A backlight unit and a display device including the backlight unit are discussed. According to an embodiment, the invention provides a light generating device comprising: a first layer; a plurality of light source devices disposed on the first layer and configured to emit light, at least one of the light source devices including a light emitting diode for generating the light; a reflection layer disposed on the first layer and configured to reflect the light emitted from the light source devices; a second layer covering the light source devices and the reflection layer and configured to propagate the light reflected by the reflection layer, the second layer including a plurality of depressed portions, at least one of the depressed portions disposed between two adjacent light source devices among the plurality of light source devices; and at least one third layer disposed on the second layer and configured to diffuse the light propagated by the second layer.