PLANAR LIGHTING DEVICE

摘要

The present invention relates to a lighting device comprising a light-guide arrangement in which inputted light from at least one light source is propagated through and at least partly confined within the light-guide arrangement by means of total internal reflection. The light-guide arrangement comprises first (6) and second (7) light-guide plates and an intermediate layer (8) having a refractive index which is lower than the refractive index of said first light-guide plate (6) , said first light-guide plate (6) being arranged to receive light from said at least one light source. The second (7) light-guide plate comprises an out-coupling structure (10) to output and collimate light from the lighting device. This light-guide arrangement provides an improved lateral light-intensity averaging effect, such that light is more uniformly emitted from the output surface of the lighting device, even if said at least one light source is point or line-shaped.