JP5183078B2 - Human body approach detection device - Google Patents

Description

  The present invention relates to a human body approach detection device that is used in a system for controlling locking and unlocking of a vehicle door of a vehicle such as an automobile and detects the approach of the human body to a vehicle door handle.

  As a system for controlling the operation of locking and unlocking a vehicle door of a vehicle such as an automobile, a sensor electrode 31 is provided in the housing 30 of the vehicle door handle in the vicinity of the inside of the wall on the door side as shown in FIG. There is one that locks and unlocks the door when it comes into contact with the wall surface on the door side of the vehicle door handle (Patent Document 1).

  In the conventional system of this type, the body of the vehicle body is normally electrically grounded, and the human body is based on the capacitance formed by the sensor electrode 31 in the door 32 of the vehicle body and the housing 30 of the handle. An approach to the door handle is determined. That is, the capacitance detected by the sensor electrode 31 changes 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. A person's approach to the vehicle door handle is detected by a change in electric capacity.

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

  However, the conventional system for controlling the operation of locking and unlocking the vehicle door of the vehicle is based on the capacitance formed by the sensor electrode 31 in the vehicle door 32 and the housing 30 of the door handle. When the shape of the door 32 changes, the initial capacitance when the human body is not approaching and the sensitivity when the human body approaches are greatly changed, the sensor is not stable, and a malfunction occurs. There is.

  Also, when water droplets such as raindrops adhere to the vicinity of the door handle, the capacitance of the vehicle door 32 and the sensor electrode 31 changes via the adhered water droplets, and it is erroneously detected that the human body is approaching. There is a problem of end up.

  Further, when there is a transmitting antenna used in the keyless entry system of the automobile near the sensor electrode 31, there is capacitive coupling between the transmitting antenna and the sensor electrode 31, and radio waves are transmitted from the transmitting antenna. When this occurs, there is a problem that the electrostatic capacity between the transmitting antenna and the sensor electrode 31 is changed due to the influence, and the human body is erroneously detected as approaching. In addition, when a transmitting antenna of another automobile approaches, a malfunction may occur similarly.

  These problems are determined by storing various changes in capacitance as signal patterns, such as when a human body approaches or when water adheres, and comparing them with the actually generated capacitance signal pattern. However, there is a problem that a large amount of data processing and a storage device are required, which is expensive and complicated.

  Therefore, the present invention can prevent malfunctions even when the shape of the door is changed, when water droplets are attached, or when radio waves are transmitted from the transmitting antenna, and an inexpensive and complicated pretreatment is performed. An object of the present invention is to provide an unnecessary human body approach detection device.

  In order to achieve the above object, the present invention provides a sensor electrode that is provided in the vicinity of a door side wall inside a housing of a vehicle door handle, the capacitance of which changes as a human body approaches, and the interior of the housing. An auxiliary electrode that suppresses a change in capacitance due to a change in the external environment of the sensor electrode, and the auxiliary electrode is supplied with a ground potential or a potential equivalent to the sensor electrode. It is a detection device.

  The human body approach detection device according to the present invention is configured as described above, so that the capacitance change of the sensor electrode is suppressed by the auxiliary electrode even when the shape of the door changes or when water drops adhere. Therefore, it is possible to prevent a malfunction from occurring. In addition, 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 potential equivalent to the sensor electrode means a potential that is the same as or close to that of the sensor electrode and has very small capacitive coupling with the sensor electrode.

  In the human body approach detection device according to the present invention, it is preferable that the auxiliary electrode includes a ground electrode provided between the sensor electrode and a wall surface opposite to the door inside the housing. Since the capacitance between the door and the sensor electrode decreases, even if the shape of the door changes, the characteristics of the human body approaching detection device according to the present invention hardly change accordingly, and the sensor It is possible to prevent erroneous detection of electrodes.

  In the human body approach detection device according to the present invention, it is preferable that the auxiliary electrode includes a first shield electrode that applies a potential equal to the sensor electrode between at least the sensor electrode via the vehicle door handle and the door. The first shield electrode is preferably provided in the vicinity of the side wall of the door inside the housing, surrounds the sensor electrode, and is given a potential equal to that of the sensor electrode. By providing the first shield electrode in this way, even if the space between the vehicle door handle and the door is immersed in water droplets, the first shield electrode is interposed between the door and the sensor electrode, and the door and the first shield electrode Therefore, the capacitive coupling between the door and the sensor electrode is reduced as compared with the case where the first shield electrode is not provided. Further, since the first shield electrode is set to the same potential as the sensor electrode, the capacitive coupling between the first shield electrode and the sensor electrode hardly occurs. For this reason, when the space between the vehicle door handle and the door is immersed in water droplets, it is possible to prevent the human body from being recognized as approaching.

  Furthermore, in the human body approach detection device according to the present invention, the auxiliary electrode is provided between a wall surface on the opposite side of the door inside the housing and the ground electrode, and is provided with a potential equal to that of the sensor electrode. It is preferable to include two shield electrodes, and even if the second shield electrode is provided in this way, even if the wall surface of the housing provided with the sensor electrode and the opposite wall surface are immersed in water droplets via the upper surface The second shield electrode is interposed between the sensor electrode via the water droplet and the ground electrode. Further, since the sensor electrode and the second shield electrode are at the same potential, Capacitive coupling does not occur between the ground electrodes.

  In the human body approach detection device according to the present invention, the auxiliary electrode is provided between the sensor electrode and a wall surface on the opposite side of the door inside the housing, and a second shield to which a potential equivalent to the sensor electrode is applied. Preferably, the electrode further includes an electrode, and the auxiliary electrode further includes a third shield electrode that surrounds the ground electrode and is provided with a potential equal to that of the sensor electrode. The third shield electrode can function in the same manner as the second shield electrode without providing the second shield electrode.

  The sensor electrode and the auxiliary electrode are preferably formed by the same flexible printed circuit. In this case, an electrostatic capacitance for detecting a change in capacitance of the sensor electrode is formed on the flexible printed circuit. It is preferable that a capacitance detection circuit is mounted.

  The human body approach detection device according to the present invention preferably further includes a transmission antenna used in a keyless entry system between the auxiliary electrode and the wall surface on the opposite side of the door inside the housing, In this case, the auxiliary electrode is provided between the sensor electrode and the wall surface opposite to the door inside the housing, and includes a second shield electrode to which a potential equivalent to the sensor electrode is applied, The capacitance between the sensor electrode and the transmission antenna is reduced, and the variation in capacitance due to the output of radio waves from the transmission antenna can be reduced. Furthermore, in this case, the auxiliary electrode is provided between the sensor electrode and the ground electrode provided between the wall surface opposite to the door inside the housing and the sensor electrode, It is preferable to include a second shield electrode to which an electric potential equivalent to that of the sensor electrode is applied. Thus, by providing a ground electrode between the transmitting antenna and the sensor electrode, the second shield electrode is provided. In addition, by reducing the electrostatic capacitance between the transmitting antenna and the sensor electrode, and further providing a second shield electrode between the ground electrode and the sensor electrode, the capacitive coupling between the sensor electrode and the ground electrode is dominant. Can be prevented, and a decrease in sensitivity to the approach of the human body can be prevented. In addition, it is preferable that the oscillation circuit used for the sensor electrode, the auxiliary electrode, and the keyless entry system is formed by the same flexible printed circuit.

  Furthermore, in the human body approach detection device according to the present invention, it is preferable that a groove is formed in at least one of the sensor electrode and the auxiliary electrode. In this case, the width of the groove is shredded by the groove. It is preferable that the width is the same as or shorter than the width of the electrode.

  Furthermore, the human body approach detection device according to the present invention further includes a light emitter that is provided in the housing and emits a detection state by the sensor electrode, and at least a part of the housing is formed of a translucent material. In this case, at least the sensor electrode and the auxiliary electrode are formed on a flexible printed circuit, and at least the vicinity of the light emitter of the flexible printed circuit is formed of a translucent material. It is preferable that at least the vicinity of the light emitter of the sensor electrode and the auxiliary electrode is formed of a translucent conductive material.

  As described above, according to the present invention, it is possible to prevent malfunction even when the shape of the door changes or when water droplets adhere to it, and a human body approach detection device that is inexpensive and does not require complicated preprocessing. Can be provided.

