| 摘要 |
PURPOSE:To enable light to be homogeneously radiated toward the circumference direction and enable a stable optical output to be obtained by specifying the current density of the emission tube as well as the height and the angle of the electrodes. CONSTITUTION:The current density of an emission tube 1 is adjusted to be at least 2.0A/cm<2> and the height of sealed electrodes 2 and 2' is adjusted to be at least 6.0mm.. The central axis (B-B') of the electrodes 2 and 2' and the central axis (A-A') of the emission tube 1 are located at an angle of 5-30 deg. on a vertical surface, thereby constituting a horizontal metal halide lamp. Because of the above constitution, when the metal halide lamp is ignited in the horizontal position, an excess of an iodide (during the ignition) stably aggregates in the positions of sealing areas 11 thereby preventing any abrupt variations of the optical output. Furthermore, any excess of the charged material does not adhere to the part of the inner surface of the emission tube 1 located between the free ends of the electrodes 2 and 2' thereby achieving a stable homogeneous optical output. |
