JP4056660B2 - Capacitance sensor device and safety device for electric power window device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionCapacitance sensor device andThe present invention relates to a safety device for an electric power window device (a device for preventing a human body or the like from being caught).
[0002]
[Prior art]
  A safety device for an electric power window device is a part of a human body such as a finger, arm or head when a window glass is closed. A window frame (in a so-called sashless door vehicle without a window frame) Various systems have been disclosed so far for the purpose of realizing a pinching prevention function for preventing an accident that is pinched between a window glass and a vehicle interior roof portion close to the upper edge portion.
[0003]
  These disclosed methods can be broadly divided in principle.
(1)A type that monitors the drive current of a power window motor and detects an abnormal current waveform (occurrence of an overload current in the normal operating range) when pinching occurs and cancels the operation of the motor
(2)A type that monitors the rotation state of a power window motor as a pulse train, detects rotation pulse abnormality (occurrence of pulse train abnormality in the normal operation range) when pinching occurs, and cancels the operation of the motor
(3)A touch sensor is provided in the glass run channel part of the window frame that touches the upper edge of the window glass. When the window glass is closed, the touch sensor detects that a part of the human body such as a finger, arm, or head has been pinched. Type that cancels the operation of the motor
(4)A type in which a touch sensor is provided at the upper edge of the window glass, and the operation of the motor is canceled by detecting that a part of a human body such as a finger, arm, or head touches the touch sensor when the window glass is closed.
Etc.
[0004]
  As specific disclosure examples,(1)No. 6-335284, the above type(2)The type of this is disclosed in JP-A-5-321530, the above(3)No. 61-104221, the aforementioned type(4)Examples of this type include JP-A-60-119883.
[0005]
[Problems to be solved by the invention]
  However, among conventional safety devices,(1)When(2)In all of these types, a part of the human body such as fingers, arms, and heads is actually sandwiched between the window frame and the window glass, and the power window motor is not overloaded, and it is compressed. Because there is a response delay that cannot be removed, such as the operation delay of the relay that makes the motor differential, the inertia of the motor, the power supply voltage dependency of the motor output, etc. It was inevitable to give pain and discomfort to the person who was caught, and it was difficult to achieve its purpose completely as a safety device.
[0006]
  Plus this(1)When(2)When applying this type to various mass-produced vehicles, the load conditions on the motor are not the same due to differences in the size of the window, installation, etc., depending on the vehicle model. Evaluation or simulation is necessary, and much effort is required for development.
[0007]
  Also,(3)This type performs safety control by touching the touch sensor arranged in the window frame.If the contact to the touch sensor is actually sandwiched, the side visor is provided. , Before the contacted part touches the touch sensor of the window frame, it is strongly sandwiched by the side visor,(1)And(2)As in the case of this type, there is a possibility that it may be painful to a person who is caught before the safety operation functions, and it is not always sufficient as a safety device.
[0008]
  In particular,(3)In the disclosed example of this type, a capacitance type sensor is configured by embedding a conductive material in a glass run, and the sensor detects contact of a human body or the like and cancels the operation of the motor. The structure of the glass run is complicated and expensive, and the capacitive sensor disclosed here is used for capacitance detection.oscillationAnd fundamental frequencyoscillationTwo of the vesseloscillationBecause of the structure that detects the difference in frequencyoscillationVesseloscillationDue to frequency variation, temperature characteristics, and glass run material changes due to aging, electrostatic capacity drift due to cracks, etc., resulting in stable operation.LackIt was a thing.
[0009]
  Also,(4)This type performs safety control by touching the touch sensor installed at the upper edge of the window glass,(1),(2)as well as(3)Compared to this type, it is suitable as a safety device. However, the touch sensor has a structure in which an electrode is baked on the upper edge of the window glass, a pressure conductive rubber is disposed on the electrode, and further, these are sealed and coated with a transparent silicon rubber. And the formation thereof is complicated, and glass coating wiring is also required for taking out the sensor output.
[0010]
  further,(4)This type requires a plurality of touch sensors to be arranged along the upper edge of the window glass in order to make the detection area of the touch sensor correspond to the entire upper edge where the window glass is expected to be sandwiched. It was also something that took.
[0011]
  The present invention has been made in consideration of such technical problems. During the closing operation of the window glass, the window frame (the upper edge of the window when fully closed in a so-called sashless door vehicle without a window frame) is disclosed. When the proximity of a conductive object such as a human body is detected in the vicinity of the roof of the vehicle interior near the door window or the door window glass itself, the operation of the power window motor is performed without contact (before actually being pinched) The purpose of this invention is to realize a safety device that can be applied to all vehicle types that is inexpensive, stable, highly sensitive, and capable of mass production.Another object is to realize a sensor device suitable for such a safety device.
[0012]
[Means for Solving the Problems]
(A) In order to solve this problem, the invention described in claim 1, ElectricA phase delay type capacitive sensor device that detects a change in electrostatic characteristics in a space near the pole as a phase change of an electric signal includes the following means.
[0013]
  That is, (1) two pairs of electrodes arranged in the vicinity of the observation region, (2) a pulse generation circuit that generates a reference pulse, (3) a frequency dividing circuit that divides and outputs the reference pulse, and (4 ) Divide by divider circuitpulseThe resistance tap position of the variable terminal that inputs the signal can be displaced in an analog or digital manner by applying an electrical control signal, and the reference pulse input to the variable terminal can be branched and output to the two fixed terminals. Resistance means, (5) a switch control circuit that receives an intermediate pulse generated in the frequency dividing process of the frequency dividing circuit and generates a switch control signal based on the intermediate pulse, and (6) a switch based on the switch control signal. Dividing the element with high frequency and input from the divider circuitpulseThe first and second switch circuits for controlling the application to the subsequent stage circuit; and (7) one pair of electrodes to be connected among the two pairs of electrodes, and the first and second switch circuits. One of the two fixed terminals of the variable resistance means, and an integration circuit constituted by a resistance component between the fixed terminal to be connected and the variable terminal.Frequency division generated by the frequency dividerFirst and second variable delay circuits that integrate pulses and output phase delay timing pulses; and (8) relative changes in the phase relationship of the phase delay timing pulses output from the first and second variable delay circuits. And (9) a control means for outputting an electrical control signal for controlling the resistance tap position of the variable terminal of the variable resistance means.
[0014]
  Thus, the claim1In the invention described in (1), an integration circuit (a pair of electrodes) that makes it possible to control the resistance tap position of the variable terminal of the variable resistance means by means of an electrical control signal and constitutes the first and second variable delay circuits by the control circuit. The integration time (determined by the capacitance value and the resistance value) can be controlled, and the influence of aging and environmental changes can be achieved. Regardless of this, the relative phase relationship between the first and second variable delay circuits can always be maintained in an optimum state, and the frequency is divided into the first and second variable delay circuits.pulseCan be disconnected frequently by the first and second switch circuits, the time required for the integration time can be increased several times, and the detection sensitivity can be improved accordingly. Thus, it is possible to always detect a change in electrostatic characteristics occurring in the space near the pair of electrodes with high detection sensitivity.
[0015]
(B) The claim1The control means in the described invention inputs each phase delay timing pulse output from the first and second variable delay circuits, and switches and controls the resistance tap position of the variable terminal of the variable resistance means based on the delay time difference. It is desirable to be a thing.
[0016]
(CIn addition, it is further preferable that the control means in the invention described in claim 3 measures the delay time difference every fixed time and performs feedback control so that the delay time difference falls within the target range.
[0017]
(DIn addition, the control means according to the invention of claim 4 is arranged such that the resistance tap position indicated to the variable resistance means is large when the delay time difference is large with respect to the target range.DisplacementWhen the amount is increased and the distance from the target range of the delay time difference is small, the resistance tap position indicated to the variable resistance meansDisplacementIt is further desirable to reduce the amount.
[0018]
(EAnd claims5In the invention described in 1), the following means is provided in the phase-delay type capacitance sensor device that detects the change in the electrostatic characteristics in the space near the electrode as the phase change of the electric signal.
[0019]
  That is, (1) two pairs of electrodes arranged in the vicinity of the observation region, (2) a pulse generation circuit that generates a reference pulse, (3) a frequency dividing circuit that divides and outputs the reference pulse, and (4 ) A switch control circuit that generates a switch control signal based on the intermediate pulse generated in the frequency dividing process of the frequency divider, and (5) a switch element is frequently connected based on the switch control signal. Divided by frequency divider circuitpulseFirst and second switch circuits for controlling application to the subsequent stage circuit, (6) one pair of electrodes connected among the two pairs of electrodes, and a corresponding output among the first and second switch circuits First and second variable delay circuits that integrate a frequency-divided pulse generated by the frequency divider circuit by an integrating circuit composed of a resistance component connected to the output signal and output a phase delay timing pulse; (7) A phase discriminating circuit for discriminating a relative change in the phase relationship between the phase delay timing pulses output from the first and second variable delay circuits.
  Thus, the claim5In the invention described in (1), the frequency division into the first and second variable delay circuitspulseCan be disconnected frequently by the first and second switch circuits, the time required for the integration time can be increased several times, and the detection sensitivity can be improved accordingly. Thus, it is possible to always detect a change in electrostatic characteristics occurring in the space near the pair of electrodes with high detection sensitivity.
[0020]
(FAnd claims6In the invention according to claim 1, in a safety device that is mounted on an electric power window device that electrically drives the window glass to open and close, and prevents foreign objects from being caught during the window glass closing operation.5The capacitance sensor device according to any one of the above is provided as detection means.
[0021]
  By adopting such a configuration, it is possible to realize a safety device for an electric power window device with high detection sensitivity, excellent reliability, and high safety.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
(A) Overall configuration of electric power window device
  Embodiments of a safety device for a power window device according to the present invention will be described below with reference to the drawings. First, a functional block configuration of an electric power window device including the safety device will be described with reference to FIG.
[0023]
  As shown in FIG. 2, the electric power window device includes a phase delay type capacitance sensor 1, a control circuit 2, and a power window.UsThe switch (SW) operation unit 3, a power window drive circuit 4, and a motor 5 are included.
[0024]
  Among these, the phase delay type capacitive sensor 1 is an event (relative permittivity of water, human body, etc.) that changes the electrostatic characteristics generated in the vicinity of the capacitive sensor based on the relationship of the output phases of a plurality of capacitive sensors that form a pair. This is a means for detecting the approach of a large object) and is a core part of the safety device proposed in the present specification. The details of the phase delay type capacitive sensor 1 will be described later.
[0025]
  The control circuit 2 includes the output of the phase delay capacitance sensor 1 and a power window switch.Operation part3 is a means for controlling the opening / closing operation of the power window on the basis of the output of No. 3, and constitutes a safety device by the cooperative operation with the phase delay type capacitance sensor 1 described above. When the occurrence of an event such as pinching is detected from the output of the phase delay capacitive sensor 1, the control circuit 2 cancels (stops) the closing operation and performs an avoiding operation (an operation that reversely rotates the motor 5 by a predetermined amount). ). However, since various operations have already been considered for the avoidance operation as the safety device, it is possible to use them.
[0026]
  The power window SW operation unit 3 is an input unit that receives an operation (auto-up, auto-down, etc.) requested by the user for the power window in accordance with the operation. The power window driving circuit 4 is means for controlling the current applied to the motor in accordance with a control signal from the control circuit 2. The motor 5 actually drives the power windowThoughIt is a power source that gives the necessary external force.
[0027]
(B) First embodiment of safety device
  Hereinafter, a first embodiment of a safety device including the phase delay type capacitance sensor 1 and the control circuit 2 will be described.
[0028]
(B-1) Configuration of safety device
  FIG. 1 shows a functional block configuration example of the safety device according to the first embodiment. The safety device according to the present embodiment includes capacitance sensors 11 and 12, a pulse generation circuit 13, delay amount adjustment circuits 14 and 15, variable delay circuits 16, 17, 18, and 19, phase discrimination circuits 20 and 21, and , A switching control circuit 22, switching circuits 23 and 24, and a control circuit 2.
[0029]
(A) Capacitance sensors 11, 12
  Capacitance sensors 11 and 12 are means for detecting a possibility of pinching an object (such as a human body) having a high relative dielectric constant during the closing operation of the power window as a change in capacitance, and specifically, a pair of sensors. It consists of a capacitor | condenser arrange | positioned so that an electrode may oppose. 3 and 4 show examples of attaching the capacitance sensors 11 and 12 to the power window.
[0030]
  Here, FIG. 3 is an example in which a pair of sensor electrodes formed in a conductive film shape is attached along the upper edge of the window frame. In the figure, the upper edge of the window frame is divided into two areas,ToAmount sensor 11 at the rearToA quantity sensor 12 is provided. FIG. 4 is an example in which a pair of sensor electrodes formed in the shape of a transparent conductive film is attached along the upper edge of the window glass. In the figure, the upper edge of the window glass is divided into two areas,ToAmount sensor 11 at the rearToA quantity sensor 12 is provided. Both FIG. 3 and FIG.Capacitance sensorThe relative positional relationship before and after 11 and 12 may be switched.
[0031]
(B) Pulse generation circuit 13
  The pulse generation circuit 13YongIt is a means for generating a pulse necessary for electrically detecting a change in relative capacitance generated between the quantity sensors 11 and 12. Specifically, as shown in FIGS. 5 and 6, a Schmitt inverter 13A, a resistor 13B, and a capacitor 13C are connected so as to constitute an oscillation circuit. 5 is a specific circuit diagram corresponding to FIG. 1, and FIG. 6 is a schematic configuration diagram showing a specific circuit configuration of the delay amount adjusting circuits 14 and 15. In FIG.
[0032]
(C) Delay amount adjusting circuits 14 and 15
  The delay amount adjusting circuits 14 and 15 are means provided for enabling the creation of a sensitive detection sensitivity and automatic adjustment (trimming) of the secular change and environmental change (temperature, humidity, etc.) of the detection sensitivity. . Specifically, as shown in FIG. 6, a multistage control type electron whose position of the variable terminal of the resistor is displaced stepwise in response to application of a control signal.Volume14A and 15A.
[0033]
  In addition to the two fixed terminals (−) and (+) and one variable terminal, the electronic regulators 14A and 15A set the resistance dividing position by an electric signal.DisplacementTwo control terminals (+/− direction control terminals 14B, 15B and stepDisplacementTerminal 14C, 15C), and the distribution of the resistance value to the corresponding variable delay circuit 16, 17 or 18, 19 can be changed based on the control signal given from the control circuit 2 made of a microcomputer. It has become.
[0034]
  In this embodiment, the electronicVolumeThe position of the variable terminal as 14A, 15A is stepwise (digital) according to the application of the control signalDisplacementTo use, but analogDisplacementYou can also apply what you do.
[0035]
(D) Control circuit 2
  The control circuit 2 includes a program memory, a data memory, a timer, a counter, and the like for executing correction processing in a microcomputer that performs adjustment control of detection sensitivity, and is connected to each unit by the following signal lines a to f. ing.
[0036]
  The signal line a is a signal line (hereinafter referred to as “asig”) for notifying the control circuit 2 of the start timing of the delay operation of the variable delay circuits 4 and 5. The output of the pulse generation circuit 13 is given through this signal line a. The signal line b is a signal line (hereinafter referred to as “bsig”) for notifying the control circuit 2 of the timing of each delay output in the variable delay circuits 16 and 18. The signal line c is a signal line (hereinafter referred to as “csig”) for notifying the control circuit 2 of the timing of each delay output in the variable delay circuits 17 and 19. The signal line d is a signal line for notifying the control circuit 2 of each detection output of the phase discrimination circuits 20 and 21.
[0037]
  The signal lines e and f provide adjustment signals for keeping the sensitivity constant at all times.Delay amountThis is an output control line for giving to the adjustment circuits 14 and 15. Incidentally, the signal line e isDelay amountOf the electronic controls 14A and 15A in the adjusting circuits 14 and 15DisplacementOutput control line (+/-) for designating the direction. When the output from the control circuit 2 is at "H" level,DisplacementTo the (-) direction at the "L" levelDisplacementIs specified. The signal line f is a step of the electronic controls 14A and 15A.DisplacementOutput control line (inc) that controls the amount, one step in the direction specified by the signal line e for each pulse signal outputDisplacementTo do. Therefore, in the case of two-step movement, two pulse signals are continuously output.
[0038]
(E) Variable delay circuits 16, 17, 18, 19
  The variable delay circuits 16 and 17 areYongThis is a circuit for detecting the approach of an object (such as a human body) having a high relative dielectric constant to the quantity sensor 12, and the variable delay circuits 18 and 19 areYongThis is a circuit for detecting the approach of an object (such as a human body) having a high relative dielectric constant to the quantity sensor 11.
[0039]
  Here, the variable delay circuits 16 and 17 are integrating circuits.(YongQuantity sensors 11, 12 and resistors 16A, 17A andDelay amountAnd the Schmitt inverters 16B and 17B.YongThe output pulse of the pulse generation circuit 13 is delayed and output by an amount corresponding to the capacitance value in the quantity sensors 11 and 12.
[0040]
  On the other hand, the variable delay circuits 18 and 19 are integrated circuits.(YongQuantity sensors 12, 11 and resistors 18A, 19A andDelay amountAnd the Schmitt inverters 18B and 19B.YongThe output pulse of the pulse generation circuit 13 is delayed and output by an amount corresponding to the capacitance value in the quantity sensors 11 and 12.
[0041]
  The integration time (delay amount) of the variable delay circuits 16 and 18 is set slightly larger than the integration time (delay amount) of the corresponding variable delay circuits 16 and 19, respectively. This is an object with a high relative dielectric constant (human body, etc.)NoDue to the approach to the quantity sensor 11 or 12, the integration time (delay amount) of the variable delay circuit connected to the approached variable capacitance sensor is increased, and the phase relationship is reversed between the output pulses of the paired variable delay circuits. This is because the occurrence is detected as the approach of an object (such as a human body) having a high relative dielectric constant.
[0042]
  Accordingly, in order to increase the detection sensitivity, the relationship between the integration time (delay amount) in the normal state between the paired variable delay circuits 16 and 17 and 18 and 19 (integration time of the variable delay circuit 16> variable delay). The integration time (delay amount) is required to be as close as possible while maintaining the integration time of the circuit 17 and the integration time of the variable delay circuit 18> the integration time of the variable delay circuit 19.
[0043]
  In addition, in order to eliminate the possibility of deterioration in detection sensitivity and erroneous detection due to component characteristics and constant drift due to aging and environmental changes, it is necessary to satisfy the above conditions under any environment.
[0044]
  Therefore, in the present embodiment, a configuration is adopted in which the resistances assigned to the variable delay circuits 16, 17, 18 and 19 that are paired by the delay amount adjusting circuits 14 and 15 are automatically adjusted individually.
[0045]
(F) Phase discrimination circuits 20 and 21
  The phase discriminating circuits 20 and 21 are means for discriminating the phase relationship of output pulses between a pair of variable delay circuits (between 16 and 17, 18 and 19). When the phase of the output pulse of the variable delay circuit 17 is delayed compared to the phase of the output pulse of the variable delay circuit 16, that is, the phase discrimination circuit 20 is an object (such as a human body) having a high relative dielectric constant to the variable capacitance sensor 12. When an inversion of the phase relationship due to the approach of is detected, an output d of “H” level is output. On the other hand, when the phase of the output pulse of the variable delay circuit 19 is delayed compared to the phase of the output pulse of the variable delay circuit 18, the phase discrimination circuit 21, that is, Etc.), an output “d” of “H” level is output.
[0046]
  The phase discriminating circuits 20 and 21 include D-type flip-flops 20A and 21A that receive the output pulses from the variable delay circuits 16 and 18 as D inputs and the output pulses from the variable delay circuits 17 and 19 as clock inputs, and a noise elimination circuit. (Resistors 20B, 21B, capacitors 20C, 21C, Schmitt triggers 20D, 21D) and output buffer circuits (transistors 20E, 21E, resistors 20F, 21F).
[0047]
(G) Switching control circuit 22
  The switching control circuit 22YongThis is means for alternately connecting the quantity sensors 11 and 12 to the variable delay circuits 16 and 17 or the variable delay circuits 19 and 18 forming a pair. Here, the switching control circuit 22 includes a ½ divider circuit 22A that divides the output pulse of the pulse generation circuit 13 by ½, and an inverter that generates an inverted output thereof.
[0048]
  The switching control circuit 22 has a case where the output of the 1/2 divider circuit 22A is at “H” level and the output pulse of the pulse generation circuit 13 is at “L” level.YongThe charges accumulated in the quantity sensors 11 and 12 are discharged, and the inverter which prepares to enter the next detection operation by the variable delay circuits 18 and 19 and the output of the ½ divider circuit 22A are “L” level. Yes, and the output pulse of the pulse generation circuit 13 is at "L" levelYongThere is also provided an inverter that discharges the charges accumulated in the quantity sensors 11 and 12 and prepares to enter the next detection operation by the variable delay circuits 16 and 17.
[0049]
(H) Switching circuits 23 and 24
  The switching circuits 23 and 24 correspond to a control signal given from the switching control circuit 22.TheThis is means for switching a set of variable delay circuits (16, 17 or 18, 19) connecting the quantity sensors 11, 12. These switching circuits 23 and 24 are connected midpoints.ToIt consists of a pair of analog switches 23A, 23B, 24A, 24B to which the quantity sensors 11, 12 are respectively connected.
[0050]
  Here, the analog switches 23A and 24A are closed when the output of the switching control circuit 22 is at “H” level, and are opened when the output of the switching control circuit 22 is at “L” level. On the other hand, the analog switches 23B and 24B open when the output of the switching control circuit 22 is “H” level, and close when the output of the switching control circuit 22 is “L” level.
[0051]
(B-2) Operation of safety device
  Subsequently, the operation of the safety device according to the present embodiment will be described separately for each state.
[0052]
(A) Normal operation
  First, using FIG. 7 and FIG. 8, the operation in the case where no object having a high relative dielectric constant exists in the vicinity of any of the capacitive sensors 11 and 12 will be described. A pair of variable delay circuits 16,17It is assumed that the integration time (delay amount) is adjusted to an appropriate state by the delay amount adjustment circuit 14. Similarly, it is assumed that the integration time (delay amount) between the pair of variable delay circuits 18 and 19 is also adjusted to an appropriate state by the delay amount adjustment circuit 15.
[0053]
  The output pulse S1 generated in the pulse generation circuit 13 is given to the delay amount adjustment circuits 14 and 15 and the switching control circuit 22. Among these, the output pulse S1 given to the switching control circuit 22 is divided by 1/2 and is given to the switching circuits 23 and 24 as the switching control signal S2.
[0054]
  Here, the analog switches 23A and 24A of the switching circuits 23 and 24 are closed during the period when the switching control signal S2 of the switching control circuit 22 is at “H” level as shown in FIGS. 7 and 8 at the rising timing of the output pulse S1. The capacitive sensors 11 and 12 are connected to the variable delay circuits 16 and 17.
[0055]
  At this time, while the output pulse S1 is at the “H” level, as shown in FIGS. 7C and 7D and FIGS. 8C and 8D, the outputs S3 and S4 of the respective delay circuits are integrated time. It rises with a waveform corresponding to (delay amount).
