| 摘要 |
PURPOSE:To accelerate start and the stability of optical output and maintain luminous efficiency with high efficiency by always locating a principal amalgam or a principal metal body at the uppermost section of a luminous tube and providing an auxiliary metal body for forming auxiliary amalgam or amalgam at the high temperature section in the vicinity of an electrode. CONSTITUTION:When optical output is transferred to the stable state, amalgamate mercury is all evaporated and the intra-tube mercury vapor pressure is controlled by the vapor pressure that is determined by the temperature of the principal amalgam formed by a principal metal body 21, that is, the principal metal body 21. In this case, since the metal body 21 for forming the principal amalgam is housed in a luminous tube 5 so as to freely move, the temperature difference between an auxiliary metal body 22 in the vicinity of an electrode 11 and the metal body 21 located in the coolest section can be increased even when the fluorescent lamp unit is lit making a metal cap 2 face either upward or downward. As a result, when the optical output is transferred to the stable state, the mercury vapor pressure of a luminous tube 5 at stability is controlled to the vapor pressure that is determined by the temperature of the principal metal body by setting the peak temperature so as to evaporate the auxiliary amalgam mercury. |
