Hybrid occupant detection system
First Claim
1. An occupant detection system, comprising:
- a detection electrode provided in at least one of a seat bottom and a seatback of a seat;
a phase difference measuring unit that supplies a reference signal comprising a sinusoidal wave to the detection electrode via a resistive element, detects the potential of the detection electrode as an electrode signal, and measures a phase lag time of the electrode signal relative to the reference signal;
a direct current measuring unit that applies a steady DC voltage to the detection electrode via a resistive element, detects the potential of the detection electrode, and measures time it takes from start of application of the DC voltage to the detection electrode to the time when the detection electrode reaches a given potential, as a charge time; and
a detecting unit that detects an occupant based on the phase lag time and the charge time, using the phase difference measuring unit and the direct current measuring unit.
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Accused Products
Abstract
An occupant detection system includes a detection electrode provided in a vehicle seat, a phase difference measuring unit, a direct current measuring unit, and a detecting unit that detects an occupant. The phase difference measuring unit supplies a reference signal comprising a sinusoidal wave to the detection electrode via a resistive element, detects the potential of the detection electrode as an electrode signal, and measures a phase lag time of the electrode signal relative to the reference signal. The direct current measuring unit applies a steady DC voltage to the detection electrode via a resistive element, detects the potential of the detection electrode, and measures time it takes from start of application of the DC voltage to the time when the detection electrode reaches a given potential, as a charge time. The detecting unit detects an occupant based on the phase lag time and the charge time.
7 Citations
10 Claims
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1. An occupant detection system, comprising:
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a detection electrode provided in at least one of a seat bottom and a seatback of a seat; a phase difference measuring unit that supplies a reference signal comprising a sinusoidal wave to the detection electrode via a resistive element, detects the potential of the detection electrode as an electrode signal, and measures a phase lag time of the electrode signal relative to the reference signal; a direct current measuring unit that applies a steady DC voltage to the detection electrode via a resistive element, detects the potential of the detection electrode, and measures time it takes from start of application of the DC voltage to the detection electrode to the time when the detection electrode reaches a given potential, as a charge time; and a detecting unit that detects an occupant based on the phase lag time and the charge time, using the phase difference measuring unit and the direct current measuring unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification