Passenger detection system
First Claim
1. A passenger detection system comprising:
- an antenna electrode which is provided to a portion of a vehicle located in front of a seat of a vehicle so as to face a passenger seated on the seat and generates an electric field between the antenna electrode and the passenger;
an oscillation means electrically connected to the antenna electrode, said oscillation means generating a high frequency low voltage oscillation signal in order to generate a weak electric field around the antenna electrode;
a current detection means for detecting a current which passes between the oscillation means and the antenna electrode depending on disturbance in the electric field between the antenna electrode and the passenger; and
a judgment means for judging a distance between the passenger and the portion of the vehicle based on the current detected by the current detection means.
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Accused Products
Abstract
A passenger detection system comprises an antenna electrode which is provided to the dashboard of a car, an oscillation circuit for generating a high frequency low voltage oscillation signal in order to generate a weak alternating electric field around the antenna electrode, a current detection section for detecting a transmission current which passes between the oscillation circuit and the antenna electrode depending on the weak alternating electric field which is generated around the antenna electrode, a phase difference detection section for detecting the phase difference between the oscillation signal supplied from the oscillation circuit and an output signal which is supplied to the antenna electrode, and a control circuit for judging the presence or absence of a passenger seated on the seat based on the detected phase difference and judging the distance between the passenger and the dashboard based on the detected transmission current. The passenger detection system is connected with an air bag unit, and the air bag unit is set at a ‘no deployment mode’ if it is judged that no passenger is seated on the seat or the distance between the passenger and the dashboard is less than a minimum allowable distance, thereby the passenger who is close to the dashboard is protected from secondary injury due to strong deployment of the air bag.
28 Citations
25 Claims
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1. A passenger detection system comprising:
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an antenna electrode which is provided to a portion of a vehicle located in front of a seat of a vehicle so as to face a passenger seated on the seat and generates an electric field between the antenna electrode and the passenger;
an oscillation means electrically connected to the antenna electrode, said oscillation means generating a high frequency low voltage oscillation signal in order to generate a weak electric field around the antenna electrode;
a current detection means for detecting a current which passes between the oscillation means and the antenna electrode depending on disturbance in the electric field between the antenna electrode and the passenger; and
a judgment means for judging a distance between the passenger and the portion of the vehicle based on the current detected by the current detection means. - View Dependent Claims (2, 3)
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4. A passenger detection system comprising:
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an antenna electrode which is provided to a portion of a vehicle located in front of a seat of a vehicle so as to face a passenger seated on the seat;
an oscillation means electrically connected to the antenna electrode, said oscillation means generating a high frequency low voltage oscillation signal in order to generate a weak electric field around the antenna electrode;
a current detection means for detecting a current which passes between the oscillation means and the antenna electrode depending on a strength of the electric field which is generated around the antenna electrode;
a judgment means for judging a distance between the passenger and the portion of the vehicle based on the current detected by the current detection means; and
an amplitude control means for controlling a voltage amplitude of the oscillation signal which is supplied by the oscillation means to the antenna electrode to a substantially constant value.
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5. A passenger detection system comprising:
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an antenna electrode which is provided to a portion of a vehicle located in front of a seat of the vehicle so as to face a passenger seated on the seat;
an oscillation means electrically connected to the antenna electrode, said oscillation means generating a high frequency low voltage oscillation signal in order to generate a weak electric field around the antenna electrode;
a current detection means for detecting a current which passes between the oscillation means and the antenna electrode depending on a strength of the weak electric field which is generated around the antenna electrode;
a phase difference detection means for detecting a phase difference between the oscillation signal supplied from the oscillation means and an output signal which is supplied to the antenna electrode by the generated weak electric field; and
a judgment means for judging a presence or absence of a passenger seated on the seat based on the phase difference detected by the phase difference detection means and producing a passenger presence indicating signal and judging a distance between the passenger and the portion of the vehicle based on the current detected by the current detection means. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A passenger detection method comprising the steps of:
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a field generation step in which a weak electric field is generated by supplying an oscillating signal to an antenna electrode which is provided to a portion of a vehicle located in front of a seat of the vehicle so as to face a passenger seated on the seat;
detecting a current output by the antenna electrode depending on a strength of the weak electric field;
detecting a phase difference between the oscillation signal an output signal which is supplied to the antenna electrode; and
a judgment step in which a presence or absence of a passenger seated on the seat is judged based on the phase difference which has been detected in the phase difference detecting step and the distance between the passenger and the portion of the vehicle is judged based on the current which has been detected in the current detecting step. - View Dependent Claims (18, 19, 20, 21, 22, 23)
a data communication step in which distance data obtained in the judgment step is sent to an air bag unit; and
an air bag unit setting step in which the air bag unit is set at a deployment mode in which the air bag unit deploys the air bag upon collision according to the distance data.
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19. A passenger detection method as claimed in claim 18, wherein in the judgment step, the presence or absence of a passenger seated on the seat is judged by comparing a phase difference detected in the phase difference detecting step with a prestored threshold value concerning the phase difference and whether the distance between the passenger and the portion of the vehicle is more than a minimum allowable distance or less than the minimum allowable distance is judged by comparing the current detected in the current detecting step with another threshold value concerning a current corresponding to the minimum allowable distance, and in the air bag unit setting step, the air bag unit is set at the no deployment mode if it is judged that no passenger is seated on the seat or the distance is less than the minimum allowable distance.
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20. A passenger detection method as claimed in claim 19, wherein the antenna electrode is provided to a dashboard of a car.
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21. A passenger detection method as claimed in claim 17, wherein in the phase difference detecting step, the phase difference between the oscillation signal and the output signal of the antenna electrode is detected by detecting a phase difference between a rising/falling edge of a square wave signal corresponding to the oscillation signal and a rising/falling edge of a square wave signal corresponding to the output signal.
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22. A passenger detection method as claimed in claim 17, wherein the oscillation signal comprises a high frequency low voltage square wave oscillation signal.
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23. A passenger detection method as claimed in claim 22, wherein an MPU (MicroProcessor Unit) generates the high frequency low voltage square wave oscillation signal.
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24. A passenger detection system comprising:
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an antenna electrode which is provided to a portion of a vehicle located in front of a seat of a vehicle so as to face a passenger seated on the seat;
an oscillation means electrically connected to the antenna electrode, said oscillation means generating a high frequency low voltage oscillation signal in order to generate a weak electric field around the antenna electrode;
a phase difference detection means for detecting a phase difference between the oscillation signal supplied from the oscillation means and an output signal which is supplied to the antenna electrode by the generated weak electric field; and
a judgment means for judging a presence or absence of a passenger seated on the seat based on the phase difference detected by the phase difference detection means.
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25. A passenger detection method comprising steps of:
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a field generation step in which a weak electric field is generated by supplying an oscillating signal to an antenna electrode which is provided to a portion of vehicle located in front of a seat of the vehicle so as to face a passenger seated on the seat;
detecting a phase difference between the oscillation signal and output signal which is supplied to the antenna electrode; and
a judgment step in which a presence or an absence of a passenger seated on a seat is judged based on the phase difference which has been detected in the phase difference detecting step.
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Specification