Accelerometer with reduced extraneous vibrations owing to improved return movement
First Claim
1. An accelerometer using variations in capacitance to detect the movement of a moving mass, the accelerometer comprising:
- the moving mass and a fixed part;
a first series of moving electrodes solidly connected to the moving mass and interdigitated with a second series of fixed electrodes solidly connected to the fixed part, wherein each moving electrode forms, with an adjacent fixed electrode, a variable capacitance depending on the position of the moving mass; and
an electronic circuit, the electronic circuit to detect the variation of at least one capacitance between the moving mass and the fixed part as an indicator of the displacement of the moving mass from an initial position, and to generate an electrostatic repeated return force for returning the moving mass to an initial position, the electronic circuit to generate the electrostatic repeated return force in response to a previous displacement measurement, wherein said electrostatic repeated return force is specifically selected so that a frequency mechanical power spectrum of the electrostatic repeated return force has a substantially zero power zone at the mechanical resonance frequency of the electrodes of the moving mass and of the fixed part.
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Accused Products
Abstract
An accelerometer uses variations in capacitance to detect and measure the movement of a moving mass in relation to a fixed part. The accelerometer comprises a first series of electrodes, which are solidly connected to the mass and which are interdigitated with a second series of electrodes. The second series of electrodes are solidly connected to the fixed part. The accelerometer further comprises an electronic circuit which: detects the variation in at least one capacitance between the moving mass and the fixed part, in the form of a moving mass displacement indicator; and also generates an electrostatic stress in order to return the moving mass to the initial position thereof.
13 Citations
14 Claims
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1. An accelerometer using variations in capacitance to detect the movement of a moving mass, the accelerometer comprising:
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the moving mass and a fixed part; a first series of moving electrodes solidly connected to the moving mass and interdigitated with a second series of fixed electrodes solidly connected to the fixed part, wherein each moving electrode forms, with an adjacent fixed electrode, a variable capacitance depending on the position of the moving mass; and an electronic circuit, the electronic circuit to detect the variation of at least one capacitance between the moving mass and the fixed part as an indicator of the displacement of the moving mass from an initial position, and to generate an electrostatic repeated return force for returning the moving mass to an initial position, the electronic circuit to generate the electrostatic repeated return force in response to a previous displacement measurement, wherein said electrostatic repeated return force is specifically selected so that a frequency mechanical power spectrum of the electrostatic repeated return force has a substantially zero power zone at the mechanical resonance frequency of the electrodes of the moving mass and of the fixed part. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification