DETECTION WITH A CAPACITIVE BASED DIGITIZER SENSOR

• US 20150309616A1
• Filed: 11/27/2013
• Published: 10/29/2015
• Est. Priority Date: 11/27/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: N-Trig Ltd (Microsoft Corporation)
• Inventors: STERN, Yuval
• Granted Patent: US 11,340,731 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A method for capacitive based detection with a digitizer sensor including a plurality of conductive elements that are capacitively coupled is described. The method includes generating a drive signal including transient sections separated in time by flat sections, providing the drive signal generated to at least one conductive element of the digitizer sensor, and sampling outputs transferred to a second conductive element that is capacitively coupled to the at least one conductive element in response to providing the signal generated to the at least one conductive element. The sampling events of the sampling are timed to take place both in response to the transient sections of the drive signal and to the flat sections of the drive signal.

Claims

1. A method comprising:

generating a drive signal including transient sections separated in time by flat sections;

providing the drive signal to a first conductive element of a digitizer sensor;

associated with providing the drive signal, sampling outputs transferred to a second conductive element that is capacitively coupled to the first conductive element, wherein sampling events of the sampling are timed to take place based on the transient sections of the drive signal and to the flat sections of the drive signal; and

using a first output sampled associated with the flat sections to suppress noise a second output sampled associated with the transient sections.

3. The method according to claim 1, comprising subtracting amplitudes of the first outputs sampled in response to the flat sections from amplitudes of the second outputs sampled in response to the transient sections of the drive signal.

4. The method according to claim 3, wherein the subtracting is performed between pairs of contiguous outputs.

5. The method according to claim 1, comprising timing the sampling events occurring in response to the flat sections to occur after responses of the second conductive element to previous transient sections of the drive signal have faded.

6. The method according to claim 1, comprising timing the sampling events occurring in response to the flat sections to occur substantially at an onset of the transient sections of the drive signal.

7. The method according to claim 1, comprising timing the sampling events of the sampling to alternate between occurring in response to the transient sections of the drive signal and occurring in response to the flat sections of the drive signal.

8. The method according to claim 1, comprising timing the sampling events of the sampling to alternate between occurring twice in response to each of a plurality of the transient sections of the drive signal and occurring once in response to each of a plurality of the flat sections of the drive signal.

9. The method according to claim 1, wherein durations of the flat sections in the drive signal are defined to be irregular.

10. The method according to claim 1, wherein the drive signal is an oscillating signal that is periodically interrupted by a flat signal.

11. The method according to claim 10, wherein the oscillating signal is a sinusoidal signal with frequency lower than a frequency of occurrences of the flat sections.

12. The method according to claim 1, comprising:

generating a plurality of drive signals, wherein each drive signal includes transient sections separated in time by flat sections; and

applying time domain multiplexing for sampling the outputs in response to the plurality of drive signals on the second conductive element.

13. The method according to claim 12, wherein each of the plurality of drive signals includes an oscillating signal that is periodically interrupted by a flat signal.

14. The method according to claim 13, wherein a same oscillating frequency of the oscillating signal is used to generate each of the drive signals.

15. The method according to claim 13, wherein at least two drive signals have an oscillating signal with different oscillating frequency.

16. The method according to claim 1, wherein the digitizer sensor includes a first set of parallel conductive lines and second set of parallel conductive lines, the first and second set of conductive lines arranged in a grid pattern.

17. The method according to claim 16, wherein the first conductive element is a conductive line from the first set of parallel conductive lines and second conductive element is a conductive line from the second set of parallel conductive lines.

18. The method according to claim 17, comprising sampling output on all the conductive lines from the second set of parallel conductive lines in response to providing the drive signal.

2. (canceled)

19-25. -25. (canceled)

26. A system comprising:

a digitizer sensor including a first set of parallel conductive lines and second set of parallel conductive lines, the first and second set of conductive lines arranged in a grid pattern; and

a controller configured for;

providing a drive signal on a first conductive line of the first set of conductive lines, the drive signal including transient sections separated in time by flat sections;

sampling outputs transferred to a second conductive line that is capacitively coupled to the first conductive line in response to providing the drive signal to the first conductive line, wherein the sampling events of the sampling are timed to take place based on the transient sections of the drive signal and the flat sections of the drive signal; and

using a first output sampled associated with the flat sections to suppress noise in a second output sampled associated with the transient sections.

27. The system according to claim 26, wherein the controller is configured to subtract amplitude of the first output sampled in response to the flat sections from amplitude of the second output sampled in response to the transient sections of the drive signal.

28. The system according to claim 27, wherein subtracting the amplitude of the first output from amplitude of the second output is performed between pairs of contiguous outputs.

29. A device comprising:

a memory configured to store characterization of a drive signal; and

a circuit configured to;

provide the drive signal on a first conductive line of a first set of conductive lines of a digitizer sensor, the drive signal including transient sections separated in time by flat sections;

sample outputs transferred to a second conductive line of the digitizer sensor that is capacitively coupled to the first conductive line in response to providing the drive signal to the first conductive line, wherein the sampling events of the sampling are timed to take place based on the transient sections of the drive signal and the flat sections of the drive signal; and

use a first output sampled associated with the flat sections to suppress noise in a second output sampled associated with the transient sections.

30. The system according to claim 29, wherein the circuit is configured to subtract amplitude of the first output sampled in response to the flat sections from amplitude of the second output sampled in response to the transient sections of the drive signal.

31. The system according to claim 30, wherein subtracting the amplitude of the first output from amplitude of the second output is performed between pairs of contiguous outputs.