Sub-assembly and methods for forming the same
A sub-assembly matable to a waveguide having a recess therein includes a structure comprising a discrete light source disposed on a carrier, and a substrate and a heat spreader disposed beneath the structure. The structure has a contour complementary to the recess, such that, when the sub-assembly is joined to the waveguide, the discrete light source is within the waveguide.
1. A sub-assembly matable to a waveguide having a recess therein, the sub-assembly comprising:
a substrate;
a carrier having a substantially planar top surface raised above a top surface of the substrate, the carrier and the substrate being (i) different materials and (ii) discrete from each other;
a bare-die light-emitting diode disposed on and in direct contact with the substantially planar top surface of the carrier such that, when the sub-assembly is joined to the waveguide, the discrete light source is within the waveguide
an optically transparent encapsulation material entirely filling the recess to encapsulate the bare-die light-emitting diode and contacting at least one of the substrate or the carrier such that light from the bare-die light-emitting diode is efficiently coupled into the waveguide; and
a gap laterally between the carrier and the substrate, wherein a reflective material is disposed in the gap for reflecting light from the bare-die light-emitting diode into the waveguide.
2. The sub-assembly of claim 1 , wherein a lateral dimension of a top surface of the carrier is at least three times a lateral dimension of the bare-die light-emitting diode.
3. The sub-assembly of claim 2 , wherein the top surface of the carrier has an area at least three times an area of a top surface of the bare-die light-emitting diode.
4. The sub-assembly of claim 1 , wherein the substantially planar top surface of the carrier is reflective.
5. The sub-assembly of claim 4 , wherein the reflective top surface of the carrier is disposed within the recess.
6. The sub-assembly of claim 1 , further comprising a reflector disposed over the substrate.
7. The sub-assembly of claim 6 , wherein the reflector is in direct contact with the substrate and the waveguide.
8. The sub-assembly of claim 6 , wherein a portion of the reflector is disposed within the recess.
9. The sub-assembly of claim 8 , wherein the reflector is in direct contact with the substrate and the optically transparent encapsulation material.
10. The sub-assembly of claim 1 , wherein the bare-die light-emitting diode is electrically connected to the carrier.
11. The sub-assembly of claim 10 , wherein the bare-die light-emitting diode is electrically connected to the carrier by at least one wire.
12. The sub-assembly of claim 11 , wherein at least a portion of at least one said wire is raised above and not in contact with the top surface of the carrier.
13. The sub-assembly of claim 1 , wherein the substrate comprises an electrical connector for connection to an external power source.
14. The sub-assembly of claim 1 , wherein the bare-die light-emitting diode occupies only a portion of the top surface of the carrier.
15. The sub-assembly of claim 1 , further comprising a heat spreader disposed beneath and in contact with at least one of the substrate or the carrier.
16. The sub-assembly of claim 1 , wherein the substrate is a printed circuit board.
17. The sub-assembly of claim 1 , wherein the carrier comprises a ceramic material.
18. The sub-assembly of claim 1 , wherein the carrier is electrically connected to the substrate by at least one wire.
19. The sub-assembly of claim 18 , wherein at least a portion of at least one said wire is raised above and not in contact with the top surface of the substrate.
20. The sub-assembly of claim 1 , wherein the optically transparent encapsulation material contacts both the substrate and the carrier.
21. The sub-assembly of claim 1 , wherein the top surface of the carrier and the top surface of the substrate are substantially parallel.
22. The sub-assembly of claim 1 , wherein the carrier is disposed upon and in direct contact with a top surface of a heat spreader comprising a thermally conductive material.
23. The sub-assembly of claim 22 , wherein the substrate is disposed upon and in direct contact with the top surface of the heat spreader.
24. A method of forming a sub-assembly matable to a waveguide having a recess therein, the method comprising:
providing a carrier having a substantially planar top surface raised above a top surface of a substrate, the carrier and the substrate being (i) different materials and (ii) discrete from each other;
providing a bare-die light-emitting diode over and in direct contact with the substantially planar top surface of the carrier such that, when the sub-assembly is mated to the waveguide, the discrete light source is within the waveguide
providing an optically transparent encapsulation material entirely filling the recess to encapsulate the bare-die light-emitting diode and contacting at least one of the substrate or the carrier such that light from the bare-die light-emitting diode is efficiently coupled into the waveguide; and
providing a gap laterally between the carrier and the substrate, wherein a reflective material is disposed in the gap for reflecting light from the bare-die light-emitting diode into the waveguide.