| 摘要 |
Provided are a light-emitting tube and lamp that can maintain a high lamp efficiency even if the lamp power fluctuates. The light-emitting tube (3) comprises a hermetically sealed glass tube (19), and electrodes (17, 18) are disposed at both ends (13, 15) of said glass tube. The glass tube (19) has a bulging part (37) in a center area that roughly corresponds to the center of the interelectrode region between filament coils (25, 26) at the electrodes (17, 18). When the light-emitting tube is lit at a rated lamp power, the lowest-temperature point is in an end region outside of the interelectrode region, and when lit at a prescribed lamp power below the rated lamp power, said lowest-temperature point is in the bulging part (37). The lamp comprises the abovementioned light-emitting tube (3) and a socket that electrically connects to the electrodes (17, 18) inside the light-emitting tube (3). |
