Sensing during non-display update time to avoid interference

• US 9,786,254 B2
• Filed: 02/24/2011
• Issued: 10/10/2017
• Est. Priority Date: 02/26/2010
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Reynolds, Joseph Kurth, Shahparnia, Shahrooz, Schwartz, Adam, Jordan, Joel
• Primary Examiner(s): Rayan, Mihir K
• Application Number:
  US13/034,696
• Publication Number:
  US 20110210941A1
• Time in Patent Office: 2,420 Days
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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: G09G 5/18 Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12

Abstract

In a method of capacitive sensing using an integrated capacitive sensor device and display device, a transmitter signal is transmitted with a combination electrode of the integrated capacitive sensor device and display device. The combination electrode is configured for both capacitive sensing and display updating. The transmitter signal transitions at least twice during a non-display update time period associated with row update of the display device. A display of the display device is updated during an update time period. A resulting signal is received with a receiver electrode of the integrated capacitive sensor device and display device during the non-display update time period. The resulting signal corresponds to the transmitter signal.

Claims

1. A method of capacitive sensing using an integrated capacitive sensor device and display device, said method comprising:

transmitting a transmitter signal with a combination electrode of said integrated capacitive sensor device and display device, said combination electrode configured for both capacitive sensing and display updating, wherein said transmitter signal transitions at least twice during a non-display update time period associated with a row update of a display frame of said display device;

updating a display of said display device during a first update time period of said display frame occurring prior to said non-display update time period;

updating said display during a second update time period of said display frame occurring subsequent to said non-display update time period;

receiving a first resulting signal with a receiver electrode of said integrated capacitive sensor device and display device during said non-display update time period, wherein said first resulting signal corresponds to said transmitter signal;

acquiring a first demodulated output by demodulating said first resulting signal in a first way;

acquiring a second demodulated output by demodulating said first resulting signal in a second way, wherein said second way and said first way differ; and

shifting, based at least in part upon an amount of interference, from using said first demodulated output for determining positional information to using said second demodulated output for determining positional information,

wherein said amount of interference is based on a measurement of a third demodulated output, wherein said third demodulated output is acquired by demodulating a second resulting signal in one of said first way and said second way, and wherein said second resulting signal is received by said receiver electrode during a time period when no transmitter signal is transmitted with said combination electrode.

2. The method as recited in claim 1, further comprising:

determining a first measurement of a change in a transcapacitive coupling between said combination electrode and said receiver electrode based on said first or second resulting signal; and

determining said positional information based on said first measurement.

3. The method as recited in claim 1, further comprising:

determining a measurement of a change in transcapacitive coupling between said combination electrode and said receiver electrode based on said first demodulated output when said amount of interference does not exceed a first amount; and

using said measurement of said change in determining said positional information.

4. The method as recited in claim 1, further comprising:

determining a measurement of a change in transcapacitive coupling between said combination electrode and said receiver electrode based on said second demodulated output when said amount of interference exceeds a first amount; and

using said measurement of said change in determining said positional information.

5. The method as recited in claim 1, wherein said transmitter signal has a first frequency, said method further comprising:

shifting from transmitting said transmitter signal having said first frequency to transmitting a second transmitter signal having a second frequency by changing a duration of said at least one non-display update time period of said display device, wherein said shifting occurs based at least in part upon said amount of interference.

6. The method as recited in claim 5, wherein said changing said duration of said at least one non-display update time period comprises:

increasing said duration of said non-display update time period associated with row updates of said display device.

7. The method as recited in claim 5, wherein said changing said duration of said at least one non-display update time period comprises:

decreasing said duration of said non-display update time period associated with row updates of said display device.

8. The method as recited in claim 1, wherein said transmitting said transmitter signal comprises:

transmitting said transmitter signal as a display update signal for updating said display device of said integrated capacitive sensor device and display device.

