Support Apparatus for Microphone Diaphragm

• US 20070165888A1
• Filed: 01/22/2007
• Published: 07/19/2007
• Est. Priority Date: 04/25/2005
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Analog Devices, Inc.
• Inventors: Weigold, Jason
• Granted Patent: US 7,885,423 B2
• Time in Patent Office: Days
• US Class Current: 381/174
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81B 3/0037 For increasing stroke, i.e. achieve large displacement of actuated parts
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 2307/201 Damping aspects of the outer suspension of loudspeaker diaphragms by addition of additional damping means
• CPC Class Codes: H04R 2410/00 Microphones
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 7/20 Securing diaphragm or cone resiliently to support by flexible material, springs, cords, or strands

Abstract

A microphone includes a diaphragm assembly supported by a substrate. The diaphragm assembly includes at least one carrier, a diaphragm, and at least one spring coupling the diaphragm to the at least one carrier such that the diaphragm is spaced from the at least one carrier. An insulator (or separate insulators) between the substrate and the at least one carrier electrically isolates the diaphragm and the substrate.

Claims

1. A microphone comprising:

a substrate;

a diaphragm assembly supported by the substrate, the diaphragm assembly including at least one carrier, a diaphragm, and at least one spring coupling the diaphragm to the at least one carrier, the diaphragm being spaced from the at least one carrier; and

at least one insulator between the substrate and the at least one carrier so as to electrically isolate the diaphragm and the substrate.

2. A microphone according to claim 1, wherein the substrate and the diaphragm are capacitively coupled to form a fixed plate and a movable plate of a variable capacitor.

3. A microphone according to claim 1, wherein each carrier is coupled to an insulator and wherein such insulator is coupled to the substrate.

4. A microphone according to claim 1, wherein the diaphragm is perforated.

5. A microphone according to claim 1, wherein the diaphragm is corrugated.

6. A microphone according to claim 1, wherein the diaphragm has a plane when unflexed, the at least one spring producing a space between the diaphragm and the at least one carrier in the direction of the plane of the diaphragm.

7. A microphone according to claim 1, wherein the diaphragm is stress isolated from the at least one carrier.

8. A microphone according to claim 1, wherein the at least one carrier comprises a single unitary carrier surrounding the diaphragm.

9. A microphone according to claim 1, wherein the at least one carrier comprises a plurality of distinct carriers.

10. A microphone according to claim 1, wherein the at least one insulator comprises an oxide.

11. A microphone according to claim 1, wherein the diaphragm assembly comprises polysilicon.

12. A microphone according to claim 1, wherein the at least one insulator is formed directly or indirectly on the substrate.

13. A microphone according to claim 12, wherein the at least one carrier is formed directly or indirectly on the at least one insulator.

14. A microphone according to claim 1, wherein the substrate is formed from a silicon layer of a silicon-on-insulator wafer.

15. A microphone according to claim 1, wherein the substrate includes a number of throughholes.

16. A microphone according to claim 15, wherein the throughholes allow sound waves to reach the diaphragm from a back-side of the substrate.

17. A microphone according to claim 1, further comprising electronic circuitry that produces a signal in response to diaphragm movement.

18. A microphone according to claim 17, wherein the electronic circuitry is formed direct or indirectly on the substrate.

19. A microphone comprising:

a substrate;

a diaphragm;

support means for movably coupling the diaphragm to the substrate, the support means including carrier means for fixed coupling with the substrate and suspension means for movably coupling the diaphragm to the carrier means and spacing the diaphragm from the carrier means; and

insulator means for electrically isolating the diaphragm and the substrate.

20. A microphone according to claim 19, further comprising means for capacitively coupling the substrate and the diaphragm to form a fixed plate and a movable plate of a variable capacitor.

21. A microphone according to claim 19, further comprising means for allowing sound waves to reach the diaphragm from a back-side of the substrate.

22. A microphone according to claim 19, further comprising means for producing a signal in response to diaphragm movement.