Capacitive sensing with combinatorial sensor layout

• US 7,990,160 B2
• Filed: 05/22/2009
• Issued: 08/02/2011
• Est. Priority Date: 05/22/2009
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Reynolds, Joseph K
• Primary Examiner(s): TANG, MINH NHUT
• Application Number:
  US12/471,206
• Publication Number:
  US 20100295564A1
• Time in Patent Office: 802 Days
• Field of Search: None
• US Class Current: 324/686
• 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: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03M 11/20 Dynamic coding, i.e. by key scanning H03M11/26 takes precedence

Abstract

In a method for determining capacitance, a set of sensor electrodes is employed. The set of sensor electrodes comprises at least three sensor electrodes including first, second, and third sensor electrodes. The first sensor electrode meets the second sensor electrode at a first activation region of a plurality of activation regions. The first sensor electrode meets the third sensor at a second activation region of the plurality of activation regions. The second sensor electrode meets the third sensor electrode at a third activation region of the plurality of activation regions. The third sensor electrode transmits while first indicia are received with the first and the second sensor electrodes. The first sensor electrode transmits while second indicia are received with the second sensor electrode. Capacitances associated with the first, second and third activation regions are determined using at least the first indicia and second indicia.

Claims

1. A method for determining capacitance, said method comprising:

employing a set of sensor electrodes, said set of sensor electrodes comprising at least three sensor electrodes, wherein a first sensor electrode of said set of sensor electrodes meets a second sensor electrode of said set of sensor electrodes at a first activation region of a plurality of activation regions, wherein said first sensor electrode meets a third sensor electrode of said set of sensor electrodes at a second activation region of said plurality of activation regions, and wherein said second sensor electrode meets said third sensor electrode at a third activation region of said plurality of activation regions;

transmitting with said third sensor electrode while receiving first indicia with said first and said second sensor electrodes;

transmitting with said first sensor electrode while receiving second indicia with said second sensor electrode; and

determining capacitances associated with said first, said second and said third activation regions using at least said first indicia and said second indicia.

2. The method as recited in claim 1, wherein said set of sensor electrodes further comprises a fourth sensor electrode, and wherein said fourth sensor electrode meets at least one of said first, second and third sensor electrodes at a fourth activation region of said plurality of activation regions, and wherein said method further comprises:

receiving with said third sensor electrode.

3. The method as recited in claim 1, wherein said transmitting with said third sensor electrode while receiving first indicia with said first and said second sensor electrodes comprises:

transmitting on a one-at-a-time basis with only said third sensor electrode of said set of sensor electrodes.

4. The method as recited in claim 1, wherein said transmitting with said third sensor electrode while receiving first indicia with said first and said second sensor electrodes comprises:

receiving with said first and said second sensor electrodes of said set of sensor electrodes on a one-at-a-time basis.

5. The method as recited in claim 1, wherein said transmitting with said third sensor electrode while receiving first indicia with said first and said second sensor electrodes comprises:

concurrently receiving with both said first and said second sensor electrodes.

6. The method as recited in claim 1, wherein said transmitting with said third sensor electrode and said transmitting with said first sensor electrode overlap for at least a portion of time.

7. The method as recited in claim 1, wherein said transmitting with said first sensor electrode while receiving second indicia with said second sensor electrode comprises:

transmitting on a one-at-a-time basis with only said first sensor electrode of said set of sensor electrodes.

8. The method as recited in claim 1, wherein said method for determining capacitance further comprises:

transmitting with one of said at least three sensor electrodes, while receiving with said one of said at least three sensor electrodes.

