Active stylus differential synchronization
First Claim
1. A touch sensing system, comprising:
- a display device including a touch sensor having a matrix of row electrodes and column electrodes;
drive logic coupled to the row electrodes and configured to drive the row electrodes during a plurality of touch-sensing frames, each of which includes a stylus sync sub-frame during which the drive logic drives at least some of the row electrodes, referred to for that stylus sync sub-frame as sync-driven row electrodes, with synchronization waveforms that are communicated electrostatically to cause synchronization of the display device with an active stylus; and
where for each of the stylus sync sub-frames, the drive logic is configured to differentially drive the sync-driven row electrodes of such stylus sync sub-frame, such that a first synchronization waveform used to drive one of the sync-driven row electrodes is different than a second synchronization waveform used to drive another of the sync-driven row electrodes.
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Accused Products
Abstract
A touch-sensing system is disclosed. The system includes a display device having a touch sensor with a matrix of row electrodes and column electrodes. Drive logic drives the row electrodes in a plurality of stylus sync sub-frames. In each, some row electrodes, referred to for that stylus sync sub-frame as sync-driven row electrodes, are driven by the drive logic with synchronization waveforms to synchronize the display device with an active stylus. For each stylus sync sub-frame, the sync-driven row electrodes are differentially driven by the drive logic, in the sense that a synchronization waveform used to drive one of the sync-driven row electrodes is different than a synchronization waveform used to drive another of the sync-driven row electrodes.
16 Citations
20 Claims
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1. A touch sensing system, comprising:
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a display device including a touch sensor having a matrix of row electrodes and column electrodes; drive logic coupled to the row electrodes and configured to drive the row electrodes during a plurality of touch-sensing frames, each of which includes a stylus sync sub-frame during which the drive logic drives at least some of the row electrodes, referred to for that stylus sync sub-frame as sync-driven row electrodes, with synchronization waveforms that are communicated electrostatically to cause synchronization of the display device with an active stylus; and where for each of the stylus sync sub-frames, the drive logic is configured to differentially drive the sync-driven row electrodes of such stylus sync sub-frame, such that a first synchronization waveform used to drive one of the sync-driven row electrodes is different than a second synchronization waveform used to drive another of the sync-driven row electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A touch-sensing method for a display device having a touch sensor with a matrix of row electrodes and column electrodes, comprising:
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driving the row electrodes during a plurality of touch-sensing frames, each of which includes a stylus sync sub-frame; and during each stylus sync sub-frame, driving at least some of the row electrodes, referred to for that stylus sync sub-frame as sync-driven row electrodes, with synchronization waveforms configured to be electrostatically communicated to an active stylus to synchronize the display device and the active stylus, where such driving during each stylus sync sub-frame includes differentially driving the sync-driven row electrodes of that stylus sync sub-frame, such that a first synchronization waveform used to drive one of the sync-driven row electrodes is different than a second synchronization waveform used to drive another of the sync-driven row electrodes. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A touch-sensing system, comprising:
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a display device including a touch sensor having a matrix of row electrodes and column electrodes; drive logic coupled to the row electrodes; where the drive logic is configured to drive the row electrodes during a plurality of touch-sensing frames, each of which includes a stylus sync sub-frame during which the drive logic drives at least some of the row electrodes, referred to for that stylus sync sub-frame as sync-driven row electrodes, with synchronization waveforms to facilitate synchronization of the display device with an active stylus; where the drive logic is configured, for any given one of the stylus sync sub-frames, to select from among a plurality of sets of sync-driven row electrodes and differentially drive sync-driven row electrodes in that set of sync-driven row electrodes during the stylus sync sub-frame; where the sets of sync-driven row electrodes differ from one another in terms of which of the row electrodes are sync-driven row electrodes; and where for each of the sets of sync-driven row electrodes, the differential driving includes, for each a plurality of spatial groupings of sync-driven row electrodes in the set, using two or more different synchronization waveforms in the spatial grouping which are configured to produce at least partially cancelling electrical conditions to reduce, in the event of a user'"'"'s body part touching the display device on a contact patch over the spatial grouping, current flowing into the user'"'"'s body part, relative to current which would flow in the case of undifferentiated driving of the sync-driven row electrodes in the spatial grouping. - View Dependent Claims (18, 19, 20)
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Specification