  Next, a first embodiment of a human body approach detection device according to the present invention will be described based on the drawings. FIG. 1 is a plan view of a vehicle door handle 4 of an automobile on which the human body approach detection device according to the first embodiment is mounted, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a circuit diagram illustrating a schematic configuration of the human body approaching detection apparatus according to the first embodiment. The human body approach detection sensor according to the first embodiment is used in 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. The human body approaching detection apparatus according to the first embodiment includes a sensor unit 10 and a main circuit unit 20.

  The sensor unit 10 is provided inside the wall surface 6a on the door 2 side in the housing 6 that constitutes the vehicle door handle 4, and extends in the longitudinal direction along the wall surface 6a (a direction perpendicular to the paper surface of FIG. 2). The first shield electrode 12 provided inside the wall surface 6a and surrounding the sensor electrode 11 and the sensor electrode 11 in the housing 6 that is farther from the door 2 than the sensor electrode 11 in the housing 6 A ground electrode 13 provided at a position closer to the sensor electrode 11 than a distance between the electrode 11 and the door 2, and a second shield electrode 14 provided at a position farther from the door 2 than the ground electrode 13 in the housing 6. And. The first shield electrode 12, the ground electrode 13, and the second shield electrode 14 constitute an auxiliary electrode for the sensor electrode 11.

  As shown in FIG. 3, the sensor unit 10 is composed of a single flexible printed circuit (FPC). The sensor electrode 11, the first shield electrode 12, the ground electrode 13, and the second shield electrode 13 are made of polyethylene terephthalate. (PET), polyethylene naphthalate (PEN), or copper, copper alloy or aluminum patterned on an insulating plate 15 made of an insulator such as an epoxy resin. The sensor electrode 11 is formed in a rectangular shape, and the first shield electrode 12 is formed in a square shape surrounding the sensor electrode 11. The ground electrode 13 is formed in a rectangular shape, and is grounded via a vehicle body. The second shield electrode 14 is formed in a rectangular shape. The human body proximity sensor is housed in the housing 6 of the vehicle door handle 4 in a state in which such an FPC is bent as shown in FIG. 2 along the dotted line shown in FIG. In addition, although the sensor part 10 was comprised by FPC, you may comprise using a metal or a rigid printed circuit board, an electric wire, or a membrane.

  The main circuit unit 20 is configured as follows. The sensor electrode 11 is connected to the input end of the detection circuit 23. The sensor electrode 11 is also connected to one input terminal of buffers 21 and 22 comprising operational amplifiers. The other input ends of the buffers 21 and 22 are connected to the first and second shield electrodes 12 and 14, respectively, and to the respective output ends. The buffer 21 keeps the sensor electrode 11, the first shield electrode 12, and the second shield electrode 14 in a high impedance state, and prevents charging and discharging between them at the same potential. A 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 capacitance between the sensor electrode 11 and the ground electrode 13, the door 2, and the human body that is 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 a detection signal from the LPF 24 and outputs a switch to an external electric circuit according to the signal level.

  FIG. 4 is a circuit diagram showing an example of the detection circuit 23 in which the duty ratio changes according to the capacitance C. The detection circuit 23 includes a trigger signal generation circuit 231 that outputs a trigger signal TG having a constant period, and a timer circuit 232 that outputs a pulse signal Po whose duty ratio changes depending on the capacitance connected to the input end. It is prepared for.

  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 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 output from the trigger signal generation circuit 231 as shown in FIG. 5 with a predetermined threshold value Vth2 divided by the resistors R1, R2, and R3, and generates a trigger signal TG. Output synchronized set pulse. This set pulse sets the Q output of RS-FF 2323. This 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. Thereby, as shown in FIG. 5, 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. Accordingly, 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 ground electrode 13, as shown in FIG. The LPF 24 smoothes the output to output a DC detection signal Vout as shown in FIG.

  In FIG. 5, 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 first embodiment, when a hand approaches the sensor region of the sensor electrode 11 of the wall 6a on the door side of the housing 6 of the vehicle door handle 4, the sensor electrode 11, the ground electrode 13, and the door 2 In addition to the capacitance between the sensor electrode 11 and the sensor body 11, capacitive coupling with the human body as the ground 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. 5 indicates the human body proximity state. Then, when the entire sensor region of the sensor electrode 11 of the door-side wall surface 6a of the housing 6 of the vehicle door handle 4 is touched and completely covered, the capacitance between the detected sensor electrode 11 and the ground is detected. Reaches the maximum value. The human body approach detection device according to the first embodiment uses the trigger when the electrostatic capacity reaches an arbitrary threshold value between the electrostatic capacity when the hand is not present and the maximum value as a trigger. It is configured to perform unlocking. For this threshold value, an appropriate value may be determined from the amount of increase in electrostatic capacitance caused by how the hand is applied to the door handle 4.

