Microphone Membrane And Microphone Comprising The Same

• US 20090129611A1
• Filed: 02/08/2006
• Published: 05/21/2009
• Est. Priority Date: 02/24/2005
• Status: Abandoned Application

• Current Assignee: Epcos AG (TDK Corporation)
• Original Assignee: Epcos AG (TDK Corporation)
• Inventors: Wolff, Ulrich, Pahl, Wolfgang, Leidl, Anton
• Application Number:
  US11/816,960
• Publication Number:
  US 20090129611A1
• Time in Patent Office: Days
• US Class Current: 381/173
• CPC Class Codes: H04R 17/02 Microphones

Abstract

The invention relates to a microphone membrane (M1) comprising two piezoelectric layers (PS1, PS2) with c-axes oriented in the same direction. A first electroconductive surface (E11) is formed in the central metal layer and subjected to a first electrical potential. The piezoelectric layers (PS1, PS2) are respectively arranged between the central metal layer (ML2) and an outer metal layer (ML1, ML3). In a preferred embodiment, the membrane (M1) has a largely symmetrical structure in terms of the layer sequence and the layer thickness thereof.

Claims

1. A microphone membrane comprising:

piezoelectric layers that are stacked; and

a first metal layer among the piezoelectric layers;

wherein axes of the piezoelectric layers are oriented in a the same direction.

2. The microphone membrane of claim 1, further comprising:

a second metal layer and a third metal layer;

wherein the piezoelectric layers between the second and third metal layers.

3. The microphone membrane of claim 1, wherein the microphone membrane has a substantially symmetrical structure in terms of layer sequence and layer thickness;

and

wherein the first metal layer is in a plane of symmetry associated with the substantially symmetrical structure.

4. The microphone membrane of claim 2, wherein the first metal layer comprises a first conductive surface;

and

wherein the first conductive surface is for receiving a first electric potential.

5. The microphone membrane of claim 4, wherein the second metal layer comprises a second conductive surface and the third metal layer comprises third conductive surface;

and

wherein the second conductive surface and the third conductive surface are for receiving a second electrical potential.

6. The microphone membrane of claim 1, wherein the first metal layer comprises a first internal conductive surface for receiving a first electrical potential, and wherein the microphone membrane further comprises:

a second internal conductive surface among the piezoelectric layers

wherein the second internal conductive surface is for receiving a second electrical potential.

7. The microphone membrane of claim 6, wherein a further comprising:

first and second external conductive surfaces, the piezoelectric layers being between the first and second external conductive surfaces;

wherein the first and second external conductive surfaces face the first and second internal conductive surfaces.

8. The microphone membrane of claim 7, wherein the first and second external conductive surfaces are floating.

9. The microphone membrane of claim 7, wherein the first internal conductive surface is in a central region of high potential, and the second internal conductive surface is in a region of high potential that is in an edge region;

or vice versa

wherein the second internal conductive surface is in the central region of high potential, and the first internal conductive surface is in a region of high potential that is in the edge region.

10. The microphone membrane of claim 7, wherein the first internal conductive surface is electrically connected to a first electrode at the first external conductive surface via a first electrical connection;

and

wherein the second internal conductive surface is electrically connected to a second electrode at the second external conductive surface via a second electrical connection.

11. The microphone membrane of claim 1, wherein the first metal layer comprises a first internal conductive surface, and wherein the microphone member further comprises:

a second internal conductive surface,

a first external conductive surface;

a second external conductive surface;

a third external conductive surface; and

a fourth external conductive surface;

wherein the first and second external conductive surfaces are adjacent to a first piezoelectric layer, and the third and fourth external conductive surfaces are adjacent to a second piezoelectric layer;

wherein the first internal conductive surface is between the first external conductive surface and the third external conductive surface; and

wherein the second internal conductive surface is between the second external conductive surface and the fourth external conductive surface.

12. The microphone membrane of claim 11, wherein the first internal conductive surface is for receiving a first electrical potential;

wherein the second and fourth external conductive surfaces are for receiving a second electrical potential; and

wherein the second internal conductive surface is electrically connected to the first and third external conductive surfaces via interlayer contacts in the piezoelectric layers.

13. The microphone membrane of claim 1, wherein the first metal layer comprises a first floating structure;

wherein the microphone membrane further comprises first and second external metal layers, the piezoelectric layers being between the first and second metal layers;

wherein at least one of the first and second external metal layers comprises a second floating structure and a third floating structure, the first floating structure being electrically insulated from the second floating structure;

wherein the second floating structure is opposite a first conductive surface of the microphone membrane and a first portion of the first floating structure; and

wherein the third floating structure is opposite a second conductive surface of the microphone membrane and a second portion of the first floating structure.

14. The microphone membrane of claim 13, wherein the first conductive surface and the second portion of the first floating structure are in a first region of high potential;

and

wherein the second conductive surface and the first portion of the first floating structure are in a second region of high potential.

15. A microphone comprising:

the microphone membrane of claim 1; and

a supporting substrate;

wherein the microphone membrane is mounted above a recess in the supporting substrate.

16. The microphone of claim 15, wherein the microphone membrane is clamped to the supporting substrate on one side only, and wherein an opposite side of the membrane to the one side that is clamped can vibrate upon application of an acoustic signal.

17. The microphone of claim 15, wherein opposite sides of the membrane are fastened to the supporting substrate, and wherein additional opposite ends of the membrane are not fastened to the supporting substrate and can vibrate.

18. A microphone comprising

a supporting substrate having a recess;

and

a membrane mounted above the recess, wherein the membrane is clamped to the supporting substrate on one side of the membrane only, and wherein another side of the membrane can vibrate upon application of an acoustic signal.

20. The microphone of claim 18, wherein the membrane comprises at least one piezoelectric layer.

21. The microphone of claim 18, further comprising:

an elastic support that can vibrate and to which the membrane is connected;

wherein the elastic support extends beyond a free end of the membrane connects the opposite walls of the recess to one another.

22. The microphone of claim 21, wherein the membrane is on the elastic support.

23. The microphone of claim 21, wherein the elastic support runs along an upper side and a lateral surface of the free end of the membrane.

24. The microphone of claim 21, further comprising:

a metal structure connected to the membrane that projects beyond the free end of the membrane and connects the free end and a wall of the recess, wherein the wall is located opposite the free end.

25. The microphone of claim 24, wherein the metal structure is constructed in a lowermost metal layer of the membrane.

26. The microphone of claim 24, wherein the metal structure runs partially in a central or uppermost metal layer of the membrane and along a lateral surface of the free end of the membrane.

19. A microphone comprising:

a supporting substrate having a recess;

a membrane mounted above the recess, wherein different ends of the membrane are fastened to the supporting substrate, and wherein other different ends of the membrane are not fastened to the supporting substrate and can vibrate upon application of an acoustic signal.