Communication terminal and information processing system

1. Field of the Invention

The present invention relates to a communication terminal, and, in particular, relates to a communication terminal available for an RFID (Radio Frequency Identification) system and an information processing system including the communication terminal.

2. Description of the Related Art

In the past, as a system for managing articles, there has been developed an RFID system that establishes, on the basis of a non-contact method, communication between a reader/writer generating an induction electromagnetic field and a wireless tag storing therein predetermined information assigned to an article, and transmits information. An example of an RFID system of this type is disclosed in Japanese Unexamined Patent Application Publication No. 2003-99184 and includes an information processing system where an RFID device in the form of a wireless IC tag is embedded within an input pen and when the RFID device and the information processing device including a reader/writer are located within a range within which communication is capable of being established, the information processing device reads out the information of the RFID device and recognizes a pen user or characters written using the pen.

However, since, in the above-mentioned information processing system, the RFID device in the form of the wireless IC tag and the reader/writer being located within a range within which communication is capable of being established is a required operating condition, and a communication distance for a high-frequency wave of an HF band or a UHF band is short, there has occurred a problem that it is possible to establish communication only at a very short distance.

In addition, in Japanese Unexamined Patent Application Publication No. 2001-240217, there is described an inventory management system that includes a plurality of handy terminals establishing communication with a base unit so as to manage inventory in a book shop. However, this handy terminal is a terminal embedding therein a battery and a signal processing circuit, and has a problem that the configuration thereof is complicated and the size thereof is large.

Therefore, preferred embodiments of the present invention provide a communication terminal and an information processing system, which are capable of lengthening a communication distance between a reader/writer and a wireless IC tag on the basis of a simple configuration.

A communication terminal according to a first preferred embodiment of the present invention includes a first antenna unit, a second antenna unit, and a connection unit configured to electrically connect the first antenna unit and the second antenna unit to each other, wherein each of the first antenna unit and the second antenna unit operates with a signal used in one information processing system, and a signal received by the first antenna unit is transmitted from the second antenna unit, and a signal received by the second antenna unit is transmitted from the first antenna unit.

An information processing system according to a second preferred embodiment of the present invention includes a reader/writer, a communication terminal, and a wireless IC tag, wherein the communication terminal includes a first antenna unit, a second antenna unit, and a connection unit configured to electrically connect the first antenna unit and the second antenna unit to each other, wherein the first antenna unit communicates with the reader/writer, the second antenna unit communicates with the wireless IC tag, and information stored in the wireless IC tag is read using the reader/writer.

In the communication terminal, the first antenna unit and the second antenna unit are electrically connected to each other, the first antenna unit communicates with the reader/writer, and the second antenna unit communicates with the wireless IC tag. Since the communication terminal serves as an intermediary between the reader/writer and the wireless IC tag, even if the reader/writer and the wireless IC tag are spaced apart by a long distance at which it is not possible to establish communication based only on the reader/writer and the wireless IC tag, it is possible to establish communication. In addition, a battery and an information processing circuit are unnecessary for the communication terminal, and it is possible to simply configure the communication terminal.

According to various preferred embodiments of the present invention, since the communication terminal serves as an intermediary between the wireless IC tag and the reader/writer, it is possible to lengthen a communication distance.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

FIG. 1 is a perspective view illustrating an information processing system according to a first preferred embodiment of the present invention.

FIG. 2 is a perspective view illustrating a laminated structure of a coiled antenna of a wireless IC tag.

FIG. 3 is a perspective view illustrating an example of a modification 1 to a second antenna unit of a communication terminal.

FIG. 4 is a perspective view illustrating an example of a modification 2 to the second antenna unit of the communication terminal.

FIG. 5 is a perspective view illustrating an example of a modification 3 to the second antenna unit of the communication terminal.

FIG. 6 is a perspective view illustrating an example of a modification 4 to the second antenna unit of the communication terminal.

FIG. 7 is a perspective view illustrating an example of a modification 1 to the wireless IC tag.

FIG. 8 is a perspective view illustrating the wireless IC tag illustrated in FIG. 7 and a booster antenna.

