CONTROL UNIT FOR DOMESTIC APPLIANCES

• US 20090115645A1
• Filed: 11/11/2008
• Published: 05/07/2009
• Est. Priority Date: 05/12/2006
• Status: Active Grant

• Current Assignee: EGO Elektro-Gerã¤Tebau GmbH (EGO Blanc und Fischer & Company GmbH)
• Original Assignee: EGO Elektro-Gerã¤Tebau GmbH (EGO Blanc und Fischer & Company GmbH)
• Inventors: Roth, Bernhard
• Granted Patent: US 8,462,022 B2
• Time in Patent Office: Days
• US Class Current: 341/33
• 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 2217/960755 Constructional details of capacitive touch and proximity switches
• CPC Class Codes: H03K 2217/96079 using a single or more light guides

Abstract

A control unit comprising a light guide is formed and positioned in a circuit board for providing visual indication to a user of an appliance, such as a cooktop. The light guide receives light from a source, typically in the form of an LED on the circuit board, typically positioned laterally to the light guide, and the light guide receives and directs the light to the user. In some embodiments, the light guide is positioned behind a cover, which may have indicia thereon for providing operating information to the user. Portions of the light guide may be coated with an electrically conductive coating so as to also form a portion of a capacitance touch switch for detecting user input for controlling operation of the appliance.

Claims

1. A control unit for a domestic appliance comprising a cooktop, said control unit for installation behind a cover of the domestic appliance, said control unit comprising:

at least one sensor element (14) for generating an actuation-dependent sensor signal;

at least one luminous source (12) associated with the sensor element (14);

at least one light guide (13) associated with the luminous source (12) for changing the direction of the light emitted by the light guide (13) with respect to the light entered by the light guide (13); and

a circuit board (11), on which the luminous source (12), the light guide (13) and the sensor element (14, 15) are arranged, wherein

the luminous source (12) is arranged on a side of the circuit board (11) which is faces away from the cover (10),

the light guide (13) is arranged at least in part in an aperture opening of the circuit board (11) and

the light guide (13) has a conductive, substantially flat surface (14) on a side facing the cover (10), with the sensor element formed at least in part by the conductive surface (14).

2. The control unit of claim 1, wherein the sensor element is a capacitive sensor element (14) generating an actuation-dependent capacitance.

3. The control unit of claim 1, wherein the conductive surface is formed by coating the light guide on the side facing the cover (10) with a conductive coating (14) that is transparent at least at certain parts.

4. The control unit of claim 1 wherein the light guide (13) is electrically conductive.

5. The control unit of claim 1 wherein the directional change of the light entering the light guide (13) with respect to the light emitted by the light guide (13) is 90 degrees.

6. The control unit of claim 5 wherein the luminous source is an LED (12).

7. The control unit of claim 1 wherein an area (15) of the circuit board (11) adjacent to the light guide (13) comprises an electrically conductive coating.

8. The control unit of claim 1 wherein an area on the light guide adjacent to the circuit board (11) comprises an electrically conductive coating.

9. The control unit of claim 1 wherein a conductive contact surface (15) is provided around the aperture opening on the circuit board on the side facing the cover and makes electrical contact with the conductive surface (14) of the light guide (13), wherein the sensor element is formed by the conductive surface (14) of the light guide (13) and the contact surface (15).