Light-emitting device and backlight including light-emitting device
First Claim
1. A light-emitting device, comprising:
- a first light-emitting element having an emission peak wavelength of 430 nm or more and less than 490 nm;
a second light-emitting element having an emission peak wavelength of 490 nm or more and 570 nm or less;
a support body at which the first light-emitting element and the second light-emitting element are disposed; and
a light-transmissive member containing a red phosphor and covering the first light-emitting element and the second light-emitting element, whereina content density of the red phosphor in the light-transmissive member located in a space between the first light-emitting element and the second light-emitting element is higher in a part below an upper surface of the second light-emitting element than in a part above the upper surface thereof, andthe red phosphors located in the light-transmissive member in a space between the first light-emitting element and the second light-emitting element settle out so as to be in contact with each other,wherein the red phosphor includes a phosphor having a composition represented by the following formula (II);
(x−
a)MgO.a(Ma)O.b/2(Mb)2O3.yMgF2.c(Mc)X2.(1−
d−
e)GeO2.d(Md)O2.e(Me)2O3;
Mn4+
(II)wherein Ma is at least one element selected from Ca, Sr, Ba and Zn;
Mb is at least one element selected from Sc, La and Lu;
Mc is at least one element selected from Ca, Sr, Ba and Zn;
X is at least one element selected from F and Cl;
Md is at least one element selected from Ti, Sn and Zr; and
Me is at least one element selected from B, Al, Ga and In, furthermore, x, y, a, b, c, d and e are set to satisfy the following ranges;
2≤
x≤
4;
0<
y≤
2;
0≤
a≤
1.5;
0≤
b<
1;
0≤
c≤
2;
0≤
d≤
0.5; and
0≤
e<
1.
1 Assignment
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Accused Products
Abstract
The light-emitting device includes a first light-emitting element having an emission peak wavelength of 430 nm or more and less than 490 nm, a second light-emitting element having an emission peak wavelength of 490 nm or more and 570 nm or less, a support body at which the first light-emitting element and the second light-emitting element are disposed, and a light-transmissive member containing a red phosphor and covering the first light-emitting element and the second light-emitting element. A content density of the red phosphor in the light-transmissive member in a space between the first and second light-emitting elements is higher in a part below an upper surface of the second light-emitting element than in a part above the upper surface thereof.
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Citations
18 Claims
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1. A light-emitting device, comprising:
-
a first light-emitting element having an emission peak wavelength of 430 nm or more and less than 490 nm; a second light-emitting element having an emission peak wavelength of 490 nm or more and 570 nm or less; a support body at which the first light-emitting element and the second light-emitting element are disposed; and a light-transmissive member containing a red phosphor and covering the first light-emitting element and the second light-emitting element, wherein a content density of the red phosphor in the light-transmissive member located in a space between the first light-emitting element and the second light-emitting element is higher in a part below an upper surface of the second light-emitting element than in a part above the upper surface thereof, and the red phosphors located in the light-transmissive member in a space between the first light-emitting element and the second light-emitting element settle out so as to be in contact with each other, wherein the red phosphor includes a phosphor having a composition represented by the following formula (II);
(x−
a)MgO.a(Ma)O.b/2(Mb)2O3.yMgF2.c(Mc)X2.(1−
d−
e)GeO2.d(Md)O2.e(Me)2O3;
Mn4+
(II)wherein Ma is at least one element selected from Ca, Sr, Ba and Zn;
Mb is at least one element selected from Sc, La and Lu;
Mc is at least one element selected from Ca, Sr, Ba and Zn;
X is at least one element selected from F and Cl;
Md is at least one element selected from Ti, Sn and Zr; and
Me is at least one element selected from B, Al, Ga and In, furthermore, x, y, a, b, c, d and e are set to satisfy the following ranges;
2≤
x≤
4;
0<
y≤
2;
0≤
a≤
1.5;
0≤
b<
1;
0≤
c≤
2;
0≤
d≤
0.5; and
0≤
e<
1.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
where, in the general formula (I), A is at least one selected from the group consisting of K, Li, Na, Rb, Cs and NH4+; and
M is at least one element selected from the group consisting of Group 4 elements and Group 14 elements.
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3. The light-emitting device according to claim 1, wherein the first light-emitting element and the second light-emitting element are alternately arranged in a longitudinal direction and a lateral direction at an element mounting surface of the support body.
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4. The light-emitting device according to claim 1, wherein a ratio of a light output from the second light-emitting element to that from the first light-emitting element is in a range of 0.3 or more and 0.7 or less.
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5. The light-emitting device according to claim 1, wherein an upper surface of the second light-emitting element is positioned closer to a light extraction surface of the light-emitting device, compared to an upper surface of the first light-emitting element.
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6. The light-emitting device according to claim 1, wherein the first light-emitting element and the second light-emitting element are nitride semiconductor light-emitting elements.
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7. The light-emitting device according to claim 1, wherein one of positive and negative electrodes of the first light-emitting element is connected to one of positive and negative electrodes of the second light-emitting element via a wire.
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8. A backlight comprising:
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the light-emitting device according to claim 1; and a light guide plate having a light input portion at a side surface thereof, wherein the light extraction surface of the light-emitting device and the light input portion are disposed facing each other.
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9. The light-emitting device according to claim 1, wherein the red phosphors in the light-transmissive member located in a space between the first light-emitting element and the second light-emitting element continuously contact the support body, the lateral surface of the first light-emitting element, and the lateral surface of the second light-emitting element.
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10. The light-emitting device according to claim 1, wherein the distribution density of the red phosphor is gradually increased downward from the part above the upper surface of the second light-emitting element.
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11. The light-emitting device according to claim 10, wherein the distribution density of the red phosphor is highest in the vicinity of the support body.
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12. The light-emitting device according to claim 1, wherein the volume-average particle size of the red phosphor is in range of 1 μ
- m or more and 100 μ
m less.
- m or more and 100 μ
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13. The light-emitting device according to claim 1, wherein the reflectance of the red phosphor to the light from the second light-emitting element is 70% or more.
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14. The light-emitting device according to claim 1, wherein the red phosphor further includes a phosphor selected from the group consisting of Y2O2S:
- Eu3+, La2O2S;
Eu3+, andAEuxLn(1−
x)M2O8, wherein 0<
X≤
1;
A is at least one element selected from Li, Na, K, Pb and Cs;
Ln is at least one element selected from Y, La, Cd and Lu; and
M is W or Mo.
- Eu3+, La2O2S;
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15. The light-emitting device according to claim 1, wherein the red phosphor further includes a phosphor selected from the group consisting of K2SiF6:
- Mn4+, K2(Si, Ge)F6;
Mn4+and K2TiF6;
Mn4+.
- Mn4+, K2(Si, Ge)F6;
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16. The light-emitting device according to claim 1, wherein in the space between the first light-emitting element and the second light-emitting element, the content density of the red phosphor from the upper surface of the second light-emitting element to a lower surface of the light-transmissive member is two or more times as high as that of the red phosphor in the part from the upper surface of the second light-emitting element to an upper surface of the light-transmissive member.
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17. The light-emitting device according to claim 1, wherein the light-transmissive member contains a diffusing agent.
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18. The light-emitting device according to claim 17, wherein the diffusing agent is TiO2 or SiO2.
Specification