| 摘要 |
The invention pertains to the field of lighting technology using InGaN-based blue LEDs and specifically to luminescent materials containing yttrium oxide, oxides of rare earth metals as well as aluminium oxide in proportions that yield a luminescent material whose average composition fits the general formula (Y 1-x-y Ce x ˆ‘Ln y ) 3+± Al 5 O 12+1,5± , where ± - defines increase in stoichiometric index over the known value for yttrium-gadolinium garnet and varies between 0.033 and 2; x - is atomic fraction of cerium, 0.0001-0.1; ˆ‘Ln y - is one or more lanthanides from the Gd, Tb, La, Yb group, whose atomic fraction in an yttrium sub-lattice is 0,01 <Gd< 0,70; 0,001<Tb<0,2; 0,001<La<0,1; 0,001<Yb<0,1 , respectively, while the difference for all the compositions [1-x-y] > 0. For stoichiometric index (3+±) varying between 3.034 and 3.45, the proposed material is a phase of cubic structure. The lighting characteristics of this phase for a given composition of rare earth elements do not depend significantly on the stoichiometric value whereas for a given stoichiometric index, spectral position of maximum can vary in the 550-590 nm range. This allows varying the colour temperature of white-light source between 2700 K and 5000 K. Over the 3.45 - 5 index range the proposed material is a two-phase compound in which for a given cation composition the lighting characteristics are determined by the value of (3+±) and the colour temperature of white-light source can vary between 3000 K and 6000 K depending on the composition. |
