Abstract: A capacitance type occupant sensor includes an electrostatic sensing unit, a reference electrode, a voltage applying portion, a current sensing portion, a capacitance calculating portion, and a discriminating portion. The reference electrode is applied with a reference potential. The electrostatic sensing unit is disposed in a vehicle seat, and includes a main electrode, a guard electrode and a noise electrode. The guard electrode is disposed adjacent to a lower side of the main electrode and applied with the reference potential. The noise electrode is disposed adjacent to a lower side of the guard electrode. The voltage applying portion applies a detection voltage to the main electrode and the noise electrode. The current sensing portion senses a main current of the main electrode, and a noise current of the noise electrode. The capacitance calculating portion calculates a first capacitance based on the detection voltage, the main current, and the noise current.

Abstract: A capacitance type occupant sensor includes an electrostatic sensing unit, a reference electrode, a voltage applying portion, a current sensing portion, a capacitance calculating portion, and a discriminating portion. The reference electrode is applied with a reference potential. The electrostatic sensing unit is disposed in a vehicle seat, and includes a main electrode, a guard electrode and a noise electrode. The guard electrode is disposed adjacent to a lower side of the main electrode and applied with the reference potential. The noise electrode is disposed adjacent to a lower side of the guard electrode. The voltage applying portion applies a detection voltage to the main electrode and the noise electrode. The current sensing portion senses a main current of the main electrode, and a noise current of the noise electrode. The capacitance calculating portion calculates a first capacitance based on the detection voltage, the main current, and the noise current.

Abstract: A capacitance type occupant detection sensor includes (i) a capacitive sensor, (ii) a voltage application portion, (iii) a current detector, (iv) a capacitance detector, and (v) a determination portion. The capacitive sensor includes a detection electrode and is disposed to a seat. The voltage application portion applies a detection voltage to the detection electrode, and provides an electric field between the detection electrode and a reference electrode, which is applied with a reference voltage. The current detector detects a current, which is provided by the detection voltage, flowing through the detection electrode. The capacitance detector detects a capacitance between the detection electrode and the reference electrode. The determination portion determines an occupant. The capacitive sensor has a first charging electrode and a second charging electrode. The first charging electrode is disposed apart from the detection electrode and applied with a charging voltage from the voltage application portion.

Abstract: A control circuit identifies whether an occupant on a seat is an adult or a child based on a first capacitance between a first sensing electrode and a ground and a second capacitance between a second sensing electrode and the ground. The first capacitance is computed based on a value of an electric current, which is supplied to the first sensing electrode at the time of applying an oscillation signal from a signal application circuit to the first sensing electrode. The second capacitance is computed based on a value of an electric current, which is supplied to the second sensing electrode at the time of applying an oscillation signal from the signal application circuit to the second sensing electrode.

Abstract: A capacitive occupant detection apparatus comprising a sensor unit and a control unit is disclosed. The sensor unit includes a detection electrode and a periphery guard electrode. The control unit includes: a signal application circuit for applying an oscillation signal to the detection electrode; an operational amplifier for applying to the guard electrode a signal having the same phase and potential as the oscillation signal applied to the detection electrode; and a control circuit for receiving current and voltage values supplied to the detection and for determining a mounting state on a seat based on the inputted current and voltage values (including phase information). The periphery guard electrode is located to surround the detection electrode when viewed from an upper side of the detection electrode.

Abstract: An occupant detection device has an electrostatic sensor and a reference sensor device, which are disposed in a seat of a vehicle. The electrostatic sensor includes a detection electrode for generating a capacitance in a space defined by itself and a vehicle body. The reference sensor device has the same detection characteristic as the electrostatic sensor, and is arranged such that it is not affected by a liquid. An occupant determination unit of the detection device determines a presence of an occupant on the seat based on an output of the electrostatic sensor. A determination standard change unit of the detection device changes an occupant determination threshold based on an output of the reference sensor device, where the occupant determination threshold is used by the occupant determination unit for determining the presence of the occupant.

