Electromagnetically coupled hermetic chamber

• US 20060241354A1
• Filed: 04/12/2006
• Published: 10/26/2006
• Est. Priority Date: 04/12/2005
• Status: Active Grant

• Current Assignee: St. Jude Medical Luxembourg Holdings Ii S.A.R.L.
• Original Assignee: CardioMEMS Incorporated
• Inventors: Allen, Mark G.
• Granted Patent: US 8,025,625 B2
• Time in Patent Office: Days
• US Class Current: 600/300
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/03 Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs A61B5/205 takes precedence

Abstract

An electromagnetically coupled hermetic chamber includes a body defining a hermetic chamber. A first conductive structure is disposed within the hermetic chamber, and a second conductive structure is attached to the body outside of the hermetic chamber. The first conductive structure is electromagnetically coupled to the second conductive structure without direct electrical paths connecting the first and second conductive structures. Thus the first conductive structure can be coupled to external electronics without the need for electrical feedthroughs or vias that could compromise the integrity of the hermetic chamber.

Claims

1. An apparatus comprising:

a body defining a hermetic chamber;

a first conductive structure disposed within said chamber; and

a second conductive structure attached to said body outside of said chamber;

wherein said first conductive structure is electromagnetically coupled to said second conductive structure without direct electrical paths connecting said first and second conductive structures.

2. The hermetic chamber of claim 1, further comprising means responsive to a change in an environmental parameter for varying the geometry of the hermetic chamber, whereby the electrical characteristics of said first conductive structure are altered.

3. A sensor for indicating a physical state within a patient, comprising:

a sensor body defining a hermetic chamber;

a first conductive structure disposed within said hermetic chamber and having an element providing an inductance;

a second conductive structure disposed outside said chamber and located in proximity to said first structure;

means operatively associated with said hermetic chamber for isolating at least a major portion of said second conductive structure from the ambient; and

means for connecting said second structure to remote electronics disposed outside of said sensor body;

wherein there are no direct electrical paths connecting said first structure disposed within said hermetic chamber to said second structure disposed outside said hermetic chamber; and

whereby said second structure can be excited using time-varying electrical excitation via said remote electronics and, subsequently, electromagnetically coupled to said structure disposed within said chamber.

4. The sensor of claim 3, wherein said first and second conductive structures comprise a capacitor.

5. The sensor of claim 3, wherein said first and second conductive structures comprise inductors.

6. The sensor of claim 3, wherein said body comprises ceramic material.

7. The sensor of claim 6, wherein said ceramic material is selected from the group consisting of glass, fused silica, sapphire, quartz, and silicon.

8. The sensor of claim 7, wherein said body comprises fused silica.

9. The sensor of claim 3,

wherein a portion of said sensor body defining said hermetic chamber comprises a deflective region deflectable in response to a physiologically relevant pressure;

and

wherein at least a portion of said first conductive structure is coupled to said deflective region.

10. The sensor of claim 3, wherein said first conductive structure disposed within said hermetic chamber provides a capacitance and an inductance.

11. The sensor of claim 3, wherein said first conductive structure further comprises:

a first element providing an inductance; and

a second element providing a capacitance, said first and second elements being electrically connected.

12. The sensor of claim 3, wherein said means for isolating at least a major portion of said second conductive structure from the ambient comprises a coating.

13. The sensor of claim 3, wherein said coating is selected from the group consisting of polyimide, liquid crystal polymer (LCP), urethane, polyester, teflon, FEP, PTFE, polyamide and silicone rubber

14. The sensor of claim 13, wherein said coating comprises silicone rubber.

15. The sensor of claim 3, wherein said means for connecting said second structure to remote electronics disposed outside of said hermetic chamber comprises wires connected to said second structure and extending through said means for isolating said second conductive structure from the ambient.

16. The sensor of claim 3, wherein said means for isolating at least a major portion of said second conductive structure from the ambient comprises ceramic material.

17. The sensor of claim 16, wherein said ceramic material is selected from the group consisting of glass, fused silica, sapphire, quartz, and silicon.

18. The sensor of claim 17, wherein said ceramic material is fused silica.

19. The sensor of claim 16, wherein said means for connecting said second structure to remote electronics comprises electrical feedthroughs disposed across said isolating means and coupled to said second structure.

20. The sensor of claim 3, wherein said conductive structure is further connected to an integrated circuit.

21. The sensor of claim 3, wherein said means for isolating at least a major portion of said second conductive structure from the ambient comprises a second chamber defined by said sensor body.

22. The sensor of claim 21, wherein said integrated circuit is further coupled to electrical feedthroughs communicating between said second chamber and the ambient.

23. An electromagnetically coupled hermetic chamber, comprising:

a body defining a hermetic chamber;

an absorbing structure disposed within said hermetic chamber; and

an emissive structure disposed outside of said hermetic chamber and mechanically coupled to said hermetic chamber;

wherein said absorbing structure is capable of being energized by said emissive structure without direct electrical paths connecting said first and second structures.