RFID tag

Abstract

To propose a RFID tag which can increase communication performance in a specific frequency band compared to a state of an RFID inlet.SOLUTION: A pair of right and left antenna parts 13a, 13a has a meandering structure part 22, in which an antenna wire is folded back at least four times and is meandered with a substantially uniform meandering interval in a left-right direction. Since this configuration can generate a peak of communication sensitivity in an RFID inlet 2 in a higher frequency side (940 to 1040 MHz) higher than a specific frequency band (920 MHz), the communication performance shifts to a lower frequency side and the communication sensitivity becomes higher in the specific frequency band so that the communication performance is improved in an RFID tag 1 sealed by thermal plastic films 3, 3 with a dielectric.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an RFID tag capable of contactless communication. [Background technology]

[0002] RFID tags, which are capable of contactless communication, are used to manage items. For example, as in Patent Document 1, RFID tags are attached to items stored in warehouses or on shelves, and the items' inventory, incoming and outgoing goods, etc. are managed by communicating with a specified input / output device. When such RFID tags are used to manage items, each item can be managed by communicating with the input / output device, eliminating the need to check each item one by one, and reducing the effort and time required for management.

[0003] Such an RFID tag includes an RFID inlet in which an IC chip and an antenna are disposed on a substrate, and the RFID inlet is protected by a protective film or the like, and can transmit and receive signals such as commands and data contactlessly between the RFID inlet and an input / output device (reader / writer) using electromagnetic waves. In detail, the antenna of the RFID inlet generates an induced electromotive force by receiving electromagnetic waves emitted from the input / output device, and receives a signal from the input / output device and transmits a pre-stored signal according to the signal. In this way, the RFID tag and the input / output device can communicate with each other. Here, the frequency band of the electromagnetic waves communicated between the RFID tag and the input / output device is specified in each country, and in Japan, a frequency band (hereinafter referred to as a specific frequency band) around 920 MHz (in the range of 915 to 930 MHz) is used. Therefore, the RFID inlet used in Japan is set so that the distance for communicating electromagnetic waves of the specific frequency band (hereinafter referred to as a communication distance) is at its peak. In general, the communication distance of an RFID inlet changes according to the frequency of the electromagnetic waves, and the communication distance reaches a peak in one or two frequency bands. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-34868 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional RFID tags, the configuration in which the RFID inlet is sandwiched and sealed from the front and back with resin protective films has a problem in that the communication distance by electromagnetic waves in the specific frequency band (920 MHz band) is reduced compared to the state of the RFID inlet. This is because the communication sensitivity (communication distance) is shifted to the lower frequency side due to the dielectric constant of the protective films. More specifically, the communication distance, which peaks in the specific frequency band in the RFID inlet, shifts to the lower frequency side due to the sealing of the protective films, so that the communication distance in the specific frequency band in the RFID tag is reduced compared to the RFID inlet. In this way, the communication sensitivity in the specific frequency band of the RFID tag is reduced compared to the RFID inlet.

[0006] An object of the present invention is to provide an RFID tag that can improve communication performance in a specific frequency band compared to an RFID inlet. [Means for solving the problem]

[0007] The present invention is an RFID tag comprising an RFID inlet having an IC chip and a pair of left and right antenna parts respectively extending to the left and right of the IC chip arranged on one side of a sheet-like substrate, and a thermoplastic resin film which is heat-pressed from both the front and back of the RFID inlet to seal the RFID inlet, wherein the left and right antenna parts of the RFID inlet each have a serpentine structure part in which an antenna wire of a predetermined line width is folded back multiple times to meander in the left-right direction at approximately uniform meandering intervals, and the serpentine structure part is folded back four or more times.

[0008] The inventors of the present invention have conducted intensive research into the above-mentioned problem (lengthening the communication distance in a specific frequency band compared to an RFID inlet) and have come up with the invention of the present invention. In detail, if the communication sensitivity is shifted to the low frequency side by sealing the protective film, it is conceivable to configure the RFID inlet so that the peak of the communication sensitivity occurs at a higher frequency than the specific frequency band (920 MHz band), but this has been difficult. Here, the Q value is an index (value indicating the sharpness of resonance) indicating the quality of the coil (antenna), and as the Q value of the coil increases, the loss at high frequencies decreases, so that the coil can have excellent characteristics as a high-frequency inductor. However, at high frequencies, the skin effect of the electric wire and the hysteresis loss and eddy current loss in the iron core material increase, which act in the direction of lowering the Q value, making it difficult to increase the Q value. As a result, as described above, it has been difficult to generate the peak of the communication sensitivity (communication distance) at the RFID inlet at a high frequency. The inventors of the present invention have invented an antenna configuration that can solve this problem. That is, the antenna of the RFID inlet is composed of a pair of left and right antenna parts each having a meandering structure part in which the antenna wire is folded back multiple times and meanders at approximately uniform meandering intervals in the left and right direction, and the dielectric reactance can be increased by increasing the number of folds of the antenna wire. This increases the inductance and increases the Q value, thereby improving the communication sensitivity at high frequencies. In this way, the present invention has been arrived at, which solves the above-mentioned problems by specifying the number of folds of the meandering structure part of the antenna (left and right antenna parts) of the RFID inlet.

[0009] In the RFID inlet of the present invention, each of the left and right antenna parts has a meandering structure part folded back four or more times, so that the peak of communication sensitivity (communication distance) in the RFID inlet can be generated on the higher frequency side (940 to 1040 MHz) than the specific frequency band (920 MHz band). As a result, the RFID tag of the present invention in which the RFID inlet is sealed with a thermoplastic resin film has a communication sensitivity (communication distance) peak shifted to a lower frequency side than the RFID inlet by the thermoplastic resin film, so that the peak after the shift can be brought closer to the specific frequency band. Therefore, the communication distance of the RFID tag in the specific frequency band is longer than that of the RFID inlet. Therefore, according to the configuration of the present invention, the communication performance in the specific frequency band is improved.

[0010] Here, when the meandering structure has less than four folds, the inductance is not sufficiently improved, making it difficult to improve the high frequency characteristics, which makes it difficult to generate a peak in the communication distance in the RFID inlet at a frequency (940 to 1040 MHz) higher than the specific frequency band, and makes it difficult to stably generate the effect of improving the communication sensitivity (communication distance) in the specific frequency band in the RFID tag.

[0011] In the configuration of the present invention, the number of folds in the meandering structure is preferably 5 or more, so that the effect of improving communication performance can be more stably achieved. Moreover, the number of folds is preferably 11 or less. This is because, as the number of folds increases, the conductor resistance increases and the radiation efficiency is likely to decrease. In other words, taking into consideration the balance between the effect of improving communication performance and the decrease in radiation efficiency that accompanies an increase in the number of folds, it is preferable to set the number of folds to 11 or less.

[0012] In the RFID tag of the present invention described above, it is proposed that the left and right antenna parts of the RFID inlet are configured so that their width in the left-right direction is 0.5 to 1.5 times their vertical width in the direction perpendicular to the left-right direction.

[0013] Here, the antenna part of the RFID inlet has a larger capacitive reactance when its width is reduced, whereas a larger vertical width of the antenna part has a larger dielectric reactance. By balancing the capacitive reactance and dielectric reactance to cancel each other out, the communication sensitivity can be improved. For this reason, in this configuration, by specifying the aspect ratio of the antenna unit, the communication sensitivity peak in the RFID inlet can be more stably generated on the higher frequency side (940 to 1040 MHz) than the specific frequency band (920 MHz band). Therefore, with this configuration, the communication performance in the specific frequency band can be improved more stably.

[0014] Furthermore, if the width of the antenna section is less than 0.5 times its height or more than 1.5 times its height, the balance between the capacitive reactance and the dielectric reactance is lost, making it difficult to stabilize the peak of the communication distance in the RFID inlet at frequencies higher than a specific frequency band (940 to 1040 MHz).

[0015] In the configuration of the present invention, the width of the antenna section is preferably 0.8 to 1.4 times the length, and the peak of the communication distance in the RFID inlet tends to occur more stably at frequencies (940 to 1040 MHz) higher than the specific frequency band.

[0016] In the RFID tag of the present invention described above, it is proposed that the antenna parts on the left and right sides of the RFID inlet have a width in the left-right direction of 25 mm or less.

