JP4743434B2 - Non-contact IC tag - Google Patents

Description

  The present invention relates to a non-contact IC tag. Specifically, a flat antenna element is formed on both sides centered on the IC chip on the base film, and a non-contact IC chip with a diversity function that can select either antenna element according to the reception strength of the antenna is mounted. Regarding IC tags, by cutting the planar antenna element from the planned cutting line close to the IC chip together with the base film, it functions as a tag having a large size and a long communication distance before cutting, and the size is the same frequency after cutting. The present invention also relates to a non-contact IC tag that functions as a small tag having a short communication distance.

  The non-contact IC tag is also referred to as an RFID (Radio Frequency Identification), and relates to a tag that includes an IC chip that holds information capable of identifying an individual and can read this information by wireless communication in a non-contact manner. Such IC tags are used in fields such as transportation and distribution, warehouses, factory process management, and handling of luggage.

In recent years, in addition to the conventional 13.56 MHz band or microwave band (2.45 GHz) non-contact IC tag, it has become possible to use the UHF band (952 M to 955 MHz) in Japan due to the revision of the law. Band non-contact IC tags are being put to practical use.
The UHF band IC tag can be collectively read from a long distance (3 to 5 meters) as compared to the electromagnetic induction type 13.56 MHz band non-contact IC tag. Further, the microwave band IC tag can communicate at a distance of 1 to 1.5 meters, and is expected to be widely used in applications that take advantage of these features in the future.
In the classification of radio waves, the UHF band indicates 300 M to 3 GHz, but in the case of a non-contact IC tag, it often refers to a tag using 860 M to 960 MHz. An IC tag that uses the 2.45 GHz band included in the above range is called a microwave band, and is not usually a UHF band IC tag.

  The frequency band in Japan that can use the UHF band IC tag can use 2 MHz of 952 M to 954 MHz for the high output type and 3 MHz of 952 M to 955 MHz for the low output type by amendment of the Radio Law in April 2005. The UHF band IC tag had problems such as the weak response wave of the IC tag being interfered by the transmission wave of other reader / writers, and it was pointed out that it was difficult to read. This prevents this interference.

By the way, as a method of using the non-contact IC tag label, there are cases where it is necessary to cut the size into two and use it. In this case, substantially the same function is required before and after cutting.
An example will be described with reference to FIG. For example, in the case of men's shoes and women's shoes, after work such as inspection of delivered products, for good products, the product number, size, color pattern, price, etc. are written on the original size product label 22 and stored in a shoe box 21 containing shoes. The described product label 22 is attached (FIG. 15A). The product label has a shape such as a horizontally long shape, and includes a portion 22a which is left attached to the shoe box and a portion 22b which is cut from the perforation line 5 and suspended on the shoe. A substantially similar content is printed on both parts by a printer and attached to the shoe box 21. When displaying shoes at a storefront, the hanging portion 22b is cut out and attached to the shoe 20 (FIG. 15C), and the shoebox is attached to the predetermined portion with the remaining portion 22a attached for inventory confirmation. Are accumulated and stored (FIG. 15B). At the store, the contents can be confirmed by the hanging portion 22.

  The above is an example of using a conventional product label, but if the product label has a non-contact IC tag (usually a film-like non-contact IC tag is often inserted inside the label paper base). It is also useful for finding shoes in a boxed state. UHF band IC tags can be scanned and inspected differently from shoes when delivering shoes. Also, if the hanging portion 22b side after being cut into two also has an IC tag function, it is convenient for examining the contents of the shoes on the display shelf, and in order to clarify the correspondence between the shoes 20 and the shoe box 21 Also useful. It functions as a tag with a long communication distance for searching for a shoe box in a boxed state, and functions as a tag with a small size and a short communication distance when searching for a hanging part of a shoe at a store. For this purpose, an IC tag in the UHF band or microwave band that can be used for remote read / write is particularly advantageous.

Generally, when a plurality of IC tags are collectively read using a gate or the like at the time of delivery of goods, it is preferable that the communication distance of the tags is long to some extent (several meters). For this reason, the gain of the antenna should be as large as possible, and it is desirable that the area that the antenna can occupy be large.
However, when one IC tag is attached to each product at a retail store or the like, a great communication distance is not required. For example, it is assumed that the IC tag is used by being attached to a price tag, and the tag antenna is desirably as small as possible. In that case, it is sufficient to read from a distance of about several centimeters using a handy type reader. However, the handy type reader has a very small radio wave output compared to a stationary type reader due to its size and battery capacity constraints, and the communication distance is small. Short is common. Therefore, it is desirable that the gain of the tag antenna does not decrease as much as possible even when it is downsized. Of course, when using a stationary reader with a large output instead of the handy type, it is obvious that reading is possible even if the tag antenna gain value is lower than when using the handy type.