  Since the sensor unit 10 of the human body approaching detection apparatus according to the first embodiment is provided with the ground electrode 13 at a position closer to the door 2 than the sensor electrode 11 in the housing 6, the capacitance between the sensor electrode 11 and the ground. Since the capacitive coupling between the sensor electrode 11 and the ground electrode 13 becomes more dominant than between the sensor electrode 11 and the door 2, even if the shape of the door changes compared to the case without the ground electrode 13, Accordingly, the characteristics of the human body proximity sensor 10 rarely change, and erroneous detection of the sensor electrode 11 can be prevented. The sensitivity of the sensor electrode 11 can be adjusted by changing the area, position, or shape of the ground electrode 13 with respect to the sensor electrode 11. Even if the ground electrode 13 is not provided, the ground electrode 13 is not provided when the first shield electrode 12 and / or the second shield electrode 14 perform the same function as the ground electrode 13. Also good. For example, when the potential applied to the shield electrode 12 or 14 is not completely the same as the sensor electrode 11, capacitive coupling occurs between the sensor electrode 11 and the first shield electrode 12 or the second shield electrode 14, and the sensor electrode Since the distance from the first shield electrode 12 or the second shield electrode 14 is closer than the distance from the door 11 to the door 2, the capacitive coupling between the sensor electrode 11 and the first shield electrode 12 or the second shield electrode 14 is dominant. Therefore, even if the shape of the door changes compared with the case where the first shield electrode 12 or the second shield electrode 14 is not provided, the characteristics of the human body proximity sensor 10 are less likely to change accordingly, and the sensor electrode 11 False detection can be prevented.

  Moreover, the effect | action of the 1st shield electrode 12 in the human body approach detection apparatus which concerns on 1st Embodiment is demonstrated based on the schematic diagram shown in FIG. In the first embodiment, since the sensor unit 10 is provided with the first shield electrode 12 so as to surround the sensor electrode 11, a water droplet A is formed between the vehicle door handle 4 and the door 2 as shown in FIG. 6. 1, the first shield electrode 12 is interposed between the door 2 and the sensor electrode 11, and capacitive coupling between the door 2 and the first shield electrode 12 occurs. Is less than that in the case where the first shield electrode 12 is not provided. Further, since the first shield electrode 12 is set to the same potential as the sensor electrode 11 by the buffer 21, the capacitive coupling between the first shield electrode 12 and the sensor electrode 11 hardly occurs. For this reason, when the space | interval between the vehicle door handle 4 and the door 2 is immersed with a water droplet, it can prevent being recognized as a human body approaching.

  Furthermore, the effect | action of the 2nd shield electrode 14 in the human body approach detection apparatus which concerns on 1st Embodiment is demonstrated based on the schematic diagram shown in FIG. In the first embodiment, the sensor unit 10 is provided with the second shield electrode 14 between the wall surface 6b on the side opposite to the door 2 and the ground electrode 13, so that as shown in FIG. Even if the surface 6a of the provided housing 6 and the surface 6b opposite to the surface 6b are immersed in the water droplet B through the upper surface, the second shield is provided between the sensor electrode 11 and the ground electrode 13 through the water droplet B. Since the electrode 14 is interposed, and the sensor electrode 11 and the second shield electrode 14 are at the same potential, capacitive coupling is generated between the sensor electrode 11 and the ground electrode 13 via the water droplet B. Absent.

  Further, the first shield electrode 12 and the second shield electrode 14 have a function of limiting the sensor range of the sensor electrode 11. That is, for example, even when the human body comes into contact with the portion of the surface 6a of the housing 6 where the first shield electrode 12 is provided, the capacitance with the human body as the ground is generated between the first shield electrode 12 and the ground. Therefore, it does not occur between the sensor electrode 11 and misrecognition can be prevented. Similarly, even if the human body contacts the surface 6 b of the housing 6, the electrostatic capacitance with the human body as the ground is generated only between the second shield electrode 14 and the sensor electrode 11. Absent.

