Short-arc discharge lamp
AssigneeORC Manufacturing Co., Ltd.
InventorsIzumi Serizawa, Masaaki Miyazawa, Akiyoshi Fujimori
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Abstract
To realize high irradiation efficiency and intensity stability for extending lifetime of the short-arc discharge lamp to be used for IC exposure apparatus or the like. For this end, mercury and rare gases are sealed in the inner space 21 of the discharge tube 1. The rare gases are a mixture of a relatively high molecular weight rare gas such as xenon, krypton, argon, etc. and 5%-40% by volume of a relatively low molecular weight rare gas such as helium, neon, etc. And pressure of the mixed rare gases is set to 2 atmospheric pressure or higher. The anode 3 comprises the columnar body portion 14, the tapered portion 13 and the flat portion 12.
Claims7
A short-arc discharge lamp including a cathode and an anode in an opposed relationship within a discharge tube and also having mercury and rare gases sealed in the space of the discharge tube, characterized in that the rare gases are a mixture of a high molecular weight rare gas and a low molecular weight rare gas of approximately 5%˜ approximately 40% by volume with respect to the high molecular weight rare gas, and that the pressure of the mixed gases is set to 2 atmospheric pressure or higher at normal temperature.
A short-arc discharge lamp of claim, wherein the distance L (mm) of the point having the current density of 0.3A per square mm from the end of the anode is set to 0.05I<L<0.08I, where I represents the discharge current.
Dependencies are inferred from the claim text.