RFID tag

Abstract

To propose an RFID tag capable of suppressing the deterioration of communication performance while protecting required information printed on a protect film.SOLUTION: An information covering film 5 with the same size as a protect film 4 or smaller is pasted on the surface of a protect film 4 covering an IC tip 14 and an antenna 13. The information covering film 5 to protect the information entry part 17 of the protect film 4 is layered on the IC tip 14 and the antenna 13, and is pasted on the protect film 4 without protruding beyond the protect film. The information covering film 5 can suppress a peeling starting-point and also the deterioration of communication performance according to this configuration.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an RFID tag that is attached to an article and is capable of transmitting and receiving signals in a non-contact manner. [Background technology]

[0002] For example, Patent Document 1 describes an RFID tag having an RFID inlay in which an IC chip and an antenna are disposed on a thin-film inlay substrate, and a protective film that covers the RFID inlay, and the RFID tag is attached to an object by an adhesive layer provided on the back side. Here, the protective film is formed to be slightly larger than the RFID inlay, and covers and protects the entire RFID inlay.

[0003] In such RFID tags, a configuration is known in which required information such as the manufacturer and the serial number is printed on the surface of the protective film, and the protective film is covered with a laminate film that protects the required information. In such a configuration, a laminate film that is one size larger than the protective film is generally used. This allows the laminate film to protect the entire surface of the protective film, and the outer edge of the laminate film is firmly attached to the object to be attached. Here, if the laminate film is slightly larger than the protective film, the width of the outer edge attached to the object to be attached is narrowed due to the step caused by the thickness of the protective film, and it is likely to become a starting point for peeling. In contrast, if the laminate film is one size larger than the protective film, the width of the outer edge attached to the object to be attached is widened, which has the advantage of suppressing the starting point for peeling. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-171341 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional RFID tag, the configuration with the laminate film covering the protective film has a double coating of the IC chip and antenna with the protective film and the laminate film, and therefore communication performance (communication distance) is reduced compared to a configuration covered only with the protective film. This is thought to be due to the dielectric constant of the laminate film, and the conventional configuration was unable to maintain communication performance while protecting the required information printed on the protective film.

[0006] The present invention is capable of solving the above-mentioned problems, and proposes an RFID tag that can protect the required printed information while suppressing a decrease in communication performance. [Means for solving the problem]

[0007] The present invention is an RFID tag comprising an IC chip, an antenna connected to the IC chip, and a protective film covering the IC chip and the antenna and having an information entry section on its surface on which required information is written, and having an adhesive layer on the back surface to be attached to an object, characterized in that the RFID tag comprises an information covering film that is formed to be the same size as or smaller than the protective film, covers the information entry section, overlaps the IC chip and the antenna, and is affixed to the surface of the protective film without protruding outward. Here, the configuration of the present invention includes not only one in which an information covering film is affixed to a protective film with the required information written in the information entry section, but also one in which the required information is written in the information entry section with the information covering film affixed to the protective film.

[0008] In such a configuration, the information covering film affixed onto the protective film can protect the required information written on the protective film, and since the information covering film, which is the same size or smaller than the protective film, is affixed without protruding beyond the protective film, the information film is less likely to become a starting point for peeling and is generally less likely to peel off from the object to which it is attached.

[0009] Furthermore, in this configuration, by attaching an information covering film that is equal to or smaller in size than the protective film, it is possible to suppress a decrease in communication performance. Here, it is known that resin films such as PET used in the protective film degrade the communication performance due to their dielectric constant. Generally, the degradation of communication performance due to the dielectric constant increases as the protective film becomes thicker (communication performance degrades). That is, as in the conventional configuration described above, when a film larger than the protective film is layered to cover the protective film, communication performance is degraded. The inventors of the present invention have studied such conventional configurations and have found that the degradation of communication performance can be suppressed by making the information covering film the same size or smaller than the protective film.

[0010] Thus, according to the configuration of the present invention, in addition to the effect of protecting the necessary information written on the protective film and the effect of preventing it from becoming a starting point for peeling, it is possible to achieve the effect of suppressing a decrease in communication performance.

[0011] In the RFID tag of the present invention described above, a configuration is proposed in which the information covering film is formed with an area of ​​70 to 140% of the outer dimension area of ​​the antenna defined by the outer dimensions of the antenna.

