Light-emitting device substrate, light-emitting device, and method for manufacturing light-emitting device substrate
A substrate includes a base made of a metal material, a thermally conductive, light-reflective ceramic insulating layer, and a buffer layer formed between the base and the ceramic insulating layer and having a smaller linear expansion coefficient than the base.
1. A light-emitting device substrate comprising:
a base comprising aluminum;
a thermally conductive, light-reflective electrically insulating layer; and
a buffer layer formed between the base and the electrically insulating layer and having a smaller linear expansion coefficient than the base, wherein
the buffer layer includes an alloy of nickel and aluminum.
2. The light-emitting device substrate according to claim 1 , wherein the buffer layer has a larger linear expansion coefficient than the electrically insulating layer.
3. The light-emitting device substrate according to claim 1 , wherein the electrically insulating layer includes an epoxy resin.
4. The light-emitting device substrate according to claim 1 , wherein the electrically insulating layer includes a resin containing alumina particles.
5. The light-emitting device substrate according to claim 1 , wherein the electrically insulating layer comprises a multilayer structure, the layers of the electrically insulating layer including a thermally conductive first ceramic layer that is in contact with the buffer layer and a light-reflective second ceramic layer that is farthest away from the buffer layer.
6. A method for manufacturing the light-emitting device substrate according to claim 5 , comprising:
forming the buffer layer on the base by thermal spraying or aerosol deposition (AD),
applying a ceramic coating composition to the buffer layer to form the thermally conductive first ceramic layer, and
applying a ceramic coating composition to the first ceramic layer to form the light-reflective second ceramic layer.
7. The light-emitting device substrate according to claim 1 , wherein the buffer layer contains 90% or more by weight Ni.
8. The light-emitting device substrate according to claim 1 , wherein the buffer layer has a thickness of 10 to 100 μm.
9. The light-emitting device substrate according to claim 1 , wherein the electrically insulating layer is made of a resin containing ceramic particles.
10. A light-emitting device comprising:
the light-emitting device substrate according to claim 1 ; and
light-emitting element disposed on the electrically insulating layer.
11. A method for manufacturing the light-emitting device substrate according to claim 1 , comprising:
forming the buffer layer on the base by thermal spraying or aerosol deposition (AD); and
applying a ceramic coating composition to the buffer layer to form the thermally conductive, light-reflective electrically insulating layer.