LED devices

• US 20020158578A1
• Filed: 03/14/2002
• Published: 10/31/2002
• Est. Priority Date: 03/14/2001
• Status: Active Grant

• Current Assignee: Gelcore (General Electric Company)
• Original Assignee: Gelcore (General Electric Company)
• Inventors: Eliashevich, Ivan, Weaver, Stanton E. Jr., Sommers, Mathew L.
• Granted Patent: US 6,661,167 B2
• Time in Patent Office: Days
• US Class Current: 313/512
• CPC Class Codes: H01L 2224/05571 the external layer being disposed in a recess of the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/00014 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 33/54 having a particular shape

Abstract

A light emitting diode (LED) device (A) and processes for its manufacture are provided. The LED device (A) includes a light emitting chip or die (10) and an encapsulant (22) surrounding the same. The encapsulant (22) is substantially spherical in shape, and the die (10) is preferably located at a substantial center of the encapsulant (22). An electrically conductive path extends from the chip or die (10) to a periphery of the encapsulant (22) such that the chip/die (10) can be selectively energized to produce light by applying electricity to the electrically conductive path at the periphery of the encapsulant (22). Preferably, the encapsulant (22) is chosen to have an index of refraction as close as possible to the higher of an index of refraction of the die'"'"'s semiconductor material and an index of refraction of the die'"'"'s substrate (12).

Claims

1. A light emitting diode device comprising:

a light emitting diode chip;

an encapsulant surrounding the light emitting diode chip, said encapsulant being substantially spherical in shape; and

,

an electrically conductive path extending from the light emitting diode chip to a periphery of the encapsulant such that the light emitting diode chip is selectively energized to produce light by applying electricity to the electrically conductive path at the periphery of the encapsulant.

2. The device of claim 1, wherein the light emitting diode chip is substantially centered within the encapsulant.

3. The device of claim 1, wherein a diameter of the encapsulant is at least ten times as large as a largest dimension of the light emitting diode chip.

4. The device of claim 1, wherein a diameter of the encapsulant is at least twenty times as large as a largest dimension of the light emitting diode chip.

5. The device of claim 1, further comprising a phosphor, said phosphor being at least one of coated on the periphery of the encapsulant and dispersed within the encapsulant.

6. The device of claim 1, wherein an index of refraction of the encapsulant substantially matches an index of refraction of the light emitting diode chip.

7. The device of claim 1, wherein the light emitting diode chip includes a semiconductor material formed on an at least partially transparent substrate.

8. The device of claim 7, wherein an index of refraction of the encapsulant substantially matches the higher of an index of refraction of the semiconductor material and an index of refraction of the substrate.

9. The device of claim 1, wherein the electrically conductive path includes:

electrically conductive pads arranged at the periphery of the encapsulant; and

,

electrically conductive wire bonds connected between the electrically conductive pads and electrodes on the light emitting diode chip.

10. The device of claim 1, wherein the electrically conductive path includes a lead-frame having solder bumps arranged thereon, said light emitting diode chip being flip-chip bonded to the lead-frame such that the solder bumps make electrical contact with electrodes on the light emitting diode chip.

11. The device of claim 1, wherein the electrically conductive path includes:

a lead-frame having first and second leads, said first lead having a chip-receiving area to which the light emitting diode chip is bonded such that a first electrode of the light emitting diode chip is in electrical contact with the first lead; and

,

a wire bond connecting a second electrode of the light emitting diode chip to the second lead of the lead-frame.

12. The device of claim 1, wherein the electrically conductive path includes a substantially optically transparent electrically conductive material extending from the light emitting diode chip to a periphery of the encapsulant.

14. The method of claim 13, further comprising:

arranging the light emitting diode chip substantially at a center of the encapsulant.

15. The method of claim 13, further comprising:

forming a first hemispherical portion of the encapsulant;

placing the light emitting diode chip on the first hemispherical portion of the encapsulant; and

,

forming a second hemispherical portion of the encapsulant over the light emitting diode chip.

16. The method of claim 13, further comprising:

forming a first hemispherical portion of the encapsulant;

depositing a pattern of electrically conductive material on the first hemispherical portion of the encapsulant to form at least a portion of the electrically conductive path;

placing the light emitting diode chip over the first hemispherical portion of the encapsulant; and

,

forming a second hemispherical portion of the encapsulant over the light emitting diode chip and electrically conductive material.

17. The method of claim 13, further comprising:

bonding the light emitting diode chip to a lead-frame which makes up at least a portion of the electrically conductive path;

arranging a mold having a substantially spherical cavity around the light emitting diode chip; and

,

injecting an encapsulant material into the mold to form the encapsulant.

18. The method of claim 17, wherein the mold is a two part mold with each part defining a substantially hemispherical recess such that together they define the substantially spherical cavity.

19. The method of claim 17, further comprising:

supporting the lead-frame in a clamp while bonding the light emitting diode chip thereto.

13. A method of manufacturing a light emitting diode device comprising:

providing a light emitting diode chip;

surrounding the light emitting diode chip with a substantially spherical encapsulant; and

,

providing an electrically conductive path extending from the light emitting diode chip to a periphery of the encapsulant such that the light emitting diode chip is selectively energized to produce light by applying electricity to the electrically conductive path at the periphery of the encapsulant.

20. A method of producing light comprising:

providing a light emitting diode chip;

surrounding the light emitting diode chip with a substantially spherical encapsulant;

providing an electrically conductive path extending from the light emitting diode chip to a periphery of the encapsulant; and

,

applying electricity to the electrically conductive path at the periphery of the encapsulant such that the light emitting diode chip is energized to produce light.

21. The method of claim 20, further comprising:

observing the light produced to measure how much optical power is output; and

,

determining a k factor based upon the observation.

22. The method of claim 20, further comprising:

taking goniometric measurements of the light produced; and

,

modeling at least one characteristic of the light emitting diode base upon the measurements.

23. The method of claim 22, wherein the at least one characteristic includes view angle output of the light emitting diode.