Predicting the viewing direction performance of e-paper displays with front light under ambient lighting conditions

The inherent advantages of reflective e-paper displays (EPD) – wide viewing direction range and excellent readability even under bright sunlight – can be extended into low-light conditions by the addition of an integrated lighting unit (ILU) such as a front light. A methodology for predicting the viewing direction dependence of ambient contrast and color from display measurements and illumination models is here applied to reflective EPD where the ILU is switched on. The predictions can be used to optimize task lighting. The ILU improves the indoor performance of EPD without compromising their superior daylight performance.