JP2000341170A - Antenna changeover system in storage management system for file of the like utilizing rf-id - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna changeover system that attains stable communication, reduces the cost of the entire system and relieves the load of the maintenance, without the need for a complicated mechanism and device for an antenna layout and switching drive method in the storage maintenance system for files or the like utilizing an RF-ID. SOLUTION: A data carrier reader/writer 2 is provided with a plurality of antennas 8 with respect to one antenna drive circuit 10 for communicating with each data carrier. An antenna changeover section 9 is connected to a read/write control section 11. A program for controlling monitoring and switching of a plurality of the antennas 8 sequentially via the antenna changeover section 9 is installed in the read/write control section 11, and each antenna 8 is sequentially selected when the antenna drive circuit 10 drives the antennas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a so-called RF-I
The present invention relates to an antenna switching method used in a system for storing and managing files by non-contact communication with a file or document (referred to as files) using an antenna using a data carrier system by electromagnetic waves called D. Communication state can be stabilized, and
The present invention relates to an antenna switching method in a file storage management system using a data carrier that enables cost reduction of the entire system.

[0002]

2. Description of the Related Art In recent years, a label-type data carrier having an antenna and a semiconductor IC chip has been attached to a file for the purpose of streamlining storage management of the file and saving labor. Via an antenna, for example, various information for storage management of files, such as a classification code and position information, recorded on a semiconductor IC chip in a data carrier is read without contact, and the information is read by a host computer. A file storage management system using RF-ID, which is searched and checked by collating with a database via the Internet, has been proposed.

For example, a system described in Japanese Patent Application Laid-Open No. Hei 10-334198 discloses an RF-ID document in which a label type data carrier is built by incorporating a semiconductor IC chip and an antenna as shown in FIGS. A document 52 to which a classification label 51 is attached and registered, and a document 52
53 for storing documents, and RF-ID document classification label 5
1. An RF-ID reader 54 for reading the document classification information recorded on the semiconductor IC chip built in 1 in a non-contact manner
And a database 55 of stored documents, a computer 56 having a program for searching or checking stored documents, and the like. RF-ID reader 54
Reads the information between the RF-ID document classification label 51 and the RF-ID reader 54 and reads the information without contacting the RF-ID document classification label 51. And an antenna unit 58 for the same. A plurality of antenna unit units 58 are arranged separately from each other with respect to one read control unit 57 so as to individually read information on each label-shaped data carrier.

[0004] The RF-ID reader 54 is provided with antenna switching units 59 and 60 capable of sequentially switching the antenna unit 58. The RF-ID reader 54 includes an RF-ID document classification label 51 for each stored document. When reading each piece of information in a non-contact manner, each antenna unit 58 is sequentially switched via the antenna switching sections 59 and 60 to communicate with the individual RF-ID document classification labels 51. The RF-ID reader 54 is connected to a computer 56, and can display each information of the read RF-ID document classification label 51 on a display screen 61 of a computer terminal.

[0005] In such a conventional antenna switching system of a file storage management system using RF-ID,
The antenna unit 58 generally includes, as shown in FIG. 10, a read / write control unit 57 for controlling reading and writing of an antenna, and an antenna switching unit 59,
A plurality is provided for 60. Also,
The antenna unit 58 includes an antenna 62, a circuit for modulating and demodulating radio waves transmitted and received via the antenna 62, a circuit for performing DA conversion and AD conversion of transmission signals and reception signals, and the like. The antenna driving circuit 63 is configured to form a pair.

[0006]

However, since the antenna drive circuit has a complicated circuit configuration, a large number of components, and is expensive in itself, the antenna drive circuit is expensive as in the conventional antenna unit. If a circuit and an antenna are configured as a pair, the number of antenna driving circuits must be increased in accordance with the increase in the number of antennas, resulting in an increase in cost. In addition, many of the above file search management systems generally aim to search an enormous number of files, so that the cost is enormous and the maintenance of the antenna drive circuit is very difficult. In particular, in a facility such as a library or a hospital that requires storage of an enormous amount of files, the cost of economic and maintenance work has been enormous.

A conventional file management system using RF-ID includes, in addition to the above-mentioned system, FIG.
As shown in FIG. 1, although an RF-ID reader 65 is configured to communicate with a plurality of data carriers 64 with one antenna, it is possible to communicate with a plurality of data carriers with one antenna. To do so, it is necessary to increase the output of the antenna of the RF-ID reader. However, this is inefficient and uneconomical, and the communication tends to be unstable due to the fact that electromagnetic waves from the antenna easily interfere with other devices. Also, one R
In order to enable the F-ID reader to read a plurality of data carriers, the data carrier and the RF-I
It is necessary to keep a considerable distance from the D-reading device. However, if a person or the like is present between the devices, electromagnetic waves may be cut off and communication may not be possible. Further, instead of increasing the output of the antenna, it is conceivable that the RF-ID reader itself is mechanically moved to scan a plurality of data carriers (not shown). The whole system becomes complicated and extensively configured and controlled, and the cost increases.

Further, in the above-mentioned conventional file management system using RF-ID, the magnetic field distribution of electromagnetic waves is generally uniform by the arrangement of the antenna in the data carrier and the antenna in the RF-ID reader. However, there is a problem that the width of the communication area is narrowed with directivity, and an unstable communication area is generated between the antenna in the data carrier and the antenna of the RF-ID reader. Was. For example, in the conventional file storage management system shown in FIGS. 8 and 9, the antenna 58 of the RF-ID reader 54 is generally placed parallel to the surface to which the data carrier 51 is attached. It is configured such that an electromagnetic wave is sometimes induced to input information reliably. However, for a thin document in which the data carrier cannot be attached to the spine and must be stuck on the side surface perpendicular to the spine surface (that is, the front and back cover surfaces), the RF-ID is used. Since the reader was out of the communication area with the antenna of the reader, electromagnetic waves could not be induced and information could not be input / output.

In general, the performance of the antenna varies slightly depending on the product, and furthermore, the antenna in the data carrier is affected by the installation environment such as the presence of a metal material (for example, an iron plate) near the installation location. The resonance frequency between the antenna and the antenna in the data carrier reading device may be different for each installed antenna or between before and after the installation of the antenna. If the resonance frequency deviates, it is necessary to adjust the frequency of the antenna individually as needed after the antenna is installed, but in general, in a file storage management system, as described above, in order to reliably exchange data carriers, The antenna of the data carrier reading device needs to be provided according to the number of files to be stored. For this reason,
When storing and managing an enormous number of files, it is necessary to provide an enormous number of antennas, so the number of antennas to be readjusted and adjusted becomes enormous, and it takes a great deal of time to readjust the resonance frequency. And it was costly.

Further, in the conventional file storage management system, when a plurality of antenna units are configured,
Generally, each board constituting each antenna unit is configured so that the device address in the system of each unit is recognized by using a dip switch individually. For this reason, when replacing each antenna unit, it is necessary to manually set the DIP switch so that each of the predetermined device numbers can be recognized, which is troublesome in setting, and furthermore, a setting error, etc. And the replacement work of the unit was inconvenient.

In view of the above, the present invention relates to a file storage management system using RF-IDs, which stabilizes communication and eliminates the need for complicated mechanisms and devices for antenna arrangement and switching drive method. It is an object of the present invention to provide an antenna switching method capable of reducing the overall cost and reducing the maintenance burden.

[0012]

In order to achieve the above object, an antenna switching system in a file storage management system using RF-ID according to the present invention comprises a data carrier and a data carrier for inputting / outputting data from / to the data carrier. A read / write device, and a computer having a program and a database for searching and registering data by inputting and outputting information through a data carrier read / write device, and each of the data carriers is divided into a plurality of files. In a system in which the data carriers are mounted and managed by contactlessly communicating between the respective data carriers and the data carrier read / write devices by electromagnetic waves, files are read and written. Communicate with data carriers Provided with a plurality for one antenna driving circuit antennas for the respective antennas it is characterized by being configured to be sequentially selected during driving of the antenna drive circuit.

Preferably, in the present invention, the data carrier read / write device preferably includes one antenna driving circuit and one antenna switching circuit for switching to a predetermined antenna among the antennas and connecting to the antenna driving circuit. Unit, and one read / write control unit that controls data reading, writing, and switching of the antenna,
A plurality of units each including the antenna are serially connected to each other.

In the present invention, preferably, the adjacent antenna driving circuits in the unit are daisy-chain connected to each other, and the adjacent read / write control units are daisy-chain connected to each other. Features.

In the present invention, preferably, each antenna of the data carrier read / write device has a horizontal polarization antenna and a vertical polarization antenna, and any one of the two antennas having different polarizations. It is characterized in that it is configured to be driven by switching between the two.

In the present invention, preferably, one or a plurality of inductive antennas having the same frequency as these antennas are arranged between each antenna of the data carrier read / write device and the antenna of each data carrier. The communication distance between each antenna of the data carrier read / write device and the antenna of each data carrier can be changed.

Preferably, the present invention further comprises an automatic tuning means for synchronizing the resonance frequency of each antenna of the data carrier read / write device and the antenna of each data carrier, and detects a shift when the antenna is out of synchronization. In order to tune to an optimum tuning point.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a file storage management system using an RF-ID employing an antenna switching system according to the present invention. FIG. 2 is a schematic configuration diagram of a data carrier in the file storage management system of FIG. FIG. 3 is a schematic configuration diagram showing an embodiment of an antenna switching method in the file storage management system using RF-ID of the present invention. As shown in FIG. 1, a file storage management system employing an antenna switching system according to the present invention includes a data carrier 1, a data carrier read / write device 2, a file 3 with a data carrier attached thereto, and a data carrier read / write device. 2 with shelves for storing multiple files (not shown)
And a computer 4 for searching the data carrier for various information.

The data carrier 1 is, as shown in FIG.
Semiconductor IC including antenna 5, transmitting / receiving unit 6 and memory 7
And a chip, which is sealed with a synthetic resin or the like and formed in a thin label shape large enough to be attached to the spine of a predetermined document. The data carrier 1 is provided with, for example, a sheet for writing file classification information on its front surface, and an adhesive or the like is applied on its back surface, so that it can be attached to each file (illustration shown). Omitted).

The data carrier read / write device 2 has an antenna 8, an antenna switching unit 9, an antenna drive circuit 10, and a read / write control unit 11, as shown in FIG. The antenna 8 is a header portion for communicating with the antenna 5 of the data carrier 1, and is configured to have directivity, for example, by using a winding coil or a loop, or formed on a printed circuit board. ing. The antenna driving circuit 10 sets a predetermined frequency for sending a read and write command to the data carrier 1 from the antenna 8 based on the signal information.
F. A circuit for performing ASK modulation, a circuit for demodulating the frequency from the data carrier 1 received by the antenna 8 based on signal information, and a digital signal sent from a read / write control unit 11, which will be described later, to analog conversion. A transmission / reception unit 12 including a D / A conversion circuit for enabling the digital signal to be sent to the antenna, and an A / D conversion circuit for digitally converting an analog signal from the data carrier received by the antenna 8. are doing. The antenna switching unit 9 includes, for example, a diode switch, a high-frequency relay, and the like.
On the basis of the signal information sent from 1, the circuit is configured so that the signal sent via the antenna driving circuit 10 is sequentially switched between antennas and transmitted to a predetermined antenna. The read / write control unit 11 is configured by a microcomputer in which a program for controlling input of information recorded on a data carrier and output of information to the data carrier is incorporated.

As shown in FIG. 1, the computer 4 is connected to the data carrier read / write device 2, and the computer 4 searches and collates the file information obtained through the data carrier read device 2, and checks the file information. The various information obtained as a result is displayed on a display device (not shown) of the terminal such as a CRT, and the input information is inputted from the input device (not shown) of the terminal such as a keyboard via the file read / write device 2 to the data. A program that enables input / output to / from the carrier 1 is incorporated.

