Ceramic resonance type electrostatic sensor apparatus
AssigneeMurata Mfg. Co., Ltd.
InventorsNoboru Masuda, Tetsuo Ohsawa, Takashi Sugimura
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Abstract
A ceramic resonance type electrostatic sensor apparatus with an oscillator at a fixed frequency including a first ceramic resonator which has a fixed resonance frequency, a detecting unit for detecting a capacitance between the detecting unit and an object to be detected, a resonating circuit including a second ceramic resonator and having a resonance point which varies with the small change in capacitance detected by the detecting unit, a high impedance circuit connected between the oscillator and the resonating circuit, and a high impedance circuit connected between the resonating circuit and the detecting circuit.
Claims24
A ceramic resonance type electrostatic sensor apparatus comprising an oscillator including a ceramic resonator, said first ceramic resonator having a fixed resonance frequency, and said oscillator to oscillate at a fixed frequency;
- a detecting unit for detecting capacitance between said detecting unit and an object to be detected;
- a resonating circuit including a second ceramic resonator and having a resonance point which varies with a small change in capacitance detected by said detecting unit, a high-impedance circuit connected between said oscillator and said resonating circuit and a high-impedance circuit connected between said resonating circuit and said detecting circuit thereby eliminating mutual interference between said oscillator and said resonating circuit.
A ceramic resonance type electrostatic sensor apparatus comprising:
- an oscillator adapted for oscillating at a fixed frequency, including a first ceramic resonator having a fixed resonance point;
- a detecting unit for detecting capacitance between said detecting unit and an object to be detected;
- a C-L converter for converting the capacitance detected by said detecting unit into inductance;
- a resonating circuit including a second resonator having a resonance point which varies with a small change in inductance output from said C-L converter;
- and
- a high-impedance circuit connected between said oscillator and said resonating circuit and a high-impedance circuit connected between said resonating circuit and said detecting circuit.
A ceramic resonance type electrostatic sensor apparatus comprising a variable capacitance diode connected to said ceramic resonator through a capacitor, a variable potential converter for variably adjusting an operating voltage to be applied to said variable capacitance diode, and a high frequency separating circuit connected between said variable potential converter;
- and wherein said oscillator includes a first ceramic resonator, said first ceramic resonator having a fixed resonance frequency, and said oscillator is adapted to oscillate at a fixed frequency;
- a detecting unit for detecting a capacitance between said detecting unit and an object to be detected;
- a resonating circuit including a second ceramic resonator and having a resonance point which varies with the small change in capacitance detected by said detecting unit, and high-impedance circuits for respectively connecting to input and output stages of said second ceramic resonator of said resonating circuit thereby eliminating mutual interference between said oscillator and said resonating circuit.
A dielectric resonance type electrostatic sensor apparatus, comprising:
- an oscillator including a first dielectric resonator for oscillating at a predetermined frequency;
- a detecting means for detecting a capacitance between said detecting means and an object to be detected;
- a resonating circuit including a second dielectric resonator and having a resonance frequency which is shifted with the small change in capacitance detected by said detecting means;
- a high-impedance converter for connecting between said oscillator and said resonating circuit whereby eliminating mutual interference between said oscillator and said resonating circuit;
- a detecting circuit for detecting an output from said resonating circuit;
- and
- a high-impedance circuit for connection between said resonating circuit and said detecting circuit.
A dielectric resonance type electrostatic sensor apparatus, comprising:
- an oscillator including a first dielectric resonator for oscillating at a predetermined frequency;
- a detecting means for detecting a capacitance between said detecting means and an object to be detected;
- a resonating circuit including a second dielectric resonator and having a resonance frequency which is changed with the small change in capacitance detected by said detecting means;
- a high impedance converter for connecting between said oscillator and said resonating circuit, thereby eliminating mutual interference between said oscillator and said resonating circuit;
- a detecting circuit for detecting an output from said resonating circuit;
- an AFC circuit for connection between said resonating circuit and said detecting circuit;
- and
- a high impedance circuit for connection between said resonating circuit and said detecting circuit.
Dependencies are inferred from the claim text.