Light emitting device and image displaying system
A light emitting device includes a light emitting element disposed on a substrate which emits blue light, a green phosphor that emits green light upon being excited by the blue light, a red phosphor that emits red light upon being excited by the blue light, and a transparent resin including the green phosphor and the red phosphor dispersed therein. The red phosphor is arranged to be in contact with the light emitting element and the substrate. The transparent resin includes a constitutional unit including an ionic liquid including a polymerizable functional group or a derivative of the ionic liquid.
1. A light emitting device comprising:
a light emitting element that emits blue light;
a substrate provided with the light emitting element disposed thereon;
a quantum dot phosphor that emits green light upon being excited by the blue light;
a Mn 4+ -activated fluorine complex phosphor that emits red light upon being excited by the blue light; and
a transparent resin including the light emitting element, the quantum dot phosphor, and the Mn 4+ -activated fluorine complex phosphor, the light emitting element being disposed inside the transparent resin, the quantum dot phosphor and the Mn 4+ -activated fluorine complex phosphor being dispersed in the transparent resin,
the Mn 4+ -activated fluorine complex phosphor being arranged to be in contact with the light emitting element and the substrate,
the transparent resin including a constitutional unit including an ionic liquid including a polymerizable functional group or a derivative of the ionic liquid.
2. The light emitting device according to claim 1 , wherein the polymerizable functional group is a (meth)acrylic acid ester group.
3. The light emitting device according to claim 2 , wherein the ionic liquid including a (meth)acrylic acid ester group is 2-(methacryloyloxy)-ethyltrimethylammonium bis(trifluoromethanesulfonyl)imide or 1-(3-acryloyloxy-propyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.
4. The light emitting device according to claim 1 , wherein the quantum dot phosphor is provided with an ionic surface-modifying molecule bonded to a surface thereof.
5. The light emitting device according to claim 4 , wherein the ionic surface-modifying molecule is any one selected from the group consisting of 2-(diethylamino)ethanethiol hydrochloride, hexadecyltrimethylammonium bromide, myristyltrimethylammonium bromide, and thiocholine bromide.
6. The light emitting device according to claim 1 , wherein the Mn 4+ -activated fluorine complex phosphor has a particle diameter of about 10 μm or more and about 100 μm or less.
7. The light emitting device according to claim 6 , wherein the particle diameter of the Mn 4+ -activated fluorine complex phosphor is about 30 μm or more and about 100 μm or less.
8. The light emitting device according to claim 1 , wherein the quantum dot phosphor has an emission spectrum with a peak wavelength of about 520 nm or more and about 540 nm or less.
9. The light emitting device according to claim 1 , wherein the emission spectrum of the quantum dot phosphor has a half-width of about 25 nm or more.
10. The light emitting device according to claim 1 , wherein the Mn 4+ -activated fluorine complex phosphor has an emission spectrum with a half-width of about 10 nm or less.
11. The light emitting device according to claim 1 , wherein the quantum dot phosphor is composed primarily of any one selected from CdSe, CdS, CdTe, InP, InN, AlInN, InGaN, AlGaInN, and CuInGaSe.
12. The light emitting device according to claim 1 , wherein the Mn 4+ -activated fluorine complex phosphor is represented by MI 2 (MII 1-h Mn h )F 6 , where:
MI represents at least one alkali metal element selected from Li, Na, K, Rb, and Cs;
MII represents at least one tetravalent metal element selected from Ge, Si, Sn, Ti, and Zr; and
h is about 0.001 or more and about 0.1 or less.
13. The light emitting device according to claim 12 , wherein the Mn 4+ -activated fluorine complex phosphor is represented by K 2 (Si 1-h Mn h )F 6 .
14. The light emitting device according to claim 1 , wherein the Mn 4+ -activated fluorine complex phosphor is represented by MIII(MII 1-h Mn h )F 6 , where:
MIII represents at least one alkaline-earth metal element selected from Mg, Ca, Sr, and Ba;
MII represents at least one tetravalent metal element selected from Ge, Si, Sn, Ti, and Zr; and
h is about 0.001 or more and about 0.1 or less.
15. The light emitting device according to claim 14 , wherein the Mn 4+ -activated fluorine complex phosphor is represented by Ba(Si 1-h Mn h )F 6 .
16. The light emitting device according to claim 1 , wherein the blue light has a peak wavelength of about 420 nm or more and about 480 nm or less.
17. The light emitting device according to claim 16 , wherein the peak wavelength of the blue light is about 440 nm or more and about 460 nm or less.
18. An image displaying system comprising the light emitting device according to claim 1 .
19. An image displaying system comprising the light emitting device according to claim 2 .
20. An image displaying system comprising the light emitting device according to claim 3 .