Metal halide lamp and lighting device using same

Abstract

Provided is a metal halide lamp capable of being dimmed, which is prevented from non-lighting due to leakage of an arc tube attributable to a crack occurring at thin tubes, as well as realizing a desired color characteristic. The metal halide lamp has an arc tube that includes an envelope made of translucent ceramic, a pair of electrodes, and metal halides, the metal halides including rare earth metal halide, sodium halide, and magnesium halide, the rare earth metal halide being at least one of dysprosium halide, thulium halide, holmium halide, cerium halide, and praseodymium halide, and the magnesium halide being at least one of magnesium iodide and magnesium bromide, where when a maximum lamp power P (W) is in a range of 70 W to 250 W, the following relations are satisfied: <?in-line-formulae description="In-line Formulae" end="lead"?>0.0345A+0.0028B<0.0015P+0.0475;<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>A>=0.021P+0.313; and<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>B>=10.0,<?in-line-formulae description="In-line Formulae" end="tail"?> where A (mg) represents a total content of the metal halides, and B (mol %) represents a content ratio of the magnesium halide to the metal halides.

Description

technical field [0001] The invention relates to a metal halide lamp and an illuminating device using the metal halide lamp. In particular, the present invention relates to techniques for obtaining desired color rendering and preventing cracking of narrow tubes in dimmable ceramic metal halide lamps. Background technique [0002] Recently, from the viewpoint of energy saving, metal halide lamps capable of being dimmed are required. Specifically, it is the kind of lamp that can normally illuminate under high lamp power (rated power), and has the function of illuminating under lower lamp power when so much light is not needed. [0003] In metal halide lamps whose envelopes are made of transparent ceramics (hereinafter referred to as "ceramic metal halide lamps"), various types of rare earth metal halides such as dysprosium halide, thulium halide, holmium halide, halide Cerium and Praseodymium Halides. The envelope is composed of a main pipe in which a pair of electrodes are ...

AI Technical Summary

Problems solved by technology

However, this is also not a practical approach as it reduces the vapor pressure of each luminescent material during lamp illumination, which would compromise the desired color rendering

Images