An electrolytic capacitor is provided having a metal-to-glass hermetic seal assembly wherein a glass body containing an effective amount of chromic oxide is directly bonded outwardly and inwardly to a film-forming metal such as tantalum. The glass has a mean thermal coefficient of expansion which is not greater than that of the metal of the seal and does not differ therefrom substantially over a wide temperature range, thus resulting in a substantially matched or slight compression type of seal. All components of the seal exposed to contact with the electrolyte are resistant to sulfuric acid. In one embodiment, utilizing an all-welded tantalum case, a substantial reverse voltage capability is made possible. A fluorocarbon spacer ring separating the porous anode from the casing wall and a thin ceramic heat shield for protection of the anode during welding assembly of the case also provide a cushioning effect for vibration and shock resistance.
A hermetic metal-to-glass-to-metal seal for a sealed casing is disclosed comprising an outer metal member and an inner metal member, one of which is a film-forming metal. The inner member extends through an acid-resistant glass member which is sealed to both metal members.
Tantalum or niobium feedthrough conductor pins are provided with a thin, vacuum deposited metal coating to control oxidation growth during feedthrough fabrication. The coated feedthrough pins are incorporated into a feedthrough which includes a capacitive structure in electrical contact with the coated pin.
A hermetically sealed, electrolytic capacitor is provided having a lid incorporating a liquid seal on the wet side of the lid and a hermetic seal on the dry side of the lid. The lid includes a plate, with a hole through its thickness, and a flange creating an orifice in the hole, adjacent the underside of the lid. A liquid seal is positioned in the orifice and has a terminal insulated from the plate by an elastomeric ring. The terminal is electrically connected to the capacitor element on its wet side, and the terminal is electrically connected to the hermetic seal on its dry side.
An electrolytic capacitor is provided having a metal-glass-metal hermetic seal and a liquid seal, which protects the hermetic seal from the electrolyte solution in the capacitor. The liquid seal is formed by compressing an elastomeric ring between the underside of the lid of the capacitor and a terminal plate, connected to the capacitor element, whereby compression of the elastomeric seal is maintained by the lead, which connects the terminal plate and a metal post in the hermetic seal.
A capacitive filter feedthrough assembly and method of making same are disclosed for shielding an implantable medical device such as pacemaker or defibrillator from electromagnetic interference or noise. A ferrule is adapted for mounting onto a conductive device housing by welding, soldering, brazing or gluing, and supports a terminal pin for feedthrough passage to a housing interior. A capacitive filter is mounted at the inboard side of a device housing, with capacitive filter electrode plate sets coupled respectively to the housing and the terminal pin by an electrically conductive combination of adhesive, brazing and soldering. In one embodiment of the invention, multiple capacitive filters are provided in an array within a common base structure, where each capacitive filter is associated with a respective terminal pin.