[0017] In this configuration, a relatively small RFID inlet is provided with an antenna section having a width of 25 mm or less. In such a small RFID inlet, the antenna section is relatively small, so communication performance is relatively low. Therefore, by applying the configuration of the present invention described above to a small RFID inlet, the effects of the present invention described above are more pronounced, and the present invention is extremely useful. In addition, relatively large RFID inlets with an antenna width exceeding 25 mm tend to have relatively high communication performance due to the larger antenna. Therefore, even if the communication performance in a specific frequency band is degraded due to a shift to the low frequency side, there are cases where the communication performance is sufficiently high, and the configuration of the present invention tends not to be required in terms of market value.

[0018] In the RFID tag of the present invention described above, a configuration is proposed in which the antenna portion of the RFID inlet is formed by etching.

[0019] In this configuration, the communication sensitivity of the antenna section in the RFID inlet can be improved, so that the communication performance in a specific frequency band can be further improved. Effect of the Invention

[0020] As described above, the RFID tag of the present invention can improve communication sensitivity (communication distance) in a specific frequency band (920 MHz band) compared to the state of an RFID inlet, thereby improving communication performance in the specific frequency band. [Brief description of the drawings]

[0021] [Figure 1] 1A and 1B are explanatory diagrams showing a front view and a vertical cross-sectional view of an RFID tag 1 of a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the RFID tag 1. [Diagram 3] FIG. 2 is a front view showing an RFID inlet 2 that constitutes the RFID tag 1. [Figure 4] 4 shows an evaluation result showing communication performance between the RFID tag 1 and the RFID inlet 2 of the first embodiment. [Diagram 5] 10A is a front view of an RFID tag 31 according to a second embodiment, and FIG. 10B is a table showing evaluation results of communication performance according to the second embodiment. [Figure 6] 13A is a front view of an RFID tag 41 according to a third embodiment, and FIG. 13B is a table showing evaluation results of communication performance according to the third embodiment. [Figure 7] 1A is a front view of an RFID tag 61 of Comparative Example 1, and FIG. 1B is a table showing evaluation results showing communication performance of Comparative Example 1. [Figure 8] 13A is a front view of an RFID tag 71 of Comparative Example 2, and FIG. 13B is a table showing evaluation results showing communication performance of Comparative Example 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] First to third embodiments of the present invention will be described with reference to the accompanying drawings. The RFID tags 1, 31, and 41 of the first to third embodiments are attached to items stored in a warehouse or on a shelf, and can communicate with a predetermined input / output device to manage the inventory, incoming and outgoing goods, etc. Specifically, they can be attached to processing and assembly jigs used in the manufacturing industry and used to manage these jigs.

[0023] The RFID tag 1 of the first embodiment is formed by overlapping an RFID inlet 2 between two thermoplastic resin films 3, 3 and heat-sealing the thermoplastic resin films 3, 3, as shown in Figs. 1 and 2. The thermoplastic resin film 3 used in this embodiment has a thickness of 0.4 to 0.6 mm, and the thickness of the RFID tag 1 is set to 0.8 to 1.25 mm. The thermoplastic resin film 3 used has a dielectric constant of 2.8 to 3.1. As the thermoplastic resin film 3, in this embodiment, a glycol-modified polyethylene terephthalate (hereinafter referred to as PETG) film is used.

[0024] As shown in Fig. 1(A) and Fig. 3, the RFID inlet 2 is a non-contact, battery-less type that can transmit and receive signals such as commands and data non-contactly using electromagnetic waves such as HF and UHF bands between an input / output device (reader / writer device) (not shown) and an IC chip 12 and a pair of antenna parts 13a, 13a are arranged on one side (front or back) of a thin-film sheet-like substrate 11. Here, the sheet-like substrate 11 has a thickness of 180 to 250 µm, and polyethylene terephthalate (RET), polypropylene (PP), polyacetal (POM), polycarbonate (PC), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), etc. are used, and among these, PET and PP, which have excellent strength and rigidity, are preferably used. The IC chip 12 can electromagnetically store required information and is electrically connected to the antenna 13 (the left and right antenna parts 13a, 13a).

