Capacitive sensing during non-display update times

Patent metadata

Field	Value
Publication number	US-9330632-B2
Application number	US-201514755226-A
Country	US
Kind code	B2
Filing date	Jun 30, 2015
Priority date	Sep 7, 2011
Publication date	May 3, 2016
Grant date	May 3, 2016

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.

First claim

What is claimed is:

1. A processing system for a display device comprising an integrated capacitive sensing device, the processing system comprising:
a driver module comprising driver circuitry, the driver module coupled to 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 configured to be driven for updating a display of a display device and capacitive sensing during a display frame, wherein the display frame comprises a plurality of display line update periods, a first plurality of blanking periods and a second plurality of blanking periods, wherein each of the second plurality of blanking periods occurs between respective pairs of the plurality of display line update periods, and wherein each of the second plurality of blanking periods is longer than each of the first plurality of blanking periods; and
wherein the driver module is configured to drive a first sensor electrode of the plurality of sensor electrodes for capacitive sensing during a first one of the second plurality of blanking periods.

2. The processing system of claim 1 , wherein the driver module, when driving the first sensor electrode for capacitive sensing, is further configured to modulate the first sensor electrode to detect a capacitive coupling between the first sensor electrode and an input object.

3. The processing system of claim 1 , wherein the driver module, when driving the first sensor electrode for capacitive sensing, is further configured to drive the first sensor electrode with a transmitter signal.

4. The processing system of claim 3 further comprising:
a receiver module coupled to a second sensor electrode, the receiver module configured to receive resulting signals with the second sensor electrode, wherein the resulting signals comprise effects corresponding to the transmitter signal.

5. The processing system of claim 1 , wherein the driver module is further configured to drive at least a first one of the plurality of common electrodes during a first one of the first plurality of blanking periods for display updating.

6. The processing system of claim 1 , wherein the display frame further comprises a third blanking period, wherein the third blanking period occurs after a last one of the plurality of display line update periods.

7. The processing system of claim 1 , wherein each of the second plurality of blanking periods is at least as long as each of the plurality of display line update periods.

8. The processing system of claim 1 , wherein each of the plurality of sensor electrodes comprises at least two common electrodes of the plurality of common electrodes.

9. The processing system of claim 1 , wherein the processing system comprises:
a determination module configured to determine positional information for an input based on resulting signals received when the first sensor electrode is driven for capacitive sensing.

10. The processing system of claim 1 , wherein the first plurality of blanking periods outnumber the second plurality of blanking periods.

11. An input device comprising:
a plurality of sensor electrodes, each of the plurality of sensor electrodes comprises at least one common electrode of a plurality of common electrodes of a display device; and
a processing system coupled to the plurality of common electrodes, wherein the processing system is configured to:
drive the plurality of common electrodes for updating a display of the display device and capacitive sensing during a display frame, wherein the display frame comprises a plurality of display line update periods, a first plurality of blanking periods and a second plurality of blanking periods, wherein at least one of the first plurality of blanking periods and at least one of the second plurality of blanking periods occur between display line update periods of the plurality of display line update periods and wherein each of the second plurality of blanking periods is longer than each of the first plurality of blanking periods; and
drive a first sensor electrode of the plurality of sensor electrodes for capacitive sensing during a first one of the second plurality of blanking periods.

12. The input device of claim 11 , wherein the processing system, when driving the first sensor electrode for capacitive sensing, is further configured to modulate the first sensor electrode to detect a capacitive coupling between the first sensor electrode and an input object.

13. The input device of claim 11 , wherein the processing system, when driving the first sensor electrode for capacitive sensing, is further configured to drive the first sensor electrode with a transmitter signal, and wherein the processing system is further configured to receive resulting signals with a second sensor electrode of the plurality of sensor electrodes, and wherein the resulting signals comprise effects corresponding to the transmitter signal.

14. The input device of claim 11 , wherein the processing system is further configured to drive a first one of the plurality of common electrodes during a first one of the first plurality of blanking periods for display updating.

15. The input device of claim 11 , wherein the display frame further comprises a third blanking period, wherein the third blanking period occurs after all the first plurality of blanking periods.

16. The input device of claim 11 , wherein each of the second plurality of blanking periods is at least as long as each of the plurality of display line update periods.

17. The processing system of claim 1 , wherein the plurality of sensor electrodes are disposed as an array of rectangles.

18. A method for capacitive sensing, the method comprising:
driving a first sensor electrode of a plurality of sensor electrodes for capacitive sensing during a first one of a second plurality of blanking periods of a display frame, wherein the display frame further comprises a plurality of display line update periods, a first plurality of blanking periods and a third blanking period, and wherein each of the second plurality of blanking periods is longer than each of the first plurality of blanking periods and wherein each of the second plurality of blanking periods occurs between respective pairs of the plurality of display line update periods.

19. The method of claim 18 , wherein the third blanking period occurs after a last one of the plurality of display line update periods.

20. The method of claim 18 , further comprising:
driving a common electrode of the plurality of common electrodes for display updating during a first display line update period of the plurality of display line update periods and wherein each sensor electrode comprises at least one common electrode of the plurality of common electrodes.

Assignees

• Synaptics Inc

Inventors

• Shepelev Petr
• Schwartz Adam L

Classifications

• G06F3/0412 Primary

  Digitisers structurally integrated in a display · CPC title

• G09G5/18 Primary

  Timing circuits for raster scan displays (specially adapted for television H04N {; synchronisation between the display unit and other display units, videodisc player G09G5/12}) · CPC title

• G06F3/044

  by capacitive means · CPC title

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/04184

  Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally · CPC title