Hermetically sealed feedthrough case

• US 8,538,530 B1
• Filed: 11/02/2009
• Issued: 09/17/2013
• Est. Priority Date: 11/19/2008
• Status: Active Grant

• Current Assignee: Advanced Bionics AG (Sonova Holding AG)
• Original Assignee: Advanced Bionics (Sonova Holding AG)
• Inventors: Orinski, William G.
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): MAHMOOD, NADIA AHMAD
• Application Number:
  US12/610,567
• Time in Patent Office: 1,415 Days
• Field of Search: 607/36
• US Class Current: 607/36
• CPC Class Codes: A61N 1/3754 Feedthroughs

Abstract

An implantable medical device includes a housing component comprising a flexure; and a ceramic feedthrough attached to the flexure such that the flexure reduces transmission of forces from housing component to the ceramic feedthrough. According to one illustrative embodiment, the implantable medical device is a cochlear implant which includes a titanium feedthrough case made up of a body portion and a flexure; and a ceramic feedthrough being hermetically joined to the flexure by an active braze, the flexure reducing transmission of forces from the titanium feedthrough case to the ceramic feedthrough.

Claims

1. An implantable medical device comprising:

a hermetically sealed housing comprising;

an interior cavity configured to receive electronics;

a single piece metal housing component surrounding said electronics, said single piece metal housing component comprising;

a structural body portion; and

a flexure extending from said structural body portion, wherein said structural body portion and said flexure are integral elements of said single piece metal housing component;

a ceramic feedthrough attached to said flexure; and

a conductor passing through said ceramic feedthrough, wherein said sealed housing extends above and below said conductor, wherein extension of said sealed housing above and below said conductor protects said conductor from direct force applied to a top surface and a bottom surface of said sealed housing, and wherein said flexure reduces transmission of said force from said structural body portion to said ceramic feedthrough.

2. The implantable medical device of claim 1, wherein said housing component is made from one of:

titanium and titanium alloy.

3. The implantable medical device of claim 1, wherein said flexure reduces said transmission of force in a radial direction and said transmission of force along an axis perpendicular to said radial direction.

4. The implantable medical device of claim 1, wherein said flexure comprises:

a first portion, said first portion extending from said body portion in a first direction; and

a second portion, said second portion extending from said first portion in a direction that is substantially perpendicular to said first direction.

5. The implantable medical device of claim 4, wherein said ceramic feedthrough comprises a planar bottom surface and a curved perimeter surface, wherein an outer perimeter of said planar bottom surface of said ceramic feedthrough is hermetically joined to said second portion such that a gap is interposed between said curved perimeter surface of said ceramic feedthrough and said first portion.

6. The implantable medical device of claim 5, wherein said gap is between 1/50^th and 1/100^th of a largest dimension of said ceramic feedthrough.

7. The implantable medical device of claim 4, further comprising a relief cutout in said flexure at an intersection of said first portion and said second portion.

8. The implantable medical device of claim 1, wherein said ceramic feedthrough comprises a multilayer ceramic structure having a plurality of vias and interlayers connecting said vias to create said conductor between a first planar surface of said ceramic feedthrough and an opposing second planar surface of said ceramic feedthrough.

9. The implantable medical device of claim 8, wherein said conductor further comprises bonding pads disposed on said first planar surface and said opposing second planar surface, electronic components bonded to said bonding pads disposed on said first surface, and wires bonded to bonding pads disposed on said second surface.

10. The implantable medical device of claim 1, further comprising an active braze joint, wherein said ceramic feedthrough is directly bonded to said flexure by said active braze joint such that said ceramic feedthrough is hermetically joined to said flexure.

11. The implantable medical device of claim 10, wherein said active braze joint comprises titanium.

12. The implantable medical device of claim 10, wherein a preformed braze ring is sandwiched between said ceramic feedthrough and said flexure, said preformed braze ring reacting with said ceramic feedthrough and bonding with said flexure to form said active braze joint between said feedthrough and said flexure.

16. The implantable medical device of claim 10, wherein said active braze joint comprises titanium, nickel, and ceramic particulates, said titanium reacting with said ceramic feedthrough to form a reaction layer that reduces interfacial energy between said active braze joint and said ceramic feedthrough.

13. A cochlear implant comprising:

a single piece titanium feedthrough case comprising;

a body portion;

a first portion, said first portion extending from said body portion in a first direction; and

a second portion, said second portion extending from said first portion in a direction that is substantially perpendicular to said first direction, said first portion and said second portion comprising a flexure, wherein said body portion, said first portion, and said second portion are integral elements of said single piece titanium feedthrough case; and

a ceramic feedthrough wherein a first surface of said ceramic feedthrough is directly joined to said second portion by an active braze, said flexure reducing transmission of forces from said titanium feedthrough case to said ceramic feedthrough.

14. The cochlear implant of claim 13, wherein said ceramic feedthrough is hermetically joined to said second portion to form a gap between an inside perimeter surface of said body portion and an outer perimeter of said ceramic feedthrough;

said gap between 1/50^th and 1/100^th of a largest dimension of said ceramic feedthrough.

15. The cochlear implant of claim 13, further comprising:

a titanium top cover;

said titanium top cover being hermetically joined to said titanium feedthrough case using laser welding;

a titanium bottom cover;

said titanium bottom cover being joined to said titanium feedthrough case using laser welding; and

a silicone overcoat, said silicone overcoat being applied using a liquid injection molding process such that said silicone overcoat substantially encapsulates said cochlear implant.

17. The cochlear implant of claim 13, wherein a relief cutout is formed at an intersection of said first portion and said second portion, said relief cutout increasing flexibility of said flexure and localizing bending in said flexure.

18. A hermetic housing for an implanted medical device, said hermetic housing comprising:

a housing component defining an outer perimeter of said hermetic housing, said metal feedthrough housing component comprising;

a first structural portion;

a second portion extending inwardly from said first structural portion, wherein said first structural portion and second portion are integral elements of said housing component; and

a relief cutout in said second portion to form a thin cross section flexure;

a ceramic body joined to said second portion;

a cover joined to the housing component to form a cavity; and

a conductor passing through said ceramic body, wherein a first end of the conductor is exposed inside the cavity and said housing component extends beyond a second end of said conductor so as to protect said conductor from application of direct force applied to a top surface and a bottom surface of said hermetic housing.

19. The housing of claim 18, wherein said ceramic body is directly joined to said second portion of said single piece metal housing component by a braze joint, and wherein said thin cross section flexure reduces transmission of said force from said structural portion to said ceramic body and conductor.