| 摘要 |
<p>In the conventional discharge lamp for an automotive vehicle, since an optical distortion is generated in an arc shape at a time of passing through a discharge chamber portion and a shining portion is generated in a seal portion, a light distribution is not suitably controlled at a time of assembling a light equipment, so that there is a problem that a formation of the light distribution becomes difficult. In accordance with a discharge lamp (1) for an automotive vehicle of the present invention, a taper portion (22a) is provided in a seal portion (22), a discharge chamber portion (21) is structured such that a curvature of a tube wall in a region of an angle 45 degrees to both sides from a plane X perpendicular to a tube axis Z as seen from a position of a center P of the discharge chamber portion (21) is substantially constant, a ratio of a thickness of the tube wall within the above range is set to be a value within a range from 1 to 0.8, and a discharge bulb (2) and an outer cover tube (6) are in contact with each other in the lowermost portion of the discharge chamber portion (21), the other portion than the arc portion is prevented from shining in the taper portion provided in the seal portion, by specifying the shape of the discharge chamber portion, an optical distortion at a time of passing through the discharge bulb can be reduced, and by bringing the discharge bulb and the outer cover tube into contact with each other, a non-evaporated metal halide material can be stored in the narrow range. <IMAGE></p> |
