MERCURY VAPOR DISCHARGE LAMP

摘要

PURPOSE: A mercury vapor discharge lamp is provided to achieve improve luminance efficiency and lengthening the lifespan of the lamp, without increasing the input power of the lamp. CONSTITUTION: A mercury vapor discharge lamp comprises a pair of electrodes opposed to each other; and a windshield plate(30) disposed at the rear power supply side of the electrode, and which protect the rear power supply side of the electrode from over-cooling caused due to the air conditioning cooling air. The windshield plate includes a windshield flange portion(27) and a mounting portion(28) to be mounted to a mercury lamp(20). The windshield flange portion has a minimum diameter(D) which satisfies the relation of D >d, wherein d is the maximum diameter of a non-radiation aperture(26) of a conical mirror(21), to thereby prevent over-cooling of a luminous tube cooling portion(24) regardless of the air flow amount of bases(10,11).