Light emitting packages and methods of making same

• US 20080054280A1
• Filed: 09/06/2006
• Published: 03/06/2008
• Est. Priority Date: 09/06/2006
• Status: Active Grant

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: Gelcore (General Electric Company)
• Inventors: Radkov, Emil, Reginelli, James, Aanegola, Srinath K.
• Granted Patent: US 7,842,960 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: G02F 1/353 Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body
• CPC Class Codes: H01S 5/0087 for illuminating phosphorescent or fluorescent materials, e.g. using optical arrangements specifically adapted for guiding or shaping laser beams illuminating these materials
• CPC Class Codes: H01S 5/02253 using lenses
• CPC Class Codes: H01S 5/02257 using windows, e.g. specially adapted for back-reflecting light to a detector inside the housing

Abstract

In a light emitting package (8), at least one light emitting chip (12, 14, 16, 18) is supported by a board (10). A light transmissive encapsulant (30) is disposed over the at least one light emitting chip and over a footprint area (32) of the board. A light transmissive generally conformal shell (40) is disposed over the encapsulant and has an inner surface (44) spaced apart by an air gap (G) from, and generally conformal with, an outer surface (34) of the encapsulant. At least one phosphor (50) is disposed on or embedded in the conformal shell to output converted light responsive to irradiation by the at least one light emitting chip. A thermally conductive filler material disposed in the generally conformal shell (40) is effective to enhance a thermal conductivity of the composite shell material to a value higher than 0.3 W/(m.K).

Claims

1. A lighting package comprising:

at least one light emitting chip;

a board supporting the at least one light emitting chip;

a light-transmissive encapsulant disposed over the at least one light emitting chip and over a footprint area of the board;

a light-transmissive generally conformal shell disposed over the light-transmissive encapsulant and having an inner surface spaced apart by an air gap from and generally conformal with an outer surface of the light-transmissive encapsulant; and

at least one phosphor disposed on or embedded in the conformal shell and configured to output converted light responsive to irradiation by the at least one light emitting chip.

2. The lighting package as set forth in claim 1, wherein the light-transmissive encapsulant and conformal shell are generally dome-shaped and the footprint area of the board is generally elliptical or circular.

3. The lighting package as set forth in claim 2, wherein the light-transmissive encapsulant and conformal shell are generally hemispherical and the footprint area of the board is generally circular with a radius about equal to a radius of the hemispherical light-transmissive encapsulant.

4. The lighting package as set forth in claim 3, wherein the generally circular footprint area of the board extends at least two millimeters beyond an outermost edge of the at least one light emitting chip.

5. The lighting package as set forth in claim 4, wherein the at least one light emitting chip includes a plurality of light emitting chips arranged on the board with an inter-chip spacing of at least about one times a principal lateral dimension of a largest chip of the plurality of light emitting chips.

6. The lighting package as set forth in claim 3, wherein a gap between the outer surface of the light-transmissive encapsulant and the inner surface of the conformal shell is at least about 0.5 millimeter.

7. The lighting package as set forth in claim 1, wherein the at least one light emitting chip is configured to emit violet or ultraviolet radiation and the phosphor is configured to convert substantially all of the radiation emitted by the at least one light emitting chip into converted light in the visible wavelength range.

8. The lighting package as set forth in claim 1, wherein the at least one light emitting chip is configured to emit radiation having a spectrum that is principally below 425 nanometers in wavelength, and the phosphor is configured to convert substantially all of the radiation emitted by the at least one light emitting chip into white or substantially white light.

9. The lighting package as set forth in claim 1, wherein the conformal shell is formed of a material having a thermal conductivity that is higher than 0.3 W/(m.K).

10. The lighting package as set forth in claim 9, wherein the conformal shell is formed of a material having a thermal conductivity that is higher than 1 W/(m.K).

11. A lighting package comprising:

at least one light emitting chip;

a board supporting the at least one light emitting chip; and

a generally dome-shaped light-transmissive encapsulant disposed over the at least one light emitting chip and over a generally elliptical or circular footprint area of the board that extends at least two millimeters beyond an outermost edge of the at least one light emitting chip.

12. The lighting package as set forth in claim 11, wherein the at least one light emitting chip includes a plurality of light emitting chips arranged on the board with an inter-chip spacing of at least about one times a principal lateral dimension of a largest chip of the plurality of light emitting chips.

13. The lighting package as set forth in claim 11, wherein the light-transmissive encapsulant is generally hemispherical.

