| 摘要 |
1,205,340. Luminescent materials. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 22 July, 1968 [25 July, 1967], No. 34889/68. Heading C4S. A method of preparing a rare earth activated oxysulphide phosphor defined as A( 2-x )B x .O 2 S where A is Y, Gd or La, B is an element of atomic number 58 to 70 except 64 and 0À2 # x # 0.0002 comprises heating at 500‹-1500‹ C. for “-4 hours a dry mixture of an oxide of A and an oxide of B or a mixed oxide of A and B together with a compound or combination of substances which on heating yield a polysulphide of Na, K or Ba or the polysulphide, the polysulphide being molten at the heating temperature. Mixed oxides of Y and Tb, Y and Eu, Y and Er, La and Eu are heated with Na, K or Ba sulphide, sulphite, carbonate or oxalate and S or with thiosulphate or disulphide. The phosphor is washed to remove all impurities and may be reheated at 1100-1500‹ C. in N 2 or in air if C or ZnS is added to prevent oxidation of the oxysulphide, it is then washed in acetic acid. The phosphor is excited by U.V. light or electrons and used in lamps and C.R.T.s. |
