Pressure sensor

• US 20010020714A1
• Filed: 03/09/2001
• Published: 09/13/2001
• Est. Priority Date: 03/10/2000
• Status: Active Grant

• Current Assignee: Wet Automotive Systems AG (Gentherm Incorporated)
• Original Assignee: Wet Automotive Systems AG (Gentherm Incorporated)
• Inventors: Kraetzl, Jurgen, Hugenschmidt, Markus
• Granted Patent: US 6,591,685 B2
• Time in Patent Office: Days
• US Class Current: 257/309
• 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 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 7/06 by electrostatic action
• CPC Class Codes: G01L 1/142 using capacitors

Abstract

The present invention relates to a pressure sensor comprising a capacitor with a first capacitor pole element (1) and at least one additional capacitor pole element (3) arranged at a distance from one another. In accordance with the invention, at least one capacitor pole element (1, 3) has at least one textured region (31, 31′ and/or 32, 32′) on the surface of its conductive components facing toward the other capacitor pole element (3, 1), and the distance between the two capacitor pole elements (1,3) is different in the textured region (31,31′ and/or 32; 32′) than in an adjacent region (32, 32′ and/or 31, 31′) to the textured region (31; 31′ and/or 32,32′). The difference between these two different distances can be changed—more particularly, reduced—by deformation of at least one capacitor pole element (1,3) when the capacitor is subjected to pressure.

Claims

1. A pressure sensor comprising a capacitor having a first capacitor pole element and a second capacitor pole element, which are arranged at a distance from one another, wherein at least one of said first and second capacitor pole elements has at least one textured region on the surface of its conductive components facing toward the other capacitor pole element, and wherein the distance between the first and second capacitor pole elements is different in the textured region than in a region adjacent to the textured region, and wherein the difference between the distance between the first and second capacitor pole elements in the textured region and the region adjacent to the textured region is adapted to change by deformation of at least one of said first and second capacitor pole elements when the capacitor is subjected to pressure.

8. A pressure sensor according to

claim 1

wherein at least one capacitor pole element is at least partly rigid.

11. A pressure sensor according to

claim 1

wherein at least one of the capacitor pole elements has a metallized textile made of synthetic fibers.

14. A pressure sensor according to

claim 1

wherein at least one of the capacitor pole elements has electrically conductive fibers, which are embedded in an electrically nonconductive, elastically deformable material.

17. A pressure sensor according to

claim 1

wherein at least two different, electrically nonconductive media are arranged between the two capacitor pole elements, and wherein at least one of the media is a fluid which can be displaced from the region between the two capacitor pole elements when pressure is applied to the pressure sensor.

2. A pressure sensor comprising a first capacitor pole element, a second capacitor pole element, and an electrically nonconductive insulating device, of which at least part is arranged between the two first and second capacitor pole elements, wherein at least one capacitor pole element in at least one section of its surface facing the other capacitor pole element is spaced apart from the insulating device, and wherein the section is adapted to be moved toward the insulating device through flexible deformation of the respective capacitor pole element by subjecting the pressure sensor to pressure.

4. A pressure sensor according to

claim 2

wherein at least one of the capacitor pole elements is compressible toward the insulating device.

6. A pressure sensor according to

claim 2

wherein at least one capacitor pole element is compressible only in one surface region facing the insulating device.

9. A pressure sensor according to

claim 2

wherein at least one capacitor pole element is at least partly rigid.

12. A pressure sensor according to

claim 2

wherein at least one of the capacitor pole elements has a metallized textile made of synthetic fibers.

15. A pressure sensor according to

claim 2

wherein at least one of the capacitor pole elements has electrically conductive fibers, which are embedded in an electrically nonconductive, elastically deformable material.

18. A pressure sensor according to

claim 2

wherein the insulating device is at least partly rigid and is essentially incompressible in the direction of the applied pressure.

20. A pressure sensor according to

claim 2

wherein the insulating device is embodied as a foil or film.

3. A pressure sensor comprising a first capacitor pole element, a second capacitor pole element, and an electrically nonconductive insulating device, of which at least part is arranged between the two first and second capacitor pole elements, wherein at least one capacitor pole element has on a surface of its electrically conductive components facing toward the other capacitor pole element, at least one textured region having an associated normal height (H), and wherein the normal height (H) is adapted to be reduced to a detection height (h) through flexible deformation of the respective capacitor pole element when the pressure sensor is subjected to pressure.

5. A pressure sensor according to

claim 3

wherein at least one of the capacitor pole elements is compressible toward the insulating device.

7. A pressure sensor according to

claim 3

wherein at least one capacitor pole element is compressible only in one surface region facing the insulating device.

10. A pressure sensor according to

claim 3

wherein at least one capacitor pole element is at least partly rigid.

13. A pressure sensor according to

claim 3

wherein at least one of the capacitor pole elements has a metallized textile made of synthetic fibers.

16. A pressure sensor according to

claim 3

wherein at least one of the capacitor pole elements has electrically conductive fibers, which are embedded in an electrically nonconductive, elastically deformable material.

19. A pressure sensor according to

claim 3

wherein the insulating device is at least partly rigid and is essentially incompressible in the direction of the applied pressure.

21. A pressure sensor according to

claim 3

wherein the insulating device is embodied as a foil or film.

22. A pressure sensor according to

claim 3

wherein the normal height (H) of the textured region between the insulating device and the respective capacitor pole element, at least in one section, is between ten microns and ten millimeters.

23. A pressure sensor according to

claim 22

wherein one of the capacitor pole elements comprises a base of a vehicle seat.