JP2011199746A - Portable field communication device with stray capacitance sensor, and field communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent spatial propagation to an approaching object.SOLUTION: A storage section 11 stores a predetermined reference capacitance value Th. A transmission section 15 transmits information (data), such as identification information ID by an electric field from a first communication electrode 16a and a second communication electrode 16b. A detection electrode 12 detects stray capacitance C generated between the communication device and the approaching object and having a value changing depending on the magnitude of a distance from the object; a measurement section 13 measures the value of the detected stray capacitance C; and if the measured value of the stray capacitance C exceeds a reference value, a control section 14 stops transmission of the information (data).

Description

  The present invention relates to a technique for performing electric field communication by inducing an electric field from an electrode into an electric field transmission medium.

  2. Description of the Related Art Conventionally, there has been proposed an electric field communication device that performs communication by inducing an electric field based on information to be transmitted to an electric field transmission medium and detecting an electric field induced in the electric field transmission medium (see Patent Document 1). ).

  At present, a portable electric field communication device in which such an electric field communication device is miniaturized has been developed, and when an owner who has the portable electric field communication device comes into contact with a predetermined area electrode, Identification information or the like is transmitted from the portable electric field communication device to the area electrode via the owner, and can be received by the authentication electric field communication device connected to the area electrode to authenticate the contact to the area electrode. It has become.

JP 2003-324395 A

  However, when the owner is close to another person, a transmission path based on stray capacitance is formed with the other person, so that the owner's identification information, etc. is transmitted from the owner to the other person through the space. There was a problem of unexpected behavior.

  For example, as shown in FIG. 7, when another person B existing in front of the owner A is in contact with the area electrode 3 and the owner A is close to the other person B, the portable person possessed by the owner A The stray capacitance C is generated in the close space between the type electric field communication device and the other person B, and the identification information of the holder A is transmitted to the area electrode 3 through the transmission path based on the stray capacitance C. Another person B who is a non-owner of the type electric field communication apparatus is erroneously recognized as the owner A.

  The present invention has been made in view of the above problems, and an object thereof is to prevent spatial propagation to a close object.

  According to the first aspect of the present invention, a fixed reference value is stored in a portable electric field communication device with a stray capacitance sensor capable of performing electric field communication by inducing an electric field from a communication electrode to an electric field transmission medium. Detects stray capacitance that occurs between a storage unit, a transmission unit that transmits predetermined information from the communication electrode by an electric field, and a nearby object, and the value of which varies depending on the distance to the object. A detection electrode that performs measurement, a measurement unit that measures the value of the detected stray capacitance, and a control unit that stops transmission of the predetermined information when the measured value of the stray capacitance exceeds the reference value; It is characterized by having.

  According to the present invention, in the portable electric field communication device with a stray capacitance sensor capable of inducing electric field from the communication electrode in the electric field transmission medium and performing electric field communication, the storage means for storing a constant reference value; A sensing electrode that detects a stray capacitance that occurs between a transmitting unit that transmits predetermined information from a communication electrode by an electric field and a nearby object and changes in value according to the distance between the object and the object, Propagation in space to nearby objects because it has measuring means for measuring the value of the detected stray capacitance and control means for stopping transmission of predetermined information when the measured stray capacitance value exceeds the reference value Can be prevented.

  According to a second aspect of the present invention, the detection electrode and the communication electrode are composed of the same electrode, the electrodes are two electrodes facing each other, and the control means detects the stray capacitance detected by one of the electrodes. When the value is larger than the value of the stray capacitance detected by the other electrode, the transmission of the predetermined information transmitted from the other electrode is stopped.

  According to the present invention, the detection electrode and the communication electrode are composed of the same electrode, and the electrodes are two electrodes facing each other, and the control means determines that the value of the stray capacitance detected by one electrode is the other electrode. Since transmission of the predetermined information transmitted from the other electrode is stopped when the value of the detected stray capacitance is larger, it is possible to more reliably prevent spatial propagation to a close object.

