Illumination uniformity of an edge-lit backlight with emission angle control.
Viewing range of a liquid crystal display can be controlled by a liquid crystal device inserted between a light source and a light-guide of an edge-lit backlight unit. Here, we propose an output coupler with a vertical optical window through which light is extracted from a light-guide. Rays with large propagation angles and those with small angles have a comparable probability of hitting this window. As a result, a single set of these output couplers can provide uniform light extraction for both settings of a wide viewing range and a narrow one. Ray tracing simulations confirm these findings.
Imai
Keita
K
Department of Photonics, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan.
Fujieda
Ichiro
I
D003198:Computer Simulation; D017076:Computer-Aided Design; D003626:Data Display; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008029:Lighting / Q000295:instrumentation* / Q000379:methods; D050866:Liquid Crystals / Q000737:chemistry* / Q000528:radiation effects*; D008962:Models, Theoretical; D012542:Scattering, Radiation