The invention relates to an illumination device for illuminating at least one light modulator system of a liquid crystal display, the device comprising at least one waveguide substrate for guiding at least one targeted light beam that can be coupled into the waveguide substrate. The waveguide substrate is at least in optical contact with at least one holographic optical decoupling substrate comprising a plurality of decoupling regions and a decoupling region is at least designed to decouple part of the targeted light beam in the form of a plurality of sub-beams in the direction of the light modulator system. At least one diffuser module is provided, said diffuser module being designed in such a way that at least the outermost sub-beams of two neighbouring decoupling regions are at least adjacent to one another before exiting the diffuser module.