Optical pressure sensor
AssigneeHoneywell International Inc.
InventorsDaniel W. Youngner, Son Thai Lu
Life of this patent
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Abstract
A pressure sensor is formed on a substrate, the surface of the substrate having a p-n junction and a shell with a beam inside the shell over the p-n junction. The beam and the shell and the p-n junction surface form optical Fabry-Pérot cavities. An optical fiber is positioned in a hole formed in the underside of the substrate below the p-n junction. Light from the fiber charges the p-n junction and drives it into vibration mode. Pressure changes change the tension in the diaphram to vary the frequency with changes in pressure, so that pressure can be detected.
Claims8
A pressure sensor, comprising:
- an optical fiber emitting a light beam;
- a beam to respond to changes in pressure;
- a substrate having a first surface on which said beam is mounted and having a second surface opposite said first surface, said substrate defining an opening which is open from said second surface of said substrate, said optical fiber being mounted in said opening in said substrate to direct said light beam onto said beam;
- and
- a junction in said substrate to receive a portion of said light beam which impinges said beam to drive said beam into vibration.
A method for sensing pressure, comprising the steps of:
- directing a beam of light through a junction in a semiconductor substrate and onto a beam;
- providing an optical resonant cavity between said junction and said beam to impose a frequency on said beam of light;
- vibrating said beam by electrostatic attraction between said junction and said beam;
- varying a frequency of vibration by said beam by changes in pressure to effect changes in said beam of light;
- and
- sensing said changes in said beam of light.
A method of making a pressure sensor, comprising the steps of:
- forming a p-n junction on a first surface of a substrate;
- forming a microstructure on a substrate over said p-n junction, said microstructure including a shell and a beam within said shell;
- evacuating said shell;
- forming an opening in a second surface of said substrate;
- and
- positioning an optical fiber in said opening so as to direct a beam of light onto said beam and said p-n junction to thereby charge said p-n junction and drive said beam into vibration;
- receiving light reflected from said beam, said light carrying a frequency of an optical resonant cavity formed between said p-n junction and said beam;
- and
- subjecting said shell to pressure to vary said light reflected by said beam.
Dependencies are inferred from the claim text.