Power light emitting die package with reflecting lens and the method of making the same

• US 7,456,499 B2
• Filed: 06/04/2004
• Issued: 11/25/2008
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald H., Loh, Ban P.
• Primary Examiner(s): Weiss; Howard
• Assistant Examiner(s): Ingham; John C
• Application Number:
  US10/861,929
• Publication Number:
  US 20050269587A1
• Time in Patent Office: 1,635 Days
• Field of Search: 257/99, 257/710, 257/666, 257/675, 257/719, 257/E33.058
• US Class Current: 257/710
• 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 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H01L 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body

Abstract

A light emitting die package and a method of manufacturing the die package are disclosed. The die package includes a leadframe, at least one light emitting device (LED), a molded body, and a lens. The leadframe includes a plurality of leads and has a top side and a bottom side. A portion of the leadframe defines a mounting pad. The LED device is mounted on the mounting pad. The molded body is integrated with portions of the leadframe and defines an opening on the top side of the leadframe, the opening surrounding the mounting pad. The molded body further includes latches on the bottom side of the leadframe. The lens is coupled to the molded body. A composite lens is used as both reflector and imaging tool to collect and direct light emitted by LED(s) for desired spectral and luminous performance.

Claims

1. A light emitting die package comprising:

a lead frame including a plurality of leads, the leadframe having a top side and a bottom side;

at least one light emitting device mounted on a mounting pad;

a molded body integrated with portions of the leadframe, the molded body having a first top horizontal surface with a first opening formed centrally therein and extending downward through the package, the first opening having vertical walls formed by the molded body which terminate at a second horizontal surface of the molded body, wherein a second opening is formed in the second horizontal surface that extends downward from the second horizontal surface with angled walls formed by the molded body so that the second opening has a generally frustoconical shape that surrounds the mounting pad;

a lens having an upper portion terminating at a ledge and a lower portion, the lens coupled to the molded body so that the lower portion extends downward into the second opening beyond the at least one light emitting device so as to substantially surround the at least one light emitting device, and wherein the ledge rests on the second horizontal surface with the upper portion extending up through the first opening; and

wherein a lowest point of the lower portion of the lens terminates above the leadframe to form a gap between the top side of the leadframe and the lowest point of the lens lower portion.

2. The light emitting die package recited in claim 1 wherein the molded body is a molded plastic.

3. The light emitting die package recited in claim 1 wherein the molded body includes latches on the bottom side of the leadframe, the package further comprising a heat sink coupled via a dielectric adhesive film to the leadframe, with the heat sink latched to the leadframe by the latches.

4. The light emitting die package recited in claim 1, wherein the lens is a composite optical lens.

5. The light emitting die package of claim 1, wherein the lens portion has a generally semi-spherical shape and tapers at the ledge so that the upper portion fits within the first opening with the ledge atop the second horizontal surface, and the lower portion has a generally frustoconical shape to fit within the angled second opening to surround the at least one light emitting device on the mounting pad.

6. The package of claim 1, wherein a portion of the leadframe defines a mounting pad.

7. The package of claim 1 further comprising:

an encapsulate covering the at least one light emitting device, wherein the gap permits expansion and contraction of the encapsulate during temperature cycles.

8. The package of claim 7, wherein the lens floats on the encapsulate during temperature cycles.

9. A light emitting die package, comprising:

a leadframe including a plurality of leads;

a light emitting device connected to the leads;

a molded body integrated with portions of the leadframe, the molded body including a first central opening through a top horizontal surface thereof and which terminates at a second horizontal surface below the top horizontal surface, wherein a portion of the molded body extending downward from the second horizontal surface has angled sides that taper to a smaller diameter second opening surrounding the light emitting device;

a lens extending downward beyond the light emitting device so as to substantially surround the light emitting device, the lens coupled to the molded body; and

wherein a lowest point of the lower portion of the lens terminates above the leadframe to form a cap between the top side of the leadframe and the lowest point of the lens lower portion.

10. The package of claim 9, wherein the molded body is formed of plastic.

11. The package of claim 9, wherein the leadframe has atop side and a bottom side, and the molded body includes latches on the bottom side of the leadframe.

12. The package of claim 11, further comprising a heat sink coupled via a dielectric adhesive film to the leadframe, wherein the heat sink is latched to the leadframe by the latches.

13. The package of claim 9, wherein the lens has a generally semi-spherical upper portion and a frustoconical lower portion, the upper portion tapering at a ledge of the lens which fits to the second horizontal surface of the molded body so that the frustoconical lower portion extends through the angled second opening to surround the light emitting device.

14. The package of claim 9 further comprising:

an encapsulate covering the at least one light emitting device, wherein the gap permits expansion and contraction of the encapsulate during temperature cycles.

15. The package of claim 14, wherein the lens floats on the encapsulate during temperature cycles.

16. A light emitting die package comprising:

a light emitting device;

a leadframe;

a molded body integrated with portions of the leadframe, the molded body having a first horizontal top surface with an opening there through and a second horizontal surface formed within the opening below the top surface, the diameter of the opening being constant between the top and second surfaces and gradually decreasing below the second surface due to angled walls formed by the molded body;

a lens having an upper portion terminating at a ledge that rests on the second surface and having a lower portion fitting within the angled walls formed below the second surface and extending downward beyond the light emitting device so as to substantially surround the light emitting and

wherein a lowest point of the lower portion of the lens terminates above the leadframe to form a gap between the top side of the leadframe and the lowest point of the lens lower portion.

17. The package of claim 16 further comprising:

an encapsulate covering the at least one light emitting device, wherein the gap permits expansion and contraction of the encapsulate during temperature cycles.

18. The package of claim 17, wherein the lens floats on the encapsulate during temperature cycles.