Abstract:
A metal member is hermetically sealed to the surface of a wall of a glass member or article such as a reflector portion for a sealed beam automobile headlight lamp. The metal member preferably supports an electrical lead-in conductor which is inserted through a passage embodied in a wall of the glass article for the purpose, for example, of making an electrical connection to an electrical component such as a filament used in a completed headlight lamp using the glass article. The hermetic seal is made between the surface of the glass member which surrounds the passage and a surface of the metal member which is positioned adjacent the glass surface surrounding the passage. In making the hermetic seal, the surface of the glass surrounding the passage is metallized by providing it with an annulus or band of silver paint or other solderable, hermetic and adherent material having a precious metal content and, therefore, having a relatively high temperature coefficient of thermal expansion. The band or annulus and the surface of the metal member facing the annulus are tinned with solder and are then soldered to each other. By using, for the metal member, a material having a relatively low coefficient of thermal expansion, the relatively high expansion silver paint-solder combination is compensated for and a thermal shock resistant glass-to-metal seal results. In a modified form of the invention, the metal member is provided with an orifice or passage for purpose of exhausting a complete lamp.