[0012] This configuration was arrived at through further study of the aforementioned knowledge of suppressing the decline in communication performance, and by setting the size of the information covering film to an area ratio of 70 to 140% of the external area of ​​the antenna, the effect of suppressing the decline in communication performance can be stably achieved.

[0013] Here, if the area of ​​the information covering film is smaller than 70% of the outer area of ​​the antenna, the effect of suppressing the communication performance can be obtained, but the area of ​​the information writing section is small, so the amount of information that can be written in the information writing section is limited.On the other hand, if the area is larger than 140%, the effect of suppressing the deterioration of communication performance becomes insufficient, and it becomes difficult to fit the information covering film into the same size as the protective film.

[0014] In this configuration, it is preferable that the area of ​​the information covering film is 80 to 110% of the outer area of ​​the antenna. By setting the area in this range, it is possible to secure an information entry area for writing a sufficient amount of information, and the effect of suppressing the deterioration of communication performance can be more stably achieved.

[0015] In the RFID tag of the present invention described above, a configuration is proposed in which the information covering film is attached to the surface of the protective film so as to overlap the entire IC chip and at least a part of the antenna.

[0016] According to this configuration, the IC chip can be protected by the information covering film, so that damage to the IC chip can be suppressed and stable communication can be performed for a relatively long period of time. Effect of the Invention

[0017] As described above, the RFID tag of the present invention can achieve all of the following effects: protecting the required information written in the information entry section of the protective film by the information covering film; preventing the outer edge of the information covering film from becoming a starting point for peeling; and suppressing communication performance. [Brief description of the drawings]

[0018] [Figure 1] 1A and 1B are a plan view and a cross-sectional view, respectively, showing an RFID tag 1 of the present invention releasably adhered to a release liner 3. FIG. [Diagram 2] FIG. 2 is an exploded perspective view of the RFID tag 1. [Diagram 3] 2 is an explanatory diagram showing the outer dimensions of the antenna 13 of the RFID inlay 2. FIG. [Figure 4] FIG. 2 is a plan view showing RFID tags 1a to 1e according to the respective embodiments. [Diagram 5] FIG. 2 is a plan view showing RFID tags 51a to 51c of comparative examples. [Figure 6] 1 is a table showing (A) the results of evaluating the communication performance of Examples 1 to 3 and Comparative Examples 1 and 2, and (B) the results of evaluating the communication performance of Examples 4 to 6 and Comparative Examples 3 and 4. [Figure 7] FIG. 11 is a plan view showing an RFID tag 1b according to a third embodiment and RFID tags 1f and 1g according to other embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An embodiment of the present invention will be described with reference to the accompanying drawings. The RFID tag 1 of this embodiment is used by attaching it to an object (not shown) via an adhesive layer 11 on the back side. As shown in Figures 1 and 2, the RFID tag 1 includes an RFID inlay 2 having an adhesive layer 11 formed on the back side, a protective film 4 attached to the surface of the RFID inlay 2, and an information covering film 5 attached to the surface of the protective film 4, and a release paper 3 is removably attached to the adhesive layer 11 of the RFID inlay 2. The release paper 3 is peeled off to attach the RFID tag to the object.

[0020] The RFID inlay 2 includes a thin-film inlay substrate 12 having a substantially rectangular shape in plan view, an antenna 13 provided on the surface of the inlay substrate 12, and an IC chip 14 connected to the antenna 13, and an adhesive layer 11 is provided on the back surface of the inlay substrate 12. The RFID inlay 2 is a non-contact, battery-less type that can transmit and receive signals such as commands and data in a non-contact manner using electromagnetic waves such as HF and UHF bands between an input / output device (reader / writer device) not shown. Here, the inlay substrate 12 has a thickness of 100 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 14 can electromagnetically store required information, and is placed on the center of the antenna 13 and electrically connected thereto.

[0021] In such an RFID inlay 2, the antenna 13 is of a so-called dipole type, and as shown in Fig. 3, its outer dimensions of length T and width W are shorter than the length and width of the inlay substrate 12. As a result, the area of ​​the antenna outer dimension region S defined by the length T and width W of the antenna 13 is smaller than the area of ​​the inlay substrate 12, and the antenna 13 is contained within the periphery of the inlay substrate 12 (it does not protrude outward from the inlay substrate 12). The area of ​​the antenna outer dimension region S corresponds to the antenna outer dimension area according to the present invention.

