JP2016070052A - Proximity sensor, and keyless entry device comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proximity sensor capable of preventing erroneous detection caused by rain's adherence to a door handle and a keyless entry device comprising the sensor.SOLUTION: A proximity sensor comprises: a circuit board on which a detection circuit is printed; and a first driving electrode and lock electrode that are implemented on one surface of the circuit board and are electrically connected to the detection circuit. The plate-like first driving electrode and lock electrode are erected on one surface of the circuit board so as to face each other; a plate-like second driving electrode and unlock electrode are erected on the other surface of the circuit board so as to face each other. The proximity sensor is used for a keyless entry device for a vehicle. A controller for controlling driving of an actuator for locking or unlocking a vehicle door on the basis of the proximity sensor's detection determines that the proximity sensor has turned ON when an output reduction amount of the proximity sensor exceeds a predetermined threshold.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a proximity sensor that employs a mutual capacitance system and a keyless entry device for a vehicle including the proximity sensor.

  In recent years, when a driver carries an electronic key having a transmission function and a hand approaches or comes into contact with a door handle, the door is automatically unlocked (unlocked) or locked (locked). A keyless entry device as described above is provided. This keyless entry device includes a proximity sensor incorporated in a door handle of a vehicle and an antenna that transmits and receives signals to and from an electronic key when the proximity sensor detects proximity or contact of a human hand with the door handle. And an actuator that locks or unlocks the door of the vehicle, and an ON / OFF of the proximity sensor detected by the output of the proximity sensor, the proximity sensor is turned ON, and the antenna receives a code signal received from the electronic key. And a controller that drives the actuator to lock or unlock the door when the vehicle-specific code signal matches.

  The proximity sensor used in such a keyless entry device detects proximity or contact of a human hand by a capacitance method, and this has been proposed in, for example, Patent Documents 1 and 2 and the like. Yes.

  FIG. 16 shows FIG. 4 of Patent Document 1. In FIG. The proximity sensor described in Patent Document 1 will be described with reference to this figure. The proximity sensor includes a circuit board on which a detection circuit is printed, a drive electrode (reference electrode) and a detection electrode (detection electrode) mounted on the circuit board. Measuring electrode). Here, the drive electrode and the detection electrode are mounted in a plane on the circuit board, and these are electrically connected to the detection circuit.

  When a pulse voltage is applied to the drive electrode of the proximity sensor, an electric field is generated between the drive electrode and the detection electrode. When a human hand approaches or comes into contact with the proximity sensor, a part of electric lines of force flying from the drive electrode toward the detection electrode is absorbed by the human hand that is a dielectric. At this time, the number of lines of electric force reaching the detection electrode is reduced. Therefore, the voltage induced in the detection electrode is reduced. That is, by measuring this voltage drop, it is possible to detect that a human hand has approached or touched the proximity sensor.

  As shown in FIG. 4B of Patent Document 3, the detection electrode of the unlocking sensor is provided on one mounting surface of the circuit board on which the detection circuit is printed, and the locking sensor is provided on the other mounting surface. A proximity sensor provided with the detection electrode is also disclosed.

Special table 2012-500919 gazette International Publication No. 2010/053013 Japanese Patent Laid-Open No. 2003-221948

  By the way, the proximity sensor used in the keyless entry device is incorporated in the door handle of the vehicle, and the door handle is exposed on the outer surface of the vehicle body. Although it may stick to the handle, until now it has not been possible to accurately identify the difference between the dielectric constant of rain and human hands. For this reason, the proximity sensor mistakenly detects that rain has adhered to the door handle when the human hand approaches or touches the door handle, and the keyless entry device malfunctions and the door is unintentionally unlocked or locked. There was a problem that.

  Accordingly, the present invention has been made in view of the above-described problems, and is a proximity sensor that can prevent erroneous detection due to rain adhering to a door handle and locking of a vehicle door due to erroneous detection of the proximity sensor or It is an object of the present invention to provide a keyless entry device that can prevent an unlocking malfunction.

  The present invention proposes the following matters in order to solve the above problems.

  (1) The present invention includes a circuit board on which a detection circuit is printed, one drive electrode mounted on one surface of the circuit board and electrically connected to the detection circuit, one detection electrode, In the proximity sensor comprising: a proximity sensor characterized in that the plate-like drive electrode 1 and the detection electrode 1 are erected on one surface of the circuit board. .

  (2) The proximity of the proximity sensor of (1) is characterized in that the other drive electrode and the other detection electrode in the form of a plate are erected opposite to the other surface of the circuit board. A sensor is proposed.

  (3) The present invention provides a circuit board on which a detection circuit is printed, one drive electrode mounted on one surface of the circuit board and electrically connected to the detection circuit, one detection electrode, In the proximity sensor comprising: a flat plate-like one drive electrode and the one detection electrode, the one drive electrode and the one detection electrode are erected so as to face each other on one surface of the circuit board. A proximity sensor is proposed in which an antenna for transmitting / receiving a signal to / from a portable transmitter when a proximity or contact to the one detection electrode is detected is provided between the antenna and the sensor.

