Ceramic-metal feedthrough lead assembly and method for making same
US4816621A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1987 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Nov 25, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49227
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A ceramic-metal lead assembly, of the type suitable for use in nerve or heart pacemakers, has a disk of high-purity ceramic with at least one lead extending therethrough, the disk being soldered vacuum-tight to a flange ring via a solder gap. The flange ring consists of a metal which is resistant to body electrolytes, and the coefficients of thermal expansion of the joined materials are matched to each other, but are not identical. For avoiding cracks in the ceramic disk in the region of the solder connection, the solder gap has a width such that the diffusion path of the metal of the flange ring into the solder connection cannot exceed a selected distance in the solder bridge which forms at the soldering temperature. A solder zone which is free of the metal of the flange ring, and thus has a dutility which is not degraded by the flange ring metal, is formed around the ceramic disk.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.