[0022] As shown in Figs. 1 and 2, the protective film 4 is formed in a generally rectangular shape in plan view with the same outer dimensions as the inlay substrate 12, and is superimposed and attached to the surface of the RFID inlay 2 by an adhesive layer 16 provided on the back surface. In this embodiment, the outer periphery of the protective film 4 overlaps the outer periphery of the RFID inlay 2 (the outer periphery of the inlay substrate 12). This protective film is a white, opaque PET or PP film with a thickness of 100 to 250 µm. The adhesive layer 16 of the protective film 4 is different from the adhesive layer 11 of the RFID inlay 2. Specifically, the adhesive layer 11 of the RFID inlay 2 is formed of a hot melt adhesive, while the adhesive layer 16 of the protective film 4 is formed of an emulsion adhesive.

[0023] Such a protective film 4 has an information marking section 17 on its surface where required information such as the manufacturer and serial number is printed. Not only letters and numbers but also optically readable optical codes can be printed on the information marking section 17. Here, since the protective film 4 is white and opaque, the information printed on the information marking section 17 can be easily read.

[0024] 1 and 2, the information covering film 5 is formed in a generally rectangular shape in plan view with smaller outer dimensions than the protective film 4, and is attached to the surface of the protective film 4 by an adhesive layer 19 provided on the back surface. The information covering film 5 covers the information writing section 17 of the protective film 4 to protect the information printed in the information writing section 17, and is made of a transparent PET or PP film. The information covering film 5 is attached without protruding beyond the protective film 4, and overlaps the IC chip 14 and antenna 13 of the RFID inlay 2 via the protective film 4. In this embodiment, the information covering film 5 is arranged so as to cover the entire IC chip 14 and the entire antenna 13.

[0025] The following describes the results of evaluating communication performance for the following specific example of the RFID tag 1 according to the embodiment. The evaluation of communication performance was also performed for a comparative example that was compared with the embodiment.

[0026] As described above, the RFID tag 1 of the first embodiment has an RFID inlay 2 and a protective film 4 that are the same substantially rectangular shape, and are formed by overlapping them (FIGS. 1 and 2). An information covering film 5 that is slightly smaller in size than the protective film 4 is attached to the surface of the protective film 4. As described above, the information covering film 5 covers the information writing section 17 of the protective film 4 and is arranged so as to overlap the entire antenna 13 and the entire IC chip 14. Here, in the configuration of the first embodiment, the outer dimensions of the protective film 4 (RFID inlay 2) are about 97 mm (width) x about 27 mm (length), and the outer dimensions of the antenna 13 are about 90 mm (width W) x about 20 mm (length T). As shown in FIG. 6(A), the outer dimensions of the information covering film 5 are about 96 mm (width) x about 26 mm (length). That is, in the configuration of the first embodiment, the area of ​​the information covering film 5 is about 139% of the area of ​​the antenna outer dimension region S of the antenna 13.

[0027] As shown in Fig. 4(A), the RFID tag 1a of Example 2 has an information covering film 5a smaller in size than that of Example 1. In the configuration of Example 2, the outer dimensions (length and width) of the information covering film 5a are approximately the same as the outer dimensions of the antenna 13, and the information covering film 5a covers the information writing section 17 of the protective film 4 and is attached so as to overlap the antenna 13. Here, as shown in Fig. 6(A), the outer dimensions of the information covering film 5a are approximately 90 mm x approximately 20 mm, and the area of ​​the information covering film 5a is approximately 100% of the area of ​​the antenna outer dimension region S of the antenna 13. Note that the RFID tag 1a of Example 2 is the same as that of Example 1 except for the information covering film 5a, so detailed description will be omitted.

[0028] As shown in FIG. 4(B), the RFID tag 1b of Example 3 has an information covering film 5b smaller in size than those of Examples 1 and 2. In the configuration of Example 3, the vertical dimension of the information covering film 5b is approximately the same as the vertical width T of the antenna 13, and the horizontal dimension is shorter than the horizontal width W of the antenna 13. In this configuration, the information covering film 5b covers the information writing section 17 of the protective film 4, and is disposed so as to overlap the entire IC chip 14 and a part of the antenna 13. Here, as shown in FIG. 6(A), the outer dimensions of the information covering film 5b are approximately 80 mm×approximately 20 mm, and the area of ​​the information covering film 5b is approximately 89% of the area of ​​the antenna outer dimension region S of the antenna 13. Since the RFID tag 1b of Example 3 is the same as that of Example 1 except for the information covering film 5a, detailed description will be omitted.