FIGS. 9A and 9B are equivalent circuit diagrams illustrating examples of modifications 2 and 3 to the wireless IC tag.

FIG. 10 is a perspective view illustrating an example of a modification 4 to the wireless IC tag.

FIG. 11 is a perspective view illustrating an example of a modification 5 to the wireless IC tag.

FIG. 12 is a perspective view illustrating an example of a modification 6 to the wireless IC tag.

FIG. 13 is a perspective view illustrating an example of a modification 1 to the communication terminal.

FIG. 14 is a perspective view illustrating an example of a modification 2 to the communication terminal.

FIG. 15 is a perspective view illustrating an information processing system according to a second preferred embodiment of the present invention.

FIGS. 16A and 16B are perspective views illustrating an information processing system according to a third preferred embodiment of the present invention.

FIG. 17 is a perspective view illustrating an information processing system according to a fourth preferred embodiment of the present invention.

Hereinafter, preferred embodiments of a communication terminal and an information processing system according to the present invention will be described with reference to accompanying drawings. In addition, in each drawing, a common symbol is assigned to a same component or a same portion, and redundant description will be omitted.

First Preferred Embodiment

As illustrated in FIG. 1 , an information processing system 100 A according to a first preferred embodiment includes a reader/writer 50 A, a plurality of communication terminals 60 A, and a wireless IC tag 1 A. The reader/writer 50 A includes a main body 51 including an information processing circuit and the like and an electric field-type antenna 53 connected to the main body 51 through a signal line 52 .

The communication terminal 60 A preferably is a pen-shaped reader/writer, and includes a first antenna unit 61 , a second antenna unit 62 , and a connection unit 63 electrically connecting the first and second antenna units 61 , 62 to each other. In addition, these components are housed within a cylindrical housing 64 , and the second antenna unit 62 is disposed in the leading end portion of the housing 64 . The first antenna unit 61 preferably is an electric field-type dipole antenna, and is coupled to the antenna 53 of the reader/writer 50 A due to an electric field. The second antenna unit 62 preferably is a magnetic field-type loop antenna, and, as described hereinafter, is coupled to the coiled antennae 20 A and 20 B of the wireless IC tag 1 A through a magnetic field. The second antenna unit 62 preferably has a loop shape whose area is approximately equal to an area obtained by joining the antennae 20 A and 20 B of the wireless IC tag 1 A together.

The wireless IC tag 1 A includes a wireless IC chip 10 processing a transmission/reception signal of a predetermined frequency and two coiled antennae 20 A and 20 B. The wireless IC chip 10 preferably includes a clock circuit, a logic circuit, a memory circuit, and the like. In addition, in the wireless IC chip 10 , necessary information is stored, and a pair of input-output terminal electrodes (not illustrated) is provided on the rear surface of the wireless IC chip 10 .

The coiled antennae 20 A and 20 B are obtained by winding conductors in a coil shape, one end of each thereof is electrically connected to the input-output terminal electrode of the wireless IC chip 10 , and the other ends thereof are electrically connected to each other. The winding axes of these antennae 20 A and 20 B are disposed at positions different from each other in planar view, and the winding directions thereof are equal to each other. As described hereinafter with reference to FIG. 2 , the antennae 20 A and 20 B are configured by laminating a plurality of coil conductors in a substrate 21 , and the wireless IC chip 10 is mounted on the substrate 21 .

In this information processing system 100 A, a high-frequency wave (of an HF band, a UHF band, or a high-frequency band greater than or equal to the UHF band) radiated from the antenna 53 of the reader/writer 50 A is received by the first antenna unit 61 of the communication terminal 60 A, and transmitted to the second antenna unit 62 through the connection unit 63 . In addition, by causing the second antenna unit 62 disposed in the leading end portion of the housing 64 to be adjacent to the wireless IC tag 1 A, a magnetic flux based on a signal of a predetermined frequency radiated from the second antenna unit 62 penetrates through the coiled antennae 20 A and 20 B, and hence currents flow in the antennae 20 A and 20 B. Specifically, the second antenna unit 62 and the antennae 20 A and 20 B are electromagnetically coupled to each other. This current is supplied to the wireless IC chip 10 to cause the wireless IC chip 10 to operate.

