A hermetic implantable medical device (IMD) is provided with a single or multi-pin arrangement including selected glass to metal seals for a feedthrough including a ceramic disk member coupled to the sealing glass surface in potential contact with body fluids. By judicious selection of component materials (ferrule, seal insulator and pin) provides for either compression or match seals for electrical feedthroughs (having a single or multi-pin array) provide corrosion resistance and biocompatibility required in IMDs. The resultant feedthrough configuration accommodates one pin within a single ferrule or at least two pins in a single ferrule having a pin surrounded by insulator material (e.g., alumina ceramic, zirconia ceramic, zirconia silicate ceramic, mullite, each having higher melting points than the sealing glass distributed around the pin within the ferrule, or feldspar porcelain materials or alumino-silicate glasses having a lower melting point than the sealing glass) distributed around the pin within the ferrule.
This invention relates to electrical feedthrough devices and particularly to single and multiple pin electrical feedthrough assemblies for providing electrical communication between electrical components such as medical electrical leads and diverse sensors and operative circuitry housed within the interior of a hermetically sealed implantable medical device (IMD).
BACKGROUND OF THE INVENTION
There are numerous applications where it is necessary to penetrate a sealed container with a plurality of electrical leads so as to provide electrical access to and from electrical components enclosed within. One such application for which the present invention has particular but not limited utility is in body implantable pulse generators (e.g. for treatment of bradycardia, tachyarrhythmia or for muscle or nerve stimulation) which includes neurostimulation devices, deep brain stimulators, and the like, herein referred to as implantable pulse generators (IPG’s). The heart pacemaker is a well-known example of one type of IPG. Typical devices of this type are formed of a metal container housing the electrical and power source components of the IPG with a lid or the like welded to the container to close the device and provide it with a hermetic seal. An electrical lead is electrically connected to the IPG by means of attachment to one or more feedthroughs which penetrate the container but maintain the hermetically sealed environment thereof. A typical feedthrough consists of an external metal part (a frame or ferrule) into which preformed solid or sintered glass part is sealed. Within the glass part, one or more metal leads (pins) are sealed. Since the reliability of critical implantable medical devices depend on hermetic sealing of various components, the integrity of the glass to metal seals used between the internal electrical components and the human body is of paramount importance.
Read more: Glass-to-metal feedthrough seals having improved durability particularly under AC or DC bias