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US 8,729,788 B2Granted
Light emitting device provided with a wavelength conversion unit incorporating plural kinds of phosphors
AssigneeSharp Kabushiki Kaisha
InventorsMasatsugu Masuda, Masaaki Katoh, Tsukasa Inoguchi
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Abstract
A light-emitting device includes a light-emitting element for emitting primary light, and a wavelength conversion unit for absorbing part of the primary light and emitting secondary light having a wavelength longer than that of the primary light, wherein the wavelength conversion unit includes plural kinds of phosphors having light absorption characteristics different from each other, and then at least one kind of phosphor among the plural kinds of phosphors has an absorption characteristic that can absorb the secondary light emitted from at least another kind of phosphor among the plural kinds of phosphors.
Claims6
A light-emitting device, comprising:
- a light-emitting element for emitting primary light;
- and
- a wavelength conversion unit for absorbing part of the primary light and emitting secondary lights having wavelengths longer than a wavelength of the primary light,
- wherein said wavelength conversion unit includes plural kinds of phosphors having different emission peak wavelengths and different median diameters that are in the order of several microns,
- the different median diameters are adjusted so that the plural kinds of phosphors have different settling speeds,
- the plural kinds of phosphors include a red phosphor for emitting red light and a green phosphor for emitting green light, and
- a concentration of the red phosphor adjacent the light-emitting element is higher than a concentration of the green phosphor adjacent the light-emitting element, and
- wherein said red phosphor for emitting red light includes a divalent europium-activated nitride phosphor represented by (MIII1-j,Euj)MIVSiN3, where MIII represents at least one kind of element selected from Mg, Ca, Sr and Ba, MIV represents at least one kind of element selected from Al, Ga, In, Sc, Y, La, Gd and Lu, and j represents a number satisfying 0.001≦j≦0.05;
- and
- said green phosphor for emitting green light includes at least one kind selected from
- a divalent europium-manganese co-activated aluminate phosphor represented by a(M2,Eue,Mnf)O.bAl2O3,
- a divalent europium-activated silicate phosphor represented by 2(M11-g,Eug)O.SiO2, and
- a trivalent cerium-activated silicate phosphor represented by MI3(MII1-h,Ceh)2(SiO4)3,
- where M2 represents at least one kind of element selected from Mg, Ca, Sr, Ba and Zn;
- a, b, e, and f represent numbers satisfying a>0, b>0, 0.1≦a/b≦1.0, and 0.3≦f/e≦5.0;
- M1 represents at least one kind of element selected from Mg, Ca, Sr and Ba;
- g represents a number satisfying 0.005≦g≦0.10;
- MI represents at least one kind of element selected from Mg, Ca, Sr and Ba;
- MII represents at least one kind of element selected from Al, Ga, In, Sc, Y, La, Gd and Lu;
- and h represents a number satisfying 0.005≦h≦0.5.
17 more elements
A light-emitting device, comprising:
- a light-emitting element for emitting primary light;
- and
- a wavelength conversion unit for absorbing part of the primary light and emitting secondary lights having wavelengths longer than a wavelength of the primary light,
- wherein the wavelength conversion unit includes plural kinds of phosphors having different emission peak wavelengths and different median diameters,
- the plural kinds of phosphors contain activators, and
- the different median diameters are adjusted so that the plural kinds of phosphors have different settling speeds,
- the plural kinds of phosphors include a red phosphor for emitting red light and a green phosphor for emitting green light, and
- a concentration of the red phosphor adjacent the light-emitting element is higher than a concentration of the green phosphor adjacent the light-emitting element, and
- wherein said red phosphor for emitting red light includes a divalent europium-activated nitride phosphor represented by (MIII1-j,Euj)MIVSiN3, where MIII represents at least one kind of element selected from Mg, Ca, Sr and Ba, MIV represents at least one kind of element selected from Al, Ga, In, Sc, Y, La, Gd and Lu, and j represents a number satisfying 0.001≦j≦0.05;
- and
- said green phosphor for emitting green light includes at least one kind selected from
- a divalent europium-manganese co-activated aluminate phosphor represented by a(M2,Eue,Mnf)O.bAl2O3,
- a divalent europium-activated silicate phosphor represented by 2(M11-g,Eue)O.SiO2, and
- a trivalent cerium-activated silicate phosphor represented by MI3(MII1-h,Ceh)2(SiO4)3,
- where M2 represents at least one kind of element selected from Mg, Ca, Sr, Ba and Zn;
- a, b, e, and f represent numbers satisfying a>0, b>0, 0.1≦a/b≦1.0, and 0.3≦f/e≦5.0;
- M1 represents at least one kind of element selected from Mg, Ca, Sr and Ba;
- g represents a number satisfying 0.005≦g≦0.10;
- MI represents at least one kind of element selected from Mg, Ca, Sr and Ba;
- MII represents at least one kind of element selected from Al, Ga, In, Sc, Y, La, Gd and Lu;
- and h represents a number satisfying 0.005≦h≦0.5.
18 more elements
A light-emitting device, comprising:
- a light-emitting element for emitting primary light;
- and
- a wavelength conversion unit for absorbing part of the primary light and emitting secondary lights having wavelengths longer than a wavelength of the primary light,
- wherein the wavelength conversion unit includes plural kinds of phosphors having different emission peak wavelengths and different median diameters,
- the emission peak wavelengths are independent of the median diameters, and
- the different median diameters are adjusted so that the plural kinds of phosphors have different settling speeds,
- the plural kinds of phosphors include a red phosphor for emitting red light and a green phosphor for emitting green light, and
- a concentration of the red phosphor adjacent the light-emitting element is higher than a concentration of the green phosphor adjacent the light-emitting element, and
- wherein said red phosphor for emitting red light includes a divalent europium-activated nitride phosphor represented by (MIII1-j,Euj)MIVSiN3, where MIII represents at least one kind of element selected from Mg, Ca, Sr and Ba, MIV represents at least one kind of element selected from Al, Ga, In, Sc, Y, La, Gd and Lu, and j represents a number satisfying 0.001≦j≦0.05;
- and
- said green phosphor for emitting green light includes at least one kind selected from
- a divalent europium-manganese co-activated aluminate phosphor represented by a(M2,Eue,Mnf)O.bAl2O3,
- a divalent europium-activated silicate phosphor represented by 2(M11-g,Eug)O.SiO2, and
- a trivalent cerium-activated silicate phosphor resented by MI3(MII1-h,Ceh)2(SiO4)3,
- where M2 represents at least one kind of element selected from Mg, Ca, Sr, Ba and Zn;
- a, b, e, and f represent numbers satisfying a>0, b>0, 0.1≦a/b≦1.0, and 0.3≦f/e≦5.0;
- M1 represents at least one kind of element selected from Mg, Ca, Sr and Ba;
- g represents a number satisfying 0.005≦g≦0.10;
- MI represents at least one kind of element selected from Mg, Ca, Sr and Ba;
- MII represents at least one kind of element selected from Al, Ga, In, Sc, Y, La, Gd and Lu;
- and h represents a number satisfying 0.005≦h≦0.5.
18 more elements
Dependencies are inferred from the claim text.