[0056]
  Since the integration time (delay amount) of the variable delay circuit 16 is set larger than the integration time (delay amount) of the variable delay circuit 17, the rising phase of the output S3 of the delay circuit on the variable delay circuit 16 side is set. Is slightly delayed from the rising phase of the output S4 of the delay circuit on the variable delay circuit 17 side.
[0057]
  For this reason, as shown in FIGS. 7G and 7H, the output S7 of the Schmitt trigger 16B on the variable delay circuit 16 side is slightly delayed in phase from the output S8 of the Schmitt trigger 17B on the variable delay circuit 17 side. It will be. These two outputs S7 and S8 are both fed to the phase discrimination circuit 20. Here, the output S7 is given to the D input terminal of the D-type flip-flop 20A, and the output S8 is given to the clock input terminal of the D-type flip-flop 20A.
[0058]
  Here, since the timing at which the output S8 applied to the clock input terminal rises is earlier than the timing at which the output S7 rises as described above, the output S11 of “L” level is output from the phase discrimination circuit 20 to the control circuit 2. Is output.
[0059]
  Next, when the output pulse S1 falls to the “L” level while the switching control signal S2 remains at the “H” level, the switching control circuit 22 uses the inverter circuit to discharge the charges accumulated in the capacitance sensors 11 and 12. The control enters a preparation state for moving to the next detection operation by the variable delay circuits 18 and 19.
[0060]
  After that, when the output pulse S1 rises again, this time, the switching control signal S2 is switched to the “L” level, and the capacitance sensors 11 and 12 are switched to the state of being connected to the variable delay circuits 19 and 18. At this time, the analog switches 23B and 24B are closed.
[0061]
  Then, while the output pulse S1 is at the “L” level, the outputs S5 and S6 of each delay circuit are integrated as shown in FIGS. 7 (E) and (F) and FIGS. 8 (E) and (F). It rises with a waveform corresponding to the time (delay amount).
[0062]
  Of course, since the integration time (delay amount) of the variable delay circuit 18 is set to be larger than the integration time (delay amount) of the variable delay circuit 19, the rising phase of the output S5 of the delay circuit on the variable delay circuit 18 side. Is slightly delayed from the rising phase of the output S6 of the delay circuit on the variable delay circuit 19 side.
[0063]
  For this reason, the output S9 of the Schmitt trigger 18B on the variable delay circuit 18 side is slightly delayed in phase from the output S10 of the Schmitt trigger 19B on the variable delay circuit 19 side. These two outputs S9 and S10 are both fed to the phase discrimination circuit 21. Here, the output S9 is given to the D input terminal of the D-type flip-flop 21A, and the output S10 is given to the clock input terminal of the D-type flip-flop 21A.
[0064]
  Here, since the timing at which the output S10 applied to the clock input terminal rises is earlier than the timing at which the output S9 rises, as described above, the output S12 of “L” level is also output from the phase discrimination circuit 21. 2 is output.
[0065]
  As described above, the outputs S11 and S12 of the phase discriminating circuits 20 and 21 are both at the “L” level during normal operation. Based on the input result, the control circuit 2 can detect an object having a high relative dielectric constant. Make sure it is not near the upper edge of the power window glass or near the upper edge of the window frame.
[0066]
  When the output pulse S1 falls to the “L” level while the switching control signal S2 remains at the “L” level, the switching control circuit 22 controls the discharge of the charges accumulated in the capacitance sensors 11 and 12 using the inverter circuit. Then, a preparation state for moving to the next detection operation by the variable delay circuits 16 and 17 is entered.
[0067]
(B) Operation when an object having a high dielectric constant approaches the vicinity of the capacitive sensor 12
  Next, an operation when an object having a high dielectric constant approaches the vicinity of the capacitive sensor 12 will be described with reference to FIG. The operation in this case corresponds to the signal waveform in the right half portion of FIG. Also in this case, the basic operation is the same as that in the normal operation, and the pair of variable delay circuits connected to the capacitance sensors 11 and 12 is alternately switched by the switching control signal S2, and the output pulse S1 is " When the signal is at the “H” level, the phase relationship is detected.
[0068]
  The difference is that the capacitance of the capacitive sensor 12 increases as an object having a high relative permittivity approaches, and the integration time (delay amount) on the variable delay circuit 17 side and the integration time (delay amount) on the variable delay circuit 16 side. The reverse phenomenon occurs between the two. That is, it becomes like FIG.7 (C), (D).
[0069]
  As a result, as shown in FIGS. 7G and 7H, the output S8 of the Schmitt trigger 17B on the variable delay circuit 17 side is slightly delayed in phase from the output S7 of the Schmitt trigger 16B on the variable delay circuit 16 side. In other words, the output S8 given to the clock input terminal is at the rising timing, and the output S7 that has risen first is latched, so that the phase discrimination circuit 20 outputs the output S11 of “H” level to the control circuit 2. Become.
[0070]
  On the other hand, the relationship between the integration time (delay amount) on the variable delay circuit 18 side and the integration time (delay amount) on the variable delay circuit 19 side is rather because the capacitance sensor 12 is connected to the variable delay circuit 18 side. The difference in integration time (delay amount) increases. That is, it becomes like FIG.7 (E) and (F). Therefore, the phase discrimination circuit 21 is in a state in which the output S12 of “L” level is output to the control circuit 2 as in the normal operation.
[0071]
  Thus, when the output S11 of the phase discriminating circuit 20 is at the “H” level and the output S12 of the phase discriminating circuit 21 is at the “L” level, the control circuit 2 can detect the vicinity of the upper edge of the power window glass or the window frame. It is confirmed that an object having a high relative dielectric constant is present in the vicinity of the capacitive sensor 12 in the vicinity of the upper edge of. Note that, after the confirmation, the control circuit 2 instructs the power window driving circuit 4 to avoid pinching the object.
[0072]
(C) Operation when an object having a high relative dielectric constant approaches the capacitive sensor 11
  On the other hand, the operation when an object having a high relative dielectric constant approaches the vicinity of the capacitive sensor 11 will be described with reference to FIG. The operation in this case corresponds to the signal waveform in the right half portion of FIG. In this case, the basic operation is the same as that in the normal operation.
[0073]
  The difference is that the capacitance of the capacitive sensor 11 increases as an object having a high relative dielectric constant approaches, and the integration time (delay amount) on the variable delay circuit 19 side and the integration time (delay amount) on the variable delay circuit 18 side. The reverse phenomenon occurs between the two. That is, it becomes like FIG.7 (E) and (F).
[0074]
  As a result, as shown in FIGS. 7I and 7J, the output S10 of the Schmitt trigger 19B on the variable delay circuit 19 side is slightly delayed in phase from the output S9 of the Schmitt trigger 18B on the variable delay circuit 18 side. Therefore, the output S10 given to the clock input terminal is at the rising timing, and the output S9 that has risen first is latched, and the phase discrimination circuit 21 outputs the output S12 of “H” level to the control circuit 2. Become.
[0075]
  On the other hand, the relationship between the integration time (delay amount) on the variable delay circuit 16 side and the integration time (delay amount) on the variable delay circuit 17 side is rather because the capacitance sensor 11 is connected to the variable delay circuit 16 side. The difference in integration time (delay amount) increases. That is, it becomes like FIG.7 (C), (D). Accordingly, the phase discrimination circuit 20 is in a state in which the output S11 of “L” level is output to the control circuit 2 as in the normal operation.
[0076]
  Thus, when the output S11 of the phase discriminating circuit 20 is at the “L” level and the output S12 of the phase discriminating circuit 21 is at the “H” level, the control circuit 2 can detect the vicinity of the upper edge of the power window glass or the window frame. It is confirmed that an object having a high relative dielectric constant exists in the vicinity of the capacitive sensor 11 in the vicinity of the upper edge of the. Note that, after the confirmation, the control circuit 2 instructs the power window driving circuit 4 to avoid pinching the object.
