Sealing structure for light-emitting bulb assembly and method of manufacturing same

Abstract

A sealing structure for a light-emitting bulb assembly includes a closure, having a core which serves as an electrode for sealing an open end of a bulb. The closure includes a bulb-side region disposed adjacent to the open end of the bulb and made of a compositional ingredient having a coefficient of thermal expansion which is substantially the same as that of the bulb, a core-side region disposed adjacent to the core and made of a compositional ingredient having a coefficient of thermal expansion which is substantially the same as that of the core, and an intermediate region disposed between the bulb-side region and the core-side region and made of a compositional ingredient having compositional proportions adjusted such that a coefficient of thermal expansion thereof varies gradually from the coefficient of thermal expansion of the bulb-side region toward the coefficient of thermal expansion of the core-side region. The bulb-side region and the core-side region are separated from each other by the intermediate region and comprise a bulb-side region layer and a core-side region layer, respectively, which are independent of each other. The intermediate region comprises at least one layer whose coefficient of thermal expansion varies gradually from the bulb-side region toward the core-side region. The layers of the closure are progressively thicker from the bulb-side region layer toward the core-side region layer.

Dependencies are inferred from the claim text.