CRYSTALLIZATION PREVENTING METHOD OF ELECTRIC DISCHARGE LAMP, AND ELECTRIC DISCHARGE LAMP

PROBLEM TO BE SOLVED: To obtain a long-life electric discharge lamp, which is prevented from becoming clouded by crystallization of its electric discharge container. SOLUTION: If the lamp is turned on, oxygen dissociates from powdered SiO2 , which has been filled up in a crevice between an internal electrode 3 and an electrode wearing hole 7, to become SiO gas, and as a result the partial pressure of SiO gas in a light emitting space 5 increases. Consequently, generating of the SiO gas from the silica glass which constitutes the electric discharge container 1 is suppressed, and it can be prevented that the electric discharge container 1 itself becomes lean (it becomes thin). Furthermore, the partial pressure of O2 gas in the light emitting space 5 has been become also high because oxygen has dissociated from SiO2 , consequently the reaction of the SiO →metallic Si is also suppressed, and generating of the metal Si leading to crystallization can also be suppressed.