That is, if the gain and size are arbitrarily changed depending on the scene in which the IC tag is used, and the contents of the connected storage circuit can be maintained as they are, the contactless IC tag is easy to use. As a specific example, before cutting, it mainly operates as a half-wave dipole antenna with a large communication distance, suitable for batch reading at the gate, and after cutting, it operates as a small half-wave dipole antenna with a small communication distance, Alternatively, it is desired to realize an IC tag that is incorporated inside (paper layer) and is suitable for reading with a handy reader.
For the same purpose, the applicant has previously filed a patent application listed in Patent Document 4, and has proposed a non-contact IC tag that responds to the same frequency before and after cutting from the planned cutting line.

  Incidentally, in recent years, IC chips having a diversity function have been supplied. The diversity function means that a switching mechanism for the antenna is built in the chip, and has a function (circuit) that determines the strength of the input power of the two antennas and automatically selects the stronger one. The diversity function is generally used for mobile phone devices, in-vehicle antennas, various mobile communication terminals, and the like. Here, the antenna design of the IC tag when the diversity function is used and when it is not used will be described with reference to FIG.

FIG. 14A illustrates an IC tag antenna that uses a diversity function, and FIG. 14B illustrates an IC tag antenna that does not use a diversity function. The latter is a content related to the proposal of Patent Document 4. The central square shape means an IC chip.
The IC chip 3d in FIG. 14A has a diversity function and has two or more antenna input terminals, the minus side is connected to the antenna 1 and the antenna 2, and the plus side is connected to the antenna 1 and the antenna 2 by a switch mechanism. Switchable. In the case of FIG. 14B, a normal two-terminal IC chip 3n having no diversity function is used, and the antenna 1 and the antenna 2 are connected to the two terminals.

  As shown in FIG. 14B, when the IC chip 3n having no switching mechanism is used (when the diversity function is not used), the antenna 1 having a large size and a long communication distance is mainly used in the state before the cutting from the planned cutting line 5. Although it operates, the antenna 2 that is small and has a short communication distance remains connected. Therefore, it is necessary to design the antenna in consideration of the effect of the antenna 2 being connected. For this reason, there exists a problem which becomes difficult to design. As shown in FIG. 14A, when the IC chip 3d having a switch mechanism is used (when the diversity function is used), either the antenna 1 or the antenna 2 is used while the other is cut off even in the state before the disconnection. Therefore, since the characteristics close to those of two independent antennas are shown, there is an advantage that the antenna design becomes easy.

As prior arts related to the present application, there are Patent Documents 1 to 3. Patent Document 1 describes that an antenna is cut when a label is cut with respect to a wireless tag of 900 MHz band or the like. However, since the wireless tag of the same document cuts both ends of the dipole antenna, there is a problem that the resonance frequency changes between the original wireless tag and the wireless tag after cutting. If the resonance frequency changes, there arises a problem that two types of reader / writers must be used.
Patent Document 2 and Patent Document 3 describe an antenna device and the like that are switched and used by a diversity operation.

JP 2006-203637 A JP 2001-298385 A JP 2004-260563 A Japanese Patent Application No. 2006-321061

Using an IC chip having a diversity function, the strength of the input signals of the two antennas is determined, and the stronger one is automatically selected. Accordingly, an object of the present invention is to realize an IC tag that secures the best communication state even in an IC tag that is not cut.
A non-contact IC tag that is used by cutting an IC tag. The non-contact IC tag has a large communication distance before cutting and can communicate over a relatively small communication distance after cutting, and can read and write with radio waves of the same frequency before and after cutting. It aims at realization.

The non-contact IC tag of the present invention operates with a relatively wide antenna area before cutting, suitable for batch reading at the gate, operates as a small half-wave dipole antenna after cutting, and is handy for use as a price tag Achieving an IC tag suitable for reading with a reader.
Another object of the present invention is to incorporate a short circuit that prevents the antenna on the other side from resonating while the antenna on one side is operating in the IC tag before cutting.

Abstract of the invention for solving the above-mentioned problems, the two or more antenna input terminal of the IC chip having a diversity feature involves two dipole planar antenna resonates with a radio wave of the same predetermined frequency in the UHF band or microwave band elements are connected, the IC chip, a non-contact IC tag that is adapted to select the large end of the reception intensity of any of the dipole planar antenna element, in a position close to the IC chip , There is provided a predetermined cutting line for cutting one of the two dipole planar antenna elements, and the function of the dipole planar antenna element on the side where the IC chip does not remain after cutting from the planned cutting line is provided. are so as to lose, after cleavage by the cutting line, the dipole planar antenna element side where the IC chip does not remain Is is, the non-contact IC tag in which the IC chip is characterized in that the larger size of the dipole planar antenna element side remaining, in.

