Reduction of touch-sensor interference from active display

• US 8,917,249 B1
• Filed: 08/05/2010
• Issued: 12/23/2014
• Est. Priority Date: 08/05/2010
• Status: Expired due to Fees

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Buuck, David C., Depew, John Matthew
• Primary Examiner(s): BALAOING, ARIEL A
• Application Number:
  US12/851,029
• Time in Patent Office: 1,601 Days
• Field of Search: 345/173, 178/18.02
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally

Abstract

An interference suppression module coordinates devices susceptible to interference such as a touch sensor with potentially interference generating devices such as a display drive matrix, an active haptic device, and so forth. As a result of status signals generated by the interference suppression module, controllers of the susceptible devices may modify the input received to mitigate or avoid interference.

Claims

1. An electronic device comprising:

a processor;

a touch sensor coupled to a touch sensor controller that is coupled to the processor;

an active display coupled to a display controller that is coupled to the processor;

a memory coupled to the processor; and

an interference suppression module stored within the memory and executable on the processor to;

determine whether a display update of the display by the display controller is in progress;

configure the touch sensor controller to disregard input received from the touch sensor when the display update is in progress; and

configure the touch sensor controller to weight the input received from the touch sensor when the display update is not in progress and a noise signal exceeds a noise threshold associated with interference from an interference generating component other than the display controller, wherein the input is assigned a lower weight with respect to input that is received when the noise signal does not exceed the noise threshold.

2. The electronic device of claim 1, wherein the touch sensor controller is further configured to maintain the input received from the touch sensor without modification when the display update is not in progress and the noise signal does not exceed the noise threshold.

3. The electronic device of claim 1, wherein the active display comprises at least one of:

a liquid crystal display, a light emitting diode display, or a plasma display.

4. The electronic device of claim 1, wherein the input received from the touch sensor comprises a touch input event.

5. The electronic device of claim 4, wherein the weighting occurs for a pre-determined time interval after the interference suppression module configures the touch sensor controller to weight the input received from the touch sensor.

6. The electronic device of claim 1, wherein the touch sensor comprises at least one of:

a capacitive touch array;

a projected capacitance touch array;

a resistive touch array;

an interpolating force sensitive resistor array;

an optical touch sensor;

or

an acoustic touch sensor.

7. The electronic device of claim 1, wherein the display controller is configured to generate a status signal for use, at least in part, by the interference suppression module to determine whether the display update of the display is in progress and whether the noise signal exceeds the noise threshold associated with interference from an interference generating component other than the display controller.

8. The electronic device of claim 7, wherein the display controller is configured to generate the status signal before the display update takes place.

17. The electronic device of claim 1, wherein:

the interference generating component other than the display controller includes a haptic controller coupled to the touch sensor controller; and

the interference includes haptic output from the haptic controller that exceeds the noise threshold and that is received during a time interval when the display controller is waiting for a next display update.

18. The electronic device of claim 1, wherein the interference suppression module is further executable on the processor to:

configure the touch sensor controller to activate scanning of the touch sensor when the display update is not in progress; and

configure the touch sensor controller to deactivate scanning of the touch sensor when the display update is in progress, the deactivation to reduce power consumption associated with scanning of the touch sensor.

9. A non-transitory computer-readable storage medium storing instructions that, when executed, instruct a processor to perform acts comprising:

coordinating a touch sensor controller coupled to a touch sensor with an output device controller, the output device controller being coupled to one or more output devices;

receiving touch input from the touch sensor;

disregarding the touch input received from the touch sensor during output via the one or more output devices; and

weighting the touch input received from the touch sensor during periods free from the output when a noise signal exceeds a noise threshold associated with interference from an interference generating component, wherein the touch input received during periods free from the output is assigned a lower weight with respect to touch input that is received during periods free from the output when the noise signal does not exceed the noise threshold.

10. The non-transitory computer-readable storage medium of claim 9, wherein the output device controller comprises a display controller of an active display.

11. The non-transitory computer-readable storage medium of claim 9, wherein the coordinating comprises synchronizing the touch sensor controller and the output device controller such that touch input is accepted without modification during periods free from the output when the noise signal does not exceed the noise threshold.

12. A method comprising:

determining whether an active display update of a display by a display controller is in progress;

configuring a touch sensor controller to tag input received from a touch sensor as unreliable and disregard the input when the active display update is in progress;

configuring the touch sensor controller to tag input received from the touch sensor as suspect when the active display update is not in progress and a noise signal exceeds a noise threshold associated with interference from an interference generating component; and

configuring the touch sensor controller to tag input received from the touch sensor as reliable when the active display update is not in progress and the noise signal does not exceed the noise threshold, wherein input that is tagged as suspect is assigned a lower weight with respect to input that is received when the noise signal does not exceed the noise threshold; and

determining whether to modify output from the touch sensor controller based at least in part upon the tag.

13. The method of claim 12, further comprising accepting unmodified input received from the touch sensor while the active display update is not in progress and the input is tagged as reliable when the noise signal does not exceed the noise threshold.

14. A method comprising:

identifying one or more interfering events;

generating a status signal;

in response to the status signal, configuring a touch sensor controller to modify input received from a touch sensor;

completing one or more potentially interfering events; and

in response to the completing;

configuring the touch sensor controller to receive input from the touch sensor without modification in response to the input being identified as reliable when a noise signal does not exceed a noise threshold associated with interference from an interference generating component; and

configuring the touch sensor controller to modify the input received from the touch sensor in response to the input being identified as suspect when the noise signal exceeds the noise threshold, wherein the suspect input is assigned a lower weight with respect to reliable input and modified based on the lower assigned weight.

15. The method of claim 14, wherein the input received from the touch sensor comprises a touch input event.

16. The method of claim 15, wherein the weighting occurs for a pre-determined time interval.