DISCHARGE LAMP DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding part which shields electromagnetic wave leakage and can increase light flux of a discharge lamp since shielding of radiation light is less and a ceiling part is not required.SOLUTION: An electromagnetic wave shielding part is formed in a cylindrical shape by a plurality of conductive members extending in the axial direction of a coaxial waveguide. The length of a circular waveguide structure of the electromagnetic wave shielding part is set to 1/4 of wavelength of the electromagnetic wave, the diameter of the electromagnetic wave shielding part is set to the diameter which achieves an evanescent mode in relation with the electromagnetic wave, and the opening ratio in the circumferential direction is made to be 91% or less.