  In the above, the short circuit is such that a part of the other dipole type planar antenna element is short-circuited to the one dipole type planar antenna element so that the other antenna element does not resonate when one antenna element is operating. Is provided, it is possible to prevent resonance and improve the antenna characteristics before cutting. Moreover, it is preferable that the said short circuit is invalidated after a cutting | disconnection.

  In the above, if the paper base material is laminated on the outer surface of the base film so that it can be printed by a printer, the product management matters that are at least partially in common with the content recorded in the memory of the IC chip are printed on the paper base material. it can. Further, if the planned cutting line is formed so as to penetrate the paper base material and the base film, the cutting can be facilitated even when the label for printing recording is used. Further, the printable surface of the paper base on both sides of the planned cutting line may be printed with merchandise management items that are at least partially in common with the contents recorded in the memory of the IC chip. , There will be no mistakes in the recorded contents.

The contactless IC tag of the present invention (Claim 1) uses an IC chip having a diversity function, and resonates with radio waves of the same frequency in the UHF band or the microwave band on both sides thereof, and has different directivity characteristics. Since two dipole antennas are formed, one of the two dipole planar antenna elements is selected according to the reception intensity, so that the best communication state can always be ensured.
Since the non-contact IC tag of the present invention (Claim 1 ) is provided with a planned cutting line on the IC tag , after cutting from the planned cutting line, only the antenna side with a relatively short communication distance operates, and the proximity distance Therefore, the IC tag is easy to read and write.

In the non-contact IC tag of the present invention (Claim 1 ), two planar antenna elements are connected to an IC chip having a diversity function through a planned cutting line, but the IC chip receives signals from two antennas. Since the strength is judged automatically and the stronger one is automatically selected, the best communication state can always be secured even before disconnection, and only the antenna side with a relatively short communication distance operates after disconnection, The IC tag is easy to read / write from a close distance.

Since the non-contact IC tag of the present invention (Claim 2 ) is provided with a short circuit so that one antenna element does not resonate while the other antenna element is in operation, A good communication state can be secured when used.

When the paper base material is laminated so that the non-contact IC tag of the present invention can be printed on the outer surface of the base film (Claim 4 ), the commodity management matters common to the IC chip recording contents are provided on the paper base material. Recording is possible. Further, if there is a planned cutting line, the planned cutting line can be formed so as to penetrate the paper base material and the base film together (Claim 4 ), and the IC chip recording contents are formed on the paper base material on both sides thereof. Commodity management items can be recorded, and even after the non-contact IC tag is cut, the correspondence between the two can be easily searched (Claims 4 and 5 ).

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a diagram showing an example of a planar antenna element of a non-contact IC tag, FIG. 2 is a detailed structural diagram of an IC chip mounting portion, and FIG. 3 is a diagram in which a non-contact IC tag of FIG. 4 is a diagram illustrating the directivity of the non-contact IC tag before cutting, FIG. 5 is a diagram illustrating the directivity of the non-contact IC tag after cutting, and FIG. 6 is a diagram illustrating the difference in directivity, 7 is a two-dimensional diagram showing the directivity of the non-contact IC tag before cutting, FIG. 8 is a two-dimensional diagram showing the directivity of the non-contact IC tag after cutting, and FIG. 9 is a diagram of the IC tag before cutting. FIG. 10 is a diagram showing the antenna gain and return loss of the IC tag after cutting, FIG. 11 is a diagram showing another example of the planar antenna element of the non-contact IC tag, and FIG. FIG. 13 is a diagram showing the directivity characteristics of a reader / writer composed of a planar antenna, and FIG. 13 is a plan view of the non-contact IC tag of the present invention. External view, it is.

FIG. 1 is a diagram illustrating an example of a planar antenna element of a non-contact IC tag. As shown in FIG. 1, the planar antenna element 4 of the non-contact IC tag 1 of the present invention includes two antenna elements 41 and an antenna element 42, and each antenna element 41, 42 serves as an antenna input terminal of the IC chip 3. Connected. Both the antenna element 41 and the antenna element 42 are half-wavelength dipole antennas, but the left antenna element 41 has a slightly larger shape than the right side. The left and right antenna elements can be designed to have different sizes and directivity characteristics, and in that case, one of the antennas having a large signal input can be automatically selected and operated.
The antenna element 4 is formed on the surface of the base film 11, and the entire surface of the antenna element 4 and the IC chip 3 is covered with a surface protection sheet made of a plastic film.

  The IC chip 3 used for the IC tag 1 has a diversity function, and has two or more antenna input terminals. The diversity function performs switching by amplifying the received waves of the two planar antenna elements 41 and 42 connected to the input terminals, determining the strength thereof. The two amplifier circuits of the IC chip 3 are required to have the same electrical characteristics such as amplification characteristics and frequency characteristics in order to accurately perform the determination.