[0025] The left and right antenna parts 13a, 13a are provided extending from the IC chip 12 to the left and right, respectively, and each includes a connection part 21 connected to the IC chip 12, a meandering structure part 22 connected to the connection part 21, and an outer end part 23 connected to the meandering structure part 22. Here, the left and right connection parts 21, 21 are connected to each other and are composed of an antenna wire having the same line width as the meandering structure part 22. The meandering structure part 22 is configured such that an antenna wire having a predetermined line width is folded back multiple times and meanders at approximately uniform meandering intervals in the left-right direction, and the line width of the antenna wire is set to a narrow width (200 to 1000 μm). In the antenna section 13a of the first embodiment, the meandering structure section 22 is composed of straight sections 28 in which the antenna wire is arranged in a substantially straight line in the vertical direction, and substantially U-shaped folded sections 26 that connect adjacent straight sections 28, and has five straight sections 28 and four folded sections 26. In other words, the meandering structure section 22 is configured by folding the antenna wire four times. The outer end section 23 is formed to be wider than the antenna wire, and is provided along the vertical direction perpendicular to the left-right direction (horizontal direction).

[0026] Furthermore, the antenna 13 of this embodiment is designed so that the width W of each antenna section 13a in the left-right direction (horizontal direction) (hereinafter referred to as the width) is 0.5 to 1.5 times (=W / T) the width T of each antenna section 13a in the vertical direction (hereinafter referred to as the vertical width). In other words, the width (=2×W) of the antenna 13 is designed to be 1 to 3 times the vertical width. In the RFID inlet 2 of this embodiment 1, the width W of the antenna section 13a is about 1.3 times the vertical width T. Here, the specific size of this embodiment is that the width of the antenna section 13a is about 21 mm, the vertical width is about 16 mm, and the width of the antenna 13 (total width obtained by adding the left and right antenna sections 13a, 13a) is about 42 mm. Thus, the RFID inlet 2 of this embodiment is small.

[0027] The antenna 13 (the left and right antenna portions 13a, 13a) is made of aluminum or copper and is formed by etching. Since a known method can be used for the etching, details thereof will be omitted.

[0028] An evaluation test was conducted to evaluate the communication performance of the RFID tag 1 of Example 1. The results of this evaluation test are shown in FIG. 4. The evaluation test is a test in which the communication frequency is changed and the communication distance (communication sensitivity) at each frequency is measured, and is conducted both in the state of the RFID inlet 2 and in the state of the RFID tag 1. As shown in FIG. 4, the RFID inlet 2 has two peaks of the communication distance, and the peak near the specific frequency band (920 MHz) occurs near 940 to 950 MHz, which is higher than the specific frequency band. The communication distance of the specific frequency band is lower than the peak. In the RFID tag 1 in which such an RFID inlet 2 is sealed, the graph of the communication distance is shifted to the lower frequency side as a whole. As a result, the above-mentioned peak of the communication distance occurs near 910 MHz, and the communication distance in the specific frequency band (920 MHz) is improved by about 14% compared to the RFID inlet 2. In this way, the RFID tag 1 of the first embodiment has improved communication performance in the specific frequency band (920 MHz) compared to the RFID inlet 2 .

[0029] Next, an RFID tag 31 according to a second embodiment will be described. The RFID tag 31 of the second embodiment is formed by overlapping an RFID inlet 32 ​​between two thermoplastic resin films 3, 3 and heat-sealing the thermoplastic resin films 3, 3, as in the first embodiment. As shown in Fig. 5(A), the RFID inlet 32 ​​includes a sheet-like base material 11, an IC chip 12, and an antenna 33 consisting of a pair of left and right antenna parts 33a, 33a, and the IC chip 12 and the antenna 33 (the left and right antenna parts 33a, 33a) are disposed on one side of the sheet-like base material 11. Here, the thermoplastic resin film 3, the sheet-like base material 11, and the IC chip 12 are the same as those in the first embodiment, and therefore their details will be omitted.