  In the human body approach detection device according to the first embodiment described above, the first shield electrode 12 is not necessarily provided on the same surface as the sensor electrode 11, and the sensor electrode on the wall surface 6 a on the door 2 side of the housing 6. 11 may be provided on different planes as long as the potential equivalent to that of the sensor electrode 11 is generated around the corresponding position of the sensor 11. The periphery of the position corresponding to the sensor electrode 11 is only in the vicinity of the sensor electrode 11. In addition, a connection portion between the door handle 4 and the door 2 is also included. If the second shield electrode 14 performs the same function as described above without the ground electrode 13, the ground electrode 13 may not be provided. In this case, the second shield electrode 14 is not connected to the housing 6. The sensor electrode 11 may be adjusted by changing the shape, size, and position of the second shield electrode 14 at a position away from the wall 6b on the side opposite to the door 2 inward. . Furthermore, the ground electrode 13 and the second shield electrode 14 are provided not only in the vicinity of the wall surface 6b on the side opposite to the door 2 of the housing 6, but also in the vicinity of other wall surfaces other than the wall surface 6a on the door 2 side, It is possible to prevent erroneous detection of the sensor electrode 11 when a human body touches those wall surfaces.

  Next, a second embodiment of the human body approach detection device according to the present invention will be described based on the drawings. FIG. 8 is a diagram corresponding to FIG. 2 of the first embodiment of the human body approaching detection apparatus according to the second embodiment. The human body approach detection device according to the second embodiment is a keyless entry system, that is, when a user carries a remote control and approaches or separates from a vehicle door, the vehicle door is locked and unlocked using the vehicle key. Used for things that are not used. For this reason, unlike the first embodiment, the sensor unit 10 of the human body approaching detection apparatus according to the first embodiment is provided with a transmission antenna 16 used in the keyless entry system. The transmitting antenna 16 is provided at a position farther from the door 2 than the second shield electrode 14. By arranging the sensor electrode 11 or the ground electrode 13 between the sensor electrode 11 or the ground electrode 13 and the transmission antenna 16 in this manner on the second shield electrode 14, the sensor electrode 11 or the ground electrode 13 is affected by the electromagnetic wave generated from the transmission antenna 16. You can prevent it. The basic structure of the keyless entry system is described in Patent Document 1.

  Next, a third embodiment of the human body approaching detection apparatus according to the present invention will be described based on the drawings. FIG. 9 is a diagram corresponding to FIG. 2 of the first embodiment of the human body approaching detection apparatus according to the third embodiment. The human body approach detection device according to the third embodiment is used in a keyless entry system as in the second embodiment, but the position of the transmitting antenna 16 is different from that in the second embodiment. That is, in the human body approach detection device according to the third embodiment, the transmission antenna 16 is provided between the ground electrode 13 and the second shield electrode 14 as shown in FIG. A third shield electrode 17 is provided on the same plane as the ground electrode 13 so as to surround the periphery of the ground electrode 13. As described above, by providing the third shield electrode 17 around the ground electrode 13, the influence of the electromagnetic wave generated from the transmitting antenna 16 is absorbed by the third shield electrode 17 and hardly given to the ground electrode 13. Therefore, sufficient sensitivity of the sensor electrode 11 can be maintained.

  Next, a fourth embodiment of the human body approach detection device according to the present invention will be described with reference to the drawings. FIG. 10 is a diagram corresponding to FIG. 2 of the first embodiment of the human body approaching detection apparatus according to the fourth embodiment. The human body approach detection device according to the fourth embodiment is used for a keyless entry system as in the second embodiment, but differs from the second embodiment in that the ground electrode 13 is not provided. That is, in the human body approaching detection apparatus according to the fourth embodiment, only the second shield electrode 14 is provided between the sensor electrode 11 and the transmitting antenna 16, and the ground electrode 13 is not provided. . As described above, by providing the second shield electrode 14 between the sensor electrode 11 and the transmission antenna 16, the capacitance between the sensor electrode 11 and the transmission antenna 16 is reduced. The variation in capacitance due to the output of radio waves can be reduced.

