Scanning a single-layer capacitive sense array

• US 9,542,042 B2
• Filed: 10/15/2014
• Issued: 01/10/2017
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Parade Technologies, Ltd.
• Inventors: Ksondzyk, Petro, Mandziy, Vasyl, Kolych, Igor, Badaye, Massoud
• Primary Examiner(s): He, Amy
• Application Number:
  US14/514,654
• Publication Number:
  US 20150062093A1
• Time in Patent Office: 818 Days
• Field of Search: 324/601, 324/663, 324/687, 345/173, 345/174
• US Class Current: 1/1
• CPC Class Codes: G01N 27/22 by investigating capacitance
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality

Abstract

A method performs a scan operation for a single-layer sensor array that includes transmit (TX) electrodes and receive (RX) electrodes. The method includes determining whether to include a signal value for an RX electrode in a computation of a slope parameter value for a TX electrode. The method computes an index sum based on an index of the RX electrode when the signal value for the RX electrode is included in the computation of the slope parameter value for the TX electrode. The method computes a signal sum based on the signal value for the RX electrode when the signal value for the RX electrode is included in the computation of the slope parameter value for the TX electrode. The method then computes the slope parameter value for the TX electrode based on the signal sum and the index sum.

Claims

1. A method of performing a scan operation for a single-layer sensor array comprising transmit (TX) electrodes and receive (RX) electrodes, the method comprising a set of operations, including:

(a) determining, by a processing device, whether to include a signal value for an RX electrode in a computation of a slope parameter value for a TX electrode;

(b) computing, by the processing device, an index sum based on an index of the RX electrode when the signal value for the RX electrode is included in the computation of the slope parameter value for the TX electrode;

(c) computing, by the processing device, a signal sum based on the signal value for the RX electrode when the signal value for the RX electrode is included in the computation of the slope parameter value for the TX electrode; and

(d) computing, by the processing device, the slope parameter value for the TX electrode based on the signal sum and the index sum.

2. The method of claim 1, further comprising, prior to performing operation (d), repeating operations (a), (b), and (c) for each RX electrode that is interleaved with the TX electrode in the sensor array.

3. The method of claim 1, wherein operation (a) comprises comparing the signal value for the RX electrode to a tail-effect threshold.

4. The method of claim 3, wherein operation (a) further comprises determining to include the signal value for the RX electrode in the computation of the slope parameter value for the TX electrode when the signal value is greater than zero and less than the tail-effect threshold.

5. The method of claim 1, wherein the set of operations further includes:

(e) using, by the processing device, the slope parameter value to determine an adjustment value corresponding to tail effect for a sensor element, in the sensor array, that is formed by the TX electrode and the RX electrode.

6. The method of claim 5, wherein operation (e) comprises computing the adjustment value for the sensor element by multiplying the slope parameter value and the index of the RX electrode.

7. The method of claim 5, further comprising repeating operation (e) for RX electrodes that form sensor elements with the TX electrode.

8. The method of claim 5, wherein the set of operations further includes:

(f) computing, by the processing device, a corrected signal value for the sensor element based on the adjustment value and the signal value for the RX electrode.

9. The method of claim 8, further comprising repeating operation (f) for RX electrodes that form sensor elements with the TX electrode.

10. The method of claim 8, wherein the set of operations further includes:

(g) calculating, by the processing device, a location position of a conductive object on the sensor array based at least on the corrected signal value for the sensor element.

11. A non-transitory computer-readable medium storing a set of instructions for performing a scan operation for a single-layer sensor array comprising transmit (TX) electrodes and receive (RX) electrodes, the set of instructions including instructions which, when executed by a processing device, cause the processing device to perform operations comprising:

(a) determining whether to include a signal value for an RX electrode in a computation

of a slope parameter value for a TX electrode;

(b) computing an index sum based on an index of the RX electrode when the signal value for the RX electrode is included in the computation of the slope parameter value for the TX electrode;

(c) computing a signal sum based on the signal value for the RX electrode when the signal value for the RX electrode is included in the computation of the slope parameter value for the TX electrode; and

(d) computing the slope parameter value for the TX electrode based on the signal sum and the index sum.

12. The non-transitory computer-readable medium of claim 11, wherein the set of instructions further comprises instructions which, when executed by the processing device, cause the processing device, prior to performing operation (d), to repeat operations (a), (b), and (c) for each RX electrode that is interleaved with the TX electrode in the sensor array.

13. The non-transitory computer-readable medium of claim 11, wherein the instructions that cause operation (a) comprise instructions which, when executed by the processing device, cause the processing device to compare the signal value for the RX electrode to a tail-effect threshold.

14. The non-transitory computer-readable medium of claim 13, wherein the instructions that cause operation (a) further comprise instructions which, when executed by the processing device, cause the processing device to determine to include the signal value for the RX electrode in the computation of the slope parameter value for the TX electrode when the signal value is greater than zero and less than the tail-effect threshold.

15. The non-transitory computer-readable medium of claim 11, wherein the set of instructions further comprises instructions which, when executed by the processing device, cause the processing device to perform an operation of:

(e) using the slope parameter value to determine an adjustment value corresponding to tail effect for a sensor element, in the sensor array, that is formed by the TX electrode and the RX electrode.

16. The non-transitory computer-readable medium of claim 15, wherein the instructions that cause operation (e) comprise instructions which, when executed by the processing device, cause the processing device to compute the adjustment value for the sensor element by multiplying the slope parameter value to the index of the RX electrode.

17. The non-transitory computer-readable medium of claim 15, wherein the set of instructions further comprises instructions which, when executed by the processing device, cause the processing device to repeat operation (e) for RX electrodes that form sensor elements with the TX electrode.

18. The non-transitory computer-readable medium of claim 15, wherein the set of instructions further comprises instructions which, when executed by the processing device, cause the processing device to perform an operation of:

(f) computing a corrected signal value for the sensor element based on the adjustment value and the signal value for the RX electrode.

19. The non-transitory computer-readable medium of claim 18, wherein the set of instructions further comprises instructions which, when executed by the processing device, cause the processing device to repeat operation (f) for RX electrodes that form sensor elements with the TX electrode.

20. The non-transitory computer-readable medium of claim 18, wherein the set of instructions further comprises instructions which, when executed by the processing device, cause the processing device to perform an operation of:

(g) calculating a location position of a conductive object on the sensor array based at least on the corrected signal value for the sensor element.