US 2014/0175975 A1Published application

Ceramic metal halide lamps with controlled cold spot

AssigneeGeneral Electric Company

InventorZoltan TOTH

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Abstract

Apparatus and methods for controlling the cold spot in a high-intensity discharge lamp. In an embodiment, an elongated arc tube has an inner wall defining a discharge chamber that includes a metal halide dose. A first leg extends from the arc tube in a first direction and a second leg extends from the arc tube in a second direction that is opposite the first direction. The first electrode is disposed within the first leg such that no voids exist between the first electrode and an entire inner portion of the first leg. Likewise, a second electrode disposed within the second leg has no voids between it and an entire inner portion of the second leg. The arc tube also has a first annular bucket structure within the discharge chamber formed by a nub surrounding the first tip and an interior wall portion, and a second annular bucket structure within the discharge chamber formed by a nub surrounding the second tip and a second interior wall portion. As a result, when the high-intensity discharge lamp is in a vertical operating position a cold spot is formed in one of the first and second annular bucket structures.

Claims14

Dependent claims

A high-intensity discharge lamp comprising:

an elongated arc tube including an inner wall that defines a discharge chamber;
a first leg extending from the arc tube in a first direction and a second leg extending from the arc tube in a second direction that is opposite the first direction;
a first electrode disposed within the first leg and having a first tip extending into the discharge chamber, wherein no voids exist between the first electrode and an entire inner portion of the first leg;
a second electrode disposed within the second leg and having a second tip extending into the discharge chamber opposite the first tip, wherein the first tip and the second tip define an arc gap therebetween, and wherein no voids exist between the second electrode and an entire inner portion of the second leg;
a dose disposed in the discharge chamber, the dose comprising alkali metal halide and at least one rare earth halide;
and
wherein the arc tube includes a first annular bucket structure within the discharge chamber formed by a nub that surrounds the first tip and an interior wall portion, and a second annular bucket structure within the discharge chamber formed by a second nub that surrounds the second tip and a second interior wall portion, such that when the high-intensity discharge lamp is in a vertical position a cold spot is formed in one of the first and second annular bucket structures.

4 more elements

Dependencies are inferred from the claim text.