| 摘要 |
PURPOSE: A discharge lamp is provided to obtain a long-life discharge lamp by removing the causes of lowering the service life of the discharge lamp owing to quartz glass constituting the discharge lamp and a gas sealed therein. CONSTITUTION: A discharge lamp comprises a light-emitting portion(1) formed of quartz glass, a pair of electrodes(3) disposed in the light-emitting portion, sealing portions(2a,2b) formed of quartz glass to hermetically seal the electrodes, and a noble gas charged in the light-emitting portion, wherein the contents of hydrogen, oxygen and their compounds existing in the noble gas in the light-emitting portion is such that a maximums of the light-emitting spectral spectra intensities of hydrogen, oxygen and their compounds is 1/1000 or less of an intensity of the main light-emitting spectrum of the noble gas when the noble gas is discharged by supplying a current of 3 mA to the electrodes in the light-emitting portion, and the content of OH groups included in the quartz glass of the sealing portion is 5 ppm or less by weight.
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