JP3632110B2 - Code recognition device - Google Patents

Description

[0001]
[Industrial application fields]
INDUSTRIAL APPLICABILITY The present invention is effective when applied to a technique for improving the identifiability of a plurality of tags in a system that reads code information stored in a tag storage means without contact.
[0002]
[Prior art]
A technology that detects the electronic tag that a user owns or wears in a facility such as a ticket gate of a station, a ski resort, or a golf course, and reads information recorded in an IC inside the tag, so-called contact Research on less ID recognition technology has been conducted.
[0003]
Among these, in particular, an electromagnetic wave having a constant frequency (100 to 400 kHz) is emitted from the antenna of the controller, and the operation power is generated in the tag using the electromagnetic induction of the electromagnetic wave, and the ID code stored in the IC is sent to the controller side. The RF / ID (Radio Frequency IDentification) method for replying has been put into practical use.
[0004]
Although the above-mentioned RF / ID method has a difficulty in that only a few bytes of code data can be transmitted because the maximum reading range of the controller is about several mm to 1,000 mm and power generation is performed by electromagnetic induction from the outside of the tag. Since it is not necessary to replace the battery, it can be used by being embedded or sewn in clothing or personal items, and the field of use is expected to expand in the future.
[0005]
[Problems to be solved by the invention]
However, in the conventional RF / ID method of this type, when there are a plurality of tags in the recognition area of the controller antenna, the response signals from the ICs of the tags interfere with each other, making it difficult for the controller to recognize the ID. In many cases, only response signals from tags with good communication conditions can be recognized.
[0006]
The present invention has been made in view of the above points, and an object of the present invention is to identify individual tags even when a plurality of tags exist in the recognition area of the controller in the RF / ID method. Is to provide new technology.
[0007]
[Means for Solving the Problems]
The present invention includes a plurality of sense antennas wound with conductive wires to receive a response code from a tag, an excitation antenna that is arranged around the sense antenna and outputs an excitation electromagnetic wave to the tag, and the plurality of the plurality of sense antennas. Switching means for sequentially switching and receiving response signals from the sense antenna; receiving means for recognizing a response signal received from the sense antenna via the switching means; oscillating means for giving a predetermined oscillation frequency to the excitation antenna; Code recognition comprising a demodulating means for demodulating the response signal recognized by the receiving means, and a control means for controlling the switching means and the oscillating means, and for notifying the demodulated signal obtained by the demodulating means to the host interface in the apparatus, the sense antenna is configured to place in the plane direction a plurality of windings made of conductors on a flat substrate Take-wound body is obtained by increasing the number of turns of the conductor for those disposed in the vicinity of the center than those disposed in the vicinity of the periphery on the plane substrate.
[0011]
[Action]
The inventor's research has revealed that the recognizability is enhanced by arranging the wound bodies side by side in the plane direction. It was also found that when the sense antenna is arranged inside the excitation antenna, the sense antenna arranged near the periphery is more susceptible to the influence of the excitation antenna than the one near the center. In view of this, the present inventor has made the number of turns of the sense antenna arranged in the vicinity of the periphery on the planar substrate smaller than that in the vicinity of the center in order to prevent disturbance of the excitation radio wave from the excitation antenna.
[0013]
That is, when a tag is recognized in the vicinity of the excitation antenna, since it is in the vicinity of the excitation antenna, relatively strong oscillation is possible. Therefore, there is no problem in sensitivity even if the number of turns of the sense antenna that receives the response signal is small.
[0014]
In this manner, the nonuniformity of detection sensitivity is corrected by changing the number of windings depending on the arrangement part of the wound body on the flat substrate.
It should be noted that excitation and reception of a plurality of wound bodies are switched by a switching circuit and scanned, and this switching circuit is controlled by a control circuit.
[0015]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the code recognition apparatus of the present invention. The code recognition device 1 includes a controller unit 2, a scanner unit 3, and an antenna unit 4. The controller unit 2 includes a demodulation circuit 6 and a host interface 7 with a control circuit 5 as a center. The scanner unit 3 includes an oscillation circuit 8, a reception circuit 10, and a switching circuit 11. The antenna unit 4 includes an excitation antenna 12 and a plurality of sense antennas 13.
[0016]
Details of each component will be described below.
(Oscillation circuit 8)
The oscillation circuit 8 provided in the scanner unit 3 performs LC series oscillation by a built-in capacitor C and an excitation antenna L (coil) described later. The oscillation frequency here is 400 kHz or less. This oscillation functions to supply power to the tag by electromagnetic induction and to provide a basic clock for the IC in the tag. Therefore, a simple sine wave is sufficient for oscillation. The operation of the oscillation circuit 8 is controlled by the control circuit 5.