Lines (thick solid lines) 41a and 41b refracted to the left from the mounting portion of the IC chip 3 are portions that function as a dipole antenna 41 with a large communication distance, and the total length of the entire line is set to be approximately a half wavelength. ing. In the figure, a portion surrounded by a one-dot chain line operates as an IC tag in a large state, and a portion surrounded by a two-dot chain line operates as an IC tag in a small state. Although the right side is a folded dipole, the total length of the lines (thin solid lines) 42 a and 42 b including the line leading to the IC chip 3 is set to a substantially half wavelength. With the diversity function of the IC chip 3, the one-dot chain line portion and the two-dot chain line portion can be switched and connected.
In the case of FIG. 1, the IC chip 3 is mounted at a position slightly shifted from the center position of the planar antenna element 42. This avoids a portion that may be printed on the label surface, and there is no particular electrical reason.

In the half-wave dipole antenna, the shape of the half-wavelength current distribution of the irradiated radio wave is set. For example, when the UHF band is 954 MHz, one wavelength is 31.4 cm, and a half wavelength is 15.7 cm. When the condition is satisfied, resonance with radio waves is efficiently generated.
Usually, the base film 11 is designed to be about 160 mm in consideration of the dielectric constant of the base film 11 and the resistance value of the antenna. The size of the IC tag label is 10cm and the width is about 3cm to 5cm (base material size) so that the base material size of the label does not become too large. The In the case of the microwave band (2.45 GHz), the antenna has a shorter shape. In the case of a folded dipole, the total length of the line is in principle a length suitable for the wavelength. However, if the folding is too close, it is coupled in space, so a design ingenuity is required.

  The antenna element of FIG. 1 is devised to prevent resonance during the operation of the IC tag 1 in a large state. In FIG. 1, the circuits denoted by reference numerals 46, 47, and 48 form a short-circuit portion. However, if there is no short-circuit portion, the following problem occurs. That is, when the IC tag 1 in a large state is to be operated, if the small dipole antenna 42 that operates as an element in the IC tag 2 in the small state is in a state of resonating at a desired frequency, the operation as both antennas can be performed. Competing and overall gain decreases. Therefore, in the IC tag 1 in a large state, a part that operates as an element in the IC tag 2 in a small state is partially short-circuited to shift the resonance frequency. The short-circuit portions 46, 47, and 48 are invalidated at the same time that the IC tag is disconnected from the planned cutting line 5, and the small-sized IC tag operates as an original small half-wave dipole antenna 42. .

  Providing the short-circuit portion also has the following secondary effects. A semiconductor such as an IC chip generally has a risk of being destroyed when a high voltage is applied due to static electricity. Static electricity is easily generated both in the manufacturing process and in actual use. For this reason, there are many cases in which a high voltage protection mechanism is built in the semiconductor, but in reality, it is not completely destroyed by static electricity. In the large tag 1, reference numerals 41 a and 41 b are connected to terminals of the IC chip 3 (reference numerals 31 and 32 in FIG. 2), but by providing a short-circuit portion, 41 b -short-circuit portion 48-42 a- 42b-short circuit portion 46-41a is shorted between 41b-41a, and even if a high voltage is generated between 41a-41b, it is discharged through the above-mentioned route and a high voltage is applied between IC chip terminals 31 and 32. This contributes to reducing the risk of breakdown due to static electricity. By considering this structure in advance when designing the antenna, it is possible to prevent the transmission / reception ability from being impaired.

FIG. 2 is a detailed structural diagram of the IC chip mounting portion. In FIG. 2A, the IC chip 3 is transparently shown for easy understanding of the circuit state. As shown in FIG. 2B, the IC chip 3 has three input terminals, the left half-wave dipole antenna 41 is connected to the ground terminal 31 and the antenna terminal 32, and the right half-wave dipole antenna 42 is The ground terminal 31 and the antenna terminal 33 are connected. The ground terminal 31 is common to the left and right antennas.
In FIG. 2B, since the switch mechanism 34 of the IC chip 3 connects the terminals 31 and 32, the left half-wave dipole antenna 41 is in an operating state.

  FIG. 3 is a diagram in which a scheduled cutting line 5 is provided in the non-contact IC tag of FIG. FIG. 3A shows a non-contact IC tag before cutting, and FIG. 3B shows a non-contact IC tag after cutting. As described above, the antenna element 41 and the antenna element 42 can be designed to have different directivity characteristics. However, before cutting in FIG. 3A, the directivity characteristics are the same in a normal non-contact IC tag reading state. The input signal of the left antenna element 41 having a large antenna shape becomes large. Therefore, in the normal case before cutting, the left antenna element 41 surrounded by the alternate long and short dash line operates (see FIG. 1). Of course, in the small size non-contact IC tag 2 cut from the planned cutting line 5, the right antenna Only element 42 operates. The function of the dipole planar antenna element 41 on the side where no IC chip remains is lost.

