Micromachined apparatus utilizing box suspensions
First Claim
1. A micromachined apparatus comprising:
- a frame having a substantially rectangular perimeter;
a plurality of elongated stress relief members arranged substantially in a rectangular pattern outside of the frame perimeter, each stress relief member having at least one substrate anchor substantially at an intersection of said stress relief member with a line through midpoints of a pair of opposite frame sides; and
a plurality of box suspensions coupling corners of the frame to the plurality of stress relief members, each box suspension including a substantially rectangular array of box flexures, the box flexures at a first corner of the array coupled to the frame, the box flexures at a second corner opposite the first corner coupled respectively to ends of a pair of stress relief members but not to one another, the box suspension further including a diagonal brace coupled between third and fourth corners of the array, the box flexures at the second corner further coupled respectively about a pivot point to a plurality of support flexures, the plurality of support flexures having a substrate anchor substantially at an intersection with a line through the first and second corners.
1 Assignment
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Accused Products
Abstract
A micromachined gyroscope makes use of Coriolis acceleration to detect and measure rotation rate about a plane normal to the surface of a substrate. Specifically, various resonating structures are suspended within a frame. The resonating structures include phase and anti-phase masses that are mechanically coupled in order to produce a single resonance frequency for the entire resonating system. Rotation of the micromachined gyroscope about the plane produces a rotational force on the frame. The frame is suspended in such a way that its motion is severely restricted in all but the rotational direction. Sensors on all sides of the frame detect the rotational deflection of the frame for measuring the change in direction.
121 Citations
24 Claims
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1. A micromachined apparatus comprising:
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a frame having a substantially rectangular perimeter; a plurality of elongated stress relief members arranged substantially in a rectangular pattern outside of the frame perimeter, each stress relief member having at least one substrate anchor substantially at an intersection of said stress relief member with a line through midpoints of a pair of opposite frame sides; and a plurality of box suspensions coupling corners of the frame to the plurality of stress relief members, each box suspension including a substantially rectangular array of box flexures, the box flexures at a first corner of the array coupled to the frame, the box flexures at a second corner opposite the first corner coupled respectively to ends of a pair of stress relief members but not to one another, the box suspension further including a diagonal brace coupled between third and fourth corners of the array, the box flexures at the second corner further coupled respectively about a pivot point to a plurality of support flexures, the plurality of support flexures having a substrate anchor substantially at an intersection with a line through the first and second corners. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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- 14. A micromachined apparatus comprising a substantially rectangular array of box flexures, the box flexures at a first corner of the array coupled to a frame, the box flexures at a second corner opposite the first corner coupled respectively to ends of a pair of stress relief members but not to one another, the apparatus further including a diagonal brace coupled between third and fourth corners of the array, the box flexures at the second corner further coupled respectively at a pivot point to a plurality of support flexures, the plurality of support flexures having a substrate anchor substantially at an intersection with a line through the first and second corners.
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18. A method for reducing stresses in a micromachined apparatus, the method comprising:
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forming a plurality of micromachined structures from a common material, the micromachined structures including a frame suspended from a plurality of stress relief members by a plurality of box suspensions, each box suspension including a substantially rectangular array of box flexures, the box flexures at a first corner of the array coupled to the frame, the box flexures at a second corner opposite the first corner coupled respectively to ends of a pair of stress relief members but not to one another, the box suspension further including a diagonal brace coupled between third and fourth corners of the array, the box flexures at the second corner further coupled respectively about a pivot point to a plurality of support flexures; anchoring each of the plurality of stress relief members to a substrate substantially at an intersection of the stress relief member with a line through centers of opposite sides of the frame; and anchoring the support flexures of each of the plurality of box suspensions to the substrate using a single anchor substantially at an intersection with a line through opposite corners of the frame. - View Dependent Claims (19, 20, 21, 22)
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23. A micromachined apparatus comprising:
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a substrate; a frame supporting a number of resonating structures; suspension means for suspending the frame over and parallel to the substrate, the suspension means substantially restricting movement of the frame relative to the substrate to only rotational movement about an axis normal to the substrate; and stress reducing means for reducing stresses in the suspension means, wherein the suspension means comprises a plurality of box suspensions, each box suspension coupled at a corner of the frame and including a diagonal brace. - View Dependent Claims (24)
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Specification