Open AccessIllumination uniformity of an edge-lit backlight with emission angle control
Author(s) -
Kenichi Imai,
Ichiro Fujieda
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.011969
Subject(s) - backlight , optics , liquid crystal display , ray tracing (physics) , materials science , enhanced data rates for gsm evolution , viewing angle , light guide , ray , total internal reflection , stray light , light emitting diode , optoelectronics , light source , physics , computer science , computer vision
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.