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US 6,724,145 B1Granted
Discharge lamp
AssigneeStanley Electric Co., Ltd.
InventorsMasaaki Muto, Shigeru Shibayama, Hiroharu Shimada, Isamu Sato, Shinya Omori, Yasuhisa Yaguchi, Naoyuki Matsubara, Yoshifumi Takao, Toshiyuki Nagahara
Life of this patent
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Abstract
The invention provides an arc tube with improved chromaticity and start-up characteristics that does not contain mercury, and provides a vehicle headlamp equipped with a metal halide lamp that contains no mercury in the arc tube. Among other improvements, the evaporation of low melting point metal halides is promoted and the start-up characteristics of the arc tube are improved.
Claims21
A discharge lamp, comprising:
- an arc tube having a discharge space including substantially no mercury;
- a pair of electrodes facing each other in the discharge space;
- and
- a low melting point metal halide with a melting point less than or equal to approximately 400° C. and a rare gas enclosed at high pressure in a range of approximately 7-20 atms in the discharge space in such a manner as to create a hot plasma at a high temperature and pressure, promote an increase in tube wall temperature, and vaporize the metal halide to emit light.
1 more element
A metal halide lamp, comprising:
- an arc tube having a discharge space including substantially no mercury;
- a pair of electrodes projecting in such a manner as to face each other in the discharge space within the arc tube, a substantially cylindrical arc capable of being generated between ends of the pair of electrodes;
- a buffer gas serving as a starter gas and including xenon at a pressure of between approximately 7 to 20 atms at room temperature located in the discharge space;
- one of sodium halide, scandium halide, and a compound of sodium halide and scandium halide located in the discharge space;
- and
- a low melting point metal halide with a melting point less than or equal to approximately 400° C. located in the discharge space.
3 more elements
A metal halide lamp, comprising:
- an arc tube having a discharge chamber including substantially no mercury;
- a pair of electrodes projecting in such a manner as to face each other in the discharge space within the arc tube, with a substantially cylindrical arc capable of being generated between ends of the pair of electrodes;
- a buffer gas serving as a starter gas located in the discharge space and including xenon at a pressure of approximately 7 to 20 atms at room temperature;
- one of sodium halide, scandium halide and a compound of sodium halide and scandium halide located in the discharge space;
- and
- a low melting point metal halide with a melting point less than or equal to approximately 400° C. located in the discharge space, wherein
- an internal diameter of the arc tube is within a range of approximately 0.6 mm to 1.7 mm larger than a diameter of the arc between the ends of the electrodes, and the electrodes protrude into the discharge space a length of approximately 1.0 mm to 1.7 mm, a mole content ratio of sodium halide to scandium halide is approximately 1.0 to 15, and a mole content ratio of the low melting point metal halide to the scandium halide is in a range of approximately 0.5 to 3.0.
4 more elements
A metal halide lamp, comprising:
- an arc tube having a discharge chamber including substantially no mercury;
- a pair of electrodes projecting in such a manner as to face each other in the discharge space within the arc tube, with a substantially cylindrical arc capable of being generated between ends of the pair of electrodes;
- a buffer gas serving as a starter gas located in the discharge space and including xenon at a pressure of approximately 7 to 20 atms at room temperature;
- one of sodium halide, scandium halide and a compound of sodium halide and scandium halide located in the discharge space;
- and
- a low melting point metal halide with a melting point less than or equal to approximately 400° C. located in the discharge space, wherein
- an internal diameter of the arc tube is within a range of approximately 0.6 mm to 1.7 mm larger than a diameter of the arc between the ends of the electrodes, and the electrodes protrude into the discharge space a length of approximately 1.0 mm to 1.7 mm, and a mole content ratio of sodium halide to scandium halide is approximately 1.0 to 15.
4 more elements
Dependencies are inferred from the claim text.