Surface mountable LED package

• US 6,274,924 B1
• Filed: 11/05/1998
• Issued: 08/14/2001
• Est. Priority Date: 11/05/1998
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.), Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Sasser, Gary D., Loh, Ban Poh, Collins, William D. III, Carey, Julian A.
• Primary Examiner(s): POTTER, ROY KARL
• Application Number:
  US09/187,547
• Time in Patent Office: 1,013 Days
• Field of Search: 257/98, 257/99, 257/431, 257/676
• US Class Current: 257/676
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/642 characterized by the shape

Abstract

An LED package includes a heat-sinking slug that is inserted into an insert-molded leadframe. The slug may include an optional reflector cup. Within this cup, the LED and a thermally conducting sub-mount may be attached. Wire bonds extend from the LEDs to metal leads. The metal leads are electrically and thermally isolated from the slug. An optical lens may be added by mounting a pre-molded thermoplastic lens and a soft encapsulant or by casting epoxy to cover the LED or by a cast epoxy lens over a soft encapsulant.

Claims

1. A light emitting die assembly comprising:

metal leads;

an insulating body attached to the metal leads, the insulating bode having a cavity;

a heat sink of a first thermally conductive material, the heat sink separate from the metal leads, connected to the insulating body and positioned relative to the cavity for being thermally coupled to a die; and

a lens, positioned relative to the cavity for transmitting light emitted from the die.

2. An assembly, as defined in claim 1, further including a submount of a second thermally conductive material, connected to the heat sink.

3. An assembly, as defined in claim 2, wherein the second thermally conductive material is selected from the group consisting of pure materials, compounds, and composites of silver, copper, diamond, silicon, aluminum, tungsten, molybdenum, and beryllium.

4. An assembly, as defined in claim 1, wherein the first thermally conductive material is selected from the group consisting of pure materials, compounds, and composites of silver, copper, diamond, silicon, aluminum, tungsten, molybdenum, and beryllium.

5. An assembly as defined in claim 1, further comprising:

a die thermally coupled to the heat sink.

6. An assembly, as defined in claim 5, further comprising an optically transparent material, encapsulating the die, having a hardness less than Shore 10A.

7. An assembly, as defined in claim 5, further comprising a submount of a second thermally conductive material connected between the die and the heat sink.

8. An assembly, as defined in claim 7, wherein the second thermally conductive material is selected from the group consisting of pure materials, compounds, and composites of silver, copper, diamond, silicon, aluminum, tungsten, molybdenum, and beryllium.

9. An assembly, as defined in claim 5, wherein the first thermally conductive material is selected from the group consisting of pure materials, compounds, and composites of silver, copper, diamond, silicon, aluminum, tungsten, molybdenum, and beryllium.

10. An assembly, as defined in claim 5, further comprising a reflector cup, positioned near the heat sink, having a reflective surface.

11. An assembly, as defined in claim 10, wherein the reflective surface is selected from the group consisting of silver, aluminum, gold, silver with a dielectric coating, gold with a dielectric coating, and aluminum with a dielectric coating.

12. An assembly, as defined in claim 10, wherein the reflective surface includes a dielectric stack.

13. An assembly, as defined in claim 10, wherein the reflective surface includes at least one totally internal reflective surface formed by refractive index step changes>

0.3.

14. An assembly, as defined in claim 1, further comprising a reflector cup, positioned near the heat sink having a reflective surface.

15. An assembly, as defined in claim 14, wherein the reflective surface is selected from the group consisting of silver, aluminum, gold, silver with a dielectric coating, gold with a dielectric coating, and aluminum with a dielectric coating.

16. An assembly, as defined in claim 14, wherein the reflective surface includes a dielectric stack.

17. An assemble, as defined in claim 14, wherein the reflective surface includes at least one totally internal reflective surface formed by refractive index step changes>

0.3.

18. An assembly, as defined in claim 17, wherein the reflector cup includes a material selected from the group consisting of silver, copper, aluminum, molybdenum, diamond, silicon, alumina, aluminum nitride, aluminum oxide, and composites of silver, copper, aluminum, molybdenum, diamond, silicon, alumina, aluminum nitride, and aluminum oxide.

19. An assembly, as defined in claim 17, wherein the reflector cup includes a thermally insulating material.

20. An assembly, as defined in claim 10, wherein the reflector cup includes a material selected from the group consisting of silver, copper, aluminum, molybdenum, diamond, silicon, alumina, aluminum nitride, aluminum oxide, and composites of silver, copper, aluminum, molybdenum, diamond, silicon, alumina, aluminum nitride, and aluminum oxide.

21. An assembly, as defined in claim 10, wherein the reflector cup includes a thermally insulating material.

22. A light emitting die assembly comprising:

metal leads;

an insulating body attached to the metal leads, the insulating body having a cavity; and

a heat sink of a first thermally conductive material, the heat sink separate from the metal leads, connected to the insulating body, and positioned relative to the cavity for being thermally coupled to a die.

23. The assembly of claim 22, further including a submount of a second thermally conductive material, connected to the heat sink.

24. The assembly of claim 22, wherein the first and second thermally conductive materials are selected from the group consisting of pure materials, compounds, and composites of silver, copper, diamond, silicon, aluminum, tungsten, molybdenum, and beryllium.

25. The assembly of claim 22, further comprising a reflector cup positioned near the heat sink, having a reflective surface.

26. The assembly of claim 25, wherein the reflective surface is selected from the group consisting of silver, aluminum, gold, silver with a dielectric coating, gold with a dielectric coating, and aluminum with a dielectric coating.

27. The assembly of claim 25, wherein the reflective surface includes a dielectric stack.

28. The assembly of claim 25, wherein the reflective surface includes at least one totally internal reflective surface formed by refractive index step changes≧

0.3.