Low power operation of an optical touch-sensitive device for detecting multitouch events
First Claim
1. A method for resolving touch events on a surface, the surface having emitters and detectors arranged around its periphery, the emitters producing optical beams received by the detectors, the touch events disturbing the optical beams, the method comprising:
- scanning for touch events using a lower power detection scheme that includes determining transmission coefficients for pairs of emitters and detectors;
determining whether a touch event is present when scanning using the lower power detection scheme;
computing, based on the transmission coefficients, a numerical measure of confidence in the determination of whether the touch event is present when scanning using the lower power detection scheme;
determining that the computed measure of confidence is lower than a specified confidence threshold;
responsive to the determination, scanning for the touch events using a higher power detection scheme; and
determining presence of one or more of the touch events based upon the higher power detection scheme scan.
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Accused Products
Abstract
An optical touch-sensitive device is able to determine the locations of multiple simultaneous touch events. The optical touch-sensitive device includes multiple emitters and detectors. Each emitter produces optical beams which are received by the detectors. Touch events disturb the optical beams. Detection schemes define the operation of the touch capability. Different detection schemes consume different amounts of power and may be used in combination to reduce overall power consumption.
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Citations
24 Claims
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1. A method for resolving touch events on a surface, the surface having emitters and detectors arranged around its periphery, the emitters producing optical beams received by the detectors, the touch events disturbing the optical beams, the method comprising:
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scanning for touch events using a lower power detection scheme that includes determining transmission coefficients for pairs of emitters and detectors; determining whether a touch event is present when scanning using the lower power detection scheme; computing, based on the transmission coefficients, a numerical measure of confidence in the determination of whether the touch event is present when scanning using the lower power detection scheme; determining that the computed measure of confidence is lower than a specified confidence threshold; responsive to the determination, scanning for the touch events using a higher power detection scheme; and determining presence of one or more of the touch events based upon the higher power detection scheme scan. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 24)
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15. A method for resolving touch events on a surface, the surface having emitters and detectors arranged around its periphery, the emitters producing optical beams received by the detectors, the touch events disturbing the optical beams, the method comprising:
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over a plurality of different scanning instances; scanning for events using a lower power detection scheme; for a subset of the instances; determining that the lower power detection scheme was inadequate to resolve the touch events, and scanning for the touch events using a higher power detection scheme, and determining touch events based upon the higher power detection scheme scan; and adjusting mechanisms of the lower power detection scheme based on feedback regarding a proportion of scans acquired using the higher power detection scheme during the different instances to determine the touch events. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. An optical touch-sensitive device capable of resolving touch events comprising:
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a surface on which touch events are to be detected; emitters and detectors arranged around a periphery of the surface, the emitters producing optical beams received by the detectors, the touch events disturbing the optical beam; and a touch event processor coupled, directly or indirectly, to the emitters and detectors, the touch event processor receiving information indicating which beams have been disturbed by touch events and configured to; control activation of the emitters and detectors to scan for touch events using a lower power detection scheme; resolve a first set of the touch events using the lower power detection scheme; determine that the lower power detection scheme was inadequate to determine a second set of the touch events with at least a required confidence; control activation of the emitters and detectors to scan for touch events using a higher power detection scheme; and attempt to resolve the second set of the touch events based upon the higher power detection scheme scan, wherein the higher power detection scheme is configured to consume sufficient power to resolve at least a threshold proportion of the second set of the touch events, and the lower power detection scheme is configured to consume sufficient power to minimize an average power to resolve touch events. - View Dependent Claims (23)
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Specification