On the other hand, a response signal from the wireless IC chip 10 is radiated from the coiled antennae 20 A and 20 B to the second antenna unit 62 , and the signal is supplied to the first antenna unit 61 through the connection unit 63 , received by the antenna 53 of the reader/writer 50 A, and read by the main body 51 .

Since, in the present first preferred embodiment, each of the first antenna unit 61 and the second antenna unit 62 operates with a signal used in one information processing system 100 A such as a UHF band RFID system, for example, and the communication terminal 60 A serves as an intermediary between the reader/writer 50 A and the wireless IC tag 1 A, even if the reader/writer 50 A and the wireless IC tag 1 A are spaced from each other by a long distance at which it is not possible to establish communication based only on the reader/writer 50 A and the wireless IC tag 1 A, it is possible to establish communication. In particular, since the antenna 53 of the reader/writer 50 A and the first antenna unit 61 of the communication terminal 60 A are coupled to each other through an electric field, it is possible to establish communication at a relatively long distance. In addition, an existing electric field-type antenna is available for the antenna 53 of the reader/writer 50 A. In addition, since the antennae 20 A and 20 B of the wireless IC tag 1 A and the second antenna unit 62 are coupled to each other through a magnetic field, the attenuation of the magnetic field is larger than an electric field and communication is established at a short distance. Therefore, even if a plurality of wireless IC tags 1 A exist, it is possible to reliably read a specific tag 1 A. In addition, since the communication terminal 60 A is wirelessly coupled to the reader/writer 50 A, it is possible to simultaneously read a plurality of wireless IC tags 1 A using a plurality of communication terminals 60 A.

The connection between the first antenna unit 61 and the second antenna unit 62 is subjected to a direct current connection by the connection unit 63 , and it is possible to effectively transmit a signal. In this regard, however, the connection between both thereof may also be a wireless connection such as electromagnetic field coupling. In addition, the communication terminal 60 A is configured by the antenna units 61 and 62 and the connection unit 63 , a power source for driving, such as a battery, the peripheral circuit thereof, and furthermore, a wireless communication device such as Bluetooth (trademark) are not necessary, and it is possible to cause the communication terminal 60 A to be downsized and inexpensive. Furthermore, since the second antenna unit 62 is disposed in the leading end portion of the chassis 64 , it is possible to easily couple the first antenna unit 61 and the second antenna unit 62 to each other.

The communication terminal 60 A preferably is of a pen type, and caused to be adjacent to the wireless IC tag 1 A to be a target of reading, with the housing 64 being held by a hand, and hence the communication terminal 60 A establishes communication with the wireless IC chip 10 . In some cases, a human body also functions as an antenna coupled to an electric field. Accordingly, when the first antenna unit 61 is disposed in a portion to be held in fingers, the human body also functions as an antenna, and the sensitivity of the first antenna unit 61 is improved.

The pen-type housing 64 of the communication terminal 60 A not only simply includes a function as the communication terminal of the RFID system but also may be configured as an article having an actual function. For example, the communication terminal 60 A itself may also be a ballpoint pen or a mobile phone.

As for the wireless IC tag 1 A, since the winding directions of the coiled antennae 20 A and 20 B are equal to each other, currents occurring in the individual antennae 20 A and 20 B do not cancel out each other, and an energy transmission efficiency is improved. Specifically, a communication distance between the second antenna unit 62 and the antennae 20 A and 20 B is lengthened. In addition, the antennae 20 A and 20 B are preferably provided in a laminated structure, and the individual coil conductors thereof are preferably located at positions at which the coil conductors overlap with each other as seen in a planar view. Accordingly, since it is possible to enlarge the opening areas of the coils, and cross fluxes increase, the communication distance further increases.

It is desirable that an imaginary portion of the impedance of the wireless IC chip 10 and imaginary portions of the impedances of the coiled antennae 20 A and 20 B have conjugate relations with each other at the frequency of a signal used for communication. Specifically, it is desirable that the resonance frequencies of the coiled antennae 20 A and 20 B are located near an operation frequency. It is further desirable that real portions of the impedances coincide with each other.

