Mutual capacitance touch sensing device

• US 20080007539A1
• Filed: 08/01/2007
• Published: 01/10/2008
• Est. Priority Date: 07/06/2006
• Status: Active Grant

• Current Assignee: Steve Hotelling
• Original Assignee: Steve Hotelling
• Inventors: Hotelling, Steve
• Granted Patent: US 8,514,185 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/96077 comprising an electrode which is floating
• CPC Class Codes: H03K 2217/960775 Emitter-receiver or "fringe" type detection, i.e. one or more field emitting electrodes and corresponding one or more receiving electrodes

Abstract

A mutual capacitive touch sensing device is disclosed. The touch sensing device includes a mutual capacitive sensing controller having a plurality of distinct drive lines and a plurality of distinct sense lines; a source for driving a current or voltage separately though each drive line; and a mutual capacitance sensing circuit that monitors the capacitance at the sensing lines. The touch sensing device also includes a plurality of independent and spatially distinct mutual capacitive sensing nodes set up in a non two dimensional array. Each node includes a drive electrode that is spatially separated from a sense electrode. The drive electrode is coupled to one of the drive lines and the sense electrode is coupled to one of the sense lines. Each node is set up with a different combination of drive and sense line coupled thereto.

Claims

1. A touch sensing device, comprising:

a mutual capacitive sensing controller having a plurality of distinct drive lines and a plurality of distinct sense lines, a source for driving a current or voltage separately though each drive line, a mutual capacitance sensing circuit that monitors the capacitance at the sensing lines;

a plurality of independent and spatially distinct mutual capacitive sensing nodes set up in a non two dimensional array, each node including a drive electrode that is spatially separated from a sense electrode, the drive electrode being coupled to one of the drive lines and the sense electrode being coupled to one of the sense lines, each node being set up with a different combination of drive and sense line coupled thereto.

2. The touch sensing device as recited in claim 1 wherein the nodes are positioned next to one another in succession along a prescribed path.

3. The touch sensing device as recited in claim 2 wherein the nodes form a linear path.

4. The touch sensing device as recited in claim 2 wherein the nodes form a circular path.

5. The touch sensing device as recited in claim 4 wherein the nodes represent angular input areas disposed around a circle.

6. The touch sensing device as recited in claim 2 wherein the nodes are placed in an open loop arrangement.

7. The touch sensing device as recited in claim 2 wherein the nodes are placed in a closed loop arrangement.

8. The touch sensing device as recited in claim 1 wherein a portion of the nodes form a scrolling region

9. The touch sensing device as recited in claim 1 wherein a portion of the nodes form buttons that represent distinct button functions.

10. The touch sensing device as recited in claim 1 further including a filter that rejects parasitic capacitance effects so that a clean representation of the charge transferred across the node is outputted.

11. The touch sensing device as recited in 1 wherein the nodes include a cover film, an electrode layer and a substrate, the cover film being disposed over the electrode layer, the electrode layer being disposed over the substrate, the electrode layer including the drive and sense electrodes.

12. The touch sensing device as recited in 1 wherein the drive and sense electrodes are juxtaposed plates.

13. The touch sensing device as recited in 1 wherein the drive and sense electrode are interleaved with one another.

14. The touch sensing device as recited in 1 further including a floating electrode disposed over and spatially separated from the electrode pair of the node.

15. The touch sensing device as recited in 1 wherein the mutual capacitance sensing circuit continuously monitors all the sensing lines at the same time.

16. The touch sensing device as recited in 1 wherein the mutual capacitance sensing circuit monitors all the sensing lines sequentially.

17. The touch sensing device as recited in 1 wherein the number of nodes is equal to the number of drive lines multiplied by the number of sense lines.

18. The touch sensing device as recited in 17 wherein the number of drive lines is equal to the number of sense lines.

19. The touch sensing device as recited in 17 wherein the number of drive lines is different than the number of sense lines.

20. The touch sensing device as recited in 1 wherein the number of nodes is less than the number of drive lines multiplied by the number of sense lines.

21. A mutual capacitive sensing method, comprising:

separately driving a voltage or current through each drive line;

capacitively coupling current between drive electrodes that are coupled to driven drive line and corresponding sense electrodes that are coupled to sense lines;

detecting capacitance at electrode pairs through each sense line each time a drive line is driven;

determining which electrode pairs have been touched based on detected capacitance; and

performing actions based on which electrode pairs have been touched.

22. The method as recited in claim 21 further including filtering parasitic capacitance created by non driven electrode pairs.

23. A touch sensing device that operates via mutual capacitance, comprising:

a mutual capacitance sensing node including a drive electrode that is spatially separated and juxtaposed next to a sense electrode, the drive electrode being coupled to a drive line and the sense electrode being coupled to a sense line of a mutual capacitance sensing circuit.

24. A mutual capacitance touch sensing device, comprising:

a plurality of mutual capacitance sensing nodes arranged in a non 2D array.