Flexural plate wave sensor and array
AssigneeThe Charles Stark Draper Laboratory, Inc.
InventorsBrian T. Cunningham, John R. Williams
Life of this patent
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Abstract
A method for manufacturing a flexural plate wave sensor includes the steps of depositing an etch-stop layer over a substrate, depositing a membrane layer over the etch stop layer, depositing a piezoelectric layer over the membrane layer, forming a first transducer on the piezoelectric layer and forming a second transducer on the piezoelectric layer, spaced from the first transducer. The method further includes the steps of etching a cavity through the substrate, the cavity having substantially parallel interior walls, removing the portion of the etch stop layer between the cavity and the membrane layer to expose a portion of the membrane layer, and depositing an absorptive coating on the exposed portion of the membrane layer.
Claims11
A method for manufacturing a flexural plate wave sensor comprising the steps of:
- depositing an etch-stop layer over a substrate;
- depositing a membrane layer over said etch stop layer;
- depositing a piezoelectric layer over said membrane layer;
- forming a first transducer on said piezoelectric layer;
- forming a second transducer on said piezoelectric layer, spaced from said first transducer;
- etching a cavity through the substrate, the cavity having substantially parallel interior walls;
- removing the portion of the etch stop layer between the cavity and the membrane layer to expose a portion of the membrane layer;
- and
- depositing an absorptive coating on the exposed portion of the membrane layer.
A flexural plate wave sensor comprising:
- a base substrate;
- an etch stop layer disposed over said base substrate;
- a membrane layer disposed over said etch stop layer;
- a cavity disposed in said base substrate and said etch stop layer, thereby exposing a portion of said membrane layer, said cavity having substantially parallel interior walls;
- an absorptive coating disposed on the exposed portion of said membrane layer within said cavity;
- a piezoelectric layer disposed over said membrane layer;
- a first transducer disposed on said piezoelectric layer;
- and
- a second transducer disposed on said piezoelectric layer, spaced from said first transducer.
A flexural plate wave sensor array comprising:
- a substrate;
- and
- a plurality of flexural plate wave sensors, each sensor including a cavity formed in the substrate, a thin film membrane layer spanning the cavity, a piezoelectric layer disposed on the thin film membrane layer, a transducer disposed on the piezoelectric layer and a plurality of discrete absorptive coatings disposed on said thin film membrane layer within said cavity;
- wherein said cavity of each of said sensors includes interior walls which are substantially parallel to each other and to the interior walls of adjacent sensors.
Dependencies are inferred from the claim text.