OPTICAL TOUCH SCREEN USING TOTAL INTERNAL REFLECTION
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Abstract
A method for use by a touch screen in which light transmitted inside the screen is scattered by an object touching the screen from outside the screen, the method including activating emitter-receiver pairs for a plurality of emitters and receivers while an object is touching a screen from outside the screen, wherein light emitted by each emitter is transmitted inside the screen, wherein each emitter is associated with a limited number of receivers that detect significant light from such emitter while no object is touching the screen, and wherein the activated emitter-receiver pairs include pairs for which the receiver is not associated with the emitter in the pair, determining that receivers not associated with emitters detect significant light due to the object scattering the light emitted by the emitters, and deriving the location where the object is touching the screen from the determining.
8 Citations
28 Claims
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1-20. -20. (canceled)
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21. A method for use by a processor of a light-based touch screen system in which light transmitted inside the screen is scattered by an object touching the screen from outside the screen, for detecting locations of multiple objects simultaneously touching the screen, the method comprising:
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activating emitter-receiver pairs for a plurality of emitters and receivers while multiple objects are simultaneously touching a screen from outside the screen, wherein light emitted by each emitter is transmitted inside the screen, and wherein for each emitter-receiver pair a reference amount of light is detected at the receiver while no object is touching the screen; identifying emitter-receiver pairs activated by said activating for which the receiver of the pair detects an amount of light different than the reference amount for the pair, whereby the identities of the identified emitter-receiver pairs alone does not suffice to disambiguate between alternative possibilities of locations at which the multiple objects are touching the screen; determining emitter-receiver pairs that are able to discriminate between the alternative possibilities of locations, based on different amounts of light, emitted by an emitter and scattered by one or more objects touching the screen, that are detected by different receivers; further activating the emitter-receiver pairs determined by said determining; and based on the amounts of light detected by the receivers for the further activated emitter-receiver pairs, determine the respective locations of the multiple objects touching the screen. - View Dependent Claims (22)
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23. A method for use by a processor of a light-based touch screen system in which light transmitted inside the screen is scattered by an object touching the screen from outside the screen, for detecting locations of multiple objects simultaneously touching a screen, the method comprising:
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activating emitter-receiver pairs for a plurality of emitters and receivers while multiple objects are simultaneously touching a screen from outside the screen, wherein light emitted by each emitter is transmitted inside the screen, wherein for each emitter-receiver pair a reference amount of light is detected at the receiver while no object is touching the screen, and wherein each emitter-receiver pair corresponds to a path crossing the screen; identifying emitter-receiver pairs for which the amount of light detected by the receiver of the pair is different than the reference amount of light for the pair; further identifying path intersection locations for the paths corresponding to the identified emitter-receiver pairs; determining emitter-receiver pairs whose corresponding paths pass over or nearly pass over the identified path intersection locations; further activating at least some of the emitter-receiver pairs determined by said determining; and based on the amounts of light detected by the receivers for the further activated emitter-receiver pairs, determining the respective locations of the multiple objects touching the screen. - View Dependent Claims (24)
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25. A method for use by a processor of a light-based touch screen system in which light transmitted inside the screen is scattered by an object touching the screen from outside the screen, for detecting location of an object touching a screen, the method comprising:
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activating emitter-receiver pairs for a plurality of emitters and receivers while an object is touching a screen from outside the screen, wherein light emitted by each emitter is transmitted inside the screen, wherein each emitter is associated with a limited number of receivers that detect significant light from such emitter while no object is touching the screen, and wherein the activated emitter-receiver pairs include pairs for which the receiver is not associated with the emitter in the pair; determining that receivers not associated with emitters detect significant light due to the object scattering the light emitted by the emitters; and deriving the location where the object is touching the screen from said determining. - View Dependent Claims (26)
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27. A method for use by a processor of a light-based touch screen system in which light transmitted inside the screen is scattered by an object touching the screen, for detecting locations of multiple objects simultaneously touching a screen, the method comprising:
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receiving amounts of light detected by a plurality of m+n light detectors while multiple objects are simultaneously touching a screen, the light being emitted by light emitters and transmitted inside the screen, whereby the light emitters correspond to a plurality of coordinates x1, . . . , xM, y1, . . . , yN and the light detectors also correspond to the plurality of coordinates x1, . . . , xM, y1, . . . , yN; identifying amounts of light detected by K+L detectors, namely, those detectors corresponding to coordinates x1, . . . , xK, y1, . . . , yL, where 2≦
K≦
M and 2≦
L≦
N, the amounts of light being different than reference values detected while no objects touch the screen;activating at least some of the 2KL (emitter, receiver) pairs (x1, y1), . . . , (x1, yL), . . . , (xK, y1), . . . , (xK, yL), (y1, x1), . . . , (y1, xK), . . . , (yL, x1), . . . , (yL, XK); and based on the amounts of light detected by the receivers of each activated (emitter, receiver) pair, determining the respective locations of the multiple objects touching the screen. - View Dependent Claims (28)
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Specification