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AssigneePanasonic Corporation
InventorsAtsushi Utsubo, Makoto Horiuchi, Makoto Kai, Hiroshi Nohara
Estimating the term…
A metal halide lamp according to the present invention includes: a main tube (6) made of a light-transmitting ceramic and forming a part of an arc tube; a first thin tube (7a) coupled to a first end of the main tube (6); a second thin tube (7b) coupled to a second end of the main tube (6); a pair of electrodes (5a, 5b), which are inserted into the first and second thin tubes (7a, 7b), respectively, such that the far ends thereof face each other inside the main tube (1); and a first metal halide enclosed in the arc tube. A second metal halide, which has a lower vapor pressure than that of the first metal halide, is further enclosed in the arc tube. And the main tube (6) has portions, of which the inside diameter decreases monotonically toward the ends.
A metal halide lamp comprising an arc tube and a first metal halide that is enclosed in the arc tube,
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Selection of substances for gas fillings; Specified operating pressure or temperature: having an halogenide as principal component
Lamps with high-pressure unconstricted discharge having a cold pressure > 400 Torr: metal halide arc lamps
Electric discharge tubes or discharge lamps
Term ended 5 Dec 2024 (estimated)
This is a continuation of International Application PCT/JP2004/005652, with an international filing date of Apr. 20, 2004.
The present invention relates to a metal halide lamp with an arc tube made of a light-transmitting ceramic.
In the past, the arc tube of a metal halide lamp was made of quartz glass. Recently, however, an arc tube made of a light-transmitting ceramic, which has higher thermal resistance, higher shape stability and higher resistibility to halide than quartz, has been adopted extensively.
FIG. 1 is a cross-sectional view illustrating a configuration for a conventional arc tube for use in a metal halide lamp.
FIG. 2 is a cross-sectional view schematically illustrating the sealing structure of the arc tube shown in FIG. 1.
FIG. 3 is a front view illustrating a preferred embodiment of a metal halide lamp according to the present invention.
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
In a metal halide lamp according to the present invention, a metal halide, having a lower vapor pressure than a rare-earth halide, is enclosed in an arc tube to prevent the rare-earth halide from eroding the sealing material. In the following description, a metal halide with a relatively high vapor pressure (more specifically, a halide of at least one metal selected from the group consisting of dysprosium, holmium and thulium) will be referred to herein as a “first metal halide”, and another metal halide, having a lower vapor pressure than the first metal halide, will be referred to herein as a “second metal halide”. In a preferred embodiment, the second metal halide is a halide of at least one metal selected from the group consisting of calcium, strontium, barium, lanthanum, samarium and europium.
As used herein, the “vapor pressure” refers to a vapor pressure value to be measured at the temperature of the sealing portions while the lamp is ON.