The present invention relates to an ultraviolet lamp comprising a glass
shell and an electrode fixed on one or more ends of the lamp, where each
electrode is a coiled wire with a hollow conical shape. The hollowed
conical structure of the electrode reduces the thermal capacity of the
electrode as compared with other types of electrodes of the same mass,
makes the lamp start quicker, and decreases the emission loss of the
electrode when the glow discharge is transformed to an arc discharge. The
lamp of the present invention has a wide electrode surface area, such
that the loads on each point of the emissive surface are equally
distributed, thus decreasing the electron scattering and dispersion, and
allowing the lamp to resist the impact from positive ions. Due to the
shape and structure of the electrode, the lamp of the present invention
has increased efficiency and emitting ability, and allows for a longer
lasting lamp.