Process for fabricating a hermetic coaxial feedthrough
AssigneeCoors Ceramics Company
InventorsRobert J. Marquit, Douglass R. Gooch, James E. Knight
Life of this patent
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Abstract
The present invention relates to a process for fabricating a hermetic coaxial feedthrough device wherein a pin is substantially centered within the device. The pin can be electrically connected to the outer portion of the device via a bridge wire to form a header that is particularly useful for igniting a gas-generating composition in an air bag device. The invention also provides an eyelet useful in the process and an improved header device having a substantially smooth surface.
Claims44
A process for the fabrication of a hermetic coaxial feedthrough device, comprising the steps of:
- a) providing an eyelet comprising a cavity, said cavity terminating at an upper surface, and further comprising notch means on said upper surface for engaging the end of a pin;
- b) placing a glass tube substantially within said cavity, said glass tube defining a bore therethrough;
- c) inserting a pin through said bore wherein an end of said pin engages said notch means;
- d) fusing said glass to create a substantially hermetic seal;
- and
- e) removing said upper surface of said eyelet to expose said fused glass.
A process for the fabrication of a header, comprising the steps of:
- a) providing an eyelet having an outer diameter and a cavity, said cavity terminating at an upper surface, said upper surface comprising vent means for venting gas and notch means for engaging the end of a pin;
- b) placing a glass tube into said cavity, said glass tube defining a bore therethrough and said glass tube having a thermal expansion coefficient that is lower than the thermal expansion coefficient of said eyelet;
- c) inserting a conductive pin through said bore wherein an end of said conductive pin engages said notch means;
- d) fusing said glass to create a substantially hermetic seal;
- e) removing the lower surface of said eyelet to expose said glass;
- and
- f) connecting said end of said pin with said eyelet by placing a bridge wire on said glass.
A process for the fabrication of a header, comprising the steps of:
- a) providing an eyelet comprising:
- i) an outer diameter;
- ii) a cavity terminating at an upper surface;
- iii) notch means substantially centered on said upper surface for engaging a pin;
- and
- iv) vent means on said upper surface for venting a gas;
- b) attaching a ground pin to said eyelet;
- c) placing a glass tube defining a bore therethrough substantially within said cavity, wherein said glass tube is substantially free from bubbles having a diameter of greater than about 0.015 inches and having a thermal expansion coefficient lower than the thermal expansion coefficient of said eyelet;
- d) inserting a conductive pin through said bore wherein and end of said conductive pin engages said notch means and substantially self-centers within said eyelet;
- e) placing said eyelet, said ground pin, said glass and said conductive pin into a fixture, said fixture comprising means for engaging said conductive pin;
- f) heating said fixture to fuse said glass in a substantially non-oxidizing atmosphere and form a fused blank;
- g) cooling said fixture and removing said blank from said fixture;
- and
- h) machining said blank to remove said upper surface therefrom and expose said fused glass.
An eyelet for fabricating into a hermetic coaxial feedthrough, comprising:
- a) an outer diameter;
- b) a bore substantially centered within said eyelet, said bore terminating at an upper surface of said eyelet;
- c) notch means on said upper surface of said eyelet for engaging the end of a pin to center said pin within said eyelet;
- and
- d) vent means for venting gas from a glass contained within said bore during a fusing operation.
Dependencies are inferred from the claim text.