A backlight system comprises at least two light-emitting panels (1; 11) having a front wall (2; 12), an opposing rear wall (3; 13) and opposite edge surfaces (4, 14; 5, 15). At least one of the edge surfaces (4; 14) is light-transmitting and associated with a plurality of light sources (6, 16). Light originating from the light sources (6; 16) is diffused in the panel (1; 11). Sub-surfaces (8, 18) of the rear walls (3, 13) are provided with means for extracting light from the panel (1, 11). In operation, said sub-surfaces (8, 18) project light on areas (9, 19) of an (imaginary) plane (40) which is positioned parallel to the light-emitting panels (1, 11). Said projected areas (9, 19) in the plane (40) are substantially contiguous. Preferably, said sub-surfaces (8, 18) are remote from the light-transmitting edge surfaces (4; 14). Preferably, each of said sub-surfaces (8, 18) forms a single surface covering half the front wall (2, 12) of the light-emitting panel (1, 11). Alternatively, the sub-surfaces encompass a substantial area of the rear walls, the distribution of the means for extracting light from the panel being such that the amount of extracted light changes as a function of the distance to the light-transmitting edge surfaces. Preferably, the light source comprises a plurality of red, green, blue (and amber) LEDs, each preferably having a luminous flux of at least 5 lumen.