Pre-collapsed CMUT with mechanical collapse retention
AssigneeKoninklijke Philips Electronics N.V.
InventorPeter Dirksen
Life of this patent
Estimating the term…
Abstract
A CMUT transducer cell suitable for use in an ultrasonic CMUT transducer array has a membrane with a first electrode, a substrate with a second electrode, and a cavity between the membrane and the substrate. The CMUT is operated in a precollapsed state by biasing the membrane to a collapsed condition with the floor of the cavity, and a lens is cast over the collapsed membrane. When the lens material has polymerized or is of a sufficient stiffness, the bias voltage is removed and the lens material retains the membrane in the collapsed state.
Claims20
An array of CMUT transducer cells comprising at least one CMUT transducer cell comprising:
- a substrate;
- a second electrode attached to the substrate;
- a movable membrane formed in spaced relationship to the second electrode to form a cavity having a top and a floor;
- a first electrode attached to the movable membrane;
- and
- a retention member overlaying the movable membrane when the movable membrane is collapsed to a precollapsed state by application of pressure or a bias voltage, wherein the movable membrane comprises a curvature in the precollapsed state, the retention member comprising a protrusion having a curved shape that is directly in continuous contact with the first electrode and the movable membrane at the curvature of the movable membrane so as to retain the movable membrane in its precollapsed state in the absence of the applied pressure or bias voltage such that a portion of the movable membrane is continually in contact with the floor of the cavity in the precollapsed state,
- wherein the first electrode is attached to the movable membrane at the curvature of the movable membrane.
A CMUT transducer cell comprising:
- a substrate;
- a second electrode attached to the substrate;
- a movable membrane formed in spaced relationship to the second electrode to form a cavity having a top and a floor;
- a first electrode attached to the movable membrane;
- a retention member overlaying the movable membrane, wherein the movable membrane comprises a curvature, the retention member comprising a protrusion having a curved shape that is directly in continuous contact with the first electrode and the movable membrane at the curvature of the movable membrane so as to retain the movable membrane in its precollapsed state in an absence of applied pressure or bias voltage, wherein the precollapsed state comprises a portion of the movable membrane continually in contact with the floor of the cavity;
- and
- a voltage source coupled to the transducer cell and configured to apply a bias voltage applied to the first and second electrodes, wherein the first electrode is attached to the movable membrane at the curvature of the movable membrane.
Dependencies are inferred from the claim text.