RFDI tag of this invention. It is sectional drawing of the elongate base material which bonded together the aluminum foil used for manufacture of the RFID tag of this invention. It is the top view and sectional drawing at the time of etching the aluminum foil of a elongate base material, and forming an antenna. It is a top view explaining the width | variety, length, and pitch of an antenna arrange | positioned at the elongate base material. It is the top view and sectional drawing which show an IC chip mounting part. It is the top view and sectional drawing which show an IC chip mounting part. It is sectional drawing of a 3 layer tape. It is a perspective view showing the state which affixed the RFID tag of this invention on the clear file. It is a perspective view which shows the state which is reading the RFID tag of this invention affixed on the clear file with the reader.

  As shown in FIG. 1, the RFID tag of the present invention includes an insulating substrate 30, an antenna 20 disposed on the substrate 30, and an IC chip disposed on a terminal portion 25 provided on the antenna 20. 10, wherein the antenna 20 includes a matching circuit unit 21 and a radiation unit 22, and the IC chip 10 has a read sensitivity of −17 dBm or less. Can be mentioned.

  An RFID tag is a device that sends and receives information to and from an IC chip in a non-contact manner by inducing power to an antenna from a reader or the like wirelessly. The RFID tag of the present invention is particularly effective when applied to management of a large amount of paper documents and files, electronic recording media such as CDs and DVDs, and the like. In other words, in such applications, products are often stacked and handled in close contact, but according to the RFID tag of the present invention, RFID tags are attached to each product and stacked. Even when used in a state, it is possible to suppress a decrease in reading performance by the reader.

  An insulating substrate is a substrate that supports an antenna as a conductor while having insulation. Any insulating material can be used without any particular limitation, but a film-like material is preferable because it is thin, lightweight, and easy to handle. Moreover, the thing provided with the conductor used as an antenna is more preferable at the point which formation of an antenna is easy. Examples of such an insulating substrate include those obtained by bonding a metal foil such as an aluminum foil or a copper foil to the surface of an insulating film such as polyethylene naphthalate (PEN) or polyethylene terephthalate (PET).

  An antenna is used to receive (receive) power by electromagnetically coupling with an RFID reader or the like, transmit it to the chip, operate the chip, or transmit (transmit) the power from the IC chip to the reader or the like as an electromagnetic wave. A conductor pattern. The antenna may be arranged on both sides of the insulating base material or only on one side, but it is preferable to arrange the antenna only on one side in terms of cost reduction.

  The antenna has a matching circuit section and a radiation section. Here, the matching circuit unit performs matching (matching) with the characteristic impedance of the IC chip, whereby the power from the radiating unit is efficiently transmitted to the IC chip, or the power from the IC chip is transmitted. It tells the radiating section. The radiating unit receives (receives) a radio wave from an RFID reader, transmits an electric signal generated by the IC chip as a radio wave, and transmits (transmits) the signal to a reader or the like.

  The terminal portion provided in the antenna means a portion connected to the IC chip, and is provided at an end portion in the matching circuit portion of the antenna. As shown in FIG. 2, when the IC chip 10 has an electrically independent external terminal (not shown), the dummy chip portion 26 corresponding to the antenna 20 is also provided in the antenna 20 to make the IC chip 10 stronger. It is preferable at the point which can be fixed to.

  An IC chip is a semiconductor integrated circuit, and stores and erases data transmitted to and received from a reader or the like via an antenna. The IC chip needs to have a reading sensitivity of −17 dBm or less. In the present invention, the smaller the reading sensitivity value, the higher the reading sensitivity. For this reason, having a reading sensitivity of −17 dBm or less means having a higher sensitivity than the conventionally used reading sensitivity of about −10 to −15 dBm. When applied to the management of a large amount of paper documents and files, electronic recording media such as CDs and DVDs, etc., RFID tags attached to each product are stacked and in close contact with each other. If there is, since the size and shape are the same, the displacement in the overlapped state is generally small. Therefore, in the RFID using an IC chip having a reading sensitivity of about −10 to −15 dBm, which has been conventionally used, the RFID tag and the reader In many cases, transmission / reception with the communication device is hindered and communication is impossible. However, when viewed from the reader or the like, even if the antennas of adjacent RFID tags are slight, there is a deviation. Since the IC chip has a reading sensitivity of −17 dBm or less, it is possible to transmit and receive between the RFID tag and the reader or the like by using this slight deviation between adjacent RFID tag antennas in a stacked state. Conceivable.

