Quantum dot films, lighting devices, and lighting methods
Light-emitting quantum dot films, quantum dot lighting devices, and quantum dot-based backlight units are provided. Related compositions, components, and methods are also described. Improved quantum dot encapsulation and matrix materials are provided. Quantum dot films with protective barriers are described. High-efficiency, high brightness, and high-color purity quantum dot-based lighting devices are also included, as well as methods for improving efficiency and optical characteristics in quantum dot-based lighting devices.
1. A display backlighting unit (BLU), comprising:
at least one primary light source that emits primary light;
a light guide panel (LGP) optically coupled to the at least one primary light source; and
a remote phosphor film comprising a first population of quantum dots (QDs) configured to emit first secondary light having a longer wavelength than the primary light;
wherein:
an optical density of the QDs in the remote phosphor film is no more than about 0.05,
the primary light transmits uniformly through the LGP and into the remote phosphor film,
at least a portion of the primary light is absorbed by the first population of QDs and reemitted by the first population of QDs as the first secondary light, and
the remote phosphor film is sandwiched between at least two barrier layers.
2. The display BLU of claim 1 , wherein the QDs comprise an emission spectrum having less than 40 nm full width and half maximum (FWHM).
3. The display BLU of claim 1 , wherein the at least two barrier layers each comprise a polymer sublayer and an oxide sublayer, and the oxide sublayer is disposed directly adjacent the remote phosphor film.
4. The display BLU of claim 3 , wherein each barrier layer eliminates or reduces pinhole defect alignment in the barrier layer, providing an effective barrier to oxygen and moisture penetration into the remote phosphor film.
5. The display BLU of claim 1 , wherein the remote phosphor film further comprises a second population of QDs configured to absorb at least a portion of the primary light and reemit a second secondary light having a longer wavelength than the primary light, the second secondary light being different from the first secondary light.
6. The display BLU of claim 5 , wherein:
the first population of QDs is configured to emit first, red, secondary light and the second population of QDs is configured to emit second, green, secondary light; and
at least a portion of the primary light is absorbed by the two populations of QDs and reemitted by the two populations of QDs as the first and second secondary light of lower energy than the primary light.
7. The display BLU of claim 5 , wherein the remote phosphor film further comprises one or more primary light scattering features which scatter primary light toward the first and second populations of QDs.
8. The display BLU of claim 7 , wherein:
the remote phosphor film comprises a first QD phosphor material film layer comprising a first matrix material and a second QD phosphor material film layer comprising a second matrix material, and
the first and second populations of QDs are embedded in the first matrix material and the second matrix material respectively.
9. The display BLU of claim 8 , wherein at least a portion of the scattering features are disposed in the first QD phosphor material film layer or the second QD phosphor material film layer.
10. The display BLU of claim 8 , wherein the one or more primary light scattering features and the first and second populations of QDs are dispersed uniformly throughout the QD phosphor material film.
11. The display BLU of claim 7 , wherein the one or more primary light scattering features comprise scattering particles.
12. The display BLU of claim 11 , wherein:
the scattering particles comprise spherical scattering beads; or
the scattering particles comprise silica, borosilicate, or polystyrene beads.
13. The display BLU of claim 7 , wherein the scattering features are formed on a top surface or a bottom surface of the QD phosphor material film.
14. The display BLU of claim 7 , where in the at least one primary light source comprises one or more blue LEDs coupled to one or more edges or a bottom surface of the LGP, and the one or more LEDs are disposed within a same plane as the LGP.
15. The display BLU of claim 1 , wherein the QDs comprise a quantum efficiency greater than or approximately equal to 90%.
16. The display BLU of claim 15 , wherein the QDs comprise a size in a range between about 1 nm and about 15 nm.
17. A quantum dot (QD) film remote phosphor package; comprising:
a phosphor film comprising a first population of QDs, wherein an optical density of the QDs is no more than about 0.05; and
at least two barrier layers attached on a bottom surface and a top surface of the phosphor film respectively;
wherein:
the phosphor film is configured to receive a primary light transmitted uniformly from a light guide panel (LGP) and into the QD film remote phosphor package, and
the first population of QDs are configured to absorb at least a portion of the primary light and reemit a first secondary light having a longer wavelength than the primary light.
18. The QD film remote phosphor package of claim 17 , wherein the QDs comprise an emission spectrum having less than 40 nm full width and half maximum (FWHM).
19. The QD film remote phosphor package of claim 17 , wherein the at least two barrier layers each comprise a polymer sublayer and an oxide sublayer, and the oxide sublayer is disposed directly adjacent the phosphor film.
20. The QD film remote phosphor package of claim 17 , wherein:
the phosphor film further comprises a second population of QDs configured to absorb at least a portion of the primary light and reemit a second secondary light having a longer wavelength than the primary light, the second secondary light being different from the first secondary light.