(Excitation antenna 12)
The excitation antenna 12 connected to the oscillation circuit 8 has a function of supplying power to the plurality of tags 15 by electromagnetic induction. In this embodiment, the excitation antenna 12 is disposed in the vicinity of the periphery of the planar base 16 so as to surround the sense antenna 13 as shown in FIG. The excitation antenna 12 may be a conductor made of a copper wire or a nichrome wire with an insulating coating made of a synthetic resin or the like.
(Sense antenna 13)
As shown in FIG. 2, the sense antenna 13 is configured as a plurality of wound bodies disposed on the planar substrate 16. A single sense antenna 13 is fixed on a flat substrate 16 made of an insulating material such as a synthetic resin by winding a plurality of conductive wires made of, for example, a copper wire or a nichrome wire with an insulating coating made of a synthetic resin or the like. In this embodiment, the planar substrate 16 is a synthetic resin substrate having a length of 440 mm and a width of 590 mm. Further, the diameter of the sense antenna 13 was about 53 mm, the number of windings was several tens of turns near the center, and the peripheral part was several turns smaller than that.
[0017]
In FIG. 2, the sense antennas 13 having the same configuration are arranged on the planar substrate 16 in the matrix direction, but may be arranged in the planar direction without any gaps. Furthermore, the number of windings of the sense antenna 13 may be increased for the vicinity of the periphery of the flat substrate 16 to improve the detection sensitivity of the vicinity of the periphery.
[0018]
Furthermore, as shown in FIG. 3, the winding diameter may be changed between the sense antenna 13a (diameter: l2) disposed in the center and the sense antenna 13b (diameter: l2) disposed in the vicinity of the periphery.
(Switching circuit 11)
The switching circuit 11 is composed of an analog multiplexer. In the switching circuit 11, a predetermined address is assigned to each of the plurality of sense antennas 13, and the reception signal of each sense antenna 13 is extracted from the switching circuit 11 in accordance with the switching address (reading address) signal from the control circuit 5. . Therefore, as many switching addresses as the number of sense antennas 13 are allocated.
(Receiving circuit 10)
The excitation antenna 12 described above oscillates at a constant frequency when the tag 15 is not present in the detection area, and a signal (basic oscillation signal) detected from each sense antenna 13 is also constant. However, when the tag 15 is present in the detection area, the response signal is mixed and detected by the sense antenna 13.
[0019]
Since these two signals have different frequencies, the receiving circuit 10 has a function of attenuating the fundamental oscillation signal and amplifying the response signal.
(Demodulation circuit 6)
The demodulating circuit 6 provided in the controller unit 2 has a function of extracting only signals of 1/10 and 1/8 of the fundamental oscillation frequency from the response signal. For example, when the fundamental oscillation frequency is 100 kHz, 10 kHz and 12.5 kHz are extracted.
[0020]
Here, a 1/10 component (10 kHz in this example) of the frequency of the response signal is recognized as “1”, and a 1/8 component (12.5 kHz in this example) is recognized as “0” as a binary signal.
[0021]
Only these frequency components are amplified by an amplifier (not shown) in the demodulation circuit 6.
The demodulation circuit 6 has an FSK (frequency voltage converter), and a binary signal (reading code) is obtained by this FSK.
(Control circuit 5)
The control circuit 5 comprises an 8-bit or 16-bit processing CPU (central processing unit) equipped with a ROM or RAM, sends the switching address to the switching circuit 11 described above, and is demodulated by the demodulation circuit 6. It has a function of reading a reading code.
(Upper interface 7)
The host interface 7 is configured by a serial interface such as RS-232C, for example, and has a function of communicating with the host computer. (Tag structure)
As shown in FIG. 4, the tag 15 includes a coil L that functions as an antenna 21, a rectifier circuit 22, a tag control circuit 23, and a memory 24.
[0022]
The memory 24 is composed of a ROM, and a unique ID code of about 20 to 40 bits is recorded.
The tag control circuit 23 has a function of reading data from the memory 24 and modulating a response signal.
[0023]
The coil L constituting the antenna 21 receives a power supply and a clock signal by electromagnetic induction of the fundamental oscillation signal from the excitation antenna 12 described above. The clock signal is supplied to the tag control circuit 23, and the power supply is rectified to a direct voltage (DC) through the rectifier circuit 22 to operate the tag control circuit 23.
[0024]
When the tag control circuit 23 is given operating power, the tag control circuit 23 reads data (ID code) from the memory 24, generates a response signal, and sends it to the antenna 21. A response signal is output from the antenna 21 to the sense antenna 13 on the code recognition device 1 side.
(Reading timing)
FIG. 6 is a chart showing the read timing from the sense antenna 13 of the control circuit 5 in this embodiment.
[0025]
As shown in the figure, reading is started by a trigger signal (start trigger) generated by the control circuit 5, and a switching address is output from the control circuit 5 to the switching circuit 11 at a predetermined cycle. In accordance with this switching address, read data from each sense antenna 13 is input to the demodulation circuit 6. When such processing is repeated by the number of switching addresses (here, 1 to n), that is, the number of sense antennas (n), a trigger signal (end trigger) indicating the end of reading is output from the control circuit 5 and one cycle. Complete reading.
[0026]
At this time, when there is no read data from the sense antenna 13 specified by the designated switching address, that is, when the tag 15 does not exist in the detection area of the sense antenna, the reading time of the switching address is shortened or You may make it skip and transfer to the next switching address. In FIG. 6, the read code (data) does not exist at the time of cycle S2, which corresponds to this.
[0027]
Such shortening or skip processing can be easily controlled by the ROM in the control circuit. Thus, by shortening or skipping the reading time, the reading time for one cycle can be shortened, and efficient tag recognition becomes possible.
(Entry / exit management system to which this embodiment is applied)
FIG. 5 is a block diagram showing an entrance / exit management system using this system. This figure is a system for managing entry / exit to / from a conference hall in an international conference, for example. International conferences generally limit the area where they can enter depending on the type of job, such as VIP, attendant, SP, and media. In the example of the figure, a scanner (3a, 3b, 3c) is installed for each gate (27a, 27b, 27c), and the name plate of the person entering / exiting is provided by an antenna (4a, 4b, 4c) from this scanner. The embedded tag 15 or ID card format tag 15 can be identified.
[0028]
These gates (27a, 27b, 27c) are provided at the entrance / exit of each zone, and reading information at the time of entry / exit from the scanner (3a, 3b, 3c) is passed through the controller (2a, 2b, 2c). The data is collected by the management computer 25 and recorded in the database 26 of the management computer 25.
[0029]
When identifying the ID from the tag 15 by the scanner (3a, 3b, 3c) for each gate (27a, 27b, 27c), in this embodiment, as described above, a plurality of detection areas of the antennas (4a, 4b, 4c) are provided in the detection area. Even if tags 15 exist, they can be identified almost simultaneously with a single scan of each controller (2a, 2b, 2c), so a large number of people pass through the gate at the start or end of the meeting ID recognition can also be performed efficiently when
[0030]
Further, the management computer 25 can grasp which person is in which area, and can easily call, send a message or make an inquiry. In addition, if an ID holder of an unauthorized level tries to pass through the gate (27a, 27b or 27c), the ID code of the tag 15 read by the scanner (3a, 3b or 3c) is managed. By referring to the database 26 of the computer 25 and notifying the corresponding gate (27a, 27b or 27c) at the judgment of the management computer 25, the gate (27a, 27b or 27c) is immediately shut off, and this ID holder Is prevented from entering from the gate.
[0031]
In this example, an international conference is taken as an example, but it can also be applied to an airport special waiting room, a baseball field, a ball game field, a racetrack, a ski resort, a golf driving range, and the like.
[0032]
【The invention's effect】
According to the present invention, by arranging a sense antenna inside the excitation antenna and using a plurality of winding bodies made of conductors for the sense antenna, it becomes possible to communicate with the tag for each winding body. Therefore, even if a plurality of tags exist in the detection area of the sense antenna, individual tags can be identified without causing interference.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a code recognition device according to the present invention. FIG. 2 is a plan view showing an arrangement state of an excitation antenna and a sense antenna on a flat substrate. FIG. 4 is a block diagram showing a configuration of a tag. FIG. 5 is a block diagram showing a system configuration to which the present invention is applied. FIG. 6 is a chart showing a read timing in a control circuit in an embodiment. Figure [Explanation of symbols]
1 ... code recognition device,
2 ... Controller part,
3 ... scanner part,
4 ... Antenna part,
5 ... Control circuit,
6 ... demodulation circuit,
7: Upper interface,
8: Oscillator circuit,
10: Receiving circuit,
11 ... switching circuit,
12 ... Excitation antenna,
13 ... sense antenna,
13a ... sense antenna,
13b ... sense antenna,
15 ... tag,
16 ... planar substrate,
21 ... Antenna,
22 ... Rectifier circuit,
23. Tag control circuit,
24 ... Memory,
25 ... management computer,
26 ... Database,

Claims (1)

A code recognition device that reads code information from an IC provided in a tag in a non-contact manner, and is arranged around a plurality of sense antennas wound with conductive wires to receive a response code from the tag. , An excitation antenna that outputs an excitation electromagnetic wave to the tag, a switching unit that sequentially switches and receives response signals from the plurality of sense antennas, and a reception unit that recognizes a response signal received from the sense antenna via the switching unit Oscillating means for applying a predetermined oscillation frequency to the excitation antenna, demodulating means for demodulating the response signal recognized by the receiving means, and the switching means and the oscillating means, and obtained by the demodulating means. Control means for notifying the demodulated signal to the host interface ,
In the sense antenna, a plurality of winding bodies made of conductive wires are arranged in a plane direction on a flat substrate, and the winding bodies are arranged near the center rather than those arranged near the periphery on the flat substrate. A code recognizing device characterized in that an object has increased the number of windings of a conductor .

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