| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an arc tube for discharging bulb of which the light distribution control depending on the shape of a reflector is easily, compactly formed by constructing the arc tube with a translucent ceramic excellent in heat resistance and durability. <P>SOLUTION: The arc tube for discharging bulb comprises electrodes facing each other formed by sealing electrode rods at both ends of a light emitting tube 12 and inboard electrode of arc tube 12 is oppositely-installed, and sealed space 12a in which light emitting material is sealed together with rare gas for starting. The light emitting tube 12 is made of nearly cylinder-shaped translucent ceramic excellent in heat resistance and durability, and compactly formed on condition that the ratio of outer diameter d to the whole length L, d/L, ranges between 0.2 to 0.5. Whole part of the light emitting tube 12 is made to uniformly emit light by making the parallel light transmissivity of the light emitting tube 20% or less, and total light transmissivity of the same 85% or more to obtain a rod-shaped light emitting part without unevenness of brightness and color. In the case of using the arc tube as a discharging bulb serving as a light source of a reflection type lighting equipment, the light distribution control depending on the shape of a reflector face becomes easy, and a proper light distribution of bright white color can be formed. <P>COPYRIGHT: (C)2004,JPO |