  (4) The present invention relates to the proximity sensor of (3), wherein the other drive electrode and the other detection electrode in the form of a plate are arranged on the same plane on which the antenna of the circuit board is disposed, Proximity sensors are proposed which are erected so as to face each other at a position separated from one detection electrode.

  (5) The present invention relates to a proximity sensor incorporated in a door handle of a vehicle and an antenna that transmits and receives signals to and from a portable transmitter when the proximity sensor detects proximity or contact of a person to the door handle. And an actuator that locks or unlocks the door of the vehicle, and an ON / OFF signal of the proximity sensor detected by the output of the proximity sensor, and the antenna is turned on and the code received by the antenna from the portable transmitter In a keyless entry device comprising: a controller that drives the actuator to lock or unlock the door when a signal and a vehicle-specific code signal match each other, the proximity sensor according to (1) to (4) The proximity sensor is configured by any one of the proximity sensors, and the controller detects the proximity sensor when the output decrease of the proximity sensor exceeds a predetermined threshold value. It proposes a keyless entry device which is characterized in that so as to determine that that turns ON.

  (6) In the keyless entry device according to (5), the controller supplies a driving voltage to the driving electrode and charges a capacitor with a voltage output from the proximity sensor, measures a charging voltage value, and charges The discharge of voltage is repeatedly controlled every predetermined time, the charge voltage value measured this time is compared with the charge voltage value measured last time, and when the difference between the two exceeds a predetermined threshold, the proximity sensor is turned on. The keyless entry device is characterized in that it is determined that the device has been used.

  (7) The present invention is the keyless entry device according to (5) or (6), wherein one of the detection electrode of the first or the other detection electrode constitutes a lock electrode that detects a person's operation when the door is locked, A keyless entry device has been proposed in which the other constitutes an unlock electrode that detects the movement of a person when the door is unlocked.

  In the proximity sensor, if the plate-like drive electrode and the detection electrode are erected on the mounting surface of the circuit board so as to face each other, the inventor can detect the drive electrode and the detection electrode by applying a pulse voltage to the drive electrode. It has been found that the degree to which the number of lines of electric force generated between them decreases due to the proximity of the dielectric (reduction rate) differs depending on whether the dielectric is a human hand or water. More specifically, the degree of decrease in the number of lines of electric force is greater when the dielectric is a human hand than when it is water. Therefore, it has been experimentally found that the voltage induced in the detection electrode is lower when the dielectric is a human hand than when it is water.

  Therefore, the proximity sensor of (1) or (2) outputs a voltage value that is lower when the dielectric is a human hand than when it is water. Therefore, if this proximity sensor is built in the door handle, it is possible to recognize whether the dielectric that approaches or contacts the door handle is a human hand or water.

  Further, according to the keyless entry device of (5) and (6) provided with the proximity sensor of (1) or (2), the output voltage value of the proximity sensor is compared with a predetermined threshold value to Misdetection due to rain can be prevented. Therefore, it is possible to prevent malfunction of locking or unlocking of the vehicle door due to erroneous detection of the proximity sensor.

  According to the proximity sensor of (3), a voltage value that is lower when the dielectric is a human hand than when it is water is output. Therefore, if this proximity sensor is built in the door handle, it is possible to recognize whether the dielectric that approaches or contacts the door handle is a human hand or water. Also, by arranging an antenna between the drive electrode and the unlock electrode (detection electrode) that forms a pair with the drive electrode, the drive electrode, the unlock electrode (detection electrode) that forms a pair with the drive electrode, and the antenna are the same. It can be arranged on a plane. Therefore, there is an effect that the thickness of the proximity sensor can be reduced. Furthermore, by disposing an antenna between the drive electrode and the unlock electrode (detection electrode) paired therewith, the output voltage value of the proximity sensor at normal times becomes high, so noise resistance is improved. Thus, there is an effect that the stability of the operation of the proximity sensor is improved.

  According to the proximity sensor of (4), the unlock electrode (detection electrode), the drive electrode paired therewith, the lock electrode (detection electrode), and the drive electrode paired therewith are arranged on the same plane. Thus, the thickness of the proximity sensor can be reduced. Therefore, there is an effect that it is easy to be built into the door handle.

  Further, according to the keyless entry device of (5) and (6) provided with the proximity sensor of (3) or (4), the output voltage value of the proximity sensor is compared with a predetermined threshold value to Misdetection due to rain can be prevented. Therefore, it is possible to prevent malfunction of locking or unlocking of the vehicle door due to erroneous detection of the proximity sensor. Furthermore, according to the keyless entry devices (5) and (6) provided with the proximity sensor (3) or (4), the thickness of the proximity sensor can be reduced. Therefore, there is an effect that it is easy to be built into the door handle.

