这项发明涉及的是 Eu~(3+)激活的碱土金属和稀土金属硅酸盐。这项发明也涉及用这种硅酸盐制备的发光层和用种发光层制备的低压汞灯.由卤化物构成的碱土金属和稀土金属硅酸盐已在美国专利3.650,974中作了报导。这种卤化物具有磷灰石结构。钙钇氟化物硅酸盐可以看作为 Eu~(3+)激活材料的一个实例,用紫外线激发,这种 Eu~(3+)激活的硅酸盐发射典型的 Eu~(3+)红色发光。但是这种硅酸盐的光输出明显地低于 Eu~(3+)激活的 Y_2O_3。 Eu~(3+)激活的 Y_2O_3是非常有效的红色发光材料, This invention relates to Eu ~ (3 +) activated alkaline earth metal and rare earth metal silicates. This invention also relates to a light-emitting layer prepared using such a silicate and a low-pressure mercury lamp made from a light-emitting layer. Alkaline earth and rare earth silicates composed of halides have been reported in U.S. Patent 3.650,974 . This halide has an apatite structure. Calcium yttrium fluoride silicate can be seen as an example of Eu ~ (3 +) active material, excited by ultraviolet light, this Eu ~ (3 +) activated silicate emits typical Eu ~ (3+) red luminescence . However, the light output of this silicate is significantly lower than that of Eu 3+ -activated Y 2 O 3. Eu 3+ activated Y 2 O 3 is a very effective red luminescent material,