Fluorescent lamp and process for fabricating the same

Abstract

In a fluorescent lamp of the type in which a lamp envelope comprises an outer bulb having generally a spherical or a partially spherical or a cylindrical configuration and an inner bulb inserted into the outer bulb in predetermined nested relationship; either of the inner surface of the outer bulb or the outer surface of the inner bulb is formed with a groove which defines a zig-zag discharge path between the outer and inner bulbs; a phosphor is formed at least over the wall surfaces of the groove; electrodes are disposed at the ends, respectively, of the discharge path and a uv (ultraviolet) radiation-emitting discharge gas consisting of mercury vapor and a rare gas or a rare gas mixture is filled in the discharge path, both the open end portions of the outer and inner bulbs are flared radially outwardly and inwardly respectively, or either of the open end portion of the outer or inner bulb is flared radially outwardly or inwardly so that glass frit can be filled into the annular space defined between the open end portions of the outer and inner bulbs both or either of which is flared. When glass frit is heated and then solidified, not only the open ends of the outer and inner bulbs can be gas-tightly sealed together but also lead-wires which also support the electrodes at the ends of the discharge path are also gas-tightly sealed.