Semiconductor light emitting device wherein a linear expansion coefficient of an intermediate layer is larger than a linear expansion coefficient of a first semiconductor layer and smaller than a linear expansion coefficient of a wavelength conversion layer
View Patent ↗According to one embodiment, a semiconductor light emitting device includes first and second columnar units, a wavelength conversion layer, a light emitting unit, a resin unit and an intermediate layer. The first columnar unit extends in a first direction. The second columnar unit is provided apart from the first columnar unit, and extends in the first direction. The wavelength conversion layer is provided apart from the first and second columnar units in the first direction. The light emitting unit includes first and second semiconductor layers, and a light emitting layer configured to emit a first light. The resin unit covers side surfaces along the first direction of the first and second columnar units and the light emitting unit, and a surface of the light emitting unit. The intermediate layer includes first and second portions, and has a thickness thinner than a peak wavelength of the first light.
1. A semiconductor light emitting device comprising:
a conductive first columnar unit extending in a first direction;
a conductive second columnar unit provided apart from the first columnar unit in a second direction crossing the first direction and extending in the first direction;
a wavelength conversion layer provided apart from the first columnar unit and the second columnar unit in the first direction;
a light emitting unit including:
a first semiconductor layer of a first conductivity type including:
a first semiconductor portion provided between at least part of the first columnar unit and the wavelength conversion layer; and
a second semiconductor portion provided between the second columnar unit and the wavelength conversion layer;
a second semiconductor layer of a second conductivity type provided between the second columnar unit and the second semiconductor portion; and
a light emitting layer provided between the second semiconductor portion and the second semiconductor layer and configured to emit a first light;
a resin unit covering a side surface along the first direction of the first columnar unit, a side surface along the first direction of the second columnar unit, a side surface of the light emitting unit, and a surface on a side of the first columnar unit and the second columnar unit of the light emitting device; and
an intermediate layer including:
a first portion in contact with the first semiconductor layer and the wavelength conversion layer; and
a second portion in contact with the resin unit and the wavelength conversion layer,
having a thickness thinner than a peak wavelength of the first light, and including a material different from a material included in the wavelength conversion layer,
wherein a linear expansion coefficient of the intermediate layer is larger than a linear expansion coefficient of the first semiconductor layer and smaller than a linear expansion coefficient of the wavelength conversion layer.
2. The device according to claim 1 , wherein a thickness of the intermediate layer is less than 440 nanometers.
3. The device according to claim 1 , wherein
the intermediate layer includes a plurality of fillers,
at least one of the fillers has a central portion and an outer shell around the central portion, and
a density of the central portion is lower than a density of the outer shell.
4. The device according to claim 3 , wherein a diameter of each of the fillers is not more than a thickness of the intermediate layer.
5. The device according to claim 1 , further comprising an insulating layer provided between the light emitting unit and the resin unit,
the intermediate layer further including a third portion in contact with part of the insulating layer and the wavelength conversion layer.
6. The device according to claim 1 , wherein a thickness of the wavelength conversion layer is not less than 80 micrometers and not more than 250 micrometers.
7. The device according to claim 1 , wherein
the wavelength conversion layer includes at least one of a silicone-based resin, an acrylic-based resin, and an epoxy-based resin and
the intermediate layer includes at least one of silicon oxide and silicon nitride.
8. The device according to claim 1 , wherein a thickness of the intermediate layer is not less than 20 micrometers and not more than 150 micrometers.
9. The device according to claim 1 , wherein the intermediate layer includes at least one of SiO 2 , TiO 2 , ZrO 2 , ZnO, KTaO 3 , Al 2 O 3 , MgO, Y 2 O 3 , CuSrO 2 , AlN, SiC, CaC 2 , BaF 2 , and CaF 2 .
10. The device according to claim 1 , wherein the intermediate layer includes a silane coupling agent.
11. The device according to claim 1 , wherein
the intermediate layer includes a silicon atom and a functional group bonded to the silicon atom and
the functional group includes at least one of an epoxy group, an amino group, a methacrylic group, a vinyl group, and a mercapto group.
12. The device according to claim 1 , wherein
the intermediate layer includes a coupling film and a plurality of fillers dispersed in the coupling film, and
the coupling film includes a silicon atom and a functional group bonded to the silicon atom and the functional group includes at least one of an epoxy group, an amino group, a methacrylic group, a vinyl group, and a mercapto group.
13. The device according to claim 1 , wherein
the intermediate layer includes a plurality of fillers and
the fillers include at least one of SiO2 and ZrO2.
14. The device according to claim 1 , wherein
the intermediate layer includes a plurality of fillers and
the fillers include at least one of antimony-doped tin oxide, tin-oxide-doped indium oxide, antimony pentoxide, phosphorus-doped tin oxide, and aluminum-doped zinc oxide.
15. The device according to claim 1 , wherein
the intermediate layer includes a plurality of fillers and
a diameter of each of the fillers is 5 nanometers or more.
16. The device according to claim 1 , wherein
the intermediate layer includes a plurality of fillers and
the fillers include at least one metal of Pt, Ag, Si, Ti, Zr, Zn, Ta, Al, Ni, and Cu and at least one of the compounds including at least one of Pt, Ag, Si, Ti, Zr, Zn, Ta, Al, Ni, and Cu.
17. The device according to claim 1 , wherein
the resin unit includes an epoxy resin,
the wavelength conversion layer includes a light transmissive resin including a silicone resin and a plurality of particles 62 dispersed in the light transmissive resin, and
the intermediate layer includes a silicon atom and an epoxy group bonded to the silicon atom.
18. The device according to claim 1 , wherein
the intermediate layer includes a filler of hollow silica.
19. The device according to claim 18 , wherein a refractive index of the intermediate layer is between a refractive index of the first semiconductor layer and a refractive index of the wavelength conversion layer.