LED-based edge lit illumination system

• US 8,324,640 B2
• Filed: 07/02/2004
• Issued: 12/04/2012
• Est. Priority Date: 07/02/2004
• Status: Active Grant

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: GE Lighting Solutions LLC (Savant Systems, LLC)
• Inventors: Jacob, Cherian, Chen, Chen-Lun Hsing, Radkov, Emil, Srivastava, Alok Mani, Setlur, Anant Achyut, Comanzo, Holly Ann, Shiang, Joseph
• Primary Examiner(s): Nadav, Ori
• Application Number:
  US10/884,205
• Publication Number:
  US 20060001036A1
• Time in Patent Office: 3,077 Days
• Field of Search: 362/31, 362600-634, 345 61- 65, 345/70, 345/71, 257/98, 257/102, 257/103
• US Class Current: 257/98
• CPC Class Codes: G02B 6/0003 the light guides being doped with fluorescent agents
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0071 with elongated shape, e.g. tube
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

An edge lit illumination system is directed to providing backlighting utilizing a luminescent impregnated lightguide. The apparatus includes an LED radiation source providing a first radiation and a lightguide optically coupled to the LED radiation source including a luminescent material embedded or coated on an output surface of the lightguide designed to absorb the first radiation, and emit one or more radiations. The illumination system may further include additional optical components such as reflective layers, for directing radiation striking the back surfaces of the light guide back into the lightguide, as well as diffusion layers, UV reflectors, and polarizers.

Claims

1. An edge lit lighting assembly comprising

an LED light source;

an optically transmissive lightguide having an input surface, a back surface, and an output surface; and

a radiation conversion material capable of absorbing at least a portion of the radiation at a first wavelength emitted by the LED and emitting a second radiation at a second wavelength;

wherein said radiation conversion material is coated on said output surface of said lightguide.

2. An edge lit lighting assembly according to claim 1, wherein said LED light source is a near-UV or violet emitting LED.

3. An edge lit lighting assembly according to claim 2, wherein said LED emits radiation at a wavelength of from about 350 to about 450 nm.

4. An edge lit lighting assembly according to claim 1, wherein said radiation conversion material is a phosphor material.

5. An edge lit lighting assembly according to claim 4, wherein said phosphor material comprises at least two different phosphors.

6. An edge lit lighting assembly according to claim 1, wherein said radiation conversion material emits white light.

7. An edge lit lighting assembly according to claim 1, further comprising a reflective layer secured to said back surface of said lightguide.

8. An edge lit lighting assembly according to claim 1, further comprising a light diffusion plate positioned over said output surface.

9. An edge lit lighting assembly according to claim 8, wherein said radiation converting material is dispersed in or coated on said light diffusion plate.

10. An edge lit lighting assembly according to claim 1, wherein said backlight assembly is suitable for use in an LCD or an illumination panel.

11. An edge lit lighting assembly according to claim 1, wherein said LED comprises a nitride compound semiconductor represented by the formula In_iGa_jAl_kN, where 0≦

i;

0≦

j, K, and i+j+k=1.

12. An edge lit lighting assembly according to claim 1, wherein said assembly comprises a backlight for an electronic display device.

13. A lightguide for use with an LED light source in an edge lit lighting assembly, said lightguide comprising

a optically transmissive monolith having an input surface, a back surface, and an output surface;

and

a radiation conversion material capable of absorbing a first radiation at a first wavelength and emitting a second radiation at a second wavelength;

wherein said radiation conversion material is coated on said output surface of said lightguide.

14. A lightguide according to claim 13, further comprising a reflective layer attached to an outside surface of said lightguide except said input surface and said output surface.

15. A lightguide according to claim 13, wherein said radiation conversions material comprises a phosphor composition.

16. A lightguide according to claim 15, wherein said phosphor composition comprises at least two different phosphors.

17. A lightguide according to claim 13, wherein said radiation conversion material emits white light.

18. An edge lit lighting assembly comprising

an LED light source;

an optically transmissive lightguide having an input surface, a back surface, and an output surface; and

a radiation conversion material capable of absorbing at least a portion of the radiation at a first wavelength emitted by the LED and emitting a second radiation at a second wavelength;

wherein said radiation conversion material is at least one of coated on said output surface of said lightguide, and dispersed in a film on the output and/or back surface of said light guide, and

wherein said phosphor material is selected from the group consisting of;

(Ba,Sr,Ca)₅(PO₄)₃(Cl,F,Br,OH);

Eu²⁺,Mn²⁺,Sb³⁺;

(Ba,Sr,Ca)MgAl₁₀O₁₇;

Eu²⁺,Mn²⁺;

(Ba,Sr,Ca)BPO₅;

Eu²⁺, Mn²⁺;

(Sr,Ca)₁₀(PO₄)₆*nB₂O₃;

Eu²⁺;

2SrO*0.84P₂O₅*0.16B₂O₃;

Eu²⁺;

Sr₂Si₃O_8*2SrCl₂;

Eu²⁺;

Ba₃MgSi₂O₈;

Eu²⁺;

BaAl₈O₁₃;

Eu²⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺;

BaAl₈O₁₃;

Eu²⁺;

2SrO-0.84P₂O_5-0.16B₂O₃;

Eu²⁺;

(Ba,Sr,Ca)₅(PO₄)₃(Cl,F,OH);

Eu²⁺,Mn²⁺,Sb³⁺;

(Ba,Sr,Ca)MgAl₂O₄;

Eu²⁺;

(Y,Gd,Lu,Sc,La)BO₃;

Ce³⁺,Tb³⁺;

(Ba,Sr,Ca)₂SiO₄;

Eu²⁺;

(Ba,Sr,Ca)₂(Mg,Zn)Si₂O₇;

Eu²⁺;

(Sr,Ca,Ba)(Al,Ga,In)₂S₄;

Eu²⁺;

(Y,Gd,Tb,La,Sm,Pr,Lu)₃(Al,Ga)₅O₁₂;

Ce³⁺;

(Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺;

Na₂Gd₂B₂O₇;

Ce³⁺,Tb³⁺;

(Ba,Sr)₂(Ca,Mg,Za)B₂O₆;

K,Ce,Tb;

(Sr,Ca,Ba,Mg,Zn)₂P₂O₇;

Eu²⁺,Mn²⁺;

(Ca,Sr,Ba,Mg)₁₀(PO₄)₆(F,Cl,Br,OH);

Eu²⁺,Mn²⁺;

(Gd,Y,Lu,La)₂O₃;

Eu³⁺,Bi³⁺;

(Gd,Y,Lu,La)₂O₂S;

Eu³⁺,Bi³⁺;

(Gd,Y,Lu,La)VO₄;

Eu³⁺,Bi³⁺;

SrY₂S₄;

Eu²⁺;

CaLa₂S₄;

Ce³⁺;

(Ca,Sr)S;

Eu²⁺;

3.5MgO*0.5MgF₂*GeO₂;

Mn⁴⁺;

(Ba,Sr,Ca)MgP₂O₇;

Eu²⁺,Mn²⁺;

(Y,Lu)₂WO₆;

Eu³⁺, Mo⁶⁺;

(Ba,Sr,Ca)₂Si_yN_z;

Eu²⁺ and blends thereof.