Capacitive Sensor with Reduced Noise
First Claim
1. A capacitive touch sensor comprising a dielectric panel overlying a drive electrode, a first sense electrode and a second sense electrode, the electrodes being separated by coupling gaps, wherein the second sense electrode is positioned to be shielded from the drive electrode by the first sense electrode, so that in use the first sense electrode receives the majority of charge coupled from the drive electrode and the second sense electrode primarily registers noise.
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Accused Products
Abstract
A capacitive touch sensor of the type employing adjacent drive and sense electrodes, in which an additional sense electrode Y1 is provided as well as the conventional drive electrode Xn and sense electrode Y0. The drive and two sense electrodes are arranged on the bottom side of a dielectric panel, the top side providing—a sensing surface to be touched by a user'"'"'s finger or a stylus. The additional sense electrode is positioned on the underside of the dielectric panel so that it is shielded from the drive electrode by the conventional sense electrode. As a consequence, the conventional sense electrode is much more sensitive to the proximity of the finger or stylus than the additional sense electrode which primarily registers noise. The signal collected form the additional sense electrode is then subtracted from the signal collected from the conventional sense electrode, thereby to cancel noise. Another design provides similar functionality with a capacitive touch sensor of the type employing single-ended electrodes.
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Citations
12 Claims
- 1. A capacitive touch sensor comprising a dielectric panel overlying a drive electrode, a first sense electrode and a second sense electrode, the electrodes being separated by coupling gaps, wherein the second sense electrode is positioned to be shielded from the drive electrode by the first sense electrode, so that in use the first sense electrode receives the majority of charge coupled from the drive electrode and the second sense electrode primarily registers noise.
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7. A method of capacitive touch sensing comprising:
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providing a capacitive touch sensor comprising a dielectric panel overlying a drive electrode, a first sense electrode and a second sense electrode, the electrodes being separated by coupling gaps, wherein the second sense electrode is positioned to be shielded from the drive electrode by the first sense electrode; actuating the drive electrode to couple the majority of charge from the drive electrode to the first sense electrode; sampling the first sense electrode to collect a first signal sample; sampling the second sense electrode to collect a second signal sample; subtracting the second signal sample from the first signal sample to obtain a final signal; and outputting the final signal. - View Dependent Claims (8)
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- 9. A capacitive touch sensor comprising a dielectric panel overlying a measurement electrode and a noise electrode separated by a gap, wherein the measurement electrode is located at an input area and the noise electrode is positioned adjacent thereto, so that in use the measurement electrode receives the majority of charge coupled from a pointing object and the noise electrode primarily registers noise.
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11. A method of capacitive touch sensing comprising:
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providing a capacitive touch sensor comprising a dielectric panel overlying a measurement electrode and a noise electrode separated by a gap, wherein the measurement electrode is located at an input area and the noise electrode is positioned adjacent thereto; sampling the measurement electrode to collect a first signal sample; sampling the noise electrode to collect a second signal sample; subtracting the second signal sample from the first signal sample to obtain a final signal; and outputting the final signal. - View Dependent Claims (12)
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Specification