Distributed blanking for touch optimization

• US 9,576,557 B2
• Filed: 01/12/2015
• Issued: 02/21/2017
• Est. Priority Date: 09/07/2011
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Lillie, Jeffrey S., Childs, John, Ludden, Christopher A., Mackin, Thomas, Shepelev, Petr
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): Sarma, Abhishek
• Application Number:
  US14/595,049
• Publication Number:
  US 20150123944A1
• Time in Patent Office: 771 Days
• Field of Search: 345/104, 345/173, 345/174, 348/634, 348/E3.047, 725/37, 725/87, 725/89, 725/100
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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

Embodiments of the invention generally provide an input device with display screens that periodically update (refresh) the screen by selectively driving common electrodes corresponding to pixels in a display line. In general, the input devices drive each electrode until each display line (and each pixel) of a display frame is updated. In addition to updating the display, the input device may perform capacitive sensing using the display screen as a proximity sensing area. To do this, the input device may interleave periods of capacitive sensing between periods of updating the display based on a display frame. For example, the input device may update the first half of display lines of the display screen, pause display updating, perform capacitive sensing, and finish updating the rest of the display lines. Further still, the input device may use common electrodes for both updating the display and performing capacitive sensing.

Claims

1. A processing system for an input device comprising a display device, the processing system comprising:

a display driver comprising display driver circuitry, the display driver configured to;

couple to a plurality of common electrodes of the display device, wherein the plurality of common electrodes is configured for display updating and capacitive sensing,

receive display frame updates, and

drive first common electrodes of the plurality of common electrodes for display updating, during a first time period of a first display frame, in accordance with at least a first portion of the display frame updates; and

a touch driver configured to;

couple to a plurality of sensor electrodes, and

drive a first sensor electrode of the plurality of sensor electrodes for capacitive sensing during a second time period of the first display frame, and wherein the first sensor electrode comprises at least one of the plurality of common electrodes,

wherein the display driver is configured to drive at least second common electrodes of the plurality of common electrodes for updating, during a third time period of the first display frame, the display device based on at least a second portion of the display frame updates, wherein the second time period occurs after the first time period and before the third time period,

wherein the display driver is further configured to control receipt of the display frame updates during the second time period.

2. The processing system of claim 1, wherein driving the first sensor electrode for capacitive sensing comprises modulating the first sensor electrode for absolute capacitive sensing.

3. The processing system of claim 1, wherein driving the first sensor electrode for capacitive sensing comprises driving the first sensor electrode with a transmitter signal.

4. The processing system of claim 3 further comprising:

receiver circuitry coupled to a second sensor electrode of the plurality of sensor electrodes, the receiver circuitry configured to receive a resulting signal with the second sensor electrode, wherein the resulting signal comprises effects corresponding to the transmitter signal.

5. The processing system of claim 1, wherein at least a portion of the display driver and at least a portion of the touch driver are parts of a single integrated controller.

6. The processing system of claim 1, wherein the second time period is at least as long as the first time period.

7. The processing system of claim 1, wherein controlling receipt of the display frame updates comprises communicating with a video source using a first control signal, the first control signal configured to pause transmission of the display frame updates by the video source.

8. The processing system of claim 7, wherein communicating with the video source using the first control signal comprises transmitting the first control signal to the video source from the processing system before the second time period, and wherein the touch driver is further configured to drive the first sensor electrode for capacitive sensing while transmission of the display frame updates is paused.

9. The processing system of claim 7, wherein the display driver is further configured to transmit a resume signal to the video source indicating that the display driver is ready to receive the second portion of the display frame updates.

10. The processing system of claim 7, wherein controlling receipt of the display frame updates to pause updating the display device comprises switching from updating the display device during the first time period to performing capacitive sensing during the second time period in response to a second control signal received by the display driver from the video source.

11. The processing system of claim 7, controlling receipt of the display frame updates to pause updating of the display device comprises buffering the second portion of the display frame updates during the second time period.

12. The processing system of claim 1, wherein the display driver is further configured to pause updating the display device during the second time period.

13. A method for operating a display device comprising:

receiving display frame updates for updating the display device;

driving first common electrodes of a plurality of common electrodes for updating the display device in accordance with at least a first portion of the display frame updates during a first time period of a first display frame;

driving a first sensor electrode of a plurality of sensor electrodes for capacitive sensing during a second time period of the first display frame, the first sensor electrode comprising at least one of the plurality of common electrodes;

driving second common electrodes of the plurality of common electrodes for updating, during a third time period of the first display frame, the display device based on at least a second portion of the display frame updates, wherein the second time period occurs after the first time period and before the third time period; and

controlling receipt of the display frame updates during the second time period.

14. The method of claim 13, wherein driving the first sensor electrode for capacitive sensing comprises driving a modulated signal on the first sensor electrode for absolute capacitive sensing.

15. The method of claim 13, wherein driving the first sensor electrode for capacitive sensing comprises driving the first sensor electrode with a transmitter signal, and wherein the method further comprises:

receiving resulting signals with a second sensor electrode, wherein the resulting signals comprise effects corresponding to the transmitter signal.

16. The method of claim 13, wherein the second time period is at least as long as the first time period.

17. The method of claim 13, wherein controlling receipt of the display frame updates further comprises communicating with a video source using a control signal, the control signal configured to pause transmission of the display frame updates by the video source.

18. The method of claim 17, wherein controlling receipt of the display frame updates further comprises:

transmitting a resume signal to the video source.

19. The method of claim 17, wherein controlling receipt of the display frame updates further comprises:

buffering the second portion of the display frame updates for the first display frame during the second time period.

20. The method of claim 13 further comprising:

pausing updating the display device during the second time period.

21. An input device comprising:

a plurality of sensor electrodes, wherein each of the plurality of sensor electrodes comprises at least one common electrode of a plurality of common electrodes, wherein the plurality of common electrodes is configured to be operated for capacitive sensing and to be operated for updating a display device; and

a processing system coupled to the plurality of common electrodes, the processing system configured to;

receive display frame updates for updating the display device;

drive first common electrodes of the plurality of common electrodes for updating, during a first time period of a first display frame, the display device based on at least a first portion of the display frame updates;

drive a first sensor electrode of the plurality of sensor electrodes for capacitive sensing during a second time period of the first display frame;

drive second common electrodes of the plurality of common electrodes for updating the display device based on at least a second portion of the display frame updates during a third time period of the first display frame, wherein the second time period occurs after the first time period and before the third time period; and

control receipt of the display frame updates during the second time period.

22. The input device of claim 21, wherein controlling receipt of the display frame updates comprises:

communicating with a video source using a control signal, the control signal is configured to pause transmission of the display frame updates by the video source.

23. The input device of claim 22 further comprising:

a memory element, and wherein controlling receipt of the display frame updates comprises;

buffering, in the memory element, the second portion of the display frame updates for the first display frame during at least a portion of the second time period in response to the display frame updates being paused.

24. The input device of claim 21, wherein the second time period is at least as long as the first time period.

25. The input device of claim 21, wherein the processing system is further configured to pause updating the display device during the second time period.