The present invention relates to a light generating device comprising a slab light guide (1), at least one light input unit (2) arranged on at least one side (10) of said light guide (1) comprising at least one light source (20) and a light incoupling means (21) for coupling light into said light guide (1), and at least one light output unit (3) arranged on at least one side (11) of said light guide (1). In order to provide a device that provides polarized light of a high homogeneity the light output unit (3) according to the present invention comprises a polarized light emitting waveguide plate (31) for selectively coupling light of a first polarization state out of said light guide (1).The present invention further relates to a display device, in particular an LCD, comprising a light generating device according to the invention.