| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a discharge valve effective to improve both of distributed illuminance (luminous intensity) and distant visibility of a headlamp for automobile. <P>SOLUTION: A discharge valve for automobile comprises a light emission tube body which has a discharge lighting room s in a ceramic tube 12, where electrodes 15 face each other and a luminescent material or the like is enclosed in the discharge lighting room s, and almost lower half of the outer periphery surface of the ceramic tube 12 is covered with a light shielding member 200. Since emitted light toward the lower side of the ceramic tube 12 is emitted from the upper side to proceed toward an effective reflection surface 101a of a reflector, the distributed illuminance of the headlamp is improved. Since a rectangular-shape light source image a projected (stuck) along a cutoff line becomes slim (narrow) in light distribution designing of a reflector 100, light distribution designing (designing of the effective reflection surface 101a) is performed so that a maximum luminance portion a1 approaches the cutoff line. This makes a hot zone approach a position of the cutoff line and the distant visibility improved. <P>COPYRIGHT: (C)2007,JPO&INPIT |
