JP3526496B2 - Non-contact identification device for access control - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for identifying a person, an animal, or an object entering or leaving a specific building, room, or the like due to the necessity of security management or confidentiality. When a question is asked by radio waves, a person, animal, or object holds a card-shaped responder that responds to the question with a response radio wave that represents a unique identification code, and the responder does not touch the responder. The present invention relates to a contactless identification device for entering / exiting management, which is adapted to identify a.

[0002]

2. Description of the Related Art A conventional contactless identification device for entering / exiting management of this type is an Av issued by the applicant of the present application, Japan Avionics Co., Ltd., Technical Journal Editorial Committee, on March 31, 1995.
io Technical Report, Vol. 16, No. 1, 1995 pp.
30-34 "Development of access control system"
Is disclosed in a technical report entitled. The contactless identification device for entry / exit management reported in this technical report asks a responder called an RFID card from a questioner called a reader with a questioning radio wave, and the interrogator receives a response radio wave from the responder and responds. By identifying the identification information carried on the radio wave, the identification information of the responder is identified without touching the responder. The interrogator and transponder each have an antenna, and transmit and receive radio waves by electromagnetic induction. The interrogator antenna is a loop antenna. The carrier frequency of the transmitted and received radio waves of the interrogator and the transponder is 125 KHz. The transponder is
Since the energy of the interrogation radio wave is used as a power source, no special power source is required. Therefore, the power supply system of the transponder is a passive power supply system. As a device used as such a transponder, there is a "signal identification device" in Japanese Patent Publication No. 62-43238. In this “signal identification device”, the coil constitutes an antenna.

[0003]

In the above-mentioned conventional contactless identification device for entrance / exit management, since the responder adopts the passive power supply system, the detection distance is short. If the aperture area of the loop antenna of the interrogator is increased, the received signal level can be increased. However, if the aperture area of the loop antenna is increased, the noise included in the received signal also increases and the signal-to-noise ratio (S / S) of the received signal increases. N ratio) cannot be improved and the detection distance cannot be increased. The same applies when the number of turns of the loop antenna is increased.

Further, in the above-mentioned conventional contactless identification device for entrance / exit management, the identification information of the responder can be identified, but in order to determine the moving direction of the responder, that is, the person holding the responder or the like from the entrance / exit. A different device is needed to determine whether it has entered or left. In order to determine the traveling direction at the entrance / exit, the following method can be considered, for example. First, as a first method, two conventional contactless identification devices for entrance / exit management are provided, and the first contactless identification device for entrance / exit management and the second contactless identification device for entrance / exit management are the same identification first. A method of determining entrance / exit depending on whether information has been detected can be considered. As a second method, a single contactless identification device for entrance / exit management is provided, and a plurality of infrared detecting elements are provided separately from the contactless identification device for detecting the traveling direction of the person to be identified in parallel with the traveling direction. A method of preparing for is conceivable. It is intended to detect the traveling direction of the person to be identified from the detection order of the plurality of infrared detection elements. However, in any of the above-described first and second methods, it is necessary to add another device in addition to the one contact / non-contact identification device for entrance / exit management, so that the entire device becomes expensive.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a contactless identification device for entrance / exit management which has a simple structure and can detect even a passive power source type transponder at a sufficient distance and can detect the direction of entrance / exit.

[0006]

In order to solve the above problems, the present invention provides the following means.

[0007] An antenna is provided near an entrance or a passage through which a person, an animal, or an object passes, and a small-sized responder such as a card held by the person, the animal, or the object is connected to the antenna from the antenna. When a question is asked by radiating an inquiry radio wave, and when the responder responds to the question with a response electric wave that represents an identification code unique to itself, the response electric wave is received by the antenna and displayed by the response electric wave. In the contactless identification device for entrance / exit management for identifying the person, animal or object corresponding to the identification code, the antennas are spaced from each other in the traveling direction of the person, animal or object at the entrance or the passage. The first and second loop antennas are arranged so that the person, the animal, or the object passes through the respective loops, and the output of the first loop antenna and the second loop antenna are provided. A first subtraction circuit that generates a difference signal between the output of the second loop antenna and a second subtraction circuit that generates a difference signal between the output of the second loop antenna and the output of the first loop antenna; A first demodulation circuit that demodulates the output of the first subtraction circuit, a second demodulation circuit that demodulates the output of the second subtraction circuit, and an output of the first and second demodulation circuits are identified. When the identification code that identifies and recognizes the output of the first demodulation circuit is the first identification code, and the identification code that identifies and recognizes the output of the second demodulation circuit is the second identification code. , The first identification code and the second identification code are the same, and when the first identification code is identified and then the second identification code is identified, the person, animal or object is Moving from the first loop antenna toward the second loop antenna, The person when identifying the first identification code after the identifying code,
A non-contact identification device for entrance / exit management, comprising means for determining that an animal or an object has moved in a direction from the second loop antenna to the first loop antenna.

