Capacitive sensor device

• US 8,896,328 B2
• Filed: 01/16/2014
• Issued: 11/25/2014
• Est. Priority Date: 05/13/2009
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Reynolds, Joseph Kurth, Acker, Phillip
• Primary Examiner(s): Vazquez, Arleen M
• Assistant Examiner(s): Andrews, Brent J
• Application Number:
  US14/156,906
• Publication Number:
  US 20140132287A1
• Time in Patent Office: 313 Days
• Field of Search: 324650-690, 345173-176, 702/65
• US Class Current: 324/686
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• 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 3/041662 using alternate mutual and self-capacitive scanning
• 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
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/960725 Charge-transfer
• CPC Class Codes: H03K 2217/96073 Amplitude comparison
• CPC Class Codes: H03K 2217/960765 Details of shielding arrangements
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion

Abstract

A processing system for a capacitive sensor device comprises circuitry and logic; and the capacitive sensor device comprises a first plurality of sensor electrodes and a second plurality of sensor electrodes. The processing system is configured to acquire a first plurality of capacitive measurements by emitting and receiving first electrical signals with the first plurality of sensor electrodes of the capacitive sensor device. The processing system is also configured to select a first set of the first plurality of sensor electrodes based on the first plurality of capacitive measurements. The processing system is further configured to acquire a second plurality of capacitive measurements by emitting second electrical signals with the first set of the first plurality of sensor electrodes and receiving the second electrical signals with the second plurality of sensor electrodes.

Claims

1. A processing system for a capacitive sensor device comprising a first plurality of sensor electrodes and a second plurality of sensor electrodes, said processing comprising circuitry and logic configured to:

acquire a first plurality of capacitive measurements by emitting and receiving first electrical signals with said first plurality of sensor electrodes of said capacitive sensor device, wherein the first plurality of capacitive measurements are absolute capacitive measurements,

select a first set of said first plurality of sensor electrodes based on said first plurality of capacitive measurements, and

acquire a second plurality of capacitive measurements by emitting second electrical signals with said first set of said first plurality of sensor electrodes and receiving said second electrical signals with said second plurality of sensor electrodes, wherein the second plurality of capacitive measurements are transcapacitive measurements.

2. The processing system of claim 1, further configured to determine positional information of at least one input object in a sensing region of said capacitive sensor device based on at least one of said first plurality of capacitive measurements and said second plurality of capacitive measurements.

3. The processing system of claim 1, further configured to make a first estimate of a position of at least one input object using said first plurality of capacitive measurements and to make a second estimate of said position of said at least one input object using said second plurality of capacitive measurements, wherein said second estimate is of finer resolution than said first estimate.

4. The processing system of claim 1, further configured to make a first estimate of a position of at least one input object using said first plurality of capacitive measurements and to make a second estimate of said position of said at least one input object using said second plurality of capacitive measurements, wherein said making said first estimate comprises identifying possible locations of said at least one input object, and wherein said making a second estimate comprises disambiguating said possible locations.

5. The processing system of claim 1, further configured to:

determine a first position estimate of an input object using said first plurality of capacitive measurements, said first position estimate locating said input object relatively farther an input surface said capacitive sensor device, and

determine a second position estimate of said input object using said second plurality of capacitive measurements, said second position estimate locating said input object relatively closer to said input surface.

6. The processing system of claim 1, further configured to:

determine at least one of a size, type, and a capacitive coupling to system ground of an input object using said first and second pluralities of capacitive measurements.

7. The processing system of claim 1, further configured to enter a sleep based on a determination that no input objects are in a sensing region of the capacitive sensor device, said determination based on said first plurality of capacitive measurements.

8. The processing system of claim 1, further configured to acquire a third plurality of capacitive measurements by emitting and receiving third electrical signals with said second plurality of sensor electrodes of said capacitive sensor device, and select a first set of said second plurality of sensor electrodes based on said third plurality of capacitive measurements.

22. The processing system of claim 1, further configured to produce a partial image based on the second plurality of capacitive measurements.