  Next, a fifth embodiment of the human body approach detection device according to the present invention will be described with reference to the drawings. FIG. 11 is a diagram corresponding to FIG. 2 of the first embodiment of the human body approaching detection apparatus according to the fifth embodiment. The human body approach detection device according to the fifth embodiment is used for a keyless entry system as in the second embodiment, but the second embodiment is different in that the positions of the ground electrode 13 and the second shield electrode 14 are different. It differs in that it is the opposite. That is, in the human body approaching detection apparatus according to the fourth embodiment, the second shield electrode 14 is provided on the sensor electrode 11 side, and the ground electrode 13 is provided on the transmitting antenna 16 side. By providing the ground electrode 13 between the transmitting antenna 16 and the sensor electrode 11 in this manner, the transmitting antenna 16 and the sensor electrode 11 can be compared with the case where only the second shield electrode 14 is provided as in the fourth embodiment. The electrostatic capacity can be reduced. On the other hand, when the ground electrode 13 is provided in the vicinity of the sensor electrode 11, the capacitive coupling between the sensor electrode 11 and the ground electrode 13 becomes dominant, and the sensitivity to the approach of the human body is lowered. In the embodiment, since the second shield electrode 14 is provided between the ground electrode 13 and the sensor electrode 11, the capacitive coupling between the sensor electrode 11 and the ground electrode 13 can be prevented from being dominant, and the human body It is possible to prevent a decrease in sensitivity to the approach of.

  Next, a sixth embodiment of the human body approach detection device according to the present invention will be described with reference to the drawings. FIG. 12 is a diagram corresponding to FIG. 2 of the first embodiment of the human body proximity sensor according to the sixth embodiment. In the human body proximity sensor according to the sixth embodiment, the third shield electrode 17 is provided on the same plane as the ground electrode 13 so as to surround the ground electrode 13 as shown in FIG. The 2nd shield electrode 14 is not provided like the form. In the human body proximity sensor according to the third embodiment, the third shield electrode functions in the same manner as the second shield electrode 14 of the first embodiment.

  Next, a seventh embodiment of the human body approach detection device according to the present invention will be described with reference to the drawings. FIG. 13 is a plan view of a flexible printed circuit used in the human body approach detection device according to the seventh embodiment, and FIG. 14 corresponds to FIG. 2 of the first embodiment of the human body approach detection device according to the seventh embodiment. It is a figure to do. The human body approach detection device according to the seventh embodiment includes grooves 26, 27 extending in the longitudinal direction in the sensor electrode 11, the first shield electrode 12, the ground electrode 13, and the second seal electrode 14, respectively, as shown in FIGS. 28 and 29 are formed. The grooves 26, 27, 28, and 29 are formed by folding back patterns extending in the longitudinal direction of the electrodes 11, 12, 13, and 14 in the longitudinal direction. The widths of the grooves 26, 27, 28, and 29 are The width of the pattern extending in the longitudinal direction of each electrode is the same as or shorter than that of the pattern.

  The transmission antenna 16 has a structure in which a winding generally wound around a ferrite called a bar antenna is wound and is driven by forming a series resonance circuit with a capacitor. Therefore, each electrode 11, 12 is output by the output of the transmission antenna 16. , 13, and 14 generate eddy currents, which lowers the output of the transmitting antenna 16 or changes the resonance frequency of the circuit due to its impedance, which degrades the characteristics. The human body approach detection device according to the embodiment reduces eddy currents generated from the electrodes 11, 12, 13, and 14 by forming grooves 26, 27, 28, and 29 in the electrodes 11, 12, 13, and 14, respectively. be able to. In the human body approach detection device according to the seventh embodiment, the widths of the grooves 26, 27, 28, and 29 of the electrodes 11, 12, 13, and 14 are the same as or more than the width of the pattern extending in the longitudinal direction of the electrodes. Therefore, the potentials of the grooves 26, 27, 28, and 29 are the same as the surroundings, and the effects of the electrodes 11, 12, 13, and 14 are not reduced.

  In the human body approach detection device according to the seventh embodiment, the grooves 26, 27, 28, and 29 are formed in each of the electrodes 11, 12, 13, and 14, but are formed in all the electrodes 11, 12, 13, and 14. You don't have to. Each groove 26, 27, 28, 29 is formed by turning back a pattern extending in the longitudinal direction of each electrode 11, 12, 13, 14; however, as shown in FIG. You may form in a comb-tooth shape.

