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AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsMituhiko Kimoto, Taku Ikeda, Hiroshi Sugimoto, Takeshi Fujikawa
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The present invention provides a tungsten-halogen light bulb having an arc tube with a seal portion at one end. A filament is provided in the interior of the arc tube, and a basic gas mainly comprising at least either gaseous xenon or gaseous krypton is filled in the arc tube. When V (V) denotes a rated voltage of the tungsten-halogen light bulb, P(MPa) denotes a filling pressure of the basic gas at a room temperature, and Xe vol. % and Kr vol. % respectively denote composition ratios of the gaseous xenon and of the gaseous krypton, the following formulas (1) and (2) are satisfied simultaneously, in which ‘%’ means ‘volume %’. V≧100 (Volt) (1) P≧0.7+{0.1×(Kr%/(Kr%+Xe%))} (2) In these formulas, Kr %+Xe %=100(%), 0≦Kr %≦100, and 0≦Xe %≦100. Accordingly, a crack at the seal portion of the arc tube is prevented and the lifetime is improved.
A tungsten-halogen light bulb comprising an arc tube with a seal portion at an end, a filament is provided in an interior of the arc tube and a basic gas mainly comprising at least one gas selected from the group consisting of gaseous xenon and gaseous krypton is filled, wherein
A reflector lamp, comprising a tungsten-halogen light bulb in the lamp and a reflector provided with a front glass, and the tungsten-halogen light bulb comprises an arc tube with a seal portion at an end and a filament provided in an interior of the arc tube, and a basic gas mainly comprising at least one gas selected from the group consisting of gaseous xenon and gaseous krypton is filled, wherein both formulas (1) and (2) are satisfied when V (Volt) denotes a rated voltage of the tungsten-halogen light bulb, P (MPa) denotes a filling pressure of the basic gas at a room temperature, and Xe vol. % and Kr vol. % denote respectively composition ratios of the gaseous xenon and of the gaseous krypton;
Dependencies are inferred from the claim text.