  According to the keyless entry device of (7), one of the detection electrodes standing on one side of the circuit board or the other detection electrode standing on the other side of the circuit board is a person when the door is locked. A lock electrode that detects the movement of the hand of the user is configured, and the other is an unlock electrode that detects the movement of the human hand when the door is unlocked. Therefore, by comparing the output voltage value of the proximity sensor with a predetermined threshold value, it is possible to prevent erroneous detection due to rain adhering to the door handle. Therefore, according to the keyless entry device of (5) and (6), it is possible to accurately detect both the driver's intention of locking (locking) and unlocking (unlocking), and the detected driving The door can be automatically locked (locked) or unlocked (unlocked) according to the intention of the person.

It is a side view of a proximity sensor concerning a 1st embodiment of the present invention. It is a top view of a proximity sensor concerning a 1st embodiment of the present invention. It is a bottom view of the proximity sensor which concerns on the 1st Embodiment of this invention. It is a perspective view of a drive electrode and a detection electrode (lock electrode) of the proximity sensor according to the first embodiment of the present invention. It is a perspective view which shows the state which integrated the proximity sensor which concerns on the 1st Embodiment of this invention with the case. It is a block diagram which shows the system configuration | structure of the keyless entry apparatus which concerns on the 1st Embodiment of this invention. 1 is an electric circuit diagram of a keyless entry device according to a first embodiment of the present invention. It is a flowchart which shows the effect | action of the keyless entry apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the experimental data which concern on the 1st Embodiment of this invention. It is a figure which shows the experimental data which concern on the 1st Embodiment of this invention. It is a figure which shows the experimental data which concern on the 1st Embodiment of this invention. It is a figure which shows the experimental data which concern on the 1st Embodiment of this invention. It is a side view of the proximity sensor which concerns on the 2nd Embodiment of this invention. It is a top view of the proximity sensor which concerns on the 2nd Embodiment of this invention. It is a bottom view of the proximity sensor which concerns on the 2nd Embodiment of this invention. It is a top view of the proximity sensor which concerns on related technology.

<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS.

<Configuration of proximity sensor>
The configuration of the proximity sensor according to the present embodiment will be described with reference to FIGS.

  1 is a side view of the proximity sensor according to the present embodiment, FIG. 2 is a plan view of the proximity sensor, FIG. 3 is a bottom view of the proximity sensor, and FIG. 4 is a drive electrode and a detection electrode of the proximity sensor. FIG. 5 is a perspective view showing a state in which the proximity sensor is integrated with a case.

  The proximity sensor 1 according to the present embodiment detects an approach or contact of a person's (driver's) hand by generating an electric field between the electrodes by a mutual capacitance method. 6).

  As shown in FIGS. 1 and 2, the proximity sensor 1 according to the present embodiment is a long and narrow flat circuit board 2 and has one surface (hereinafter referred to as “a wide surface”) having a short length and a wide width. A first drive electrode 3 and a first detection electrode (hereinafter referred to as “lock electrode”) 4 are vertically provided opposite to each other on the “surface”.

  Further, the first drive electrode 3 and the first detection electrode are provided on the other surface (hereinafter referred to as “back surface”) of the narrow and narrow narrow portion 2B integrally extending from the wide portion 2A of the circuit board 2. A second drive electrode 5 and a detection electrode (hereinafter referred to as “unlock electrode”) 6 having a length longer than that of the (lock electrode) 4 are vertically provided opposite to each other.

  A transmission / reception antenna 7 provided in a keyless entry device 10 described later is mounted on the surface of the narrow portion 2B of the circuit board 2. Further, a detection circuit 8 (see FIG. 7) described later is printed on the circuit board 2.

  As shown in FIG. 4, the first drive electrode 3 and the first detection electrode (lock electrode) 4 are bent at both ends in the longitudinal direction of a long and narrow rectangular conductive metal plate such as a copper plate at right angles in opposite directions. The bent portion is soldered to the surface of the wide portion 2 </ b> A of the circuit board 2. As a result, the first drive electrode 3 and the first detection electrode (lock electrode) 4 are erected vertically opposite to the surface of the wide portion 2A of the circuit board 2 as described above.

  Similarly, the second drive electrode 5 and the second detection electrode (unlock electrode) 6 are also formed by bending the longitudinal ends of an elongated rectangular conductive metal plate such as a copper plate at right angles to each other in the opposite direction. The circuit board 2 is soldered to the back surface of the narrow portion 2B. Thus, as described above, the circuit board 2 is vertically provided opposite to the back surface of the narrow portion 2B. The first drive electrode 3 and the second drive electrode 5 are electrically connected to each other by pattern connection.

  In addition, the first drive electrode 3, the second drive electrode 5, the first detection electrode (lock electrode) 4, and the second detection electrode (unlock electrode) 6 are connected to the front surface or the back surface of the circuit board 2. It suffices if they are erected opposite each other. Therefore, the first drive electrode 3, the second drive electrode 5, the first detection electrode (lock electrode) 4, and the second detection electrode (unlock electrode) 6 are in contact with the front surface or the back surface of the circuit board 2. There is no need to stand vertically. For example, an experiment was performed to ensure that the horizontal minimum distance between the opposing electrodes is a predetermined distance or more without causing the opposing electrodes to completely overlap, and that the area of the projected opposing portion is also a predetermined area or more. The angle may be given according to the issued conditions.

