Frame based package for flip-chip LED
View Patent ↗A hollow frame is configured to surround the periphery of a substantially self-supporting flip-chip light emitting device. The frame may be shaped to also contain a wavelength conversion element above the light emitting surface of the light emitting device. The lower surface of the light emitting device, which is exposed through the hollow frame, includes contact pads coupled to the light emitting element for surface mounting the light emitting module on a printed circuit board or other fixture. The flip-chip light emitting device may include a patterned sapphire substrate (PSS) upon which the light emitting element is grown, the patterned surface providing enhanced light extraction from the light emitting element, through the patterned sapphire substrate.
1. A light emitting device, comprising:
a frame defining a through hole;
a light emitting chip secured within the through hole, the light emitting chip comprising one or more sides in direct contact with one or more walls of the through hole, wherein the light emitting chip comprises:
a substrate;
a light emitting element on the substrate, wherein the light emitting element comprises an active region that is sandwiched between an n-type semiconductor and a p-type semiconductor; and
contact pads on a surface of the light emitting element that is opposite the substrate, wherein at least a first contact pad is connected to the n-type semiconductor and a second contact pad is connected to the p-type semiconductor; and
a cap secured within the through hole.
2. The device of claim 1 , wherein the substrate is a growth substrate upon which the light emitting element is formed.
3. The device of claim 1 , wherein the substrate comprises a patterned sapphire substrate.
4. The device of claim 1 , wherein the cap receives the light from the substrate, and emits light from a light emitting surface of the cap.
5. The device of claim 4 , wherein the cap includes a wavelength conversion material that absorbs some or all of the light from the light emitting element and converts it to light of a different wavelength.
6. The device of claim 4 , wherein the frame includes reflective inner walls adjacent the substrate and the cap.
7. The device of claim 1 , wherein the frame surrounds a plurality of light emitting elements.
8. The device of claim 1 , wherein the through hole is sized to provide a friction fit to the light emitting chip or the frame comprises a heat shrink material shrunken to secure the light emitting chip.
9. The device of claim 8 , wherein:
the cap is a pre-formed element; and
the through hole includes a step feature that introduces a restriction in the through hole that controls a location of the cap or the light emitting chip within the through hole.
10. The device of claim 1 , further comprising an intermediate optical element between the light emitting chip and the cap.
11. A frame structure, comprising:
a frame including a plurality of through holes;
a plurality of light emitting chips situated in the through holes, each of the light emitting chips comprising one or more sides in direct contact with one or more walls of a corresponding through hole, each of the light emitting chips including:
a substrate;
a light emitting element being situated on the substrate and emitting light through the substrate; and
contact pads that are formed on a surface of the light emitting element that is opposite the substrate; and
a plurality of caps secured within the through holes;
wherein each of the through holes allows external contact directly to the contact pads and allows light from the substrate to exit the frame structure.
12. The frame structure of claim 11 , wherein each cap is optically coupled to the substrate of the light emitting chip within a corresponding through hole.
13. The frame structure of claim 12 , wherein each cap includes a wavelength conversion material.
14. The frame structure of claim 11 , wherein each through hole is sized to provide a friction fit to a corresponding light emitting chip or the frame comprises a heat shrink material shrunken to secure the light emitting chips.
15. The frame structure of claim 14 , wherein:
each cap is a pre-formed element; and
each through hole includes a step feature that introduces a restriction in the through hole that controls a location of a corresponding cap or light emitting chip within the through hole.
16. A method of forming light emitting modules, comprising:
providing a frame structure that includes a plurality of through holes;
placing a light emitting chip within each of the through holes, each of the light emitting chips comprising one or more sides in direct contact with one or more walls of a corresponding through hole, wherein each of the light emitting chips includes:
a substrate;
a light emitting element situated on the substrate and emitting light through the substrate; and
contact pads that are formed on a surface of the light emitting element that is opposite the substrate;
placing a cap within each of the through holes; and
slicing the frame structure to provide individual light emitting modules each including one or more light emitting chips, wherein each through hole allows external contact directly to the contact pads and allows light from the substrate to exit a corresponding light emitting module.
17. The method of claim 16 , wherein the substrate is a growth substrate upon which each of the light emitting elements is formed.
18. The method of claim 16 , wherein each cap includes a wavelength conversion material.
19. The method of claim 16 , wherein said providing the frame structure comprises sizing each through hole to provide a friction fit to a corresponding light emitting chip.
20. The method of claim 16 , further comprising shrinking the frame to secure the light emitting chips within the through holes.