  In the human body approach detection device according to the first to fourth embodiments described above, only the sensor unit 10 is configured by FPC, but the main circuit unit 20 is also formed on the same insulating plate as the sensor unit 10 and is used as FPC. It may be configured. Furthermore, in the human body approaching detection apparatus according to the second and third embodiments, an oscillation circuit used for the keyless entry system may be formed on the insulating plate 15 of the FPC.

  In the housing 6 of the vehicle door handle 4 of the human body approach detection device according to the first to fourth embodiments, a light emitter such as LED or EL is provided to lock and unlock the vehicle door of the automobile. You may comprise so that light-emitting bodies, such as LED and EL, may be light-emitted in the case of the detection used as a trigger. At this time, at least a part of the housing 6, that is, a part where light is to be emitted needs to be configured to be translucent, and when a sensor electrode or the like is disposed in the part, a translucent one is used as an insulating plate. Then, a pattern is formed by applying a translucent conductive material on the insulating plate. Examples of the light-transmitting conductive material include ITO (tin-doped indium oxide), ZnO (zinc oxide), and a conductive polymer (PEDOT / PSS).

  In the human body approach detection device according to the first embodiment, the capacitance detection circuit using the known timer IC in which the duty ratio of the output pulse changes according to the time constant of the resistor and the capacitor has been described. However, the present invention is not limited to this. A method of directly measuring impedance, a method of measuring an oscillation frequency by configuring an oscillation circuit, a method of measuring a charge / discharge time by configuring an RC charge / discharge circuit, a charge charged with a known voltage and a known capacity To measure the voltage, or the method of measuring the number of times until the predetermined voltage is charged to the known capacity by moving the charge multiple times, setting a threshold value for the detected capacitance value, Alternatively, processing such as a trigger may be performed when the signal waveform of the capacitance is analyzed and the corresponding capacitance waveform is obtained.

  In the human body approach detection device according to the first embodiment, buffers 21 and 22 having higher input impedance and lower output impedance than the voltage follower of the operational amplifier are configured, and the sensor electrode 11, the first shield electrode 12, the second shield electrode 14, Are connected via the buffers 21 and 22, but it is sufficient that the input amplifier has a high input impedance and a low output impedance even if it is not a voltage follower. The operational amplifier used at this time is a high speed (low delay) Time) and preferably have a high slew rate characteristic. Alternatively, the voltage applied to the sensor electrode may be captured by an AD converter, the same voltage may be output by a DA converter, and connected to the first shield electrode or the second shield electrode. Further, the applied voltage of the sensor electrode from the detection circuit is connected to the non-inverting input of the operational amplifier, the inverting input is connected to the sensor electrode, and the non-inverting input is directly connected to the first shield electrode or the second shield electrode. You can drive. Furthermore, even when a rectangular wave (digital signal) having the same cycle as the signal applied to the sensor electrode is applied to the shield electrode, an effect close to the same potential can be obtained.

1 is a plan view of a vehicle door handle of an automobile on which a first embodiment of a human body approach detection device according to the present invention is mounted. It is sectional drawing along the II-II line of FIG. It is a circuit diagram which shows schematic structure of the human body approach detection apparatus which concerns on 1st Embodiment. It is a circuit diagram which shows an example of the detection circuit of the human body approach detection apparatus which concerns on 1st Embodiment. It is an operation | movement waveform diagram of the human body approach detection apparatus which concerns on 1st Embodiment. It is the schematic which shows the state where the space between the vehicle door and the vehicle door handle was immersed in water droplets. It is the schematic which shows the state in which the housing of the vehicle door handle was immersed in the water droplet. It is a figure corresponding to FIG. 2 of 2nd Embodiment of the human body approach detection apparatus which concerns on this invention. It is a figure corresponding to FIG. 2 of 3rd Embodiment of the human body approach detection apparatus which concerns on this invention. It is a figure corresponding to FIG. 2 of 4th Embodiment of the human body approach detection apparatus which concerns on this invention. It is a figure corresponding to FIG. 2 of 5th Embodiment of the human body approach detection apparatus which concerns on this invention. It is a figure corresponding to FIG. 2 of 6th Embodiment of the human body approach detection apparatus which concerns on this invention. It is a top view of the flexible printed circuit used for 7th Embodiment of the human body approach detection apparatus based on this invention. It is a figure corresponding to FIG. 2 of 1st Embodiment of the human body approach detection apparatus which concerns on 7th Embodiment. It is a top view of the flexible printed circuit of the other aspect of the electrode used for 7th Embodiment of the human body approaching detection apparatus which concerns on this invention. It is a top view of the door handle for vehicles of the car by which the conventional human body approach detection device is carried.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Door, 4 ... Door handle for vehicles, 6 ... Housing, 6a ... Door side wall surface, 11 ... Sensor electrode, 12 ... 1st shield electrode, 13 ... Ground Electrode, 14 ... second shield electrode

