| 摘要 |
PURPOSE: To eliminate spreading of the fusion time of a fuse and enhance the reliability of a high pressure discharge lamp by furnishing a gas-tight glass capsule containing a fuse and arc ignition circuit in the exhaust space of the discharge lamp, and filling the capsule with an oxidative atmosphere. CONSTITUTION: A discharge lamp 2 is furnished with an arc ignition circuit 10 containing a fuse 7 and a discharge vessel 3 surrounded through an exhaust space 6 by an outer pipe 30 on which a lamp base 31 is mounted. The vessel 3 is equipped with electrodes 4 and 5 between which electric discharge is generated while the lamp 2 is in lighting condition, and they 4 and 5 are connected with current supply conductors 40 and 50. A gas-tight glass capsule 12 with ignition circuit 10 is installed between these conductors 40 and 50, and the capsule 12 is filled with an oxidative atmosphere consisting of a mixture gas of N2 and O2 having a certain pressure. According to this configuration in which fuse is arranged in an oxidative atmosphere, the fuse is fused at a relatively low current intensity and in a short time, which should eliminate spreading of the fusion time to enhance the reliability of the fuse. |
