GARNET-TYPE FLUORESCENT POWDER, PREPARATION METHOD AND DEVICES COMPRISING THE FLUORESCENT POWDER

Abstract

The application relates to fluorescent powder which has a garnet structure and can be effectively excited by ultraviolet light or blue light, a method for preparing the fluorescent powder, and a light emitting device, an image display device and an illumination device comprising the fluorescent powder. A chemical formula of the fluorescent powder is expressed as: (M.sup.1a-xM.sup.2x)ZrbM.sup.3cOd, where M.sup.1 is one or two elements selected from Sr, Ca, La, Y, Lu and Gd, Ca or Sr being necessary; M.sup.2 is one or two elements selected from Ce, Pr, Sm, Eu, Tb and Dy, Ce being necessary; M.sup.3 is at least one element selected from Ga, Si, and Ge, Ga being necessary; and 2.8≦a≦3.2, 1.9≦b≦2.1, 2.8≦c≦3.2, 11.8≦d≦12.2, and 0.002≦x≦0.6.

Claims

1-14. (canceled)

15. A fluorescent powder, wherein the fluorescent powder has a garnet crystal structure, and a chemical formula of the fluorescent powder is expressed as: (M.sup.1.sub.a-xM.sup.2.sub.x)Zr.sub.bM.sup.3.sub.cO.sub.d, wherein M.sup.1 is one or two elements selected from Sr, Ca, La, Y, Lu and Gd, Ca or Sr being necessary; M.sup.2 is one or two elements selected from Ce, Pr, Sm, Eu, Tb and Dy, Ce being necessary; M.sup.3 is at least one element selected from Ga, Si, and Ge, Ga being necessary; and 2.8≦a≦3.2, 1.9≦b≦2.1, 2.8≦c≦3.2, 11.8≦d≦12.2, and 0.002≦x≦0.6.

16. The fluorescent powder according to claim 15, wherein an atom number ratio m of (Ca+Sr) to M.sup.1 is: 2/3≦m≦1.

17. The fluorescent powder according to claim 15, wherein an atom number ratio n of Ce to M.sup.2 is: 0.8≦n≦1.

18. The fluorescent powder according to claim 17, wherein an atom number ratio k of Ga to M.sup.3 is: 2/3≦k≦1.

19. The fluorescent powder according to claim 15, wherein M.sup.1 in the fluorescent powder comprises Ca.

20. The fluorescent powder according to claim 15, wherein a:b:c:d is 3:2:3:12.

21. The fluorescent powder according to claim 15, wherein when M.sup.1 comprises Ca, an atom number ratio m of Ca to M.sup.1 is: 2/3≦m≦1; and when M.sup.1 comprises Sr and does not comprise Ca, an atom number ratio m of Sr to M.sup.1 is: 2/3≦m≦1.

22. A method for preparing the fluorescent powder according to claim 15, comprising the following steps: (1) serving compounds corresponding to M.sup.1, M.sup.2, M.sup.3 and Zr as raw materials and egrounding and unifromly mixing the compounds; (2) roasting a mixture obtained in Step (1) in a reducing atmosphere at high temperatures; and (3) after-treating a roasted product obtained in Step (2), and the fluorescent powder is obtained.

23. The method according to claim 22, wherein in Step (1), the compounds corresponding to M.sup.1, M.sup.2, M.sup.3 and Zr comprise oxides, carbonates, oxalates and nitrates.

24. The method according to claim 22, wherein in Step (2), the roasting is performed for one or several times, temperatures of the roasting range from 1,100° C.˜1,400° C. at each time, and the roasting lasts for 0.5 h to 20 h at each time.

25. The method according to claim 24, wherein in Step (3), the after-treating comprises crushing, grinding or/and classifying.

26. A light emitting device, comprising a light source and fluorescent powder, wherein at least one kind of fluorescent powder is selected from the fluorescent powder according to claim 15.

27. The fluorescent powder according to claim 16, wherein an atom number ratio n of Ce to M.sup.2 is: 0.8≦n≦1.

28. The method according to claim 23, wherein in Step (2), the roasting is performed for one or several times, temperatures of the roasting range from 1,100° C.˜1,400° C. at each time, and the roasting lasts for 0.5 h to 20 h at each time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings of the specification, forming a part of the application, are intended to provide further understanding of the application. The schematic embodiments and illustrations of the application are intended to explain the application, and do not form improper limits to the application. In the drawings:

[0048] FIG. 1 is an X-powder diffraction diagram of (Ca.sub.2La.sub.0.96,Ce.sub.0.04)Zr.sub.2Ga.sub.3O.sub.12;

[0049] FIG. 2 is an excitation spectrum diagram of (Ca.sub.2La.sub.0.96,Ce.sub.0.04)Zr.sub.2Ga.sub.3O.sub.12;

[0050] FIG. 3 is an emission spectrum diagram of (Ca.sub.2La.sub.0.96,Ce.sub.0.04)Zr.sub.2Ga.sub.3O.sub.12;

[0051] FIG. 4 is an X-powder diffraction diagram of (Ca.sub.2.91,Ce.sub.0.06)Zr.sub.2(Ga.sub.2Ge)O.sub.12;

[0052] FIG. 5 is an excitation spectrum diagram of (Ca.sub.2.91,Ce.sub.0.06)Zr.sub.2(Ga.sub.2Ge)O.sub.12;

[0053] FIG. 6 is an emission spectrum diagram of (Ca.sub.2.91,Ce.sub.0.06)Zr.sub.2(Ga.sub.2Ge)O.sub.12; and

[0054] FIG. 7 is an X-powder diffraction refinement pattern of (Ca.sub.2Y.sub.0.94, Ce.sub.0.06)Zr.sub.2Ga.sub.3O.sub.12.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The following further illustrations of the embodiments for fluorescent powder of the application and a preparation method thereof will contribute to further understanding of the application. A protective range of the application is not limited by these embodiments, and the protective range thereof is decided by the claims.

[0056] Comparing Sample

[0057] 0.2 mol of CaCO.sub.3, 0.05 ml of La.sub.2O.sub.3, 0.2 mol of ZrO.sub.2 and 0.15 mol of Ga.sub.2O.sub.3 are weighed according to a chemical formula (Ca.sub.2La)Zr.sub.2Ga.sub.3O.sub.12. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 4 h at the temperature of 1,350° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain a compound having a composition: (Ca.sub.2La)Zr.sub.2Ga.sub.3O.sub.12. A sample is extracted for spectrum test, an emission spectrum being not seen under the excitation of ultraviolet and blue-light areas. The relative luminous intensity under the excitation of 420 nm is 0, as shown in Table 3.

Embodiment 1

[0058] 0.2 mol of CaCO.sub.3, 0.048 ml of La.sub.2O.sub.3, 0.2 mol of ZrO.sub.2, 0.15 mol of Ga.sub.2O.sub.3 and 0.004 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2La.sub.0.96,Ce.sub.0.04)Zr.sub.2Ga.sub.3O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 4 h at the temperature of 1,350° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2La.sub.0.96,Ce.sub.0.04)Zr.sub.2Ga.sub.3O.sub.12. An X-powder diffraction diagram (Co target, λ=0.178892 nm) thereof is shown in FIG. 1. An excitation spectrum (515 nm monitoring) and an emission spectrum (420 nm excitation) thereof are shown in FIG. 2 and FIG. 3. From the drawings, it can be obtained that an excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 515 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 2

[0059] 0.291 mol of CaCO.sub.3, 0.2 mol of ZrO.sub.2, 0.1 mol of GeO.sub.2, 0.1 mol of Ga.sub.2O.sub.3 and 0.006 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2.91,Ce.sub.0.06)Zr.sub.2(Ga.sub.2Ge)O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 8 h at the temperature of 1,320° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2.91,Ce.sub.0.06)Zr.sub.2(Ga.sub.2Ge)O.sub.12. An X-powder diffraction diagram (Co target, λ=0.178892 nm) thereof is shown in FIG. 4. An excitation spectrum (475 nm monitoring) and an emission spectrum (420 nm excitation) thereof are shown in FIG. 5 and FIG. 6. From the drawings, it can be obtained that an excitation wavelength range covers 280 to 440 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 475 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 3

[0060] 0.2 mol of CaCO.sub.3, 0.2 mol of ZrO.sub.2, 0.047 mol of Y.sub.2O.sub.3, 0.15 mol of Ga.sub.2O.sub.3 and 0.006 mol of Ce(NO.sub.3).sub.3 are weighed according to a chemical formula (Ca.sub.2Y.sub.0.94,Ce.sub.0.06)Zr.sub.2Ga.sub.3O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 6 h at the temperature of 1,360° C. in an H.sub.2/N.sub.2 mixed atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2Y.sub.0.94,Ce.sub.0.06)Zr.sub.2Ga.sub.3O.sub.12. X-powder ray diffraction refinement fitting parameters thereof are shown in Table 1 and Table 2. Fitting of a pattern is shown in FIG. 7. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 512 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 4

[0061] 0.2 mol of CaCO.sub.3, 0.2 mol of ZrO.sub.2, 0.046 mol of Lu.sub.2O.sub.3, 0.15 mol of Ga.sub.2O.sub.3 and 0.008 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2Lu.sub.0.92,Ce.sub.0.08)Zr.sub.2Ga.sub.3O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 4 h at the temperature of 1,100° C. in air. A roasted product is crushed and then secondarily roasted for 6 h at the sintering temperature of 1,350° C. in a CO atmosphere. A secondarily roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2Lu.sub.0.92,Ce.sub.0.08)Zr.sub.2Ga.sub.3O.sub.12. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 502 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 5

[0062] 0.2 mol of CaCO.sub.3, 0.045 mol of Gd.sub.2O.sub.3, 0.2 mol of ZrO.sub.2, 0.15 mol of Ga.sub.2O.sub.3 and 0.01 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2Gd.sub.0.9,Ce.sub.0.1)Zr.sub.2Ga.sub.3O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 6 h at the temperature of 1,400° C. in an H.sub.2/N.sub.2 mixed atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2Gd.sub.0.9,Ce.sub.0.1)Zr.sub.2Ga.sub.3O.sub.12. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 514 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 6

[0063] 0.275 mol of CaCO.sub.3, 0.01 mol of SrCO.sub.3, 0.2 mol of ZrO.sub.2, 0.02 mol of SiO.sub.2, 0.1 mol of Ga.sub.2O.sub.3, 0.08 mol of GeO.sub.2 and 0.01 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2.75Sr.sub.0.1,Ce.sub.0.1)Zr.sub.2(Ga.sub.2Ge.sub.0.8Si.sub.0.2)O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 0.5 h at the temperature of 1,200° C. in air. A primarily roasted product is crushed and then secondarily roasted for 6 h at the sintering temperature of 1,320° C. in a CO atmosphere. A secondarily roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2.75Sr.sub.0.1,Ce.sub.0.1)Zr.sub.2(Ga.sub.2Ge.sub.0.8Si.sub.0.2)O.sub.12. An excitation wavelength range covers 280 to 460 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 482 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 7

[0064] 0.25 mol of CaCO.sub.3, 0.0225 mol of Lu.sub.2O.sub.3, 0.2 mol of ZrO.sub.2, 0.05 mol of SiO.sub.2, 0.125 mol of Ga.sub.2O.sub.3, 0.0005 mol of Eu.sub.2O.sub.3 and 0.004 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2.5Lu.sub.0.45,Ce.sub.0.04Eu.sub.0.01)Zr.sub.2(Ga.sub.2.5Si.sub.0.5)O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 8 h at the temperature of 1,400° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2.5Lu.sub.0.45,Ce.sub.0.04Eu.sub.0.01)Zr.sub.2(Ga.sub.2.5Si.sub.0.5)O.sub.12. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 493 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 8

