An illumination device comprising a plurality of light sources emitting, an optical gate; a light collector, an optical gate, and an optical projecting system adapted to image the optical gate at a distance along the optical axis. The light collector is adapted to collect light from a plurality of light sources and where the light collector comprises a plurality of lenslets collecting light from the light sources and convert the light into a plurality of light beams propagating along an optical axis. The lenslets are arranged in a dense pattern. A plurality of outermost adjacent lenslets is located along an outer circular boundary having the same radial distance to a center of the light collector. The dense pattern has been obtained by optimizing a packaging density defined by a ratio of a sum of areas of circular cross sections of the lenslets and an area of the outer circular boundary.