  According to a third aspect of the present invention, there is provided an electric field communication method in which a portable electric field communication device with a stray capacitance sensor capable of performing electric field communication by inducing an electric field from a communication electrode to an electric field transmission medium, A first step of storing a value in the storage means, a second step of transmitting predetermined information from the communication electrode by an electric field, and a distance between the object and the adjacent object. A third step of detecting a stray capacitance whose value changes in accordance with the size with a detection electrode; a fourth step of measuring a value of the detected stray capacitance; and a value of the measured stray capacitance And a fifth step of stopping transmission of the predetermined information when the reference value is exceeded.

  According to a fourth aspect of the present invention, the detection electrode and the communication electrode are composed of the same electrode, the electrodes are two electrodes facing each other, and the fifth step is detected by one electrode. When the value of the stray capacitance is larger than the value of the stray capacitance detected by the other electrode, transmission of the predetermined information transmitted from the other electrode is stopped.

  According to the present invention, it is possible to prevent spatial propagation to a close object.

It is a figure which shows the functional block structure of the portable electric field communication apparatus with a stray capacitance sensor which concerns on Example 1. FIG. It is a figure explaining the processing operation of the portable electric field communication apparatus with a stray capacitance sensor according to the first embodiment. It is a figure which shows the processing flow of the portable electric field communication apparatus with a stray capacitance sensor which concerns on Example 1. FIG. It is a figure which shows the functional block structure of the portable electric field communication apparatus with a stray capacitance sensor which concerns on Example 2. FIG. It is a figure explaining the processing operation of the portable electric field communication apparatus with a stray capacitance sensor according to the second embodiment. It is a figure which shows the processing flow of the portable electric field communication apparatus with a stray capacitance sensor which concerns on Example 2. FIG. It is a figure explaining the processing operation of the conventional portable electric field communication apparatus.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a functional block configuration of a portable electric field communication device with a stray capacitance sensor according to the first embodiment. The portable electric field communication device 1 with a stray capacitance sensor includes a storage unit 11, a detection electrode 12, a measurement unit 13, a control unit 14, a transmission unit 15, a first communication electrode 16a, and a second communication electrode. 16b. The functions of these functional units will be described below, and the overall processing operation will be described, and the effects will be described later.

  The storage unit 11 includes a constant reference capacitance value Th (threshold value) used when the control unit 14 compares the stray capacitance value, an identification information ID for uniquely identifying the portable electric field communication device 1 with a stray capacitance sensor, and the like. It has a function of storing various information (data) in a readable manner. In addition, as such a memory | storage part 11, it can be comprised by memory, a storage, etc., for example.

  The detection electrode 12 is disposed on one surface of the casing forming the outer shape of the portable electric field communication device 1 with a stray capacitance sensor, and is located between adjacent objects that are close to the portable electric field communication device 1 with a stray capacitance sensor. It has a function of detecting stray capacitance C generated in Note that the detection electrode 12 can be formed of, for example, a metal electrode, and the function of the detection electrode 12 can be achieved using the first communication electrode 16a and the second communication electrode 16b that are similarly formed of metal electrodes. It can also be realized (for example, one metal electrode can be used as the detection electrode 12 and the first communication electrode 16a).

  The measurement unit 13 has a function of measuring the value of the stray capacitance C detected by the detection electrode 12. The detection electrode 12 and the measurement unit 13 operate as a stray capacitance sensor in the portable electric field communication device 1 with a stray capacitance sensor.

  The control unit 14 acquires the reference capacitance value Th from the storage unit 11, compares it with the value of the stray capacitance C measured by the measurement unit 13, and controls the transmission process of the transmission unit 15 based on the comparison result. It has a function.

  The transmission unit 15 induces an electric field from the first communication electrode 16a and the second communication electrode 16b arranged to face the surface of the casing to the electric field transmission medium in contact with the portable electric field communication device with a floating capacitance sensor 1. In addition, it has a function of transmitting information such as identification information ID stored in the storage unit 11 in advance to another electric field communication device. In addition, since the specific technique which transmits by an electric field is the same as what was described in patent document 1 (especially FIG. 2 and its description location), the description shall be abbreviate | omitted here.

