Driven shield for capacitive touchpads
First Claim
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1. A method for shielding a portion of a capacitive sensor used in a touchpad, said method comprising:
- 1) providing two drive electrodes for generating a signal and one sense electrode disposed between the two drive electrodes for measuring a portion of the signal that is coupled to the one sense electrode; and
2) providing two driven shield electrodes, one driven shield electrode on each side of and between the one sense electrode and the two drive electrodes, the two driven shield electrodes being electrically coupled to the one sense electrode for receiving a modified signal from the one sense electrode, the two driven shield electrodes at least partially shielding the one sense electrode from undesired electrical and capacitive signals, including stray capacitive signals from the two drive electrodes.
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Accused Products
Abstract
A conductive shield that is disposed near the sensor, wherein a signal is driven on the shield that is similar to the signal induced on the sensor, thereby reducing stray capacitances and protecting the sensor from external noise sources, and resulting in a stronger signal reaching the sensor.
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Citations
21 Claims
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1. A method for shielding a portion of a capacitive sensor used in a touchpad, said method comprising:
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1) providing two drive electrodes for generating a signal and one sense electrode disposed between the two drive electrodes for measuring a portion of the signal that is coupled to the one sense electrode; and 2) providing two driven shield electrodes, one driven shield electrode on each side of and between the one sense electrode and the two drive electrodes, the two driven shield electrodes being electrically coupled to the one sense electrode for receiving a modified signal from the one sense electrode, the two driven shield electrodes at least partially shielding the one sense electrode from undesired electrical and capacitive signals, including stray capacitive signals from the two drive electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for shielding a capacitive sensor used in a touchpad, said system comprised of:
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two drive electrodes and means for generating a signal thereon; one sense electrode disposed between the two drive electrodes and means for measuring a portion of the signal that is coupled to the one sense electrode; and two driven shield electrodes, one disposed on each side of the one sense electrode and between the one sense electrode and the two drive electrodes, the two driven shield electrodes being electrically coupled to the one sense electrode for receiving a modified signal from the one sense electrode, and wherein the two driven shield electrodes are at least partially shielding the one sense electrode from undesired electrical and capacitive signals, including stray capacitive signals from the two drive electrodes. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A system for shielding a capacitive sensor used in a touchpad, said system comprised of:
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two drive electrodes and means for generating a signal thereon; one sense electrode disposed between the two drive electrodes and means for measuring a portion of the signal that is coupled to the one sense electrode; two driven shield electrodes; a driven shield substrate, wherein the two driven shield electrodes and the driven shield substrate are electrically coupled to the one sense electrode for receiving a modified signal from the one sense electrode, wherein the two drive electrodes, the one sense electrode and the two driven shield electrodes are coupled to the driven shield substrate, and wherein the two driven shield electrodes and the driven shield substrate are disposed adjacent to the one sense electrode to thereby at least partially shield the one sense electrode from undesired electrical and capacitive signals including stray capacitive signals from the two drive electrodes. - View Dependent Claims (18, 19)
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20. A system for shielding a capacitive sensor used in a touchpad, said system comprised of:
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two drive electrodes and means for generating a signal thereon; one sense electrode disposed between the two drive electrodes and means for measuring a portion of the signal that is coupled to the one sense electrode; and a driven shield substrate, wherein the one sense electrode and the two drive electrodes are attached to the driven shield substrate, and wherein the driven shield substrate is electrically coupled to the one sense electrode for receiving a modified signal from the one sense electrode to thereby at least partially shield the one sense electrode from undesired electrical and capacitive signals including stray capacitive signals from the two drive electrodes. - View Dependent Claims (21)
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Specification