| 摘要 |
In order to obtain light of a high luminance in a gas discharge tube of the present invention, a discharge path is narrowed by a first opening 18 and a second opening 13 in collaboration. Further, in order to provide favorable startability in a lamp even when the discharge path is narrowed, a predetermined voltage is applied from the outside to first and second discharge path limiting portions 16, 12. As a result, an active starting discharge which is capable of passing through the first and second openings is produced between a cathode portion 20 and the first and second discharge path limiting portions 16, 12, and thus discharge between the cathode portion 20 and an anode portion 8 is started speedily. Further, the anode portion, cathode portion, first discharge path limiting portion, and second discharge path limiting portion are housed within a light-emitting portion assembly 6 and electrically connected by first through fourth stem pins 9A to 9D, and the stem pins are utilized effectively to support the light-emitting portion assembly. <IMAGE> |