  Next, the operation of the portable electric field communication device 1 with a stray capacitance sensor according to the first embodiment will be described. FIG. 2 is a diagram for explaining the processing operation of the portable electric field communication device 1 with the stray capacitance sensor according to the first embodiment. FIG. 3 is a diagram illustrating a processing flow of the portable electric field communication device 1 with the stray capacitance sensor according to the first embodiment. It is assumed that the holder A carrying the portable electric field communication device 1 with a stray capacitance sensor is in contact with the area electrode 3 connected to the electric field communication device 5 for authentication. 1, it is assumed that information (data) such as identification information ID is read from the storage unit 11 and output (transmitted) to the holder A as an electric field transmission medium.

  Here, when another person B who is a non-owner of the portable electric field communication device 1 with a stray capacitance sensor comes close to the owner A, the portable electric field communication device 1 with a stray capacitance sensor possessed by the owner A A stray capacitance C that changes in value according to the size of the distance D between the other person B (the value is larger as the distance D is smaller and the value is smaller as the distance D is larger) is generated.

  First, the detection electrode 12 detects the stray capacitance C generated between the portable electric field communication device 1 with the stray capacitance sensor of the holder A and the other person B (S1), and the detection unit 13 detects the stray capacitance C at S1. The value of the stray capacitance C is measured (S2).

  Next, the control unit 14 reads the reference capacitance value Th from the storage unit 11, and compares the reference capacitance value Th with the value of the stray capacitance C measured in S2 (S3).

  Next, when the value of the measured stray capacitance C exceeds the reference capacitance value Th as a result of the comparison in S3, the control unit 14 transmits a stray capacitance detection signal to the authentication electric field communication device 5 (S4). .

  Next, after receiving a transmission stop signal from the authentication electric field communication device 5 that has transmitted the stray capacitance detection signal, the control unit 14 stops transmission of information (data) such as the identification information ID by the transmission unit 15 (S5). ). The control unit 14 does not transmit the stray capacitance detection signal to the authentication electric field communication device 5 when the value of the stray capacitance C measured exceeds the reference capacitance value Th as a result of the comparison in S3. Immediately, transmission of information (data) by the transmission unit 15 can be stopped.

  Note that the reference capacitance value Th used for comparison with the value of the stray capacitance is desirably set in the range of 10 fF to 1 pF. Further, since whether or not spatial propagation occurs has a predetermined relationship with the carrier frequency used by the portable electric field communication device with a stray capacitance sensor 1, it is desirable that the carrier frequency be 1 MHz to 15 MHz. In addition, the detection electrode structure is pre-patterned based on the relationship between the stray capacitance generated between the adjacent objects and the distance between the adjacent objects, thereby enabling adjustment of the range in which the stray capacitance is detected. You may do it.

  According to the first embodiment, a predetermined reference capacitance value Th is stored in the storage unit 11, and information such as identification information ID (data) is transmitted from the first communication electrode 16 a and the second communication electrode 16 b by the transmission unit 15. ) Is transmitted by an electric field, and the stray capacitance C generated between the object and the proximity object is detected by the detection electrode 12, and the value varies depending on the distance between the object and the measurement unit 13. When the value of the detected stray capacitance is measured and the value of the stray capacitance measured by the control unit 14 exceeds the reference value, the transmission of the information (data) is stopped. It is possible to prevent (data) from being erroneously propagated in space. That is, it is possible to control communication with an undesired person B who has come close to the electric field communication device, and to control the spatial propagation distance of the electric field signal.

  The stray capacitance described in the first embodiment is not only between the portable electric field communication device 1 with a stray capacitance sensor possessed by the holder A and the other person B, but also with the portable electric field communication device 1 with the stray capacitance sensor and the owner. It also occurs between A. Therefore, the portable electric field communication device 1 with a stray capacitance sensor according to the second embodiment detects each stray capacitance with two detection electrodes arranged opposite to each other, and based on the result of comparing the detected stray capacitance values. It is characterized by controlling transmission of information (data) such as identification information ID.

