MEMS structure with adjustable ventilation openings
A MEMS structure includes a backplate, a membrane, and an adjustable ventilation opening configured to reduce a pressure difference between a first space contacting the membrane and a second space contacting an opposite side of the membrane. The adjustable ventilation opening is passively actuated as a function of the pressure difference between the first space and the second space.
1. A MEMS structure comprising:
a backplate;
a membrane spaced a gap distance from the backplate; and
an adjustable ventilation opening configured to reduce a pressure difference between a first space contacting a first side of the membrane and a second space contacting an opposite second side of the membrane, wherein the adjustable ventilation opening is passively actuated as a function of the pressure difference between the first space and the second space.
2. The MEMS structure according to claim 1 , wherein the adjustable ventilation opening is located on the membrane.
3. The MEMS structure according to claim 2 , wherein the adjustable ventilation opening is located on the membrane in a region near an edge and adjacent to a backplate window.
4. The MEMS structure according to claim 2 , wherein the adjustable ventilation opening is thinner than another portion of the membrane.
5. The MEMS structure according to claim 1 , wherein the adjustable ventilation opening is located on the backplate.
6. The MEMS structure according to claim 1 , wherein the backplate is mechanically connected to a substrate and the adjustable ventilation opening is located on the substrate.
7. The MEMS structure according to claim 1 , wherein the backplate is mechanically connected to a substrate and the substrate is mechanically connected to a support structure, the adjustable ventilation opening being located on the support structure.
8. The MEMS structure according to claim 1 , wherein the first space is enclosed within a device housing and the adjustable ventilation opening is located on the device housing.
9. The MEMS structure according to claim 1 , wherein the adjustable ventilation opening comprises a cantilever.
10. The MEMS structure according to claim 1 , wherein the adjustable ventilation opening is one of a plurality of adjustable ventilation openings.
11. A MEMS structure comprising:
a backplate;
a membrane spaced a gap distance from the backplate; and
an adjustable ventilation opening comprising a cantilever on the membrane, the adjustable ventilation opening configured to reduce a pressure difference between a first space contacting the membrane and a second space contacting an opposite side of the membrane.
12. The MEMS structure according to claim 11 , wherein the adjustable ventilation opening is passively actuated as a function of the pressure difference between the first space and the second space.
13. The MEMS structure according to claim 11 , wherein the cantilever includes a tip that deflects away from a plane of the membrane by a distance that is more than four times the gap distance.
14. The MEMS structure according to claim 11 , wherein the gap distance is less than 3 μm.
15. The MEMS structure according to claim 14 , wherein the cantilever has a length between 10 μm and 150 μm.
16. The MEMS structure according to claim 11 , wherein a ratio of a length of the cantilever to the gap distance is greater than 3.
17. The MEMS structure according to claim 11 , wherein the cantilever is located on the membrane in a region near an edge and adjacent to a backplate window.
18. The MEMS structure according to claim 11 , wherein the cantilever is thinner than another portion of the membrane.
19. The MEMS structure according to claim 11 , wherein the cantilever is separated from remaining portions of the membrane by a U-shaped gap.
20. The MEMS structure according to claim 19 , wherein the adjustable ventilation opening comprises a square-shaped flexible structure.
21. The MEMS structure according to claim 19 , wherein the U-shaped gap includes opening portions extending away from top portions of the gap.
22. The MEMS structure according to claim 21 , wherein the adjustable ventilation opening comprises curved openings the top portions of the gap.
23. The MEMS structure according to claim 11 , wherein the adjustable ventilation opening comprise intertwining flexible structures separated by a serpentine opening gap.
24. The MEMS structure according to claim 11 , wherein the adjustable ventilation opening comprises two flexible structures, each separated from remaining portions of the membrane by a U-shaped gap, wherein the two flexible structures extend in opposite directions.
25. The MEMS structure according to claim 11 , wherein the cantilever is surrounded by a spring-shaped gap such that at least two portions of the gap are adjacent a region of the cantilever.
26. A MEMS device comprising:
a MEMS structure comprising a backplate and a membrane spaced a gap distance from the backplate;
a housing enclosing the MEMS structure;
a sound port acoustically coupled to the membrane; and
an adjustable ventilation opening in the housing configured to reduce a pressure difference between a first space contacting the membrane and a second space,
wherein the adjustable ventilation opening is passively actuated as a function of the pressure difference between the first space and the second space.
27. The device according to claim 26 , wherein the adjustable ventilation opening comprises a cantilever.
28. The device according to claim 26 , wherein the housing comprises a lid and the adjustable ventilation opening is in the lid.
29. The device according to claim 26 , wherein the housing comprises a substrate and the adjustable ventilation opening is in the substrate.
30. The device according to claim 26 , wherein the housing comprises a printed circuit board and the adjustable ventilation opening is in the printed circuit board.