Claims (16)

A sensor electrode that is provided in the vicinity of the side wall of the door inside the housing of the vehicle door handle, and whose capacitance changes as a human body approaches;
An auxiliary electrode provided inside the housing to suppress a change in capacitance due to a change in the external environment of the sensor electrode,
The auxiliary electrode includes a first shield electrode that applies a potential equal to the sensor electrode between the sensor electrode via the vehicle door handle and the door.   The human body approach detection device according to claim 1, wherein the auxiliary electrode further includes a ground electrode provided between a wall surface on the opposite side of the door inside the housing and the sensor electrode.   The said 1st shield electrode is provided in the said door side wall surface inside the said housing, surrounds the circumference | surroundings of the said sensor electrode, and the electric potential equivalent to the said sensor electrode is given. 2. The human body approach detection device according to 2.   The auxiliary electrode further includes a second shield electrode provided between the sensor electrode and a wall surface on the opposite side of the door inside the housing, to which a potential equal to the sensor electrode is applied. Item 4. The human body approach detection device according to any one of Items 1 to 3. A sensor electrode that is provided in the vicinity of the side wall of the door inside the housing of the vehicle door handle, and whose capacitance changes as a human body approaches;
An auxiliary electrode provided inside the housing to suppress a change in capacitance due to a change in the external environment of the sensor electrode,
The auxiliary electrode includes a ground electrode provided between a wall surface opposite to the door inside the housing and the sensor electrode, and a wall surface opposite to the door inside the housing and the ground electrode. And a second shield electrode provided with a potential equal to that of the sensor electrode. A sensor electrode that is provided in the vicinity of the side wall of the door inside the housing of the vehicle door handle, and whose capacitance changes as a human body approaches;
An auxiliary electrode provided inside the housing to suppress a change in capacitance due to a change in the external environment of the sensor electrode,
The auxiliary electrode is provided between the sensor electrode and a ground electrode provided between a wall surface opposite to the door inside the housing and the sensor electrode, and is equivalent to the sensor electrode. And a second shield electrode to which the electric potential is applied.   The human body approach according to claim 5, wherein the auxiliary electrode further includes a first shield electrode that applies a potential equal to the sensor electrode between at least the sensor electrode via the vehicle door handle and the door. Detection device.   8. The human body approach detection device according to claim 5, wherein the auxiliary electrode further includes a third shield electrode that surrounds the ground electrode and is provided with a potential equal to that of the sensor electrode. 9. The human body approach detection device according to claim 1, wherein the sensor electrode and the auxiliary electrode are formed on the same flexible insulating plate . The human body approach detection device according to claim 9, wherein a capacitance detection circuit that detects a change in capacitance of the sensor electrode is mounted on the flexible insulating plate .   The human body approach detection according to any one of claims 1 to 10, further comprising a transmitting antenna used in a keyless entry system between the auxiliary electrode and a wall surface on the opposite side of the door inside the housing. apparatus. 12. The human body approach detection device according to claim 11, wherein the sensor electrode, the auxiliary electrode, and the oscillation circuit used in the keyless entry system are formed on the same flexible insulating plate .   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.   14. The human body approach detection device according to claim 13, wherein the width of the groove is the same as or shorter than the width of the electrode shredded by the groove. A light emitter that is provided in the housing and emits light detected by the sensor electrode;
The human body approach detection device according to claim 1, wherein at least a part of the housing is formed of a translucent material. At least the sensor electrode and the auxiliary electrode are formed on a flexible insulating plate ,
At least the light emitter in the vicinity of the flexible insulating plate is formed of a translucent material,
The human body approach detection device according to claim 15, wherein at least the light emitter in the vicinity of the sensor electrode and the auxiliary electrode is formed of a translucent conductive material.

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