Film-type electrostatic capacitance sensor for detecting seat occupancy

• US 7,859,423 B2
• Filed: 01/24/2008
• Issued: 12/28/2010
• Est. Priority Date: 01/25/2007
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamanaka, Shoichi, Kamizono, Tsutomu
• Primary Examiner(s): Zimmerman; Brian A
• Assistant Examiner(s): Nguyen; An T
• Application Number:
  US12/011,187
• Publication Number:
  US 20080180234A1
• Time in Patent Office: 1,069 Days
• Field of Search: 340/500, 340/540, 340/665, 340/666, 340/667, 340/425.5, 340/438, 180271-273, 297/217.1, 297/217.3
• US Class Current: 340/667
• 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 2/5685 Resistance
• CPC Class Codes: B60N 2210/12 Capacitive; Electric field

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 of the seat face portion and the back rest portion of the seat, the planar mat having a resin film extending along the one of the seat face portion and the back rest portion of the seat, 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 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 both sides of the resin film;

the electrode protecting portion provided on one of the sides of the resin film includes a resin coating layer;

the electrode protecting portion provided on the other of the sides of the resin film includes a preformed resin film as a cover film;

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

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

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

the resin coating layer is disposed closer to the heater portion; and

the resin coating layer is formed on the same surface of the resin film as the detector circuit portion mounted on the resin film.

2. 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.

3. 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;

the electrode protecting portion provided on the other of the sides of the resin film includes a preformed resin film as a cover film so as to improve electrical insulation and waterproofness;

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

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

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

the flexible resin coating layer is disposed closer to the heater portion; and

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.

4. The film-type electrostatic capacitance sensor according to claim 3, wherein the flexible resin coating layer includes a resin having a fire retardant characteristic that is higher than the resin film.