Capacitance detection device and capacitance detection method
AssigneeAlps Alpine Co., Ltd.
InventorsTatsumi Fujiyoshi, Atsushi Matsuda
Life of this patent
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Abstract
A capacitance detection device includes at least one detection electrode, a shield electrode disposed in close vicinity of the detection electrode, an AC signal source that supplies an AC signal to the shield electrode, a detection circuit that detects capacitance between a physical object in close vicinity of the detection electrode and the detection electrode on the basis of a detection signal output from the detection electrode and the AC signal output from the AC signal source, and a phase adjustment circuit provided between the AC signal source and the shield electrode. The phase adjustment circuit advances the phase of the AC signal output from the AC signal source.
Claims11
A capacitance detection device comprising:
- at least one detection electrode configured to output a detection signal associated with a capacitance formed between the detection electrode and an object in proximity of the detection electrode;
- an AC signal source configured to output an AC signal;
- a shield electrode disposed in a vicinity of the detection electrode, the shield electrode being to receive the AC signal;
- a detection circuit configured to detect the capacitance between the object and the detection electrode based on the detection signal received from the detection electrode and the AC signal received from the AC signal source;
- and
- a phase adjustment circuit provided between the AC signal source and the shield electrode, the phase adjustment circuit being configured to supply the AC signal to the shield electrode by advancing a phase of the AC signal output from the AC signal source.
A capacitance detection method using a capacitance detection device including at least one detection electrode and a shield electrode disposed in a vicinity of the detection electrode, the method comprising:
- outputting an AC signal from an AC signal source;
- supplying the AC signal to the shield electrode;
- outputting, from the detection electrode, a detection signal associated with a capacitance formed between the detection electrode and an object in proximity of the detection electrode;
- and
- detecting the capacitance between the object and the detection electrode based on the detection signal received from the detection electrode and the AC signal received output from the AC signal source,
- wherein the supplying the AC signal to the shield electrode includes:
- advancing a phase of the AC signal output from the AC signal source before supplying to the shield electrode.
Dependencies are inferred from the claim text.