Capacitive transducer feedback-controlled by means of electrostatic force and method for controlling the profile of the transducing element in the transducer
First Claim
1. A capacitive transducer, feedback-controlled by electrostatic force, comprising:
- a transducing element sensitive to a variable being measured and being at least on its surface electrically conductive to form a first electrode of the transducer, andat least two second electrodes having substantially equal effective areas which are aligned essentially parallel to a longitudinal axis of said transducing element and placed on the same side with respect to said first electrode wherein said second electrodes measure a profile of the transducing element, anda controller controlling said second electrodes to maintain the profile of said transducing element.
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Abstract
The invention is related to a capacitive transducer feedback-controlled by means of electrostatic force and a method for controlling said transducer. The transducer comprises a body part (8) supporting a dynamically moving transducing element sensitive to the variable being measured, said transducing element being, e.g., a diaphragm (9) or a reference mass (36) supported by a bending beam (37), said element further being at least on its surface electrically conductive to the end of forming a first electrode (9, 36) of the transducer, and the transducer further comprising at least two second, planar electrodes (5, 6) which are placed on the same side with regard to the transducing element (9, 37). According to the invention, the second electrodes (5, 6) have at least essentially equal effective areas to the end of measuring the profile of the transducing element (9, 37) and controlling the same to an exactly defined geometric state.
44 Citations
20 Claims
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1. A capacitive transducer, feedback-controlled by electrostatic force, comprising:
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a transducing element sensitive to a variable being measured and being at least on its surface electrically conductive to form a first electrode of the transducer, and at least two second electrodes having substantially equal effective areas which are aligned essentially parallel to a longitudinal axis of said transducing element and placed on the same side with respect to said first electrode wherein said second electrodes measure a profile of the transducing element, and a controller controlling said second electrodes to maintain the profile of said transducing element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 19, 20)
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11. A method for controlling the geometric profile of a movable transducing element in a capacitive transducer comprising the steps of:
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measuring the geometric profile of the movable transducing element with at least two second electrodes which are aligned essentially parallel to a longitudinal axis of the movable element and are placed on the same side with respect to the movable transducing element, generating an electric transducer potential in the movable transducing element, applying an opposed electric potential to the at least two second electrodes to generate an electric field between the movable transducing element and the two second electrodes, and controlling the geometric profile of the movable transducing element using at least one of the second electrodes by varying the electric transducer potential in relation to the opposed electric potential. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification