Light emitting diode, light emitting device using the same, and fabrication processes therefor
View Patent ↗Disclosed is a LED which can be mounted at high density on a large area display. Having a hole for heat sink in the ceramic substrate, the LED is superior in heat sink property. In order to fabricate the light emitting device, first, a secondary ceramic sheet is stacked on the ceramic substrate, followed by forming electrodes in a predetermined pattern on the secondary ceramic sheet around the hole for heat sink. On the ceramic substrate, an upper ceramic sheet with an opening is stacked to form a stacked ceramic substrate in such a way that a part of the electrodes are exposed through the opening. After co-firing the stacked ceramic substrate, a light emitting diode chip is mounted on the secondary ceramic sheet at a position corresponding to the hole for heat sink. Then, the electrodes are electrically connected with the LED chip, and the LED chip is sealed with insulating resin. A light emitting device using the LED and a fabrication method therefor are also disclosed.
1. A method for fabricating a light emitting diode, comprising the steps of:
preparing a ceramic substrate having a hole for heat sink;
stacking a secondary ceramic sheet on said ceramic substrate;
disposing electrode patterns in a predetermined pattern on said secondary ceramic sheet around the hole;
stacking on said ceramic substrate an upper ceramic sheet with an opening to form a stacked ceramic substrate in such a way that a part of the electrodes of said secondary ceramic sheet are exposed through said opening;
co-firing said stacked ceramic substrate; mounting a LED chip on said secondary ceramic sheet at a position corresponding to the hole after disposing electrodes on the electrode patterns of said secondary ceramic sheet; and sealing said LED chip within said upper ceramic sheet with an insulating resin after electrically connecting said electrodes with said LED chip.
2. The method as claimed in claim 1 , wherein said ceramic substrate and/or the ceramic sheets are made of alumina or SiC.
3. The method as claimed in claim 1 , wherein said electrode patterns are disposed of Ag paste, and said electrodes are formed by plating Ni and Au on the electrode patterns.
4. The method as claimed in claim 1 , wherein said insulating resin is made of epoxy or an Si-based transparent resin.
5. The method as claimed in claim 1 , wherein said co-firing is conducted at 800 to 1,050° C.
6. The method as claimed in claim 1 , wherein metal paste is coated along the contact line between said secondary ceramic sheet and said ceramic substrate in the hole of heat sink.
7. The method as claimed in claim 1 , wherein the hole for heat sink is filled with metal paste.
8. The method as claimed in claim 7 , wherein the hole for heat sink is filled with metal paste and a metal plate is attached on bottom surface of said ceramic substrate.
9. The method as claimed in claim 7 , wherein the hole for heat sink is fully filled with a metal paste and said ceramic substrate is entirely coated with a metal paste on its bottom surface.
10. The method as claimed in claim 1 , wherein a metal lump or slug is inserted in the hole for heat sink.
11. The method as claimed in claim 1 , wherein said secondary ceramic sheet has a hole for heat sink which is smaller than said light emitting chip and the hole for heat sink of said ceramic substrate.
12. A method for fabricating a light emitting diode, comprising the steps of:
preparing a ceramic sheet having a hole for heat sink, said ceramic sheet formed electrode patterns in a predetermined pattern thereon to make a ceramic substrate;
stacking a secondary ceramic sheet on said ceramic substrate to cover the hole for heat sink;
stacking on said ceramic substrate an upper ceramic sheet with an opening to form a stacked ceramic substrate in such a way that a part of the electrode patterns and a part or all of said secondary ceramic sheet are exposed through said opening;
co-firing said stacked ceramic substrate;
mounting a LED chip on said secondary ceramic sheet at a position corresponding to the hole after disposing electrodes on the electrode patterns of said ceramic substrate; and
sealing said LED chip within said upper ceramic sheet with an insulating resin after electrically connecting the electrodes with said LED chip.
13. A method for fabricating a light emitting device, comprising the steps of:
preparing a ceramic substrate having a plurality of holes for heat sink;
stacking a secondary ceramic sheet on said ceramic substrate;
disposing electrodes patterns in a predetermined pattern on said secondary ceramic sheet around each of the holes;
stacking on said secondary ceramic sheet an upper ceramic sheet with an opening to form a stacked ceramic substrate in such a way that a part of the electrode patterns are exposed through the opening;
co-firing said stacked ceramic substrate;
mounting LED chips on said secondary ceramic sheet at a position corresponding to each of the holes after disposing electrodes on the electrode patterns of said secondary ceramic sheet; and
sealing said LED chips within said upper ceramic sheet with insulating resin after electrically connecting said electrodes with said LED chips.
14. The method as claimed in claim 13 , wherein said secondary ceramic sheet has holes for heat sink which are smaller than said light emitting chips and the holes for heat sink of said ceramic substrate.
15. A method for fabricating a light emitting device, comprising the steps of:
preparing a ceramic substrate having a plurality of holes for heat sink, said ceramic substrate being formed electrode patterns in a predetermined pattern thereon around each of the holes;
stacking secondary ceramic sheets on said ceramic substrate to cover each of the holes for heat sink;
stacking on said ceramic substrate an upper ceramic sheet with an opening to form a stacked ceramic substrate in such a way that a part of said electrode patterns and a part or all of said secondary ceramic sheets are exposed through said opening;
co-firing said stacked ceramic substrate; mounting LED chips on said secondary ceramic sheets at a position corresponding to each of the holes after disposing electrodes on the electrode patterns of said ceramic substrate; and
sealing said LED chips within said upper ceramic sheet with insulating resin after electrically connecting said electrodes with said LED chips.
16. The method as claimed in claim 15 , wherein each of said secondary ceramic sheets are independently positioned on said ceramic substrate as to cover each hole for heat sink.
17. The method as claimed in claim 15 , wherein said secondary ceramic sheets are independently positioned on said ceramic substrate to cover at least two holes or more for heat sink.
18. The method as claimed in claim 15 , wherein said ceramic substrate has additional openings for heat sink, aside from the holes for heat sink.
19. The method as claimed in claim 15 , wherein each of said secondary ceramic sheets have a hole for heat sink beneath said light emitting diode chip.