Fig. 1: Working scheme for active beam-shaping OLEDs.
From: Real-time beam shaping without additional optical elements
a Two stacked OLED units, electrically connected for AC operation; b Experimental setup for analysis of the brightness distribution on a planar, two-dimensional surface. The OLED and the screen have to be placed parallel to each other. The evaluation of the brightness is done in the vertical direction, as indicated by the dotted line; c Using PWM, different AC signals can be applied to the device, resulting in either a ring-shaped beam (left), broad homogeneous illumination (centre) or a focused spot (right); d Respective irradiance as a function of the viewing angle for the conditions shown in c, measured using a spectro-goniometer
