Z axis accelerometer design with offset compensation
First Claim
1. A teeter-totter type accelerometer comprising:
- a substrate;
at least one anchor supported by the substrate;
at least one platform supported by the substrate;
a teeter-totter proof mass coupled to the at least one platform by at least one spring and configured for pivoting about an axis of rotation through the at least one anchor in the presence of accelerations that are in a direction normal to the substrate, wherein the at least one spring is off-axis with the axis of rotation of the proof mass;
at least one sense electrode positioned to allow for sensing such pivoting of the teeter-totter proof mass; and
at least one platform-sensing electrode positioned to allow for sensing position of the platform relative to the substrate.
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Accused Products
Abstract
A teeter-totter type accelerometer includes one or more platforms configured so as to move in proportion to deformation of the substrate and/or anchor(s). The platform(s) may be in a fixed position relative to the substrate, e.g., by being fixedly attached to the anchor(s) or by being fixedly attached to the substrate, or the platform(s) may be movable relative to the substrate, e.g., by being tethered to the anchor(s) so as to allow the platform(s) to pivot relative to the anchor(s). Electrodes are placed on the substrate underlying the platform(s) for sensing position of the platform(s) relative to the underlying substrate. The teeter-totter proof mass is configured such that it can rotate relative to the platform(s), e.g., by being tethered to the platform(s) or by being tethered to one or more anchors separate from the platform(s). The output of the accelerometer is adjusted based on signals from these platform-sensing electrodes in order to reduce or eliminate offset drift.
78 Citations
19 Claims
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1. A teeter-totter type accelerometer comprising:
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a substrate; at least one anchor supported by the substrate; at least one platform supported by the substrate; a teeter-totter proof mass coupled to the at least one platform by at least one spring and configured for pivoting about an axis of rotation through the at least one anchor in the presence of accelerations that are in a direction normal to the substrate, wherein the at least one spring is off-axis with the axis of rotation of the proof mass; at least one sense electrode positioned to allow for sensing such pivoting of the teeter-totter proof mass; and at least one platform-sensing electrode positioned to allow for sensing position of the platform relative to the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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- 15. An accelerometer output circuit for a teeter-totter type accelerometer having a substrate, at least one anchor supported by the substrate, a platform attached to the at least one anchor, a teeter-totter proof mass coupled to the platform by at least one spring such that the teeter-totter proof mass is capable of pivoting about an axis of rotation through the at least one anchor in the presence of accelerations that are in a direction normal to the substrate, wherein the at least one spring is off-axis with the axis of rotation of the proof mass, at least one sense electrode positioned to allow for sensing such pivoting of the teeter-totter proof mass, and at least one platform-sensing electrode positioned to allow for sensing position of the platform relative to the substrate, the accelerometer output circuit configured to receive signals from the at least one sense electrode and the at least one platform-sensing electrode and to produce an accelerometer output signal based on the signals received from the at least one sense electrode and the at least one platform-sensing electrode.
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18. A teeter-totter type accelerometer comprising:
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a substrate; at least one anchor supported by the substrate; at least one platform supported by the substrate, the at least one platform being coupled to the at least one anchor by at least one first tether and configured for pivoting about the at least one anchor; a teeter-totter proof mass coupled to the at least one platform by at least one second tether and configured for pivoting about the at least one anchor in the presence of accelerations that are in a direction normal to the substrate; at least one sense electrode positioned to allow for sensing such pivoting of the teeter-totter proof mass; and at least one platform-sensing electrode positioned to allow for sensing position of the platform relative to the substrate. - View Dependent Claims (19)
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Specification