| 摘要 |
PURPOSE:To obtain a proper luminance distribution at any time when an upper lamp or a lower lamp is lighted, and to suppress a decrease in efficiency when two lamps are lighted by setting the focus of the reflector of a lighting device within a predetermined range so as to cut the shading angle at 30 degrees while narrowing the opening width of the lighting device. CONSTITUTION:A focus K of reflectors 7, 8 is set at the middle point of the center H1 of an upper lamp 3 and the center of the lower lamp 5, and the reflectors 7, 8 are set with their parabolic axis rotated by 30 degrees from the vertical axis. Luminous flux of both reflected light and direct light below the shading angle of 30 degrees are cut during the lower lamp is lighted, and luminous flux of both reflected light and direct light below 50 degrees are cut during the upper lamp is lighted. Thus, a proper luminance distribution is obtained when the upper or the lower lamp is lighted, and the decrease in the efficiency is suppressed when both lamps are lighted. |