  The proximity sensor 1 configured as described above is housed in a thin case 9 shown in FIG. 5 and integrated with the case 9 by resin potting or low-pressure resin mold, and the door handle (not shown) of the vehicle is shown. It is assembled with the case 9 inside. In the proximity sensor 1, the first drive electrode 3 and the first detection electrode (lock electrode) 4 face the outer surface of the door handle, and the second drive electrode 5 and the second detection electrode (unlock electrode). ) 6 is assembled in the door handle so that it faces the inner surface of the door handle.

<Configuration and processing of keyless entry device>
The keyless entry device according to the present embodiment will be described with reference to FIGS.

  6 is a block diagram showing the system configuration of the keyless entry device according to the present invention, FIG. 7 is an electric circuit diagram of the keyless entry device, and FIG. 8 is a flowchart showing the operation of the keyless entry device. .

<Configuration of keyless entry device>
The keyless entry device 10 according to the present embodiment carries an electronic key 11 (see FIG. 6), which is a portable transmitter, by a person (hereinafter referred to as a “driver”) and holds it on a door handle of a vehicle (not shown). The door of the vehicle is automatically unlocked (unlocked) or locked (locked) by bringing them closer to or in contact with each other.

  As shown in FIG. 6, the keyless entry device 10 according to the present embodiment includes a proximity sensor 1 incorporated in a door handle of a vehicle (not shown), and the proximity sensor 1 approaches or contacts the door handle of the driver's hand. Is detected by the antenna 7, the detection circuit 8, the actuator 12 such as a latch device that locks or unlocks the door of the vehicle, and the proximity sensor 1 according to the output of the proximity sensor 1. The first controller (keyless ECU) 13 for detecting the ON / OFF state of the actuator and controlling the drive of the actuator 12 is included.

  Here, the proximity sensor 1 includes the first drive electrode 3, the first detection electrode (lock electrode) 4, and the second drive electrode mounted on the circuit board 2 (see FIGS. 1 to 3) as described above. 5 and an electrode portion 1A including a second detection electrode (unlock electrode) 6.

  The detection circuit 8 includes a second controller (microcomputer) 18, and as shown in FIG. 7, an operational amplifier provided in a path connecting the first detection electrode (lock electrode) 4 and the second controller 18. 14, a diode 15, and an operational amplifier 16 and a diode 17 provided in a path connecting the second detection electrode (unlock electrode) 6 and the second controller 18.

  Note that a capacitor C1 for charging and a resistor R1 for discharging are provided in a path connecting the first detection electrode (lock electrode) 4 and the second controller 18, and the second detection electrode (unlock). In the path connecting the electrode 6 to the first controller 13, a charging capacitor C2 and a discharging resistor R2 are provided.

  Incidentally, the second controller 18 has a function of applying a pulse voltage to the first drive electrode 3 and the second drive electrode 5 of the proximity sensor 1 and a function of detecting ON / OFF of the proximity sensor 1. Yes. The second controller 18 is connected to a DC power source Vcc and is connected to the first controller 13 by a communication line. The second controller 18 has a function of detecting ON of the proximity sensor 1 and transmitting a request signal from the antenna 7 to the electronic key 11.

  On the other hand, the first controller 13 compares the code signal returned from the electronic key 11 to the antenna 7 with respect to the request signal and the code signal unique to the vehicle, and the actuator 12 when the two code signals match. To drive (lock) or unlock (unlock) the door of the vehicle.

  Although not shown, the second controller 18 includes an oscillator that generates a pulse voltage, a timer that measures the oscillation time of the oscillator, a memory that stores the measured voltage value, and the like.

<Processing of keyless entry device>
The processing (processing by the first controller 13 and the second controller 18) of the keyless entry device 10 according to the present embodiment will be described using the flowchart shown in FIG.

  First, when the keyless entry device 10 is operated, a pulse voltage having a predetermined frequency (for example, 125 kHz) is applied from the second controller 18 to the first drive electrode 3 and the second drive electrode 5 of the proximity sensor 1. (Step S1 in FIG. 8).

