| 摘要 |
PURPOSE:To suppress the stray light by guiding the electric discharge around a cathode to the required discharge paths in a bulb with discharge partition members. CONSTITUTION:When an electric discharge is generated by an anode 31a and a cathode 21, the lateral diffusion of the glow around the cathode 21 is prevented by a diffusion preventing body 23. The discharge diameter of the glow around the cathode 21 is squeezed by the center hole 24 of the preventing body 25 and guided to discharge voltage partition plates 28a1-b2 and guided through the lower end of the parallel discharge path 29a of a reflecting cylinder 26, and the diffusion of the electric discharge to discharge paths 29b-d is suppressed. Even if the glow is leaked from the hole 24 to other discharge paths, the partition plates 28a1-b2 are not coated with a phosphor, thus the conversion from ultraviolet rays to visible rays is rarely performed, and the stray light can be suppressed. A positive column is formed by the electric discharge passing the discharge path 29a to generate ultraviolet rays end excite a phosphor film 30, and the light with the required color is illuminated. Since the glow is not diffused to the discharge paths 29b-d, only the discharge path 29a is illuminated, and the stray light is suppressed.
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