Patent ID: 7871172

Claim:
A light diffusion plate, comprising: a first surface defining a plurality of first elongated arc-shaped grooves and a plurality of second elongated arc-shaped grooves therein, each first elongated arc-shaped groove and each second elongated arc-shaped groove alternately positioned in the first surface, a width of each first elongated arc-shaped groove gradually decreasing and a width of each second elongated arc-shaped groove gradually increasing along the direction from a first side surface to an opposite second side surface of the light diffusion plate; and a second surface opposite the first surface comprising a plurality of first elongated arc-shaped protrusions and a plurality of second elongated arc-shaped protrusions formed thereon, each first elongated arc-shaped protrusion and each second elongated arc-shaped protrusion are alternately positioned on the second surface, a width of the first elongated arc-shaped protrusions gradually decreasing and a width of the second elongated arc-shaped protrusions gradually increasing along the direction from a third side surface of the light diffusion plate to an opposite fourth side surface, wherein the third and fourth side surfaces intersect with the first and second side surfaces.