  Then, an electric field is generated between the first drive electrode 3 and the first detection electrode (lock electrode) 4 and between the second drive electrode 5 and the second detection electrode (unlock electrode) 6. Electric lines of force are generated from the first drive electrode 3 toward the first detection electrode (lock electrode) 4 (see FIG. 4). Similarly, electric lines of force are generated from the second drive electrode 5 toward the second detection electrode (unlock electrode) 6. For this reason, a voltage is induced in the first detection electrode (lock electrode) 4 and the second detection electrode (unlock electrode) 6. The voltages induced in the first detection electrode (lock electrode) 4 and the second detection electrode (unlock electrode) 6 are amplified by the operational amplifiers 14 and 16 of the detection circuit 8 to charge the capacitors C1 and C2, respectively. (Step S2). Note that the application of the pulse voltage to the first drive electrode 3 and the second drive electrode 5 may be performed simultaneously on the first drive electrode 3 and the second drive electrode 5, and individually according to the situation. You may go to

  And, for example, when the driver opens the door in the locked state to get into the parked vehicle, if the driver inserts the hand inside the door handle (not shown), the driver enters the door handle (not shown). Part of the electric lines of force generated from the second drive electrode 5 of the built-in proximity sensor 1 toward the second detection electrode (unlock electrode) 6 is absorbed by the driver's hand, which is a dielectric. Therefore, the number of generated lines of electric force decreases, and the voltage induced in the second detection electrode (unlock electrode) 6 decreases. As a result, the charge (voltage) charged in the capacitor C2 also decreases.

  Also, when the driver gets out of the vehicle, closes the door, and puts his hand close to or in contact with the door handle (not shown) to lock the unlocked door, it is incorporated into the door handle (not shown). Since part of the electric lines of force generated from the first drive electrode 3 of the proximity sensor 1 toward the first detection electrode (lock electrode) 4 is absorbed by the driver's hand as a dielectric, the electric force The number of lines decreases and the voltage induced in the lock electrode 4 decreases. As a result, the charge (voltage) charged in the capacitor C1 also decreases.

  The application of the pulse voltage and the charging of the capacitors C1 and C2 are performed for a predetermined time. That is, the second controller 18 determines whether or not the time measured by the built-in timer has passed a predetermined time (step S3), and when the predetermined time has not passed (step S3: No). The above processing (oscillation and charging) is repeated, and when a predetermined time has elapsed (step S3: Yes), the application of the pulse voltage is stopped (step S4).

  Thereafter, the voltage values of the charged capacitors C1 and C2 are measured (step S5), and the measured voltage values are stored in the memory (step S6). Then, the voltage value measured this time is compared with the voltage value measured last time and stored in the memory, and whether or not the potential difference ΔV between the voltage value measured this time and the voltage value measured last time exceeds a predetermined threshold A. Is determined (step S7).

  By the way, when the driver's hand approaches or comes into contact with a door handle (not shown), the amount of charge charged in the capacitors C1 and C2 decreases as described above. Therefore, the measured voltage value of the capacitor C1 or C2 is lower than the previously measured voltage value.

  In this case, the first controller 13 determines which of the voltage values of the lock-side capacitor C1 and the unlock-side capacitor C2 has decreased, and based on the result, the driver's intention, that is, unlocking (unlocking). It is determined whether the door in the state is going to be locked (locked) or, conversely, the door in the locked (locked) state is going to be unlocked (unlocked).

  Then, the present inventor can detect the drive electrode and the detection electrode by applying a pulse voltage to the drive electrode if the plate-like drive electrode and the detection electrode are arranged to face each other on the mounting surface of the circuit board in the proximity sensor. When the degree of decrease in the number of lines of electric force generated between the electrodes due to the proximity of the dielectric (reduction rate) differs between when the dielectric is hand and when it is water, and when the dielectric is human It was experimentally found that the degree of decrease in the number of lines of electric force was greater than when water was water. Therefore, the voltage induced in the detection electrode is lower when the dielectric is a human hand than when water is water.

  In addition, the field strength is proportional to (1 / distance), and even if the distance from the detection electrode is far away, the voltage does not drop abruptly. It was.

  Here, based on the experimental results shown in FIGS. 9 to 12, the above contents will be specifically described.

<Experimental conditions>
Place a 150 mm * 150 mm * 22 mm resin stand on a 410 mm * 300 mm GND plane (metal plate connected to GND), and place a flat electrode (electrode arrangement structure according to the conventional example) or opposite on the stand An electrode (an electrode arrangement structure according to this embodiment) was placed. The counter electrode is a metal plate of 25 mm * 2.5 mm * 0.3 mm facing each other at 10 mm intervals, and the plane electrode is a metal plate of 25 mm * 2.5 mm placed at a pitch of 1 mm. In this state, the voltage value between the case where one finger was placed at a position of 5.5 mm above the electrode and the case where 100 ml of water was placed was compared between the planar electrode and the counter electrode. The circuit constants are the same.

<Experimental result>
As shown in FIG. 9, the electrode voltage when one human finger is placed on the electrode at a position of 5.5 mm is 0.93 (V) in the case of the conventional electrode configuration, and the electrode of the present embodiment. In the case of the configuration, it was 0.83 (V). On the other hand, the electrode voltage when 100 ml of water is placed 5.5 mm above the electrode is 1.06 (V) in the case of the conventional electrode configuration, and 1.16 (V) in the case of the electrode configuration of the present embodiment. V).

