Film-type electrostatic capacitance sensor for detecting seat occupancy

• US 20080180234A1
• Filed: 01/24/2008
• Published: 07/31/2008
• Est. Priority Date: 01/25/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamanaka, Shoichi, Kamizono, Tsutomu
• Granted Patent: US 7,859,423 B2
• Time in Patent Office: Days
• US Class Current: 340/438
• 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 2/5685 Resistance

Abstract

A film-type electrostatic capacitance sensor is provided for detecting seat occupancy and for reducing discomfort to a seat occupant and which is easy to produce. The mat of the film-type electrostatic capacitance sensor can be located in a seat portion of a vehicle seat and can include electrodes formed on both sides of a resin film and of a resin coating layer covering the electrodes. The coating layer can be a flexible resin to decrease discomfort for an occupant.

Claims

1. A film-type electrostatic capacitance sensor for detecting occupancy of a seat mounted in a vehicle, the sensor comprising:

a planar mat buried in one of a seat face portion and a back rest portion of the seat, the planar mat extending along the one, the planar mat having a resin film extending along the one, and at least two electrodes provided individually on different sides of the resin film, the planar mat including an electrically insulating electrode protecting portion covering at least an exposed portion of each of the at least two electrodes; and

a detector circuit portion for detecting a change in an electrical state of the planar mat between the at least two electrodes based on whether the seat is occupied, wherein;

the two electrodes are provided individually on substantially both sides of the resin film; and

the electrode protecting portion provided on at least one of the sides of the resin film includes a resin coating layer.

2. The film-type electrostatic capacitance sensor according to claim 1, wherein the electrode protecting portion is provided individually as covering portions on both of the sides of the resin film to cover the exposed portion of the at least two electrodes, the respective covering portions each composed of the resin coating layer.

3. The film-type electrostatic capacitance sensor according to claim 1, wherein the electrode protecting portion includes a cover film including a pre-formed resin film to cover the at least an exposed portion.

4. The film-type electrostatic capacitance sensor according to claim 3, wherein:

the planar mat is interposed between a cushion pad of the seat and a surface portion of the seat; and

the resin coating layer is disposed closer to the cushion pad.

5. The film-type electrostatic capacitance sensor according to claim 3, wherein:

the planar mat is interposed between a heater portion of the seat and a surface portion of the seat; and

the resin coating layer is disposed closer to the heater portion.

6. The film-type electrostatic capacitance sensor according to claim 3, wherein the resin coating layer is formed on the same surface of the resin film as the detector circuit portion mounted on the resin film.

7. The film-type electrostatic capacitance sensor according to claim 1, wherein the coating layer includes a resin having a higher fire retardant characteristic than the resin film.

13. The film-type electrostatic capacitance sensor according to claim 3, wherein:

the planar mat is interposed between a heater portion of the seat and a surface portion of the seat; and

the flexible resin coating layer is disposed closer to the heater portion.

8. A film-type electrostatic capacitance sensor for detecting occupancy of a seat mounted in a vehicle, the sensor comprising:

a planar mat buried in one of a seat face portion and a back rest portion of the seat, the planar mat extending along the one, the planar mat having two resin films in stacked relation and extending along the one, the planar mat including at least two electrodes provided individually on different sides of the two resin films, and an electrically insulating electrode protecting portion covering at least an exposed portion of each of the at least two electrodes; and

a detector circuit portion for detecting a change in an electrical state of the planar mat between the at least two electrodes based on whether the seat is occupied, wherein;

the at least two electrodes are provided individually on respective surfaces of the two resin films provided in stacked relation,

one of the two electrodes is disposed between the two resin films, and

the electrode protecting portion covering the other of the two electrodes can include a resin coating layer.

9. The film-type electrostatic capacitance sensor according to claim 8, wherein the coating layer includes a resin having a higher fire retardant characteristic than the resin film.

10. A film-type electrostatic capacitance sensor capable of detecting seat occupancy by an occupant of a seat mounted in a vehicle, the sensor reducing a discomfort of the occupant, the sensor comprising:

a planar mat buried in a portion of the seat capable of being in contact with the occupant, the planar mat extending along a plane associated with the portion, the planar mat including a resin film and two electrodes provided on different sides of the resin film, and an electrically insulating electrode protecting portion covering at least an exposed portion of each of the two electrodes; and

a detector circuit portion for detecting an electrical change between the two electrodes based on whether the seat is occupied,

wherein the electrode protecting portion provided on at least one of the sides of the resin film includes a flexible resin coating layer having a flexibility so as to reduce the discomfort of the occupant.

11. The film-type electrostatic capacitance sensor according to claim 10, wherein the flexible resin coating layer is covered by a cover film that includes a pre-formed resin film to cover the two electrodes.

12. The film-type electrostatic capacitance sensor according to claim 10, wherein:

the planar mat is interposed between a cushion pad of the seat and a surface portion of the seat; and

the flexible resin coating layer is disposed closer to the cushion pad than the resin film and the two electrodes.

14. The film-type electrostatic capacitance sensor according to claim 10, wherein the flexible resin coating layer is formed on the same surface of the resin film as the detector circuit portion mounted on the resin film.

15. The film-type electrostatic capacitance sensor according to claim 10, wherein the resin film includes two resin films in stacked relation, the two electrodes provided separately on respective surfaces of the two resin films,

one of the two electrodes is disposed between the two resin films, and

the electrode protecting portion covering the other of the two electrodes includes the flexible resin coating layer.

16. The film-type electrostatic capacitance sensor according to claim 10, wherein the flexible resin coating layer includes a resin having a fire retardant characteristic that is higher than the resin film.