High-pressure discharge lamp, high-pressure discharge lamp apparatus, and light source

摘要

A cathode-side first sealed portion (14) and an anode-side first sealed portion (15) are respectively provided at the two opposing ends of a discharge space (21) of a discharge casing (11). A middle chamber (16) filled with a rare gas is provided adjacent to the anode-side first sealed portion (15). A second sealed portion (18) is provided adjacent to the middle chamber (16). Each sealed portion (14),(15),(18) is airtightly sealed by the pinch sealing method. A cathode (22) is welded to a metal foil conductor (24) disposed in the cathode-side first sealed portion (14). An anode (23) is welded to a metal foil conductor (32) disposed in the anode-side first sealed portion (15). The metal foil conductor (32) in the anode-side first sealed portion (15) and a metal foil conductor (35) in the second sealed portion (18) are connected to each other by means of a lead wire (33) passing through the middle chamber (16). A lead wire (36) that is drawn out of the lamp is welded to the metal foil conductor (35) in the second sealed portion (18). A sufficient distance from the discharge space (21), from which the heat is conducted, to the second sealed portion (18) exposed to the outside air can easily be ensured. Therefore, the invention is capable of ensuring the functioning of the high pressure discharge lamp (1) to the end of its life by protecting the welded portions of the lead wire (36) from deterioration, which may otherwise occur due to the exposure to the outside air at high temperature.