9. A processing system comprising:

transmitter circuitry configured to transmit a transmitter signal with a combination electrode of an integrated capacitive sensor device and display device during a non-display update time period associated with a first row update of a display within a display frame of said display device, wherein said transmitter signal transitions at least two times during said non-display update time period associated with said first row update of said display device, wherein said transmitter signal is transmitted between said first row update and a second row update of said display frame, and wherein said combination electrode is configured for both capacitive sensing and display updating; and

receiver circuitry configured to receive a first resulting signal with a receiver electrode during said non-display update time period, wherein said first resulting signal corresponds to said transmitter signal;

demodulation circuitry configured to;

acquire a first demodulated output by demodulating said first resulting signal in a first way; and

acquire a second demodulated output by demodulating said first resulting signal in a second way, wherein said second way and said first way differ; and

a demodulation type selector configured to shift, based at least in part upon an amount of interference, said demodulation circuitry from using said first demodulated output for determining positional information to using said second demodulated output for determining positional information,

wherein said amount of interference is based on a measurement of a third demodulated output, wherein said third demodulated output is acquired by demodulating a second resulting signal in one of said first way and said second way, and wherein said second resulting signal is received by said receiver electrode during a time period when no transmitter signal is transmitted with said combination electrode.

10. The processing system of claim 9, wherein said processing system is configured to:

determine a first measurement of a transcapacitive coupling between said combination electrode and said receiver electrode based on said first or second resulting signal; and

use said first measurement in determining positional information.

11. The processing system of claim 9, wherein said transmitter circuitry is configured to:

transmit a display update signal for said display device, wherein said display update signal is transmitted with said combination electrode.

12. The processing system of claim 9, wherein said processing system is configured to utilize said transmitter circuitry to transmit said transmitter signal having a first frequency;

and wherein said processing system further comprises;

a duration changer configured for changing a duration of at least one non-display update time period of said display device, wherein said change in duration causes said transmitter circuitry to shift from transmitting said transmitter signal with said combination electrode to transmitting a second transmitter signal with said combination electrode, wherein said second transmitter signal has a second frequency, wherein said change does not substantially change a refresh rate of said display device, and wherein said change occurs based at least in part upon said amount of interference.

13. A touch screen device comprising:

a display device, said display device comprising a combination electrode configured for both display updating and touch sensing;

a receiver electrode proximate said combination electrode, said receiver electrode configured for touch sensing; and

a processing system communicatively coupled with said display device, said processing system configured to;

transmit a transmitter signal with said combination electrode during a non-display update time period associated with a first row update of a display within a display frame of said display device, wherein said transmitter signal is transmitted between said first row update and a second row update of said display frame, and wherein said transmitter signal transitions at least two times during said non-display update time period associated with said first row update of said display device;

receive a first resulting signal with said receiver electrode during said non-display update time period, said first resulting signal corresponds to said transmitter signal;

acquire a first demodulated output by demodulating said first resulting signal in a first way;

acquire a second demodulated output by demodulating said first resulting signal in a second way, wherein said second way and said first way differ; and

shift, based at least in part upon an amount of interference, from using said first demodulated output for determining positional information to using said second demodulated output for determining positional information,

wherein said amount of interference is based on a measurement of a third demodulated output, wherein said third demodulated output is acquired by demodulating a second resulting signal in one of said first way and said second way, and wherein said second resulting signal is received by said receiver electrode during a time period when no transmitter signal is transmitted with said combination electrode.

14. The touch screen device of claim 13, wherein said processing system is configured to:

determine a measurement of change in a transcapacitive coupling between said combination electrode and said receiver electrode based on said first or second resulting signal; and

determine said positional information based on said measurement of said change.

15. The touch screen device of claim 13, wherein said processing system is configured to:

transmit a display update signal for said display device, wherein said display update signal is transmitted with said combination electrode.

16. The touch screen device of claim 13, wherein said processing system is configured to:

transmit said transmitter signal having a first frequency; and

change a duration of said at least one non-display update time period of said display device, wherein said change in duration causes a shift from transmitting said transmitter signal with said combination electrode to transmitting a second transmitter signal with said combination electrode, wherein said second transmitter signal has a second frequency, and wherein said change does not substantially change a refresh rate of said display device, and wherein said change occurs based at least in part upon said amount of interference.