Mechanical resonator sensor
AssigneeOxsensis Limited
InventorsRalf-Dieter Pechstedt, Conrad Langton, Konstantin Movsovic
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Abstract
A transducer is disclosed for detecting a property of a fluid such as pressure, using a mechanical resonator having a resonant frequency dependent upon the fluid property. The transducer also has a temperature sensing optical cavity with an optical path difference which varies in correspondence with changes in temperature of the transducer.
Claims43
A sensor for detecting one or more properties of a fluid, the sensor comprisingcomprises:
- a mechanical resonator arranged to exhibit a resonant frequency which is dependent upon one or more properties of the fluid;
- and
- a temperature sensing optical cavity arranged to vary in optical path difference in correspondence with changes in temperature of the transducer.
A sensor comprising:
- a transducer comprising a mechanical resonator arranged to exhibit a resonant frequency which is dependent upon one or more properties of the fluid and a vibration sensing optical cavity arranged to vary in optical path difference in correspondence with vibration of the mechanical resonator;
- a resonator driver arranged to drive vibration of the mechanical resonator at or near the resonant frequency;
- and
- a detector arranged to detect amplitude of vibration of the mechanical resonator, from optical interference caused by a combination of the vibration sensing optical cavity and the detector in light received at the detector from the transducer, and to detect the resonant frequency of the mechanical resonator.
A method of detecting one or more properties of a fluid using a transducer comprising a mechanical resonator arranged to exhibit a resonant frequency which is dependent upon the one or more properties, and a detector optically coupled to the transducer, the method comprising:
- providing at the transducer a temperature sensing optical cavity arranged to vary in optical path difference in correspondence with changes in temperature at the transducer;
- detecting the optical path difference of the temperature sensing optical cavity, from light received at the detector from the transducer,
- driving vibration of the mechanical resonator at or near the resonant frequency;
- detecting the vibration frequency of the mechanical resonator at the detector;
- and
- providing an output of the one or more properties of the fluid based on the detected vibration frequency of the mechanical resonator compensated for temperature using the optical path difference of the temperature sensing optical cavity.
A method of detecting one or more properties of a fluid using a transducer comprising a mechanical resonator arranged to exhibit a resonant frequency which is dependent upon the one or more properties, and a detector optically coupled to the transducer, the method comprising:
- providing at the transducer a vibration sensing optical cavity arranged to vary in optical path difference in correspondence with vibrations of the mechanical resonator;
- driving vibration of the mechanical resonator at or near the resonant frequency;
- detecting a vibration frequency of the mechanical resonator at the detector;
- detecting amplitude of vibration of the mechanical resonator, from optical interference caused by a combination of the vibration sensing optical cavity and the detector in light received at the detector from the transducer;
- and
- providing an output of the one or more properties of the fluid based on the detected vibration frequency of the mechanical resonator.
Dependencies are inferred from the claim text.