Patent ID: 7766500

Claim:
A backlight unit comprising: a backlight chassis arranged to house a lamp such that a diffusion plate and optical sheets are arranged adjacent to the lamp, where a thickness of the optical sheets is less than a thickness of the diffusion plate, the backlight chassis including a support surface arranged to support the diffusion plate, and the optical sheets; and a frame arranged to hold the diffusion plate and the optical sheets with the support surface of the backlight chassis, the diffusion plate and the optical sheets being interposed between the frame and the support surface; wherein the diffusion plate includes, on an edge of the diffusion plate, concave portions including a notch; the backlight chassis includes, on the support surface, protrusion portions arranged to fit into the concave portions of the diffusion plate to thereby position the diffusion plate; a height of the protrusion portions is substantially equal to or less than the thickness of the diffusion plate; and at least a portion of each of the protrusion portions is located under the optical sheets.