  The maximum width of the antenna is preferably 0.1 to 3.5 mm. Here, the maximum width of the antenna 20 means the maximum width of the outer shape of the antenna including the matching circuit portion 21 and the radiating portion 22 as shown in FIG. Further, the width of the antenna 20 means a length in a direction perpendicular to the longitudinal direction of the antenna 20. In general, the maximum length of the outer shape of the antenna can be shortened by increasing the width of the antenna 20, but on the other hand, when RFID tags are stacked at a narrow interval, radio wave interference between the antennas 20 increases and communication performance decreases. To do. If the antenna 20 has a width of 0.1 to 3.5 mm, radio wave interference can be suppressed to a small level, and good communication performance can be obtained for each RFID tag even in a stacked state. In order to obtain good communication performance, the antenna 20 having a width of 0.5 to 2.5 mm is more preferable, and the antenna 20 having a width of 1.0 to 2.0 mm is most preferable.

  The maximum length of the antenna is preferably 45 to 90 mm. Here, the maximum antenna length means the maximum length of the antenna outer shape in the longitudinal direction of the antenna 20, as shown in FIG. In general, when designing a half-wave dipole antenna, its length is determined by the frequency of the radio wave used, and is about 160 mm in the 0.95 GHz band. However, if the antenna size is large, the RFID tag is expensive to manufacture. . Moreover, when it becomes large with respect to the size of general CD and DVD case, it becomes difficult to attach. Therefore, the length of the antenna 20 is preferably 45 to 90 mm from the viewpoint of attachment to documents including CD and DVD and cost. In order to realize good attachment and cost reduction, the length of the antenna 20 is more preferably 50 to 75 mm, and the antenna 20 having a length of 55 to 65 mm is most preferable.

  The shape of the radiating portion of the antenna is not particularly limited, and a linear shape, a meander shape, a folded shape, or the like can be used, but the radiating portion is preferably a meander. As shown in FIG. 4A, the linear shape means that the radiation portion 23 is rectangular. Further, the meander shape means a meander shape in which the radiating portion 22 repeats the П shape upside down as shown in FIG. 4B. Furthermore, as shown in FIG. 4C, the folded shape means a shape in which the radiating portion 24 is a linear pattern folded at an end portion. When an RFID tag is attached to an adherend such as a plurality of documents, a CD (Compact Disc) or a DVD (Digital Versatile Disc) and stacked, the alignment state of the adherend may be slightly shifted. In that case, as shown in the schematic diagram of FIG. 5, the meander-shaped antenna 20 is shifted in either the vertical direction (the vertical direction of the antenna 20 in the longitudinal direction) or the horizontal direction (the long direction of the antenna 20). The overlapping area of the antennas 20 is greatly reduced, and interference between the antennas 20 can be reduced. Furthermore, even if the circuit length of the antenna 20 is increased, the length of the outer shape of the antenna can be reduced, which is preferable in order to obtain good communication performance.

  The antenna is preferably formed only on one side of the substrate. The RFID tag described in Patent Document 1 includes an antenna electrically connected to an IC chip and an auxiliary antenna formed through an insulating base material, thereby providing an electrostatic coupling effect of high-frequency current. It has been devised to increase the communication distance or reduce the radio wave interference when a plurality of RFID tags are in close contact with each other. However, since it is necessary to form antennas on both surfaces of the insulating base material compared to a method in which the antenna is formed only on one side of the base material, a decrease in productivity and an increase in production cost are inevitable. The antenna is preferably formed only on one side of the substrate in terms of good communication performance and low production cost.

  The operating frequency of the chip is preferably 0.86 to 0.96 GHz. Currently, 13.56 MHz band (HF band) and 0.86-0.96 GHz band (UHF band) are widely used as automatic recognition systems using RFID tags. The 13.56 MHz band is electromagnetic induction communication and requires a coil-type antenna. This coil-type antenna has a feature in which a magnetic flux is passed through the inside of the coil and the RFID tag is operated by the generated induced current. The readability at the time of stacking is excellent, but the antenna needs a two-dimensional area. Therefore, the material cost of the antenna is required and the cost is inferior. Moreover, since it cannot be made into an elongate shape with a width of several mm or less, it is inferior in attachment property to an elongate surface such as a document file, a back cover of a CD, or a DVD case. On the other hand, in the 0.86-0.96 GHz band, radio wave communication is possible, and the aforementioned half-wave dipole antenna or the like can be used. The half-wave dipole antenna can reduce the two-dimensional area of the antenna compared to the 13.56 MHz band and can realize an elongated shape with a width of several millimeters or less. Excellent attachability to elongate surfaces such as covers. Therefore, it is preferable that the operating frequency of the chip is 0.86 to 0.96 GHz in terms of low cost and mountability.

  Hereinafter, preferred embodiments of the present invention will be described. In addition, this invention is not limited to a following example.

  First, as shown in FIG. 6, a long base material in which a hard aluminum foil 32 having a thickness of 20 μm is bonded to the surface using an adhesive 31 to a 25 μm-thick polyethylene terephthalate (PET) which is an insulating film 30. 30 were prepared.

