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AssigneeKoninklijke Philips Electronics N.V.
InventorsPeter J. Schmidt, Walter Mayr, Joerg Meyer, Wolfgang Schnick, Cora Sieglinde Hecht, Florian Stadler
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The invention relates to an improved red light emitting material of the formula M1−yA1+xSi4−xN7−x−2yOx+2y:RE whereby M is selected out of the group comprising Ba, Sr, Ca, Mg or mixtures thereof, A is selected out of the group comprising Al, Ga, B or mixtures thereof, RE is selected out of the group comprising rare earth metals, Y, La, Sc or mixtures thereof and x is ≧0 and ≦1 and y is ≧0 and ≦0.2. This material is believed to crystallize in a novel structure type that comprises two individual lattice sites for rare earth metal incorporation, which leads to an improved lighting behaviour.
A light emitting device comprising:
Dependencies are inferred from the claim text.
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Containing two or more rare earth metals: aluminates
Based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides: based on silicon nitride
Based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides: based on silicon oxynitride, e.g. SIALONS
Containing europium: silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
About 3 years 3 months of term left · ends 5 Feb 2030 (estimated)
The present invention is directed to novel luminescent materials for light emitting devices, especially to the field of novel luminescent materials for LEDs and their use in light emitting devices. The invention also relates to a light emitting device comprising such material and a system comprising light emitting devices.
Phosphors comprising silicates, phosphates (for example, apatite) and aluminates as host materials, with transition metals or rare earth metals added as activating materials to the host materials, are widely known. As blue LEDs, in particular, have become practical in recent years, the development of white light sources utilizing such blue LEDs in combination with such phosphor materials is being energetically pursued.
Especially red emitting luminescent materials have been in the focus of interest and several materials have been proposed, e.g. U.S. Pat. No. 6,680,569(B2), “Red Deficiency Compensating Phosphor for a Light Emitting Device”, or from WO patent application 2005/052087 A1.
Additional details, features, characteristics and advantages of the object of the invention are disclosed in the subclaims, the figures and the following description of the respective figures and examples, which—in an exemplary fashion—show several embodiments and examples of a at least one ceramic material for use in a light emitting device according to the invention as well as several embodiments and examples of a light emitting device according to the invention.
FIG. 1 shows a schematic perspective partial view of a structure of a host material according to a first example of the present invention;
FIG. 2 shows the structure of FIG. 1 from a further perspective.
The invention will be further understood by the following Examples I and II which—in a merely illustrative fashion—shows several materials of the present invention.
FIGS. 1 to 4 refer to SrAlSi4N7:Eu(2%) which was made according to the following:
SrAlSi4N7:Eu(2%) was prepared by mixing Sr metal powder (0.49 mol, 42.9 g), Eu metal powder (0.01 mol, 1.52 g), Si3N4 (grain size <500 nm; 0.67 mol, 93.5 g) and AlN (1.0 mol, 41.0 g). The educts are heated in dry N2 atmosphere in tungsten crucibles according to the following heating profile: