Abstract: Disclosed is a liquid crystal display device, provided with an optical-modulation film including a matrix and birefringent island-in-the-sea yarns having two or more spinning cores arranged in the matrix to considerably reduce production costs and remarkably increase luminance. The optical-modulation film includes birefringent island-in-the-sea yarns whose island portions are grouped based on two or more spinning cores, present in the matrix, thus causing formation of optical modulation interfaces between the island portions and sea portions, thus maximizing optical modulation efficiency, as compared to conventional birefringent fibers.