In particular, when the coiled antennae 20 A and 20 B are of a lamination type and have large aperture portions, it is possible to obtain large inductance values with the sizes thereof being small, and furthermore the wireless IC tag 1 A itself is downsized. By setting the operation frequency to a short wavelength in the vicinity of 950 MHz, the wireless IC tag 1 A is further downsized. When the frequency of a UHF band is used for communication, the wireless IC tag 1 A may be put into a size that is about 3.2 mm long, about 1.6 mm wide, and about 0.5 mm tall, for example.

Here, an example of the laminated structure of the coiled antennae 20 A and 20 B will be described with reference to FIG. 2 . The substrate 21 is obtained preferably by forming and laminating electrodes, conductors, and via hole conductors in a plurality of sheets. Electrodes 31 a and 31 b to be connected to the input-output terminal electrodes of the wireless IC chip 10 are provided in the first layer, coil conductors 32 a , 32 b , 33 a , 33 b , 34 a , and 34 b are provided in the second layer to the fourth layer, and a connection coil conductor 35 is provided in the fifth layer. The coil conductors 32 a , 32 b to 34 a , and 34 b are connected in a coil shape through via hole conductors 36 a and 36 b , thereby defining the antennae 20 A and 20 B, and the other ends of the antennae 20 A and 20 B are connected to both end portions of the coil conductor 35 through via hole conductors 37 a and 37 b . In addition, one end of the antenna 20 A and one end of the antenna 20 B are connected to the electrodes 31 a and 31 b through via hole conductors 38 a and 38 b.

While each sheet in the substrate 21 may be formed using a popular resin whose electric permittivity ranges from 3 to 4, for example, it is desirable that the substrate 21 is formed using material whose electric permittivity is higher than that. An example is a ceramic having an electric permittivity that is greater than or equal to 7.

When a lamination type is adopted as the coiled antennae 20 A and 20 B, it is possible to achieve the stability of an operation in addition to enlarging the aperture portion. Specifically, since capacitance between the coil conductors is dependent on the quality of material between the coil conductors (the quality of the material of the sheet), the influence of the electric permittivity of the attachment target article of the wireless IC tag 1 A is reduced (the fluctuation of stray capacitance is less likely to occur), and the change of the inductance value of the coil is small. Therefore, the change of the resonance frequency is small, and the communication distance is stabilized. In particular, by using material of a high electric permittivity for the substrate 21 , the impedance of the coil within the substrate 21 is nearly determined, and becomes unsusceptible to a usage environment.

Since the second antenna unit in the communication terminal may preferably have various shapes, examples of modifications 1 to 4 thereto will be illustrated hereinafter. First, the second antenna unit may be electric field-type antennae 62 A and 62 B that do not have a loop shape but preferably have a flat plate-shaped configuration, as illustrated in FIG. 3 . Since the coiled antennae 20 A and 20 B of the wireless IC tag 1 A are separated into two portions, a potential difference occurs between the individual antennae 20 A and 20 B and an electric field is generated. Therefore, it is possible to cause even the flat plate-shaped electric field-type antennae 62 A and 62 B to operate. In addition, when the electric field-type antennae 62 A and 62 B are used as the second antenna unit, an electric field-type antenna may also be used as the antenna of the wireless IC tag.

As illustrated in FIG. 4 , the second antenna unit may also be a magnetic field-type antenna 62 C that has a loop shape including a plurality of turns. Since the intensity of a magnetic field is strengthened, it is possible to lengthen the communication distance.

As illustrated in FIG. 5 , in the same way as the above-mentioned coiled antennae 20 A and 20 B, the second antenna unit may be configured by a first coiled antenna unit 62 D and a second coiled antenna unit 62 E. One end of the coiled antenna unit 62 D and one end of the coiled antenna unit 62 E are electrically connected to the first antenna unit 61 through the connection unit 63 , and the other ends thereof are electrically connected to each other. In addition, the winding axes of the antenna units 62 D and 62 E are disposed at positions different from each other in planar view, and the winding directions thereof are equal to each other.

