Mercury-free metal halide lamp for vehicle and metal halide lamp device

Abstract

A mercury-free metal halide lamp for a vehicle according to an embodiment includes an airtight vessel 1 provided with a light-emitting part 11 with a discharge space 111 inside, a metal halide 2 and a rare gas sealed in the discharge space 111, and a pair of electrodes 32 disposed so that the tip ends of the respective electrodes 32 face each other in the discharge space 111. The electrodes 32 and the discharge space 111 do not contain thorium. When an electric power supplied to the lamp during a stable lighting period is represented by P (W), a value obtained by adding up the electric power supplied to the lamp during a period between 1 second and 40 seconds after the startup of the lamp is represented by WL (W), and the diameter of the electrodes 32 is represented by D (mm), P (W) satisfies 20≦P≦30 and WL/D (W/mm) satisfies 4300≦WL/D≦7400.

Dependencies are inferred from the claim text.