A light emitting device (1) for illuminating a backlight device is provided. The device comprises an array (2) of light sources and at least one reflector (3a, 3b) arranged along an edge of the array (2) of light sources. The array is arranged with alternating first (4a, 5a) and second (4b, 5b) light sources, the first light sources (4a, 5a) emitting light of a first colour (G) and the second light sources (4b, 5b) emitting light of a second colour (P). The combined intensity of at least one light source (4a, 4b) arranged adjacent to the at least one reflector (3a, 3b) and its virtual image in the reflector is about 80-120% of the average intensity of the light sources (5a, 5b) of the same colour which are not arranged adjacent to the at least one reflector. The present invention further provides an edge lit or direct lit backlight device comprising such a light emitting device, the at least one reflector being at least one inner wall of the backlight device arranged along an edge of said array of light sources. A method of operating a light emitting device for illuminating a backlight device is also provided.