US 12,339,153 B2
Optical fabry-perot based liquid level sensors
David H. Crowne, Weybridge, VT (US)
Assigned to Simmonds Precision Products, Inc., Vergennes, VT (US)
Filed by Simmonds Precision Products, Inc., Vergennes, VT (US)
Filed on Feb. 9, 2022, as Appl. No. 17/668,003.
Prior Publication US 2023/0251122 A1, Aug. 10, 2023
Int. Cl. G01F 23/292 (2006.01); G01F 23/80 (2022.01)
CPC G01F 23/292 (2013.01) [G01F 23/804 (2022.01)] 10 Claims
OG exemplary drawing
 
1. An optical sensor comprising:
a fiber optically configured to receive an optical signal from an optical source;
a main sensor body having a known coefficient of thermal expansion, the main sensor body aligned to receive the optical signal from the fiber via a first interface and configured to reflect the optical signal from a second interface, thereby creating a peak in the reflected optical signal, the peak corresponding to a resonant wavelength corresponding to an optical path between the first and second interfaces is indicative of temperature of the main sensor body;
a plurality of standoffs projecting from the second interface and circumferentially spaced apart around an optical axis; and
an endplate supported by the plurality of standoffs thereby forming a cavity between the second interface of the main sensor body and the endplate, the cavity in fluid communication with an environment external to the cavity via openings defined between adjacent pairs of the plurality of standoffs,
wherein a resonant wavelength of the cavity is indicative of whether the cavity is filled with gas or liquid.