The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 17, 2002
Filed:
Oct. 25, 2000
Eric Lee Goldner, Valencia, CA (US);
Michael J. Tweedy, Simi Valley, CA (US);
Samuel N. Fersht, Studio City, CA (US);
David B. Hall, La Crescenta, CA (US);
Northrop Grumman Corporation, Woodland Hills, CA (US);
Abstract
A displacement sensor and an acceleration sensor are mounted to a common support member. The displacement sensor comprises a first circular flexural disk having a natural frequency less than the frequency range of the acoustic waves of interest. Spiral-wound optical fiber coils are mounted to opposite sides of the first flexural disk. The acceleration sensor comprises a second flexural disk having a natural frequency greater than the frequency range of the acoustic waves. Spiral-wound optical fiber coils are mounted to opposite sides of the second flexural disk. A fiber optic interferometer provides an output signal that is a combination of signals output from the displacement sensor and the acceleration sensor. The displacement sensor includes an inertia ring mounted to an edge of the first flexural disk to keep it nearly stationary when an acoustic wave in the selected frequency range is incident upon the housing. The flexural disks include upper and lower rings spaced apart from the support post with portions of the disks between the rings and the support post defining hinges at which the flexural disk flex in response to acceleration of the support member along its longitudinal axis. The surfaces of the first and second flexural disks preferably include grooves extending between the upper rings and the outer edges of the flexural disks. The grooves are arranged to allow lengths of optical fiber adjacent the rings to pass under the optical fiber coils that are formed on the surfaces of the flexural disks.