  Further, as shown in FIGS. 9 to 10, the potential difference between the electrode voltage in a steady state and the electrode voltage when one human finger is placed at a position of 5.5 mm above the electrode is the same as that of the conventional electrode configuration. In this case, it was 0.26 (V), and in the case of the electrode configuration of this embodiment, it was 0.43 (V). On the other hand, the electrode voltage when 100 ml of water is placed at a position of 5.5 mm above the electrode is 0.13 (V) in the case of the conventional electrode configuration, and 0.10 (V) in the case of the electrode configuration of this embodiment. V). As can be seen from these, when one human finger is placed on the electrode at a position of 5.5 mm and when the electrode configuration is the present embodiment type, the voltage difference value with respect to the steady-state electrode voltage. Becomes larger. In addition, when 100 ml of water is placed at a position of 5.5 mm above the electrode, the voltage of the electrode with respect to the steady-state electrode voltage is the same regardless of whether it is the conventional electrode configuration or the electrode configuration of this embodiment type. There is no big difference in the difference value.

  Further, as shown in FIGS. 9 to 11, the rate of change of the electrode voltage when one human finger is placed on the electrode at a position of 5.5 mm with respect to the electrode voltage in the steady state is the same as that of the conventional electrode configuration. In this case, it was 21.80 (%), and in the case of the electrode configuration of this embodiment, it was 34.10 (%). On the other hand, the rate of change when 100 ml of water with respect to the steady-state electrode voltage is placed at a position of 5.5 mm above the electrode is 10.90 (%) in the case of the conventional electrode configuration, which is that of the electrode configuration of the present embodiment. In this case, it was 7.90 (%). As can be seen from these, when one human finger is placed on the electrode at a position of 5.5 mm and the electrode configuration is the present embodiment type, the change in the electrode voltage with respect to the steady-state electrode voltage. The rate is the largest. In addition, when 100 ml of water is placed at a position of 5.5 mm above the electrode, the voltage of the electrode with respect to the steady-state electrode voltage is the same regardless of whether it is the conventional electrode configuration or the electrode configuration of this embodiment type. There is no big difference in the rate of change.

  According to FIGS. 9 to 11, when one human finger is placed on the electrode at a position of 5.5 mm, and the electrode configuration is the present embodiment type, the voltage relative to the steady-state electrode voltage is shown. Since the rate of change is large, it can be said that the sensitivity is the best. In addition, when the electrode configuration is the present embodiment type, when one human finger is placed at a position of 5.5 mm above the electrode and when 100 ml of water is placed at a position of 5.5 mm above the electrode Is the largest voltage difference value. Therefore, when the electrode configuration is the present embodiment type, if an appropriate threshold is set, one person's finger is placed at a position of 5.5 mm above the electrode and 100 ml of water is above the electrode. It is inferred that it can be clearly distinguished from the case where it is placed at a position of 5 mm.

  FIG. 12 shows the result of a verification experiment for verifying the above reasoning. According to FIG. 12, when one human finger is placed at a position of 5.5 mm above the electrode and when 100 ml of water is placed at a position of 5.5 mm above the electrode, the detection results are as follows. Only when one electrode was placed at a position of 5.5 mm above the electrode, detection was possible in the electrode configuration of this embodiment. From this, it was proved that if an appropriate threshold value was set as inferred, it was possible to clearly discriminate between the case where one person's finger contacted and the case where 100 ml of water contacted.

  Therefore, in the present embodiment, the voltage values of the capacitors C1 and C2 measured when the driver's hand approaches or contacts the door handle (not shown) are measured when rain adheres to the door handle (not shown). The voltage is greatly lower than the voltages of the capacitors C1 and C2. For this reason, the threshold value A of the potential difference ΔV for determining whether the proximity sensor 1 is ON is larger than the potential difference when rain adheres to the door handle (not shown), and the driver's hand approaches or contacts the door handle (not shown). If it is determined that the proximity sensor 1 is turned on when the potential difference ΔV exceeds the threshold value A, the proximity sensor 1 is detected even if rain adheres to a door handle (not shown). The proximity sensor 1 is not turned on by erroneously detecting that the driver's hand has approached or contacted the door handle (not shown) without being turned ON.

  When the potential difference ΔV between the voltage value measured this time and the voltage value measured last time is compared with the predetermined threshold A (step S7), the charges charged in the capacitors C1 and C2 are second When the controller 18 reads the voltage value, it is discharged by the resistors R1 and R2 (steps S8 and S15).

  Then, as a result of the determination in step S7, when the potential difference ΔV between the voltage value measured this time and the voltage value measured last time exceeds a predetermined threshold A (step S7: Yes), the proximity sensor 1 It is determined that it has been turned on (step S9).

  When it is determined that the proximity sensor 1 is turned on in this way, the second controller 18 transmits a request signal from the antenna 7 to the electronic key 11 carried by the driver (step S10). The electronic key 11 that has received this request signal returns a code signal toward the antenna 7 (step S11).

  Then, the first controller 13 collates the code signal returned from the electronic key 11 with the code signal specific to the vehicle, and whether the code signal returned from the electronic key 11 matches the code signal specific to the vehicle. It is determined whether or not (step S12).

