Orthogonal Multi-Row Touch Panel Stimulation

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.

What is claimed is: 
     
         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.