Synchronous timed orthogonal measurement pattern for multi-touch sensing on a touchpad
First Claim
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1. A method for detecting the presence of multiple objects on a touchpad, said method comprising:
- 1) providing a touchpad with two co-planar sets of electrodes arranged as orthogonal arrays, wherein a first set of electrodes act as drive electrodes, and a second set of electrodes act as sense electrodes;
2) simultaneously stimulating all of the drive electrodes using modulated stimulus signals having arbitrary amplitudes formed by orthogonal codes that do not have phase orthogonality, wherein all permutations of orthogonal code dot products are equal to zero; and
3) receiving measurement data regarding capacitance at each electrode junction.
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Abstract
A method for detecting multiple objects on a touchpad having a grid of orthogonal electrodes, wherein all drive electrodes are simultaneously stimulated, and then frequency or electrode coding is used to separate each electrode junction and produce a capacitance image of the touchpad surface in a single measurement sequence.
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Citations
7 Claims
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1. A method for detecting the presence of multiple objects on a touchpad, said method comprising:
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1) providing a touchpad with two co-planar sets of electrodes arranged as orthogonal arrays, wherein a first set of electrodes act as drive electrodes, and a second set of electrodes act as sense electrodes; 2) simultaneously stimulating all of the drive electrodes using modulated stimulus signals having arbitrary amplitudes formed by orthogonal codes that do not have phase orthogonality, wherein all permutations of orthogonal code dot products are equal to zero; and 3) receiving measurement data regarding capacitance at each electrode junction. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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