  Next, as shown in FIG. 7, after forming an etching resist on the surface of the aluminum foil 31 by gravure printing, etching is performed with a ferric chloride aqueous solution, and the antenna 20 having a matching circuit with an IC chip on the surface thereof. Formed.

  The detailed dimensions of the antenna will be described with reference to FIG. In this embodiment, the width D of the antenna 20 is 1.5 mm, the length E is 60 mm, and the antenna pitch is 4.8 mm. Here, the antenna pitch refers to the pitch in the longitudinal direction of the antenna 20 arranged on a long base material.

  Next, as shown in FIG. 9, bumps serving as external terminals of the RFID IC chip 10 (trade name: Monza5, manufactured by Impinj) with an operating frequency of 0.86 to 0.96 GHz and a read sensitivity of −17.4 dBm are provided. Then, the antenna 20 was aligned with a predetermined position by a flip chip structure, and was joined by applying an ultrasonic wave.

  Next, as shown in FIG. 10, the gap between the IC chip 10 and the antenna 20 was filled with sealing resin 12 (RC091, manufactured by Hitachi Chemical Co., Ltd.), and heat-cured under conditions of 120 ° C. for 2 hours. Through the above steps, 10,000 IC chips 10 are mounted on an antenna tape (which is a long base material on which the antenna 20 is formed) having a width of 70 mm and a length of about 50 m, and wound around a paper core ( Not shown).

  Next, as shown in FIG. 11, the antenna tape wound around the paper core is unwound little by little, and the gap portion of the antenna 20 is cut in order with a cutting blade, and a long adhesive skin paper 40 and a release paper 42 are removed. A three-layer tape in which the antennas 20 are arranged at a pitch of 10 mm between the attached adhesive materials 43 was produced.

  Next, the three-layer tape having an outer size of 64 mm × 6 mm was half-cut from the surface of the skin paper, and an excess portion was removed, thereby obtaining 10,000 RFID tags arranged in a tape shape.

  As shown in FIG. 12, the RFID tag obtained in the above process is pasted on the same position of 100 clear files 60, and the clear files 60 are aligned while changing the stacking pitch. As shown in FIG. From the spine surface of 60, using a reader (Handy Terminal AT-870-UHF, manufactured by ATID), one round scan was performed at an output of 250 mW.

(Comparative Example 1)
First, an RFID IC chip (trade name: UCODE G2XM, manufactured by NXP) with a read sensitivity of -15.0 dBm was used, and 100 RFID tags obtained in the same manner as in the examples were obtained for the other steps. Next, when the RFID tag reading test was performed in the same manner as in the example, it was not possible to read all of them at a pitch of 3 mm or less.

(Comparative Example 2)
First, an RFID IC chip (trade name: Monza5, manufactured by Impinj) having a read sensitivity of -17.4 dBm was used, and 100 RFID tags obtained in the same manner as in the examples were obtained for the other steps. Next, when the RFID tag reading test was performed in the same manner as in the example, it was not possible to read the entire number at a pitch of 2 mm or less.

Table 1 shows the stacking pitches obtained in Examples, Comparative Example 1 and Comparative Example 2, and the results of reading rate.

1: RFID tag 10: IC chip or chip 11: Bump 12: Sealing resin 20: Transmission / reception antenna or antenna 21: Matching circuit unit 22: Meander type radiation unit or radiation unit 23: Linear type radiation unit or radiation unit 24: Folding Type radiation part or radiation part 25: connection terminal or terminal part 26: dummy terminal or dummy terminal part 30: insulating film or insulating base material or base material 31: adhesive 32: aluminum foil 40: skin paper 41: adhesive material 42: Release paper 43: Adhesive material 50: RFID label 60: Clear file 70: Reader

Claims (7)

  An RFID tag having an insulating substrate, an antenna disposed on the substrate, and an IC chip disposed on a terminal portion provided on the antenna, wherein the antenna includes a matching circuit portion and a radiation portion And the IC chip has a read sensitivity of −17 dBm or less.   The RFID tag according to claim 1, wherein the antenna has a maximum width of 0.1 to 3.5 mm.   The RFID tag according to claim 1 or 2, wherein the antenna has a maximum length of 45 to 90 mm.   4. The stackable RFID tag according to claim 1, wherein the radiation portion is a meander.   The RFID tag according to any one of claims 1 to 4, wherein the antenna is formed only on one side of the substrate.   6. The stackable RFID tag according to claim 1, wherein an operating frequency of the chip is 0.86 to 0.96 GHz.   A stackable RFID tag system comprising the stackable RFID tag according to claim 1 and a reader having an output of 250 mW or less.

Images