Patent ID: 7658531
Filing Date: 2010-02-09
Classification: G02B

Abstract:
1. A backlight device that forms a flat fluorescent light source for illuminating a flat panel display device, comprising: a light guide panel having a diffraction pattern for emitting light through an emission surface of the light guide panel by diffracting light entering the light guide panel; and a chromatic dispersion compensation member that is an optical transmitting member located on a light emission side of the light guide panel and has a lattice pattern that reverses a portion of chromatically dispersed light emitted from the light guide panel with respect to a line that is vertical with respect to the emission surface of the light guide panel, and transmits the other portion of chromatically dispersed light emitted from the light guide panel, wherein the lattice pattern includes alternating protruded portions and concaved portions, and an aspect ratio of the lattice pattern, which is a ratio of a depth with respect to a width of the lattice pattern, is 5 or more, where the width of the lattice pattern is a width of the protruded portion, and the depth of the lattice pattern is a length of the protruded portion.