[0065] 0.2997 mol of CaCO.sub.3, 0.2 mol of ZrO.sub.2, 0.1 mol of SiO.sub.2, 0.1 mol of Ga.sub.2O.sub.3 and 0.0002 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2.997,Ce.sub.0.002)Zr.sub.2(Ga.sub.2Si)O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 4 h at the temperature of 1,380° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2.997,Ce.sub.0.002)Zr.sub.2(Ga.sub.2Si)O.sub.12. An excitation wavelength range covers 280 to 450 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 487 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 9

[0066] 0.24 mol of CaCO.sub.3, 0.19 mol of ZrO.sub.2, 0.0375 mol of Y.sub.2O.sub.3, 0.14 mol of Ga.sub.2O.sub.3, 0.004 mol of CeO.sub.2 and 0.00017 mol of Pr.sub.6O.sub.11 are weighed according to a chemical formula (Ca.sub.2.4Y.sub.0.75,Ce.sub.0.04Pr.sub.0.01)Zr.sub.1.9Ga.sub.2.8O.sub.11.8 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, carbon powder is added, and an obtained mixture is roasted for 15 h at the temperature of 1,350° C. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2.4Y.sub.0.75,Ce.sub.0.04Pr.sub.0.01)Zr.sub.1.9Ga.sub.2.8O.sub.11.8. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 510 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 10

[0067] 0.2 mol of SrCO.sub.3, 0.035 mol of Gd.sub.2O.sub.3, 0.21 mol of ZrO.sub.2, 0.16 mol of Ga.sub.2O.sub.3, 0.008 mol of CeO.sub.2 and 0.001 mol of Dy.sub.2O.sub.3 are weighed according to a chemical formula (Sr.sub.2Gd.sub.0.7,Ce.sub.0.08Dy.sub.0.02)Zr.sub.2.1Ga.sub.3.2O.sub.12.2 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 20 h at the temperature of 1,400° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Sr.sub.2Gd.sub.0.7,Ce.sub.0.08Dy.sub.0.02)Zr.sub.2.1Ga.sub.3.2O.sub.12.2. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 526 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 11

[0068] 0.294 mol of SrCO.sub.3, 0.1 mol of SiO.sub.2, 0.2 mol of ZrO.sub.2, 0.1 mol of Ga.sub.2O.sub.3 and 0.004 mol of CeO.sub.2 are weighed according to a chemical formula (Sr.sub.2.94,Ce.sub.0.04)Zr.sub.2(Ga.sub.2Si)O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 6 h at the temperature of 1,300° C. in air. A roasted product is crushed and then secondarily roasted for 10 h at the sintering temperature of 1,400° C. in a CO/N.sub.2 atmosphere. A secondarily roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Sr.sub.2.94,Ce.sub.0.04)Zr.sub.2(Ga.sub.2Si)O.sub.12. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 494 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 12

[0069] 0.2 mol of SrCO.sub.3, 0.2 mol of ZrO.sub.2, 0.0475 mol of La.sub.2O.sub.3, 0.15 mol of Ga.sub.2O.sub.3 and 0.005 mol of CeO.sub.2 are weighed according to a chemical formula (Sr.sub.2La.sub.0.95,Ce.sub.0.05)Zr.sub.2Ga.sub.3O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 6 h at the temperature of 1,200° C. in air. A roasted product is crushed and then secondarily roasted for 2 h at the sintering temperature of 1,370° C. in an H.sub.2/N.sub.2 atmosphere. A secondarily roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Sr.sub.2La.sub.0.95,Ce.sub.0.005)Zr.sub.2Ga.sub.3O.sub.12. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 535 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 13