  The planned cutting line 5 at a fixed position is because if it is cut at an arbitrary position, it may not function sufficiently as an antenna of the IC tag after cutting, and it is necessary to cut from the designed predetermined position. is there. Accordingly, the planned cutting line 5 is previously formed by a perforation line or the like so as to be easily cut. The planned cutting line 5 is provided at a position close to the IC chip 3. The close position is a position of about 1 mm to 10 mm from the left end of the antenna element 42 close to the IC chip 3.

  In a large size state before cutting of the non-contact IC tag 1, either the antenna element 41 or the antenna element 42 is selected and operated. Usually, the large-size antenna element 41 is selected and used as a half-wave dipole antenna. Work. In the small size state after cutting, only the half-wavelength dipole antenna 42 functions. Both are designed to resonate with radio waves of the same predetermined frequency in the UHF band or microwave band. In general, the communication distance is long when the size is large, and the communication distance is shortened when the size is small.

  The conductor of the antenna 4 is a printed pattern or an etching pattern of a metal foil, like a normal non-contact IC tag. Generally, pattern printing is performed using a printing resist on a base material in which a metal foil (aluminum foil or copper foil having a thickness of about 10 μm to 20 μm) is laminated on a plastic film, or the surface coated with a photosensitive resist is exposed through a photomask. In many cases, the metal foil is then etched through a resist film. If the metal foil has a thickness in the above range, the resistance value of the antenna line is appropriate. In the case of a printed pattern or a metal deposition layer, the resistance value is often too high.

The non-contact IC tag 1 (before cutting) and the small non-contact IC tag 2 (after cutting) of the present invention are prepared so that the impedance of the antenna and the impedance of the IC chip 3 can be matched. The antenna impedance matching (matching) is performed by the shape of the antenna pattern or a combination of a dielectric or magnetic material as a base material. In the present invention, matching is performed by the antenna pattern shape. Specifically, matching is performed by a hairpin match circuit (circuit for converting impedance to a complex number) 43 or the like.
Block-like patterns 44 and 45 at the tip of the left antenna element 41 are also used for impedance adjustment. If the impedances do not match, there is a problem that radio waves are reflected by the power feeding unit.

  FIG. 4 is a diagram showing the directivity characteristics of the non-contact IC tag before cutting, and FIG. 5 is a diagram showing the directivity characteristics of the non-contact IC tag after cutting. The coordinate axis (A) and the three-dimensional Directivity (B) is shown. In a large state of the IC tag before cutting, as shown in FIG. 3B, the communication distance is large and the donut-shaped directivity characteristic having the Y axis as the axis is shown. On the other hand, in the small state of the IC tag after cutting, as shown in FIG. 5B, the communication distance is small and the donut-shaped directivity characteristic with the X axis as the axis is shown.

  The reason why the directivity difference occurs will be described with reference to FIG. In the IC tag 1 in a large state, the left antenna element 41 operates as shown in FIG. 6A. However, since the element arrangement is substantially similar to the dipole antenna arranged in the long side direction, its directivity is Is close to a dipole antenna whose electric field surface is aligned in the long side direction. On the other hand, the IC tag 2 in a small state is a dipole antenna arranged so as to extend in the short side direction as shown in FIG. 6B, and its directivity is that of a dipole antenna whose electric field surface is aligned in the short side direction. It will be close. In general, the electric field plane coincides with the direction of the dipole antenna, and the magnetic field plane is orthogonal to the electric field plane.

In general, the antenna directivity is considered to be viewed from infinity. Therefore, the size of the IC tag itself is not present (handled as a point). The large tag emits radio waves from the left antenna, but the coordinate origin is not displayed separately.
7 and 8 are two-dimensional diagrams showing the directivity of the non-contact IC tag before and after cutting. The non-contact IC tag 1 before cutting in FIG. 7 has a circular gain on the XZ plane and a gain of “8” on the YZ plane. Both maximum gains are close to 0 dB. In the non-contact IC tag 2 after cutting in FIG. 8, the XZ plane shows a “8” -shaped gain, and the YZ plane shows a circular gain. Both antenna maximum gains are close to -4 dB.

  FIG. 9 is a diagram showing the antenna gain (A) and return loss (B) of the IC tag before cutting, and FIG. 10 is a diagram showing the antenna gain (A) and return loss (B) after cutting similarly. It is. It is a calculated value (simulation calculation result by the finite element method) about the antenna of FIG. In either case, the antenna gain is maximized near 950 MHz, and the return loss is minimized. The above is to adjust the characteristics to the UHF band of Japan, but it is obvious that the characteristics can be adjusted to the microwave band and the frequency band of other countries.