  FIG. 4 is a diagram illustrating a functional block configuration of the portable electric field communication device with a stray capacitance sensor according to the second embodiment. This portable electric field communication device 1 with a stray capacitance sensor has a first common electrode 17a and a second common electrode 17a instead of the first communication electrode 16a and the second communication electrode 16b and the detection electrode 12 used in the first embodiment. Common electrode 17b, and other functional units are the same as in the first embodiment. Hereinafter, configurations, functions, and processing operations different from those in the first embodiment will be described.

  The first common electrode 17a realizes both the functions of the detection electrode 12 and the first communication electrode 16a used in the first embodiment, and forms the outer shape of the portable electric field communication device with a floating capacitance sensor 1. It is placed on one surface of the body.

  The second common electrode 17b realizes both functions of the detection electrode 12 and the second communication electrode 16b used in the first embodiment, and is arranged on one surface of the casing so as to face the first common electrode 17a. Has been.

  The measurement unit 13 has a function of measuring the value of the stray capacitance detected by the first common electrode 17a and measuring the value of the stray capacitance detected by the second common electrode 17b.

  The control unit 14 has a function of comparing the values of the stray capacitances measured by the measurement unit 13 and controlling the transmission processing of the transmission unit 15 based on the comparison result.

  The transmission unit 15 induces an electric field in the electric field transmission medium from the first common electrode 17a and the second common electrode 17b arranged to face the surface of the casing, and polarizes the information stored in the storage unit 11 in advance. A signal having a positive polarity is output from the first common electrode 17a, a signal having a negative polarity is output from the second common electrode 17b, and transmitted to another electric field communication device for transmission. have.

  Next, the operation of the portable electric field communication device 1 with a stray capacitance sensor according to the second embodiment will be described. FIG. 5 is a diagram for explaining the processing operation of the portable electric field communication device 1 with the stray capacitance sensor according to the second embodiment. FIG. 6 is a diagram illustrating a processing flow of the portable electric field communication device 1 with the stray capacitance sensor according to the second embodiment.

  Here, when the holder A holds the second common electrode 17b inside (body side), the stray capacitance C2 is generated between the holder A and the second common electrode 17b. Further, since the distance from the portable electric field communication device 1 with the stray capacitance sensor is much shorter than the distance from the other person B, the stray capacitance C1 is also present between the owner A and the first common electrode 17a. appear. Further, when another person B who is not the owner of the portable electric field communication device 1 with a stray capacitance sensor comes close to the owner A, a stray capacitance C is generated between the first common electrode 17a and the other person B. To do. Note that stray capacitance between the second common electrode 17b and another person B is ignored.

  Therefore, first, the stray capacitance C generated between the first common electrode 17a and the other person B by the first common electrode 17a and the stray capacitance generated between the first common electrode 17a and the holder A are first obtained. C1 is detected (S11), and the measurement unit 13 measures the value C ′ of the stray capacitance detected in S11 (S12).

  Further, the stray capacitance C2 generated between the second common electrode 17b and the holder A is detected by the second common electrode 17b (S13), and the measurement unit 13 detects the stray capacitance value C detected in S13. '' Is measured (S14). S11 to S14 may be processed at the same time, or S13 and S14 may be processed before S11 and S12.

  Next, the control unit 14 compares the value of the stray capacitance C ′ measured in S12 with the value of the stray capacitance C ″ measured in S14 (S15).

  Next, when the value of the stray capacitance C ″ is larger than the value of the stray capacitance C ′, the control unit 14 places the second common electrode 17b on the body side of the owner A (the back side for the owner), It is determined that the first common electrode 17a is disposed outside the holder A (front side for the holder) (S16). That is, the front and back of the portable electric field communication device 1 with the stray capacitance sensor for the holder A is determined.