[0077]
  When the outputs S11 and S12 of the phase discrimination circuits 20 and 21 are both at the “H” level, the control circuit 2 has an object with a high relative dielectric constant near the upper edge of the power window glass or the upper edge of the window frame. As a result, the power window drive circuit 4 is also instructed to avoid pinching the object.
[0078]
(D) Automatic adjustment (trimming) operation
  The above is the operation content when the integration time (delay amount) between the paired variable delay circuits 16 and 17 and between the variable delay circuits 18 and 19 is maintained in an appropriate state. However, the relative integration time (delay amount) between the variable delay circuits 16 and 17 and between the variable delay circuits 18 and 19 immediately after manufacture or immediately after setting is not in an optimum state due to the influence of variations in component constants. . For this reason, conventionally, it has been necessary to adjust (trim) the relative integration time (delay amount) individually for each unit.
[0079]
  Even if it is initially adjusted to the optimum state, the parts are affected by aging and environmental changes (temperature, humidity, etc.), and the characteristics and constants of the parts that make up the safety device drift and become relative. The relationship of integration time (delay amount) changes. As a result, the detection sensitivity may be reduced.
[0080]
  Therefore, in the safety device according to the present embodiment, the control circuit 2 monitors a shift in relative integration time (delay amount) generated in the phase delay capacitance sensor 1 and automatically before the operation as the safety device is started. The amount of deviation is corrected automatically.
[0081]
  For this reason, the control circuit 2 directly inputs the output pulse S1 of the pulse generation circuit 13 via the signal line a and detects the rising timing of the asig, thereby integrating the variable delay circuits 16, 17 and 18, 19. This is the start timing of time (delay amount) measurement start.
[0082]
  Further, the control circuit 2 branches and inputs the delay outputs S7, S8, S9, and S10 of the variable delay circuits 16, 17, and 18, 19 and discriminates the difference (phase difference) of each delay time from the start timing. To be detected (bsig and csig).
[0083]
  Further, the control circuit 2 inputs (ipt) the outputs S11 and S12 of the phase discriminating circuits 20 and 21 to the interrupt input terminal as detection outputs d, and executes the original sensor output determination process in the interrupt process. To do.
[0084]
  Hereinafter, the automatic adjustment (trimming) operation of the safety device will be described with reference to the flowcharts shown in FIGS. The processing operation is executed by the control circuit 2. The control circuit 2 reads the program at the time of power-on reset and starts processing.
[0085]
  First, the control circuit 2 initializes various settings in step S1, and then in step S2, the electronic circuitVolumeIs controlled to a predetermined initial position. After such setting operation, the control circuit 2 detects the timing at which the output pulse S1 of the pulse generation circuit 13 rises from “L” to “H” based on the change in the signal waveform appearing on the signal line a. Specifically, it is determined whether or not the output pulse S1 rises from “L” to “H” when step S3 is executed.
[0086]
  Here, if a positive result is obtained, the control circuit 2 proceeds to step S4 and starts the delay timer. On the other hand, if a negative result is obtained, the control circuit 2 proceeds to step S5 and outputs a signal appearing on the signal line c (the output of the variable delay circuit 17 when adjusting the relative relationship between the variable delay circuits 16 and 17). When adjusting the relative relationship between S8 and the variable delay circuits 18 and 19, it is determined whether or not the output S10) of the variable delay circuit 19 is at "H" level. This determination is performed to determine whether the current determination timing is before or after the rising timing of the output pulse S1.
[0087]
  That is, when a positive result is obtained, it can be determined that the delay timer has already started after the rise of the output pulse S1, whereas when a negative result is obtained. It can be determined that the delay timer has not yet started before the rise of the output pulse S1.
[0088]
  Here, it is assumed that a negative result is obtained in step S5. In this case, it means that the predetermined measurement timing has not yet arrived. Therefore, the control circuit 2 clears the value of the delay timer built in the circuit in step S6, and then proceeds to the above-described step S3. Return and execute the above operations.
[0089]
  Now, when the predetermined measurement timing comes (output pulse S1 rises from “L” to “H”) and the measurement of the delay timer starts, the control circuit 2 proceeds to step 7 and the current timing appears on the signal line b. It is determined whether or not it is the timing when the signal waveform rises from “L” to “H”.
[0090]
  Here, if a positive result is obtained, the control circuit 2 proceeds to step S8 and proceeds to step S8 to show the signal waveform appearing on the signal line b from the rising edge of the output pulse S1 (in the case of adjusting the relative relationship between the variable delay circuits 16 and 17). When adjusting the relative relationship between the output S7 of the variable delay circuit 16 and the variable delay circuits 18 and 19, the delay time Tab required until the output S9) of the variable delay circuit 18 rises from "L" to "H" is calculated. To do.
[0091]
  When the control circuit 2 obtains a negative result at step S7 or when the calculation at step S8 is completed, the control circuit 2 proceeds to step S9 and proceeds to step S7 described above.PlaceIn the same manner as described above, it is determined whether or not the current timing is the timing at which the signal waveform appearing on the signal line c rises from “L” to “H”.
[0092]
  Then, if an affirmative result is obtained, the control circuit 2 proceeds to step S10 and changes to the signal waveform appearing on the signal line c from the rising edge of the output pulse S1 (variable when adjusting the relative relationship between the variable delay circuits 16 and 17). When adjusting the relative relationship between the output S8 of the delay circuit 17 and the variable delay circuits 18 and 19, the delay time Tac required until the output S10) of the variable delay circuit 19 rises from “L” to “H” is calculated. .
[0093]
  It should be noted that the detection processing of the rising edges of the signal waveforms appearing on these signal lines b and c may be preceded, and monitoring is continued until both delayed outputs (rising edges) are recognized.
[0094]
  As described above, when a negative result is obtained in step S9 or when the calculation process of step 10 is completed, the control circuit 2 proceeds to step S11, and both the signal level of the signal line b and the signal level of the signal line c are obtained. Is at “H” level. This is a process for determining whether the measurement of the delay times Tab and Tab is completed.
[0095]
  Here, if a negative result is obtained, the control circuit 2 again performs the process of step S3.BackThe above processing is repeated until both the delay times Tab and Tab are obtained.
[0096]
  Eventually, when a positive result is obtained in step S11 and it is confirmed that both the delay times Tab and Tac for the pair of variable adjustment circuits 16, 17 or 18, 19 that are the current adjustment targets are obtained, the control circuit In step S12, the delay timer is cleared and the time difference between the delay times Tab and Tab is calculated as Tbc. The calculation result is saved in the data memory by the control circuit 2.
[0097]
  When the time difference Tbc is calculated in this way, the control circuit 2 determines whether or not the time difference Tbc has been calculated n times in step S14 in order to suppress the variation error of the time difference due to the influence of noise or the like. If a negative result is obtained in step S14, the control circuit 2 proceeds to step S16 and adjusts the feedback timing so as to enter the feedback loop for executing the processing from step S3 again.
[0098]
  That is, in step S16, the control circuit 2 waits for the feedback timing to step S3 until the timing suitable for the measurement of the delay times Tab and Tac (until the output pulse S1 becomes the “L” level).
[0099]
  Eventually, n time differences Tbc are calculated, and if a positive result is obtained in step S14, the control circuit 2 proceeds to step S15 and calculates an average value Tbc (av) of these n time differences Tbc1 to Tbcn. These waveform relationships are shown in FIG.
[0100]
  As described above, when the average value Tbc (av) of the time difference is obtained, the control circuit 2 determines whether the delay time adjustment amount in the delay amount adjustment circuit 14 is appropriate based on the calculated average value Tbc (av). No, how many electrons in which direction if inappropriateVolume14A or 15ADisplacementDetermine what to do.
