Abstract: A backlight assembly includes a plurality of lamps, a multi-plate diffusion member, optical sheets and a receiving container. The lamps have a rod shape extended in a first direction, and are arranged along a second direction that is substantially perpendicular to the first direction. The diffusion member is disposed above the lamps and has at least two optical plates. Each of the optical plates includes a plurality of optical patterns on a surface facing away from the lamps. The optical patterns are extended in the first direction and aligned along the second direction. The optical sheets are disposed above the diffusion member to improve optical characteristics of passed through light. The receiving container includes a reflective bottom plate and a sidewall formed on an edge of the bottom plate to receive the lamps, the diffusion member and the optical sheets.