A region in which the response radio wave can be received by the first antenna and is outside the response radio wave reception region by the second antenna is A, and the response radio wave is received by the first antenna. B is a receivable area of the response radio wave by the second antenna and B is a receivable area of the response radio wave by the second antenna, and is a receivable area of the response radio wave by the first antenna. When the area outside the receivable area is designated as C, the area B is a part of the space sandwiched by the loop surfaces of the first and second loop antennas, and the entry / exit management non-use is as described above. Contact identification device.

Each of the first and second loop antennas has a vertically long rectangular loop surface.
2. The contactless identification device for entrance / exit management according to the above or, wherein the loop planes of the loop antenna are parallel to each other, and the loop planes are substantially orthogonal to the traveling direction.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments of the present invention.

FIG. 1 is a perspective view showing a loop antenna and a receivable area of a response radio wave for explaining the concept of the embodiment of the present invention, and FIG. 2 is a loop antenna for explaining the concept of the embodiment. And FIG. 3 is a plan view showing the receivable area of the response radio wave, FIG. 3 is a block diagram showing the configuration of the embodiment, and FIG. 4 is a diagram showing the received signal level in each receivable area in FIGS.

As shown in FIG. 3, in this embodiment, an input antenna 1, an output antenna 2 and subtraction circuits 3 and 4 are provided.
And filter and demodulation circuits 5 and 6, and a microprocessor unit (MPU) 7. The transponder to be identified is the RFID card described in the section of the related art, and its power source is a passive power source system.

Each of the input antenna 1 and the output antenna 2 is a loop antenna for transmitting an inquiry radio wave and receiving a response radio wave of a transponder, and is a rectangle having a length of 2 meters and a width of 1 meter (b in FIG. 2). Form a loop surface. The loop surface is a plane including the center of a rectangular loop conductor and having a peripheral edge defined by the loop conductor. The loop planes of the input antenna 1 and the output antenna 2 are parallel to each other, and the axes passing through the centers of the loop planes of both antennas coincide with each other. The distance a between the loop surfaces of the input antenna 1 and the output antenna 2 is 60 cm. In FIG. 3, the interrogation signal transmission circuit for transmitting the interrogation signal to both antennas is omitted. One interrogation signal transmission circuit is provided, and one interrogation signal transmission circuit supplies interrogation signals to the input antenna 1 and the output antenna 2 in common. The transmission interval of the inquiry signal is 1/100 second. The carrier frequency of the interrogation signal and the response signal is 125
KHz. The subtraction circuit 3 and the filter and demodulation circuit 5 form a first reception circuit, and the subtraction circuit 4 and the filter and demodulation circuit 6 form a second reception circuit.

The MPU 7 includes filter and demodulation circuits 5 and 6.
Of the filter and the demodulation circuit 5 is identified and recognized as a first identification code, and the output of the filter and the demodulation circuit 6 is identified and recognized as a second identification code. When the identification code is used, the first identification code and the second identification code are the same, and when the first identification code is identified and then the second identification code is identified, a person,
A transponder attached to an identification object such as an animal or an object moves in a direction from the input antenna 1 to the output antenna 2, identifies the second identification code, and later identifies the first identification code. When this is done, the transponder attached to the identification target is means for determining that the transponder has moved in the direction from the output antenna 2 to the input antenna 1.

Next, the operating principle of this embodiment will be described.
In FIGS. 1 and 2, A is a response radio wave receivable area by reception of the input antenna 1 (excluding response radio wave receivable area by reception of the output antenna 2), and B is reception of the input antenna 1. Is a response radio wave receivable area due to the reception of the output antenna 2, and C is a response radio wave reception area due to the reception of the output antenna 2 (however, the reception antenna 1 receives (Excluding the response radio wave receivable area by D.), D is outside the response radio wave receivable area by the receiving antenna 1 and is outside the response radio wave receiving area by the output antenna 2. is there. The area B is in the center of the space sandwiched by the loop surfaces of the input antenna 1 and the output antenna 2.

