Multi-layer capacitive transducer
First Claim
1. A capacitive transducer of multi-layered construction comprising:
- a fixed frame;
a first rotor plate including two sides, said first rotor plate being electrically grounded, and movable with respect to said fixed frame;
a second rotor plate including two sides, said second rotor plate being movable with respect to said fixed frame;
a plurality of flexible springs supporting said rotor plates, the springs each including two ends, each end having a pre-determined width;
a stem separating and rigidly connecting said first rotor plate with said second rotor plate;
a drive electrode;
a pickup electrode including two sides, said pickup electrode being disposed between said drive electrode and said first rotor plate;
a dielectric spacer rigidly connected to said frame, separating and rigidly connecting said drive electrode and said pickup electrode, a gap spacer disposed between said pickup electrode and said first rotor plate, said gap spacer defining a nominal gap spacing between said pickup electrode and said first rotor plate, said gap spacer including an opening larger that said first rotor plate, whereby said opening in said gap spacer allows said rotor plate to move towards said pickup electrode by a deflection of said flexible springs.
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Accused Products
Abstract
A capacitive transducer of multi-layer construction includes two rotor plates supported by flexible springs, the plates being spaced apart and rigidly connected by a stem. One rotor plate my be used as either a pickup electrode or a grounded target electrode for determining position, displacement, or load force. The second rotor plate may be used for electrostatic actuation without interfering with or destroying circuitry associated with the first rotor plate. A number of improvements are disclosed including a hollow rotor plate structure for reduced moving mass, buckling resistant features for the springs, improved spring anchor joint design for reduced creep and hysteresis, and material selection and matching for reduced thermal sensitivity.
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Citations
15 Claims
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1. A capacitive transducer of multi-layered construction comprising:
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a fixed frame;
a first rotor plate including two sides, said first rotor plate being electrically grounded, and movable with respect to said fixed frame;
a second rotor plate including two sides, said second rotor plate being movable with respect to said fixed frame;
a plurality of flexible springs supporting said rotor plates, the springs each including two ends, each end having a pre-determined width;
a stem separating and rigidly connecting said first rotor plate with said second rotor plate;
a drive electrode;
a pickup electrode including two sides, said pickup electrode being disposed between said drive electrode and said first rotor plate;
a dielectric spacer rigidly connected to said frame, separating and rigidly connecting said drive electrode and said pickup electrode, a gap spacer disposed between said pickup electrode and said first rotor plate, said gap spacer defining a nominal gap spacing between said pickup electrode and said first rotor plate, said gap spacer including an opening larger that said first rotor plate, whereby said opening in said gap spacer allows said rotor plate to move towards said pickup electrode by a deflection of said flexible springs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification