| 摘要 |
PURPOSE:To improve the color rendering properties of a lamp, by making small the whole surface area of a light emitting tube end composed of a translucent ceramic. CONSTITUTION:At both ends of a pipe 1 composed of a translucent alumina (aluminum oxide), an end disk 3 provided with both of an electrode 2 and an exhaust pipe 4 is sealed up, making up a light emitting tube. Inside this light emitting tube, a proper amount of Na, Ga and Xe gasses is sealed inside. And, the light emitting tube is constituted so as to make such a relationship as S/Z< 12 come into existence between the surface area S and tube wall load Z of a light emitting tube end being defined as the whole surface area in an arrow A-A' direction whereby an average color rendering rating Ra of a high pressure sodium lamp in below 100W could reach to more than 80. |