[0101]
  The contents of the determination here and the correction operation to the electronic volume 14A or 15A are classified as follows according to the calculated average value Tbc (av). This relationship is shown in FIG.
[0102]
(1) When Tbc (av) ≦ 0
    → 2-step correction in the (+) direction
(2) When 0 <Tbc (av) ≦ target area lower limit value
    → 1 step correction in the (+) direction
(3) When target area lower limit value <Tbc (av) ≦ target area upper limit value
    → No correction
(4) When target area upper limit value <Tbc (av) ≦ target area over 1 value
    → 1 step correction in the (-) direction
(5)When target area over 1 value <Tbc (av) ≤ target area over 2 value
    → Two-step correction in the (-) direction
  As can be seen from FIG. 12, the correction operation by the control circuit 2 is feedback control that acts to always keep Tbc (av) within the target region, and the amount of deviation between one set and the target region is calculated. In the above, it works to change the strength of the feedback in accordance with the degree of the deviation amount so that the feedback amount is quickly fed back into the target area as the deviation amount becomes larger. Further, the correction operation by the control circuit 2 sufficiently slows the response speed of the feedback control with respect to the approach speed of the detection target substance.
[0103]
  The control circuit 2 executes the above-described processing as the processing in steps S17 to S24. However, the control circuit 2 does not always perform the processing, but periodically executes the processing at regular intervals according to the determination in step S25. As described above, when an object having a large relative permittivity actually approaches, the approach can be detected with high sensitivity without being affected by the correction control.
[0104]
(B-3) Effects in the embodiment
  As described above, by adopting the above-described configuration of the phase delay type capacitive sensor 1, it is possible to prevent variations in characteristics of components constituting the phase delay type capacitive sensor 1, changes over time, environmental changes, and the like. There is no need for manual sensitivity adjustment (trimming), and it has stable and high detection sensitivity.maintenanceA free phase delay type capacitance sensor can be realized.
[0105]
  Capacitance sensors 11 and 12 are arranged on the window frame of the power window or the upper edge of the window glass, and the change in capacitance of the capacitance sensors 11 and 12 during the (automatic) closing operation of the window glass is detected. An electronic power window device with a function to prevent the pinching of objects with a high relative dielectric constant, such as the human body,VolumeBy applying the above-described phase delay type capacitive sensor 1 adopting 14A and 15A, it is possible to always realize highly sensitive and stable detection of pinching prevention regardless of aging and environmental changes. Thus, a safer power window device can be realized.
[0106]
(C) Second embodiment of safety device
  Hereinafter, a second embodiment of the safety device composed of the phase delay type capacitive sensor 1 ′ and the control circuit 2 ′ will be described.
[0107]
(C-1) Configuration of safety device
  FIG. 13 shows a functional block configuration example of the safety device according to the second embodiment. 13 shows the same parts as those in FIG. 1 with the same reference numerals and the corresponding parts with corresponding reference numerals. The safety device according to the present embodiment includes capacitive sensors 11 and 12, a pulse generation circuit 13 ′, variable delay circuits 16, 17, 18, and 19, phase discrimination circuits 20 and 21, a switching control circuit 22, and a switching control circuit. The circuits 23 and 24, the frequency dividing circuit 25, the offset adjustment circuits 26 and 27, the switch control circuit 28, the switch circuits 29, 30, 31, and 32, and the control circuit 2 ′.
[0108]
  Hereinafter, only components different from those of the first embodiment will be described individually.
[0109]
(A) Pulse generation circuit 13 '
  As shown in FIG. 14, the basic configuration of the pulse generation circuit 13 ′ is the same as that of the pulse generation circuit 13 described in the first embodiment. The difference is that a high frequency pulse of 1000 times or more with respect to the frequency of the pulse output from the pulse generation circuit 13 is generated.
[0110]
(B) Frequency divider 25
  The frequency dividing circuit 25 receives the output pulse S11 (FIG. 15A) of the pulse generating circuit 13 'and has a frequency equivalent to that of the output pulse of the pulse generating circuit 13 described in the first embodiment. This circuit uses the pulse S16 (FIG. 15F) as its output. Note that the frequency dividing circuit 25 is an intermediate pulse (divided by 2, 4, or 8) S12 (FIG. 15B), S13 (FIG. 15C), S14 (FIG. D)) is output from the output terminals Q1, Q2, and Q3.
[0111]
(C) Offset adjustment circuits 26 and 27
  The offset adjustment circuits 26 and 27 are means provided for adjusting the offset of the integration time (delay amount) between the paired variable delay circuits 16 and 17 and between the variable delay circuits 18 and 19, The inside is composed of general variable resistors 26A and 27A.
[0112]
  The offset adjustment circuits 26 and 27 correspond to the delay amount adjustment circuits 14 and 15 in the first embodiment, and in the first embodiment, in order to improve the stability against aging and environmental changes. It is desirable to apply the delay amount adjusting circuits 14 and 15 described above.
[0113]
(D) Switch control circuit 28
  The switch control circuit 28 receives the intermediate pulses S12, S13, and S14 generated by the frequency dividing circuit 25 in the frequency dividing process, and controls the switch circuits 29, 30, 31, and 32 to be turned on and off (FIG. 15E). ). In this embodiment, the switch control circuit 28 includes a logical product (AND) circuit 28A. Therefore, the control pulse S15 output from the switch control circuit 28 rises to the “H” level at a rate of once every time the output pulse S11 rises eight times.
[0114]
(E) Switch circuits 29, 30, 31, 32
  The switch circuits 29, 30, 31, and 32 are means for inputting the control pulse S15 and closing the switch only while the control pulse S15 is at “H” level. That is, the divided pulse S16 is sent to the variable delay circuit once in 8 pulses of the output pulse S11.16, 17, 18 and 19 are applied. For this reason, the variable delay circuit16, 17, 18 and 19 are output in a staircase waveform as shown in FIG.
[0115]
(C-2) Operation of safety device
  Subsequently, the operation of the safety device according to the present embodiment will be described separately for each state.
[0116]
(A) Normal operation
  First, using FIG. 16 and FIG. 17, the operation in the case where an object having a high relative dielectric constant does not exist in the vicinity of any of the capacitive sensors 11 and 12 will be described. A pair of variable delay circuits 16,17It is assumed that the integration time (delay amount) is adjusted to an appropriate state by the offset adjustment circuit 26. Similarly, it is assumed that the integration time (delay amount) between the paired variable delay circuits 18 and 19 is also adjusted to an appropriate state by the offset adjustment circuit 27.
[0117]
  Now, in the pulse generation circuit 13 ′ in the present embodiment, the capacitor 13C ′ and the resistor 13B ′ constituting the circuit are compared with the capacitor 13C and the resistor 13B constituting the pulse generation circuit 13 in the first embodiment. It is set to a sufficiently small value. For this reason, the pulse period of the output pulse S11 output from the pulse generation circuit 13 ′ is the pulse generation circuit.13Compared to that, the high frequency output is 1000 times or more.
[0118]
  The high frequency output pulse S11 is input to the frequency dividing circuit 25. The frequency dividing circuit 25 has a multi-stage flip-flop circuit configuration, and the frequency dividing pulse S16 obtained by frequency dividing to a low frequency substantially equal to the output pulse of the pulse generating circuit 13 in the first embodiment is used as the offset adjusting circuits 26 and 27, and This is given to the switching control circuit 22.
[0119]
  Here, the switching control circuit 22 operates in the same manner as in the first embodiment, and provides the switching circuits 23 and 24 with a switching control signal S17 obtained by dividing the divided pulse S16 by 1/2. Thus, the analog switches 23A and 24A of the switching circuits 23 and 24 are closed during the period when the switching control signal S17 of the switching control circuit 22 is at “H” level as shown in FIGS. 16 and 17 at the rising timing of the divided pulse S16. The capacitive sensors 11 and 12 are connected to the variable delay circuits 16 and 17.
[0120]
  Therefore, also in the case of the present embodiment, as shown in FIGS. 16C and 16D and FIGS. 17C and 17D, the variable delay circuit while the divided pulse S16 is at the “H” level. The outputs S18 and S19 of the delay circuits 16 and 17 rise with waveforms corresponding to the integration time (delay amount), and a slight difference in the rising phase is detected by the phase discrimination circuit 20.
[0121]
  However, in the case of the present embodiment, as described with reference to FIG. 15, the application of the divided pulse S16 to the variable delay circuits 16 and 17 is performed in eight periods of the high-frequency output pulse S11 of the pulse generation circuit 13 ′. It will be intermittent only once.
[0122]
  For this reason, the integrated waveforms of the variable delay circuits 16 and 17 in this embodiment show charging characteristics when the intermittent control pulse S15 of the switch control circuit 28 is energized, as shown in FIG. On the other hand, when the intermittent control pulse S15 of the switch control circuit 28 is not energized, the integration characteristic changes so as to maintain the charge hold state.
[0123]
  This is equivalent to extending the integration time axis (FIG. 15G) of the variable delay circuits 16 and 17 when the switch control is not performed as in the conventional case to 8 times, and the variable delay circuit 16 in the conventional circuit. , 17 can be detected by expanding the slight difference in delay output timing by eight times to detect the phase relationship. That is, the detection sensitivity can be improved. Note that this is a variable delay circuit in the conventional circuit.16, 17This is equivalent to increasing the integration time constant of 8 times.
[0124]
  Thus, the phase discrimination circuit 20 discriminates the phase relationship between the outputs of the variable delay circuits 16 and 17 with an accuracy of 8 times. In this case, the output S26 of “L” level is output to the control circuit 2. It will be.
[0125]
  When the output pulse S1 falls to the “L” level while the switching control signal S2 remains at the “H” level, the charges accumulated in the capacitive sensors 11 and 12 are discharged by the switching control circuit 22, and the variable delay circuit 18, Then, the next detection operation by 19 is started.
[0126]
  Next, when the divided pulse S16 rises again, this time, the switching control signal S17 is switched to the “L” level, and the capacitance sensors 11 and 12 are switched to a state where they are connected to the variable delay circuits 19 and 18. The subsequent operation is the same as that shown in FIGS. 16E and 16F and FIGS. 17E and 17F except that the integrated waveforms appearing in the variable delay circuits 19 and 18 are stepped. This is the same as the first embodiment.
[0127]
(B) Operation when an object having a high dielectric constant approaches the vicinity of the capacitive sensor 12
  In this case, as shown in the signal waveform in the right half part of FIG. 16, the capacitance of the capacitive sensor 12 increases due to the approach of an object having a high relative dielectric constant, and the integration time (on the variable delay circuit 17 side) The reverse phenomenon occurs between the delay amount) and the integration time (delay amount) on the variable delay circuit 16 side, while the integration time (delay amount) on the variable delay circuit 19 side and the integration time (delay amount on the variable delay circuit 18 side). ) Causes a phenomenon in which the integration time difference further increases.
[0128]
  In this embodiment, a reverse phenomenon between the integration time (delay amount) on the variable delay circuit 17 side and the integration time (delay amount) on the variable delay circuit 16 side is detected with an accuracy eight times that of the conventional circuit. Will do.
[0129]
  As a result, the control circuit 2 confirms that an object having a high relative dielectric constant exists in the vicinity of the capacitive sensor 12 in the vicinity of the upper edge of the power window glass or the upper edge of the window frame, and prevents the object from being caught. The window drive circuit 4 is commanded.
[0130]
(C) Operation when an object having a high relative dielectric constant approaches the capacitive sensor 11
  In this case, as shown in the signal waveform in the right half part of FIG. 17, the capacitance of the capacitive sensor 11 increases due to the approach of an object having a high relative dielectric constant, and the integration time (on the variable delay circuit 19 side) The reverse phenomenon occurs between the delay amount) and the integration time (delay amount) on the variable delay circuit 18 side, while the integration time (delay amount) on the variable delay circuit 16 side and the integration time (delay amount) on the variable delay circuit 17 side are generated. ) Causes a phenomenon in which the integration time difference further increases.
[0131]
  In this embodiment, a reverse phenomenon between the integration time (delay amount) on the variable delay circuit 19 side and the integration time (delay amount) on the variable delay circuit 18 side is detected with an accuracy eight times that of the conventional circuit. Will do.
[0132]
  As a result, the control circuit 2 confirms that an object having a high relative dielectric constant exists in the vicinity of the capacitive sensor 11 in the vicinity of the upper edge of the power window glass or the upper edge of the window frame, and prevents the object from being caught. The window drive circuit 4 is commanded.
[0133]
(C-3) Effects in the embodiment
  As described above, by setting the configuration of the phase delay type capacitive sensor 1 ′ as described above, it is possible to realize a phase delay type capacitive sensor having a detection sensitivity much higher than that of the conventional one.
[0134]
  Capacitance sensors 11 and 12 are arranged on the window frame of the power window or the upper edge of the window glass, and the change in capacitance of the capacitance sensors 11 and 12 during the (automatic) closing operation of the window glass is detected. By applying the above-described phase delay type capacitance sensor 1 to the safety device of the electric power window device having the function of preventing the object such as the human body having a high relative dielectric constant, it is possible to prevent the object from being pinched with high sensitivity and stability. Detection can be realized. Thus, a safer power window device can be realized.
[0135]
(D) Other embodiments
  In the first and second embodiments described above, the case where two capacitive sensors are used has been described, but the present invention can also be applied to the case where three or more capacitive sensors are used.
[0136]
  In the second embodiment described above, the frequency of the output pulse in the pulse generation circuit 13 ′ is set to 1000 times or more than the output pulse of the pulse generation circuit 13 in the first embodiment. Accordingly, a smaller magnification may be used.
[0137]
  In the above-described second embodiment, the case where the intermediate pulse output from the frequency divider 25 to the switch control circuit 28 is three types of signals, ie, frequency divided by 2, 4, and 8 is described. However, an intermediate pulse having a frequency of 16 or more may be given. Further, a combination of intermediate pulses can be freely selected.
[0138]
  In the first and second embodiments described aboveLeaveAre two processing circuits (a delay amount adjustment circuit, a variable delay circuit, a phase) for detecting the approach of an object having a high relative dielectric constant to the capacitive sensor 11 and for detecting the approach of an object having a high relative dielectric constant to the capacitive sensor 12. Although the case where a discrimination circuit (first embodiment), an offset adjustment circuit, a switch circuit, a variable delay circuit, and a phase discrimination circuit (second embodiment) are prepared is described, only one system is used as such a processing circuit. It is also possible to prepare and switch the connection relationship of the capacitance sensors 11 and 12 to the processing circuit alternately.
[0139]
  In the first and second embodiments described above, the case where the phase-delay type capacitive sensor 1 or 1 ′ is applied to a power window safety device has been described. (Including slide operation) It can be widely applied to a safety device in a device having a mechanism.
[0140]
  As described in the above description of the second embodiment, if the automatic adjustment (trimming) function in the first embodiment is combined with the second embodiment, it is possible to prevent changes over time and environmental changes. A safe and highly safe safety device (phase delay type capacitive sensor device) that has a very high detection sensitivity can be realized.
[0141]
【The invention's effect】
(A) According to the invention described in claim 1 as described above., ElectricIn a phase-delay type capacitive sensor device that detects changes in electrostatic properties in the space near the pole as changes in the phase of the electrical signal, the resistance tap position of the variable terminal of the variable resistance means can be controlled by the electrical control signal. In addition to the configuration in which the integration time of the integration circuit constituting the first and second variable delay circuits can be controlled by the circuit, frequency division into the first and second variable delay circuitspulseThe first and second switch circuits can be disconnected frequently, so that the relative phase of the first and second variable delay circuits is always maintained regardless of the influence of aging and environmental changes. The relationship can be maintained in an optimum state, and the detection sensitivity can be improved by extending the time required for the integration time several times.
