Light emitting device
According to one embodiment of the present invention, the light emitting device includes an LED element, a side wall which surrounds the LED element, a phosphor layer which is fixed to the side wall with an adhesive layer therebetween, and is positioned above the LED element, and a metal pad as a heat dissipating member. The side wall includes an insulating base which surrounds the LED element and a metal layer which is formed on a side surface at the LED element side of the base, and is in contact with the metal pad and the adhesive layer. The adhesive layer includes a resin layer that includes a resin containing particles which have higher thermal conductivity than the resin or a layer that includes solder.
1. A light-emitting device, comprising:
a light-emitting element for emitting a bluish light;
a plate-shaped phosphor layer for converting the bluish light to a yellowish light by a predetermined ratio, the phosphor layer being placed away from the light-emitting element; and
a heat dissipating member that dissipates heat generated in the phosphor layer,
wherein the phosphor layer emits a light ranging from blue color to yellow color in accordance with the predetermined conversion ratio thereof,
wherein the phosphor layer comprises a single crystal phosphor, a ceramic phosphor or a glass including phosphor particles, and
wherein the heat generated in the phosphor layer is transmitted through a metal film formed of Ag, or a metal alloy comprising Ag, and an adhesive layer adhered to the heat dissipating member, wherein the adhesive layer has a thermal conductivity of not less than 1 W/(m·K).
2. The light-emitting device, according to claim 1 , wherein the adhesive layer is formed of a solder.
3. A light-emitting device, comprising:
a light-emitting element for emitting a bluish light;
a plate-shaped phosphor layer for converting the bluish light to a yellowish light by a predetermined ratio, the phosphor layer being placed away from the light-emitting element;
a heat dissipating member that dissipates heat generated in the phosphor layer;
a reflecting member for reflecting the bluish light from the light-emitting element in a direction of the phosphor layer, and/or the yellowish light from the phosphor layer back to the phosphor layer,
wherein the phosphor layer comprises a single crystal phosphor, a ceramic phosphor or a glass including phosphor particles, and
wherein the heat generated in the phosphor layer is transmitted through a metal film formed of Ag, or a metal alloy comprising Ag, and an adhesive layer adhered to the heat dissipating member, wherein the adhesive layer has a thermal conductivity of not less than 1 W/(m·K).
4. The light-emitting device, according to claim 3 , wherein:
the reflecting member comprises a horizontal portion for reflecting the yellowish light from the phosphor layer back to the phosphor layer.
5. The light-emitting device, according to claim 4 , wherein:
the reflecting member further comprises a slanting portion for reflecting the yellowish light from the phosphor layer back to the phosphor layer.
6. The light-emitting device, according to claim 4 , wherein:
the reflecting member further comprises a vertical portion for reflecting the yellowish light from the phosphor layer back to the phosphor layer.
7. The light-emitting device, according to claim 6 , wherein:
the horizontal portion is provided along an outer edge of the phosphor layer, and the vertical portion is provided along a side surface of the phosphor layer.
8. The light-emitting device, according to claim 6 , wherein:
the reflecting member is of a common metal sheet placed on the heat dissipating member.
9. The light-emitting device, according to claim 7 , wherein:
the phosphor layer is supported by a top opening of the reflecting member.
10. A light-emitting device, comprising:
a light-emitting element for emitting a bluish light;
a plate-shaped phosphor layer for converting the bluish light to a yellowish light by a predetermined ratio, the phosphor layer being placed away from the light-emitting element;
a first heat dissipating member configured to dissipate heat generated in the phosphor layer; and
a second heat dissipating member configured to dissipate heat generated by the light-emitting element,
wherein the heat generated in the phosphor layer is transmitted through a metal film formed of Ag, or a metal alloy comprising Ag, and an adhesive layer adhered to the first heat dissipating member, wherein the adhesive layer has a thermal conductivity of not less than 1 W/(m·K).
11. The light-emitting device according to claim 10 , wherein the adhesive layer is formed of a solder.
12. The light-emitting device according to claim 10 , wherein the phosphor layer comprises a single crystal phosphor, a ceramic phosphor, or a glass including phosphor particles.
13. The light-emitting device according to claim 11 , wherein the phosphor layer comprises a single crystal phosphor, a ceramic phosphor, or a glass including phosphor particles.
14. The light-emitting device according to claim 10 , wherein the light-emitting element is a face-down type LED comprising a substrate and a crystal layer, and wherein the crystal layer is positioned on the second heat dissipating member opposite to the phosphor layer.