[0030] The left and right antenna parts 33a, 33a each have a connection part 35, a meandering structure part 36, and an outer end part 37, and the IC chip 12 is connected to the connection part 35. The connection part 35 and the meandering structure part 36 are formed by an antenna wire having a narrow width (200 to 1000 μm), and the left and right connection parts 35 are connected to each other. The meandering structure part 36 is connected to the connection part 35, and has a configuration in which 12 straight parts 38 are arranged at approximately uniform meandering intervals in the left and right direction, and adjacent straight parts 38 are connected to each other by a folded part 39. That is, the meandering structure part 36 of this embodiment has 11 folded parts 39 by folding the antenna wire 11 times. The outer end part 37 is formed to be wider than the antenna wire and is provided along the vertical direction.

[0031] The antenna section 33a in Example 2 has a width W that is 0.9 times (=W / T) its length T. Here, the width of the antenna section 33a is about 11 mm, the length is about 12 mm, and the width of the antenna 33 is about 22 mm. Thus, the RFID inlet 32 ​​in this example is small. Also, the antenna 33 (left and right antenna sections 33a, 33a) in Example 2 is also formed by etching, as in Example 1.

[0032] The RFID tag 31 of Example 2 was subjected to an evaluation test similar to that of Example 1. The results are shown in Fig. 5(B). In the state of the RFID inlet 32 ​​of Example 2, the peak of the communication distance (communication sensitivity) occurs at 940 to 980 MHz, while in the RFID tag 31, the peak of the communication distance occurs near 910 MHz, shifting to the lower frequency side. Furthermore, the communication distance is improved compared to the RFID inlet 32. Thus, the communication distance of the RFID tag 31 in the specific frequency band (920 MHz) is improved by about 50% compared to the RFID inlet 32, and the communication performance in the specific frequency band is improved.

[0033] Next, an RFID tag 41 according to a third embodiment will be described. The RFID tag 41 of the third embodiment is formed by overlapping an RFID inlet 42 between two thermoplastic resin films 3, 3 and heat-sealing the thermoplastic resin films 3, 3, as in the first and second embodiments. As shown in Fig. 6(A), the RFID inlet 42 includes a sheet-like substrate 11, an IC chip 12, and an antenna 43 consisting of a pair of left and right antenna parts 43a, 43a, and the IC chip 12 and the antenna 43 (the left and right antenna parts 43a, 43a) are disposed on one side of the sheet-like substrate 11. Here, the thermoplastic resin film 3, the sheet-like substrate 11, and the IC chip 12 are the same as those in the first embodiment described above, and therefore their details will be omitted.

[0034] The left and right antenna parts 43a, 43a each have a connection part 45, a meandering structure part 46, and an outer end part 47, and the IC chip 12 is connected to the connection part 45. The left and right connection parts 45, 45 are formed of antenna wires having a narrow width (200 to 1000 μm) and are connected to each other. The meandering structure part 46 is connected to the connection part 45, and has eight straight parts 48 arranged at approximately uniform meandering intervals in the left and right direction, and adjacent straight parts 48 are connected to each other by a folded part 49. That is, the meandering structure part 46 of this embodiment has seven folded parts 49 by folding the antenna wire seven times. The outer end part 47 is formed by forming the antenna wire into a rectangular frame shape. The antenna portion 43a of the third embodiment has a width W that is about 1.3 times the length T (=W / T), that is, a width of about 21 mm and a length of about 16 mm (the width of the antenna 43 is about 42 mm). The antenna 43 (the left and right antenna portions 43a, 43a) is formed by etching in the same manner as in the first embodiment.

[0035] The RFID tag 41 of Example 3 was subjected to an evaluation test similar to that of Example 1. The results are shown in Fig. 6(B). In the state of the RFID inlet 42 of Example 3, the peak of the communication distance (communication sensitivity) occurs at 1020 to 1030 MHz, while in the RFID tag 31, the peak of the communication distance occurs near 930 to 950 MHz, shifting to the lower frequency side. Furthermore, the communication distance is improved compared to the RFID inlet 42. As a result, the communication distance of the RFID tag 41 in the specific frequency band (920 MHz) is improved by about 60% compared to the RFID inlet 42, and the communication performance in the specific frequency band is improved.

