Light emitting device
View Patent ↗According to one embodiment, a light emitting device includes a semiconductor light emitting element to emit a first light, a mounting member, first and second wavelength conversion layers and a transparent layer. The first wavelength conversion layer is provided between the element and the mounting member in contact with the mounting member. The first wavelength conversion layer absorbs the first light and emits a second light having a wavelength longer than a wavelength of the first light. The semiconductor light emitting element is disposed between the second wavelength conversion layer and the first wavelength conversion layer. The second wavelength conversion layer absorbs the first light and emits a third light having a wavelength longer than the wavelength of the first light. The transparent layer is provided between the element and the second wavelength conversion layer. The transparent layer is transparent to the first, second, and third lights.
1. A light emitting device, comprising:
a semiconductor light emitting element to emit a first light;
a mounting member, the semiconductor light emitting element being placed on the mounting member;
a first wavelength conversion layer provided between the semiconductor light emitting element and the mounting member in contact with the mounting member, the first wavelength conversion layer absorbing the first light and emitting a second light having a wavelength longer than a wavelength of the first light;
a second wavelength conversion layer, the semiconductor light emitting element being disposed between at least a part of the second wavelength conversion layer and the first wavelength conversion layer, the second wavelength conversion layer absorbing the first light and emitting a third light having a wavelength longer than the wavelength of the first light; and
a first transparent layer provided between the semiconductor light emitting element and the second wavelength conversion layer, the first transparent layer being transparent to the first light, the second light, and the third light.
2. The device according to claim 1 , wherein the wavelength of the third light is not longer than the wavelength of the second light.
3. The device according to claim 1 , further comprising a second transparent layer provided between the semiconductor light emitting element and the first wavelength conversion layer in contact with the semiconductor light emitting element and the first wavelength conversion layer, the second transparent layer being transparent to the first light and the second light.
4. The device according to claim 3 , wherein
a refractive index of a portion of the semiconductor light emitting element contacting the second transparent layer is higher than a refractive index of the second transparent layer, and
a refractive index of a portion of the first wavelength conversion layer contacting the second transparent layer is not higher than the refractive index of the second transparent layer.
5. The device according to claim 1 , wherein
the first wavelength conversion layer includes a first wavelength conversion particle dispersed in a resin, the first wavelength conversion particle absorbing the first light and emitting the second light, and
a particle size of the first wavelength conversion particle is not less than 1 micrometer and not more than 50 micrometers.
6. The device according to claim 5 , wherein the first wavelength conversion particle includes at least one selected from a fluorescer fine particle and a nitride semiconductor fine particle.
7. The device according to claim 5 , wherein the resin having the first wavelength conversion particle dispersed in the resin includes a silicone-based resin.
8. The device according to claim 1 , wherein the first wavelength conversion layer bonds at least a portion of the semiconductor light emitting element to at least a portion of the mounting member.
9. The device according to claim 1 , wherein
the second wavelength conversion layer includes a second wavelength conversion particle dispersed in a resin, the second wavelength conversion particle absorbing the first light and emitting the third light, and
the second wavelength conversion particle includes at least one selected from a fluorescer fine particle and a nitride semiconductor fine particle.
10. The device according to claim 9 , wherein the resin having the second wavelength conversion particle dispersed in the resin includes a silicone-based resin.
11. The device according to claim 1 , wherein at least a portion of an end portion of the second wavelength conversion layer contacts the mounting member.
12. The device according to claim 1 , wherein the first transparent layer covers the semiconductor light emitting element, and an exterior surface of the first transparent layer has a curved configuration protruding along a direction from the mounting member toward the semiconductor light emitting element.
13. The device according to claim 1 , wherein at least a portion of an end portion of the first transparent layer contacts the mounting member.
14. The device according to claim 1 , wherein the first transparent layer includes a layer including a gas.
15. The device according to claim 1 , wherein at least one selected from the first wavelength conversion layer and the second wavelength conversion layer includes at least one selected from the group consisting of silicone resin, epoxy resin, polydimethylsiloxane derivative having an epoxy group, oxetane resin, acrylic resin, cycloolefin resin, urea resin, fluorocarbon resin, and polyimide resin.
16. The device according to claim 1 , wherein
the second wavelength conversion layer includes:
a first fluorescer layer; and
a second fluorescer layer stacked with the first fluorescer layer on a side of the semiconductor light emitting element of the first fluorescer layer,
a light emission wavelength of the first fluorescer layer being shorter than a light emission wavelength of the second fluorescer layer.
17. The device according to claim 1 , wherein the first light is blue light, the second light is yellow light, and the third light is yellow light.
18. The device according to claim 1 , wherein the first light is blue light, the second light is red light, and the third light is green light.
19. The device according to claim 1 , wherein the first light is near-ultraviolet light, the second light is red light, and the third light is blue and green light.
20. The device according to claim 1 , wherein the mounting member includes a reflective film provided on a face of the mounting member on a side of the semiconductor light emitting element.