  As a result of this determination, if the code signal returned from the electronic key 11 matches the code signal unique to the vehicle (step S12: Yes), the actuator 12 is driven to lock or unlock the door. (Unlock) (step S13).

  Specifically, when the driver's hand approaches or contacts the surface side of a door handle (not shown), the voltage value of the lock-side capacitor C1 decreases. Therefore, the second controller 18 determines that the driver is trying to lock (lock) the door, and drives the actuator 12 to lock (lock) the door in the unlocked (unlocked) state.

  In addition, when the driver's hand is inserted inside the door handle, the voltage of the capacitor C2 on the unlock side decreases. Therefore, the second controller 18 determines that the driver is trying to unlock (unlock) the door, and drives the actuator 12 to unlock (unlock) the door in the locked (locked) state.

  As described above, when the actuator 12 is driven and the door is locked (locked) or unlocked (unlocked) (step S13), a series of processing ends. Thereafter, similar processing is repeated (step S14).

  By the way, as a result of the determination in step S7, when the potential difference ΔV of the voltage value between the capacitors C1 and C2 is equal to or less than the predetermined threshold A (ΔV ≦ A) (step S7: No), the proximity sensor 1 is in the OFF state. (Step S16).

  If the code signal returned from the electronic key 11 does not match the code signal specific to the vehicle as a result of the determination in step S12 (step S12: No), the process is terminated as it is.

  As described above, in the present embodiment, the proximity sensor 1 can clearly discriminate between the case where rain adheres to a door handle (not shown) and the case where the driver's hand approaches or contacts the door handle. Therefore, the attachment of rain to a door handle (not shown) is not erroneously detected as a driver's hand approaching or contacting the door handle. Therefore, the proximity sensor 1 can accurately detect only when the driver's hand approaches or contacts a door handle (not shown).

  That is, in the keyless entry device 10 including the proximity sensor 1, it is possible to prevent malfunction of locking or unlocking of the vehicle door due to erroneous detection of the proximity sensor 1 due to rain adhering to a door handle (not shown). Thereby, the effect that the locking or unlocking of the door unintended by the driver can be surely prevented is obtained.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIGS. Note that the configuration and processing of the keyless entry device are the same as those in the first embodiment, and thus detailed description thereof is omitted.

<Configuration of proximity sensor>
The configuration of the proximity sensor according to the present embodiment will be described with reference to FIGS.

  13 is a side view of the proximity sensor according to the present embodiment, FIG. 14 is a plan view of the proximity sensor, and FIG. 15 is a bottom view of the proximity sensor.

  As shown in FIGS. 13 and 14, the proximity sensor 1 according to the present embodiment is an elongated flat plate-like circuit board 2 and has one surface (hereinafter, “ A first drive electrode 3 and a first detection electrode (hereinafter referred to as “lock electrode”) 4 are vertically provided opposite to each other on the “surface”.

  Further, the surface of the long and narrow narrow portion 2B extending integrally from the wide portion 2A of the circuit board 2 (on the same plane as the surface on which the first drive electrode 3 and the first detection electrode are disposed). The second drive electrode 5 and the detection electrode (hereinafter referred to as “unlock electrode”) are longer than the first drive electrode 3 and the first detection electrode (lock electrode) 4 so as to sandwich the antenna 7. 6) are vertically arranged opposite to each other. The antenna is activated after the pulse voltage is applied to the second drive electrode 5 and the sensing operation is completed. Therefore, they do not operate simultaneously, and the electric field formed between the drive electrode and the detection electrode does not affect the antenna. However, since the metal electrode is close to the antenna, in practice, it is preferable to select a material that prevents magnetization as the electrode material.

  Further, a detection circuit 8 described later is printed on the circuit board 2.

  As shown in FIG. 4, the first drive electrode 3 and the first detection electrode (lock electrode) 4 are bent at both ends in the longitudinal direction of a long and narrow rectangular conductive metal plate such as a copper plate at right angles in opposite directions. The bent portion is soldered to the surface of the wide portion 2 </ b> A of the circuit board 2. As a result, the first drive electrode 3 and the first detection electrode (lock electrode) 4 are erected vertically opposite to the surface of the wide portion 2A of the circuit board 2 as described above.

  Similarly, the second drive electrode 5 and the second detection electrode (unlock electrode) 6 are also formed by bending the longitudinal ends of an elongated rectangular conductive metal plate such as a copper plate at right angles to each other in the opposite direction. The circuit board 2 is soldered on the same plane as the plane on which the first drive electrode 3 and the first detection electrode of the narrow portion 2B of the circuit board 2 are arranged. As a result, as described above, the first substrate 3 and the first detection electrode of the narrow portion 2B of the circuit board 2 are vertically provided opposite to each other on the same plane as the surface on which the first drive electrode 3 and the first detection electrode are disposed. ing. The first drive electrode 3 and the second drive electrode 5 are electrically connected to each other by pattern connection.