[0070] 0.2 mol of CaCO.sub.3, 0.2 mol of ZrO.sub.2, 0.02 mol of Y.sub.2O.sub.3, 0.15 mol of Ga.sub.2O.sub.3, 0.05 mol of CeO.sub.2 and 0.0025 mol of Tb.sub.4O.sub.7 are weighed according to a chemical formula (Ca.sub.2Y.sub.0.4,Ce.sub.0.5Tb.sub.0.1)Zr.sub.2Ga.sub.3O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 4 h at the temperature of 1,350° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2Y.sub.0.4,Ce.sub.0.5Tb.sub.0.1)Zr.sub.2Ga.sub.3O.sub.12. An excitation wavelength range covers 280 to 450 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 542 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 14

[0071] 0.28 mol of CaCO.sub.3, 0.2 mol of ZrO.sub.2, 0.08 mol of SiO.sub.2, 0.008 mol of Gd.sub.2O.sub.3, 0.11 mol of Ga.sub.2O.sub.3 and 0.004 mol of CeO.sub.2 are weighed according to a chemical formula (Ca.sub.2.8Gd.sub.0.16,Ce.sub.0.04)Zr.sub.2(Ga.sub.2.2Si.sub.0.8)O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 6 h at the temperature of 1,320° C. in a CO atmosphere. A roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Ca.sub.2.8Gd.sub.0.16,Ce.sub.0.04)Zr.sub.2(Ga.sub.2.2Si.sub.0.8)O.sub.12. An excitation wavelength range covers 280 to 450 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 492 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 15

[0072] 0.22 mol of SrCO.sub.3, 0.2 mol of ZrO.sub.2, 0.02 mol of SiO.sub.2, 0.0365 mol of La.sub.2O.sub.3, 0.14 mol of Ga.sub.2O.sub.3, 0.005 mol of CeO.sub.2 and 0.001 mol of Sm.sub.2O.sub.3 are weighed according to a chemical formula (Sr.sub.2.2La.sub.0.73,Ce.sub.0.05Sm.sub.0.02)Zr.sub.2(Ga.sub.2.8Si.sub.0.2)O.sub.12 of fluorescent powder. After these raw materials are fully ground and uniformly mixed, an obtained mixture is roasted for 6 h at the temperature of 1,200° C. in air. A roasted product is crushed and then secondarily roasted for 2 h at the sintering temperature of 1,380° C. in an H.sub.2/N.sub.2 atmosphere. A secondarily roasted product is after-treated, including crushing, classifying, washing, drying, sieving and the like to obtain fluorescent powder having a composition: (Sr.sub.2.2La.sub.0.73,Ce.sub.0.05Sm.sub.0.02)Zr.sub.2(Ga.sub.2.8Si.sub.0.2)O.sub.12. An excitation wavelength range covers 280 to 480 nm, under the 420 nm excitation, the peak wavelength of the emission spectrum is 524 nm, and the relative luminous intensity is shown in Table 3.

Embodiment 16

[0073] Green fluorescent powder obtained in Embodiment 1 and red powder of K.sub.2SiF.sub.6:Mn are scattered in resin in a ratio of 7:1, and after being mixed, the slurry is coated on a 450 nm blue-light LED chip, solidified, welded to a circuit and sealed by the resin to obtain a light emitting device emitting white light, the chromaticity coordinate being (0.3885, 0.3692), the colour rendering index being 87.2, and the correlated colour temperature being 3624K.

Embodiment 17

[0074] Blue fluorescent powder obtained in Embodiment 2, β-SiAlON:Eu green fluorescent powder and CaAlSiN.sub.3:Eu red fluorescent powder are scattered in resin in a ratio of 3:6:1, and after being mixed, the slurry is coated on a 405 nm ultraviolet LED chip, solidified, welded to a circuit and sealed by the resin to obtain a light emitting device emitting white light, the chromaticity coordinate being (0.3963, 0.3785), and the colour reproduction range being 80% NTSC.