The antenna gain represents the ability of the antenna to receive radio waves coming from a desired direction, and it can be said that the larger the value, the better the characteristic, except for special applications. It is common to design for maximum at the desired frequency. When an isotropic antenna is used as a reference antenna, an absolute gain (dBi) is assumed, and when a dipole antenna is used as a relative gain (dBd), there is a relationship of (absolute gain) = (relative gain) +2.15 dB. .
Return loss is an index of electrical matching between the antenna and the IC tag chip, and the lower the value, the better the characteristic. Expressed as a ratio of the incident power to the antenna and the reflected power at the contact point, 0 dB is shown when all the power is returned by total reflection, and -∞ dB is shown when the power is not returned. Therefore, it is common to design to be the lowest at the desired frequency.
The return loss is a parameter that also affects the antenna gain, and the peak of the antenna gain and the peak of the return loss generally coincide with each other. In the case of FIG. 9 and FIG. 10, the IC tag 1 in the large size state and the IC tag 2 in the small size state have almost the same antenna gain peak and return loss peak, and resonate at the same frequency even if the size changes. I understand that.

FIG. 11 is a diagram illustrating another example of the planar antenna element of the non-contact IC tag. Also in the example of FIG. 11, it can be used as the small size non-contact IC tag 2 by cutting from the planned cutting line 5.
In the state of a large size before cutting in FIG. 11A, the half-wave dipole antenna 41 mainly operates, and in the state of small size after cutting in FIG. 11B, the half-wave dipole antenna 42 operates. The IC chip 3 has a diversity function, and is attached to three terminals as in the case of FIG. The overall length (linear distance) of the planar antenna element 4 can also be within 100 mm, and the width can be about 30 to 40 mm. Other configurations are the same as those of the non-contact IC tag 1 of FIG.

FIG. 12 is a diagram showing the directivity characteristics of a reader / writer composed of a planar antenna. It is composed of a single-element planar antenna, and as shown in FIG. 12A, the directivity is enhanced with respect to the Z-axis direction orthogonal to the planar antenna. As shown in FIG. 12B, a long communication distance can be obtained by making the Z-axis direction coincide with the IC tag direction.
Although the directivity of the reader antenna is calculated with linearly polarized waves, the directivity is almost the same with circularly polarized waves.

There are circularly polarized antennas and linearly polarized antennas for reader / writers. The case of using in combination with a tag using a dipole antenna which is the most general linearly polarized antenna will be described below. This is not limited to an IC tag, but can be regarded as a general theory about the relationship between circularly polarized waves and linearly polarized waves.
-When a linearly polarized wave is used for the reader antenna, a loss may occur due to the posture of the tag and the communication distance may be reduced. This loss increases / decreases depending on the angle of the tag orientation and the direction of polarization (electric field plane direction). The loss is minimized when the angle is 0 degree, and the loss is maximized when they are orthogonal to each other (theoretical). To infinity). Therefore, it is necessary to use the tag with the polarization direction matched as much as possible.
-If a circularly polarized wave is used for the reader antenna, fluctuations in loss can be reduced depending on the posture of the tag. In principle, there is no difference in loss, that is, no difference in communication distance when the tag is placed horizontally and vertically. However, a demerit in this case is a reduction in the maximum communication distance. When a circularly polarized reader antenna is used, a loss of 3 dB is generated in principle, and the maximum communication distance is about 70% compared to when a linearly polarized reader antenna is used.

  In actual IC tag operation, the tag orientation cannot be specified in many cases, and thus a circularly polarized reader antenna is often used to increase the reading rate. However, since the electric field strength at the position of the IC tag changes in a complex manner due to surrounding radio wave reflectors, there are aspects that are generally not good either. In some cases, it is better to use a linearly polarized antenna. There is also a possibility that

  Since the actual non-contact IC tag 1 is provided with printability so that the antenna surface is covered with label paper or the like, the antenna line is normally made invisible. In general, a paper label on which a product name, a manufacturer, a product price, and the like are printed is first manufactured as a brand tag. Next, a non-contact IC tag label on which data has been recorded is attached to the half of the brand tag using a label attaching machine using a product tag issuing machine. After that, the brand tag is folded in half with the IC tag inside. In some cases, the IC tag can be seen on one side without being folded in half. The non-contact IC tag 1 in such a state is also called a product tag, and has an advantage that both printing and bar code recording and electronic recording on the IC chip 3 are possible. These details are also described in the applicant's earlier application (Japanese Patent Application No. 2005-195785 and the like), and can be finished into a final product by the manufacturing method.

  FIG. 13 is an external view of a non-contact IC tag according to the present invention. FIG. 13A is a plan view of the entire size. Since the non-contact IC tag 1 is covered with a paper label, the antenna 4 of the IC tag cannot actually be seen from the outer surface. The planned cutting line 5 at a certain position is formed by a perforation line or the like so as to penetrate the base film 11 of the IC tag, the surface protection sheet, and the paper label together. The planned cutting line 5 is usually formed so as to divide the entire non-contact IC tag 1, and one side thereof has a relatively large area, and the other side is often formed in a slightly small area. On the paper label surfaces on both sides of the non-contact IC tag 1 via the planned cutting line 5, product management items 8 that are at least partially in common with the contents recorded in the memory of the IC chip 3 are printed. The product management item 8 is a product name, manufacturer name, size, shape, price, or the like.

