PURPOSE: To improve luminous efficiency and improve intensity by setting the sealing pressure of rare gas to 80-130Torr, and forming an electrode with a sintered sleeve and a sintered body containing an emitter material, fitted at the tip of a connection wire, and arranged in the sleeve.
CONSTITUTION: A lead wire 2 and a connection wire 43 are fixed at the center 41a of the bottom face of the bottomed cylindrical sintered sleeve 41 of an electrode, a sintered body 42 is fitted at the tip section of the connection wire 43, and a mercury getter 44 is welded to the lead wire 2. When the sealing pressure of rare gas is set to 80-130Torr, the intensity required for the back light of a word processor can be satisfied. A large quantity of an emitter material can be contained in the sturdy sintered body 42 of the electrode 4, the lighting life is extended, the sintered body 42 is covered with the sleeve 41, thus the emitter material is stuck to the inner face of the sleeve 41, not to a bulb 1, and the bulb 1 is rarely blackened.
UENARI SEIICHI
IKEUCHI MITSURU
ONISHI YASUO
MORITA AKIRA
