A backlight unit A backlight unit comprises first and second glass substrates, a resin layer between the first and second glass substrates, light sources on the first and second glass substrates, first and second transistors on the first and second glass substrates and electrically connected with the light sources, and spaced apart from each other, first conductive layers on a portion of an upper surface of the first glass substrate, second conductive layers on a portion of an upper surface of the second glass substrate, and third conductive layers on the first glass substrate, the second glass substrate, and the resin layer, wherein one of the third conductive layers is electrically connected with one of the first conductive layers and one of the second conductive layers and is on a portion of an upper surface of the resin layer.