[0142]
(BAnd claims as described above2According to the invention described in claim 1, the phase delay timing pulses output from the first and second variable delay circuits are input as the control means in the invention described in claim 1, and the variable resistance is determined based on the delay time difference. By using the one that switches and controls the resistance tap position of the variable terminal of the means, it is possible to reliably cancel the relative change in the delay time difference generated in the first and second variable delay circuits due to the influence of the secular change and the environmental change.
[0143]
(CAnd claims3According to the invention described in claim2As the control means in the invention described in the above, the relative delay time difference can always be kept constant by measuring the delay time difference every fixed time and performing feedback control so that the delay time difference falls within the target range. .
[0144]
(DAnd claims4According to the invention described in claim3As a control means in the invention described in (2), when the distance from the target range of the delay time difference is large, the resistance tap position indicated to the variable resistance meansDisplacementWhen the amount is increased and the distance from the target range of the delay time difference is small, the resistance tap position indicated to the variable resistance meansDisplacementBy using the one that reduces the amount, the delay time difference can be corrected within the target range in a short time.
[0145]
(EAnd claims as described above5According to the invention described in the above, in the phase delay type capacitance sensor device that detects the change in the electrostatic characteristics in the space near the electrode as the phase change of the electric signal, the frequency division into the first and second variable delay circuitspulseCan be disconnected frequently by the first and second switch circuits, the time required for the integration time can be increased several times, and the detection sensitivity can be improved accordingly.
[0146]
(FAnd claims as described above6According to the invention described in the above, in the safety device that is mounted on the electric power window device that electrically opens and closes the window glass and prevents foreign matter from being caught during the window glass closing operation,5By providing the capacitance sensor device according to any one of the above as a detection means, it is possible to realize a safety device for an electric power window device having high detection sensitivity and high reliability and high safety.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing a safety device (first embodiment) of an electric power window device.
FIG. 2 is a functional block diagram showing a schematic configuration of the electric power window device.
FIG. 3 is a diagram showing an example (part 1) of attaching a capacitance sensor to a power window.
FIG. 4 is a diagram showing an example (part 2) of attaching a capacitance sensor to a power window.
FIG. 5 is a circuit configuration diagram showing a safety device (first embodiment) of the electric power window device.
FIG. 6 is a circuit configuration diagram of a delay amount adjusting circuit and its peripheral circuits.
7 is a diagram showing signal waveforms at normal times and when an object having a high relative dielectric constant approaches the capacitance sensor 12. FIG.
FIG. 8 is a diagram showing signal waveforms at normal times and when an object having a high relative dielectric constant approaches the capacitance sensor 11;
FIG. 9 is a flowchart (No. 1) showing an automatic adjustment (trimming) operation execution program;
FIG. 10 is a flowchart (part 2) showing an automatic adjustment (trimming) operation execution program;
FIG. 11 is a diagram illustrating the principle of adjusting the offset amount.
FIG. 12 is a diagram illustrating a relationship between a detection amount and an adjustment amount.
FIG. 13 is a functional block diagram showing a safety device (second embodiment) of an electric power window device.
FIG. 14 is a circuit configuration diagram showing a safety device (second embodiment) of the electric power window device.
FIG. 15 is a diagram illustrating a relationship between an output pulse of a pulse generation circuit and a signal waveform of each unit.
FIG. 16 is a diagram showing signal waveforms at normal times and when an object having a high relative dielectric constant approaches the capacitive sensor 12;
FIG. 17 is a diagram illustrating signal waveforms at normal time and when an object having a high relative dielectric constant approaches the capacitance sensor 11;
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1, 1 '... Phase delay type capacitance sensor 2, 2' ... Control circuit, 3 ... Power windowUsSwitch (SW) operation unit 3, 4 ... power window drive circuit, 5 ... motor, 11, 12 ... capacitance sensor, 13, 13 '... pulse generation circuit, 14, 15 ... delay amount adjustment circuit, 16, 17, 18, DESCRIPTION OF SYMBOLS 19 ... Variable delay circuit 20, 21 ... Phase discrimination circuit, 22 ... Switching control circuit, 23, 24 ... Switching circuit, 25 ... Dividing circuit, 26, 27 ... Offset adjustment circuit, 28 ... Switch control circuit, 29, 30 31 and 32 are switch circuits.

Claims (6)

In a phase-delay type capacitive sensor device that detects a change in electrostatic characteristics in a space near an electrode as a phase change of an electrical signal,
Two pairs of electrodes arranged in the vicinity of the observation region;
A pulse generation circuit for generating a reference pulse;
A frequency dividing circuit for dividing and outputting the reference pulse;
The resistance tap position of the variable terminal to which the frequency dividing pulse is input from the frequency dividing circuit can be displaced in an analog or digital manner by applying an electric control signal, and two frequency dividing pulses input to the variable terminal Variable resistance means for branching and outputting to a fixed terminal;
A switch control circuit which receives an intermediate pulse generated in the frequency dividing process of the frequency divider circuit and generates a switch control signal based on the intermediate pulse;
First and second switch circuits that connect and disconnect the switch elements at a high frequency based on the switch control signal, and control application of a divided pulse input from the divider circuit to a subsequent circuit;
One of the two pairs of electrodes and one of the two fixed terminals of the variable resistance means connected via the first or second switch circuit and connected, The first and second outputs of the phase lag timing pulse by integrating the frequency- divided pulse generated by the frequency- dividing circuit by an integrating circuit composed of the fixed terminal and the resistance between the variable terminal. Variable delay circuit of
A phase discrimination circuit that discriminates a relative change in the phase relationship between the phase delay timing pulses output from the first and second variable delay circuits;
And a control means for outputting an electrical control signal for controlling a resistance tap position of a variable terminal of the variable resistance means. The capacitance sensor device according to claim 1 ,
The control means inputs each phase delay timing pulse output from the first and second variable delay circuits, and switches and controls the resistance tap position of the variable terminal of the variable resistance means based on the delay time difference. Capacitance sensor device characterized by the above. The capacitance sensor device according to claim 2 ,
The electrostatic capacity sensor device, wherein the control means measures the delay time difference every predetermined time and performs feedback control so that the delay time difference falls within a target range. The capacitance sensor device according to claim 3 .
The control means increases the displacement amount of the resistance tap position instructed to the variable resistance means when the distance from the target range of the delay time difference is large, and the variable resistance means when the distance from the target range of the delay time difference is small. A capacitance sensor device characterized by reducing a displacement amount of a resistance tap position instructed to In a phase-delay type capacitive sensor device that detects a change in electrostatic characteristics in a space near an electrode as a phase change of an electrical signal,
Two pairs of electrodes arranged in the vicinity of the observation region;
A pulse generation circuit for generating a reference pulse;
A frequency dividing circuit for dividing and outputting the reference pulse;
A switch control circuit which receives an intermediate pulse generated in the frequency dividing process of the frequency divider circuit and generates a switch control signal based on the intermediate pulse;
First and second switch circuits that connect and disconnect the switch elements at a high frequency based on the switch control signal, and control application of a divided pulse input from the divider circuit to a subsequent circuit;
Generated in the frequency divider circuit by an integrating circuit composed of a pair of electrodes connected between the two pairs of electrodes and a resistance component connected to a corresponding output of the first and second switch circuits. First and second variable delay circuits that integrate the divided pulse and output a phase delay timing pulse;
And a phase discrimination circuit that discriminates a relative change in the phase relationship between the phase delay timing pulses output from the first and second variable delay circuits. In a safety device that is mounted on an electric power window device that electrically drives the window glass to open and close, and prevents foreign objects from being caught during the window glass closing operation,
A safety device for an electric power window device comprising the capacitance sensor device according to any one of claims 1 to 5 as detection means.

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