A lighting device (1) includes one or more diode light sources (32), which are configured to emit light into the peripheral edges of a light guide (20). The light guide (20) includes a set of diffusing elements (22) for scattering the emitted light in a plurality of directions out of the front surface of the light guide (20). The diffusing elements (22) are distributed on the light guide (20) so that the scattered light achieves a particular characteristic, e.g., improved uniformity.