TIME SHARING OF DISPLAY AND SENSING DATA

• US 20160195988A1
• Filed: 01/04/2016
• Published: 07/07/2016
• Est. Priority Date: 01/05/2015
• Status: Active Application

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: FU, Chih-Hong, REYNOLDS, Joseph Kurth
• Granted Patent: US 10,275,070 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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

Abstract

This disclosure generally provides input devices, processing systems and methods for touch sensing that maintain substantially equal capacitive sensing frame reporting rates when operated at different display refresh rates.

Claims

1. An input device comprising:

a plurality of sensor electrodes;

a display device integrated with the plurality of sensor electrodes; and

a processing system operatively coupled to the plurality of sensor electrodes and to the display device, the processing system configured to;

operate in a first mode to update the display device at a first display refresh rate and drive the sensor electrodes for capacitive sensing at a first capacitive sensing frame rate during a first display frame, wherein the first capacitive sensing frame rate is greater than the first display refresh rate; and

operate in a second mode to update the display device at a second display refresh rate and drive the sensor electrodes for capacitive sensing at a second capacitive sensing frame rate during a second display frame, wherein the second capacitive sensing frame rate is greater than the second display refresh rate, wherein the first display refresh rate and the second display refresh rate differ by a first amount, wherein the first capacitive sensing frame rate and the second capacitive sensing frame rate differ by a second amount, wherein the second amount is less than the first amount.

2. The input device of claim 1, wherein the processing system, while in the second mode of operation, is further configured to:

drive at least one of the plurality of sensor electrodes for capacitive sensing during a long horizontal blanking period, wherein the long horizontal period comprises at least one synchronizing delay line/period.

3. The input device of claim 2, wherein the processing system, while in the second mode of operation, is further configured to:

drive a second source line with display data during a second display update interval, wherein the touch sensing interval is between the first display update interval and the second display update interval.

4. The input device of claim 2, wherein the processing system, while in the second mode of operation, is further configured to:

drive at least one of the plurality of sensor electrodes during the non-display update period between portions of a single display update frame.

5. The input device of claim 2, wherein the processing system, during the second display update period and while in the second mode of operation, is further configured to:

insert the synchronizing delay after driving all of the source lines with display data.

6. The input device of claim 2, wherein the processing system, during the display update period and while in the second mode of operation, is further configured to:

insert the synchronizing delay prior to driving a second source line with display data within a single display update cycle.

7. The input device of claim 1, wherein the processing system, while in the second mode of operation, is further configured to:

drive a source line with line refresh data in response to a complete set of line refresh data being available in a buffer; and

insert a synchronization delay in response to a complete set of line refresh data not being available in the buffer.

8. The input device of claim 1, wherein the processing system, during the display update period and while in the second mode of operation, is further configured to:

drive a first source line with display data during a first display update interval;

drive a second source line with display data during a second display update interval;

drive the second source line with synchronization delay, wherein a length of time that the second source line is driven with synchronization delay is selected to maintain the capacitive sensing frame report rate substantially constant during the first and second modes of operation; and

drive at least one of the plurality of sensor electrodes during the non-display update period after the second display update interval and between portions of a single display update frame.

9. The input device of claim 1, wherein the processing system is further configured to:

drive the plurality of sensor electrodes during display update periods to refresh the display device and during non-display update periods for capacitive sensing.

10. The input device of claim 1, wherein the display device comprises:

a plurality of source drivers configured to drive the sensor electrodes for capacitive sensing; and

a touch controller coupled to each source driver through a single wire, the touch controller configured to communicate display and touch data through the wire.

11. The input device of claim 1, wherein the plurality of sensor electrodes are arranged in a matrix array.

12. The input device of claim 1, wherein, the processing system, while operating in the first mode, is further configured to drive the sensor electrodes for capacitive sensing during long horizontal blanking periods.

13. The input device of claim 1, wherein the second amount is fraction of the first amount.

14. The input device of claim 1, wherein the second amount is approximately zero.

18. The processing system of claim 13, wherein the sensor circuitry, while in the second mode of operation, is further configured to:

drive at least one of the plurality of sensor electrodes during the non-display update period between portions of a single display update frame.

19. The processing system of claim 13, wherein the sensor circuitry, while in the second mode of operation, is further configured to:

drive a source line with the line refresh data in response to a complete set of line refresh data being available in a buffer; and

insert a synchronization delay in response to a complete set of line refresh data being not available in the buffer.

20. The processing system of claim 18, wherein the sensor circuitry, during the second display update period and while in the second mode of operation, is further configured to:

drive a first source line with display data during a first display update interval;

drive a second source line with display data during a second display update interval;

drive the second source line with synchronization delay, wherein a length of the synchronization delay is selected to maintain the capacitive sensing frame report rate substantially constant during the first and second modes of operation; and

drive at least one of the plurality of sensor electrodes during the non-display update period after the second display update interval and between portions of a single display update frame.

21. The processing system of claim 13, wherein the sensor circuitry, during the second display update period and while in the second mode of operation, is further configured to:

insert the synchronizing delay prior to driving a second source line with display data within a single display update cycle.

22. The processing system of claim 13, wherein the sensor circuitry, during the second display update period and while in the second mode of operation, is further configured to:

insert the synchronizing delay after driving all of the source lines with display data.

23. The processing system of claim 18, wherein the sensor circuitry is further configured to:

drive the plurality of sensor electrodes during display update periods to refresh the display device and during non-display update periods for capacitive sensing.

24. The processing system of claim 18, wherein the sensor circuitry further comprises:

a plurality of source drivers configured to drive the sensor electrodes for capacitive sensing; and

a touch controller coupled to each source driver through a single wire, the touch controller configured to communicate display and touch data through the wire.

25. The processing system of claim 13, wherein the sensor circuitry, during synchronizing delay, is further configured to:

does not update the display device.

26. The processing system of claim 13, wherein the sensor circuitry, during synchronizing delay, is further configured to:

update the display device with display data from a buffer previously driven onto the sensor electrodes.

15. Processing system comprising:

a sensor module configured to operate a plurality of sensor electrodes during a non-display update period for capacitive sensing, the sensor module having sensor circuitry configured to;

in a first mode of operation, update the display device at a first display refresh rate with a first capacitive sensing frame report rate during a first display update period; and

in a second mode of operation, update the display device at a second display refresh rate with a second capacitive sensing frame report rate during a second display update period, wherein the first display refresh rate and the second display refresh rate are different and wherein the first capacitive sensing frame report rate and the second capacitive sensing frame report rate are about equal for at least half of the first and second display update periods.

16. The processing system of claim 15, wherein the sensor circuitry, while in the second mode of operation, is further configured to:

drive a first source line with display data during a first display update interval;

drive at least one of the plurality of sensor electrodes during a touch sensing interval; and

insert a synchronizing delay between the first display update interval and the touch sensing interval, a length of the synchronizing delay selected to maintain capacitive sensing frame report rate substantially constant relative to the capacitive sensing frame report rate of the first mode of operation.

17. The processing system of claim 16, wherein the sensor circuitry, while in the second mode of operation, is further configured to:

drive a second source line with display data during a second display update interval, wherein the touch sensing interval is between the first display update interval and the second display update interval.

27. A method for operating an input device, the method comprising:

operating a plurality of sensor electrodes during a non-display update period for capacitive sensing;

in a first mode of operation, updating a display device at a first display refresh rate with a first capacitive sensing frame report rate during a first display update period; and

in a second mode of operation, updating the display device at a second display refresh rate with a second capacitive sensing frame report rate during a second display update period, wherein the first display refresh rate and the second display refresh rate are different and wherein the first capacitive sensing frame report rate and the second capacitive sensing frame report rate are about equal for at least half of the first and second display update periods.

28. The method of claim 27 further comprising:

driving a first source line with display data during a first display update interval;

driving at least one of the plurality of sensor electrodes during a touch sensing interval; and

inserting a synchronizing delay between the first display update interval and the touch sensing interval, a length of the synchronizing delay selected to maintain capacitive sensing frame report rate substantially constant relative to the capacitive sensing frame report rate of the first mode of operation.