  Next, the detection electrode that should detect the stray capacitance generated with another person B from the front / back discrimination result in S16 by the control unit 14 may be the first common electrode 17a that has detected a small stray capacitance value. It is specified (S17).

  Next, the control unit 14 reads a predetermined reference capacitance value Th from the storage unit 11, and the magnitude of the reference capacitance value Th and the value of the stray capacitance detected by the first common electrode 17a specified in S17. Are compared (S18).

  Next, when the value of the stray capacitance detected as a result of the comparison in S18 exceeds the reference capacitance value Th, the control unit 14 stops the output of the positive signal from the first common electrode 17a ( S19).

  The reason why the value of the stray capacitance is compared with the reference capacitance value in S18 is that when the value of the stray capacitance is extremely small, the other person B exists far away from the owner A and the signal from the first common electrode 17a. This is because it is not necessary to stop the output. In addition, since the portable electric field communication device 1 with a stray capacitance sensor does not include a grounding electrode, equivalent signals are transmitted from the first common electrode 17a and the second common electrode 17b.

  According to the second embodiment, the detection electrode and the communication electrode are configured by the same common electrode, and the common electrode is two common electrodes facing each other. The control unit 14 detects the stray capacitance detected by one common electrode. When the value is larger than the value of the stray capacitance detected by the other common electrode, the transmission of information (data) transmitted from the other common electrode is stopped. Thus, it is possible to prevent the propagation in space more reliably.

  Finally, it is of course possible to realize both the first and second embodiments together.

DESCRIPTION OF SYMBOLS 1 ... Portable electric field communication apparatus with a stray capacitance sensor 11 ... Memory | storage part 12 ... Detection electrode 13 ... Measurement part 14 ... Control part 15 ... Transmission part 16a ... 1st communication electrode 16b ... 2nd communication electrode 17a ... 1st Common electrode 17b ... 2nd common electrode 3 ... Area electrode 5 ... Electric field communication device for authentication A ... Owner B ... Others C, C1, C2, C ', C''... Stray capacitance S1-S5, S11-S19 ... Step

Claims (4)

In the portable electric field communication device with a stray capacitance sensor capable of inducing electric field from the communication electrode to the electric field transmission medium and performing electric field communication,
Storage means for storing a constant reference value;
Transmitting means for transmitting predetermined information from the communication electrode by an electric field;
A sensing electrode that detects a stray capacitance that occurs between a nearby object and changes in value according to the size of the distance to the object;
Measuring means for measuring the value of the detected stray capacitance;
Control means for stopping transmission of the predetermined information when the value of the measured stray capacitance exceeds the reference value;
A portable electric field communication device with a stray capacitance sensor. The detection electrode and the communication electrode are composed of the same electrode, and the electrode is two electrodes facing each other,
The control means includes
The transmission of the predetermined information transmitted from the other electrode is stopped when the value of the stray capacitance detected by one electrode is larger than the value of the stray capacitance detected by the other electrode. Item 2. A portable electric field communication device with a stray capacitance sensor according to Item 1. In an electric field communication method of processing with a portable electric field communication device with a stray capacitance sensor capable of performing electric field communication by inducing an electric field from a communication electrode into an electric field transmission medium,
A first step of storing a constant reference value in the storage means;
A second step of transmitting predetermined information from the communication electrode by an electric field;
A third step of detecting, with a detection electrode, a stray capacitance that occurs between a nearby object and changes in value according to the magnitude of the distance to the object;
A fourth step of measuring the value of the detected stray capacitance;
A fifth step of stopping transmission of the predetermined information when the measured value of the stray capacitance exceeds the reference value;
An electric field communication method characterized by comprising: The detection electrode and the communication electrode are composed of the same electrode, and the electrode is two electrodes facing each other,
The fifth step includes
The transmission of the predetermined information transmitted from the other electrode is stopped when the value of the stray capacitance detected by one electrode is larger than the value of the stray capacitance detected by the other electrode. Item 4. The electric field communication method according to Item 3.

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