The antenna driving method in the file storage management system according to the present embodiment is largely characterized by the following configuration. As shown in FIG. 3, a plurality of antennas 8 are connected to one antenna driving circuit 10, and each of the antennas 8 is driven via the antenna switching unit 9 and the read / write control unit 11 when driving the antenna driving circuit 10. Are sequentially selected.

The antenna switching unit 9 is connected to the read / write control unit 11, and the read / write control unit 1
1 includes a program for controlling the antenna drive circuit 10 to perform writing or reading, and a program for monitoring the state of the antenna 8 and controlling the plurality of antennas 8 to be sequentially switched via the antenna switching unit 9. The antenna 8 can be switched through the antenna switching unit 9 and the read / write control unit 11 with little loss and efficiently without taking much time.

In this embodiment, one antenna driving circuit 10, one antenna switching unit 9,
An apparatus configured with a predetermined number of antennas 8 for one read / write control unit 11 is defined as one unit of apparatus.
A plurality of serially connected devices constitute one file read / write device 2. Then, as shown in FIG. 4, a plurality of units are serially connected by connecting the adjacent antenna driving units 10 ₁ to 10 _n in one unit by a daisy chain. Also, one of the antenna drive section 10 ₁ to 10 _n are connected to the read-write controller 11 ₁ to 11 _n. Further, the adjacent read / write control unit 11 _{1 of} each unit
To 11 _n are connected to each other in daisy chain.

Each of the antennas 8 of the data carrier read / write device 2 includes a horizontal polarization antenna and a vertical polarization antenna, and an antenna switching unit 9.
Includes a relay and a diode switch for switching between these antennas having different polarizations. At the time of driving the antenna, the antenna is switched to one of the horizontal polarization antenna and the vertical polarization antenna via the antenna switching unit 9 based on the control information from the data carrier read / write control unit. Has become.

Between the antennas 8 of the data carrier read / write device 2 and the antennas 5 of the data carriers 1 corresponding to the antennas 8, one or more inductive antennas resonating at the same frequency as these antennas are arranged. The communication distance between the antenna 8 and the corresponding antenna 5 of the data carrier 1 can be changed.

As shown in FIG. 3, the antenna drive circuit 10 includes a transmission / reception section 12, an antenna automatic tuning circuit 13
Is provided so that when the tuning of the antenna is shifted, the shift can be detected and the antenna can be tuned to the optimum tuning point.

FIG. 5 is a block diagram for explaining the automatic tuning means of the antenna used in this embodiment. The transmission / reception unit 12 of the antenna driving circuit 10 includes an oscillation and modulation / demodulation circuit. The tuning circuit includes a variable capacitance diode. The automatic antenna tuning circuit 13 includes a tuning control unit 14, an adjustment voltage generator 15, and an oscillation power detector 16. The adjustment voltage generator 15 is configured by a D / A converter or the like,
A predetermined amount of voltage is applied to the variable capacitance diode of the transmission / reception unit 12 according to a command from the tuning control unit 14. The oscillation power detector 16 detects an oscillation voltage when the antenna 8 oscillates by applying a voltage from the adjustment voltage generator 15 to the transmission / reception unit 12 from the transmission / reception unit 12. The tuning control unit 14 is configured to tune to an optimum tuning point of the antenna via an adjustment voltage generator 15 and an oscillation power detector 16 as described later. Then, the automatic tuning of the antenna by the automatic tuning means of the antenna is performed by obtaining a parameter value of an adjustment voltage that maximizes the oscillation power with respect to the antenna connected at the time of initial power-on, and sending the parameter value to the tuning control unit 14. When a plurality of antennas are connected, each antenna is switched, and each parameter value is also sent to the tuning control unit 14 for each antenna and stored. When a change occurs due to a factor, the change is detected, and the change is sent to the tuning control unit 14 as an electric signal, and the voltage of the variable capacitance diode is controlled so that the tuning control unit 14 corrects the change. The program to be executed is incorporated in the tuning control unit 14.