[0036] Next, comparative examples 1 and 2 to be compared with the above-mentioned embodiments 1 to 3 will be described. The RFID tag 61 of Comparative Example 1 is formed by overlapping an RFID inlet 62 between two thermoplastic resin films 3, 3 and heat-sealing them, as in Examples 1 to 3. As shown in Fig. 7(A), this RFID inlet 62 has an IC chip 12 and an antenna 63 composed of a pair of left and right antenna parts 63a, 63a disposed on one side of a sheet-like base material 11. The thermoplastic resin film 3, the sheet-like base material 11, and the IC chip 12 are the same as those in Example 1 described above, and therefore their details will be omitted.

[0037] The left and right antenna parts 63a, 63a each have a connection part 64 and a main surface part 65, and the IC chip 12 is connected to the connection part 64. The left and right connection parts 64 are joined to each other, and the main surface part 65 is formed in a substantially rectangular flat plate shape. The antenna part 63a of Comparative Example 1 does not have the meandering structure part. The antenna part 63a has a width W that is 1.2 times the length T (=W / T), and has a width of about 36 mm and a length of about 30 mm (the width of the antenna 63 is about 72 mm). The antenna 63 of Comparative Example 1 (the left and right antenna parts 63a, 63a) is formed by etching in the same manner as in Examples 1 to 3.

[0038] The RFID tag 61 of Comparative Example 1 was subjected to an evaluation test similar to that of Example 1 described above. The results are shown in Fig. 7(B). In the state of the RFID inlet 62 of Comparative Example 1, the peak of the communication distance (communication sensitivity) occurs at 900 to 930 MHz, while in the RFID tag 61, the peak of the communication distance occurs near 870 MHz, shifting to the lower frequency side. As a result, the communication distance in the specific frequency band (920 MHz) of the RFID tag 61 of Comparative Example 1 is reduced by about 25% compared to the RFID inlet 62, and the communication performance in the specific frequency band is degraded.

[0039] On the other hand, the RFID tag 71 of Comparative Example 2 is formed by overlapping an RFID inlet 72 between two thermoplastic resin films 3, 3 and heat-sealing them, similar to Examples 1 to 3. As shown in Fig. 8(A), this RFID inlet 72 has an IC chip 12 and an antenna 73 composed of a pair of left and right antenna portions 73a, 73a disposed on one side of a sheet-like substrate 11. Note that the thermoplastic resin film 3, the sheet-like substrate 11, and the IC chip 12 are the same as those in Example 1 described above, and therefore their details will be omitted.

[0040] The left and right antenna parts 73a, 73a each include a connection part 75, a meandering structure part 76, and a plane structure part 77, and the IC chip 12 is connected to the connection part 75. The left and right connection parts 75, 75 are formed of antenna wires having a narrow width (200 to 1000 μm) and are connected to each other. The meandering structure part 76 is connected to the connection part 75, and has three straight parts 78 arranged at approximately uniform meandering intervals in the left and right direction, and adjacent straight parts 78 are connected to each other by a folded part 79. The meandering structure part 76 of this comparative example 2 has two folded parts 79 by folding the antenna wire twice. The plane structure part 77 is formed in a substantially rectangular flat plate shape. The antenna portion 73a of Comparative Example 2 has a width W that is about 1.4 times (=W / T) the length T, and is about 27 mm wide and about 19 mm long (the width of the antenna 73 is about 54 mm). The antenna 73 (the left and right antenna portions 73a, 73a) is formed of metal foil (such as aluminum foil or copper foil).

[0041] The RFID tag 71 of Comparative Example 2 was subjected to an evaluation test similar to that of Example 1 described above. The results are shown in Fig. 8(B). In the state of the RFID inlet 72 of Comparative Example 1, the communication distance (communication sensitivity) peaks occur at 920 to 940 MHz and near 1050 MHz. On the other hand, in the RFID tag 71, the communication distance peaks occur near 860 MHz and near 970 MHz, shifting to the lower frequency side. As a result, the communication distance in the specific frequency band (920 MHz) of the RFID tag 71 of Comparative Example 2 is reduced by about 30% compared to the RFID inlet 62, and the communication performance in the specific frequency band is degraded.

