| 摘要 |
505,697. Metal-vapour lamps. GENERAL ELECTRIC CO., Ltd. (Patent-Treuhand-Ges. f³r Electrische Gl³hlampen) Feb. 10, 1938, No. 4205. Addition to 466,503. [Class 39 (i)] In low pressure mercury vapour discharge apparatus in which the discharge excites to luminescence a material consisting mainly of activated cadmium silicate as described in the parent Specification, the cadmium silicate is activated by manganese, and is mixed with calcium . tungstate activated by 1-1 per cent of samarium. The amount of calcium tungstate is preferably 20-35 per cent by weight of the cadmium silicate. With a low pressure discharge operated at a current density of 100-500 mA/cm<3>., the material may be disposed on the interior surface of the envelope and gives approximately white light. With a current density of less than 100 mA/cm<2>., the ratio of light from the luminescent material will be greater, and the interposition of a yellow filter, such as by making the envelope of yellow glass, will result in an emitted light of golden-yellow colour. Specification 460,756, [Group XX], is referred to. |
