Production manner of the cold cathode of the cold cathode discharge lamp where it forms the film of BaCO 3 in the cold cathode discharge lamp null substrate which possesses

摘要

PROBLEM TO BE SOLVED: To improve the mass productivity by the expansion of a heating condition and to reduce the dispersion of characteristics by manufacturing a BaCO3 film formed on a board, by successively executing a vacuum heating process, a heating process in a wet gas of a water-contained carrier gas, and a vacuum heating process. ;SOLUTION: A lead-in wire 2 connected with a pair of electrodes 10 uniformly coated with BaCO3 slurry is welded in a glass tube 6 having a phosphor coating film on its inner surface, and BaCO3 is changed to BaCO1.3 by the heating in a first process after evacuation. A transparent uniform continuous film of Ba(OH)2 is formed by the heating in a second process preferably in a rare gas of at least 1 Torr including the moisture of not less than the saturated vapor of a water temperature, or the like, and further it is changed to BaO by the vacuum heating in a third process. The heating is preferably executed at least 800°C in the first and third processes, and at least 408°C in the second process. The electrodes 10 of the uniform continuous film free from unevennss, hardly depend on an electric current of lamp voltage. Further BaO is produced from Ba(OH)2 of a decomposition temperature lower than that of BaCO3, which dispenses with the high temperature and quick heating.;COPYRIGHT: (C)2001,JPO