Patent ID: 7791259
Filing Date: 2010-09-07
Classification: H01J,H01K

Abstract:
1. An electric lamp comprising a base at one end and having an axis (A) and an inner vessel, the inner vessel sealed in a vacuum-tight manner, said inner vessel being surrounded by an enveloping part, and wherein the base comprises electrical terminals and bears the inner vessel and the enveloping part and wherein: a) the base includes a base insulator comprising an insulating material, which base insulator has a central opening with a surrounding collar in which the inner vessel is accommodated by means of a cementless fastening means; b) the base insulator has a first fastening means for the enveloping part; c) the enveloping part has an opening at the base end and a second fastening means, located in the vicinity of the opening, for fastening it to the base insulator; and further wherein the cementless fastening means is an adapter part comprising a ceramic material and further wherein the adapter part and the base insulator respectively have indexing means and mating indexing means for holding the base insulator and the adapter part in relative position, and wherein the indexing means has a radially protruding projection in the vicinity of the adapter's end remote from the inner vessel, wherein the projection interacts in a holding fashion with at least one mating indexing means, the mating indexing means being a cutout of the collar in the interior of the central opening of the base insulator, and wherein a plurality of identical mating indexing means are arranged in the central opening along the axis (A), such that the adapter is capable of being inserted into the collar of the base insulator with differing physical depth.