[0029] The RFID tag 1c of Example 4 is provided with an antenna 13a having a different shape from those of Examples 1 to 3, as shown in FIG. 4(C). The antenna 13a of Example 4 has a larger outer dimension (width W×length T) than those of Examples 1 to 3, and the area of ​​the antenna outer dimension region S of Example 4 is larger than those of Examples 1 to 3. The information covering film 5 of Example 4 has the same size as that of Example 1, and is slightly smaller than the inlay base material 12 of the RFID inlay 2 and larger than the antenna 13a. In Example 4, the information covering film 5 covers the information writing section 17 of the protective film 4 and is arranged so as to overlap the entire antenna 13a and the entire IC chip 14. Here, in the configuration of Example 4, the outer dimension of the antenna 13a is about 94 mm (width W)×about 24 mm (length T) as shown in FIG. 6(B). Since the outer dimensions of the information covering film 5 are approximately 96 mm × approximately 26 mm, the area of ​​the information covering film 5 is approximately 111% of the area of ​​the antenna outer dimension region S of the antenna 13a. Note that the RFID tag 1c of Example 4 is the same as that of Example 1 except for the antenna 13a, and therefore detailed description thereof will be omitted.

[0030] As shown in Fig. 4(D), the RFID tag 1d of Example 5 is provided with the same antenna 13a as in Example 4, and has the same information covering film 5a as in Example 2 attached thereto. The configuration of Example 5 is such that the information covering film 5a covers the information writing section 17 of the protective film 4, and is arranged so as to overlap the entire IC chip 14 and also overlap a part of the antenna 13a. Here, as shown in Fig. 6(B), the area of ​​the information covering film 5a is about 80% of the area of ​​the antenna outer dimension region S of the antenna 13a. The RFID tag 1d of Example 5 is the same as Example 4 except for the information covering film 5a.

[0031] As shown in Fig. 4(E), the RFID tag 1e of Example 6 is provided with the same antenna 13a as in Example 4, and has the same information covering film 5b as in Example 3 attached thereto. The configuration of Example 6 is such that the information covering film 5b covers the information writing section 17 of the protective film 4, and is arranged so as to overlap the entire IC chip 14 and a part of the antenna 13a. Here, as shown in Fig. 6(B), the area of ​​the information covering film 5b is about 71% of the area of ​​the antenna outer dimension region S of the antenna 13a. The RFID tag 1e of Example 6 is the same as Examples 4 and 5 except for the information covering film 5b.

[0032] On the other hand, as shown in FIG. 5(A), the RFID tag 51a of Comparative Example 1 includes an RFID inlay 2 having the same antenna 13 as in Examples 1 to 3, and an information covering film 55a that is slightly larger than the RFID inlay 2 (inlay base material 12) and the protective film 4 is attached. The information covering film 55a is attached to cover the protective film 4 so as to protrude outward over the entire periphery of the protective film 4. As a result, in the configuration of Comparative Example 1, the information covering film 55a overlaps the entire RFID inlay 2. Here, the configuration of Comparative Example 1 includes an RFID inlay 2 having the same antenna 13 as in Example 1, and also includes the same protective film 4 as in Example 1. As shown in FIG. 6(A), the outer dimensions of the information covering film 55a are about 100 mm (horizontal dimension)×about 30 mm (vertical dimension), and the area of ​​the information covering film 55a is about 167% of the area of ​​the antenna outer dimension region S of the antenna 13. The RFID tag 51a of Comparative Example 1 is the same as that of Example 1 except for the outer dimensions of the information covering film 55a, and therefore a detailed description thereof will be omitted.

