Micromechanical inertial sensor
First Claim
1. A micromechanical inertial sensor comprising:
- a substrate supporting a pair of spaced-apart fixed structures;
a proof mass disposed between the fixed structures and oriented lengthwise along a first axis which extends between the fixed structures, the proof mass being adapted to vibrate along a second axis substantially orthogonal to the first axis and being movable along a third axis substantially orthogonal to the first and second axes;
a sensor system adapted to detect position of the proof mass and provide a signal varying with movement of the proof mass along the third axis; and
a beam connected between each end of the proof mass and an adjacent one of the fixed structures, the beams suspending the proof mass above the substrate such that the proof mass is movable along the third axis, the beams being adapted to bend to permit vibration of the proof mass along the second axis, each beam being bowed over at least a portion of the length thereof so as to make the beam compliant in the direction of the first axis.
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Accused Products
Abstract
A micromechanical inertial sensor includes a pair of proof masses suspended between a pair of fixed structures by beams attached between the ends of the proof masses and the fixed structures, such that the proof masses extend lengthwise along a first axis direction and are able to vibrate back and forth along a second axis substantially orthogonal to the first axis. Each beam attached to the proof masses has increased compliance in the first axis direction, relative to a linear beam of equivalent cross section, such that the beams have reduced resistance to stretching in the first axis direction as the proof masses vibrate in the second axis direction. In one embodiment of the invention, each beam is bowed or curved. Alternatively, compliance of the beam is increased by providing strain relief at one or both ends of the beam, or by providing an extensible portion in each beam.
123 Citations
12 Claims
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1. A micromechanical inertial sensor comprising:
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a substrate supporting a pair of spaced-apart fixed structures; a proof mass disposed between the fixed structures and oriented lengthwise along a first axis which extends between the fixed structures, the proof mass being adapted to vibrate along a second axis substantially orthogonal to the first axis and being movable along a third axis substantially orthogonal to the first and second axes; a sensor system adapted to detect position of the proof mass and provide a signal varying with movement of the proof mass along the third axis; and a beam connected between each end of the proof mass and an adjacent one of the fixed structures, the beams suspending the proof mass above the substrate such that the proof mass is movable along the third axis, the beams being adapted to bend to permit vibration of the proof mass along the second axis, each beam being bowed over at least a portion of the length thereof so as to make the beam compliant in the direction of the first axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of reducing dependence of the apparent resonant frequency of a proof mass of a micromechanical inertial sensor on drive amplitude of the proof mass, comprising the steps of:
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disposing the proof mass between a pair of spaced-apart fixed structures with a lengthwise dimension of the proof mass oriented along a first axis which extends between the fixed structures; suspending the proof mass between the fixed structures by beams connected between each end of the proof mass and an adjacent one of the fixed structures, such that the proof mass can be forced to vibrate back-and-forth along a second axis substantially orthogonal to the first axis, and such that the proof mass is movable along a third axis which is substantially orthogonal to the first and second axes; and configuring the beams such that at least a portion of each beam is bowed so as to make the beam compliant in a direction parallel to the first axis. - View Dependent Claims (10, 11, 12)
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Specification