Passenger seat device having occupant detector embedded in seat of automotive vehicle

• US 20080017625A1
• Filed: 07/09/2007
• Published: 01/24/2008
• Est. Priority Date: 07/19/2006
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Ito, Hiroyuki, Yamanaka, Shoichi, Kamizono, Tsutomu
• Granted Patent: US 8,669,492 B2
• Time in Patent Office: Days
• US Class Current: 219/202
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/0033 mounted on or in the foam cushion
• CPC Class Codes: B60N 2/0035 characterised by the sensor data transmission, e.g. wired connections or wireless transmitters therefor; characterised by the sensor data processing, e.g. seat sensor signal amplification or electric circuits for providing seat sensor information
• CPC Class Codes: B60N 2/5685 Resistance
• CPC Class Codes: B60N 2210/12 Capacitive; Electric field

Abstract

A passenger seat device includes a seat heater embedded in a seat and a detector electrode embedded underneath the seat heater. Electric power is supplied to the seat heater from an on-board battery through seat heater switches. Alternating voltage or current is supplied to the detector electrode. The detector electrode potential relative to the ground is lowered when the seat is occupied by a passenger. The changes in the potential of the detector electrode is detected by an occupant detector including a microcomputer. The detection is performed when the seat heater is brought to a floating state to suppress an amount of capacitance formed between the seat heater and the detector electrode. Thus, a sensitivity of the occupant detector is improved. The detector electrode may be eliminated, and the occupant conditions may be detected based on a potential of the seat heater to which alternating current or voltage is supplied.

Claims

1. A passenger seat device for an automotive vehicle, comprising:

a seat heater embedded at least in a seat in parallel to a seat surface, electric current being supplied to the seat heater in a controlled manner from an on-board power source;

a detector electrode embedded in the seat;

an alternating current power source for supplying an alternating voltage having a predetermined frequency to the detector electrode;

a detector for detecting occupancy conditions of the seat based on changes in an electric potential of the detector electrode, wherein;

both ends of the seat heater are disconnected from the on-board power source at a predetermined interval by opening seat heater switches, thereby bringing the seat heater to a floating state; and

the detector detects the occupancy conditions of the seat during a period in which the seat heater is in the floating state.

2. The passenger seat device as in claim 1, wherein the seat heater switches are also used as switches for supplying power of the on-board power source to the seat heater in a controlled manner.

3. The passenger seat device as in claim 1, wherein the seat heater is embedded in the seat at a position closer to a seat surface than the detector electrode.

4. The passenger seat device as in claim 1, further including an insulating film disposed between the seat heater and the detector electrode.

5. A passenger seat device for an automotive vehicle, comprising:

a seat heater embedded in a seat in parallel to a seat surface, electric current being supplied to the seat heater in a controlled manner from an on-board power source;

an alternating current power source for supplying an alternating voltage having a predetermined frequency to the seat heater;

an occupant detector for detecting occupancy conditions of the seat based on changes in an electric potential of the seat heater relative to a ground potential, wherein;

the detector detects the occupancy conditions of the seat when the seat heater is brought to a floating potential by opening heater switches for supplying heating power to the seat heater from the on-board power source.

6. The passenger seat device as in claim 5, wherein the seat heater is connected to the alternating current power source and the occupant detector through a coupling capacitor.

7. The passenger seat device as in claim 5, wherein the seat heater is connected to the alternating current power source and the occupant detector through a diode.

8. The passenger seat device as in claim 5, wherein the seat heater is connected to the alternating current power source and the occupant detector through a switch that closes when the heater switches are opened.

9. The passenger seat device as in claim 5, wherein the alternating current power source is connected to an low potential end of the seat heater through a load element, and the occupant detector is directly connected to the low potential end of the seat heater.