Ground Connection Made By A Notch In The Outer Diameter Of A Ceramic Insulator For An Internally Grounded Filter Feedthrough

A feedthrough, comprising:

• a) a ferrule defining a ferrule opening extending to a ferrule device side opposite a ferrule body fluid side;
• b) an insulator hermetically sealed to the ferrule in the ferrule opening, the insulator having a thickness defined by an insulator sidewall extending to an insulator device side residing at or adjacent to the ferrule device side and an opposed insulator body fluid side residing at or adjacent to the ferrule body fluid side;
• c) at least one active conductive pathway extending through the insulator thickness to the device and body fluid sides;
• d) at least one ground conductive pathway extending part-way through the insulator thickness from the insulator device side;
• e) an undercut extending into the insulator sidewall so that the undercut is in communication with the at least one ground conductive pathway;
• and
• f) a braze hermetically sealing the insulator sidewall to the ferrule.

An internally grounded filter feedthrough, comprising:

• a) a feedthrough, comprising:
• i) a ferrule defining a ferrule opening extending to a ferrule device side opposite a ferrule body fluid side;
• ii) an insulator hermetically sealed to the ferrule in the ferrule opening, the insulator having a thickness defined by an insulator sidewall extending to an insulator device side residing at or adjacent to the ferrule device side and an opposed insulator body fluid side residing at or adjacent to the ferrule body fluid side;
• iii) at least one active conductive pathway extending through the insulator thickness to the insulator device and body fluid sides;
• iv) at least one ground conductive pathway extending part-way through the insulator thickness from the insulator device side;
• v) an undercut extending into the insulator sidewall so that the undercut is in communication with the ground conductive pathway;
• and
• vi) a braze hermetically sealing the insulator sidewall to the ferrule, wherein the braze extends into the undercut so that the braze is in contact with the ground conductive pathway;
• b) a filter capacitor, comprising:
• i) a dielectric substrate supporting at least one active electrode plate interleaved in a capacitive relationship with at least one ground electrode plate, wherein the dielectric substrate has a substate sidewall extending to a first end surface opposite a second end surface;
• ii) a capacitor active via extending through the dielectric substrate to the first and second end surfaces, wherein the active electrode plate is electrically connected to the capacitor active via;
• and
• iii) a capacitor ground via extending through the dielectric substrate to the first and second end surfaces, wherein the ground electrode plate is electrically connected to the capacitor ground via,
• c) wherein the dielectric substrate first end surface is positioned adjacent to the insulator device side with the capacitor active via connected to the active conductive pathway extending through the insulator so that an active electrical path extends from the capacitor active via at the second side of the dielectric substrate to the active conductive pathway at the body fluid side of the insulator, and
• d) wherein the braze hermetically sealing the insulator sidewall to the ferrule also extends into the insulator undercut to contact the ground conductive pathway so that a ground electrical path extends from the capacitor ground via at the second side of the dielectric substrate to the ground conductive pathway in the insulator connected to the braze sealed to the ferrule.