Multi-phase scanning
First Claim
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1. A method, comprising:
- during each scanning stage, of a plurality of scanning stages, applying a same drive signal to each of a plurality of transmitter electrodes of a touch panel simultaneously for at least a period of time;
changing phase relations of the same drive signal, applied to each of the plurality of transmitter electrodes, according to the plurality of scanning stages, wherein changing the phase relations comprises;
applying the same drive signal having a first phase to a first one of the plurality of transmitter electrodes during a first scanning stage of the plurality of scanning stages, wherein the same drive signal has the first phase as an in-phase drive signal;
during the first scanning stage, applying the same drive signal having a second phase to a second one of the plurality of transmitter electrodes, wherein the same drive signal has the second phase as an opposite phase drive signal;
selecting a pseudorandom sequence having a number of one and negative one values, wherein a number of values in the pseudorandom sequence is equal to a number of the plurality of transmitter electrodes, wherein the one values correspond to the in-phase drive signal and the negative one values correspond to the opposite phase drive signal;
applying either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the pseudorandom sequence;
rotating the pseudorandom sequence; and
applying either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the rotated pseudorandom sequence;
for each scanning stage, receiving sense signals from a plurality of receiver electrodes, wherein each sense signal represents capacitances of intersections of the plurality of transmitter electrodes and a respective one of the plurality of receiver electrodes; and
using the phase relations of the same drive signal and the plurality of sense signals to detect a presence of an object on the touch panel.
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Abstract
Apparatuses and methods of multi-phase scanning are described.
65 Citations
15 Claims
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1. A method, comprising:
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during each scanning stage, of a plurality of scanning stages, applying a same drive signal to each of a plurality of transmitter electrodes of a touch panel simultaneously for at least a period of time; changing phase relations of the same drive signal, applied to each of the plurality of transmitter electrodes, according to the plurality of scanning stages, wherein changing the phase relations comprises; applying the same drive signal having a first phase to a first one of the plurality of transmitter electrodes during a first scanning stage of the plurality of scanning stages, wherein the same drive signal has the first phase as an in-phase drive signal; during the first scanning stage, applying the same drive signal having a second phase to a second one of the plurality of transmitter electrodes, wherein the same drive signal has the second phase as an opposite phase drive signal; selecting a pseudorandom sequence having a number of one and negative one values, wherein a number of values in the pseudorandom sequence is equal to a number of the plurality of transmitter electrodes, wherein the one values correspond to the in-phase drive signal and the negative one values correspond to the opposite phase drive signal; applying either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the pseudorandom sequence; rotating the pseudorandom sequence; and applying either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the rotated pseudorandom sequence; for each scanning stage, receiving sense signals from a plurality of receiver electrodes, wherein each sense signal represents capacitances of intersections of the plurality of transmitter electrodes and a respective one of the plurality of receiver electrodes; and using the phase relations of the same drive signal and the plurality of sense signals to detect a presence of an object on the touch panel. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus comprising:
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phase circuitry configured to simultaneously apply a same drive signal, for at least a period of time, to each of a plurality of transmitter electrodes of a touch panel during a plurality of scanning stages, wherein; the plurality of scanning stages occur while the phase circuitry applies the same drive signal, the phase circuitry configured to provide phase modulation of the same drive signal applied to the plurality of transmitter electrodes according to the plurality of scanning stages; the phase circuitry is configured to drive a first phase of the same drive signal on a first one of the plurality of transmitter electrodes during a first scanning stage of the plurality of scanning stages, and during the first scanning stage, the phase circuitry is configured to drive a second phase of the same drive signal on a second one of the plurality of transmitter electrodes; the first phase of the same drive signal comprises an in-phase drive signal; the second phase of the same drive signal comprises an opposite phase drive signal; and the phase circuitry is configured to select a pseudorandom sequence having a number of one and negative one values, wherein a number of values in the pseudorandom sequence is equal to a number of the plurality of transmitter electrodes, wherein the one values correspond to the in-phase drive signal and the negative one values correspond to the opposite phase drive signal, the phase circuitry configured to applying either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the pseudorandom sequence, rotate the pseudorandom sequence, and apply either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the rotated pseudorandom sequence; and sensing circuitry configured to receive sense signals from a plurality of receiver electrodes, wherein each sense signal represents capacitances formed between the plurality of transmitter electrodes and a respective one of the plurality of receiver electrodes, responsive to the same drive signal and to detect a presence of an object on the touch panel. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A system comprising:
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a signal source configured to generate a carrier signal; phase circuitry configured to receive the carrier signal and then drive the carrier signal at different phases simultaneously for at least a period of time, on each of a plurality of transmitter electrodes of a touch panel according to a plurality of scanning stages, wherein the plurality of scanning stages occur while the phase circuitry drives the carrier signal; the phase circuitry is configured to drive a first phase of the same drive signal on a first one of the plurality of transmitter electrodes during a first scanning stage of the plurality of scanning stages, and during the first scanning stage, the phase circuitry is configured to drive a second phase of the same drive signal on a second one of the plurality of transmitter electrodes; the first phase of the same drive signal comprises an in-phase drive signal; the second phase of the same drive signal comprises an opposite phase drive signal; and the phase circuitry is configured to select a pseudorandom sequence having a number of one and negative one values, wherein a number of values in the pseudorandom sequence is equal to a number of the plurality of transmitter electrodes, wherein the one values correspond to the in-phase drive signal and the negative one values correspond to the opposite phase drive signal, the phase circuitry configured to applying either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the pseudorandom sequence, rotate the pseudorandom sequence, and apply either the in-phase drive signal or opposite phase drive signal to the plurality of transmitter electrodes according to the rotated pseudorandom sequence; and sensing circuitry configured to receive sense signals from a plurality of receiver electrodes, wherein each sense signal represents capacitances formed between the plurality of transmitter electrodes and a respective one of the plurality of receiver electrodes, responsive to carrier signal driven at the different phases and to detect a presence of an object on the touch panel. - View Dependent Claims (14, 15)
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Specification