Orthogonal Multi-Row Touch Panel Stimulation

• US 20150091869A1
• Filed: 12/10/2014
• Published: 04/02/2015
• Est. Priority Date: 01/09/2012
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Sobel, David A., Ranganathan, Sumant, Walley, John S.
• Application Number:
  US14/565,753
• Publication Number:
  US 20150091869A1
• 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 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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

Control circuitry for a touch panel includes a touch panel interface, a memory comprising scanning logic, and a controller in communication with the memory and the touch panel interface. The controller is operable, when the scanning logic is executed, to energize a first and a second row in the touch panel simultaneously, a first time; obtain a first signal measurement along a column intersecting the first and second rows; energize the first and the second row in the touch panel simultaneously, a second time; obtain a second signal measurement along the column; and determine a first pixel value and a second pixel value along the column from the first signal measurement and the second signal measurement.

Claims

1. A method comprising:

performing a first measurement at a receiver when a transmitter energizes a region of a touch panel using a first waveform;

performing a second measurement at the receiver when the transmitter energizes the same region of the touch panel using a second waveform, the second waveform orthogonal in content to the first waveform; and

combining the first and second measurements to determine a pixel result on the touch panel.

2. The method of claim 1, where:

the first waveform comprises a first Hadamard sequence; and

the second waveform comprises a second Hadamard sequence different from the first.

3. The method of claim 1, where the region comprises a selected number of rows of the touch panel.

4. The method of claim 1, where the receiver is coupled to a column of the touch panel.

5. The method of claim 1, where:

the region is defined in a scan map; and

the method further comprises accessing the scan map to determine the region.

6. The method of claim 1, where the first measurement and the second measurement are performed at different times.

7. The method of claim 1, where further comprising characterizing a touch blob on the touch panel responsive to the determined pixel result.

8. A device comprising:

a touch panel; and

touch panel circuitry comprising;

a transmitter configured to;

transmit a first waveform over a portion of the touch panel; and

transmit a second waveform over the same portion of the touch panel,

the second waveform orthogonal to the first waveform; and

a receiver configured to;

perform a first measurement when the transmitter transmits the first waveform over the portion of the touch panel; and

perform a second measurement when the transmitter transmits the second waveform over the portion of the touch panel; and

measurement circuitry configured to;

combine the first and second measurements to determine a combined measurement; and

responsive to the combined measurement, determine a pixel result on the touch panel.

9. The device of claim 8, further comprising memory configured to store a scan map, the portion of the touch panel and first waveform defined in the scan map;

and where the measurement circuitry is further configured to access the scan map to determine the portion of the touch panel and first waveform.

10. The device of claim 8, where the transmitter is coupled to a row of the touch panel.

11. The device of claim 8, where the receiver is coupled to a column of the touch panel.

12. The device of claim 8, where the transmitter is configured to transmit the first and second waveforms at different times.

13. The device of claim 8, where the measurement circuitry is further configured to cause the transmitter to transmit the first and second waveforms in response to a command to increase a signal-to-noise ratio for the touch panel.

14. The device of claim 8, where the first and second waveforms comprise Hadamard sequences.

15. The device of claim 8, wherein the measurement circuitry is further configured to characterize a touch blob using the pixel result.

16. A device comprising:

a touch panel;

a receiver coupled to the touch panel, the receiver configured to perform multiple measurements on the touch panel, the multiple measurements including measurements of waveforms that are orthogonal in content; and

measurement circuitry coupled to the receiver, the measurement circuitry is configured to, based on the orthogonal content of the waveforms, determine a pixel result for the touch panel using the multiple measurements.

17. The device of claim 16, where the measurement circuitry is further configured to determine multiple pixel results using the multiple measurements.

18. The device of claim 17, where the measurement circuitry is further configured to characterize a touch blob responsive to the multiple pixel results.

19. The device of claim 16, where the measurement circuitry is configured to cause the receiver to perform the multiple measurements in response to a command to increase signal-to-noise ratio.

20. The device of claim 16, where:

the measurement circuitry comprises memory configured to store a scan map; and

the waveforms that are orthogonal in content are defined in the scan map.