[0042] As described above, the RFID tags 1, 31, and 41 of Examples 1 to 3 have improved communication performance in the specific frequency band (920 MHz) compared to the respective RFID inlets 2, 32, and 42, while the RFID tags 61 and 72 of Comparative Examples 1 and 2 have lower communication performance compared to the respective RFID inlets 62 and 72. This is because the RFID inlets 62 and 72 of Comparative Examples 1 and 2 have a peak in communication distance near the specific frequency, while the RFID inlets 2, 32, and 42 of Examples 1 to 3 have a peak in communication distance at a frequency higher than the specific frequency. That is, since the RFID tags 1, 31, 41, 61, and 71 of Examples 1 to 3 and Comparative Examples 1 and 2 are sealed with the thermoplastic resin film 3 of PETG, the communication distance shifts toward the stop frequency side compared to the state of the RFID inlets 2, 32, 42, 62, and 72. As a result, in the comparative examples 1 and 2, the peak of the communication distance occurs near the specific frequency band (920 MHz) in the state of the RFID inlets 62 and 72, and therefore the communication distance in the specific frequency band is reduced in the RFID tags 61 and 71. In contrast, in the configurations of the embodiments 1 to 3, the peak of the communication distance occurs at a frequency higher than the specific frequency band in the state of the RFID inlets 2, 32, and 42, and therefore the communication distance in the specific frequency band is improved in the RFID tags 1, 31, and 41. Here, in the RFID inlets 2, 32, and 42 of the embodiments 1 to 3, the antenna section 13a, 33a, and 43a has the meandering structure section 22, 36, and 76 having four or more folds and the horizontal width is 0.5 to 1.5 times the vertical width, and therefore, as described above, the peak of the communication distance can be generated at a frequency higher than the specific frequency band. As a result, when the peak is shifted to the lower frequency side by sealing with a thermoplastic resin film (PETG) 3, 3 having a predetermined dielectric constant, the communication distance (communication sensitivity) in a specific frequency band can be improved.

[0043] As described above, the RFID tags 1, 31, and 41 of the first to third embodiments are attached to processing and assembly jigs used in the manufacturing industry, and are used to manage these jigs. Some of these jigs are subject to inventory, and inventory work may be performed while they are stored in a warehouse or a storage room. In this case, if the RFID tags 1, 31, and 41 of the present embodiments 1 to 3 are attached to each jig, each jig can be managed by communicating with the input / output device, so that it is not necessary to take out each jig one by one and check it, and the effort and time required for inventory work can be reduced. In particular, the RFID tags 1, 31, and 41 of the present embodiments 1 to 3 improve the communication distance as described above, so that the moving distance required for the worker to enter the communication distance can be shortened. And, even in a relatively large warehouse or storage room, it becomes easy to communicate with the input / output device. Therefore, according to the configurations of the present embodiments 1 to 3, the effect of reducing the inventory work described above is dramatically improved.

[0044] The present invention is not limited to the above-described first and second embodiments, and can be modified as appropriate within the scope of the present invention. For example, in the above-described embodiments, the folded portion is formed in a substantially U-shape, but the present invention is not limited to this, and the folded portion may be, for example, substantially U-shaped (arc-shaped) or substantially V-shaped. [Explanation of symbols]

[0045] 1,31,41 RFID tags 2,32,42 RFID inlet 3 Thermoplastic resin film 11 Sheet-shaped substrate 12 IC chip 13a, 33a, 43a Antenna section 22, 36, 46 Serpentine structure W Width T Vertical width

Claims

1. an RFID inlet having an IC chip and a pair of antenna parts extending to the left and right of the IC chip, respectively, disposed on one surface of a sheet-like substrate; a thermoplastic resin film that is heat-pressed from both sides of the RFID inlet to seal the RFID inlet; Equipped with The left and right antenna parts of the RFID inlet are This RFID tag is characterized in that it has a meandering structure portion in which an antenna wire of a predetermined line width is folded back multiple times to meander in the left-right direction at approximately uniform meandering intervals, and the meandering structure portion is folded back four or more times.

2. The RFID tag according to claim 1, characterized in that the left and right antenna parts of the RFID inlet are formed so that their width in the left-right direction is 0.5 to 1.5 times their height in the direction perpendicular to the left-right direction.

3. 3. The RFID tag according to claim 1, wherein the left and right antenna parts of the RFID inlet have a width in the left-right direction of 25 mm or less.

4. 4. The RFID tag according to claim 1, wherein the antenna portion of the RFID inlet is formed by etching.

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