ASYMMETRIC MULTI-ROW TOUCH PANEL SCANNING

• US 20130176274A1
• Filed: 03/09/2012
• Published: 07/11/2013
• 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., Chang, Pi Sheng, Weaver, Glen, de Roche, Kerrynn Jacques
• Granted Patent: US 9,001,072 B2
• Time in Patent Office: Days
• 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;

determining orthogonal signals for driving the touch panel; and

asymmetrically scanning the touch panel using the orthogonal signals 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, where the scan map represents:

a first sub-panel of the touch panel and a second sub-panel of the touch panel, where the first and second sub-panels are distinguished by number of step scans applied to the first and second sub-panels.

5. 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.

6. 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.

7. The method of claim 1, where the predetermined condition comprises an increase in signal to noise ratio above a predetermined threshold.

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

a touch panel interface;

a memory comprising scanning logic and a scan map; and

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

asymmetrically scan the touch panel in a region of interest through the touch panel interface according to the scan map.

9. The control circuitry of claim 8, where the scan map distinguishes the touch panel into:

a first sub-panel and a second sub-panel, according to a number of step scans used

in each sub-panel, and where the number of step scans differs to specify asymmetrically scanning the touch panel.

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 to increase signal to noise ratio in the region of interest.

11. 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.

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

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

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

15. A product comprising:

a machine readable medium; and

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

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

asymmetrically scan the touch panel in a region of interest according to the scan map and the asymmetric scanning parameters.

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 scan map represents:

a first sub-panel of the touch panel and a second sub-panel of the touch panel, where the first and second sub-panels are distinguished by number of step scans applied to the first and second sub-panels.

19. 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.

20. 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.