Capacitive proximity switch, and domestic appliance comprising the same

• US 7,782,069 B2
• Filed: 08/17/2006
• Issued: 08/24/2010
• Est. Priority Date: 08/30/2005
• Status: Active Grant

• Current Assignee: BSH Hausgeraete GmbH (Robert Bosch GmbH)
• Original Assignee: BSH Bosch und Siemens Hausgerã¤Te GmbH (Robert Bosch GmbH)
• Inventors: Klopfer, Wilfried
• Primary Examiner(s): Nguyen; Vincent Q
• Application Number:
  US12/065,306
• Publication Number:
  US 20080224758A1
• Time in Patent Office: 1,468 Days
• Field of Search: 324/686, 324/690, 327/517
• US Class Current: 324/686
• CPC Class Codes: D06F 34/32 characterised by graphical features, e.g. touchscreens
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes
• CPC Class Codes: H03K 2217/96076 with spring electrode

Abstract

A capacitive proximity switch includes an electrically conductive sensor area, which is covered by an electrically-insulating cover plate, as part of a capacitor having a capacitance which varies as a result of proximity. An associated evaluation circuit is provided, and an electrically-conducting body, via which the sensor area is connected to the evaluation circuit and which is arranged between the electrically-insulating cover plate and a mount disposed at a distance therefrom. A domestic appliance includes such a proximity switch. At least one electronic component of the evaluation circuit is arranged on the mount such that it protrudes into a cavity, which is surrounded by the electrically conductive body.

Claims

1. A capacitive proximity switch, comprising:

an electrically conducting sensor area and an electrically insulating cover plate covering said sensor area and forming part of a capacitor with a capacitance that changes upon being approached;

a support disposed at a spacing distance from said electrically insulating cover plate;

an evaluation circuit;

an electrically conductive body connecting said sensor area with said evaluation circuit and being disposed between said electrically insulating cover plate and said support; and

at least one electronic component of said evaluation circuit disposed on said support and protruding into a cavity surrounded by said electrically conductive body.

2. The proximity switch according to claim 1, wherein said at least one component is an active component of said evaluation circuit.

3. The proximity switch according to claim 2, wherein said active component is a switching element.

4. The proximity switch according to claim 1, wherein said electrically conductive body has a lower end facing away from said cover plate, and wherein said lower end rests against an electrically conductive contact of said support and is connected to said evaluation circuit via said electrically conductive contact.

5. The proximity switch according to claim 1, wherein said electrically conductive body has an upper end facing said cover plate and bracing against a lower face of said cover plate, and wherein at least a part of a surface of said conductive body forms at least part of said sensor area.

6. The proximity switch according to claim 1, which comprises a shielding surface disposed on a rear face of said support opposite said electrically conductive body, said shielding surface being disposed at least in a region opposite said electrically conductive body.

7. The proximity switch according to claim 1, wherein said electrically conductive body is a compression spring coiled from an elongated body.

8. The proximity switch according to claim 7, wherein said compression spring is substantially cylindrical in shape at an end thereof facing said support, at least in a cylindrical sub-region thereof.

9. The proximity switch according to claim 8, wherein said compression spring includes a conical sub-region adjoining said cylindrical sub-region at an end thereof facing away from said support.

10. The proximity switch according to claim 1, wherein said electrically conductive body is an inherently elastic hollow body.

11. An input panel for a domestic appliance, comprising at least one proximity switch according to claim 1.

12. A domestic appliance, comprising an input panel with at least one proximity switch according to claim 1.