| 摘要 |
PROBLEM TO BE SOLVED: To provide a light diffusion film 80 for obtaining light diffusion effects while reducing the deterioration of the light flux of a light diffusion cover 40 of a straight pipe type LED lamp.SOLUTION: In a light diffusion cover 40, a protective film 70 made of metallic oxide X(silica) is formed on the inner face of a glass tube 56, and a light diffusion film 80 is formed on the inner face of the protective film 70, and the light diffusion film 80 is constituted of a metallic oxide Y(silica) and a low-melting glass 83 which dissolves at a lower temperature than the dissolving temperature of the glass tube 56. The protective film 70 is constituted of metallic oxide X whose average particle diameters are ranging form 50 to 300nm, and the thickness of the protective film 70 is ranging from 0.5 to 5.0 μm. The light diffusion film 80 is constituted of metallic oxide Y whose average particle diameters are ranging from 50 to 20000nm and low melting glass 83, and the metallic oxide Y exists by the volume ratio of 30 to 50% with respect to the light diffusion film 80, and the thickness of the light diffusion film 80 is ranging from 5.0 to 20.0 μm. |
