OCCUPANT DETECTION APPARATUS, OCCUPANT DETECTION METHOD AND VEHICLE

• US 20120161777A1
• Filed: 12/19/2011
• Published: 06/28/2012
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Nakagawa, Hajime
• Granted Patent: US 9,205,762 B2
• Time in Patent Office: Days
• US Class Current: 324/457
• 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: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 21/0154 in combination with seat heating

Abstract

An occupant detection apparatus includes an electrostatic capacitance type sensor having a main electrode, a sub electrode and a guard electrode, an impedance measurement device that outputs an alternating current signal to measure an impedance, and an occupant discrimination device that discriminates an occupant.

The guard electrode is provided oppositely to main electrode and not oppositely to the sub electrode. The impedance measurement device outputs an alternating current signal to pass the signal through the main electrode so as to measure a main impedance. Further, the impedance measurement device outputs the alternating current signal to pass the signal through sub electrode so as to measure a sub impedance. The occupant discrimination device discriminates the occupant based on an electrostatic capacitance component of the main impedance and a resistance value component of the sub impedance.

Claims

1. An occupant detection apparatus comprising:

an electrostatic capacitance type sensor including

(i) a main electrode provided in a seating face portion of a seat,

(ii) a sub electrode provided away from the main electrode in a planar direction, and

(iii) a guard electrode provided between the seating face portion and a seat frame, wherein the guard electrode is provided between the main electrode and the seat frame, oppositely to the main electrode and not oppositely to the sub electrode;

an impedance measurement device that outputs an alternating current signal to the electrostatic capacitance type sensor so as to measure an impedance of the electrostatic capacitance type sensor,

the impedance measurement device outputting the alternating current signal to pass the alternating current signal through the main electrode so as to measure a main impedance,

the impedance measurement device outputting the alternating current signal to pass the alternating current signal through the sub electrode so as to measure a sub impedance; and

an occupant discrimination device that discriminates an occupant based on an electrostatic capacitance component of the main impedance and a resistance value component of the sub impedance measured by the impedance measurement device.

2. The occupant detection apparatus according to claim 1,

wherein the impedance measurement device passes the alternating current signal at least between the main electrode and the seat frame so as to measure the main impedance.

3. The occupant detection apparatus according to claim 1,

wherein the impedance measurement device passes the alternating current signal between the main electrode and the seat frame so as to measure the main impedance, and passes the alternating current signal between the sub electrode and the seat frame so as to measure the sub impedance.

4. The occupant detection apparatus according to claim 1,

wherein the impedance measurement device passes the alternating current signal between the main electrode and the seat frame so as to measure the main impedance, and passes the alternating current signal between the main electrode and the sub electrode so as to measure the sub impedance.

5. The occupant detection apparatus according to claim 1,

wherein the impedance measurement device passes the alternating current signal between at least the main electrode and the sub electrode so as to measure the sub impedance.

6. The occupant detection apparatus according to claim 1,

wherein the impedance measurement device passes the alternating current signal between the main electrode and the seat frame so as to measure the main impedance, and passes the alternating current signal between the main electrode and the sub electrode so as to measure the sub impedance.

7. The occupant detection apparatus according to claim 1,

wherein the impedance measurement device has a connection selection device that, upon passing the alternating current signal to measure the main impedance and the sub impedance, selects a connection between the main electrode and the seat frame, between the sub electrode and the seat frame, or between the main electrode and the sub electrode.

9. A vehicle having the occupant detection apparatus and the seat according to claim 1.

8. An occupant discrimination method for discriminating an occupant using an occupant detection apparatus including:

an electrostatic capacitance type sensor containing a main electrode provided in a seating face portion of a seat, a sub electrode provided away from the main electrode in a planar direction, and a guard electrode provided between the seating face portion and a seat frame, wherein the guard electrode is provided between the main electrode and the seat frame oppositely to the main electrode and not oppositely to the sub electrode; and

an impedance measurement device that outputs an alternating current signal to the electrostatic capacitance type sensor to measure an impedance of the electrostatic capacitance type sensor,

the method comprising;

an impedance measurement step of outputting the alternating current signal to pass the alternating current signal through the main electrode so as to measure a main impedance, and outputting the alternating current signal to pass the alternating current signal through the sub electrode so as to measure a sub impedance, by the impedance measurement device; and

an occupant discrimination step of discriminating an occupant based on an electrostatic capacitance component of the main impedance and a resistance value component of the sub impedance measured by the impedance measurement device.

10. An occupant detection apparatus comprising:

an electrostatic capacitance type sensor including

(i) a main electrode provided in a seating face portion of a seat,

(ii) a sub electrode provided away from the main electrode in a planar direction, and

(iii) a guard electrode provided between the seating face portion and a seat frame, wherein the guard electrode is provided between the main electrode and the seat frame, oppositely to the main electrode and not oppositely to the sub electrode;

an impedance measurement device that outputs an alternating current signal to the electrostatic capacitance type sensor so as to measure an impedance of the electrostatic capacitance type sensor,

the impedance measurement device outputting the alternating current signal to pass the alternating current signal through the main electrode so as to measure a main impedance,

the impedance measurement device outputting the alternating current signal to pass the alternating current signal through the sub electrode so as to measure a sub impedance; and

an occupant discrimination device that discriminates an occupant based on an electrostatic capacitance component of the main impedance and/or the sub impedance and a resistance value component of the main impedance and/or the sub impedance.

11. An occupant detection apparatus comprising:

an electrostatic capacitance type sensor including

(i) main electrode provided in a seating face portion of a seat,

(ii) a sub electrode provided away from the main electrode in a planar direction, and

(iii) a guard electrode provided between the seating face portion and a seat frame, wherein the guard electrode is provided between the main electrode and the seat frame, oppositely to the main electrode and not oppositely to the sub electrode;

an impedance measurement device that outputs an alternating current signal to the electrostatic capacitance type sensor so as to measure an impedance of the electrostatic capacitance type sensor,

the impedance measurement device outputting the alternating current signal to passes the alternating current signal between at least the main electrode and the sub electrode so as to measure the sub impedance; and

an occupant discrimination device that discriminates an occupant based on an electrostatic capacitance component of the sub impedance and a resistance value component of the sub impedance.

12. An occupant detection apparatus comprising:

an electrostatic capacitance type sensor including

(i) a main electrode provided in a seating face portion of a seat, and

(ii) a guard electrode provided between the seating face portion and a seat frame, wherein the guard electrode is provided between the main electrode and the seat frame, oppositely to the main electrode;

an impedance measurement device that outputs an alternating current signal to the electrostatic capacitance type sensor so as to measure an impedance of the electrostatic capacitance type sensor,

the impedance measurement device outputting the alternating current signal to pass the alternating current signal through the main electrode so as to measure a main impedance; and

an occupant discrimination device that discriminates an occupant based on an electrostatic capacitance component of the main impedance and a resistance value component of the main impedance.