| 摘要 |
The wedge base bulb includes a bulb body having a colored glass bulb and a press-sealed portion. Further, a tubular insulation collar is mounted to cover press-sealed portion. Bulb body is formed in a process in that a molding section of a glass tube including a color-developing compound or a color-developing element is heat-melted under a reducing atmosphere in a predetermined temperature region, placed in a mold and expanded in the mold, and also develops color with colloid generated by the heat-melting. As a result, a wedge base bulb developed a color and chromaticity satisfying a predetermined standard can be provided at a lower cost.
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