Since the winding directions of the coiled antenna units 62 D and 62 E are preferably equal to each other, and the coiled antenna units 62 D and 62 E have the same function effects as the coiled antennae 20 A and 20 B, it is possible to improve an energy transmission efficiency at the time of communication with the wireless IC tag 1 A, and it is possible to lengthen the communication distance. In addition, it contributes to the downsizing of the communication terminal 60 A. In addition, when the antennae 62 D and 62 E of the example of the modification 3 are used, it is not necessary to use two coiled antennae as the wireless IC tag.

As illustrated in FIG. 6 , a matching circuit including inductances L 1 and L 2 and a capacitance C may also be provided in the connection unit 63 (for example, between the second antenna unit 62 and the first antenna unit 61 ). Since it is possible to establish the matching of impedance at an operation frequency, the energy transmission efficiency between the first antenna unit 61 and the second antenna unit 62 is improved, and it is possible to lengthen the communication distance even with small electric power. In addition, as the matching circuit, a circuit configuration other than that illustrated in FIG. 6 may also be adopted.

Next, various kinds of examples of modifications to the wireless IC tag will be described. A wireless IC tag 1 B illustrated in FIG. 7 is obtained by providing external electrodes 23 A and 23 B facing the antennae 20 A and 20 B, respectively, on the surface (bottom surface) of the substrate in which the antennae 20 A and 20 B are embedded. The other configuration is the same as the wireless IC tag 1 A. By providing the external electrodes 23 A and 23 B, it is possible to solder-mount the wireless IC tag 1 B to an article such as a printed circuit board or other suitable device.

In addition, as illustrated in FIG. 8 , as for the wireless IC tag 1 B, meander-shaped booster antennae 24 A and 24 B may also be connected to the external electrodes 23 A and 23 B. While the booster antennae 24 A and 24 B are preferably of an electric field radiation-type, the booster antennae 24 A and 24 B may also be loop-shaped booster antennae of a magnetic field radiation type.

A wireless IC tag 1 C illustrated in FIG. 9A is obtained by electrically connecting the external electrodes 23 A and 23 B provided in the above-mentioned wireless IC tag 1 B to the coiled antennae 20 A and 20 B. In addition, as illustrated in FIG. 9B , capacitances C 1 and C 2 may also be generated between the external electrodes 23 A and 23 B and the coiled antennae 20 A and 20 B.

As illustrated in FIG. 9A , when the external electrodes 23 A and 23 B are electrically directly connected to the coiled antennae 20 A and 20 B, it is possible to simply determine a relationship between the electric potentials of the two, and it is possible to easily design the impedances of the external electrodes 23 A and 23 B to be various values. In addition, as illustrated in FIG. 9B , when being connected through capacitances C 1 and C 2 , since the external electrodes 23 A and 23 B are not directly connected to the wireless IC chip 10 , it is possible to protect the wireless IC chip 10 against the invasion of static electricity.

In addition, the antenna of the wireless IC tag may not include two coiled antennae but may also be one coiled antenna 20 C of one turn as illustrated in FIG. 10 , for example. As illustrated in FIG. 11 , the antenna of the wireless IC tag may also be one coiled antenna 20 D of a plurality of turns. Furthermore, as illustrated in FIG. 12 , the antenna of the wireless IC tag may also be a coiled antenna 25 provided on the front and rear surfaces of a sheet of film 24 . Specifically, a coil conductor 25 a wound more than once may be provided on the front surface of the film 24 , the end portion 25 a ′ thereof may be exposed on the rear surface of the film 24 and connected to the coil conductor 25 b , and the coil conductor 25 b may be exposed on the front surface of the film 24 and connected to the coil conductor 25 c.

In addition, while not illustrated, the winding numbers of the antennae 20 A and 20 B of the wireless IC tag may also be different from each other, and the sizes thereof may also be different from each other. In addition, the number of coiled antennae may also be more than two. For example, another coiled antenna may also be arranged between the coiled antennae 20 A and 20 B.