9. A method of sensing using a capacitive sensor device comprising a first plurality of sensor electrodes and a second plurality of sensor electrodes, said method comprising:

acquiring a first plurality of capacitive measurements by emitting and receiving first electrical signals with said first plurality of sensor electrodes, wherein the first plurality of capacitive measurements are absolute capacitive measurements,

selecting a first set of said first plurality of sensor electrodes based on said first plurality of capacitive measurements, and

acquiring a second plurality of capacitive measurements by emitting second electrical signals with said first set of said first plurality of sensor electrodes and receiving said second electrical signals with said second plurality of sensor electrodes, wherein the second plurality of capacitive measurements are transcapacitive measurements.

10. The method of claim 9, further comprising:

determining positional information of at least one input object in a sensing region of said capacitive sensor device based on at least one of said first plurality of capacitive measurements and said second plurality of capacitive measurements.

11. The method of claim 9, further comprising:

making a first estimate of a position of at least one input object using said first plurality of capacitive measurements and making a second estimate of said position of said at least one input object using said second plurality of capacitive measurements, wherein said second estimate is of finer resolution than said first estimate.

12. The method of claim 9, further comprising:

determining a first position estimate of an input object using said first plurality of capacitive measurements, said first position estimate locating said input object relatively farther an input surface said capacitive sensor device, and

determining a second position estimate of said input object using said second plurality of capacitive measurements, said second position estimate locating said input object relatively closer to said input surface.

13. The method of claim 9, further comprising:

acquiring a third plurality of capacitive measurements by emitting and receiving third electrical signals with said second plurality of sensor electrodes of said capacitive sensor device, and select a first set of said second plurality of sensor electrodes based on said third plurality of capacitive measurements.

23. The method of claim 9, further comprising producing a partial image based on the second plurality of capacitive measurements.

14. A capacitive sensor device comprising:

a first plurality of sensor electrodes;

a second plurality of sensor electrodes; and

a processing system coupled to said first plurality of sensor electrodes and said second plurality of sensor electrodes, said processing system configured to;

acquire a first plurality of capacitive measurements by emitting and receiving first electrical signals with said first plurality of sensor electrodes, wherein the first plurality of capacitive measurements are absolute capacitive measurements,

make a first estimate of a position of at least one input object using said first plurality of capacitive measurements,

select a first set of said first plurality of sensor electrodes using said first estimate,

acquire a second plurality of capacitive measurements by emitting second electrical signals with said first set of said first plurality of sensor electrodes and receiving said second electrical signals with said second plurality of sensor electrodes, wherein the second plurality of capacitive measurements are transcapacitive measurements, and

make a second estimate of said position of said at least one input object using said second plurality of capacitive measurements.

15. The capacitive sensor device of claim 14, further comprising:

an input surface, wherein said processing system is further configured to;

determine a first position estimate of an input object using said first plurality of capacitive measurements, said first position estimate locating said input object relatively farther an input surface said capacitive sensor device, and

determine a second position estimate of said input object using said second plurality of capacitive measurements, said second position estimate locating said input object relatively closer to said input surface.

16. The capacitive sensor device of claim 14, wherein said at least one input object comprises two input objects.

17. The capacitive sensor device of claim 14, wherein said second estimate is of finer resolution than said first estimate.

18. The capacitive sensor device of claim 14, wherein said first estimate comprises:

possible locations of said at least one input object, and said second estimate is a disambiguation of said possible locations.

19. The capacitive sensor device of claim 14, wherein said processing system is further configured to:

determine at least one of a size, a type, and a capacitive coupling to system ground of an input object using said first and second pluralities of capacitive measurements.

20. The capacitive sensor device of claim 14, wherein said processing system is configured to:

acquire said first plurality of capacitive measurements during a first time period and to acquire said second plurality of capacitive measurements during a second time period different from said first time period; and

electrically guard said first plurality of sensor electrodes by modulating at least one sensor electrode of said second plurality of sensor electrodes with respect to a system ground during said first time period.

21. The capacitive sensor device of claim 14, wherein said first plurality of sensor electrodes are aligned a first axis and said second plurality of sensor electrodes are aligned a second axis non-parallel to said first axis, said second plurality of sensor electrodes forming a matrix pattern with said first plurality of sensor electrodes.

24. The capacitive sensor device of claim 14, wherein the processing system is further configured to produce a partial image based on the second plurality of capacitive measurements.