LED-based edge lit illumination system
View Patent ↗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.
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 i Ga j Al k N, 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 (PO 4 ) 3 (Cl,F,Br,OH):Eu 2+ ,Mn 2+ ,Sb 3+ ; (Ba,Sr,Ca)MgAl 10 O 17 :Eu 2+ ,Mn 2+ ; (Ba,Sr,Ca)BPO 5 :Eu 2+ , Mn 2+ ; (Sr,Ca) 10 (PO 4 ) 6 *nB 2 O 3 :Eu 2+ ; 2SrO*0.84P 2 O 5 *0.16B 2 O 3 :Eu 2+ ; Sr 2 Si 3 O 8*2 SrCl 2 :Eu 2+ ; Ba 3 MgSi 2 O 8 :Eu 2+ ; BaAl 8 O 13 :Eu 2+ ; Sr 4 Al 14 O 25 :Eu 2+ ; BaAl 8 O 13 :Eu 2+ ; 2SrO-0.84P 2 O 5-0.16 B 2 O 3 :Eu 2+ ; (Ba,Sr,Ca) 5 (PO 4 ) 3 (Cl,F,OH):Eu 2+ ,Mn 2+ ,Sb 3+ ; (Ba,Sr,Ca)MgAl 2 O 4 :Eu 2+ ; (Y,Gd,Lu,Sc,La)BO 3 :Ce 3+ ,Tb 3+ ; (Ba,Sr,Ca) 2 SiO 4 :Eu 2+ ; (Ba,Sr,Ca) 2 (Mg,Zn)Si 2 O 7 :Eu 2+ ; (Sr,Ca,Ba)(Al,Ga,In) 2 S 4 :Eu 2+ ; (Y,Gd,Tb,La,Sm,Pr,Lu) 3 (Al,Ga) 5 O 12 :Ce 3+ ; (Ca,Sr) 8 (Mg,Zn)(SiO 4 ) 4 Cl 2 :Eu 2+ ,Mn 2+ ; Na 2 Gd 2 B 2 O 7 :Ce 3+ ,Tb 3+ ; (Ba,Sr) 2 (Ca,Mg,Za)B 2 O 6 :K,Ce,Tb; (Sr,Ca,Ba,Mg,Zn) 2 P 2 O 7 :Eu 2+ ,Mn 2+ ; (Ca,Sr,Ba,Mg) 10 (PO 4 ) 6 (F,Cl,Br,OH): Eu 2+ ,Mn 2+ ; (Gd,Y,Lu,La) 2 O 3 :Eu 3+ ,Bi 3+ ; (Gd,Y,Lu,La) 2 O 2 S:Eu 3+ ,Bi 3+ ; (Gd,Y,Lu,La)VO 4 :Eu 3+ ,Bi 3+ ; SrY 2 S 4 :Eu 2+ ; CaLa 2 S 4 :Ce 3+ ; (Ca,Sr)S:Eu 2+ ; 3.5MgO*0.5MgF 2 *GeO 2 :Mn 4+ ; (Ba,Sr,Ca)MgP 2 O 7 :Eu 2+ ,Mn 2+ ; (Y,Lu) 2 WO 6 :Eu 3+ , Mo 6+ ; (Ba,Sr,Ca) 2 Si y N z :Eu 2+ and blends thereof.