IP Library Granted Patent US 8,853,729
Granted Patent B2
US 8,853,729 · App. 14/051,577 · Granted Oct 7, 2014

Engineered-phosphor LED packages and related methods

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Quick Facts
Patent No.
US 8,853,729
App. No.
14/051,577
Granted
Oct 7, 2014
Kind
B2
Abstract

In accordance with certain embodiments, regions of spatially varying wavelength-conversion particle concentration are formed over light-emitting dies.

Claims (37)

1. A light-emitting device comprising:

a bare light-emitting die having (i) a top face and a bottom face opposite the top face, at least one of the top or bottom face being configured for emission of light therefrom, and (ii) a sidewall spanning the top and bottom faces;

a binder having top and bottom surfaces, at least one of which is substantially parallel to the top face of the light-emitting die, wherein at least a portion of the binder is disposed over the top face of the light-emitting die; and

disposed within the binder, a plurality of wavelength-conversion particles for absorbing at least a portion of light emitted from the light-emitting die and emitting converted light having a different wavelength, wherein converted light and unconverted light emitted by the light-emitting die combine to form substantially white light, wherein a divergence of color temperature of the substantially white light emitted from the light-emitting device varies, over an angular range of 0° to 70°, no more than 0.01 in terms of a Δu′v′ deviation from a spatially weighted averaged chromaticity, and u′ and v′ are chromaticity coordinates on a chromaticity diagram;

wherein (i) a concentration of the wavelength-conversion particles varies in a direction substantially perpendicular to the top and bottom faces without varying radially toward or away from the light-emitting die within a plane parallel to at least one of the top or bottom faces of the light-emitting die, and (ii) the concentration of the wavelength-conversion particles decreases in a direction extending from the top face of the light-emitting die to the bottom face of the light-emitting die.

2. The light-emitting device of claim 1 , wherein a portion of the binder is substantially free of wavelength-conversion particles.

3. The light-emitting device of claim 1 , wherein the light-emitting die comprises a light-emitting diode die.

4. The light-emitting device of claim 1 , wherein the light-emitting die comprises a GaN-based semiconductor material.

5. The light-emitting device of claim 4 , wherein the semiconductor material comprises In.

6. The light-emitting device of claim 1 , wherein the light-emitting die emits blue light.

7. The light-emitting device of claim 1 , wherein the light-emitting die emits ultraviolet light.

8. The light-emitting device of claim 1 , wherein the wavelength-conversion particles comprise phosphor particles.

9. The light-emitting device of claim 8 , wherein the phosphor particles comprise garnet and a rare-earth element.

10. The light-emitting device of claim 1 , wherein the divergence of color temperature of the substantially white light emitted from the light-emitting device varies, over an angular range of 0° to 80°, no more than 0.01 in terms of the Δu′v′ deviation from a spatially weighted averaged chromaticity.

11. The light-emitting device of claim 1 , wherein the divergence of color temperature of the substantially white light emitted from the light-emitting device varies, over an angular range of 10° to 75°, no more than 0.005 in terms of the Δu′v′ deviation from a spatially weighted averaged chromaticity.

12. The light-emitting device of claim 1 , further comprising a substrate (i) having at least two conductive traces thereon and (ii) disposed proximate the bottom face of the light-emitting die.

13. The light-emitting device of claim 12 , further comprising a contact pad disposed on the light-emitting die and electrically connected to a conductive trace on the substrate.

14. The light-emitting device of claim 13 , wherein the contact pad is electrically connected to the conductive trace by at least one of (i) a wire bond, (ii) a solder joint, (iii) an anisotropic conductive adhesive, or (iv) a conductive adhesive.

15. The light-emitting device of claim 12 , wherein the substrate comprises a leadframe.

16. The light-emitting device of claim 12 , wherein the substrate comprises a rigid material selected from the group consisting of Si, SiC, AlN, AlON, sapphire, silicon oxide, SiAlON, SiCAlON, and alloys thereof.

17. The light-emitting device of claim 12 , further comprising a package in which at least a portion of the light-emitting die and at least a portion of the substrate are disposed.

18. The light-emitting device of claim 17 , wherein the package comprises at least one of a plastic material or a ceramic material.

19. The light-emitting device of claim 12 , wherein the substrate comprises a flexible material.

20. The light-emitting device of claim 12 , wherein the substrate comprises at least one of polyethylene naphthalate, polyethylene terephthalate, polycarbonate, polyethersulfone, polyester, polyimide, polyethylene, or paper.

21. The light-emitting device of claim 12 , wherein the at least two conductive traces comprise at least one of copper, aluminum, silver, gold, silver ink, or carbon.

22. The light-emitting device of claim 1 , wherein the binder and the light-emitting die collectively define a substantially rectangular solid shape.

23. The light-emitting device of claim 1 , wherein the concentration of the wavelength-conversion particles varies substantially linearly.

24. The light-emitting device of claim 1 , wherein the concentration of the wavelength-conversion particles varies substantially step-wise linearly.

25. The light-emitting device of claim 1 , wherein the binder and the light-emitting die collectively define a substantially cubic solid shape.

26. The light-emitting device of claim 1 , wherein (i) the light-emitting die comprises first and second semiconductor layers not disposed on a semiconductor substrate, (ii) the first semiconductor layer is doped with a first polarity, and (iii) the second semiconductor layer is doped with a second polarity opposite the first polarity.

27. The light-emitting device of claim 1 , wherein (i) the light-emitting die comprises first and second semiconductor layers disposed over a semiconductor substrate, (ii) the first semiconductor layer is doped with a first polarity, and (iii) the second semiconductor layer is doped with a second polarity opposite the first polarity, and (iv) the substrate has a thickness between about 1 μm and about 25 μm.

28. The light-emitting device of claim 1 , wherein the top surface of the binder has a substantially rectangular shape.

29. The light-emitting device of claim 1 , wherein a portion of the binder extends laterally beyond the sidewall of the light-emitting die.

30. The light-emitting device of claim 1 , wherein a portion of the binder extends proximate the sidewall of the light-emitting die below a plane defined by the top face of the light-emitting die.

31. The light-emitting device of claim 1 , wherein (i) the bottom surface of the binder is proximate the light-emitting die, and (ii) at least a portion of the top surface of the binder is curved.

32. The light-emitting device of claim 1 , further comprising, disposed between the top face of the light-emitting die and the binder, a second binder substantially free of wavelength-conversion particles.

33. The light-emitting device of claim 1 , wherein the binder comprises at least one of silicone or epoxy.

Assignments (6)
CHANGE OF NAME Recorded Feb 18, 2026
From: EPISTAR CORPORATION
To: ENNOSTAR CORPORATION
Reel/Frame 075171/0402 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 17, 2025
From: EPISTAR CORPORATION
To: TAU CETI VENTURES LLC
Reel/Frame 073969/0972 →
RELEASE OF SECURITY INTEREST Recorded Jul 11, 2018
From: COMERICA BANK
To: COOLEDGE LIGHTING INC.
Reel/Frame 046325/0104 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 21, 2018
From: COOLEDGE LIGHTING INC.
To: EPISTAR CORPORATION
Reel/Frame 046169/0167 →
SECURITY INTEREST Recorded Nov 30, 2015
From: COOLEDGE LIGHTING INC.
To: COMERICA BANK
Reel/Frame 037171/0512 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 11, 2013
From: TISCHLER, MICHAEL A.; ASHDOWN, IAN
To: COOLEDGE LIGHTING INC.
Reel/Frame 031387/0481 →