Patent Application
20110015694
This application relates generally to hermetically sealed devices and, more specifically, but not exclusively to a prefabricated header for a hermetically sealed device.
Conventional implantable devices are sealed to prevent fluid and tissue from entering the devices. For example, in an implantable device constructed of a multi-section metal housing, the sections of the housing may be hermetically welded to hold the sections together and seal the device.
Some types of implantable devices connect to other implantable circuits. For example, an implantable cardiac device provides stimulation signals to and/or receives cardiac signals from one or more implantable cardiac leads. Accordingly, an implantable device may include a mechanism such as a header that provides connectivity to an external circuit. The housing of such an implantable device may include a hermetically sealed feedthrough for one or more electrical conductors. One side of this feedthrough is connected to a circuit located within the housing. After this connection is made, the housing is sealed.
The other side of the feedthrough is connected to a circuit (e.g., a connector) of the header. In some cases such a header may be constructed using a cast-in-place process. For example, a mold may be placed around the header circuit and an epoxy injected into the mold. Once cured, the epoxy forms a header body which is affixed to the housing.
In practice, a cast-in-place process may not be a particularly efficient manufacturing process. For example, a cast-in-place process is relatively complicated and generally involves the use of skilled labor. In particular, the epoxy should be properly mixed, the surfaces of the housing should be properly prepared, and strict preparation and curing times should be observed to facilitate adequate epoxy adhesion to the housing and provide a housing with sufficient structural integrity. Such labor dependent processes may, however, negatively affect the manufacturing yield. For example, when a header is not properly formed on the housing, the entire implantable device may need to be put through an extensive rework process. Also, a cast-in-place process typically has a relatively long cycle time and the equipment used in such a process may consume a relatively large amount of a manufacturing room floor. In view of the above, a need exists for more effective techniques for manufacturing implantable devices and associated components.
A summary of several sample aspects of the disclosure and embodiments of an apparatus constructed or a method practiced according to the teaching herein follows. For convenience, one or more aspects or embodiments of the disclosure may be referred to herein simply as “some aspects” or “some embodiments.”
The disclosure relates in some aspects to a header assembly that is hermetically welded to a housing of a device such as an implantable device. For example, a header assembly may include a metal base and a circuit embedded in an encapsulating material that is attached (e.g., adhered) to the metal base. The metal base is placed over an aperture defined in a housing of the device such that the metal base may be welded to the housing to complete the hermetic sealing of the device.
The metal base includes at least one hermetically sealed feedthrough for providing an electrical connection between one or more components located in the housing and the circuit of the header assembly. Once the metal base is welded to the housing, the feedthrough thereby provides connectivity between the internal and external circuits of the device, while maintaining a hermetical seal.
The header assembly may be prefabricated in some aspects to simply the manufacturing process for the device. For example, prior to assembly of the device, the connections between the header circuit and one side of the feedthrough may be made. In addition, the encapsulating material may be formed over the header circuit and the base. Consequently, assembly of the device may simply involve connecting the other side of the feedthrough to the internal component(s) of the device and welding the base to the housing of the device.
In some implementations the header assembly includes a battery assembly. For example, a battery assembly that is to be installed within the housing may be mechanically coupled to the header assembly via a coupling member that passes through the aperture of the housing. In some implementations this mechanical coupling may be accomplished by a bracket or other suitable mechanism attached to the base of the header assembly.
In some aspects, through the use of these and other techniques as taught herein, a device such as an implantable device may be manufactured in a more efficient manner. For example, the use of a welding (e.g., laser welding) process to attach a header assembly to a device may result in higher yields (e.g., less scrap or rework) than conventional techniques. Such a process may be automated (e.g., using a robotic welder). In addition, it may be easier to verify and inspect the quality of such an attachment (e.g., the quality of a weld may be easily inspected). Also, the manufacturing time of such an operation may be shorter than the manufacturing times associated with conventional techniques (e.g., which may involve relatively long cure times for the header material).
