Microfabricated acoustic transducer with suppressed substrate modes
AssigneeSensant Corporation
InventorsIgal Ladabaum, Paul A. Wagner
Life of this patent
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Abstract
A microfabricated acoustic transducer with suppressed substrate modes includes a diaphragm containing an upper electrode suspended above a substrate containing a lower electrode; the substrate may or may not contain electronic circuits. The substrate modes are suppressed by either thinning the substrate such that a longitudinal ringing mode occurs outside of the frequency band of interest or applying a judiciously designed damping material that absorbs acoustic energy from the substrate on the backside of the transducer substrate, or by both thinning the substrate and applying the damping material. The damping material has an acoustic impedance that matches the acoustic impedance of the substrate and is lossy.
Claims10
A microfabricated transducer assembly with suppressed acoustic modes comprising:
- a substrate having a topside, a backside and a thickness;
- a capacitive microfabricated ultrasonic transducer formed on the topside of the substrate;
- a damping material disposed on the backside of the substrate;
- and wherein:
- the thickness of the substrate is such that longitudinal ringing modes of the substrate are outside a frequency band of interest;
- the damping material is lossy;
- and
- the damping material has an acoustic impedance substantially equal to that of the substrate.
A method for suppressing acoustic modes in a microfabricated transducer assembly, the method comprising:
- providing a substrate having a topside, a backside and a thickness;
- forming a capacitive microfabricated ultrasonic transducer formed on the topside of the substrate;
- disposing a damping material disposed on the backside of the substrate;
- and wherein:
- the thickness of the substrate is such that longitudinal ringing modes of the substrate are outside a frequency band of interest;
- the damping material is lossy;
- and
- the damping material has an acoustic impedance substantially equal to that of the substrate.
Dependencies are inferred from the claim text.