US Patent 7748874 Light pipe and illuminating device having the same

A light pipe and an illuminating device having the light pipe are provided. The light pipe includes an optical film including a plurality of prisms and being rolled to have a cavity extending along a longitudinal direction of the prisms; and a supporter surrounding the optical film having the cavity, wherein a side surface of one of the prisms has the maximum surface roughness of about 600 nm to about 1.5 □. Accordingly, it is possible to emit a light toward a distant area through the diffraction of light and thus to provide uniform luminance.