[0033] The RFID tag 51b of Comparative Example 2 includes the same antenna 13 as that of Comparative Example 1, and includes an information covering film 55b with a larger outer dimension than that of Comparative Example 1, as shown in FIG. 5(B). This information covering film 55b is larger than the RFID inlay 2 (inlay base material 12) and the protective film 4, and is attached so as to protrude outward over the entire periphery of the protective film 4. Here, as shown in FIG. 6(A), the configuration of Comparative Example 2 is such that the outer dimensions of the information covering film 55b are approximately 120 mm (horizontal dimension)×approximately 50 mm (vertical dimension), and the area of ​​the information covering film 55b is approximately 333% of the area of ​​the antenna outer dimension region S of the antenna 13. The RFID tag 51b of Comparative Example 2 is the same as that of Comparative Example 1, except for the outer dimensions of the information covering film 55b.

[0034] As shown in FIG. 5(C), the RFID tag 51c of Comparative Example 3 includes an RFID inlay 2 having the same antenna 13a as in Examples 4 to 6, and includes an information covering film 55b having the same outer dimensions as in Comparative Example 2. Similarly to Comparative Example 2, the information covering film 55b is attached so as to protrude outward over the entire periphery of the protective film 4. Here, in the configuration of Comparative Example 3, as shown in FIG. 6(B), the area of ​​the information covering film 55b is about 266% of the area of ​​the antenna outer dimension region S of the antenna 13a. The RFID tag 51c of Comparative Example 3 is the same as in Example 4 except for the outer dimensions of the information covering film 55b.

[0035] Although not shown, the RFID tag of Comparative Example 4 includes the same antenna 13a as Comparative Example 3, and includes an information covering film with a larger outer dimension than Comparative Example 3. The information covering film of Comparative Example 4 is attached so as to protrude outward over the entire periphery of the protective film 4, as in Comparative Example 3. Here, as shown in FIG. 6(B), the configuration of Comparative Example 4 is such that the outer dimensions of the information covering film are approximately 120 mm (horizontal dimension)×approximately 80 mm (vertical dimension), and the area of ​​the information covering film is approximately 426% of the area of ​​the antenna outer dimension region S of the antenna 13a. The RFID tag of Comparative Example 4 is the same as Comparative Example 3, except for the outer dimensions of the information covering film.

[0036] Furthermore, the configurations of Reference Examples 1 and 2, in which no information covering film was attached, were also evaluated for communication performance as a comparison target for the performance of Examples 1 to 6. The configuration of Reference Example 1 includes an RFID inlay 2 having the same antenna 13 as in Examples 1 to 3, and a protective film 4, but does not include an information covering film, while the configuration of Reference Example 2 includes an RFID inlay 2 having the same antenna 13a as in Examples 4 to 6, and a protective film 4, but does not include an information covering film.

[0037] FIG. 6 shows the results of an evaluation test of communication performance for the above-mentioned Examples 1 to 6, Comparative Examples 1 to 4, and Reference Examples 1 and 2. Here, the evaluation of communication performance was performed by measuring the communication distance in the 920 MHz band used in Japan. FIG. 6(A) shows the measurement results of the communication distance for a configuration having the same antenna 13 as Example 1. The RFID tags 1, 1a, and 1b of Examples 1 to 3 have a shorter communication distance than Reference Example 1 (not equipped with an information covering film), but the communication distance is longer than Comparative Examples 1 and 2. In this way, the configurations of Examples 1 to 3 can suppress the reduction in communication distance compared to Comparative Examples 1 and 2. In other words, the configurations of Examples 1 to 3 have improved communication performance compared to Comparative Examples 1 and 2.

[0038] On the other hand, Fig. 6(B) shows the measurement results of the communication distance for a configuration having the same antenna 13a as in Example 4. The RFID tags 1c to 1e of Examples 4 to 6 have a shorter communication distance than Reference Example 2 (no information covering film mounted), but the communication distance is longer than Comparative Examples 3 and 4. In this way, the configurations of Examples 4 to 6 can suppress the reduction in communication distance compared to Comparative Examples 3 and 4. In other words, the configurations of Examples 4 to 6 have improved communication performance compared to Comparative Examples 3 and 4.

[0039] In this way, in the RFID tag 1 of the present embodiment shown in Examples 1 to 6, the information covering film 5 is equal to or smaller in size than the protective film 4, and is formed with an area ratio of 70 to 140% to the area of ​​the antenna outer dimensional region S, and is attached without protruding outside the protective film 4. With this configuration, it is possible to suppress the deterioration of communication performance compared to the conventional configuration (corresponding to Comparative Examples 1 to 4) in which an information covering film larger than the protective film 4 is attached.