The total length (linear distance) L1 (see FIG. 1) of the antenna 4 of the non-contact IC tag 1 is set within about 100 mm. If the total length is large, the antenna design becomes easy, but EPC Global stipulates that the antenna design should be within 4 inches. The width L2 of the antenna 2 is about 30 mm to 40 mm by design, but the total length L and width H of the label itself can be freely determined depending on the purpose of use, the base material to be used, and the paper label to be laminated.
FIG. 13B is a diagram of the non-contact IC tag 2 after cutting. The IC chip 3 mounted on the antenna element 42 is provided on the surface of the base film 11, and a paper label base material is laminated on one surface or both surfaces thereof. It can also be attached to a product or the like by a string or the like passed through the string passage hole 9.

  When data is continuously written at the start of use of the non-contact IC tag 1, the IC tag connecting body is intermittently sent while being placed in the proximity of the low output reader / writer (distance of 1 to 3 cm). Write so that radio waves reach only the IC tag 1. Other than the IC tag 1 to be written may be shielded for writing. When pasting on a brand tag with a labeling machine, data is written immediately before pasting. Matching with the data to be printed on the brand tag is achieved, so that different data is not written. Note that writing means that data used mainly for writing is received from the reader / writer and written to the memory of the IC chip 3, and it is natural that the data (for example, the unique ID) of the IC chip 3 can be read. It is.

As described above, the frequency band in Japan where UHF band IC tags can be used is 2 MHz from 952 M to 954 MHz for the high output type, and 3 MHz from 952 M to 955 MHz for the low output type. As the UHF band IC tag reader / writer, there is “XR480-JP” of Symbol Technologies as an installation type. These antennas are quite large.
As a low output handy reader / writer, “BHT-230QWID” (952 M to 955 MHz; output 10 mW) will be released soon from Denso Wave Co., Ltd. The reading distance is seen to be about 10 cm. As another low output type UHF band IC tag, a reader / writer of Fujitsu Limited can be used. For example, a CF type reader / writer “TFU-RW526” for accessing the UHF band RFID tag can be used by inserting the Multipad main body “FHT401SS1” into the main body. In this case, the communication distance is about 3 cm to 10 cm.

  The non-contact IC tag 1 can be manufactured by the same process as that for manufacturing a conventional non-contact IC tag. As the base film 11, a material obtained by laminating a metal foil (for example, aluminum or copper foil) on the base film surface is used. A photosensitive photoresist is applied to the metal foil surface of the base film 11 and exposed to light using a photomask to form a resist layer. The photomask has an antenna pattern having the above-described configuration. A method of printing a resist pattern without using a photomask may be used.

Next, the metal layer is etched to form a predetermined pattern. After etching, the IC chip 3 is mounted on the dipole antenna 2 of the base film 11 with an anisotropic conductive adhesive film or the like, and then a surface protective sheet is laminated, and the back surface of the base film is processed with an adhesive.
As the IC chip 3, a UHF band or microwave band compatible IC chip is used. For example, there is a US company Impinge “Monza” which uses a diversity function.
It is necessary to form the planned cutting line 5 by numerically controlling the perforation line while detecting the antenna line so that the antenna line is not cut after the paper brand tag is attached to the front surface or front and back surfaces. Become.

A non-contact IC tag having a design frequency of 953 MHz was prototyped based on the antenna pattern of FIG. An aluminum foil having a thickness of 12 μm was laminated on a transparent biaxially stretched polyethylene terephthalate (PET) film having a thickness of 38 μm and used as the base film 11.
After that, an antenna pattern as shown in FIG. 1 was resist printed and etched. The full length (linear distance) L1 of the planar antenna element 4 is 87.5 mm, the width (linear distance) L2 is 26.0 mm, and the length (linear distance) L3 of the half-wave dipole antenna 42 is 29.5 mm. I did it. The short-circuit portions 46, 47, and 48 are also provided as shown in FIG. The line width of the thick line in the antenna element 41 portion was 1.0 mm, and the line width of the thin line in the antenna element 42 portion was 0.5 mm.

A non-contact tag IC chip [Impinge "Monza"] 3 having a diversity function is mounted on the chip mounting portion of the antenna 4 of FIG. The impedance of the IC chip 3 is 33 ± j112 (Ω). Thereafter, a transparent biaxially stretched PET film having a thickness of 20 μm is laminated on the surface of the IC chip 3 and the planar antenna element 4 as a surface protection sheet, and an adhesive (with release paper) is processed on the side surface opposite to the antenna 4 of the base film 11. went. Thereafter, label release was performed on the release paper surface so that the size of one antenna sheet with an IC tag was 35 mm × 95 mm.
Next, using a labeling machine with a reader / writer, the product management data is written on the IC chip 3 and the same product management data 8 is printed on both sides of the planned cutting line 5 on the brand tag (250 μm thick roll paper). Recorded.

