Method for implementing capacitive sensing in the presence of conductive decorative materials

• US 8,629,364 B2
• Filed: 03/01/2010
• Issued: 01/14/2014
• Est. Priority Date: 03/01/2010
• Status: Active Grant

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Krier, James Frederick, Whitton, David Michael
• Primary Examiner(s): Hammond, Briggitte R
• Application Number:
  US12/714,681
• Publication Number:
  US 20110209976A1
• Time in Patent Office: 1,415 Days
• Field of Search: 200/600, 200/512, 200310-317
• US Class Current: 200/600
• CPC Class Codes: G06F 1/1671 Special purpose buttons or auxiliary keyboards, e.g. retractable mini keypads, keypads or buttons that remain accessible at closed laptop G06F1/1666 takes precedence
• CPC Class Codes: G06F 3/021 Arrangements integrating additional peripherals in a keyboard, e.g. card or barcode reader, optical scanner
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches
• CPC Class Codes: Y10T 29/43 Electric condenser making
• CPC Class Codes: Y10T 29/435 Solid dielectric type
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

A control panel is disclosed. The control panel includes an electrically conductive substrate having a front surface. A first dielectric layer is disposed on the front surface of the substrate. A first electrode layer is disposed on a front surface of the first dielectric layer, wherein the first dielectric layer electrically isolates the first electrode layer from the substrate. The first electrode layer is in electrical communication with a switch circuit adapted to detect a change in a capacitance of the first electrode layer. A substantially transparent film can be provided to cover the electrode. The front surface of the substrate is a decorative surface substantially visible through the first dielectric layer, the first electrode layer, and the film.

Claims

1. A control panel comprising:

an electrically conductive substrate having a front surface, wherein the substrate is electrically grounded;

a first dielectric layer disposed on the front surface of the substrate; and

a first electrode layer disposed on a front surface of the first dielectric layer and electrically isolated from the substrate, wherein the first electrode layer is in electrical communication with a switch circuit adapted to detect a change in a capacitance of the first electrode layer, and wherein the front surface of the substrate is a decorative surface substantially visible through the first dielectric layer and the first electrode layer.

2. The control panel according to claim 1, wherein the first dielectric layer is produced from at least one layer of a polymer film.

3. The control panel according to claim 1, wherein the first electrode layer is produced from indium tin oxide.

4. The control panel according to claim 1, wherein the substrate includes a base layer abutting an electrically conductive layer, the electrically conductive layer being electrically grounded and including the front surface of the substrate.

5. The control panel according to claim 1, wherein at least one of the first dielectric layer, the first electrode layer, the second dielectric layer, the second electrode layer, and the film is one of substantially transparent and substantially translucent.

6. The control panel according to claim 1, wherein the front surface of the substrate is metallic.

7. The control panel according to claim 1, further comprising a substantially transparent film covering the first electrode layer.

8. The control panel according to claim 7, wherein the film is formed from at least one of a polyester, a polycarbonate, a polyethylene, a polyethersulfone, an acrylic, and a plastic resin.

9. The control panel according to claim 1, further comprising a second dielectric layer disposed on the first electrode layer and a second electrode layer disposed on the second dielectric layer.

10. The control panel according to claim 9, wherein the front surface of the substrate is a decorative surface substantially visible through the first dielectric layer, the first electrode layer, the second dielectric layer, and the second electrode layer.

11. The control panel according to claim 9, wherein the entire first electrode layer is electrically isolated from the second electrode layer.

12. A control panel comprising:

an electrically conductive substrate having a front surface, wherein the substrate is electrically grounded;

a first dielectric layer disposed on the front surface of the substrate;

a first electrode layer disposed on a front surface of the first dielectric layer and electrically isolated from the substrate, the first electrode layer in electrical communication with a switch circuit adapted to detect a change in a capacitance of the first electrode layer;

a second dielectric layer disposed on a front surface of the first electrode layer;

a second electrode layer disposed on a front surface of the second dielectric layer; and

a film covering the second electrode layer, wherein the front surface of the substrate is a decorative surface substantially visible through the first dielectric layer, the first electrode layer, the second dielectric layer, the second electrode layer, and the film.

13. The control panel according to claim 12, wherein the first dielectric layer is formed from at least one layer of a polymer film.

14. The control panel according to claim 12, wherein the first electrode layer is produced from indium tin oxide.

15. The control panel according to claim 12, wherein the film layer is formed from at least one of a polyester, a polycarbonate, a polyethylene, a polyethersulfone, an acrylic, and a plastic resin.

16. The control panel according to claim 12, wherein the substrate includes a base layer and an electrically conductive layer, the electrically conductive layer being electrically grounded and including the front surface of the substrate.