| 摘要 |
<p>Provided is an incandescent light bulb that includes a filament for which the efficiency of converting electric power to visible light is high. The incandescent light bulb has a translucent airtight container, a filament disposed in the translucent airtight container and a lead wire for supplying a current to the filament. The filament includes a base which is constituted by a first metallic material, and a metallic film which is constituted by a second metallic material and covers at least a part of the base. The melting point of the second metallic material that constitutes the metallic film is lower than the melting point of the first metallic material that constitutes the base. Therefore, high energy light (visible light) may be radiated in accordance with the bremsstrahlung of the metallic film that has a melting point lower than that of the base, and thus an incandescent light bulb that has high luminous flux efficiency for visible light can be acquired.</p> |
