JP2009030262A - Human body approach detection device - Google Patents

Abstract

Even when radio waves are transmitted / received by a transmission / reception antenna, it is possible to effectively prevent malfunctions, which can be configured at low cost, and do not require complicated preprocessing. I will provide a.
A human body approach detection device is provided in the vicinity of a wall surface 6a on the door 2 inside a housing 6 of a door handle 4 for a vehicle, and a sensor electrode 11 whose capacitance changes as a human body approaches, and a housing 6, first shield electrodes 12 a and 12 b and a second shield that suppress a change in capacitance due to a change in the external environment of the sensor electrode 11 and suppress the influence of radio waves on the main circuit unit 20 of the transmission / reception antenna 19. And an auxiliary electrode composed of electrodes 13a and 13b. The first shield electrodes 12a and 12b are given the same potential as the sensor electrode 11, and the second shield electrodes 13a and 13b are given a ground potential.
[Selection] Figure 2

Description

  INDUSTRIAL APPLICABILITY The present invention is used in a system for controlling the locking and unlocking of doors provided in a vehicle such as an automobile or a facility such as a building, and the approach of a human body to door handles provided in these doors. The present invention relates to a human body approach detection device.

  Conventionally, as a system for controlling the operation of locking and unlocking a door provided in a facility such as a door or a building provided in a vehicle such as an automobile, it has been provided in a vehicle door as shown in FIG. 9, for example. A sensor electrode 31 is provided in the vicinity of the inner wall of the door 30 in the housing 30 of the vehicle door handle. When a human body contacts the wall of the door of the vehicle door handle, a change in capacitance is detected to lock and unlock the vehicle. Those are known (for example, see Patent Document 1).

  In the conventional system of this type, the frame (body) of the vehicle body is normally electrically grounded, and the capacitance formed by the vehicle body door 32 and the sensor electrode 31 in the housing 30 of the door handle. As a reference, it is possible to determine the approach of a person to the door handle.

  That is, in this type of system, when a human hand enters between the door 32 and the sensor electrode 31 and a capacitance is formed by the sensor electrode 31 and the human body, the electrostatic capacitance detected by the sensor electrode 31 is detected. Since the capacitance changes, the approach of the person to the vehicle door handle is detected by this capacitance change.

Paragraph [0022] of JP-A-2002-295064

  However, in the conventional system for controlling the locking and unlocking operation of the vehicle door as described above, for example, when there is a transmission / reception antenna used in the keyless entry system of the automobile near the sensor electrode 31, the transmission / reception is performed. Since there is a capacitive coupling between the antenna for sensor and the sensor electrode 31, when a radio wave is generated from the antenna for transmission / reception, the capacitance between the antenna for transmission / reception and the sensor electrode 31 changes due to the influence, and the human body There is a problem that it is mistakenly detected as being close. Further, when a transmitting / receiving antenna of another vehicle different from the own vehicle approaches, there is a problem that a malfunction occurs similarly.

  Such a problem is caused by storing various capacitance changes such as when a human body approaches or when a radio wave is generated from a transmission / reception antenna as a signal pattern in a control device and the like, However, there is a problem that a large amount of data processing and a storage device are required, the entire system becomes expensive and the processing becomes complicated.

  The present invention has been made in view of such problems. Even when radio waves are transmitted / received by a transmitting / receiving antenna, it is possible to effectively prevent malfunctions and to reduce the cost. It is an object of the present invention to provide a human body approaching detection device that can be configured in a simple manner and can eliminate complicated preprocessing.

  In order to solve the above-described problems and achieve the object, a human body approach detection device according to the present invention is provided in the vicinity of a door side wall surface inside a housing of a door handle attached to a door, and electrostatically moves when the human body approaches. A sensor electrode whose capacitance changes, an auxiliary electrode which is provided inside the housing and suppresses a change in capacitance due to a change in the external environment of the sensor electrode, and a capacitance which is provided inside the housing and which is provided inside the housing. A detection circuit for detecting a change, and a transmission / reception antenna for an authentication transmission / reception key used in a keyless entry system, provided near a wall surface opposite to the door inside the housing, and the auxiliary electrode includes the auxiliary electrode, It is arranged inside the housing in a state of being interposed between a detection circuit and the transmitting / receiving antenna.

  The human body approach detection device according to the present invention is configured as described above, and this transmission / reception antenna and detection circuit can be used even when radio waves are transmitted / received by the transmission / reception antenna provided in the housing of the door handle. The auxiliary electrode interposed between them suppresses, for example, the capacitance change of the sensor electrode and the influence of the radio wave applied to the detection circuit, so that it is possible to effectively prevent malfunction. Further, the human body approach detection device according to the present invention is provided only with the auxiliary electrode, and does not require a large amount of data processing or a storage device.

  The auxiliary electrode may be arranged inside the housing so as not to exert an influence of radio waves from the transmitting / receiving antenna on at least the detection circuit.

  The auxiliary electrode may be configured to be supplied with a ground potential or a potential equivalent to the sensor electrode. Note that the potential equivalent to the sensor electrode here is a potential that is the same as or close to that of the sensor electrode and has a very small capacitance coupling with the sensor electrode.

  In addition, the auxiliary electrode includes a first shield electrode provided in the housing at a position between the sensor electrode and the door, and provided with a ground potential or a potential equivalent to the sensor electrode. May be.

  The first shield electrode is provided near the side wall surface of the door inside the housing, and is disposed so as to surround the sensor electrode, and at least a part of the detection circuit and the door are opposite to each other. The ground potential or the same potential as that of the sensor electrode may be applied.

  The first shield electrode is further provided between the sensor electrode and the wall surface on the opposite side of the door inside the housing, and is applied with the ground potential or the same potential as the sensor electrode. It may be configured.

  The auxiliary electrode is provided between a wall surface of the housing opposite to the door and the sensor electrode and the detection circuit, and is supplied with a ground potential or a potential equivalent to the sensor electrode. You may be set as the structure containing 2 shield electrodes.

  The second shield electrode is provided between the first shield electrode and a wall surface on the opposite side of the door inside the housing, and is applied with a ground potential or a potential equivalent to the sensor electrode. It may be configured to be.

  Further, the second shield electrode is disposed around at least a part of the detection circuit and at least a part of the detection circuit between the wall surface on the side opposite to the door. Further, a configuration may be adopted in which a ground potential or a potential equivalent to that of the sensor electrode is applied.

  The sensor electrode and the auxiliary electrode may be formed of the same flexible printed circuit, and the detection circuit may be mounted on the flexible printed circuit.

  Further, a groove may be formed in at least one of the sensor electrode and the auxiliary electrode.

  In addition, a light emitting body that is provided in the housing and emits light when a capacitance is detected by the sensor electrode is further provided, and at least a part of the housing is formed of a translucent material. Also good.

  As described above, according to the present invention, it is possible to effectively prevent malfunction even when radio waves are transmitted / received by a transmitting / receiving antenna, and at the same time, it can be configured at a low cost and is complicated. It is possible to provide a human body approach detection device that can eliminate processing.

  Hereinafter, preferred embodiments of a human body approach detection device according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a plan view showing an example of a vehicle door handle of an automobile on which a human body approaching detection apparatus according to an embodiment of the present invention is mounted, FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. It is BB 'sectional drawing of FIG. 4 is a plan view showing an example of the entire configuration of the human body approach detection device, FIG. 5 is a perspective view showing an example of the entire configuration of the human body approach detection device, and FIG. 6 is an electric diagram of the human body approach detection device. It is a circuit diagram which shows the example of a general schematic structure. The human body approach detection device according to this embodiment is used in, for example, a system that controls locking and unlocking of a vehicle door of an automobile, and detects the approach of a human body to a vehicle door handle provided on the vehicle door. Is.

  The human body approach detection device is mainly configured to include a sensor unit 10 and a main circuit unit 20. The sensor unit 10 includes a rectangular sensor electrode 11 extending in a longitudinal direction (a direction orthogonal to the paper surface of FIGS. 2 and 3) along a wall surface 6 a on the door 2 side of the housing 6 constituting the vehicle door handle 4. ing.