9. A method for providing a capacitance sensing device, said method comprising:

providing a set of sensor electrodes, said set of sensor electrodes comprising at least three sensor electrodes, wherein a first sensor electrode of said set of sensor electrodes meets a second sensor electrode of said set of sensor electrodes at a first activation region of a plurality of activation regions, wherein said first sensor electrode meets a third sensor electrode of said set of sensor electrodes at a second activation region of said plurality of activation regions, and wherein said second sensor electrode meets said third sensor electrode at a third activation region of said plurality of activation regions;

providing a plurality of sensor channels;

ohmically coupling a first sensor channel of said plurality of sensor channels to said first sensor electrode;

ohmically coupling a second sensor channel of said plurality of sensor channels to said second sensor electrode; and

ohmically coupling a third sensor channel of said plurality of sensor channels to said third sensor electrode, wherein said first sensor channel is configured to both transmit and receive electrical signals, wherein said device is configured such that first indicia for sensing capacitances associated with said plurality of activation regions is received with said first and second sensor channels while said third sensor channel transmits and wherein said device is further configured such that second indicia for sensing capacitances associated with said plurality of activation regions is received with said second sensor channel while said first sensor channel transmits.

10. The method as recited in claim 9, wherein said providing a plurality of sensor channels comprises:

providing said plurality of sensor channels wherein multiple ones of said plurality of sensor channels are each configured to both transmit and receive electrical signals for sensing capacitances associated with multiple activation regions of said plurality of activation regions.

11. The method as recited in claim 9, further comprising:

providing a controller comprising said plurality of sensor channels, said controller configured to transmit on a one-at-a-time basis with sensor channels of said plurality of sensor channels.

12. The method as recited in claim 9, further comprising:

providing a controller comprising said plurality of sensor channels, said controller configured to receive on a one-at-a-time basis with sensor channels of said plurality of sensor channels.

13. The method as recited in claim 9, further comprising:

providing a controller comprising said plurality of sensor channels, said controller configured to receive concurrently with sensor channels of said plurality of sensor channels.

14. The method as recited in claim 9, further comprising:

providing a controller comprising said plurality of sensor channels, said controller configured to transmit with said third sensor channel and to receive concurrently with both said first and said second sensor channels.

15. A capacitive sensing device comprising:

a set of sensor electrodes comprising;

a first sensor electrode of said set of sensor electrodes;

a second sensor electrode of said set of sensor electrodes, wherein said first sensor electrode meets said second sensor electrode at a first activation region of a plurality of activation regions; and

a third sensor electrode of said set of sensor electrodes, wherein said first sensor electrode meets said third sensor electrode at a second activation region of said plurality of activation regions, and wherein said second sensor electrode meets said third sensor electrode at a third activation region of said plurality of activation regions; and

a controller, said controller comprising a plurality of sensor channels, wherein a first sensor channel of said plurality of sensor channels is ohmically coupled to said first sensor electrode, a second sensor channel of said sensor plurality of channels is ohmically coupled to said second sensor electrode, and a third sensor channel of said plurality of sensor channels is ohmically coupled to said third sensor electrode, wherein said first sensor channel is configured to both transmit and receive electrical signals, and wherein the controller is configured such that first indicia for sensing capacitances associated with said plurality of activation regions is received with said first and second sensor channels while said third sensor channel transmits and wherein the controller is further configured such that second indicia for sensing capacitances associated with said plurality of activation regions is received with said second sensor channel while said first sensor channel transmits.

16. The capacitive sensing device of claim 15, wherein at least one of said first, second, and third sensor electrodes comprises a deflectable structure.

17. The capacitive sensing device of claim 15, wherein said plurality of activation regions comprises an activation region defined by an interdigitation of at least two sensor electrodes of said set of sensor electrodes.

18. The capacitive sensing device of claim 15, wherein said plurality of activation regions comprises an activation region defined by a crossing of at least two sensor electrodes of said set of sensor electrodes.

19. The capacitive sensing device of claim 15, wherein said plurality of activation regions is greater in number than said plurality of sensor channels.

20. The capacitive sensing device of claim 15, wherein multiple sensor channels of said plurality of sensor channels are configured to both transmit and receive electrical signals for sensing capacitances associated with said plurality of activation regions.

21. The capacitive sensing device of claim 15, wherein said set of sensor electrodes is arranged in a manner requiring the use of only two conductive layers of said capacitive sensing device.

22. The capacitive sensing device of claim 15, wherein said controller is configured to transmit on a one-at-a-time basis with sensor channels of said plurality of sensor channels.

23. The capacitive sensing device of claim 15, wherein said controller is configured to concurrently receive with multiple sensor channels of said plurality of sensor channels.