A light pipe has a transparent resin plate having an average in-plane
retardation of not larger than 20 nm, a transparent film having an average
in-plane retardation of not larger than 20 nm, and an adhesive layer
having a refractive index different by 0.1 or less from that of the
transparent film. The transparent film is bonded to the transparent resin
plate through the adhesive layer and wherein in the transparent film
includes a repetitive prismatic structure constituted by optical path
control slopes which are disposed on an outer surface of the transparent
film and which are aligned in a substantially predetermined direction so
that each of the optical path control slopes is inclined at an inclination
angle in a range of from 35 to 48 degrees with respect to a film plane.
