Operating control comprising a capacitive sensor element and an electrical device comprising an operating control of this type

• US 7,667,947 B2
• Filed: 07/11/2006
• Issued: 02/23/2010
• 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
• Primary Examiner(s): Thomas; Eric
• Assistant Examiner(s): Sinclair; David M
• Application Number:
  US11/456,749
• Publication Number:
  US 20060243462A1
• Time in Patent Office: 1,323 Days
• Field of Search: 361/277, 361/279, 361/288, 361/287, 361/290, 361/291
• US Class Current: 361/290
• 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 formed by a flat material forming a cover being larger than said operating field and extending beyond said operating field and said cover is of a thinner thickness in the vicinity of said operating field, and wherein the application of the pressure onto said outside of said operating 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 of 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 10, 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 spacing 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 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.

18. The operating device of claim 17 wherein the outer surface of the operating field bears indicia providing operating instructions to the user.

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

20. The operating device of claim 19 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.

21. An operating device for an electrical appliance having an operating field capable of varying shape,

having a plurality of capacitive sensor elements below said operating field, wherein operation of said operating device is configured to occur by contacting and applying pressure on said operating field, wherein each of said sensor elements has a respective electrically conductive, lower sensor surface as a capacitor plate, wherein said operating field is above said respective lower sensor surface and a dielectric layer is located between said operating field and said respective sensor surface, wherein said operating field is a single electrically conductive metallic layer,

wherein the electrically conductive metallic layer comprises a metal foil having a thickness between 100 micrometers and 1 millimeter, without any openings therein positioned over any of the plurality of capacitor sensor elements and comprising a flat material forming a cover being larger than said operating field and extending beyond said operating field, and

wherein said operating device is configured such that the application of the pressure onto said operating field by a user'"'"'s finger causes the operating field to approach but not contact one of said lower sensor surfaces thereby effecting a change in capacitance at the respective capacitive sensor element.

22. An operating device for an electrical appliance having an operating field capable of varying shape,

having a plurality of capacitive sensor elements below said operating field, wherein operation occurs by contacting and applying pressure on said operating field by a user'"'"'s finger, wherein each of said sensor elements has a respective electrically conductive, lower sensor surface as a capacitor plate, wherein said operating field is above said respective lower sensor surface and a dielectric layer is located between said operating field and said respective sensor surface,

wherein the electrically conductive metallic layer comprises a metal foil having a thickness greater than 100 micrometers without any openings therein positioned over any of the plurality of capacitor sensor elements and comprising a flat material forming a cover being larger than said operating field and extending beyond said operating field, and

wherein said operating device is configured such that the application of the pressure onto said operating field causes the operating field to approach but not contact one of said lower sensor surfaces thereby effecting a change in capacitance at the respective capacitive sensor element.