Multiple electrode touch sensitive device
View Patent ↗Two different sets of electrodes in a touch sensitive device are formed to produce an electric field gradient from one end of the electrodes to the other end when opposite ends of the electrodes are driven with different voltages. A signal measuring cycle is performed by alternately driving the ends of one set of electrodes, while using the other set of electrodes to receive signals. The roles of the sets of electrodes are then reversed, such that the set that that was driven is now used to receive signals from the other set of electrodes. Reference signals may be obtained by driving both sides of one set of electrodes, and then both sides of the other set of electrodes. The signals obtained are then used to determine the touch position on the touch sensitive device.
1. A controller comprising:
a driver to provide signals to drive electrodes of a touch sensitive device, wherein the driver provides multiple sets of drive signals to at least four different drive lines to separately couple to both ends of two sets of electrodes having electric field gradients and wherein the sets of electrodes are arranged generally perpendicular to each other and to exchange signals;
a receiver to receive multiple sets of exchanged signals from both sets of electrodes responsive to the signals provided by the driver; and
wherein the driver provides drive signals in the form of bursts of pulses and the pulses are provided in at least six different sets bursts corresponding to at least six different measurements.
2. The controller of claim 1 and further comprising a processor in determine a touch position responsive to the exchanged signals received by the receiver.
3. The controller of claim 2 wherein exchanged signals received as a result of the drive signals being provided to both ends of the sets of electrodes are reference signals.
4. The controller of claim 1 wherein the exchanged signals are obtained from either end of the sets of electrodes.
5. The controller of claim 1 wherein the pulses are provided in six different sets of bursts corresponding to six different measurements.
6. The controller of claim 1 wherein four of the sets of bursts correspond to driving four different corresponding ends of the two sets of electrodes.
7. The controller of claim 6 wherein two of the sets of bursts correspond to driving both ends of each of the two sets of electrodes.
8. The controller of claim 1 wherein the controller is configured to selectively drive both sets of electrodes at the same time to operate in a proximity detection mode.
9. The controller of claim 1 wherein exchanged signals are obtained from sense circuitry coupled to one set of electrodes and sense circuitry coupled to a second set of electrodes.
10. The controller of claim 9 wherein each of the sense circuitry comprises a single sense capacitor corresponding to each set of electrodes.