FIG. 6 is a flowchart showing an initial operation procedure of the automatic antenna tuning system in this embodiment. First, the first antenna 8 is selected via the antenna switching unit 9 (step S1), the adjustment voltage of the adjustment voltage generator 15 is set to the minimum value (step S2), and then applied from the adjustment voltage generator 15. The adjustment voltage value and the oscillation power detected by the oscillation power detector 16 via the transmission / reception unit 12 at that time are stored in the tuning control unit 14 (Step S).
3). Next, the adjustment voltage is increased by a predetermined amount (step S
4) The oscillation power at that time is compared with a stored value (step S5). If the oscillation power is larger than the stored value, the adjustment voltage and the oscillation power are stored in the tuning control unit 14 (step S6). Then, the adjustment voltage is increased by a predetermined amount (step S4) to compare the oscillation power with the stored value (step S4).
Steps 5) and the like are repeated until the adjustment voltage reaches the resonance peak value. When the adjustment voltage reaches the resonance peak value, the obtained stored value is stored in the tuning control unit 14 as the adjustment voltage center value (step S7). The setting of the minimum value of the adjustment voltage (step S2) to the storage of the adjustment voltage center value (step S7) are repeated so as to be performed for all antennas. Thereby, the adjustment voltage and the maximum value of the oscillation power in each antenna are stored in the tuning control unit.

FIG. 7 is a flowchart showing the automatic tuning operation procedure of the antenna automatic tuning method in the present embodiment.
When a predetermined antenna 8 is selected via the antenna switch 9 (step S8), the adjustment voltage center value of the corresponding antenna obtained in the initial operation procedure is preset in the adjustment voltage generator 15 (step S9). It is confirmed whether or not the antenna is selected, and if not, the process is terminated (step S10). If the antenna is selected, the adjustment voltage of the adjustment voltage generator 15 is set to a value obtained by subtracting a predetermined value from the center value of the adjustment voltage (step S11), and the adjustment voltage value applied from the adjustment voltage generator 15 and At that time, the oscillation control unit 14 stores the oscillation power detected by the oscillation power detector 16 via the transmission / reception unit 12 (step S12). Next, the adjustment voltage is increased by a predetermined amount (step 13), and the oscillation power at that time is compared with a stored value (step S14). When the oscillation power is larger than the stored value, the adjustment voltage and the oscillation power are stored in the tuning control unit 14 (step S15). Processing such as a predetermined amount increase of the adjustment voltage (step S13) to a comparison between the oscillation power and the stored value (step S14) includes
This is repeated until the adjustment voltage reaches the adjustment voltage center value + the predetermined value. When the adjustment voltage of the adjustment voltage generator 15 reaches the adjustment voltage center value + predetermined value, the adjustment voltage center value is changed to the storage value of the adjustment voltage stored in the tuning control unit 14 (step 15), and thereafter the adjustment voltage is adjusted. Is set to a value obtained by subtracting a predetermined value from the center value of the adjustment voltage (step 11), and processing such as comparing the oscillation power with the stored value (step S14) is repeated. Thus, the antenna can always be adjusted to the optimum tuning point even when the tuning point of the antenna is shifted.

According to the file storage management system using the RF-ID configured as described above, when a file number is input from an input terminal (not shown) of the computer 4 shown in FIG. The data shown in FIG. 2 attached to each antenna 8 and each file stored in a file shelf (not shown) via the read / write controller 11, the antenna drive circuit 10, and the antenna switch 9 of the data carrier read / write device 2 shown in FIG. The antenna 5 of the carrier 1 communicates, and data search and registration are performed by a program and a database built in the computer 4. As a result, the files are stored and managed in a non-contact manner.

