Optical control system with modulated emitters
First Claim
1. An optical control system comprising:
- a plurality of optical emitters and a plurality of optical detectors defining therebetween an area of optical paths whereby the transmission of energy between an emitter and a detector may be modulated by an optical interaction occurring in the vicinity of said area, wherein at least one of said detectors is positioned to receive optical energy from more than one of said optical emitters;
drive circuitry for driving a plurality of said optical emitters simultaneously according to a modulation scheme in which each emitter is modulated with a different modulation function, said functions being orthogonal relative to one another;
correlation means associated with said at least one detector for receiving an output therefrom and for correlating said output with at least those modulation functions driving the emitters which said at least one detector is positioned to receive optical energy from, to thereby determine the amount of energy incident on said at least one detector from each of said emitters.
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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 orthogonal functions, and the system is operable to correlate the signals received at the detectors with the modulation 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 modulating 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
11 Claims
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1. An optical control system comprising:
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a plurality of optical emitters and a plurality of optical detectors defining therebetween an area of optical paths whereby the transmission of energy between an emitter and a detector may be modulated by an optical interaction occurring in the vicinity of said area, wherein at least one of said detectors is positioned to receive optical energy from more than one of said optical emitters; drive circuitry for driving a plurality of said optical emitters simultaneously according to a modulation scheme in which each emitter is modulated with a different modulation function, said functions being orthogonal relative to one another; correlation means associated with said at least one detector for receiving an output therefrom and for correlating said output with at least those modulation functions driving the emitters which said at least one detector is positioned to receive optical energy from, to thereby determine the amount of energy incident on said at least one detector from each of said emitters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operating an optical control system having a plurality of optical emitters and a plurality of optical detectors defining therebetween an area of optical paths whereby the transmission of energy between an emitter and a detector may be modulated by an optical interaction occurring in the vicinity of said area, wherein at least one of said detectors is positioned to receive optical energy from more than one of said optical emitters, the method comprising the steps of:
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driving a plurality of said optical emitters simultaneously according to a modulation scheme in which each emitter is modulated with a different modulation function, said functions being orthogonal relative to one another; receiving an output from said at least one detector; correlating said output with at least those modulation functions driving the emitters which said at least one detector is positioned to receive optical energy from, to thereby determine the amount of energy incident on said at least one detector from each of said emitters.
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Specification