FIG. 4 is a diagram showing the relationship of the received signal level of the response signal in each of these areas. As shown in the figure, in the area A, the reception signal level Fs by the input antenna 1 is
1 is considerably higher than the received signal level Fs2 by the output antenna 2 (Fs1 Fs2). In the area B, the input antenna 1
The received signal level Fs1 due to and the received signal level Fs2 due to the output antenna 2 are almost equal (Fs1 ≈ Fs2). Area C
Then, the received signal level Fs1 by the input antenna 1 is considerably smaller than the received signal level Fs2 by the output antenna 2 (Fs1 Fs2). In the area D, the received signal level Fs1 by the input antenna 1 and the received signal level Fs2 by the output antenna 2 are both below the receivable limit (Fs1 ≈ 0
, Fs2 ≈ 0).

On the other hand, the noise source is generally far away from both the input antenna 1 and the output antenna 2. Therefore, the noise level received by antenna 1 is Fn.
Then, it is practically acceptable to expect that the noise level received by the output antenna 2 is also Fn.

From the above, the sum of the signal level and the noise level at the output of the input antenna 1 is Fn + Fs1, and the sum of the signal level and the noise level at the output of the output antenna 2 is Fn + Fs2. The subtraction circuit 3 subtracts the output Fn + Fs2 of the output antenna 2 from the output Fn + Fs1 of the input antenna 1. As described above, it can be considered that the noise source is considerably distant from both the input antenna 1 and the output antenna 2. Therefore, the input antenna 1 and the output antenna 2 can be considered.
The phases of the noises received by are matched, the noise components are canceled by the subtraction circuit 3, and the subtraction circuit 3 outputs the input antenna 1
The reception signal Fs1 of is output.

The subtraction circuit 4 outputs the output Fn + of the output antenna 2.
The noise component Fn is canceled by subtracting the output Fn + Fs1 of the input antenna 1 from Fs2, and the received signal of the output antenna 2 is canceled.
Output Fs2.

The filter and demodulation circuit 5 receives the output Fs1 of the subtraction circuit 3, removes high frequency noise with a filter, demodulates the signal component obtained by removing the noise, and demodulates the signal of the identification code transmitted from the responder. To generate. Similarly, the filter and demodulation circuit 6 receives the output Fs2 of the subtraction circuit 4, removes high frequency noise with the filter, demodulates the signal component obtained by removing the noise, and outputs the signal of the identification code transmitted from the responder. To generate.

The MPU 7 identifies the output of the filter and demodulation circuit 5 to generate a first identification code, and identifies the output of the filter and demodulation circuit 6 to generate a second identification code.
When the MPU 7 has the same first identification code and the second identification code, and identifies the second identification code after identifying the first identification code, the ,
The transponder attached to the object to be identified such as an object is the input antenna 1
From the output antenna 2 to the output antenna 2.
Further, when the MPU 7 identifies the second identification code and then identifies the first identification code, the transponder attached to the identification target moves in the direction from the output antenna 2 to the input antenna 1. Judge that it has moved. The MPU 7 detects the first identification code and the second identification code, and the unique names and product numbers of people, animals, objects, etc., and the first identification code respectively corresponding to the first identification code and the second identification code. However, when the second identification code having the same content is not detected within the predetermined time, or when the second identification code is detected but the first identification code having the same content is detected within the predetermined time. The alarm signal when there is not, and the moving direction of the identification target determined by the above are output to an output device such as a display and a printer, and also transmitted to a terminal device connected by a communication line. The predetermined time is the time that normally takes for the object to be identified to pass through the area B, plus a margin time of about 20%.

For example, this embodiment is provided at a doorway of a building, and a responder storing a unique identification code is held by a person M1 who is associated with the identification code in advance, and the identification code and the name of the person M1 are stored. By registering in advance in the MPU 7 in association with each other, when the person M1 enters the area A, the MPU 7 first recognizes it as the first identification code, and then in the area B, the person M1 sometimes recognizes that person M1. The identification code of 1 is temporarily cut off, and when the person M1 enters the area C, MP
U7 identifies the second identification code having the same content as the first identification code. Through this series of identification operations, it is recognized that the person M1 has entered the building. When the person M2 leaves the building, the second identification code is identified first, and then the first identification code having the same content as the second identification code is identified. By providing the inner wall surface of the entrance / exit passage at the position of the chain double-dashed line in FIG. 2, a person moves to another passage between the input antenna 1 and the output antenna 2, and the input antenna 1 is removed. It is possible to avoid a situation in which the antenna 2 does not pass even though it has passed.

