Multielement microphone

• US 20060140431A1
• Filed: 12/23/2004
• Published: 06/29/2006
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Zurek, Robert A.
• Granted Patent: US 7,936,894 B2
• Time in Patent Office: Days
• US Class Current: 381/355
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

An improved microphone assembly (128) is provided for porting two microphones (240, 242) of an opposing pair used for beam forming through a single symmetric porting structure (244). The microphone assembly (128) includes a first microphone capsule (240), a second microphone capsule (242) and a porting structure (244). The porting structure (244) encloses the first and second microphone capsules (240, 242) therein and has a first port (251) formed in a first wall (246) thereof and a second port (252) formed in a second wall (248) thereof opposite to the first wall (246), where the first and second microphone capsules (240, 242) share the first port (251).

Claims

1. A microphone assembly comprising:

a first microphone capsule;

a second microphone capsule; and

a porting structure for enclosing the first microphone capsule and the second microphone capsule, the porting structure having a first port formed in a first wall of the porting structure and a second port formed in a second wall of the porting structure opposite to the first wall, wherein the first microphone capsule and the second microphone capsule share the first port.

7. The microphone assembly of claim 1 wherein the porting structure is a symmetric porting structure having the second microphone capsule formed symmetrically with the first microphone capsule, and wherein the first microphone capsule comprises a directional microphone capsule and the second microphone capsule comprises an omnidirectional microphone capsule, and wherein the directional microphone capsule and the omnidirectional microphone capsule share the first port, and wherein the directional microphone capsule utilizes the second port.

2. The microphone assembly of claim I wherein the porting structure is a symmetric porting structure having the second microphone capsule formed symmetrically with the first microphone capsule and wherein the first microphone capsule and the second microphone capsule share the second port.

3. The microphone assembly of claim 2 wherein the first microphone capsule is a directional microphone capsule having a first element axis and the second microphone capsule is a directional microphone capsule having a second element axis and wherein the second element axis is oriented about 180 degrees relative to the first element axis.

4. The microphone assembly of claim 3 wherein the first microphone capsule and the second microphone capsule each comprise a first order directional microphone element.

5. The microphone assembly of claim 4 wherein the first order directional microphone elements are cardioid microphone capsules.

6. The microphone assembly of claim 2 wherein the first microphone capsule and the second microphone capsule are utilized for beam forming.

8. A method for manufacturing a first order directional semiconductor microphone in a semiconductor die comprising the steps of:

forming a gradient microphone in the semiconductor die, the gradient microphone having a rear port; and

forming acoustic resistance at the rear port.

9. The method of claim 8 wherein the step of forming acoustic resistance comprises the step of forming multi-octave, frequency dependant acoustic resistance.

10. The method of claim 8 wherein the step of forming acoustic resistance comprises the step of forming a three-dimensional acoustic labyrinth.

11. The method of claim 10 wherein the step of forming the three-dimensional acoustic labyrinth comprises the step of forming a predetermined three-dimensional acoustic labyrinth pattern having a predetermined frequency dependant acoustic resistance.

12. A microphone array comprising:

a semiconductor die; and

a first microelectro-mechanical system (MEMS) microphone structure defining a directional microphone element formed in the semiconductor die, the first MEMS microphone structure including a first acoustic labyrinth.

13. The microphone array of claim 12 wherein the first MEMS microphone structure further comprises:

a conductive diaphragm overlaying the first acoustic labyrinth and defining a cavity therebetween; and

a conductive backplate formed within the cavity.

14. The microphone array of claim 12 wherein the first MEMS microphone structure has a first axis, the microphone array further comprising:

a first common port;

a second common port defined symmetrically to the first common port; and

a second MEMS microphone structure having a second acoustic labyrinth formed in the semiconductor die and having a second axis, the second axis oriented 180 degrees in relation to the first axis,

wherein the first MEMS microphone structure and the second MEMS microphone structure are acoustically coupled to both the first common port and the second common port.

15. The microphone array of claim 12 wherein the first MEMS microphone structure is a directional microphone structure and has a first axis, the microphone array further comprising:

a common port;

a rear port defined opposite to the common port; and

a second MEMS microphone structure forming an omnidirectional microphone structure in the semiconductor die and having a second axis, the second axis oriented parallel to the first axis,

wherein the first MEMS microphone structure and the second MEMS microphone structure are acoustically coupled to the common port and the first MEMS microphone structure is acoustically coupled to the rear port.

16. An electronic device comprising:

a user interface including a microphone assembly having a first microphone capsule, a second microphone capsule, and a porting structure for enclosing the first microphone capsule and the second microphone capsule, the porting structure having a first port formed in a first wall of the porting structure and a second port formed in a second wall of the porting structure opposite to the first wall, wherein the first microphone capsule and the second microphone capsule share the first port; and

a controller coupled to the user interface for receiving information therefrom and for providing signals to the user interface for operation of the microphone assembly in response thereto.

17. The electronic device of claim 16 wherein the porting structure is a symmetric porting structure having the second microphone capsule formed symmetrically with the first microphone capsule, and wherein the first microphone capsule comprises a directional microphone capsule and the second microphone capsule comprises an omnidirectional microphone, and wherein the directional microphone capsule utilizes the second port.

18. The electronic device of claim 16 wherein the controller receives the information from the directional microphone capsule and the omnidirectional microphone capsule and, in response to said information, detects low wind noise conditions and high wind noise conditions and wherein the controller provides a low wind noise signal to the microphone assembly in response to detecting low wind noise conditions, and wherein the microphone assembly utilizes the directional microphone capsule and the omnidirectional microphone capsule for beam forming and steering to generate the information for providing to the controller in response to the low wind noise signal.

19. The electronic device of claim 18 wherein the controller provides a high wind noise signal to the microphone assembly in response to detecting high wind noise conditions, and wherein the microphone assembly utilizes only the omnidirectional microphone capsule to generate the information for providing to the controller in response to the high wind noise signal.

20. The electronic device of claim 16 further comprising:

an antenna for receiving and transmitting radio frequency (RF) signals;

receiver circuitry coupled to the antenna for demodulating and decoding the RF signals to derive information therefrom;

transmitter circuitry coupled to the antenna for encoding and modulating information into RF signals; and

a controller coupled to the microphone assembly for providing signals thereto and for receiving information to the receiver circuitry for receiving information therefrom and coupled to the transmitter circuitry for providing information thereto.