Optical control system with modulated emitters
First Claim
1. An optical touch detection system comprising:
- a touch sensitive area within which touch events are to be detected;
a plurality of emitters and a plurality detectors arranged around a periphery of the touch sensitive area, each emitter producing a plurality of optical beams received by a plurality of the detectors, wherein touch events disturb the optical beams; and
an optical control system coupled to the emitters and detectors, the optical control system configured to;
control activation of a plurality of the emitters and detectors simultaneously according to a modulation scheme comprising a plurality of different functions, each function alternating an associated one of the emitters between an activated state and a deactivated at a pattern of times varying from that of each other function in the modulation scheme,wherein in the activated state the associated emitter is emitting optical beams and in the deactivated state the associated emitter is not emitting optical beams such that the deactivated state consumes less power than the activated state; and
correlate output from the detectors regarding which optical beams have been disturbed by a touch event with the different functions to determine a location within the touch sensitive area where the touch event occurred.
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Accused Products
Abstract
An optical control system is described, which employs a series of optical emitters and detectors arranged about a touch area. The emitters are driven by a series of functions, and the system is operable to correlate the signals received at the detectors with the functions to determine the amount of energy received by the detectors from each of the emitters. This system means that all or many emitters can be modulated simultaneously, so the scanning process is accelerated. Also, the energy estimates arrived at by correlation with the functions are largely unaffected by external interference signals as well by each other. An additional benefit of the present invention is that the correlation processing makes use of many detector samples and tends to yield results which have higher resolution than the sample values themselves, due to the averaging of noise over the sample set.
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Citations
20 Claims
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1. An optical touch detection system comprising:
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a touch sensitive area within which touch events are to be detected; a plurality of emitters and a plurality detectors arranged around a periphery of the touch sensitive area, each emitter producing a plurality of optical beams received by a plurality of the detectors, wherein touch events disturb the optical beams; and an optical control system coupled to the emitters and detectors, the optical control system configured to; control activation of a plurality of the emitters and detectors simultaneously according to a modulation scheme comprising a plurality of different functions, each function alternating an associated one of the emitters between an activated state and a deactivated at a pattern of times varying from that of each other function in the modulation scheme, wherein in the activated state the associated emitter is emitting optical beams and in the deactivated state the associated emitter is not emitting optical beams such that the deactivated state consumes less power than the activated state; and correlate output from the detectors regarding which optical beams have been disturbed by a touch event with the different functions to determine a location within the touch sensitive area where the touch event occurred. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for determining locations of touch events within a touch sensitive area, the touch sensitive area having a plurality of emitters and a plurality of detectors arranged around its periphery, each emitters producing a plurality of optical beams received by a plurality of the detectors, wherein touch events disturb the optical beams, the method comprising:
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activating a plurality of the emitters and detectors simultaneously according to a modulation scheme comprising a plurality of different functions, each function alternating an associated one of the emitters between an activated state and a deactivated at a pattern of times varying from that of each other function in the modulation scheme, wherein in the activated state the associated emitter is emitting optical beams and in the deactivated state the associated emitter is not emitting optical beams such that the deactivated state consumes less power than the activated state; and determining a location within the touch sensitive area where a touch event occurred based on which beams have been disturbed by the touch event and based on the different functions. - View Dependent Claims (18, 19, 20)
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Specification