  The brand tag on which the commodity management item 8 has been printed is folded in two on both sides of the antenna sheet and labeled. At that time, the release paper was removed. Thereby, the non-contact IC tag 1 of the present invention was completed. One completed non-contact IC tag 1 has a total length L of 100 mm and a width H of 40 mm. After labeling, care was taken not to damage the antenna line, and the planned cutting line 5 and the string through hole 9 were formed by the perforation line.

  The calculated values of the antenna gain and return loss of the IC tag before and after cutting of the non-contact IC tag 1 are as shown in FIGS. In the IC tag 1 in a large state, a flat characteristic is obtained in a gain range of 920 to 1000 MHz including 953 MHz. Moreover, the return loss in that range is −6 dB or less. In the IC tag 2 in the small state, the band is narrow, but the peak of the antenna gain and the return loss peak are both adjusted to approximately 953 MHz, and it can be seen that even if the size changes, the IC tag 2 resonates at 953 MHz.

  The completed non-contact IC tag 1 in a large state can be remotely read from a distance of 4 meters (using “XR480” -JP ”manufactured by Symbol Technologies) and is small after cutting from the planned cutting line 5 The non-contact IC tag 2 in the state could be a proximity lead (using “FHT401SS1” manufactured by Fujitsu Limited) from a distance of about 10 cm. In either case, the same common merchandise management items that were printed and recorded on the merchandise tag could be read.

  In the above-described embodiments, the UHF band (952 to 955 MHz) in Japan is described, but it is applicable to the UHF band (915 ± 14 MHz) in the United States and other UHF bands and microwave bands. It will be obvious to those skilled in the art.

It is a figure which shows the example of the planar antenna element of a non-contact IC tag. It is a detailed structure figure of an IC chip mounting part. It is the figure which provided the cutting scheduled line in the non-contact IC tag of FIG. It is a figure which shows the directivity of the non-contact IC tag before a cutting | disconnection. It is a figure which shows the directivity of the non-contact IC tag after a cutting | disconnection. It is a figure explaining the difference in directivity. It is a two-dimensional diagram showing the directivity of the non-contact IC tag before cutting. It is a two-dimensional view showing the directivity of the non-contact IC tag after cutting. It is a figure which shows the antenna gain and return loss of the IC tag before cutting. It is a figure which shows the antenna gain and return loss of the IC tag after a cutting | disconnection. It is a figure which shows the other example of the planar antenna element of a non-contact IC tag. It is a figure which shows the directional characteristic of the reader / writer which consists of a planar antenna. It is a plane external view of the non-contact IC tag of the present invention. It is a figure explaining the antenna selection by a diversity function. It is a figure explaining the usage method of the conventional merchandise label.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Non-contact IC tag 2 Small size non-contact IC tag 3 IC chip 4 Planar antenna element, antenna 5 Planned cutting line, perforation line 8 Product management item 11 Base film 41 Half-wave dipole antenna, antenna element 42 Half-wave dipole antenna, antenna Element 43 Hairpin match circuit

Claims (5)

Two dipole planar antenna elements that resonate with radio waves of the same predetermined frequency in the UHF band or the microwave band are connected to two or more antenna input terminals of the IC chip having a diversity function. a non-contact IC tag that is adapted to select the large end of the reception intensity of any of the dipole planar antenna element,
A predetermined cutting line for cutting one of the two dipole planar antenna elements is provided at a position close to the IC chip, and the IC chip does not remain after cutting from the planned cutting line. The function of the dipole type planar antenna element is lost ,
The non-contact IC , wherein the size of the dipole planar antenna element on the side on which the IC chip does not remain is larger than the size of the dipole planar antenna element on the side on which the IC chip remains after cutting along the planned cutting line tag. A short circuit is provided so that a part of the other dipole type planar antenna element is short-circuited to one dipole type planar antenna element so that the other antenna element does not resonate when one antenna element is operating. The non-contact IC tag according to claim 1 , wherein the non-contact IC tag is provided. The non-contact IC tag according to claim 2 , wherein the short circuit is invalidated after being cut from the planned cutting line. Base outer surface in the printer printable like paper substrate of the film is laminated, claim from claim 1, wherein the cutting line so as to penetrate the paper substrate and the base film is formed The non-contact IC tag according to any one of 3 . The product management matters that are at least partially in common with the contents recorded in the memory of the IC chip are printed on the printable surfaces of the paper base on both sides of the planned cutting line. 4. A non-contact IC tag according to 4.

Images