ELECTRIC LAMP WITH INNER ASSEMBLY AND OUTER BULB AND METHOD FOR MANUFACTURING

摘要

An electric lamp comprises an inner assembly including a light source and a control gear circuit. An outer envelope encloses the light source and at least a part of the control gear and has a predetermined wall thickness and an end portion. The outer envelope is comprised of two parts separated along a circumferential line. The two parts of the envelope are connectable and sealable to form a uniform outer envelope with a seal region. The seal region has a wall thickness and is merged in a surface portion of the two parts of the envelope so that the surface unevenness of the seal region is not greater than 0.5 millimeters, and the maximum difference of the wall thickness of the seal region with respect to the wall thickness of the outer envelope is not greater than 0.3 millimeters. A method for manufacturing an electric lamp as described above is also disclosed. During connecting and sealing the two parts of the envelope by a welding process, the two parts are brought into a contacting position and compressed further by a first axial distance; and then the two parts are pulled apart from each other by a second axial distance in order to merge the seal region in a surface portion of the two parts, wherein the second axial distance is larger than the first axial distance.