  Similarly, the sensor unit 10 is provided inside the wall surface 6a so as to surround the sensor electrode 11 (see FIG. 2), and at least a part of the main circuit unit 20 described later and the door 2 are First shield electrodes 12a and 12b are provided so as to face each other between the opposite wall surface 6b (see FIG. 3). In the sensor unit 10, the first shield electrode 12a is also provided between the wall surface 6b and the sensor electrode 11 (see FIG. 2).

  Furthermore, the sensor unit 10 is provided between the wall surface 6b, the sensor electrode 11, and the main circuit unit 20 (see FIGS. 2 and 3), and between at least a part of the main circuit unit 20 and the wall surface 6b. The second shield electrodes 13a and 13b are provided so as to surround the first shield electrode 12b disposed opposite to at least a part of the main circuit portion 20 (see FIG. 3).

  Specifically, the second shield electrode 13a is disposed between the wall surface 6b and the first shield electrodes 12a and 12b. The first shield electrodes 12a and 12b and the second shield electrodes 13a and 13b are arranged in a state of being interposed between the sensor electrode 11 and the main circuit unit 20 in the housing 6 and a transmitting / receiving antenna 19 described later. While constituting the auxiliary electrode with respect to the sensor electrode 11, it plays the role of the shield electrode with respect to the main circuit part 20. FIG.

  As shown in FIGS. 4 and 5, the sensor unit 10 configured as described above includes, for example, a single flexible printed circuit (FPC), and includes the sensor electrode 11, the first shield electrodes 12 a and 12 b, and the first The two shield electrodes 13a and 13b were patterned on an insulating plate 14 made of various insulators such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyamide (PA) or epoxy resin. It is comprised from various conductors, such as copper, copper alloy, or aluminum.

  As shown in FIG. 4, the sensor electrode 11 is partly formed in a rectangular shape connected to the main circuit portion 20, and the first shield electrode 12 a is located in the vicinity of the position where the sensor electrode 11 is formed on the insulating plate 14. Is formed in a deformed square shape surrounding the sensor electrode 11 (a square shape that is not partially connected), and is formed in a rectangular shape on the opposite side of the sensor electrode 11. Further, the first shield electrode 12b is formed in a square shape on the opposite side of the main circuit portion 20.

  The second shield electrode 13a is disposed near the first shield electrodes 12a and 12b on the insulating plate 14 on the opposite side of the sensor electrode 11 and the main circuit portion 20, with the insulating plate 14 interposed therebetween. Is formed in a rectangular shape on the opposite surface. The second shield electrode 13b is formed in a square shape surrounding the first shield electrode 12b in the vicinity of the location where the first shield electrode 12b is formed.

  As shown in FIG. 6, for example, the first shield electrodes 12a and 12b are given a potential equal to that of the sensor electrode 11, and the second shield electrodes 13a and 13b are given a ground potential. As shown in FIG. 4, the human body approaching detection device is assembled by folding the sensor unit 10 formed in the arrow direction as shown in FIG. 4, and is housed in the housing 6 of the vehicle door handle 4.

  The transmission / reception antenna 19 for the authentication transmission / reception key of the keyless entry system is disposed in the space between the sensor electrode 11 and the wall surface 6 b in the housing 6 of the vehicle door handle 4. Specifically, the transmission / reception antenna 19 is made of, for example, a rectangular bar-shaped metal member extending along the sensor electrode 11, and is disposed in a space between the wall surface 6b in the housing 6 and the second shield electrode 13a.

  The first shield electrodes 12a and 12b closest to the main circuit unit 20 are given the same potential as the sensor electrode 11, and the second shield electrodes 13a and 13b are the transmission / reception antenna 19 and the first shield electrodes 12a and 12b. The ground potential is applied between the main circuit unit 20 and the ground to prevent the sensor sensitivity to the human body from being lowered due to the dominant coupling between the main circuit unit 20 and the ground. It is.

  Therefore, when only the first shield electrodes 12a and 12b are arranged, for example, a ground potential may be given to them. Although the human body approach detection device of this example is configured by FPC, it may be configured by using, for example, a metal or a rigid printed circuit board, a rigid-flexible circuit board, an electric wire, or a membrane.

  On the other hand, as shown in FIG. 6, the main circuit unit 20 is configured as follows, for example. That is, the sensor electrode 11 is connected to the input end of the detection circuit 23 of the main circuit unit 20. The sensor electrode 11 is connected to one input end of a buffer 21 made of an operational amplifier. The first shield electrodes 12a and 12b are connected to the other input end of the buffer 21 and to the output end.

  The buffer 21 keeps the sensor electrode 11 and the first shield electrodes 12a and 12b in a high impedance state, and prevents charging and discharging between them at the same potential. An output signal from the sensor electrode 11 is input to the detection circuit 23. The detection circuit 23 outputs a pulse signal whose frequency or duty ratio changes in accordance with the electrostatic capacitance between the sensor electrode 11 and the second shield electrodes 13a and 13b, the door 2, and the close human body regarded as the ground. .

  This pulse signal is input to a low-pass filter (LPF) 24. The LPF 24 smoothes the pulse signal from the detection circuit 23 and outputs a detection signal. The control circuit 25 receives the detection signal from the LPF 24 and outputs a switch to an external electric circuit according to the signal level.

  FIG. 7 is a circuit diagram illustrating an example of the configuration of the detection circuit 23 in which the duty ratio changes according to the capacitance C. The detection circuit 23 includes, for example, a trigger signal generation circuit 231 that outputs a trigger signal TG having a constant period, and a timer circuit that outputs a pulse signal Po whose duty ratio changes depending on the magnitude of the capacitance C connected to the input end. 232.

  The timer circuit 232 includes, for example, two comparators 2321 and 2322 and an RS flip-flop circuit (hereinafter referred to as “RS-FF”) in which outputs of the comparators 2321 and 2322 are input to the reset terminal R and the set terminal S, respectively. ) 2323, a buffer 2324 that outputs the output DIS (discharge signal) of the RS-FF 2323 to the LPF 24, and a transistor 2325 that is ON / OFF controlled by the output DIS of the RS-FF 2323.

  The comparator 2322 compares the trigger signal TG as shown in FIG. 8 output from the trigger signal generation circuit 231 with a predetermined threshold Vth2 divided by the resistors R1, R2, and R3, and is synchronized with the trigger signal TG. Set pulse is output. This set pulse sets the Q output of RS-FF 2323.

  The Q output turns off the transistor 2325 as the discharge signal DIS, and the resistor R4 connected between the sensor electrode 11 and the ground, and between the ground capacitance C of the sensor electrode 11 and the input terminal and the power supply line. Charge at a speed determined by the time constant. As a result, as shown in FIG. 8, the potential of the input signal Vin increases at a speed determined by the capacitance.

  When the input signal Vin exceeds the threshold value Vth1 determined by the resistors R1, R2, and R3, the output of the comparator 2321 is inverted and the output of the RS-FF 2323 is inverted. As a result, the transistor 2325 is turned on, and the charge accumulated in the sensor electrode 11 is discharged through the transistor 2325.

  Therefore, the timer circuit 232 outputs a pulse signal Po that oscillates at a duty ratio based on the capacitance between the sensor electrode 11 and the second shield electrodes 13a and 13b, as shown in FIG. The LPF 24 smoothes this output to output a DC detection signal Vout as shown in FIG.

  In FIG. 8, the waveform indicated by the solid line and the waveform indicated by the dotted line indicate that the former has a smaller capacitance than the latter. In the human body approach detection device according to the present embodiment, for example, when a human hand approaches the sensor region of the sensor electrode 11 on the wall surface 6a on the door 2 side of the housing 6 of the vehicle door handle 4, the sensor electrode 11 and the In addition to the capacitance between the two shield electrodes 13a and 13b and the door 2, capacitive coupling with the human body as the ground with respect to the sensor electrode 11 occurs.

  For this reason, the electrostatic capacitance between the detected sensor electrode 11 and the ground increases. Therefore, the waveform shown by the dotted line in FIG. 8 indicates the proximity state of the human body. When the human hand touches the entire sensor region of the sensor electrode 11 on the wall surface 6a on the door 2 side of the housing 6 of the vehicle door handle 4, the sensor electrode 11 and the ground are detected. The capacitance between and reaches a maximum value.

  The human body approaching detection apparatus according to the present embodiment is triggered by the time when the electrostatic capacity reaches an arbitrary threshold value between the electrostatic capacity when there is no human hand and the maximum value. It is configured to lock and unlock. This threshold value may be determined by calculating an appropriate value from the amount of increase in electrostatic capacitance caused by how the human body is applied to the vehicle door handle 4 and set in the human body approach detection device. .

  In the human body approach detection device according to the present embodiment, first shield electrodes 12a having the same potential as sensor electrode 11 are provided around sensor electrode 11 in housing 6 and at a facing position, and at a position facing main circuit portion 20. A first shield electrode 12b having the same potential is provided. Further, the second shield electrode 13a having the ground potential is provided between the first shield electrodes 12a and 12b and the transmitting / receiving antenna 19, and the second shield electrode 13b having the same potential is provided around the first shield electrode 12b. Yes.

  That is, the first shield electrodes 12a and 12b having the same potential as the sensor electrode 11 are disposed at positions close to the sensor electrode 11 and the main circuit section 20, and the second shield having the ground potential is disposed at a position close to the transmission / reception antenna 19. Electrodes 13a and 13b are arranged. For this reason, since the electrostatic capacitance between the sensor electrode 11 and the transmitting / receiving antenna 19 decreases, the detection sensitivity of the approaching human body without being affected by the capacitance change due to the transmission / reception of radio waves by the transmitting / receiving antenna 19 as much as possible. Thus, even when radio waves are transmitted / received by the transmission / reception antenna 19, it is possible to effectively prevent malfunctions.

  Such an effect of the human body approach detection device of this example is also effective when radio waves are transmitted / received by a transmission / reception antenna of another vehicle in the vicinity of the own vehicle. Further, by adopting such a configuration, the entire human body approaching detection apparatus can be configured at low cost, and complicated preprocessing such as data processing can be eliminated.

  In the human body approach detection device according to the above-described embodiment, the first shield electrode 12a is not necessarily provided on the same surface as the sensor electrode 11 in the insulating plate 14, and the housing 2 has the door 2 side. As long as the potential equivalent to that of the sensor electrode 11 is generated around the corresponding position of the sensor electrode 11 on the wall surface 6a, the surface 6a may be provided on a different plane.

  Further, the periphery of the position corresponding to the sensor electrode 11 is not only the vicinity of the sensor electrode 11 but also the sensor electrode through the housing 6 of the vehicle door handle 4 such as a connection portion between the vehicle door handle 4 and the door 2. The spatial position between 11 and the door 2 is also included. Since the basic structure of the keyless entry system is described in Patent Document 1 described above, description thereof is omitted here.

  Although not shown, in the human body approach detection device described above, for example, grooves extending in the longitudinal direction are formed in each of the sensor electrode 11, the first shield electrodes 12a and 12b, and the second shield electrodes 13a and 13b. May be. This groove is formed, for example, by turning back a pattern extending in the longitudinal direction of each electrode 11, 12a, 12b, 13a, 13b in the longitudinal direction, and the width of each groove is set to each electrode 11, 12a, 12b, 13a, 13b. The width of the pattern extending in the longitudinal direction may be the same as or shorter than that of the pattern.

  That is, the transmission / reception antenna 19 has a structure in which a wire is wound around a ferrite generally called a bar antenna, and is driven by forming a series resonance circuit with a capacitor. An eddy current is generated from a part or all of 11, 12a, 12b, 13a, and 13b, and as a result, the output from the transmission / reception antenna 19 is reduced, or the resonance frequency of the circuit is changed by the impedance and the characteristics are deteriorated. May end up.

  However, by providing the grooves 11, 12a, 12b, 13a, 13b as described above, eddy currents generated from the electrodes 11, 12a, 12b, 13a, 13b can be reduced. Further, by forming the groove width equal to or shorter than the width of the pattern extending in the longitudinal direction of each electrode 11, 12a, 12b, 13a, 13b, the potential of each groove becomes the same as the surrounding, It can prevent that the effect of 11, 12a, 12b, 13a, 13b reduces. Such grooves need not be formed in all of the electrodes 11, 12a, 12b, 13a, 13b, and the pattern may not be folded but may be formed in a comb-teeth shape extending in the longitudinal direction. .

  In the human body approach detection device described above, an oscillation circuit used in the keyless entry system may be included in the main circuit portion 20 and formed on the insulating plate 14 of the FPC. In addition, a light emitter such as LED or EL is provided, and the light emitter such as LED or EL is caused to emit light when detecting the capacitance that triggers the locking and unlocking of the door 2 of the automobile. Also good.

  In this case, at least a part of the housing 6 of the vehicle door handle 4, that is, a part where light is to be emitted to the outside needs to be formed of a translucent member. Further, when the sensor electrode 11 or the like is disposed in this portion, a light-transmitting material is used as the insulating plate 14, and the sensor electrode 11 or the like is applied by applying a light-transmitting conductive material on the insulating plate 14. The pattern may be formed. As the light-transmitting conductive material, for example, ITO (indium tin oxide), ZnO (zinc oxide), conductive polymer (PEDOT / PSS), or the like may be used.

  The human body approach detection device described above uses a known timer circuit (timer IC) in which the duty ratio of the output pulse changes depending on the time constant of the resistor and the capacitor as the detection circuit 23 for detecting the capacitance. However, the present invention is not limited to this. For example, a method of directly measuring impedance, a method of measuring an oscillation frequency by configuring an oscillation circuit, and a method of measuring a charge / discharge time by configuring an RC charge / discharge circuit Various methods, such as a method of measuring the voltage by moving a charge charged at a known voltage to a known capacity, or a method of measuring the number of times until a predetermined voltage is charged to a known capacity by moving the charge multiple times There is a method, and a threshold is set for the detected capacitance, or the signal waveform of the capacitance is analyzed and the corresponding capacitance waveform is triggered, etc. It may be subjected to various kinds of processing.

  Furthermore, in the human body approach detection device described above, the buffer 21 is configured by the voltage follower of the operational amplifier, and the sensor electrode 11 and the first shield electrodes 12a and 12b are connected via the buffer 21, but such Even if it is not a voltage follower, for example, it is sufficient that the input amplifier has a high input impedance and a low output impedance, and the operational amplifier used at this time preferably has characteristics of high speed (low delay time) and high slew rate. .

  Alternatively, the voltage applied to the sensor electrode 11 may be captured by an A / D converter, the same voltage may be output by the D / A converter, and connected to the first shield electrodes 12a and 12b. The applied voltage from the detection circuit 23 to the sensor electrode 11 is connected to the non-inverting input of the operational amplifier, the inverting input is connected to the sensor electrode 11, and the non-inverting input is directly applied to the first shield electrodes 12a and 12b. You may make it drive by connecting. Needless to say, even if a rectangular wave (digital signal) having the same period as the signal applied to the sensor electrode 11 is applied to the first shield electrodes 12a and 12b, an effect close to the same potential can be obtained.

  As described above, according to the human body approach detection device according to the present embodiment, radio waves are transmitted / received by the transmission / reception antenna 19 provided in the housing 6 of the vehicle door handle 4 or in the vicinity of the own vehicle. Even when radio waves are transmitted / received by a transmission / reception antenna of another vehicle, a change in the capacitance of the sensor electrode 11 is suppressed by the auxiliary electrode including the first shield electrodes 12a and 12b and the second shield electrodes 13a and 13b. .

  For this reason, it is possible to effectively prevent malfunctions at the time of locking and unlocking the door 2 and to prevent malfunctions with a simple configuration of providing auxiliary electrodes. A human body approach detection device can be configured at low cost without requiring a storage device or the like.

  Further, the human body approach detection device described above has been described by taking as an example a case where the device is applied to control locking and unlocking of the door 2 with a vehicle door handle 4 provided in a vehicle such as an automobile. The present invention can be applied in the same manner to control locking and unlocking of doors provided in facilities such as.

It is a top view which shows the example of the vehicle door handle of the motor vehicle by which the human body approach detection apparatus which concerns on one embodiment of this invention is mounted. It is A-A 'sectional drawing of FIG. It is B-B 'sectional drawing of FIG. It is a top view which shows the example of the whole structure of a human body approach detection apparatus. It is a perspective view which shows the example of the whole structure of a human body approach detection apparatus. It is a circuit diagram which shows the example of an electrical schematic structure of a human body approach detection apparatus. It is a circuit diagram which shows the example of a structure of the detection circuit of a human body approach detection apparatus. It is a wave form diagram which shows the example of operation | movement of a human body approach detection apparatus. It is a top view of the vehicle door handle of the motor vehicle by which the conventional human body approach detection apparatus is mounted.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Door, 4 ... Door handle for vehicles, 6 ... Housing, 6a, 6b ... Wall surface, 10 ... Sensor part, 11 ... Sensor electrode, 12a, 12b ... 1st shield electrode, 13a, 13b ... 2nd shield electrode, 14 DESCRIPTION OF SYMBOLS ... Insulating plate, 19 ... Transmission / reception antenna, 20 ... Main circuit part, 21 ... Buffer, 23 ... Detection circuit, 24 ... LPF, 25 ... Control circuit.

Claims (12)

A sensor electrode that is provided in the vicinity of the door side wall surface inside the housing of the door handle attached to the door, and whose capacitance changes as the human body approaches,
An auxiliary electrode that is provided inside the housing and suppresses a change in capacitance due to a change in the external environment of the sensor electrode;
A detection circuit provided inside the housing for detecting a change in capacitance of the sensor electrode;
Provided in the vicinity of the wall on the opposite side of the door inside the housing, including a transmission / reception antenna for an authentication transmission / reception key used in a keyless entry system,
The human body approach detection device, wherein the auxiliary electrode is disposed inside the housing in a state of being interposed between the detection circuit and the transmission / reception antenna.   2. The human body approach detection device according to claim 1, wherein the auxiliary electrode is disposed inside the housing so as not to exert an influence of radio waves by the transmitting / receiving antenna on at least the detection circuit.   The human body approach detection device according to claim 1, wherein the auxiliary electrode is given a ground potential or a potential equivalent to the sensor electrode.   The auxiliary electrode includes a first shield electrode provided in the housing at a position between the sensor electrode and the door, and provided with a ground potential or a potential equivalent to the sensor electrode. The human body approach detection apparatus according to any one of claims 1 to 3.   The first shield electrode is provided in the vicinity of the side wall surface of the door inside the housing, and is disposed so as to surround the sensor electrode, and at least a part of the detection circuit and the wall surface opposite to the door The human body approaching detection apparatus according to claim 4, wherein the human body approaching detection apparatus is disposed so as to face each other and is supplied with a ground potential or a potential equal to the sensor electrode.   The first shield electrode is further provided between the sensor electrode and a wall surface on the opposite side of the door inside the housing, and is provided with a potential equal to the ground potential or the sensor electrode. The human body approach detection device according to claim 5, wherein:   The auxiliary electrode is provided between a wall surface of the housing opposite to the door and the sensor electrode and the detection circuit, and a second shield to which the ground potential or a potential equivalent to the sensor electrode is applied. The human body approach detection device according to claim 3, further comprising an electrode.   The second shield electrode is provided between a wall surface on the opposite side of the door inside the housing and the first shield electrode, and is provided with a potential equal to the ground potential or the sensor electrode. The human body approach detection device according to claim 7.   The second shield electrode surrounds the first shield electrode disposed opposite to at least a part of the detection circuit between at least a part of the detection circuit and a wall surface opposite to the door. The human body approaching detection apparatus according to claim 7, further comprising: a ground potential or a potential equivalent to that of the sensor electrode. The sensor electrode and the auxiliary electrode are formed by the same flexible printed circuit,
The human body approach detection device according to claim 1, wherein the detection circuit is mounted on the flexible printed circuit.   The human body approach detection device according to claim 1, wherein a groove is formed in at least one of the sensor electrode and the auxiliary electrode. A light emitter that is provided in the housing and emits a detection state of capacitance by the sensor electrode;
The human body approaching detection apparatus according to claim 1, wherein at least a part of the housing is formed of a translucent material.

Images