Abstract: An electrostatic sensor for a vehicle includes a loop-shaped electrode arranged in a seat bottom of the vehicle, and a sensor portion to detect a weak electric field generated between the electrode and a chassis of the vehicle when a predetermined voltage is applied to the electrode. The electrode has an imaginary center line linearly extending in a front-and-rear direction of the vehicle. The electrode defines a resistance distribution approximately symmetrical in a left-and-right direction of the vehicle relative to the imaginary center line.

Abstract: A capacitive occupant detecting apparatus includes a voltage applying portion, a capacitance sensor, a capacitor, a storing portion, a measuring portion, and a calculating portion. The voltage applying portion applies an alternating-current voltage signal to the capacitance sensor and the capacitor. The storing portion stores a reference voltage. The measuring portion detects a first voltage in accordance with an electric current that flows between the voltage applying portion and the capacitor when the alternating-current voltage signal is applied to the capacitor. The measuring portion detects a second voltage in accordance with an electric current output from the capacitance sensor when the alternating-current voltage is applied to the capacitance sensor. The calculating portion detects an abnormality of the voltage applying portion based on the first voltage and the reference voltage, and determines an object disposed on the seat based on the second voltage.

Abstract: A main electrode is located in a vehicle seat. A guard electrode is located between a grounded vehicle body and the main electrode. A detection unit selectively applies an alternating voltage signal to the main electrode and the guard electrode, sets the main electrode and the guard electrode to be in an open state or a grounded state, detects an electric current of one of the main electrode and the guard electrode, converts the selected electric current into a voltage value, and detects an overcurrent in the main electrode and the guard electrode. A control unit determines the main electrode and the guard electrode to be an open failure, a power supply short failure, a grounded failure, or a short failure with the guard electrode, according to one or a combination of the voltage value and detection or non-detection of an overcurrent.

Abstract: A capacitive passenger detector includes: a capacitive sensor having main, sub and guard electrodes; a sensor characteristic measurement unit for applying an alternating voltage signal to each electrode and for converting a current in each electrode to a voltage; and a controller. The controller defines a current in the guard electrode as a reference current when voltages of the main and guard electrodes have a same potential. The controller defines a current flowing direction of the guard electrode to be negative when the voltage of the main electrode is higher than the guard electrode. The controller defines the current flowing direction of the guard electrode to be positive when the voltage of the main electrode is lower than the guard electrode. The controller corrects the voltage of the main electrode based on the current of the guard electrode so that a corrected voltage is set to be a passenger determination data.

Abstract: A sensor detection controller is used in combination with a capacitive sensor that is mounted on a seat of a vehicle in such a manner that a capacitance of the capacitive sensor changes according to whether the seat is occupied. The sensor detection controller has a fault detection mode and a normal detection mode. The sensor detection controller includes a signal source for applying an amplitude signal to the capacitive sensor, a switch for switching a signal path, through which the amplitude signal is applied, between the fault detection mode and the normal detection mode, a signal detector for detecting a change in a voltage or a current of the amplitude signal when the amplitude signal is applied, and an impedance member connected to the signal path.

Abstract: An occupant detection sensor for detecting an occupant seating state on a seat comprises: a contact pressure sensor section including a pair of opposed electrodes arranged parallel to a seating face part of the seat; an electrostatic sensor section including a main electrode arranged parallel to the seating face part of the seat and a guard electrode arranged between the main electrode and a seat frame, the guard electrode and the main electrode having a same electric potential; a capacitance measuring section for measuring a first capacitance between the opposed electrodes and a second capacitance between the main electrode and ground; and an occupant distinguishing section for distinguishing a seating state of the occupant based on the first capacitance and the second capacitance.

Abstract: A capacitive occupant sensor for detecting an occupant sitting on a seat cushion of a seat of a vehicle includes a capacitive sensor mat, a cushion member, and a floating electrode. The capacitive sensor mat is disposed in the seat cushion and has a surface. The cushion member is disposed on the surface of the capacitive sensor mat. The floating electrode is disposed on an opposite side of the cushion member from the surface of the capacitive sensor mat. A projected area of the floating electrode with respect to the surface is smaller than the surface. The floating electrode is in an electrically-floating state with respect to the capacitive sensor mat. The occupant is detected based on an occupant capacitance between the capacitive sensor mat and the occupant and a floating capacitance between the capacitive sensor mat and the floating electrode.

