TOUCH SWITCH FOR ELECTRICAL APPLIANCES AND ELECTRICAL APPLIANCE PROVIDED WITH SUCH SWITCH

• US 20090090605A1
• Filed: 10/08/2008
• Published: 04/09/2009
• Est. Priority Date: 10/08/2007
• Status: Active Grant

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: BRAGHINI, GIORGIO, ARIONE, ETTORE, ARENA, GIUSEPPE, LAZZAROTTO, ROBERTO
• Granted Patent: US 7,705,257 B2
• Time in Patent Office: Days
• US Class Current: 200/314
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches
• CPC Class Codes: H03K 2217/96076 with spring electrode
• CPC Class Codes: H03K 2217/96079 using a single or more light guides

Abstract

A touch switch for an electrical appliance having a capacitive flat electrode, a light source, a transparent cover and a printed circuit board connected to the electrode is disclosed. The light source is mounted on a face of the printed circuit board opposite the transparent cover and the printed circuit board presents a cut-out for allowing light transmission from the light source towards the transparent cover.

Claims

1. A touch switch for an appliance comprising:

a capacitive flat sensor surface;

a transparent cover;

a printed circuit board having a cut-out and connected to the capacitive surface;

a light source mounted on a face of the printed circuit board opposite the transparent cover, wherein;

light transmission from the light source towards the transparent cover passes through the cut-out in the printed circuit board.

2. The touch switch according to claim 1, wherein the capacitive flat sensor surface is mounted on the face of the printed circuit board opposite the transparent cover.

3. The touch switch according to claim 1, wherein;

an auxiliary layer is interposed between the transparent cover, and

the printed circuit board and the auxiliary layer having a transparent zone facing the cut-out and comprising an opaque icon.

4. The touch switch according to claim 3, wherein the auxiliary layer is a polymeric film where the icon is obtained by serigraphy.

5. The touch switch according to claim 1, wherein the light source is a reversed mounted LED.

6. The touch switch according to claim 1, wherein the light source is an illuminated reverse mounted seven-segment display.

7. The touch switch according to claim 6, wherein the reverse mounted seven-segment display includes a plurality of metal pins welded to corresponding portions of the printed circuit board around the cut-out thereof.

8. The touch switch of claim 1, wherein the printed circuit board is fixed to the transparent cover by means of a non-conductive transparent adhesive.

9. The touch switch according to claim 1, further comprising:

a light guide mounted on the face of the printed circuit board opposite the transparent cover, wherein;

the light guide includes a protrusion located in the cut-out of the printed circuit board, this latter supporting a light source located in a corresponding seat adjacent the cut-out.

10. The touch switch according to claim 9, wherein:

a plastic film is interposed between the transparent cover and the printed circuit board, and

the film includes icons obtained by serigraphy.

11. The touch switch according to claim 9, further comprising:

a metal spring, wherein;

the transparent cover is detached from the printed circuit board, and

the metal spring is interposed between the transparent cover and the printed circuit board.

12. The touch switch according to claim 11, wherein:

an enlarged end of the metal spring is sandwiched between the printed circuit board and the light guide.

13. A touch switch for an electrical appliance, comprising:

a capacitive flat sensor surface;

a transparent cover;

a plastic support;

a printed circuit board interposed between the transparent cover and the plastic support and connected to the capacitive surface; and

a metal spring having an enlarged end, wherein;

the transparent cover is detached from the printed circuit board, and

the enlarged end of a metal spring is sandwiched between the printed circuit board and the plastic support.

14. The switch of claim 13, wherein the switch is placed on an electrical cooking appliance.