[0040] In the configuration of the embodiment, the information covering film 5 does not protrude outward from the protective film 4, so the information covering film 5 is less likely to become a peeling starting point, and the RFID tag 1 of the embodiment is less likely to peel off from the adherend to which it is attached. In the configuration of the comparative example 1 (FIG. 5(A)), the information covering film 55a is affixed protruding slightly outward from the protective film 4, so the adhesive width between the information covering film 55 and the adherend is short, and the information covering film 55 is more likely to peel off from the adherend and become a peeling starting point. In this way, the configuration of the embodiment is less likely to peel off from the adherend than the configuration of the comparative example 1.

[0041] This information covering film 5 covers the information writing section 17 of the protective film 4, and therefore can protect the information in the information writing section 17. In this embodiment, the information covering film 5 occupies 70% or more of the area of ​​the antenna outer dimensional area S, and therefore can protect the information writing section 17, in which a sufficient amount of information can be written.

[0042] Furthermore, in the configuration of this embodiment, the information covering film 5 is attached so as to overlap the IC chip 14 and the antennas 13, 13a, thereby protecting the IC chip 14 and the antennas 13, 13a. In particular, the information covering film 5 is attached so as to overlap the entire IC chip 14, thereby providing stable protection for the IC chip 14. This makes it possible to prevent damage to the IC chip 14, and allows communication to be performed for a relatively long period of time.

[0043] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present invention. For example, the antenna of the RFID inlay is not limited to the shapes of the first to sixth embodiments, and other shapes may be used, and the same effects as those of the embodiments may be achieved. Specifically, the antenna may be a thin antenna wire that is provided in a meandering shape in the longitudinal direction.

[0044] In addition, the position where the information covering film is attached to the surface of the protective film is not limited to the above-mentioned embodiment, and can be changed as appropriate. For example, Fig. 7 shows a configuration in which an information covering film 5b (same configuration as in Example 3) having a size of about 89% of the area ratio of the antenna outer dimension region S is attached to a different position of the protective film 4. In the RFID tags 1f and 1g of the other examples, the information covering film 5 is attached to the surface of the protective film 4 so as to protect the entire area of ​​the information writing section 17, overlap the entire IC chip 14, and overlap a part of the antenna 13. Even with the configuration of such another example, the same action and effect as in Example 3 can be achieved.

[0045] In the embodiment, the RFID inlay 2 is provided with an antenna 13 and an IC chip 14 on the surface of the inlay substrate 12, and the protective film 4 is attached to the RFID inlay 2, but the present invention is not limited to this, and the inlay substrate may be formed of a protective film. Specifically, the RFID inlay is provided with an antenna and an IC chip on the back surface of an inlay substrate made of white PET, and an adhesive layer is provided on the back surface of the RFID inlay, and the RFID inlay is removably attached to a release paper via the adhesive layer. An information writing section is provided on the surface of the inlay substrate, and an information covering film is attached to the surface of the inlay substrate. In this configuration, the inlay substrate has the function of a protective film. Even in this configuration, the same effects as those of the above-mentioned embodiment can be achieved by providing an information covering film in the same manner as in the above-mentioned embodiment. [Explanation of symbols]

[0046] 1,1a~1g RFID tags 2. RFID inlay 4 Protective film 5,5a,5b Information Covering Film 13 Antenna 14 IC chip 17 Information entry section T Vertical width (outer dimensions) W Width (outer dimensions)

Claims

1. An IC chip; an antenna connected to the IC chip; a protective film that covers the IC chip and the antenna and has an information writing section on a surface of which required information is written; and an adhesive layer is provided on the back surface of the RFID tag to be attached to an object to which the RFID tag is attached, The RFID tag is characterized in that it is provided with an information covering film which is formed to be the same size as or smaller than the protective film, covers the information entry section, overlaps the IC chip and the antenna, and is attached to the surface of the protective film without protruding outward.

2. Information covering film is 2. The RFID tag according to claim 1, wherein the area of ​​the RFID tag is 70 to 140% of the outer area of ​​the antenna defined by the outer dimensions of the antenna.

3. Information covering film is 3. The RFID tag according to claim 1, wherein the RFID tag is attached to a surface of a protective film so as to overlap the entire IC chip and at least a part of the antenna.

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