As described above, according to the present embodiment, it is possible to detect the entering / exiting direction of an object such as a person, an animal, or an object with a simple structure, and it is sufficient even if the responder power supply system is a passive power supply system. Objects can be detected at various distances.

Although the present invention has been specifically described with reference to the embodiments, the present invention is not limited to these embodiments and can be implemented in various forms within the scope of the claims. There is no need to explain what you can do.

[0025]

As described in detail above, according to the present invention, the direction of entry and exit of an object such as a person, an animal, or an object can be detected by a device having a simple structure, and the power supply system of the responder is a passive power supply system. However, the object can be detected at a sufficient distance.

[Brief description of drawings]

FIG. 1 is a perspective view showing a loop antenna and a response radio wave receivable area for explaining the concept of an embodiment of the present invention.

FIG. 2 is a plan view showing a loop antenna and a response radio wave receivable region for explaining the concept of the embodiment.

FIG. 3 is a block diagram showing the configuration of the embodiment.

FIG. 4 is a diagram showing received signal levels in respective receivable areas in FIGS.

[Explanation of symbols]

1 ... Input antenna 2 ... Output antenna 3, 4 ... Subtraction circuit 5, 6 ... Filter and demodulation circuit 7 ... Microprocessor unit ( MPU) A ... Receivable radio wave reception area by reception of the input antenna 1 (excluding response radio wave reception area by reception antenna 2) B ... Input antenna 1 and output Receivable radio wave receivable area due to reception of the receiving antenna 2 C ... Receivable radio wave receivable area due to reception of the output antenna 2 (excluding response electric wave receivable area due to reception of the input antenna 1) D. .... Receiving area of response radio wave due to reception of input antenna 1 and output antenna 2

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G07C 1/00-15/00 G07B 11/00-17/04 G08B 13/00-15/02 G01V 1 / 00-13/00

Claims (3)

(57) [Claims] 1. A small-sized transponder, such as a card type, which has an antenna provided near an entrance or a passage through which a person, an animal, or an object passes and which is held by the person, the animal, or the object. When a question is asked by radiating an inquiry radio wave from an antenna, and when the responder responds to the question with a response radio wave that represents an identification code unique to itself, the response radio wave is received by the antenna and the response radio wave is received. In the contactless identification device for entrance / exit management for identifying the person, the animal or the object corresponding to the identification code represented by, the antennas are spaced apart from each other in the traveling direction of the person, the animal or the object at the entrance or the passage. The first and second loop antennas are arranged so that the person, the animal, or the object passes through the respective loops, and the output of the first loop antenna and the second loop antenna are provided. A first subtraction circuit for generating a signal of a difference from the output of the tenor; a second subtraction circuit for generating a signal of a difference between the output of the second loop antenna and the output of the first loop antenna; A first demodulation circuit that demodulates the output of the first subtraction circuit, a second demodulation circuit that demodulates the output of the second subtraction circuit, and an output of the first and second demodulation circuits are identified. When the identification code that identifies and recognizes the output of the first demodulation circuit is the first identification code, and the identification code that identifies and recognizes the output of the second demodulation circuit is the second identification code. , The first identification code and the second identification code are the same, and when the first identification code is identified and then the second identification code is identified, the person, animal or object is Moving in a direction from the first loop antenna to the second loop antenna,
When the first identification code is identified after the identification of the second identification code, it is determined that the person, animal or object has moved in the direction from the second loop antenna to the first loop antenna. A contactless identification device for entering / exiting management, comprising: 2. A region where the response radio wave can be received by the first antenna and is outside the response radio wave reception region by the second antenna, and A is the response radio wave by the first antenna. B is a receivable area of the response radio wave by the second antenna, and B is a receivable area of the response radio wave by the second antenna, and is the response by the first antenna. When the area outside the radio wave receivable area is C, the area B
Is a part of a space sandwiched by the loop surfaces of the first and second loop antennas, and the contactless identification device for entrance / exit management according to claim 1. 3. The first and second loop antennas each have a vertically long rectangular loop surface, the loop surfaces of the first and second loop antennas are parallel to each other, and the loop surfaces are The contactless identification device for entrance / exit management according to claim 1 or 2, wherein the contactless identification device is substantially orthogonal to the traveling direction.