Embodiment 18

[0075] Blue fluorescent powder obtained in Embodiment 7, green fluorescent powder obtained in Embodiment 13 and (Sr,Ca).sub.2Si.sub.5N.sub.8:Eu red fluorescent powder are scattered in resin in a ratio of 4:7:1, and after being mixed, the slurry is coated on a 405 nm ultraviolet LED chip, solidified, welded to a circuit and sealed by the resin to obtain a light emitting device emitting white light, the chromaticity coordinate being (0.3796, 0.3589), the colour rendering index being 85.6, and the correlated colour temperature being 4230K.

TABLE-US-00003 TABLE 3 Chemical formulae of comparing example and Embodiments 1-15, and emission main peak position and relative luminous intensity under 420 nm excitation (the luminous intensity of Ca.sub.2La.sub.0.96Zr.sub.2Ga.sub.3O.sub.12:Ce.sub.0.04 is selected to be 100% under the 420 nm excitation) Emission Relative main peak luminous Chemical formula of fluorescent position intensity Serial number powder (nm) (%) Comparing (Ca.sub.2La)Zr.sub.2Ga.sub.3O.sub.12 Null 0 example Embodiment 1 (Ca.sub.2La.sub.0.96,Ce.sub.0.04)Zr.sub.2Ga.sub.3O.sub.12 515 100 Embodiment 2 (Ca.sub.2.91,Ce.sub.0.06)Zr.sub.2(Ga.sub.2Ge)O.sub.12 475 112 Embodiment 3 (Ca.sub.2Y.sub.0.94,Ce.sub.0.06)Zr.sub.2Ga.sub.3O.sub.12 512 105 Embodiment 4 (Ca.sub.2Lu.sub.0.92,Ce.sub.0.08)Zr.sub.2Ga.sub.3O.sub.12 502 101 Embodiment 5 (Ca.sub.2Gd.sub.0.9,Ce.sub.0.1)Zr.sub.2Ga.sub.3O.sub.12 514 102 Embodiment 6 (Ca.sub.2.75Sr.sub.0.1,Ce.sub.0.1)Zr.sub.2(Ga.sub.2Ge.sub.0.8Si.sub.0.2)O.sub.12 482 95 Embodiment 7 (Ca.sub.2.5Lu.sub.0.45,Ce.sub.0.04Eu.sub.0.01)Zr.sub.2(Ga.sub.2.5Si.sub.0.5)O.sub.12 493 107 Embodiment 8 (Ca.sub.2.997,Ce.sub.0.002)Zr.sub.2(Ga.sub.2Si)O.sub.12 487 98 Embodiment 9 (Ca.sub.2.4Y.sub.0.75,Ce.sub.0.04Pr.sub.0.01)Zr.sub.1.9Ga.sub.2.8O.sub.11.8 510 102 Embodiment 10 (Sr.sub.2Gd.sub.0.7,Ce.sub.0.08Dy.sub.0.02)Zr.sub.2.1Ga.sub.3.2O.sub.12.2 526 96 Embodiment 11 (Sr.sub.2.94,Ce.sub.0.04)Zr.sub.2(Ga.sub.2Si)O.sub.12 494 103 Embodiment 12 (Sr.sub.2La.sub.0.95,Ce.sub.0.05)Zr.sub.2Ga.sub.3O.sub.12 535 96 Embodiment 13 (Ca.sub.2Y.sub.0.4,Ce.sub.0.5Tb.sub.0.1)Zr.sub.2Ga.sub.3O.sub.12. 542 106 Embodiment 14 (Ca.sub.2.8Gd.sub.0.16,Ce.sub.0.04)Zr.sub.2(Ga.sub.2.2Si.sub.0.8)O.sub.12 492 102 Embodiment 15 (Sr.sub.2.2La.sub.0.73,Ce.sub.0.05Sm.sub.0.02)Zr.sub.2(Ga.sub.2.8Si.sub.0.2)O.sub.12 524 97