These and other features, aspects, and advantages will be more fully understood when considered with respect to the following detailed description, the appended claims, and the accompanying drawings, wherein:
In accordance with common practice the various features illustrated in the drawings may not be drawn to scale. Accordingly, the dimensions of the various features may be arbitrarily expanded or reduced for clarity. In addition, some of the drawings may be simplified for clarity. Thus, the drawings may not depict all of the components of a given apparatus (e.g., device) or method. Finally, like reference numerals may be used to denote like features throughout the specification and figures.
The description that follows sets forth one or more illustrative embodiments. It will be apparent that the teachings herein may be embodied in a wide variety of forms, some of which may appear to be quite different from those of the disclosed embodiments. Consequently, the specific structural and functional details disclosed herein are merely representative and do not limit the scope of the disclosure. For example, based on the teachings herein one skilled in the art should appreciate that the various structural and functional details disclosed herein may be incorporated in an embodiment independently of any other structural or functional details. Thus, an apparatus may be implemented or a method practiced using any number of the structural or functional details set forth in any disclosed embodiment(s). Also, an apparatus may be implemented or a method practiced using other structural or functional details in addition to or other than the structural or functional details set forth in any disclosed embodiment(s).
The disclosure relates in some aspects to a header assembly that may be hermetically welded to a housing of a device, where the header assembly includes a hermetically sealed feedthrough for connecting circuitry in the header assembly to circuitry located within the housing. For illustrations purposes, these and other aspects of the disclosure will be described in the context of a header assembly for an implantable medical device (e.g., a pacemaker, an implantable cardioverter defibrillator, an implantable stimulation device, an implantable monitoring device, and so on). It should be appreciated, however, that the teachings herein may be applicable to other types of devices (e.g., devices that are not implanted).
The header assembly 106 includes at least one circuit (e.g., connectors 114 and 116 in
The base 108 includes a hermetically sealed feedthrough 124 for one or more conductors. As shown in
As will be described in more detail below, the housing 104 may be constructed of subcomponents (bottom portion 152 and top portion 154 in the example of
The components of a device as taught herein may be constructed of various materials. For example, for implantable devices, the housing 104 and the base 108 may be made of a biocompatible metal such as titanium, MP35N, or some other suitable material. In applications where the device is not implantable but is to be hermetically sealed, the housing and the base may be made of a material (e.g., a metal) that may be hermetically sealed (e.g., laser welded). Other materials may be used in other applications.
Various materials also may be used for the encapsulant. For example, the encapsulant may be a plastic, a thermoplastic, a two-part resin, an epoxy, a rigid silicone-based plastic (or thermoplastic), urethanes such as Elast-Eon™ by AorTech International PLC, or some other material that is suitable for a designated application. Also, the encapsulant may be formed over the header components in various ways. For example, epoxy casting, overmolding, injection molding, reaction injection molding, or some other suitable process may be employed.
In addition, various techniques may be employed to hermetically weld the metal components together. For example, techniques such as laser welding, ultrasonic welding, resistance welding, or some other type of welding may be employed in different embodiments.
A header assembly may include different types of circuits in different embodiments.
In some embodiments a header assembly may be fabricated with other components of an implantable device. For example, a header assembly may be prefabricated with a component that is to be placed within a housing of the implantable device.
Here, a coupling member 610 mechanically couples the battery assembly 606 to a base 612 of the header assembly 604. For example, one portion of the coupling member 610 may be mechanically coupled (e.g., by an attachment mechanism, spring contacts, a solder joint, a weld, a connector, an adhesive, and so on) to the battery assembly 606 and another portion of the coupling member 610 may be mechanically coupled (e.g., as just described) to the base 612 (e.g., to a feedthrough 614 as shown). Alternatively, the coupling member 610 may comprise part of the structure of the battery assembly 606 or the base 612, and is configured to extend to and be coupled with the other component. The coupling member 610 may be constructed of a various materials such as, for example, plastic or metal. In some embodiments the coupling member 610 comprises a flex cable.
