Monolithic micromachined piezoelectric acoustic transducer and transducer array and method of making same

• US 5,956,292 A
• Filed: 09/16/1997
• Issued: 09/21/1999
• Est. Priority Date: 04/13/1995
• Status: Expired due to Term

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Bernstein, Jonathan J.
• Primary Examiner(s): ELDRED, JOHN W
• Application Number:
  US08/931,226
• Time in Patent Office: 735 Days
• Field of Search: 310/324, 310/334, 367/140, 367/174, 367/180, 367/163, 29/25.35
• US Class Current: 367/140
• CPC Class Codes: H04R 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00
• CPC Class Codes: H04R 17/08 signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit includes a support member; a piezoelectric medium disposed on the support member; first and second electrodes engaging the piezoelectric medium; and a control circuit monolithically integrated with the piezoelectric medium and electrodes on the support member and including a switching circuit for selectively interconnecting the electrodes with an I/O bus and a signal processing circuit for conditioning signals propagating between the electrodes and the I/O bus; an array of such acoustic transducers that form an acoustic retina; and a method of making such transducers and arrays.

Claims

1. A monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit, comprising:

a support member, wherein said support member includes a flexible membrane for concentrating acoustic energy and wherein said flexible membrane includes at least one peripheral slot for increasing its flexibility;

a piezoelectric medium disposed on said support member;

first and second electrodes engaging said piezoelectric medium; and

a control circuit monolithically integrated with said piezoelectric medium and electrodes on said support member and including a switching circuit for selectively interconnecting said electrodes with an I/O bus and a signal processing circuit for conditioning signals propagating between said electrodes and I/O bus.

5. The monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit of claim 1 wherein said support member includes a backside cavity on the opposite face from said piezoelectric medium to allow sensing of acoustic energy from either side of the transducer.

8. The monolithic micromechanical piezoelectriz acoustic transducer with integrated control circuit of claim 1 in which said flexible membrane includes first and second vanes cantilevered from a central portion containing said piezoelectric medium.

9. The monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit of claim 1 in which said flexible membrane includes a plurality of spring regions and a plurality of piezoelectric membranes and electrodes disposed one at each of said spring regions.

2. A monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit, comprising:

a support member;

a piezoelectric medium disposed on said support member;

first and second electrodes engaging said piezoelectric medium;

a control circuit monolithically integrated with said piezoelectric medium and electrodes on said support member and including a switching circuit for selectively interconnecting said electrodes with an I/O bus and a signal processing circuit for conditioning signals propagating between said electrodes and I/O bus; and

wherein said support member includes an insulator layer and a backside cavity on the opposite face from said piezoelectric medium to allow sensing of acoustic energy from either side of the transducer.

3. A monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit, comprising:

a support member;

a piezoelectric medium disposed on said support member;

first and second electrodes engaging said piezoelectric medium;

a control circuit monolithically integrated with said piezoelectric medium and electrodes on said support member and including a switching circuit for selectively interconnecting said electrodes with an I/O bus and a signal processing circuit for conditioning signals propagating between said electrodes and I/O bus; and

wherein said support member includes a flexible membrane for concentrating acoustic energy, in which said flexible membrane includes first and second vanes cantilevered from a central portion containing said piezoelectric medium.

6. The monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit of claim 3 wherein said support member includes a backside cavity on the opposite face from said piezoelectric medium to allow sensing of acoustic energy from either side of the transducer.

4. A monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit, comprising:

a support member;

a piezoelectric medium disposed on said support member;

first and second electrodes engaging said piezoelectric medium;

a control circuit monolithically integrated with said piezoelectric medium and electrodes on said support member and including a switching circuit for selectively interconnecting said electrodes with an I/O bus and a signal processing circuit for conditioning signals propagating between said electrodes and I/O bus; and

wherein said support member includes a flexible membrane for concentrating acoustic energy, in which said flexible membrane includes a plurality of spring regions and a plurality of piezoelectric membranes and electrodes disposed one at each of said spring regions.

7. The monolithic micromechanical piezoelectric acoustic transducer with integrated control circuit of claim 4 wherein said support member includes a backside cavity on the opposite face from said piezoelectric medium to allow sensing of acoustic energy from either side of the transducer.