  The lock electrode (detection electrode), the drive electrode paired therewith, the unlock electrode (detection electrode), and the drive electrode paired therewith are erected on the same plane of the circuit board. It should be. It should be noted that, for example, an experiment was conducted so that the horizontal minimum distance between the opposing electrodes was ensured to be a predetermined distance or more without completely overlapping the opposing electrodes, and the area of the projected opposing portion was also a predetermined area or more. The angle may be given according to the conditions found in.

  Further, in the first embodiment, as described with reference to FIGS. 9 to 12, the present embodiment also has a case where one person's finger comes into contact with the electrode configuration as described above. The case where 100 ml of water comes into contact can be clearly distinguished.

  As described above, according to the present embodiment, a voltage value that is lower when the dielectric is a human hand than when it is water is output. Therefore, if this proximity sensor is built in the door handle, it is possible to recognize whether the dielectric that approaches or contacts the door handle is a human hand or water. Also, by disposing the antenna between the unlock electrode (detection electrode) and the drive electrode paired therewith, the unlock electrode (detection electrode) and the drive electrode and antenna paired therewith are the same. It can be arranged on a plane. Therefore, there is an effect that the thickness of the proximity sensor can be reduced. Furthermore, by disposing an antenna between the unlock electrode (detection electrode) and the drive electrode 5 that forms a pair with the unlock electrode, the output voltage value of the proximity sensor at normal times becomes high, so noise resistance is improved. This has the effect of improving the stability of the operation of the proximity sensor.

  In the above description, the proximity sensor is applied to the keyless entry device. However, the proximity sensor according to the present invention can be applied to any device other than the keyless entry device.

DESCRIPTION OF SYMBOLS 1 Proximity sensor 1A Electrode part of proximity sensor 2 Circuit board 2A Wide part of circuit board 2B Narrow part of circuit board 3 1st drive electrode 4 Lock electrode (1st detection electrode)
5 Second drive electrode 6 Unlock electrode (second detection electrode)
7 Antenna 8 Detection Circuit 9 Case 10 Keyless Entry Device 11 Electronic Key (Portable Transmitter)
12 Actuator 13 1st controller (Keyless ECU)
14 operational amplifier 15 diode 16 operational amplifier 17 diode 18 2nd controller (microcomputer)
A Threshold of potential difference C1, C2 Capacitor R1, R2 Resistance Vcc DC power supply ΔV Potential difference

Claims (7)

A circuit board on which a detection circuit is printed;
In a proximity sensor comprising one drive electrode mounted on one surface of the circuit board and electrically connected to the detection circuit, and one detection electrode,
A proximity sensor characterized in that the flat drive electrode (1) and the detection electrode (1) are erected so as to face each other on one surface of the circuit board.   2. The proximity sensor according to claim 1, wherein the other driving electrode and the other detection electrode having a flat plate shape are erected opposite to the other surface of the circuit board. A circuit board on which a detection circuit is printed;
In a proximity sensor comprising one drive electrode mounted on one surface of the circuit board and electrically connected to the detection circuit, and one detection electrode,
The flat plate-like one drive electrode and the one detection electrode are erected so as to face each other of the circuit board, and the one drive electrode and the one detection electrode are arranged between the one drive electrode and the one detection electrode. A proximity sensor comprising an antenna that transmits and receives signals to and from a portable transmitter when proximity or contact with a detection electrode is detected.   A flat plate-like other drive electrode and another detection electrode are erected on the same plane on which the antenna of the circuit board is disposed, facing each other at a position separated from the other drive electrode and the other detection electrode. The proximity sensor according to claim 3. A proximity sensor built into the door handle of the vehicle;
An antenna that transmits and receives signals to and from a portable transmitter when the proximity sensor detects proximity or contact of the person to the door handle;
An actuator for locking or unlocking a vehicle door;
When the proximity sensor is turned ON / OFF by the output of the proximity sensor, the proximity sensor is turned ON, and the code signal received by the antenna from the portable transmitter matches the code signal unique to the vehicle. A controller for driving or locking the door by driving an actuator;
In a keyless entry device comprising:
The proximity sensor is configured by the proximity sensor according to any one of claims 1 to 4, and the controller is configured so that the proximity sensor is turned on when an output decrease of the proximity sensor exceeds a predetermined threshold. A keyless entry device characterized in that a determination is made. The controller is
Capacitor charging with a voltage output from the proximity sensor by supplying a driving voltage to the driving electrode, measurement of a charging voltage value, and discharging of the charging voltage are repeatedly controlled every predetermined time,
The charge voltage value measured this time is compared with the charge voltage value measured last time, and when the difference between the two exceeds a predetermined threshold value, it is determined that the proximity sensor is turned on. 5. A keyless entry device according to 5.   One of the one detection electrode or the other detection electrode constitutes a lock electrode that detects a human action when the door is locked, and the other constitutes an unlock electrode that detects a human action when the door is unlocked. The keyless entry device according to claim 5 or 6.