At this time, according to the antenna driving method in the file storage management system of the present embodiment, the antenna driving circuit 10 and the antenna 8 are not paired to form an antenna unit, but one antenna driving circuit 1
0, a plurality of antennas 8 are provided, and the state of each antenna 8 is monitored by the read / write control unit 11 and the plurality of antennas 8 are sequentially switched via the antenna switching unit 9. Antenna drive circuit 1 compared to a file storage management system that employs
The number of zeros can be significantly reduced, and a significant cost reduction can be achieved. In addition, since the number of antenna driving circuits 10 can be reduced, the amount of maintenance work of the entire data carrier read / write device can be significantly reduced.
In particular, in a facility such as a library or a hospital which needs to store an enormous amount of files, the effect of reducing the system installation cost and the amount of maintenance work becomes very large. Moreover, since the antenna 8 of the reader 2 is provided corresponding to the antenna 5 of each data carrier 1,
Communication can be performed efficiently and reliably.

There is a limit to the number of antennas 8 that can be switched by one antenna switching unit. This means that the antenna switching unit 9
This is because if the switching is made possible, the influence of electromagnetic wave interference and the like is likely to occur. For this purpose, a method of mechanically providing a moving mechanism in the data carrier reading device to change the position of the data carrier reading device for each predetermined area of the file shelf can be considered, but as described above, the device configuration is more complicated. It is complicated and the cost cannot be reduced. In the present embodiment, the data carrier read / write device 2 is connected to the one antenna switching unit 9 and the antenna driving circuit 1 respectively.
0, the read / write control unit 11
Are provided as a single unit, and a plurality of units are serially connected, and when the antenna switching within one unit is completed, the next Since the antenna switching is performed within the unit, a large number of files can be searched by connecting units having the same configuration without complicating the device configuration and reducing the cost. Further, since the antenna drive circuit 10 and the read / write control unit 11 are connected in a daisy chain, the antenna drive circuit 10 and the read / write control unit 11 need to be adjusted with a dip switch or the like as in the conventional device. If a common product is replaced in each case, the computer can automatically recognize the product address. For this reason, maintenance work can be greatly simplified. Also, an antenna driving circuit,
The read / write control unit can be commonly used in each unit, and the product cost can be reduced.

According to the present embodiment, the antenna 8 of the data carrier read / write device 2 is configured to be switchable to an antenna suitable for polarization and directivity. In consideration of the characteristics, it is possible to exchange data even for files with each data carrier oriented in such a way that information exchange between the data carrier and the data carrier read / write device is not possible depending on the direction of polarization. Become. For this reason, according to the present embodiment, for example, files of different thicknesses can be stored and managed on the same shelf and searched and inspected, and the file can be applied to a storage management system using a data carrier. Range greatly expands.

Further, according to the present embodiment, since the induction antenna which resonates at the same frequency as these antennas is arranged between each antenna of the data carrier read / write device and the antenna of each data carrier, electromagnetic waves are induced. The electromagnetic field distribution is extended. Therefore, the communicable distance between each antenna of the data carrier read / write device and the antenna of each data carrier can be extended without increasing the transmission output of the drive unit. This makes it possible to read and write label information that was difficult to read or write in the past due to the distance between antennas or the direction of misalignment, and by adjusting the position of this inductive antenna, Can be adjusted to a favorable state. In addition, it is preferable that the induction antenna is configured by an antenna having the same polarization plane and is arranged at a position where electromagnetic waves are efficiently guided.

Further, according to the present embodiment, since the antenna automatic tuning means is provided, the resonance frequency of the antenna changes, and reading and writing of the label becomes difficult with the conventional storage management system. Even in this case, it is possible to always automatically adjust to the optimum communication state, and it is possible to greatly reduce the labor and cost for adjustment when a large number of antennas are arranged.

[0037]

As described above, according to the antenna switching system of the present invention, in the file management system using RF-ID, the arrangement of the antenna and the switching driving method do not require complicated mechanisms or devices. In addition, it is possible to stabilize antenna communication and reduce the cost of the entire system.

[Brief description of the drawings]

FIG. 1 shows an RF employing an antenna switching method according to the present invention.
It is a block diagram showing an example of 1 composition of a file storage management system using ID.

