GB746065A - Luminescent material, particularly for electric discharge lamps and method for its manufacture - Google Patents

Abstract

746,065. Luminescent materials. PATENTTREUHAND-GES. FUR ELEKTRISCHE GLUHLAMPEN. Sept. 17, 1953 [Oct. 11, 1952], No. 25725/53. Drawings to Specification. Class 39 (1). A luminescent material excited by ultraviolet corpuscular or X-radiation, particularly for use as an imier or outer coating on a discharge lamp or on a screen in front of the lamp, consists of a complex compound of alkaline earth fluorides, alkaline earth silicates and/or germanates with an addition of titanium and is prepared by firing under exclusion of moisture. The firing preferably takes place in an oxidizing atmosphere such as dry oxygen. The titanium, amounts to about 0.001-30 per cent by weight and manganese may be added to the amount of 0.001-5 per cent by weight. In one example a mixture of MgF 2 , MgO and SiO 2 in a mol.- proportion of about 1: 1: 1, and 1-3 per cent, preferably 1.7 per cent, of TiO 2 is fired at more than about 800‹ C., preferably at about 1150‹ C., for about 1 to 2 hours under exclusion of moisture and preferably in an atmosphere of dry oxygen. 0.2 per cent of Mn in the form of MnCO 3 can be added to the mixture. In another example BaF 2 and BaCO 3 can replace the magnesium compounds. The luminescent material can be mixed with halo-phosphates and/or alkaline earth silicates. The luminescent material can be used in a discharge lamp with incandescent or cold sheet electrodes and filled with argon and mercury. Specification 714,057 is referred to.