An illumination system has linear array of light emitters (R,G,B,A,W) associated with it least one linear array of outcoupling means (O1,O2,O3, . . . ) for coupling light out of the illumination system. Each linear array of outcoupling means is arranged parallel to the linear array of light emitters. For each linear array of outcoupling means, a configuration of the outcoupling means and a configuration of the light emitters fulfill the requirement: NCU×NLC=NOU×NLO, wherein NCU is the number of clusters (C1,C2,C3, . . . ) per unit (U1, . . . ), NLC is the number of light emitters in each of the clusters, NOU is the number of outcoupling means per unit, NLO is the number of light emitters per outcoupling means. A “cluster” is the smallest repetitive collection of light emitters forming the linear array of light emitters. A “unit” is the smallest number of adjacent clusters repetitive with respect to the outcoupling means and with respect to the light emitters.