Capacitor with dual element electrode plates

• US 5,978,204 A
• Filed: 11/18/1996
• Issued: 11/02/1999
• Est. Priority Date: 11/27/1995
• Status: Expired due to Term

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Maxwell Energy Products Incorporated
• Inventors: Stevenson, Robert A.
• Primary Examiner(s): Reichard, Dean A.
• Assistant Examiner(s): Dinkins, Anthony
• Application Number:
  US08/751,903
• Time in Patent Office: 1,079 Days
• Field of Search: 361/311-313, 361/303, 361/308.1, 361/320-321.5, 361/304
• US Class Current: 361/303
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 4/005 Electrodes
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors

Abstract

An improved capacitor is provided particularly for use in electromagnetic interference (EMI) filter applications, for example, in an implantable medical device such as a heart pacemaker or defibrillator, to accommodate relatively high pulse currents. The capacitor comprises a plurality of active and ground electrode plates interleaved and embedded within a dielectric casing of ceramic or the like with each active and ground plate being defined by a closely spaced pair of conductive plate elements which significantly increase the total area of each electrode plate, and thereby correspondingly increase the current handling capacity of the capacitor.

Claims

1. A capacitor assembly, comprising:

a substantially monolithic casing of dielectric material having a plurality of conductive active and ground electrode plates encased therein in an alternating stack and in predetermined spaced relation;

each of said active and ground electrode plates comprising a pair of closely spaced conductive plate elements of the same length and separated by a thin layer of dielectric material to preserve the capability of the capacitor assembly to reliably withstand inrush currents from voltage pulses and surges.

2. The capacitor assembly of claim 1 wherein said casing is formed from a ceramic material.

3. The capacitor assembly of claim 1 wherein said casing has a rectangular shape.

4. The capacitor assembly of claim 1 wherein said casing has a discoidal shape.

5. The capacitor assembly of claim 1 further including a first conductive termination surface on said casing and electrically connected to said active electrode plates, and a second conductive termination surface on said casing and electrically connected to said ground electrode plates.

6. The capacitor assembly of claim 1 wherein said active and ground electrode plates are encased within said casing in generally parallel relation with a spacing therebetween of about 5 to 10 mils, and further wherein said pair of conductive plate elements for each of said active and ground electrode plates are encased within said casing in generally parallel relation with a spacing therebetween at about 0.5 to 1.0 mil.

7. A capacitor assembly, comprising:

a substantially monolithic casing of dielectric material having a plurality of conductive active and ground electrode plates encased therein in an alternating stack and in predetermined spaced relation;

a first conductive termination surface on said casing and electrically connected to said active electrode plates; and

a second conductive termination surface on said casing and electrically connected to said ground electrode plates;

wherein each of said active and ground electrode plates comprising a pair of closely spaced conductive plate elements of the same length and separated by a thin layer of dielectric material to preserve the capability of the capacitor assembly to reliably withstand inrush currents from voltage pulses and surges.

8. The capacitor assembly of claim 7 wherein said active and ground electrode plates are encased within said casing in generally parallel relation with a spacing therebetween of about 5 to 10 mils, and further wherein said pair of conductive plate elements for each of said active and ground electrode plates are encased within said casing in generally parallel relation with a spacing therebetween at about 0.5 to 1.0 mil.

9. The capacitor assembly of claim 8 wherein said casing is formed from a ceramic material.

10. The capacitor assembly of claim 8 wherein said casing has a rectangular shape.

11. The capacitor assembly of claim 8 wherein said casing has a discoidal shape.