DIFFUSION LENS AND DISPLAY DEVICE HAVING SAME

A diffusion lens includes a first lens surface having a concave curved shape such that light generated from a light source is incident on the first lens surface, a second lens surface having a convex curved shape such that part of the light incident on the first lens surface is output from the second lens surface, a side surface extending from a periphery of the second lens surface in a vertical direction of the diffusion lens such that part of the rest of the light incident on the first lens surface is output from the side surface, and a bottom surface extending from a periphery of the first lens surface in a horizontal direction of the diffusion lens to meet a periphery of the side surface. Rates of change of the first lens surface and the second lens surface have the same sign, and a pattern in which arbitrary shapes are irregularly disposed or a pattern in which specified shapes are regularly or irregularly disposed is formed on the side surface and the bottom surface to diffuse the light passing through the side surface and diffuse the light reflected by the bottom surface. Besides, it may be permissible to prepare various other embodiments speculated through the specification.