The coupling member 610 may include one or more conductors that are coupled to conductors of the feedthrough 614 and/or the battery assembly 606. For example, in the example of
In some embodiments one or more connectors may be used to couple one or more of the contacts 618-626 to conductors of the battery assembly 606 and/or the feedthrough 612. For example, the coupling member 610 may include several plugs that plug into receptacles (not shown) of the battery assembly 606.
Once the header assembly 604 is in place, appropriate connections are made between the contacts 618, 620, 622, 624, and 626 and electrical conductors (e.g., contacts 628, 630, 632, 634, and 636) of the circuit 614. These connections may be implemented in various ways. For example, in some embodiments wires are connected (e.g., using wire bonds, solder, or a weld) to corresponding pairs of contacts as shown in
After the appropriate electrical connections are made between the feedthrough 614, the battery assembly 606, and the circuit 616, a top portion of the housing (e.g., similar to top portion 154 shown in
An implantable device as taught herein may take various forms. For example,
With the above in mind, an embodiment of a process for constructing an implantable device will be described with reference to
As represented by block 802 of
This subassembly may then be placed into a mold whereupon an encapsulant is injected into the mold. As the encapsulant cures, it becomes attached to the metal base (e.g., attached via a chemical bond and/or mechanically fastened). In addition, in embodiments where the header assembly includes a battery assembly, the metal base (e.g., the feedthrough) may be attached to the battery assembly through the use of a suitable coupling mechanism.
As represented by block 804, one or more circuits are installed in the housing of the implantable device. For example, as shown in
As represented by block 806, appropriate connections are made between the conductors (e.g., contacts) of the header assembly and corresponding conductors of the circuit that was placed in the housing. For example, as described above in conjunction with
As represented by block 808, the header assembly and the housing are assembled. Here, the header assembly is positioned over an aperture in the housing (e.g., the edges of the metal base may extend over the edges of the aperture so that the aperture is completely covered). In addition, in a case where the housing consists of multiple subcomponents, these subcomponents are assembled as well. As described above, when the header assembly is placed in the appropriate position relative to the housing, a portion of the feedthrough and/or conductors coupled to the feedthrough may extend through the aperture.
As represented by block 810, the assembled device is hermetically sealed. For example, all of the seams between housing subcomponents and between the header assembly and the housing may be hermetically welded as discussed above.
Various modifications may be incorporated into the disclosed embodiments based on the teachings herein. For example, the structure and functionality taught herein may be incorporated into devices other than the specific types of devices described above. In addition, a housing, a base, and an encapsulant may be made from materials that are different than the materials specifically mentioned above. Also different techniques may be employed to hermetically seal the components of a device together.
The various structures and functions described herein may be incorporated into a variety of apparatuses (e.g., a stimulation device, a monitoring device, etc.) and implemented in a variety of ways. Different embodiments of such an apparatus may include a variety of hardware and software processing components. In some embodiments, hardware components such as processors, controllers, state machines, logic, or some combination of these components, may be used to implement the described components or circuits.
Also, the recited order of the blocks in the processes disclosed herein is simply an example of a suitable approach. Thus, operations associated with such blocks may be rearranged while remaining within the scope of the present disclosure. Similarly, any accompanying method claims present operations in a sample order, and are not necessarily limited to the specific order presented.
In addition, it should be understood that any reference to elements herein using a designation such as “first,” “second,” and so forth does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more different elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be employed there or that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may comprise one or more elements.
While certain embodiments have been described above in detail and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive of the teachings herein. In particular, it should be recognized that the teachings herein apply to a wide variety of apparatuses and methods. It will thus be recognized that various modifications may be made to the illustrated embodiments or other embodiments, without departing from the broad scope thereof. In view of the above it will be understood that the teachings herein are intended to cover any changes, adaptations or modifications which are within the scope of the disclosure.
