OPERATING DEVICE WITH A CAPACITIVE SENSOR ELEMENT AND ELECTRICAL APPLIANCE WITH SUCH AN OPERATING DEVICE

• US 20060243462A1
• Filed: 07/11/2006
• Published: 11/02/2006
• Est. Priority Date: 01/12/2004
• Status: Active Grant

• Current Assignee: Diehl AKO Stiftung & Company KG
• Original Assignee: EGO Elektro-Gerã¤Tebau GmbH (EGO Blanc und Fischer & Company GmbH)
• Inventors: Dorwarth, Ralf, Schilling, Wilfried
• Granted Patent: US 7,667,947 B2
• Time in Patent Office: Days
• US Class Current: 172/10
• CPC Class Codes: G01D 5/2417 by varying separation
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/975 using a capacitive movable element
• CPC Class Codes: H05B 3/746 Protection, e.g. overheat cutoff, hot plate indicator

Abstract

An operating control device, such as for an appliance, is disclosed comprising sensor elements with a capacitive sensing function, the elements being located underneath a metallic surface that is used as the operating field. An insulating layer is situated between the elements and the metallic surface. When pressure is applied to the metallic surface the capacitance of the sensor element is altered by capacitive coupling. This alteration of capacitance can be determined by a corresponding evaluation circuit or the like for detecting activation of the device.

Claims

1. An operating device for an electrical appliance having an operating field capable of varying shape, having a capacitive sensor element below said operating field, wherein operation occurs by applying pressure on said operating field, said sensor element having an electrically conductive, lower sensor surface as a capacitor plate, wherein said operating field is above said lower sensor surface and a dielectric layer is located between said operating field and said sensor surface, wherein said operating field is electrically conductive at least on its outside and the application of the pressure onto said operation field causes the operating field to approach said lower sensor surface thereby effecting a change in capacitance at the capacitive sensor element.

2. The operating device according to claim 1, wherein said operating field is electrically conductive.

3. The operating device according to claim 1, wherein said operating field is a single metallic layer.

4. The operating device according to claim 1, wherein said operating field is an uninterrupted planar surface in the vicinity of said operating field.

5. The operating device according to claim 1, wherein said operating field is made from a metal sheet having a thickness of less than 1 millimeter.

6. The operating device according to claim 1, wherein said dielectric layer comprises air.

7. The operating device according to claim 6, wherein said dielectric layer is an air layer.

8. The operating device according to claim 1, wherein said dielectric layer is thinner than 1 millimeter.

9. The operating device according to claim 1, wherein said operating field is thinner than 1 millimeter.

10. The operating device according to claim 1, wherein one said operating field and a plurality of said sensor elements are provided, each said sensor element having one said sensor surface and said operating field above said sensor surface and a dielectric layer between each sensor surface and the operating field, wherein said sensor elements are juxtaposed on a planar surface.

11. The operating device according to claim 1, wherein at least one said sensor surface is surrounded by a conductive surface forming a grounding surface with a gap between the conductive surface and the at least one sensor surface.

12. The operating device according to claim 11, wherein said grounding surface is a metal coating.

13. The operating device according to claim 12, wherein each sensor element is placed on a support, wherein said grounding surface surrounds one of said sensor surface, wherein the grounding surface is formed from the same metal coating by structuring.

14. The operating device according to claim 12, wherein a spacing layer is applied to a layer forming said sensor surface and said grounding surface, wherein said spacing layer has at least one recess in a vicinity of said sensor surface, said operating field being located on said insulating flat material layer and said dielectric layer being formed in said at least one recess of said spacing layer through spacing between said sensor surface and said operating field.

15. The operating device according to claim 14, wherein said spacing layer is of flat insulating material.

16. The operating device according to claim 1, wherein an elastic, insulating flat material is placed between said sensor surface and said operating field and is compressed by applying pressure on said operating field.

17. The operating device according to claim 1, wherein said operating field is formed by a flat material forming a cover being significantly larger than said operating field and extending significantly beyond said operating field.

18. The operating device according to claim 17, wherein the cover is of a thinner thickness in the vicinity of said operating field.

19. The operating device according to claim 1 wherein the operating field has an outer surface facing a user, the operating field integrally formed as part of a panel or defined by a cutout in the frame of a household cooking appliance.

20. The operative device according to claim 1 wherein the operative device is incorporated into an electrical appliance.

21. The operating device of claim 1 wherein the electrical appliance is an electric cooktop with an all-round frame and wherein said operating device is integrated into said frame and an operating field is formed by said frame.

22. The operating device of claim 19 wherein the outer surface of the operating field bears indicia providing operating instructions to the user.