Printed electronics, e.g. organic photo-voltaic, are usually produced by roll-to-roll printing. For this fast growing market no inline-measurement method for 2D-thickness-distributions after printing exists. In many cases layer-thicknesses are in the sub-μm-range, e.g. 10–300 nm, and ellipsometry is one typical technology for this range, but up to now only in the laboratory, since most ellipsometers are too slow and/or measure only a spot. A new concept, a stroboscopic imaging ellipsometer, enables fast measurement on a line, to acquire the 2D-distribution of thickness, right after printing.