Fiber optic MEMS seismic sensor with mass supported by hinged beams
First Claim
Patent Images
1. A fiber optic MEMS seismic sensor comprising:
- a frame;
a proof mass supported by the frame, the proof mass having a hole formed therein, the hole movable with respect to the frame; and
a sensor gap defined between a first reflector and a second reflector, the first reflector located adjacent the proof mass at a first end of the hole, the second reflector located at an opposite end of the hole, wherein the second reflector is bonded to the proof mass.
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Abstract
The present invention relates to an optic seismic MEMS sensor. More specifically, a proof mass is supported by a frame having supporting beams. The proof mass is positioned within the frame and has a hinged attachment to the beams. The proof mass has a sensor gap having a first reflector and a second reflector positioned at opposing ends of the sensor gap. An optical fiber injects light into the sensor gap and light is reflected to determine seismic movement of the proof mass with respect to the frame. Stops are provided for limiting the movement of the proof mass to minimize strain on the attachment of the beams and the proof mass.
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Citations
20 Claims
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1. A fiber optic MEMS seismic sensor comprising:
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a frame; a proof mass supported by the frame, the proof mass having a hole formed therein, the hole movable with respect to the frame; and a sensor gap defined between a first reflector and a second reflector, the first reflector located adjacent the proof mass at a first end of the hole, the second reflector located at an opposite end of the hole, wherein the second reflector is bonded to the proof mass. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A fiber optic MEMS sensor, the sensor comprising:
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a frame having supporting beams extending therefrom; a proof mass having a hinged attachment to the beams, the proof mass movable with respect to the frame, the proof mass having a hole formed therein, the hole is an aperture extending through the proof mass to a silicon dioxide surface at bottom of proof mass; and an optical assembly injecting light into the hole, wherein the hole has a coating at an end distal to the optical assembly, the coating capable of reflecting a portion of the light to determine a sensor gap. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of manufacturing a MEMS fiber optic sensor comprising the steps of:
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providing a silicon wafer having a plurality of layers; etching a first layer of the wafer to define a sensor gap cavity, a proof mass and a frame, a portion of the sensor gap being a hole extending through the first layer of the wafer and the proof mass, the frame having beams positioned to support the proof mass; and depositing a reflective coating on the bottom of the hole in the proof mass. - View Dependent Claims (17, 18, 19, 20)
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Specification