Methods for determining a touch location on a touch screen
First Claim
1. A method of determining a touch coordinate on a touch screen, comprising:
- providing (i) a display, (ii) a plurality of collimating lenses along two opposite edges of the display, (iii) a plurality of light pulse emitters, denoted E, that transmit light pulses through the collimating lenses of a first of the two edges and over the display, and (iv) a plurality of light pulse receivers, denoted R, that receive the light pulses through the collimating lenses of the opposite of the two edges, and that output values, denoted OUT(E, R), representing the light pulses received by receiver R from emitter E, wherein each emitter-receiver pair (E, R) has an expected receiver output value, denoted EXP(E, R), when light pulses are not blocked, and wherein the collimating lenses are arranged in a shift-aligned fashion such that (a) light pulses emitted by each emitter are detected by at least two of the receivers, and (b) each receiver detects light pulses emitted by at least two emitters;
selecting two or more emitter-receiver pairs (E1, R1), . . . , (En, Rn) for which their actual receiver output values, OUT(E1, R1), . . . , OUT(En, Rn), deviate significantly from their expected receiver output values EXP(E1, R1), . . . , EXP(En, Rn), because either (A) light pulses transmitted by each of two emitters are being blocked from reaching a common receiver, or (B) light pulses transmitted by a common emitter are being blocked from reaching each of two receivers;
associating respective screen coordinates, denoted X(E1, R1), . . . , X(En, Rn), along a first screen axis with the selected emitter-receiver pairs; and
calculating a touch coordinate, denoted XT, by interpolating the associated screen coordinates
XT=Σ
Wi*X(Ei, Ri)with weights Wi according to the respective deviations, OUT(Ei, Ri)−
EXP (Ei, Ri), between the actual receiver output values and the expected receiver output values.
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Abstract
A method of determining a touch coordinate on a touch screen, including providing a display, a plurality of collimating lenses along two opposite edges of the display, the collimating lenses being arranged along the two edges so as to be shift-aligned relative to one another, a plurality of light pulse emitters that transmit light pulses through the collimating lenses of a first of the two edges over the display, and a plurality of light pulse receivers that receive the light pulses through the collimating lenses of the opposite of the two edges, and that output values representing the received light pulses, wherein light pulses emitted by each emitter are detected by at least two of the receivers, wherein each receiver detects light pulses emitted by at least two emitters, and wherein each receiver has expected values for emitter-receiver pairs when light pulses are not blocked, selecting receiver output values for emitter-receiver pairs that deviate significantly from corresponding receiver expected values, wherein the selected values indicate at least that light pulses transmitted by two emitters are blocked from reaching one receiver, or that light pulses transmitted by one emitter are blocked from reaching two receivers, associating a screen coordinate along a first screen axis with each selected receiver output, and calculating a touch coordinate by interpolating the associated screen coordinates according to the respective deviations between the selected receivers'"'"' output values and corresponding expected values.
138 Citations
18 Claims
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1. A method of determining a touch coordinate on a touch screen, comprising:
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providing (i) a display, (ii) a plurality of collimating lenses along two opposite edges of the display, (iii) a plurality of light pulse emitters, denoted E, that transmit light pulses through the collimating lenses of a first of the two edges and over the display, and (iv) a plurality of light pulse receivers, denoted R, that receive the light pulses through the collimating lenses of the opposite of the two edges, and that output values, denoted OUT(E, R), representing the light pulses received by receiver R from emitter E, wherein each emitter-receiver pair (E, R) has an expected receiver output value, denoted EXP(E, R), when light pulses are not blocked, and wherein the collimating lenses are arranged in a shift-aligned fashion such that (a) light pulses emitted by each emitter are detected by at least two of the receivers, and (b) each receiver detects light pulses emitted by at least two emitters; selecting two or more emitter-receiver pairs (E1, R1), . . . , (En, Rn) for which their actual receiver output values, OUT(E1, R1), . . . , OUT(En, Rn), deviate significantly from their expected receiver output values EXP(E1, R1), . . . , EXP(En, Rn), because either (A) light pulses transmitted by each of two emitters are being blocked from reaching a common receiver, or (B) light pulses transmitted by a common emitter are being blocked from reaching each of two receivers; associating respective screen coordinates, denoted X(E1, R1), . . . , X(En, Rn), along a first screen axis with the selected emitter-receiver pairs; and calculating a touch coordinate, denoted XT, by interpolating the associated screen coordinates
XT=Σ
Wi*X(Ei, Ri)with weights Wi according to the respective deviations, OUT(Ei, Ri)−
EXP (Ei, Ri), between the actual receiver output values and the expected receiver output values.- View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining a touch coordinate on a touch screen, comprising:
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providing (i) a display, (ii) a plurality of light pulse emitters, E1, . . . , En, arranged such that each emitter, E, transmits light pulses, denoted E(θ
1) and E(θ
2), that are directed in complementary directions, θ
1 and θ
2, outward from an edge of the display and over the display, and (iii) a touch detector associated with the display, the touch detector being operable to identify two or more touch locations in response to a single touch on the display, each identified touch location corresponding to a light pulse Ei(θ
j) that is partially blocked by the touch, and having (a) a normalized touch value between 0 and 1, denoted W(Ei(θ
j)), according to the percentage of blockage of light pulse Ei(θ
j)) by the touch, and (b) a respective screen coordinate, denoted X(Ei(θ
j)); andcalculating a touch coordinate, denoted XT, comprising interpolating the screen coordinates of the identified touch locations according to the identified touch locations'"'"' normalized touch values,
XT=Σ
W(Ei(θ
j))*X(Ei(θ
j)). - View Dependent Claims (8, 9, 10)
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11. A method of pairing disambiguating unpaired x- and y- coordinate values detected by a touch screen system in response to two simultaneous touches, comprising:
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providing (i) a display, (ii) a plurality of light pulse emitters that transmit light pulses over the display, and (iii) a plurality of light pulse receivers that receive the light pulses, and that output values representing the received light pulses wherein each receiver has expected values for emitter-receiver pairs when the light pulses are not blocked; detecting two different x-coordinates corresponding to two simultaneous touches, based on significant deviations between actual receiver output values for receiver-emitter pairs and corresponding expected receiver output values; separately detecting two different y-coordinates corresponding to the two simultaneous touches; determining which one of the two x-coordinates is associated with a touch that is nearer to an edge of the display, based on the deviations corresponding to the x-coordinates; and pairing the thus-determined x-coordinate with the y-coordinate that is closer to that one edge. - View Dependent Claims (12, 13, 14)
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15. A method of discriminating clockwise gestures from counter-clockwise gestures in a touch screen system, comprising:
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providing (i) a display, (ii) a plurality of light pulse emitters that transmit light pulses over the display, and (iii) a plurality of light pulse receivers that receive the light pulses, and that output values representing the received light pulses, wherein each receiver has expected values for emitter-receiver pairs when the light pulses are not blocked; performing a series of touch detections at times t1, . . . , tn, each touch detection at a given time t detecting two different x-coordinates, x1(t) and x2(t), corresponding to two touches, and separately detecting two different y-coordinates, y1(t) and y2(t), corresponding to the two touches, the touch detections being based on significant deviations between actual receiver output values for receiver-emitter pairs and corresponding expected receiver output values; determining which of the two series of detected x-coordinates, (x1(t1), . . . , x1(tn)) and (x2(t1), . . . , x2(tn)), is associated with a touch approaching a display edge, by comparing the deviations corresponding to neighboring x-coordinates; and discriminating a gesture as being clockwise or counter-clockwise by pairing the thus-determined series of the x-coordinates with that one of the series of detected y-coordinates, (y1(t1), . . . , (y1(tn) and (y2(t1), . . . , (y2(tn), that is also approaching that display edge. - View Dependent Claims (16, 17, 18)
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Specification