Micro-electro-mechanical transducers

• US 8,952,595 B2
• Filed: 08/07/2012
• Issued: 02/10/2015
• Est. Priority Date: 05/18/2005
• Status: Active Grant

• Current Assignee: Kolo Medical, Ltd.
• Original Assignee: Kolo Technologies, Inc.
• Inventors: Huang, Yongli
• Primary Examiner(s): Mullins, Burton
• Assistant Examiner(s): Johnson, Eric
• Application Number:
  US13/568,697
• Publication Number:
  US 20120299439A1
• Time in Patent Office: 917 Days
• Field of Search: 310/309, 367/181, 367/163, 600/459, 600/437, 735/143.2, 381/191, 381/174
• US Class Current: 310/309
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 29/49005 Acoustic transducer

Abstract

Some examples include at least one capacitive micro-electro-mechanical transducer (cMUT). For instance, the cMUT may include a substrate, a plate, and a resilient structure therebetween. In some examples, an integrated circuit may be formed on or integrated with the plate or other portion of the cMUT. Furthermore, in some examples, two cMUTs may be arranged in a stacked configuration. For instance, one cMUT may be operable for transmission, while a second cMUT may be operable for reception.

Claims

1. A device comprising:

a first capacitive micromachined ultrasonic transducer (cMUT) having at least one first cMUT cell including a first electrode and a second electrode separated by a first gap; and

a second cMUT including a plurality of second cMUT cells disposed side-by-side over the first cMUT cell, the plurality of second cMUT cells including the second electrode and a third electrode separated by a second gap, wherein

the second electrode is a common electrode for the first cMUT cell and the plurality of second cMUT cells.

2. The device according to claim 1, wherein at least the first cMUT includes at least one integrated circuit formed on at least one surface of the first cMUT cell.

3. The device according to claim 1, wherein the first cMUT comprises:

one or more first supports, wherein the second electrode is separated from the first electrode by the first gap maintained by the one or more first supports; and

a spring member for enabling the first electrode and the second electrode to move toward and away from each other due to the first gap.

4. The device according to claim 3, wherein the second cMUT comprises one or more second supports, wherein the second electrode and the third electrode are separated by the second gap on the opposite side of the second electrode from the first electrode, the second gap being maintained by the one or more second supports.

5. The device according to claim 4, wherein the third electrode is associated with a flexible element that enables the third electrode to move toward and away from the second electrode due to the second gap.

6. The device according to claim 1, wherein the first cMUT transmits ultrasonic energy in at least one first wavelength and the second cMUT receives ultrasonic energy in at least one second wavelength.

7. The device according to claim 1, wherein the first cMUT and the second cMUT are operable separately from one another.

8. The device according to claim 1, wherein:

the second cMUT is connected to a reception circuit to receive acoustic energy; and

the first cMUT is connected to a transmission circuit to transmit acoustic energy.

9. The device according to claim 1, wherein the common electrode shared by the first cMUT cell and the plurality of second cMUT cells is connected to at least one of a bias circuit or a voltage source.

10. The device according to claim 1, further comprising:

a moveable top plate supporting the second electrode and the plurality of second cMUT cells; and

at least one integrated circuit formed on the movable top plate.

11. The device according to claim 1, wherein the plurality of second cMUT cells comprise a plurality of separate transducing spaces separated from each other by supports so that multiple separate transducing spaces of the second cMUT cells wholly overlie a single transducing space of the first cMUT cell.

12. A device comprising:

a first capacitive micromachined ultrasonic transducer (cMUT) cell that includes;

a first electrode;

a second electrode separated from the first electrode by a first gap;

a spring member and one or more first supports for maintaining the first gap between the first electrode and the second electrode, wherein the first electrode and the second electrode are able to move toward and away from each other by flexing of the spring member; and

a plurality of second cMUT cells disposed side-by-side on an opposite side of the second electrode from the first electrode, the plurality of second cMUT cells including the second electrode and a third electrode separated from the second electrode by a second gap, wherein the second electrode serves as a common electrode to the first cMUT cell and the plurality of second cMUT cells.

13. The device according to claim 12, wherein:

the second electrode is a plate or is located on a plate;

the plurality of second cMUT cells are disposed on the plate and include the third electrode contiguous with a flexible element that is separated from the plate by one or more second supports; and

the flexible element enables the third electrode to move toward and away from the second electrode.

14. The device according to claim 12, wherein the plurality of second cMUT cells comprise a plurality of separate transducing spaces separated from each other by second supports so that multiple separate transducing spaces of the second cMUT cells wholly overlie a single transducing space of the first cMUT cell.

15. The device according to claim 12, further comprising an integrated circuit formed on a surface of the first cMUT cell.

16. The device according to claim 12, wherein the second electrode is connected to at least one of a bias circuit or a voltage source.

17. The device according to claim 12, wherein the second electrode is connected to a bias to shield from coupling between a transmission signal transmitted by the first cMUT cell and a reception signal received by the plurality of second cMUT cells.

18. A device comprising:

a first capacitive micromachined ultrasonic transducer (cMUT) cell that includes;

a substrate, wherein a first electrode is associated with the substrate;

a plate disposed above the substrate, wherein a second electrode is associated with the plate; and

a spring member to enable movement of the plate toward and away from the substrate; and

a plurality of second cMUT cells disposed on the plate, the plurality of second cMUT cells comprising the second electrode and at least one third electrode, wherein the second electrode is an upper electrode for the first cMUT cell and a lower electrode for the plurality of second cMUT cells.

19. The device according to claim 18, wherein one or more integrated circuits are formed on the plate.

20. The device according to claim 18, wherein at least one of:

the plate is conductive, at least in part, to serve as the second electrode;

or

the plate includes a conductive layer disposed on the plate to serve as the second electrode.

21. The device according to claim 18, wherein at least one of:

the substrate is conductive, at least in part, to serve as the first electrode;

or

the substrate includes a conductive layer disposed on the substrate to serve, at least in part, as the first electrode.

22. The device according to claim 18, further comprising:

an integrated circuit formed on the plate; and

an electrode layer on the plate overlying at least a portion of the integrated circuit, the electrode layer serving, at least in part, as the second electrode.

23. The device according to claim 18, wherein

the plurality of second cMUT cells are operable separately from the first cMUT cell.

24. The device according to claim 18, wherein individual second cMUT cells have a width that is smaller than a width of the first cMUT cell so that multiple second cMUT cells wholly overlie the first cMUT cell.

25. The device according to claim 18, further comprising:

a flexible element supported away from the plate on a side of the plate opposite to the substrate wherein the third electrode is associated with the flexible element.