As for the above-mentioned communication terminal 60 A, as illustrated in FIG. 13 , the connection unit 63 may also be coated using a ferrite material 65 , for example. The line of the connection unit 63 or another ground conductor becomes part of the electric field-type antenna, and influences a radiation characteristic in some cases. By coating the connection unit 63 using the ferrite material 65 , it is possible to isolate the first antenna unit 61 and the second antenna unit 62 from each other, and it is possible to cause the first antenna unit 61 of an electric field type to have a radiation characteristic according to design.

As for the above-mentioned communication terminal 60 A, as illustrated in FIG. 14 , the first antenna unit 61 may also be an electric field-type monopole antenna. The lower half of the first antenna unit 61 preferably is configured as a coaxial line covered by a cylindrical ground electrode 68 , one end of the loop-shaped second antenna unit 62 is connected to the lower end of the first antenna unit 61 , and the other end thereof is connected to the ground electrode 68 .

Since, unlike the above-mentioned dipole antenna, the monopole antenna preferably includes only one conductor, it is possible to simply configure the thin communication terminal 60 A and it is possible to reduce manufacturing costs. In addition, since the lower half is covered by the ground electrode 68 , even if the lower half is held in a hand of a user, the change of a characteristic as an antenna is small.

Second Preferred Embodiment

As illustrated in FIG. 15 , an information processing system 100 B according to a second preferred embodiment includes a reader/writer 50 B including a magnetic field-type loop antenna 54 , a communication terminal 60 B in which the first antenna unit is a magnetic field-type loop antenna 61 B, and the wireless IC tag 1 A. The other configuration is preferably the same or substantially the same as the information processing system 100 A, and the function effect thereof is also same. In particular, in this information processing system 100 B, it is also possible to cause a magnetic field-type antenna to operate as the antenna of the reader/writer.

Third Preferred Embodiment

As illustrated in FIGS. 16A and 16B , in an information processing system 100 C according to a third preferred embodiment, an antenna 55 of the reader/writer 50 A is housed within a holder as a small antenna of an electric field type, and it is possible to insert the antenna 55 into the housing 64 of a communication terminal 60 C so that the antenna 55 is adjacent to the first antenna unit 61 . As illustrated in FIG. 16A , by placing the antenna 55 in the communication terminal 60 C, it is possible to reliably establish communication in a state in which the antenna 55 and the first antenna unit 61 are adjacent to each other. On the other hand, as illustrated in FIG. 16B , by extracting the antenna 55 from the communication terminal 60 C, it is possible to establish communication at a distant point in the same way as in the information processing system 100 A.

In addition, by also downsizing and housing the main body 51 of the reader/writer 50 within the holder 56 or attaching the main body 51 of the reader/writer 50 to the chassis 64 , the reader/writer 50 and the communication terminal 60 C may also be integrated with each other.

Fourth Preferred Embodiment

As illustrated in FIG. 17 , in an information processing system 100 D according to a fourth preferred embodiment, a connector 57 is connected to the leading end of the signal line 52 of the reader/writer 50 A, and it is possible to attach and remove the connector 57 to and from a receptor 66 connected to the extended portion of the connection unit 63 . By connecting the connector 57 to the receptor 66 , it is also possible to connect the reader/writer 50 A and the communication terminal 60 A to each other using a wired line, and it is possible to stably establish communication.

Other Preferred Embodiments

In addition, a communication terminal and an information processing system according to the present invention are not limited to the above-mentioned preferred embodiments, and it should be understood that it is possible to make various modifications without departing the scope thereof.

For example, while, in the above-mentioned preferred embodiments, the wireless IC chip preferably is mounted on the substrate in which the antenna is provided, the wireless IC chip may also be mounted within the substrate. In addition, the antenna may also be provided in the rewiring layer of the wireless IC chip. In addition, an information processing system targeted by this communication terminal is not limited to the UHF band RFID system, and may also be another communication system such as an HF band RFID system or the like.

As described above, preferred embodiments of the present invention are applicable to a communication terminal and an information processing system, and in particular, preferred embodiments of the present invention are superior in terms of lengthening the communication distance between the reader/writer and the wireless IC tag.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.