A backlight unit comprising: a plurality of light sources disposed on a printed circuit; light source protective elements located on the plurality of light sources; a reflective plate located on the printed circuit and including a plurality of holes, each of the holes located to correspond to a respective one of the plurality of light sources, wherein each of the light source protective elements is disposed inside a respective one of the holes included in the reflective plate, wherein each light source and the reflective plate are configured such that light emitted by the light source and travelling in a sideways direction from the light source is reflected from the side surface of the respective hole of the reflective plate, to then travel toward a front surface of the backlight unit, and the light source protective elements are separated from each other; a coating layer disposed on the light source protective elements and the reflective plate and having a bonding function; a base film located on the coating layer and bonded by the coating layer, wherein the coating layer and the base film have a light guide function; a plurality of first light conversion patterns that are disposed on at least one of both surfaces of the base film and located in respective areas corresponding to the plurality of light sources, and are configured to change traveling paths of at least some of incident light; and a plurality of second light conversion patterns that are disposed on at least one of both surfaces of the first light conversion patterns and configured to convert wavelengths of at least some of incident light, wherein a bottom surface of the coating layer contacts both top surfaces of the light source protective elements and a top surface of the reflective plate. a plurality of light sources disposed on a printed circuit; light source protective elements located on the plurality of light sources; a reflective plate located on the printed circuit and including a plurality of holes, each of the holes located to correspond to a respective one of the plurality of light sources, wherein each of the light source protective elements is disposed inside a respective one of the holes included in the reflective plate, wherein each light source and the reflective plate are configured such that light emitted by the light source and travelling in a sideways direction from the light source is reflected from the side surface of the respective hole of the reflective plate, to then travel toward a front surface of the backlight unit, and the light source protective elements are separated from each other; a coating layer disposed on the light source protective elements and the reflective plate and having a bonding function; a base film located on the coating layer and bonded by the coating layer, wherein the coating layer and the base film have a light guide function; a plurality of first light conversion patterns that are disposed on at least one of both surfaces of the base film and located in respective areas corresponding to the plurality of light sources, and are configured to change traveling paths of at least some of incident light; and a plurality of second light conversion patterns that are disposed on at least one of both surfaces of the first light conversion patterns and configured to convert wavelengths of at least some of incident light, wherein a bottom surface of the coating layer contacts both top surfaces of the light source protective elements and a top surface of the reflective plate.