CAPACITIVE INPUT DEVICE INTERFERENCE DETECTION AND OPERATION

• US 20120262222A1
• Filed: 09/22/2011
• Published: 10/18/2012
• Est. Priority Date: 04/15/2011
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: SCHWARTZ, Adam, DATTALO, Tracy Scott, HODGSON, Robin
• Granted Patent: US 9,564,894 B2
• Time in Patent Office: Days
• US Class Current: 327/517
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

A processing system for a capacitive input device comprises sensor circuitry and control logic. The sensor circuitry is configured to be communicatively coupled with sensor electrodes of the capacitive input device. The control logic is configured to operate the capacitive input device in a first mode comprising interference sensing at a first level and input object sensing. The control logic is also configured to operate the capacitive input device in a second mode instead of in the first mode in response to: interference measured in the first mode meeting an interference condition; and a determination that input is in a sensing region of the capacitive input device. While operating in the second mode, interference sensing with the capacitive input device is either not performed or else is performed at a second level that is lower in fidelity than the first level.

Claims

1. A processing system for a capacitive input device, said processing system comprising:

sensor circuitry configured to be communicatively coupled with sensor electrodes of said capacitive input device; and

control logic configured to;

operate said capacitive input device in a first mode comprising interference sensing at a first level and input object sensing; and

operate said capacitive input device in a second mode instead of in said first mode in response to;

interference measured in said first mode meeting an interference condition; and

a determination that input is in a sensing region of said capacitive input device,

wherein, while in said second mode, interference sensing is either not performed or else performed at a second level that is lower in fidelity than said first level.

2. The processing system of claim 1, wherein said control logic is further configured to:

exit said second mode in response to a second determination while in said second mode that no input is in said sensing region.

3. The processing system of claim 1, wherein said control logic is further configured to:

enter said first mode in response to a second determination that no input has been sensed in said sensing region for a predetermined period.

4. The processing system of claim 1, wherein said control logic is further configured to:

enter said first mode in response to experiencing signal corruption while in said second mode.

5. The processing system of claim 1, wherein said control logic is further configured to:

operate said capacitive input device in a third mode in response to a second determination, said second determination comprising that no input has been sensed in said sensing region for a predetermined period, wherein input sensing is performed at a lower fidelity in said third mode than in said first mode.

6. The processing system of claim 5, wherein said control logic is further configured to:

operate said capacitive input device in said first mode in response to a third determination, said third determination comprising input being sensed in said sensing region while in said third mode.

7. The processing system of claim 1, wherein said control logic is further configured to:

implement an interference avoidance action while in said first mode in response to said interference condition not being met.

8. The processing system of claim 7, wherein said interference avoidance action is selected from the group of interference avoidance actions consisting of:

modifying a sensing frequency, modifying a filtering operation, increasing a code length utilized in a code division multiplexing sensing scheme, and implementing a non-linear filtering technique.

9. The processing system of claim 1, wherein interference sensing at a first level comprises:

interference sensing with transmitter electrodes of said capacitive input device in a non-transmitting state.

10. A capacitive input device comprising:

a plurality of sensor electrodes; and

a processing system coupled with said plurality of plurality of sensor electrodes, said processing system configured to;

operate said capacitive input device in a first mode comprising interference sensing at a first level and input object sensing; and

operate said capacitive input device in a second mode instead of in said first mode in response to;

interference measured in said first mode meeting an interference condition; and

a determination that input is in a sensing region of said capacitive input device,

wherein, while in said second mode, interference sensing is either not performed or else performed at a second level that is lower in fidelity than said first level.

11. The capacitive input device of claim 10, wherein said processing system is further configured to:

exit said second mode in response to a second determination while in said second mode that no input is in said sensing region.

12. The capacitive input device of claim 10, wherein said processing system is further configured to:

enter said first mode in response to a second determination that no input has been sensed in said sensing region for a predetermined period.

13. The capacitive input device of claim 10, wherein said processing system is further configured to:

enter said first mode in response to experiencing signal corruption while in said second mode.

14. The capacitive input device of claim 10, wherein said processing system is further configured to:

operate said capacitive input device in a third mode in response to a second determination, said second determination comprising that no input has been sensed in said sensing region for a predetermined period, wherein input sensing is performed at a lower fidelity in said third mode than in said first mode.

15. The capacitive input device of claim 14, wherein said processing system is further configured to:

enter said first mode in response to a third determination, said third determination comprising input being sensed in said sensing region while in said third mode.

16. A method of operating a capacitive input device configured to sense in a sensing region, said method comprising:

operating in a first mode, said first mode comprising interference sensing at a first level and input sensing; and

switching to operating in a second mode in response to;

interference measured while in said first mode satisfying an interference condition; and

a determination that input is in said sensing region,

wherein, while in said second mode, interference sensing is either not performed or else performed at a second level that is lower in fidelity than said first level.

17. The method as recited in claim 16, further comprising:

exiting said second mode in response to a second determination, said second determination comprising that no input is sensed in said sensing region.

18. The method as recited in claim 16, further comprising:

entering said first mode in response to a second determination, said second determination comprising no input being sensed in said sensing region for a predetermined period.

19. The method as recited in claim 16, further comprising:

entering said first mode in response to experiencing signal corruption while in said second mode.

20. The method as recited in claim 16, further comprising:

entering a third mode of operation in response to a second determination, said second determination comprising that no input has been sensed in said sensing region for a predetermined period, wherein input sensing is performed at a lower fidelity in said third mode than in said second mode.

21. The method as recited in claim 20, further comprising:

entering said first mode in response to a third determination, said third determination comprising input being sensed in said sensing region while in said third mode.

22. The method as recited in claim 16, wherein said operating in a first mode comprises:

implementing an interference avoidance action selected from the group of interference avoidance actions consisting of;

modifying a sensing frequency, modifying a filtering operation, increasing a code length utilized in a code division multiplexing sensing scheme, and implementing a non-linear filtering technique.

23. The method as recited in claim 16, wherein said operating in a first mode comprising interference sensing at a first level comprises:

performing said interference sensing at said first level with transmitter electrodes of said capacitive input device in a non-transmitting state.