Abstract: An occupant detection apparatus for a vehicle is disclosed. The occupant detection apparatus includes a buckle switch, a seat position sensor and an electronic control unit. The electronic control unit includes a first active element and a second active element that respectively control energization of the buckle switch and the seat position sensor. The electric control unit performs on-off control on the first active element in such manner that: the first active element is held on for a predetermined period; and at a time of an end of the predetermined period, the first active element is switched off and the second active element is switched on. The occupant detection apparatus can reduce radio noise generated due to the energization of the buckle switch and the seat position sensor, and can minimize an influence of the radio noise on another electronic apparatus mounted in the vehicle.

Abstract: A capacitive occupant detection apparatus comprising a sensor unit and a control unit is disclosed. The sensor unit includes a detection electrode and a periphery guard electrode. The control unit includes: a signal application circuit for applying an oscillation signal to the detection electrode; an operational amplifier for applying to the guard electrode a signal having the same phase and potential as the oscillation signal applied to the detection electrode; and a control circuit for receiving current and voltage values supplied to the detection and for determining a mounting state on a seat based on the inputted current and voltage values (including phase information). The periphery guard electrode is located to surround the detection electrode when viewed from an upper side of the detection electrode.

Abstract: A control circuit identifies whether an occupant on a seat is an adult or a child based on a first capacitance between a first sensing electrode and a ground and a second capacitance between a second sensing electrode and the ground. The first capacitance is computed based on a value of an electric current, which is supplied to the first sensing electrode at the time of applying an oscillation signal from a signal application circuit to the first sensing electrode. The second capacitance is computed based on a value of an electric current, which is supplied to the second sensing electrode at the time of applying an oscillation signal from the signal application circuit to the second sensing electrode.

Abstract: A sensor detection controller is used in combination with a capacitive sensor that is mounted on a seat of a vehicle in such a manner that a capacitance of the capacitive sensor changes according to whether the seat is occupied. The sensor detection controller has a fault detection mode and a normal detection mode. The sensor detection controller includes a signal source for applying an amplitude signal to the capacitive sensor, a switch for switching a signal path, through which the amplitude signal is applied, between the fault detection mode and the normal detection mode, a signal detector for detecting a change in a voltage or a current of the amplitude signal when the amplitude signal is applied, and an impedance member connected to the signal path.

Abstract: In a method of adjusting an electrostatic occupant detecting apparatus, a first group of load circuits is coupled with a sensor property measuring device, an AC voltage signal is applied from a signal source to the first group of load circuits, and a potential difference generating at a resistor of the sensor property measuring device is stored as a first measured value. A second group of load circuits having a load higher than the first group is coupled with the sensor property measuring device, the AC voltage signal is applied from the signal source to the second group of load circuits, and a potential difference generating at the resistor is stored as a second measured value. A measured sensitivity is calculated from the first measured value and the second measured value, and a sensitivity adjusting value is calculated from the measured sensitivity and an ideal sensitivity.

Abstract: An occupant detection apparatus includes a capacitive sensor, a signal applying circuit, a signal detector, and a voltage applying circuit. The capacitive sensor has an electrode. The signal applying circuit applies a voltage amplitude signal to the electrode during a first time period, but does not apply the voltage amplitude signal to the electrode during a second time period. The voltage amplitude signal has a voltage with a varying amplitude. The signal detector detects a change in an electric current flowing through the capacitive sensor during the first time period. The voltage applying circuit applies a predetermined voltage to the electrode during the entire first time period and during at least part of the second time period.

Abstract: A capacitive occupant sensor for detecting an occupant sitting on a seat cushion of a seat of a vehicle includes a capacitive sensor mat, a cushion member, and a floating electrode. The capacitive sensor mat is disposed in the seat cushion and has a surface. The cushion member is disposed on the surface of the capacitive sensor mat. The floating electrode is disposed on an opposite side of the cushion member from the surface of the capacitive sensor mat. A projected area of the floating electrode with respect to the surface is smaller than the surface. The floating electrode is in an electrically-floating state with respect to the capacitive sensor mat. The occupant is detected based on an occupant capacitance between the capacitive sensor mat and the occupant and a floating capacitance between the capacitive sensor mat and the floating electrode.