| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal-halide lamp in which starting voltage is reduced, a milky portion is hardly produced at a part enclosing an electrode of an airtight container and mercury is not enclosed in it, and a lighting device with the metal-halide lamp. SOLUTION: A metal-halide lamp comprises an airtight container 1 having an inner capacity of 0.1 cc or less; a pair of electrodes 1b spaced from each other by a distance L mm of 3.8-4.6 mm and enclosed in the airtight container so that a projecting length l (mm) of at least one of the electrodes meets formula, 0.8≤l≤1.3; and an electric discharge medium including a metal halide containing a first halide of Sc and Na and at least one sort of a second halide selected from In and Zn and rare gas, sealed in the airtight container and not substantially including mercury, wherein the minimum distance d mm between the tip of at least one of a pair of the electrodes 1b and the inner face of the enclosing portion meets a formula 2, 0.11≤d/L≤0.24. COPYRIGHT: (C)2005,JPO&NCIPI
|
