Apparatus for mounting a sensor having a hermetic seal
Apparatus and Methods for fabricating apparatus having a hermetic seal to seal a portion of an apparatus, for example and without limitation, a portion having a MEMS sensor. One such method uses crimping devices to compress a seal in a cavity formed in a housing that includes a MEMS sensor attached to a stress isolator. Under such compression, the seal deforms to hermetically seal surfaces around the inside, outside and bottom of the stress isolator.
1. An apparatus comprising:
a housing with a top and a bottom and a hole that passes through the housing from the top to the bottom wherein the housing further comprises a first cavity with a first inner wall, a first outer wall and a first cavity bottom and wherein the housing further comprises a second cavity with a second inner wall, a second outer wall and a second cavity bottom and both the first cavity and second cavity extend down into the housing from the top and surround the hole wherein the first outer wall of the first cavity is the second inner wall of the second cavity;
a seal with a toroidal shape and an open top, wherein the seal is located in the first cavity bottom and surrounds the first inner wall;
an isolation member coupled to a sensor and extending down into the first cavity such that the isolation member extends down into the open top of seal; and
a collar coupled to the housing and extending down into the second cavity.
2. The apparatus of claim 1 , wherein the seal is deformed such that it seals the isolation member to the housing.
3. The apparatus of claim 2 wherein the sensor is a pressure sensor.
4. The apparatus of claim 1 , wherein the housing is cylinder shaped.
5. The apparatus of claim 1 , wherein the seal is made from copper.
6. The apparatus of claim 1 , wherein the seal is a copper alloy.
7. The apparatus of claim 1 , wherein the sensor is a MEMS sensor.
8. The apparatus of claim 1 , wherein the collar is made from steel.
9. The apparatus of claim 1 , wherein the housing comprises of one or more of stainless steel, brass and aluminum.
10. The apparatus of claim 1 wherein the collar has a first hole that passes through the collar wherein, the first hole is coaxial with the hole in the housing, first cavity and second cavity.
11. An apparatus having a hermetic seal comprising:
a housing with a top and bottom and a hole that passes through the housing from the top to the bottom wherein the housing further comprises a first cavity that extends down into the housing from the top and surrounds the hole and has a cavity bottom and wherein the housing further comprises a protrusion that surrounds the hole and extends up from the cavity bottom into the first cavity and wherein the housing further comprises a second cavity that extends down into the housing from the top and surrounds, and is coaxial with, the first cavity;
a seal with a toroidal shape with an open top located in the bottom of the first cavity wherein the seal surrounds the protrusion;
an isolation member coupled to a sensor and extending down into the seal through the open top; and
a collar that surrounds the isolation member and is pressed down into the housing and into the second cavity.
12. The apparatus of claim 11 , wherein the toroidal seal covers the bottom of the first cavity.
13. The apparatus of claim 11 , wherein the housing is cylinder shaped.
14. The apparatus of claim 11 , wherein the seal is made from copper.
15. The apparatus of claim 11 , wherein the seal is a copper alloy.
16. The apparatus of claim 11 , wherein the collar is made from steel.
17. The apparatus of claim 11 , wherein the housing comprises of one or more of stainless steel, brass and aluminum.
18. The apparatus of claim 11 , wherein the collar has a first hole that passes through the collar, and wherein the first hole is coaxial with the hole in the housing, first cavity and second cavity.
19. The apparatus of claim 11 , wherein the sensor is a pressure sensor.
20. An apparatus having a hermetic seal comprising:
a housing with a top and bottom and a hole that passes through the housing from the top to the bottom wherein the housing further comprises a first cavity that extends down into the housing from the top and surrounds the hole and has a cavity bottom and wherein the housing further comprises a pipe that surrounds the hole and extends up from the cavity bottom into the first cavity and wherein the housing further comprises a second cavity that extends down into the housing from the top and surrounds, and is coaxial with, the first cavity;
a seal with a toroidal shape with an open top located in the bottom of the first cavity wherein the seal surrounds the pipe;
an isolation member coupled to a sensor and extending down into the seal through the open top; and
a collar that surrounds the isolation member and is pressed down into the housing and into the second cavity.