Internally grounded flat through filter with hermetically sealed insulative body with internal ground plates

• US 8,868,189 B2
• Filed: 04/30/2013
• Issued: 10/21/2014
• Est. Priority Date: 03/20/2008
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Stevenson, Robert A., Frysz, Christine A., Dabney, Warren S., Johnson, Robert Shawn
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): Bays, Pamela M
• Application Number:
  US13/873,832
• Publication Number:
  US 20130235550A1
• Time in Patent Office: 539 Days
• Field of Search: 607/2, 607/36, 607/37, 607/115, 607/116, 607/119, 361/818
• US Class Current: 607/36
• CPC Class Codes: A61N 1/08 Arrangements or circuits for monitoring, protecting, controlling or indicating for external stimulators A61N1/3603; for implantable neurostimulators A61N1/36128; for heart stimulators A61N1/37; for defibrillators A61N1/3925
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 4/06 Solid dielectrics
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors
• CPC Class Codes: H01G 4/40 Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01R 13/7195 with planar filters with openings for contacts
• CPC Class Codes: H03H 1/0007 of radio frequency interference filters
• CPC Class Codes: H03H 2001/0042 Wound, ring or feed-through type capacitor
• CPC Class Codes: H03H 2001/0085 Multilayer, e.g. LTCC, HTCC, green sheets
• CPC Class Codes: H03H 7/1766 Parallel LC in series path H03H7/1783 takes precedence
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/10015 Non-printed capacitor
• CPC Class Codes: H05K 5/0095 hermetically-sealed
• CPC Class Codes: H05K 9/00 Screening of apparatus or components against electric or magnetic fields devices for absorbing radiation from an antenna H01Q17/00

Abstract

A shielded three-terminal flat-through EMI/energy dissipating filter includes an active electrode plate through which a circuit current passes between a first terminal and a second terminal, a first shield plate on a first side of the active electrode plate, and a second shield plate on a second side of the active electrode plate opposite the first shield plate. The first and second shield plates are conductively coupled to a grounded third terminal. In preferred embodiments, the active electrode plate and the shield plates are at least partially disposed with a hybrid flat-through substrate that may include a flex cable section, a rigid cable section, or both.

Claims

1. A shielded three-terminal flat-through filter hermetic terminal assembly for an active implantable medical device (AIMD), the shielded three-terminal flat-through filter hermetic terminal, assembly comprising:

a) a shielded three-terminal flat-through filter, comprising;

i) a dielectric body having an outer dielectric sidewall providing a dielectric thickness extending from a first dielectric surface spaced from a second dielectric surface, wherein the dielectric body comprises at least one active dielectric via hole and at least one ground dielectric via hole, and wherein both the active and ground dielectric via holes extend through the second dielectric surface and at least part-way into the dielectric thickness;

ii) at least one active lead wire configured for carrying an electrical current and supported in the at least one active dielectric via hole;

iii) at least one ground wire supported in the at least one ground dielectric via hole;

iv) at least one active electrode plate supported by the dielectric body, wherein a first active end of the at least one active electrode plate is conductively coupled to the active lead wire in the active dielectric via hole and a second active end of the active electrode plate is electrically connectable to an electronic circuit of the AIMD;

v) at least one first shield plate supported by the dielectric body on a first side of and spaced from the at least one active electrode plate, wherein the first shield plate is in a non-conductive relationship with the at least one active lead wire;

vi) at least one second shield plate supported by the first dielectric body on a second side of and spaced from the at least one active electrode plate, wherein the second shield plate is in a non-conductive relationship with the at least one active lead wire; and

vii) wherein the at least one first shield plate and the at least one second shield plate are both conductively coupled to the ground wire; and

b) a hermetic terminal comprising;

i) an insulator body having an outer insulator sidewall providing an insulator thickness extending from a first insulator surface spaced from a second insulator surface, wherein at least one active insulator via hole extends through the insulator body from the first insulator surface to the second insulator surface and wherein at least one ground insulator via hole extends through the first insulator surface and at least part-way into the insulator thickness;

ii) at least one ground electrode plate disposed within the insulator body, and

iii) wherein the at least one ground wire supported in the at least one ground dielectric via hole extends at least part-way into the at least one ground insulator via hole, and

iv) wherein the at least one ground electrode plate is conductively coupled to the ground wire and to a ferrule or the AIMD housing, and

c) wherein the shielded three-terminal flat-through filter is disposed adjacent to the hermetic terminal with the second dielectric surface adjacent to the first insulator surface, and

d) wherein the at least one active lead wire supported in the at least one dielectric via hole extends through the at least one active insulator via hole so that a first end of the active lead wire is spaced from the second insulator surface.

2. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein an insulative washer is disposed between the shielded three-terminal flat-through filter and the hermetic terminal.

3. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein the at least one ground electrode plate disposed within the insulator body is conductively coupled to the ferrule or the AIMD housing by a first metallization.

4. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein the feedthrough filter is mounted directly onto at least a portion of the insulator body.

5. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein the at least one active electrode plate comprises a plurality of active electrode plates.

6. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 5, wherein a plurality of lead wires supported by the dielectric body extend through the at least one first and second shield plates in a non-conductive relation therewith.

7. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 6, wherein each lead wire of the plurality of lead wires is conductively coupled to a separate and distinct respective active electrode plate from the plurality of active electrode plates.

8. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein a first conductive pad is conductively coupled to the at least one lead wire at the first dielectric surface, opposite the insulator body, and wherein a second conductive pad is conductively coupled to the second active end of the active electrode plate.

9. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 8, wherein the first and second conductive pads comprise wire bond pads.

10. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein at least one inductor is coupled in series along the length of the at least one active electrode plate so that the circuit current must pass through the at least one inductor.

11. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 10 wherein the at least one inductor in series with the at least one active electrode plate, and at least one of the first and second shield plates are configured to form at least one passive electronic low-pass filter selected from the group consisting of an “

L”

filter, a “

n”

filter, a “

T”

filter, an “

LL”

filter, a “

5 element”

filter, and an “

n”

element filter.

12. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 10 wherein the at least one inductor in series with the at least one active electrode plate, and at least one of the first and second shield plates are configured to form part of a bandstop filter or an L-C trap filter and wherein the bandstop filter or an L-C trap filter is configured to be resonant at an MRI frequency.

13. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein at least one monolithic chip capacitor (MLCC) is conductively coupled between the at least one active electrode plate and either the at least one first shield plate or the at least one second shield plate.

14. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1, wherein the shielded three-terminal flat-through filter is biocompatible and configured for exposure to body fluids.

15. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1 wherein a second metallization contacts the outer dielectric sidewall.

16. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1 wherein at least one second active lead wire is electrically coupled to the second active end of the active electrode plate, the second active lead wire being electrically connectable to electronic circuits of the AIMD.

17. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 1 wherein the surface area of the at least one active electrode plate is maximized to increase parasitic capacitance to a minimum of 20 pf and minimize resistance to current flow.

18. A shielded three-terminal flat-through filter hermetic terminal assembly for an active implantable medical device (AIMD), the shielded three-terminal flat-through filter hermetic terminal assembly comprising:

a) a shielded three-terminal flat-through filter feedthrough filter, comprising;

i) a dielectric body having an outer dielectric sidewall providing a dielectric thickness extending from a first dielectric surface spaced from a second dielectric surface, wherein the dielectric body comprises at least two active dielectric via holes and at least one ground dielectric via hole, and wherein the active and ground dielectric via holes extend through the second dielectric surface and at least part-way into the dielectric thickness;

ii) a first metallization contacting the outer dielectric sidewall;

iii) at least two active lead wires supported in respective ones of the at least two active dielectric via holes;

iv) at least one ground wire supported in the at least one ground dielectric via hole;

v) at least two active electrode plates configured for carrying an electrical current and supported by the dielectric body, wherein a first active end of a first one of the active electrode plates is conductively coupled to a first one of the active lead wires in a first one of the active dielectric via holes, and wherein a first active end of a second one of the active electrode plates is conductively coupled to a second one of the active lead wires in a second one of the active dielectric via holes, and wherein respective second active ends of the at least two active electrode plates are electrically connectable to an electronic circuit of the AIMD;

vi) at least one first shield plate supported by the dielectric body on a first side of and spaced from the at least two active electrode plates, wherein the first shield plate is in a non-conductive relationship with the at least two active lead wires;

vii) at least one second shield plate supported by the first dielectric body on a second side of and spaced from the at least two active electrode plates, wherein the second shield plate is in a non-conductive relationship with the at least two active lead wires; and

viii) wherein the at least one first shield plate and the at least one second shield plate are both conductively coupled to the ground wire; and

b) a hermetic terminal comprising;

i) an insulator body having an outer insulator sidewall providing an insulator thickness extending from a first insulator surface spaced from a second insulator surface, wherein at least two active insulator via holes extend through the insulator body from the first insulator surface to the second insulator surface and wherein at least one ground insulator via hole extends through the first insulator surface and at least part-way into the insulator thickness;

ii) at least one ground electrode plate disposed within the insulator body, and

iii) wherein the at least one ground wire supported in the at least one ground dielectric via hole extends at least part-way into the at least one ground insulator via hole, and

iv) wherein the at least one ground electrode plate is conductively coupled to the ground wire and to a ferrule or the AIMD housing, and

c) wherein the shielded three-terminal flat-through filter is disposed adjacent to the hermetic terminal with the second dielectric surface adjacent to the first insulator surface, and

d) wherein the at least two active lead wires supported in the respective at least two dielectric via holes extend through the at least two active insulator via holes so that respective first ends of the at least two active lead wires are spaced from the second insulator surface.

19. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 18 wherein the at least two lead wires are further supported by the insulator body.

20. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 18 wherein the shielded three-terminal flat-through filter is mounted directly onto at least a portion of the insulator body.

21. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 18 wherein the surface area of the at least two active electrode plates is maximized to increase parasitic capacitance to a minimum of 20 pf and minimize resistance to current flow.

22. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 18 wherein an insulative washer is disposed between the shielded three-terminal flat-through filter and the hermetic terminal.

23. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 18 wherein a first conductive pad is conductively coupled to the at least one lead wire at the first dielectric surface, opposite the insulator body, and wherein a second conductive pad is conductively coupled to the second active end of the active electrode plate.

24. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 23 wherein the first and second conductive pads comprise wire bond pads.

25. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 18 wherein at least one inductor is coupled in series along a length of at least one of the two active electrode plates so that the circuit current must pass through the at least one inductor.

26. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 25 wherein the at least one inductor in series with the at least one active electrode plate, and at least one of the first and second shield plates are configured to form at least one passive electronic low-pass filter selected from the group consisting of an “

L”

filter, a “

n”

filter, a “

T”

filter, an “

LL”

filter, a “

5 element”

filter, and an “

n”

element filter.

27. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 25 wherein the at least one inductor in series with the at least one active electrode plate, and at least one of the first and second shield plates are configured to form part of a bandstop filter or an L-C trap filter and wherein the bandstop filter or an L-C trap filter is configured to be resonant at an MRI frequency.

28. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 18 wherein at least one monolithic chip capacitor (MLCC) is conductively coupled between the at least one active electrode plate and either the at least one first shield plate or the at least one second shield plate.

29. A shielded three-terminal flat-through filter hermetic terminal assembly for an active implantable medical device (AIMD), the shielded three-terminal flat-through filter hermetic terminal assembly comprising:

a) a shielded three-terminal flat-through filter feedthrough filter, comprising;

i) a dielectric body with at least one active dielectric via hole and at least one ground dielectric via hole;

ii) at least one active lead wire supported in the at least one active dielectric via hole;

iii) at least one ground wire supported in the at least one ground dielectric via hole;

iv) at least one active electrode plate configured for carrying an electrical current and supported by the dielectric body, wherein a first active end of the at least one active electrode plate is conductively coupled to the active lead wire and a second active end of the active electrode plate is electrically connectable to an electronic circuit of the AIMD;

v) at least one first shield plate supported by the dielectric body on a first side of and spaced from the at least one active electrode plate; and

vi) at least one second shield plate supported by the first dielectric body on a second side of and spaced from the at least one active electrode plate, wherein the first and second shield plates are conductively coupled to the ground wire and are in a non-conductive relationship with the at least one active lead wire; and

b) a hermetic terminal comprising;

i) an insulator body comprising at least one active insulator via hole and at least one ground insulator via hole;

ii) at least one ground electrode plate disposed within the insulator body, and

iii) wherein the at least one ground wire in the at least one ground dielectric via hole extends at least part-way into the at least one ground insulator via hole, and

iv) wherein the at least one ground electrode plate is conductively coupled to the ground wire and to the ferrule or the AIMD housing, and

c) wherein the shielded three-terminal flat-through filter is disposed adjacent to the hermetic terminal, and

d) wherein the at least one active lead wire supported in the at least one dielectric via hole extends through the at least one active insulator via hole so that an end of the active lead wire is spaced from the insulator body opposite the dielectric body.

30. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 29 wherein a first metallization contacts the outer dielectric sidewall.

31. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 29 wherein the shielded three-terminal flat-through filter is mounted directly onto at least a portion of the insulator body.

32. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 29 wherein the surface area of the at least one active electrode plate is maximized to increase parasitic capacitance to a minimum of 20 pf and minimize resistance to current flow.

33. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 29 wherein an insulative washer is disposed between the shielded three-terminal flat-through filter and the hermetic terminal.

34. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 29 wherein a first conductive pad is conductively coupled to the at least one lead wire at the first dielectric surface, opposite the insulator body, and wherein a second conductive pad is conductively coupled to the second active end of the active electrode plate.

35. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 34 wherein the first and second conductive pads comprise wire bond pads.

36. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 29 wherein at least one inductor is coupled in series along the length of the at least one active electrode plate so that the circuit current must pass through the at least one inductor.

37. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 36 wherein the at least one inductor in series with the at least one active electrode plate, and at least one of the first and second shield plates are configured to form at least one passive electronic low-pass filter selected from the group consisting of an “

L”

filter, a “

n”

filter, a “

T”

filter, an “

LL”

filter, a “

5 element”

filter, and an “

n”

element filter.

38. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 36 wherein the at least one inductor in series with the at least one active electrode plate, and at least one of the first and second shield plates are configured to form part of a bandstop filter or an L-C trap filter and wherein the bandstop filter or an L-C trap filter is configured to be resonant at an MRI frequency.

39. The shielded three-terminal flat-through filter hermetic terminal assembly of claim 29 wherein at least one monolithic chip capacitor (MLCC) is conductively coupled between the at least one active electrode plate and either the at least one first shield plate or the at least one second shield plate.