FIG. 2 is a schematic configuration diagram of a data carrier in the file storage management system of FIG. 1;

FIG. 3 is a schematic configuration diagram showing an embodiment of an antenna switching method in a file storage management system using RF-ID of the present invention.

FIG. 4 is a block diagram illustrating a connection state of an antenna driving unit and a read / write control unit in the antenna driving method according to the embodiment.

FIG. 5 is a block diagram for explaining automatic tuning means of an antenna used in the present embodiment.

FIG. 6 is a flowchart showing an initial operation procedure of the automatic antenna tuning system in the embodiment.

FIG. 7 is a flowchart showing an automatic tuning operation procedure of the antenna automatic tuning method in the embodiment.

FIG. 8 is a block diagram showing an example of a conventional file storage management system.

FIG. 9 is a diagram showing an overall configuration of an example of a conventional file storage management system.

FIG. 10 is a schematic diagram showing an example of an antenna driving method in a conventional file storage management system.

FIG. 11 is a diagram showing a communication positional relationship between a data carrier and a data carrier read / write device showing another example of a conventional file storage management system.

[Explanation of symbols]

 Reference Signs List 1 data carrier 2 data carrier read / write device 3 files 4 computer 5 antenna 6 transmission / reception unit 7 memory 8 antenna 9 antenna switching unit 10 antenna drive circuit 11 read / write control unit 12 transmission / reception unit (oscillation and modulation / demodulation circuit) 13 antenna drive circuit 14 Tuning control unit 15 Adjustment voltage generator 16 Oscillation power detector

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masayuki Ui 2-2-10 Hatagaya, Shibuya-ku, Tokyo F-term in CABIN INDUSTRY CO., LTD. 5B049 AA06 BB00 CC00 DD05 EE00 EE05 FF09 GG03 GG04 GG07 5B058 CA15 KA21 YA01 5J021 AA02 AA03 AA04 AA05 CA06 DB04 EA04 FA20 FA26 FA30 FA32 HA05 HA10 5K012 AB05 AC07 BA00

Claims (6)

[Claims] A data carrier, a data carrier read / write device for inputting / outputting data from / to the data carrier, and a program and database for searching and registering data by inputting / outputting information via the data carrier reading / writing device are built-in. Computer, the respective data carriers are attached to a plurality of files, respectively, and the respective data carriers and the data carrier read / write device are communicated by electromagnetic waves in a non-contact manner, so that the files are read. In a system adapted to store and manage, the data carrier read / write device is provided with a plurality of antennas for communicating with the respective data carriers for one antenna drive circuit, and each of the antennas drives the antenna drive circuit. Sometimes selected Antenna switching method, characterized by being configured to so that. 2. The data carrier read / write device includes: one antenna driving circuit; one antenna switching unit configured to switch to a predetermined one of the antennas and connect to the antenna driving circuit; The unit according to claim 1, wherein a plurality of units each including a read / write control unit for controlling switching between a writing and an antenna and a plurality of the antennas are serially connected. Antenna switching method. 3. The adjacent antenna drive circuits in the unit are daisy-chain connected to each other, and the adjacent read / write control units are daisy-chain connected to each other. The antenna switching method described in 1. 4. Each of the antennas of the data carrier read / write device has a horizontal polarization antenna and a vertical polarization antenna, and is driven by switching to one of these two antennas having different polarizations. The antenna switching method according to any one of claims 1 to 3, wherein the antenna switching method is configured to perform the following. 5. One or more inductive antennas having the same frequency as these antennas are arranged between each antenna of the data carrier read / write device and the antenna of each data carrier. 5. The antenna switching system according to claim 1, wherein a communication distance between each antenna and each data carrier antenna can be changed. 6. An automatic tuning unit for synchronizing the resonance frequency of each antenna of the data carrier read / write device and the antenna of each data carrier, and detecting the shift when the antenna is out of synchronization, and detecting the optimum tuning point. 6. The antenna switching system according to claim 1, wherein the antenna switching system is tuned.