Patent ID: 7965042

Claim:
A metal halide lamp comprising: an outer tube; an inner tube made of quartz glass that is provided in the outer tube and has a sealing portion formed of a collapsed open end portion in one end portion thereof and a tip-off portion in another end portion thereof, the inner tube forming an enclosed area that has hermeticity; and an arc tube provided in the inner tube, the arc tube including an envelope made of translucent ceramic, wherein a longitudinal central axis of the outer tube, a longitudinal central axis of the inner tube, and a longitudinal central axis of the arc tube are substantially coaxial, and assuming that the outer tube has a maximum outer diameter A (mm), the inner tube has a maximum outer diameter B (mm), and the metal halide lamp consumes P (W) of power, the following relationships are satisfied: 0.06 P +15.8 <A < 25, 0.05 P +9.0 <B , and 1.14 <A/B, where P satisfies 20<P<130.