Asymmetric multi-row touch panel scanning

• US 9,001,072 B2
• Filed: 03/09/2012
• Issued: 04/07/2015
• Est. Priority Date: 01/09/2012
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Sobel, David A., Ranganathan, Sumant, Li, Tianhao, Walley, John S., Weaver, Glen, de Roche, Kerrynn Jacques, Chang, Pi Sheng
• Primary Examiner(s): Bibbins, Latanya
• Application Number:
  US13/416,327
• Publication Number:
  US 20130176274A1
• Time in Patent Office: 1,124 Days
• Field of Search: 345/174
• US Class Current: 345/174
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

Asymmetric scanning logic implements asymmetric panel scanning by scanning some rows on a touch panel more frequently than other rows. Note that although an entire row at a time may be driven, if only particular pixels in the row are of interest (e.g., included in any region of interest for focused asymmetric scanning), then circuitry may power down the receivers for the columns in which the pixels exist to save power. The asymmetric scanning logic facilitates focused attention to specific areas of interest on the touch panel, to compensate, for example, for high noise or low signal strength in those areas of interest.

Claims

1. A method for scanning a touch panel, the method comprising:

retrieving asymmetric scanning parameters and a scan map for a touch panel;

responsive to the scan map determining a first step scan and a second step scan;

determining a first orthogonal signal for driving the touch panel during the first step scan;

determining a second orthogonal signal for driving the touch panel during the second step scan, the first orthogonal signal orthogonal in content to the second orthogonal signal; and

asymmetrically scanning the touch panel using the first and second orthogonal signals and the first and second step scans according to the scan map and the asymmetric scanning parameters.

2. The method of claim 1, further comprising:

receiving an identification of a region of interest on the touch panel; and

where asymmetrically scanning the touch panel comprises;

asymmetrically scanning the touch panel in the region of interest.

3. The method of claim 2, where receiving an identification comprises:

receiving an identification of a region of interest where additional signal to noise ratio (SNR) is desired.

4. The method of claim 1, further comprising:

receiving an identification of a relatively low signal-to-noise ratio region on the touch panel;

reading from the scan map a number of step scans for the relatively low signal-to-noise ratio region; and

where asymmetrically scanning the touch panel comprises;

asymmetrically scanning the relatively low signal-to-noise ratio region using the number of step scans.

5. The method of claim 1, further comprising:

determining a predicted location of a blob on the touch panel; and

configuring the scan map to asymmetrically scan the predicted location.

6. The method of claim 1, further comprising distinguishing a first sub-panel of the touch panel responsive to the first and second step scans.

7. The method of claim 6, wherein the first and second step scans are performed on the first sub-panel;

and

a third step scan is performed on a second sub-panel different from the first sub-panel.

8. Control circuitry for a touch panel, the control circuitry comprising:

a touch panel interface;

a memory comprising scanning logic and a scan map, the scan map specifying a first step scan and a second step scan; and

a controller in communication with the memory and the touch panel interface, the controller operable, when the scanning logic is executed, to;

determine a first orthogonal waveform for the first step scan;

determine a second orthogonal waveform for the second step scan, the second orthogonal waveform orthogonal in content to the first orthogonal waveform; and

asymmetrically scan the touch panel in a region of interest through the touch panel interface according to the scan map, the asymmetric scan including the first and second step scans.

9. The control circuitry of claim 8, where the controller is further operable to:

initiate asymmetrically scanning the region of interest in response to a request to increase signal to noise ratio in the region of interest.

10. The control circuitry of claim 8, where the controller is further operable to:

initiate asymmetrically scanning the region of interest in response to a request that specifies that activity is occurring in the region of interest.

11. The control circuitry of claim 8, where the region of interest comprises a predicted blob location.

12. The control circuitry of claim 8, where the region of interest comprises a predicted blob location and a buffer row.

13. The control circuitry of claim 8, where the region of interest comprises a predicted blob location a buffer column.

14. The control circuitry of claim 8, wherein the scan map distinguishes a sub-panel of the touch panel based on the first and second step scans.

15. A product comprising:

a non-transitory machine readable medium; and

instructions stored on the medium that when executed by a system, cause the system to;

retrieve a scan map for a touch panel, the scan map defining a first step scan and a second step scan;

determine a first orthogonal signal to drive the touch panel during the first step scan;

determine a second orthogonal signal to drive the touch panel during the second step scan, the first orthogonal signal orthogonal in content to the second orthogonal signal; and

asymmetrically scan the touch panel in a region of interest according to the first and second step scans and the first and second orthogonal signals.

16. The product of claim 15, where the instructions further cause the system to:

receive an identification of a region of interest on the touch panel; and

asymmetrically scan the touch panel in the region of interest.

17. The product of claim 15, where the instructions further cause the system to:

receive an identification of a region of interest where additional signal to noise ratio (SNR) is desired.

18. The product of claim 15, where the instructions further cause the system to:

receive an identification of a relatively low signal-to-noise ratio region on the touch panel;

read from the scan map a number of step scans for the relatively low signal-to-noise ratio region; and

asymmetrically scan the relatively low signal-to-noise ratio region as the region of interest using the number of step scans.

19. The product of claim 15, where the instructions further cause the system to:

determine a predicted location of a blob on the touch panel; and

configure the scan map to asymmetrically scan the predicted location.

20. The product of claim 15, wherein the instructions are further configured to:

scan a particular row during the first step scan; and

scan that particular row during the second step scan.