Light emitting device, and lighting system, image display using the same
First Claim
1. A light emitting device, comprising:
- a mixture of a first phosphor, and a second phosphor that is different from the first phosphor; and
at least one semiconductor light emitting device that emits visible light;
wherein;
each of the first phosphor and the second phosphor is independently selected from the group consisting of oxides, oxynitrides and nitrides;
each of the first phosphor and the second phosphor has a luminous efficiency of 35% or higher when excited by the visible light from the semiconductor light emitting device at room temperature;
the second phosphor is capable of absorbing emitted light from the first phosphor;
the first phosphor is present in the mixture of phosphors in an amount of at least 85 weight %;
the second phosphor has the following formula (3);
MaAbDcEdXe
(3)wherein;
M is Eu and optionally at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb;
A is selected from the group consisting of bivalent metal elements other than M;
D is at least one element selected from the group consisting of tetravalent metal elements;
E is at least one element selected from the group consisting of trivalent metal elements;
X is at least one element selected from the group consisting of O, N, and F; and
a, b, c, d, and e satisfy the following conditions;
a+b=1;
0.00001≦
a≦
0.1;
0.5≦
c≦
1.8;
0. 5≦
d≦
1.8;
0.8×
(2/3+4/3×
c+d)≦
e; and
e≦
1.2×
(2/3+4/3×
c+d).
2 Assignments
0 Petitions
Accused Products
Abstract
To enhance luminance and color rendering of a light emitting device comprising phosphors as wavelength converting material and
at least one semiconductor light emitting device that emits visible light, as said phosphors, are used phosphors which are one or more kinds of phosphors selected from a group consisting of oxides, oxynitrides and nitrides, and are a mixture consisting of two or more kinds of phosphors whose luminous efficiency is 35% or higher when excited by the visible light from said semiconductor light emitting device at room temperature. In addition, said mixture contains a first phosphor, and a second phosphor that is different from said first phosphor and capable of absorbing emitted light from said first phosphor, and said first phosphor is contained 85 weight % or more of said mixture of phosphors.
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Citations
29 Claims
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1. A light emitting device, comprising:
-
a mixture of a first phosphor, and a second phosphor that is different from the first phosphor; and at least one semiconductor light emitting device that emits visible light; wherein; each of the first phosphor and the second phosphor is independently selected from the group consisting of oxides, oxynitrides and nitrides; each of the first phosphor and the second phosphor has a luminous efficiency of 35% or higher when excited by the visible light from the semiconductor light emitting device at room temperature; the second phosphor is capable of absorbing emitted light from the first phosphor; the first phosphor is present in the mixture of phosphors in an amount of at least 85 weight %; the second phosphor has the following formula (3);
MaAbDcEdXe
(3)wherein; M is Eu and optionally at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; A is selected from the group consisting of bivalent metal elements other than M; D is at least one element selected from the group consisting of tetravalent metal elements; E is at least one element selected from the group consisting of trivalent metal elements; X is at least one element selected from the group consisting of O, N, and F; and a, b, c, d, and e satisfy the following conditions;
a+b=1;
0.00001≦
a≦
0.1;
0.5≦
c≦
1.8;
0. 5≦
d≦
1.8;
0.8×
(2/3+4/3×
c+d)≦
e; and
e≦
1.2×
(2/3+4/3×
c+d).- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
A comprises Ca; D comprises Si; E comprises Al; and X comprises N.
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10. A light emitting device as defined in claim 1, wherein
M is Eu; -
A is Ca; D is Si; E is Al; and X is N or a mixture of N and O.
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11. A phosphor mixture, comprising:
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CaAlSiN3;
Eu; andCa3Sc2Si3O12;
Ce;wherein; the mixture comprises Ca3Sc2Si3O12;
Ce in an amount of 94 wt % based on a total weight of the phosphor mixture; andthe mixture comprises CaAlSiN3;
Eu in an amount of 6 wt % based on a total weight of the phosphor mixture. - View Dependent Claims (12)
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13. A phosphor mixture, comprising:
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a first phosphor having a composition given by the formula MaAbDcEdXe, wherein; M comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb; A comprises at least one element selected from the group consisting of divalent metal elements other than M; D comprises at least one element selected from the group consisting of tetravalent metal elements; E comprises at least one element selected from the group consisting of trivalent metal elements; and X comprises at least one of O and N; wherein;
a+b=1;
c=d=1;
0.8×
(2/3+4/3×
c+d) ≦
e; and
e≦
1.2×
(2/3+4/3×
c+d); anda second phosphor having an emission peak at a wavelength of from 490 nm to 550 nm when irradiated with excitation light having a wavelength of from 420 to 500 nm. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification