Capacitive micromachined ultrasonic transducer with multiple deflectable membranes

Patent metadata

Field	Value
Publication number	US-2016016198-A1
Application number	US-201414772517-A
Country	US
Kind code	A1
Filing date	Mar 3, 2014
Priority date	Mar 5, 2013
Publication date	Jan 21, 2016
Grant date	—

Abstract

A capacitive micromachined ultrasonic transducer (CMUT) having at least two deflectable membranes. The membranes are spaced from each other, and the membranes contribute to and/or are responsive to receive or transmit an ultrasonic signal. Spacing between the at least two deflectable membranes is adjustable through application of a voltage to cause deflection of at least one of the deflectable membranes, to affect the receive/transmit properties of the CMUT.

First claim

1 . A capacitive micromachined ultrasonic transducer (CMUT) comprising:
at least two deflectable membranes; each of the at least two deflectable membranes being spaced from each other; the at least two deflectable membranes contributing to and/or being responsive to receive or transmit an ultrasonic signal; and spacing between the at least two deflectable membranes being adjustable through application of a voltage to cause deflection of at least one of the deflectable membranes, to affect the receive/transmit properties of the CMUT.

2 . The CMUT of claim 1 further comprising a static membrane spaced apart from the at least two deflectable membranes.

3 . The CMUT of claim 1 further comprising at least one electrical contact permitting electrical connection with at least a signal source, the at least one electrical contact being in electrical connection with at least one deflectable membrane.

4 . The CMUT of claim 3 further comprising at least a second electrical contact permitting electrical connection with a ground.

5 . The CMUT of claim 1 further comprising at least one support for spacing the at least two deflectable membranes from each other.

6 . The CMUT of claim 5 further comprising a substrate supporting the at least one support.

7 . The CMUT of claim 1 further comprising a substrate supporting at least one deflectable membrane.

8 . The CMUT of claim 7 wherein the at least one deflectable membrane is anchored to the substrate.

9 . The CMUT of claim 7 wherein the at least one deflectable membrane is anchored to the substrate via an intermediary support.

10 . The CMUT of claim 1 wherein there are two deflectable membranes.

11 . The CMUT of claim 1 further comprising an insulator positioned to insulate at least one of the deflectable membranes from at least one other static or deflectable membrane.

12 . The CMUT of claim 1 wherein the CMUT is fabricated using a sacrificial layer technique.

13 . The CMUT of claim 1 wherein the CMUT is fabricated using a bonding process.

14 . A method of operating the CMUT of claim 1 comprising:
applying a respective DC biasing voltage to at least one of the deflectable membranes to space the at least one deflectable membrane at an initial separation from another deflectable membrane; and
applying a respective AC driving voltage to at least a same or different one of the deflectable membrane.

15 . The method of claim 14 , further comprising:
applying respective DC biasing voltages to each of the deflectable membranes to space the deflectable membranes at initial separations from each other; and applying respective AC driving voltages to each of the deflectable membranes.

16 . The method of claim 14 wherein the DC biasing voltage applied to at least one deflectable membrane is different from the DC biasing voltage applied to at least another one deflectable membrane.

17 . The method of claim 14 wherein the AC driving voltage applied to at least one deflectable membrane is different from the AC driving voltage applied to at least another one deflectable membrane.

18 . The method of claim 14 wherein the respective DC biasing voltages are selected to space the deflectable membranes at a selected separation from each other.

19 . A method of operating the CMUT of claim 1 comprising:
grounding an outermost of the deflectable membranes, the outermost deflectable being defined as the deflectable membrane contactable by an object external to the CMUT; and
applying a DC biasing voltage and an AC driving voltage to at least one other deflectable membrane.

20 . An imaging transducer comprising an array of a plurality of the CMUT of claim 1 .

21 . (canceled)

Assignees

• Univ Manitoba

Inventors

• Emadi Tahereh Arezoo
• Buchanan Douglas A

Classifications

• G01H11/06

  by electric means · CPC title

• G01D5/2417

  by varying separation · CPC title

• B06B1/0292 Primary

  Electrostatic transducers, e.g. electret-type · CPC title

• A61B8/4483

  characterised by features of the ultrasound transducer · CPC title