Micro electrical mechanical systems pressure sensor
View Patent ↗A micro electrical mechanical system (MEMS) pressure sensor includes a base structure defining an opening, a plurality of support members coupled to the base structure, a thin-film diaphragm supported by the support members, and at least one strain-sensitive member associated with the at least one support member.
1. A micro electrical mechanical system (MEMS) pressure sensing device, comprising:
a base structure, said base structure defining a cavity therein;
a flexible support member spanning said cavity and attached at opposite edges of said cavity;
a diaphragm responsive to pressure, said diaphragm being disposed on said base structure over said flexible support member;
a motion translation support member mechanically coupling said diaphragm and said flexible support member, such that displacement of said diaphragm is translated into displacement of said flexible support member; and
at least one stain-sensitive member configured to detect strain on said flexible support member.
2. The MEMS pressure sensing device of claim 1 , wherein said diaphragm is larger than said flexible support member.
3. The MEMS pressure sensing device of claim 1 , wherein said motion translation support member is disposed at a center of said diaphragm.
4. The MEMS pressure sensing device of claim 1 , wherein said at least one strain-sensitive member is disposed where said flexible support member is attached at an edge of said cavity.
5. The MEMS pressure sensing device of claim 1 , wherein said strain-sensitive member comprises a capactive sensing mechanism.
6. The MEMS pressure sensing device of claim 1 , wherein said flexible support member comprises members attached at four separate edges of said cavity.
7. The MEMS pressure sensing device of claim 1 , wherein said strain-sensitive member measure light reflected from said flexible support member.
8. The MEMS pressure sensing device of claim 1 , wherein said strain-sensitive member comprises at least one piezoresistor.
9. The MEMS pressure sensing device of claim 8 , wherein said strain-sensitive member comprises at least three piezoresistors arranged with two of the piezoresistors being perpendicular to one another and a third piezoresistor disposed at an angle bisecting the angle between the perpendicular piezrosistors
10. The MEMS pressure sensing device of claim 1 , further comprising a Wheatstone bridge including a plurality of resistive members, wherein at least one of said resistive members of said Wheatstone bridge includes said strain-sensitive device.
11. The MEMS pressure sensing device of claim 1 , said diaphragm is supported above said base structure by a plurality of support members.
12. The MEMS pressure sensing device of claim 11 , wherein said at least one strain-sensitive member is integrated in at least one of said plurality of support members.
13. The MEMS pressure sensing device of claim 1 , further comprising a pressure equalizing member configured to equalize pressure on said diaphragm.
14. The MEMS pressure sensing device of claim 13 , wherein said pressure equalizing member comprises one of a serpentine equalizing channel or a valve disposed in an equalizing channel.
15. The MEMS pressure sensing device of claim 1 , wherein said pressure sensing device comprises a microphone.
16. The MEMS pressure sensing device of claim 1 , wherein said diaphragm is disposed at an angle and not parallel to a surface of said base structure comprising said cavity.
17. A micro electrical mechanical system (MEMS) pressure sensing device, comprising:
a base structure, said base structure defining a cavity therein;
a flexible support member spanning said cavity and attached at opposite edges of said cavity;
a diaphragm responsive to pressure, said diaphragm being-disposed on said base structure over said flexible support member;
a motion translation support member mechanically coupling said diaphragm and said flexible support member, such that displacement of said diaphragm is translated into displacement of said flexible support member; and
at least one strain-sensitive member, wherein said at least one strain-sensitive member is disposed on a stress concentration point of said flexible support member.
18. The MEMS pressure sensing device of claim 17 , wherein said strain-sensitive member comprises one of a strain gauge, or piezoresistor.
19. The MEMS pressure sensing device of claim 17 , wherein said strain sensitive member is configured to measure one of an electromagnetic effect an electrostrictive effect, a thermoelectric effect, a piezoelectric effect, a piezoresistive effect, an optoelectric effect, an optical effect, or an capacitive effect of strain on said device.
20. The MEMS pressure sensing device of claim 17 , wherein said stress concentration point occurs where said flexible support member is attached at an edge of said cavity.
21. A method of sensing pressure with a micro electrical mechanical system (MEMS), said method comprising
detecting strain on a flexible support member at a point where strain on said flexible support member is concentrated,
said flexible support member spanning a cavity in a base structure and being attached at opposite edges of said cavity with
a diaphragm responsive to pressure being-disposed on said base structure over said flexible support member and with
a motion translation support member mechanically coupling said diaphragm and said flexible support member such that displacement of said diaphragm is translated into stain on said flexible support member.