A backlight, comprising a backplane, a reflective sheet and a plurality of light-emitting elements, wherein an accommodating space is defined on an inner surface of the backplane, the reflective sheet is located on the inner surface of the backplane, wherein the backlight further comprises at least one light-modifying region, the light-modifying region is on the reflective sheet, the light-modifying region comprises at least one light-converting device, the light-converting device being capable of carrying out optical process on light emitted from the light-emitting elements, wherein each of the light-converting devices comprises a quantum dot material; the backplane comprises a bottom plate and first sidewalls, which are longitudinal sidewalls, and second sidewalls, which are lateral sidewalls, provided around edges of the bottom plate, and the light-modifying region being provided on the reflective sheet located on the first and second sidewalls (211, 212) and the bottom plate, and the plurality of light-emitting elements are arranged in a plurality of rows and a plurality of columns on the bottom plate in the accommodating space, characterized in that the light-modifying region comprises a plurality of first light-modifying regions (121, 122) located on the second sidewalls and the first sidewalls, wherein the first light-modifying regions located on the second sidewalls are arranged in the row direction of the light-emitting elements and correspond to the columns of the light-emitting elements, and the first light-modifying regions located on the first sidewalls are arranged in the column direction of the light-emitting elements and correspond to the rows of the light-emitting elements, wherein the row direction of the light-emitting elements is parallel to the second sidewalls, and the column direction of the light-emitting elements is parallel to the first sidewalls. each of the light-converting devices comprises a quantum dot material; the backplane comprises a bottom plate and first sidewalls, which are longitudinal sidewalls, and second sidewalls, which are lateral sidewalls, provided around edges of the bottom plate, and the light-modifying region being provided on the reflective sheet located on the first and second sidewalls (211, 212) and the bottom plate, and the plurality of light-emitting elements are arranged in a plurality of rows and a plurality of columns on the bottom plate in the accommodating space, characterized in that the light-modifying region comprises a plurality of first light-modifying regions (121, 122) located on the second sidewalls and the first sidewalls, wherein the first light-modifying regions located on the second sidewalls are arranged in the row direction of the light-emitting elements and correspond to the columns of the light-emitting elements, and the first light-modifying regions located on the first sidewalls are arranged in the column direction of the light-emitting elements and correspond to the rows of the light-emitting elements, wherein the row direction of the light-emitting elements is parallel to the second sidewalls, and the column direction of the light-emitting elements is parallel to the first sidewalls.