14. The lighting package as set forth in claim 11, further comprising:

a phosphor disposed remotely from the at least one light emitting chip in a dome-shaped phosphor layer region that is generally conformal with an outer surface of the generally dome-shaped light-transmissive encapsulant.

15. The lighting package as set forth in claim 14, further comprising:

a thermally conductive filler material disposed in the dome-shaped light-transmissive encapsulant, the disposed thermally conductive filler material being effective to enhance a thermal conductivity of the composite encapsulant material to a value higher than 0.3 W/(m.K).

16. The lighting package as set forth in claim 14, further comprising:

a light-transmissive generally conformal shell disposed over the generally dome-shaped light-transmissive encapsulant, the conformal shell being made of a different material from the material of the dome-shaped light-transmissive encapsulant, the generally conformal shell being generally conformal with the outer surface of the light-transmissive encapsulant.

17. The lighting package as set forth in claim 16, wherein the phosphor is disposed on or embedded in the light-transmissive generally conformal shell.

18. The lighting package as set forth in claim 17, further comprising:

a thermally conductive filler material disposed in the light-transmissive generally conformal shell, the disposed thermally conductive filler material being effective to enhance a thermal conductivity of the composite shell material to a value higher than 0.3 W/(m.K).

19. The lighting package as set forth in claim 14, wherein the at least one light emitting chip is configured to emit radiation having a spectrum that is principally below 425 nanometers in wavelength, and the phosphor is configured to convert the radiation emitted by the at least one light emitting chip into visible light.

20. The lighting package as set forth in claim 14, further comprising:

a layer of legend ink disposed over at least most of the generally elliptical or circular footprint area of the board.

21. A lighting package comprising:

one or more light emitting chips configured to collectively generate at least about the one watt of optical output power;

a board supporting the one or more light emitting chips;

a light-transmissive encapsulant disposed over the one or more light emitting chips and over a footprint area of the board; and

at least one remote phosphor disposed in a phosphor layer region located remote from the one or more light emitting chips and proximate to an outer surface of the light-transmissive encapsulant, the remote phosphor configured to output converted light responsive to irradiation by the one or more light emitting chips;

wherein a heat-sinking component in thermal communication with substantially all of the phosphor layer region comprises a material having a thermal conductivity that is higher than 0.3 W/(m.K).

22. The lighting package as set forth in claim 21, wherein the heat-sinking component includes the light-transmissive encapsulant, and the light-transmissive encapsulant comprises:

a thermally conductive filler material disposed in the light-transmissive generally conformal shell, the disposed thermally conductive filler material being effective to enhance a thermal conductivity of the composite shell material to a value higher than 1 W/(m.K).

23. The lighting package as set forth in claim 21, further comprising:

a generally conformal glass shell disposed over the light-transmissive encapsulant wherein the heat-sinking component in thermal communication with substantially all of the phosphor layer region includes the generally conformal glass shell, the generally conformal glass shell comprising glass and a thermally conductive filler material disposed in the glass to enhance a thermal conductivity of the glass to a value higher than 0.3 W/(m.K).

24. The lighting package as set forth in claim 21, wherein the heat-sinking component in thermal communication with substantially all of the phosphor layer region comprises nanometer-sized thermally conductive filler particles with particle size less than 100 nm.

25. A method for manufacturing a lighting package, the method comprising:

securing at least one light emitting chip to a board;

disposing a light-transmissive encapsulant over the at least one light emitting chip and over a footprint portion of the board;

disposing a light-transmissive generally conformal shell over the light-transmissive encapsulant, the disposed conformal shell having an inner surface spaced apart by an air gap from and generally conformal with an outer surface of the light-transmissive encapsulant; and

disposing at least one phosphor on or embedded in the conformal shell, the at least one phosphor being configured to output converted light responsive to irradiation by the at least one light emitting chip.

26. The method as set forth in claim 25, wherein the disposing of the light-transmissive generally conformal shell over the light-transmissive encapsulant is performed after the disposing of the light-transmissive encapsulant over the at least one light emitting chip and over the footprint portion of the board.

27. The method as set forth in claim 26, wherein the disposing of the light-transmissive encapsulant over the at least one light emitting chip and over the footprint portion of the board comprises:

securing a hemispherical mold over the at least one light emitting chip and over the footprint portion of the board;

injecting a flowable material into the secured hemispherical mold, the flowable material hardening in the mold to define the light-transmissive encapsulant; and

removing the hemispherical mold, the hardened light-transmissive encapsulant remaining attached to the board after the removing.