Capacitive occupant detection system

• US 8,957,689 B2
• Filed: 09/16/2011
• Issued: 02/17/2015
• Est. Priority Date: 09/23/2010
• Status: Expired due to Fees

• Current Assignee: IEE International Electronics & Engineering SA (Aerospace Hi-Tech Holding Group Company Limited)
• Original Assignee: IEE International Electronics & Engineering SA (Aerospace Hi-Tech Holding Group Company Limited)
• Inventors: Virnich, Michael, Hoyer, David, Thinnes, Martin
• Primary Examiner(s): NGUYEN, HOAI AN D
• Application Number:
  US13/823,394
• Publication Number:
  US 20130207676A1
• Time in Patent Office: 1,250 Days
• Field of Search: 324/684, 324/658, 324/649, 324/600, 324/688, 324/686, 324/679, 324/672, 324/671, 324/669, 324/664, 324/663, 324/662, 324/661, 324/660, 340/667, 340/666, 340/665
• US Class Current: 324/684
• 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
• CPC Class Codes: B60R 21/015 including means for detecting the presence or position of passengers, passenger seats or child seats , and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 21/0154 in combination with seat heating
• CPC Class Codes: G01N 27/22 by investigating capacitance
• CPC Class Codes: G01N 27/226 Construction of measuring vessels; Electrodes therefor
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G01V 3/088 operating with electric fields G01V3/082 takes precedence

Abstract

A capacitive occupant detection system comprises at least one antenna electrode to be arranged in a seat and an evaluation unit operatively coupled to said at least one antenna electrode, said evaluation unit being configured for applying, during operation, an alternating voltage signal to said antenna electrode and for detecting an amplitude and/or phase of a displacement current flowing from said antenna electrode towards ground. According to the invention said antenna electrode comprises an antenna electrode conductor and at least one dedicated ground electrode, said ground electrode being arranged at a predetermined distance of said antenna electrode conductor and extending along said antenna electrode conductor.

Claims

1. A capacitive occupant detection system comprising at least one antenna electrode to be arranged in a seat and an evaluation unit operatively coupled to said at least one antenna electrode, wherein said evaluation unit is configured for applying, during operation, an alternating voltage signal to said at least one antenna electrode and for detecting at least one of an amplitude or a phase of a displacement current flowing from said at least one antenna electrode towards ground,

and wherein said antenna electrode comprises an antenna electrode conductor and at least one dedicated ground electrode, said ground electrode being arranged at a predetermined distance of said antenna electrode conductor and extending along said antenna electrode conductor.

2. The capacitive occupant detection system as claimed in claim 1, wherein said evaluation unit further comprises circuitry for compensating a capacitive current flowing from said antenna electrode conductor to said at least one dedicated ground electrode.

3. The capacitive occupant detection system as claimed in claim 1, wherein said antenna electrode conductor comprises at least one of a conductive wire or a conductive trace applied on a carrier material.

4. An assembly of a seat heater and a capacitive occupant detection system according to claim 1, wherein said seat heater comprises at least one heater conductor to be arranged in a seat and wherein said seat heater and said capacitive occupant detection system are arranged in said seat in such a way, that said dedicated ground electrode is arranged between said heater conductor and said antenna electrode conductor.

5. The assembly of a seat heater and a capacitive occupant detection system as claimed in claim 4, wherein said heater conductor comprises at least one of a conductive wire or a conductive trace applied on a carrier material.

6. The assembly of a seat heater and a capacitive occupant detection system as claimed in claim 4, wherein said heater conductor and at least one of said antenna electrode conductor or said dedicated ground electrode are arranged on a common carrier material.

7. The assembly of a seat heater and a capacitive occupant detection system as claimed in claim 4, wherein said evaluation unit further comprises circuitry for compensating a capacitive current flowing from said antenna electrode conductor to said at least one dedicated ground electrode.

8. The assembly of a seat heater and a capacitive occupant detection system as claimed in claim 4, wherein said antenna electrode conductor comprises at least one of a conductive wire or a conductive trace applied on a carrier material.

9. The assembly of a seat heater and a capacitive occupant detection system as claimed in claim 7, wherein said antenna electrode conductor comprises at least one of a conductive wire or a conductive trace applied on a carrier material.

10. The capacitive occupant detection system as claimed in claim 2, wherein said antenna electrode conductor comprises at least one of a conductive wire or a conductive trace applied on a carrier material.