A backlight unit may include a turning film that receives light from a light guide layer. The turning film may have a plurality of elongated protrusions that extend across the turning film. Each protrusion may have a concave surface. The concave surface may be a curved surface that curves inward towards the interior of the turning film. Light from the light guide layer may pass through the turning film and be reflected towards a viewer by the concave surfaces of the protrusions. In a liquid crystal display, the turning film may be interposed between the light guide layer and a lower polarizer. In certain embodiments, the turning film may be the only optical layer interposed between the light guide layer and the lower polarizer. In other embodiments, the turning layer and a diffuser layer may be the only optical layers interposed between the light guide layer and the lower polarizer.