Optical film and lighting and display products including same
View Patent ↗An optical film includes a transparent substrate, an optical material comprising quantum dots disposed over a surface of the substrate, and a light diffusion film disposed over the optical material, the light diffusion film including a transparent support and a diffusion layer formed over the transparent support, the light diffusion film being positioned such that the transparent support is between the optical material and the diffusion layer, the light diffusion film having a back to front haze value of at least 80% and a total back to front light transmission value of at least 50%. Other layers can optionally be included in the optical film. A backlight unit and display including the optical film taught herein are also disclosed.
1. An optical film comprising:
a transparent substrate;
an optical material comprising quantum dots disposed over a surface of the transparent substrate; and
a light diffusion film disposed over the optical material,
the light diffusion film comprising a transparent support and a diffusion layer disposed over the transparent support,
the light diffusion film being positioned such that the transparent support is between the optical material and the diffusion layer, the light diffusion layer defines a light-emitting side of the light diffusion film defining an external light-emitting surface side of the optical film, and
the light diffusion film having a back to front haze value of at least 90% and a total back to front light transmission value of at least 50%.
2. The optical film in accordance with claim 1 , wherein
the diffusion layer has an external surface with a matte finish.
3. The optical film in accordance with claim 1 , wherein
the diffusion layer includes a distribution of light diffusing particles in a transparent resin.
4. The optical in accordance with claim 3 , wherein
the light diffusing particles have a particle size in a range from about 2 microns to about 30 microns.
5. The optical film in accordance with claim 3 wherein
the light diffusing particles are of approximately the same size.
6. The optical film in accordance with claim 3 , wherein
the light diffusing particles include light diffusing particles of at least two different sizes.
7. The optical film in accordance with claim 6 , wherein
the at least two different sizes include a first size having an average diameter in a first range from about 2 to about 10 microns and a second size having an average diameter in a second range from about 10 to about 20 microns.
8. The optical film in accordance with claim 1 , wherein
the optical material is disposed on the surface of the transparent substrate.
9. The optical film in accordance with claim 1 , wherein
the optical material is disposed as a layer over the surface of the transparent substrate.
10. The optical film in accordance with claim 1 , wherein
the optical material further comprises a host material in which the quantum dots are distributed.
11. The optical film in accordance with claim 1 , wherein
the optical material includes quantum dots selected to emit light at one or more preselected wavelengths.
12. The optical film in accordance with claim 8 , wherein
the optical material includes quantum dots selected to emit light at one or more preselected wavelengths.
13. The optical film in accordance with claim 9 , wherein
the optical material includes red light-emitting quantum dots and green light-emitting quantum dots.
14. The optical film in accordance with claim 1 , wherein
the optical material is encapsulated within the optical film.
15. The optical film in accordance with claim 1 , wherein
the optical film further includes a coupling layer between the optical material and the overlaying light diffusion film.
16. The optical film in accordance with claim 15 , wherein
the coupling layer comprises an index-matching gel.
17. The optical film in accordance with claim 15 , wherein
the coupling layer comprises an optically clear adhesive.
18. The optical film in accordance with claim 1 , wherein
a second transparent substrate is disposed between the optical material and any adjacent layer or film.
19. A backlight unit comprising:
a light guide plate;
the optical film in accordance with claim 1 disposed over a first surface of the light guide plate; and
a light source unit including one or more light sources,
wherein the optical film or a surface of the light guide plate other than the first surface are positioned to receive light emitted by the light source unit, and
wherein the one or more light sources emit light of a first wavelength, and
wherein the quantum dots included in the optical material are selected to convert light of the first wavelength to light of one or more preselected wavelengths.
20. A display system comprising a display panel and the backlight unit in accordance with claim 19 configured to provide light to the display panel.
21. A display system comprising a display panel and a color conversion region comprising the optical film in accordance with claim 1 .