Capacitive sensing during non-display update times

Patent metadata

Field	Value
Publication number	US-9324301-B2
Application number	US-201514755200-A
Country	US
Kind code	B2
Filing date	Jun 30, 2015
Priority date	Sep 7, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 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 configured to drive a plurality of sensor electrodes for capacitive sensing, wherein each of the plurality of sensor electrodes comprises at least one common electrode of a plurality of common electrodes, the plurality of common electrodes configured to be driven for display updating and capacitive sensing during a display frame, wherein the display frame comprises a plurality of display line update periods, a first blanking period, a second blanking period and a third blanking period, wherein the first blanking period and the second blanking period occur before a last one of the plurality of display line update periods and the third blanking period occurs after the last one of the plurality of display line update periods and before a first display line update period of a second display frame and wherein a duration of the second blanking period is at least as long as one of the plurality of display line updates and is longer than the first blanking period.

2. The processing system of claim 1 , wherein the driver module, when driving the plurality of sensor electrodes for capacitive sensing, is configured to drive a first sensor electrode of the plurality of sensor electrodes during the second blanking period.

3. The processing system of claim 2 , wherein the driver module, when driving the first sensor electrode for capacitive sensing, is configured to drive the first sensor electrode for absolute capacitive sensing.

4. The processing system of claim 2 , wherein the driver module, when driving the plurality of sensor electrodes for capacitive sensing, is configured to drive the first sensor electrode with a transmitter signal, and wherein the processing system is configured to receive resulting signals with a second electrode of the plurality of sensor electrodes, wherein the resulting signals comprise effects corresponding to the transmitter signal.

5. The processing system of claim 1 , wherein the driver module is configured to receive a plurality of resulting signals when the plurality of sensor electrodes are driven for capacitive sensing, and wherein the processing system is further configured to determine positional information for an input object based on the resulting signals.

6. The processing system of claim 1 , wherein the third blanking period is longer than the first blanking period.

7. The processing system of claim 1 , wherein the second blanking period and the third blanking period differ in length.

8. The processing system of claim 1 , wherein the processing system is further configured to drive a second sensor electrode of the plurality of sensor electrodes for capacitive sensing during the second blanking period.

9. The processing system of claim 8 , wherein the first sensor electrode and the second sensor electrode are simultaneously driven with different ones of a plurality of transmitter signals.

10. An input device comprising:
a plurality of sensor electrodes, and
a processing system coupled to the plurality of sensor electrodes, the processing system configured to:
drive the plurality of sensor electrodes for capacitive sensing during a display frame of a display device to acquire a plurality of resulting signals, wherein the display frame comprises a first blanking period, a second blanking period and a third blanking period, wherein the first blanking period and the second blanking period occur before a last display line update period of the display frame and the third blanking period occurs after the last display line update period of the display frame, wherein a duration of the second blanking period is at least as long the last display line update and is longer than the first blanking period; and
determine positional information for an input object based on the resulting signals.

11. The input device of claim 10 , wherein the display device comprises a plurality of common electrodes configured for updating a display of the display device and for capacitive sensing, and wherein a first sensor electrode of the plurality of sensor electrodes comprises at least one of the plurality of common electrodes.

12. The input device of claim 11 , wherein the processing system, when driving the plurality of sensor electrodes for capacitive sensing, is further configured to drive the first sensor electrode for capacitive sensing during the second blanking period.

13. The input device of claim 12 , wherein the processing system, when driving the first sensor electrode for capacitive sensing, is further configured to drive the first sensor electrode for absolute capacitive sensing.

14. The input device of claim 12 , wherein the processing system, when driving the plurality of sensor electrodes for capacitive sensing, is further configured to drive the first sensor electrode with a transmitter signal, and wherein when receiving the resulting signals, the processing system is further configured to receive the resulting signals with a second sensor electrode of the plurality of sensor electrodes, wherein the resulting signals comprise effects corresponding to the transmitter signal.

15. The input device of claim 11 , wherein the plurality of sensor electrodes are disposed as an array of rectangles.

16. A method of capacitive sensing, the method comprising:
driving a plurality of sensor electrodes for capacitive sensing during a display frame of a display device to acquire a plurality of resulting signals, wherein the display frame comprises a first blanking period set, a second blanking period set and a third blanking period set, wherein the first blanking period set has a greater number of blanking periods than that of the second blanking period set, wherein the second blanking period set has a greater number of blanking periods than that of the third blanking period set, wherein each blanking period of the second blanking period set is longer than each blanking period of the first blanking period set, and wherein driving the plurality of sensor electrodes for capacitive sensing during the display frame comprises driving a first sensor electrode for capacitive sensing during a first blanking period of the second blanking period set; and
determining positional information for an input object based on the plurality of resulting signals.

17. The method of claim 16 , wherein each blanking period of the second blanking period set differs in length than each blanking period of the third blanking period set.

18. The method of claim 16 , wherein driving the first sensor electrode for capacitive sensing comprises driving the first sensor electrode for absolute capacitive sensing.

19. The method of claim 16 , wherein driving the plurality of sensor electrodes for capacitive sensing comprises driving the first sensor electrode with a transmitter signal and wherein receiving the resulting signals comprises receiving the resulting signals with a second sensor electrode of the plurality of sensor electrodes, wherein the resulting signals comprise effects corresponding to the transmitter signal.

Assignees

• Synaptics Inc

Inventors

• Shepelev Petr
• Schwartz Adam L

Classifications

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/044

  by capacitive means · CPC title

• 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

• G06F3/04184

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